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  • 1.
    Hedayati, Ali
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Ash transformation in single-pellet combustion and gasification of biomass with special focus on phosphorus2020Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    The utilization of different biomass feedstocks in thermal conversion systems can contribute towards mitigation of global warming. However, the formation of different ash fractions (i.e., bottom ash, and fly ash) during thermal conversionof biomass can cause several ash-related problems such as deposit formation, slagging, and particle emissions, all of which may limit its usage as an energy source. It has been found that phosphorus (P), even in relatively low concentrations, can play a vitalrole in the abovementioned ash-related problems. However, the ash transformation reactions occurring in the thermal conversion of P-bearing biomass assortments are not fully understood and rarely described in the literature. Therefore, an understanding ofthe phenomena associated with ash transformations with a special focus on P is crucial.

    The overall objective was to determine the ash transformation and release of P duringsingle-pelletthermochemical conversion ofdifferent types of agricultural and forest fuelsin the low to medium temperature range (600-950 °C). Different agricultural biomasses (poplar, wheat straw, grass, and wheat grain residues), as well as forest residues (bark, twigs, and a mixture of bark and twigs) were used. Thebark and poplar fuels represent a fuel rich in K and Ca with minor P contents. The wheat straw, grass, and twigs represent a typical Si- and K-rich fuel with minor and moderate P contents. The wheat grain residues represent a typical K- and P-rich fuel witha considerable amount of Mg. The produced residual materials, i.e. chars and ashes, were characterized by SEM-EDS, XRD, and ICP-OES. The experimental results were interpreted with support from thermodynamic equilibrium calculations (TECs).

    The overall findings are that the majority of P (>80%) in all the studied fuels remained in the final condensed residues, and that the main fraction of P release occurred during the devolatilization stage. The chemical form of P in the residuesis strongly dependent on the relative concentrations of other major ash-forming elements such as K, Ca, and Si, as well as the type of association of P in the pure fuel. For woody-based fuels rich in Ca and K (poplar, bark, and twigs in this study), P in theash is generally found in the form of crystalline hydroxyapatite. For herbaceous fuels rich in Si and K (wheat straw and grass), P in the ash is generally found in Ca5(PO4)3OH, Ca15(PO4)2(SiO4),KCaPO4, and K-Ca/Mg phosphosilicate melts. For wheat grain residues rich in P, K, and Mg, P in the ash is found in crystalline forms K4Mg4(P2O7)3, K2MgP2O7,K2CaP2O7, and KMgPO4, as well as amorphous K-Mg/Ca phosphates.

    The obtained new knowledge can be used to find practical measures to mitigate ash-related problems during thermochemical conversion of P-bearing biomass fuels. It can also be used to find optimal pyrolysis process conditions to obtain biocharsuitable as alternative fuels and reducing agents in the metallurgical industry.

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  • 2.
    Zhao, Nana
    et al.
    College of Chemical Engineering, State Key Laboratory of Materials-oriented Chemical Engineering, Nanjing Tech University, 30# Puzhu South Road, Nanjing, 211816, PR China.
    Deng, Jiawei
    College of Chemical Engineering, State Key Laboratory of Materials-oriented Chemical Engineering, Nanjing Tech University, 30# Puzhu South Road, Nanjing, 211816, PR China.
    Zhu, Yudan
    College of Chemical Engineering, State Key Laboratory of Materials-oriented Chemical Engineering, Nanjing Tech University, 30# Puzhu South Road, Nanjing, 211816, PR China.
    Chen, Yaojia
    College of Chemical Engineering, State Key Laboratory of Materials-oriented Chemical Engineering, Nanjing Tech University, 30# Puzhu South Road, Nanjing, 211816, PR China.
    Qin, Yao
    College of Chemical Engineering, State Key Laboratory of Materials-oriented Chemical Engineering, Nanjing Tech University, 30# Puzhu South Road, Nanjing, 211816, PR China.
    Ruan, Yang
    College of Chemical Engineering, State Key Laboratory of Materials-oriented Chemical Engineering, Nanjing Tech University, 30# Puzhu South Road, Nanjing, 211816, PR China.
    Zhang, Yumeng
    College of Chemical Engineering, State Key Laboratory of Materials-oriented Chemical Engineering, Nanjing Tech University, 30# Puzhu South Road, Nanjing, 211816, PR China.
    Gao, Qingwei
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap. College of Chemical Engineering, State Key Laboratory of Materials-oriented Chemical Engineering, Nanjing Tech University, 30# Puzhu South Road, Nanjing, 211816, PR China.
    Lu, Xiaohua
    College of Chemical Engineering, State Key Laboratory of Materials-oriented Chemical Engineering, Nanjing Tech University, 30# Puzhu South Road, Nanjing, 211816, PR China.
    Atomistic insights into the effects of carbonyl oxygens in functionalized graphene nanopores on Ca2+/Na+ sieving2020Ingår i: Carbon, ISSN 0008-6223, E-ISSN 1873-3891, Vol. 164, s. 305-316Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Residual Ca2+ decreases the efficiency and increases the power consumption of the chlor-alkali industry. However, Ca2+ and Na+ sieving is challenging due to the similar ionic radii of these cations. Inspired by the presence of carbonyl oxygens in key selective filters of biological Ca2+ and Na+ channels, we used molecular dynamics to investigate the effects of carbonyl oxygen atoms in modified graphene nanopores of various sizes (characteristic diameters: 0.57–1.50 nm) on Ca2+/Na+ sieving. The results demonstrated that selectivity is closely associated with the different roles of the carbonyl oxygen atoms. In small nanopores, Ca2+ sheds increased numbers of water molecules due to the predominant steric effect of carbonyl oxygen atoms. Thus, Ca2+ must overcome a higher energy barrier than Na+. This requirement prevents the passage of Ca2+. In large nanopores, carbonyl oxygen atoms do preferentially substitute water molecules outside the first hydration shell of Ca2+ compared with those outside the first hydration shell of Na+, thereby hindering Na+ departure from the nanopore. These findings provide useful guidance for the further development of Ca2+ separation materials as sensors and ion separators.

  • 3.
    Nwachukwu, Chinedu M
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Toffolo, Andrea
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Wetterlund, Elisabeth
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Biomass-based gas use in Swedish iron and steel industry: Supply chain and process integration considerations2020Ingår i: Renewable energy, ISSN 0960-1481, E-ISSN 1879-0682, Vol. 146, s. 2797-2811Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Substitution of fossil gaseous fuels with biomass-based gases is of interest to the iron and steel industry due to its role in the mitigation of anthropogenic CO2emissions. In switching from fossil fuels to biomass-based gases, a systems analysis of the full value chain from biomass supply to the production and supply of final gas products becomes crucial. This study uses process and heat integration methods in combination with a supply chain evaluation to analyse full value chains of biomass-based gases for fossil gas replacement within the iron and steel industry. The study is carried out as a specific case study in order to understand the implications of utilizing bio-syngas/bio-SNG as heating fuels in iron- and steel-making, and to provide insights into the most sensitive parameters involved in fuel switching. The results show a significant cost difference in the fuel production of the two gas products owing to higher capital and biomass use in the bio-SNG value chain option. When tested for sensitivity, biomass price, transportation distance, and capital costs show the most impact on fuel production costs across all options studied. Trade-offs associated with process integration, plant localisation, feedstock availability and supply were found to varying extents.

  • 4.
    Sandberg, Erik
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Capturing Swedish Industry Transition towards Carbon Neutrality in a National Energy System Model2020Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Industry is responsible for approximately 30 % of the total emissions of greenhouse gases, both globally and in Sweden. Given the climate targets set out in the Paris agreement, the industry is facing a challenging future, requiring effective policies to aid the transition. Energy system optimisation models are commonly used for analysing the impact from different policies and for assessing the transition to a climate-neutral energy system. In the past, the primary focus of the models has been on the stationary energy sector, and less on the industry. This thesis work, therefore, aims to improve energy system optimisation models as a tool for decision support and policy analysis about the industry. An improved modelling structure of the industry sector is developed and a wide range of future technology options that can support the transition to a climate-neutral industry is identified. The improved model is then applied in different scenario analysis, assessing how the Swedish industry can meet net-zero CO2-emission under resource limitations.

    The methodology applied is energy system analysis with a focus on the process of modelling, an iterative process of i) model conceptualisation, ii) model computation and iii) model result interpretation. Two different models for the evaluation of the Swedish industry are developed and used; a TIMES based model (cost-minimisation) and a small linear optimisation model (resource optimisation).

    An outcome from developing the model structure was that the following important aspects need to be represented in the model to capture the transition to a climate-neutral industry sector; i) synergies between different types of industrial processes, ii) setup of process chains based on important tradeable materials, iii) detailed technology representation. When identifying and analysing future technologies, it was concluded that there are plenty of technology options for Swedish industry to become fossil-free. Technology options were identified that enable all studied site categories (representing approximately 92 % of the CO2 emissions from Swedish industry in 2015) to reach net-zero CO2-emissions via either electrification (direct electric heating or via power to gas) or biofuels usage. CCS options were implemented for iron and steel industry, chemical industry, cement- and limestone industry and aluminium industry, and for most of the industrial energy conversion technologies. Although technology options for deep reductions in CO2 emissions exist, many of them require further development to enable full-scale implementation, as concluded in paper III.

    The scenario analysis performed in paper I and paper II gives insights into key resources and technologies enabling the industry to reach net-zero CO2 emissions. About resources, biomass is seemingly the most cost-efficient option for reaching ambitious climate targets, e.g. according to the findings in paper II biomass is consistently preferred over electrified alternatives. However, the availability of biomass is limited, and increased electrification of technologies is unavoidable to achieve sustainable use of it (as seen in paper I and paper II). Finally, there is not one key enabling technology but rather key groups of enabling technologies that create cross-technology synergies, providing different benefits depending on resource availability and the overall needs of the system in different scenarios.

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  • 5.
    Ma, Chunyan
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Shukla, Shashi Kant
    Technical Chemistry, Department of Chemistry, Chemical-Biological Centre, Umeå University, Umeå, Sweden.
    Samikannu, Rakesh
    Technical Chemistry, Department of Chemistry, Chemical-Biological Centre, Umeå University, Umeå, Sweden.
    Mikkola, Jyri-Pekka
    Technical Chemistry, Department of Chemistry, Chemical-Biological Centre, Umeå University, Umeå, Sweden. Industrial Chemistry & Reaction Engineering, Johan Gadolin Process Chemistry Centre, Åbo Akademi University, Turku , Finland.
    Ji, Xiaoyan
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    CO2 Separation by a Series of Aqueous Morpholinium-Based Ionic Liquids with Acetate Anions2020Ingår i: ACS Sustainable Chemistry & Engineering, ISSN 2168-0485, Vol. 8, nr 1, s. 415-426Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this work, CO2 absorption capacities in a series of aqueous N-alkyl-N-methylmorpholinium-based ILs with acetate as the counterpart anion were investigated. Among these ILs, N-butyl-N-methylmorpholinium acetate ([Bmmorp][OAc]) with the highest CO2 absorption capacity was screened for thermodynamic modeling. The non-random two-liquid model and the Redlich–Kwong equation of state (NRTL-RK model) were used to describe the phase equilibria. The CH4 absorption capacity in the aqueous [Bmmorp][OAc] was also measured in order to verify the results predicted from the thermodynamic modeling, and the comparison shows the reliability of the model prediction. The parameters were embedded into the commercial software Aspen Plus. After that, the aqueous [Bmmorp][OAc] solutions with 30–40 wt % of water were selected to carry out process simulation for CO2 separation from biogas, and it was found that using these aqueous [Bmmorp][OAc] gave rise to lower energy usage and smaller size of equipment than other physical solvents. The results suggest that aqueous [Bmmorp][OAc] solution can be used as an alternative to organic solvents and has the potential to decrease the cost of CO2 separation.

  • 6.
    Chen, Yifeng
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Sun, Yunhao
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap. Key Laboratory of Material and Chemical Engineering, Nanjing Tech University, Nanjing, China.
    Yang, Zhuhong
    Key Laboratory of Material and Chemical Engineering, Nanjing Tech University, Nanjing, China.
    Lu, Xiaohua
    Key Laboratory of Material and Chemical Engineering, Nanjing Tech University, Nanjing, China.
    Ji, Xiaoyan
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    CO2 separation using a hybrid choline-2-pyrrolidine-carboxylic acid/polyethylene glycol/water absorbent2020Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 257, artikel-id 113962Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Developing novel hybrid absorbents is essential for CO2 separation. In this study, the density and viscosity of a hybrid absorbent (choline-2-pyrrolidine-carboxylic acid/polyethylene glycol/water ([Cho][Pro]/PEG200/H2O)) were measured experimentally, and its CO2 solubility was also determined. The excess mole volume and excess Gibbs energy of activation of the hybrid absorbent were further estimated to understand the molecular structure and interactions between [Cho][Pro]/PEG200 and H2O. The CO2 solubilities in [Cho][Pro]/PEG200 and [Cho][Pro]/H2O were analyzed and described using the Redlich–Kwong non-random-two-liquid (RK-NRTL) model. Furthermore, the CO2 solubility in the hybrid absorbent was predicted using the RK-NRTL model and was compared with the new experimental results for verification. The effect of H2O on the CO2 absorption performance was further analyzed. The performance and cost of the hybrid absorbent were compared with those of other commercialized CO2 absorbents. In addition, the recyclability of the hybrid absorbent for CO2 separation was studied. The results of this study indicated that the hybrid absorbent could be promising for CO2 separation.

  • 7.
    Li, Jing
    et al.
    ntelligent Composites Laboratory, Department of Chemical and Biomolecular Engineering, The University of Akron, Akron, Ohio, United States. State Key Laboratory of Materials-Oriented Chemical Engineering, Jiangsu National Synergetic Innovation Center for AdvancedMaterials (SICAM), College of Chemical Engineering, Nanjing Tech University, Nanjing, China. .
    Han, Yylan
    School of Chemistry and Materials Science, University of Science and Technology of China, Hefei, China.
    Lin, Han
    Intelligent Composites Laboratory, Department of Chemical and Biomolecular Engineering, The University of Akron, Akron, Ohio, United States.
    Wu, Nanhua
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap. State Key Laboratory of Materials-Oriented Chemical Engineering, Jiangsu National Synergetic Innovation Center for AdvancedMaterials (SICAM), College of Chemical Engineering, Nanjing Tech University, Nanjing, China.
    Li, Qinkun
    School of Chemistry and Materials Science, University of Science and Technology of China, Hefei, China.
    Jiang, Jun
    School of Chemistry and Materials Science, University of Science and Technology of China, Hefei, China.
    Zhu, Jiahua
    Intelligent Composites Laboratory, Department of Chemical and Biomolecular Engineering, The University of Akron, Akron, Ohio, United States.
    Cobalt-Salen-Based Porous Ionic Polymer: The Role of Valence on Cooperative Conversion of CO2 to Cyclic Carbonate2020Ingår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 12, nr 1, s. 609-618Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Cobalt-salen-based porous ionic polymers, which are composed of cobalt and halogen anions decorated on the framework, effectively catalyze the CO2 cycloaddition reaction of epoxides to cyclic carbonates under ambient conditions. The cooperative effect of bifunctional active sites of cobalt as the Lewis acidic site and the halogen anion as the nucleophile responds to the high catalytic performance. Moreover, density functional theory results indicate that the cobalt valence state and the corresponding coordination group influence the rate-determining step of the CO2 cycloaddition reaction and the nucleophilicity of halogen anions.

  • 8.
    Guo, Ning
    et al.
    Department of Energy and Process Engineering, Faculty of Engineering, NTNU – Norwegian University of Science and Technology, Trondheim, Norway.
    Llamas, Angel David Garcia
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Li, Tian
    Department of Energy and Process Engineering, Faculty of Engineering, NTNU – Norwegian University of Science and Technology, Trondheim, Norway.
    Umeki, Kentaro
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Gebart, Rikard
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Løvås, Terese
    Department of Energy and Process Engineering, Faculty of Engineering, NTNU – Norwegian University of Science and Technology, Trondheim, Norway.
    Computational fluid dynamic simulations of thermochemical conversion of pulverized biomass in a dilute flow using spheroidal approximation2020Ingår i: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 271, artikel-id 117495Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A drag force model for spheroids, referred as the spheroid model, was implemented in OpenFOAM, in order to better predict the thermochemical conversion of pulverized biomass. Our previous work has found that the spheroid model predicts more dispersed results in terms of particle velocities and local concentrations comparing to other conventional particle models under non-reactive conditions. This work takes the spheroid model one step further, by validating against experiments performed under reactive conditions with a newly implemented heat transfer model for spheroids as well as updated devolatilization kinetic parameters. In addition, simulations were conducted in a configuration similar to a pilot-scale entrained flow gasifier for more realistic scenarios. Particle mass and axial velocity development were compared accordingly using four different modelling approaches with increasing complexity. When compared with models of spheroidal shape assumptions, the sphere and simplified non-sphere model predict 61% and 43% longer residence times, respectively. The combination of the spheroid shape assumption with the heat transfer model for spheroids tends to promote drying and devolatilization. On the other hand, the traditional spherical approach leads to longer particle residence times. These opposing effects are believed to be a major contributing factor to the fact that no significant differences among modelling approaches were found in terms of syngas production at the outlet. Furthermore, particle orientation information was reported in both experiments and simulations under reactive conditions. Its dependency on gas velocity gradient under reactive conditions is similar to what was reported under non-reactive conditions.

  • 9.
    Rebbling, Anders
    et al.
    Thermochemical Energy Conversion Laboratory, Department of Applied Physics and Electronics, Umeå University, Sweden.
    Sundberg, Peter
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Fagerström, Jonathan
    Thermochemical Energy Conversion Laboratory, Department of Applied Physics and Electronics, Umeå University, Sweden.
    Carlborg, Markus
    Thermochemical Energy Conversion Laboratory, Department of Applied Physics and Electronics, Umeå University, Sweden.
    Tullin, Claes
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Boström, Dan
    Thermochemical Energy Conversion Laboratory, Department of Applied Physics and Electronics, Umeå University, Sweden.
    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, Sweden.
    Skoglund, Nils
    Thermochemical Energy Conversion Laboratory, Department of Applied Physics and Electronics, Umeå University, Sweden.
    Demonstrating Fuel Design To Reduce Particulate Emissions and Control Slagging in Industrial-Scale Grate Combustion of Woody Biomass2020Ingår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 34, nr 2, s. 2574-2583Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The demand for increased overall efficiency, improved fuel flexibility, and more stringent environmental legislations promotes the development of new fuel- and technology-related concepts for the bioenergy sector. Previous research has shown that careful consideration of the fuel ash composition and the adjustment of the same via various routes, i.e., fuel design, have the potential to alter the ash transformation reactions, leading to, e.g., a reduction of the formation of slag or entrained inorganic ash particles. The objective of the present work was, therefore, to demonstrate the use of fuel design as a primary measure to reduce the emission of PM1 during combustion of woody biomass in medium-scale grate-fired boilers while keeping the slag formation at a manageable level. This was achieved by designing fuel blends of woody biomass with carefully selected Scandinavian peats rich in Si, Ca, and S. The work includes results from three experimental campaigns, performed in three separate grate-fired boilers of different sizes, specifically 0.2 MWth, 2 MWth, and 4 MWth. In one of the campaigns, softwood-based stemwood pellets were copelletized with different additions of peat (5 and 15 wt %) before combustion. In the other campaigns, peat was added in a separate fuel feed to Salix chips (15 wt % peat) and softwood-based stemwood pellets (10 and 20 wt % peat). Particulate matter and bottom ashes were characterized by scanning electron microscopy–energy-dispersive X-ray spectroscopy for morphology and elemental composition as well as by powder X-ray diffraction for crystalline phase composition. The results show that the fuel design approach provided PM1 reduction for all fuel blends between 30 and 50%. The PM1 reduction could be achieved without causing operational problems due to slagging for any of the three commercial boilers used, although an expected increased slagging tendency was observed. Overall, this paper illustrates that fuel design can be implemented on an industrial scale by achieving the desired ash transformation reactions, in this case, leading to a reduction of fine particulate emissions by up to 50% without any operational disturbances due to slag formation on the grate.

  • 10.
    Ahlström, Johan M.
    et al.
    Chalmers University of Technology, Dep. of Space. Earth and Environment, Div. of Energy Technology.
    Zetterholm, Jonas
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Pettersson, Karin
    RISE Research Institutes of Sweden.
    Harvey, Simon
    Chalmers University of Technology, Dep. of Space. Earth and Environment, Div. of Energy Technology.
    Wetterlund, Elisabeth
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Economic potential for substitution of fossil fuels with liquefied biomethane in Swedish iron and steel industry: Synergy and competition with other sectors2020Ingår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 209, artikel-id 112641Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In Sweden, the iron and steel industry (ISI) is a major source of greenhouse gas (GHG) emissions. Most of the emissions result from the use of fossil reducing agents. Nevertheless, the use of fossil fuels for other purposes must also be eliminated in order to reach the Swedish emissions reduction targets. In this study, we investigate the possibility to replace fossil gaseous and liquid fuels used for heating in the ISI, with liquefied biomethane (LBG) produced through gasification of forest residues. We hypothesize that such utilization of fuels in the Swedish ISI is insufficient to independently drive the development of large-scale LBG production, and that other sectors demanding LBG, e.g., for transportation, can be expected to influence the economic potential for the ISI to switch to LBG. The paper investigates how demand for LBG from other sectors can contribute to, or prevent, a phase-out of fossil fuels used for heating purposes in the ISI under different future energy market scenarios, with additional analysis of the impact of a CO2 emissions charge. A geographically explicit cost-minimizing biofuel production localization model is combined with heat integration and energy market scenario analysis. The results show that from a set of possible future energy market scenarios, none yielded more than a 9% replacement of fossil fuels used for heating purposes in the ISI, and only when there was also a demand for LBG from other sectors. The scenarios corresponding to a more ambitious GHG mitigation policy did not achieve higher adoption of LBG, due to corresponding higher biomass prices. A CO2 charge exceeding 200 EUR/tonCO2 would be required to achieve a full phase-out of fossil fuels used for heating purposes in the ISI. We conclude that with the current policy situation, substitution of fossil fuels by LBG will not be economically feasible for the Swedish ISI.

  • 11.
    Hadi Jafari, Pantea
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Wingren, Anders
    Meva Energy AB, Hisings Backa.
    Hellström, J. Gunnar I.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Strömningslära och experimentell mekanik.
    Gebart, Rikard
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Effect of process parameters on the performance of an air-blown entrained flow cyclone gasifier2020Ingår i: International Journal of Sustainable Energy, ISSN 1478-6451, E-ISSN 1478-646X, Vol. 39, nr 1, s. 21-40Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Entrained flow gasification of biomass in a cyclone reactor combined by a gas engine has been applied in Nordic countries as one of the preferred methods for generating combined heat and power in small scales. The purpose of the current study was to optimise the gasification plant efficiency and understanding the influence of operating conditions. The experiments were carried out in a 2.4 MW(th) commercial gasification power plant. The gasifier was operated in optimum at a rather low lambda around 0.27 and a temperature of 950°C. The lower heating value of the clean product gas at this lambda was 5.95 MJ/Nm3. The experimental results also were compared with the predicted values from thermodynamic equilibrium calculations by Factsage 7.0. The performance of five different types of biofuels including torrefied spruce, peat, rice husk, bark and stemwood were assessed and compared with each other using thermodynamic equilibrium and available experimental data.

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  • 12.
    Li, Zheng
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap. State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemical and Chemical Engineering, Nanjing Tech University, Nanjing, China.
    Ji, Xiaoyan
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Yang, Zhuhong
    State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemical and Chemical Engineering, Nanjing Tech University, Nanjing, China.
    Lu, Xiaohua
    State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemical and Chemical Engineering, Nanjing Tech University, Nanjing, China.
    Experimental studies of air-blast atomization on the CO2 capture with aqueous alkali solutions2020Ingår i: Chinese Journal of Chemical Engineering, ISSN 1004-9541, E-ISSN 2210-321X, Vol. 27, nr 10, s. 23901-2396Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this work, an air-blast atomizing column was used to study the CO2 capture performance with aqueous MEA (mono-ethanol-amine) and NaOH solutions. The effects of gas flow rate, the liquid to gas ratio (L/G), the CO2 concentration on the CO2 removal efficiency (η) and the volumetric overall mass transfer coefficient (KGav) were investigated. The air-blast atomizing column was also compared with the pressure spray tower on the studies of the CO2 capture performance. For the aqueous MEA and NaOH solutions, the experimental results show that the ηdecreases with increasing gas flow rate and CO2 concentration while it increases with increasing L/G. The effects on KGav are more complicated than those for η. When the CO2 concentration is low (3 v/v%), KGav increases with increasing gas flow rate while decreases with increasing L/G. However, when the CO2 concentration is high (9.5 v/v%), as the gas flow rate and L/G increases, KGav increases first and then decreases. The aqueous MEA solution achieves higher η and KGav than the aqueous NaOH solution. The air-blast atomizing column shows a good performance on CO2 capture.

  • 13.
    Häggström, Gustav
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Experimental studies of ash transformation processes in thermochemical conversion of P-rich biomass and sludge2020Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    The efficient use of resources and sustainable recovery of various materials are important to minimize the anthropogenic impact on the climate and environment. One such resource is the phosphorus present in manure and sewage sludge. Various technologies are currently being developed to recover the phosphorus for the use of fertilizers in agricultural applications. Thermochemical conversion presents an opportunity to recover energy from these materials. At the same time, elements can be recovered in ash fractions, potentially harmful organic substances can be destroyed and heavy metals fractionated from the P. Mono-combustion of sewage sludge mainly produce apatite, which is not plant available and useful for fertilization. Co-combustion/-gasification with other fuels enables modification of ash transformation pathways and also remedy potential problems, such as bed agglomeration, associated with e.g. agricultural residues used as fuels. This thesis aims to increase the current knowledge in ash transformation of phosphorus-rich materials in cocombustion/-gasification with woody and agricultural fuels in process temperatures relevant for fluidized bed systems. The work focuses on i) possibility for formation of plant-available K-bearing phosphates ii) the effect of fuel ash composition and chemical association of P in the fuel on the distribution and speciation of P and iii) interaction of P-rich ash with bed material in fluidized beds. Experiments were carried out in bench-scale bubbling fluidized bed (BFB), macro-TGA (thermogravimetric analysis) combustion reactors and a dual fluidized bed (DFB) gasification reactor. Fuels studied were mixtures of chicken litter together with wheat straw and bark, and mixtures of digested sewage sludge combined with wheat straw and sunflower husk. Ash fraction and bed materials were collected and analyzed using ICP-OES/MS, SEM-EDS and XRD techniques. For the mixture of chicken litter and K- and Si-rich wheat straw, combusted in BFB, P and Si together with K and Ca formed homogeneous ash particles with large amounts of potentially amorphous iv content. A similar behavior was observed in sewage sludge and wheat straw mixtures where P and Si were likely present in a melt that is amorphous after extraction. In addition to these particles, P was also found in crystalline compounds such as hydroxyapatite, whitlockite and CaKPO4. For mixtures with Ca-rich bark, most of the phosphate formed was in the form of hydroxyapatite. In the interaction of ash with bed material, P captures Ca and K in phosphates, decreasing the interactions of these elements with the bed material, and thus can decrease the risk for bed agglomeration. The findings show that it is possible to modify the ash transformation of P towards K-bearing phosphates by co-combustion. Furthermore, they suggest that it is possible to recover most of the phosphorus in coarse ash fractions through co-combustion of P-rich materials with agricultural fuels. This means that P and volatile heavy metals can be separated into different ash fractions. This also increases the possibility of utilizing existing boilers for recovery of P as well as increased their flexibility to different fuels. To further validate the agricultural value of the produced ashes, plant growth studies have to be performed.

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  • 14.
    Falk, Joel
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Skoglund, Nils
    Thermochemical Energy Conversion Laboratory, Department of Applied Physics and Electronics, Umeå University, Umeå, Sweden.
    Grimm, Alejandro
    Department of Forest Biomaterials and Technology, Swedish University of Agricultural Sciences, Umeå, Sweden.
    Öhman, Marcus
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Fate of Phosphorus in Fixed Bed Combustion of Biomass and Sewage Sludge2020Ingår i: The Open Fuels & Energy Science Journal, ISSN 1876-973X, E-ISSN 1876-973X, Vol. 34, nr 4, s. 4587-4594Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The recovery of phosphorus (P) from societal waste streams, such as sewage sludge, could make a significant contribution to alleviating the global dependency upon non-renewable phosphate sources, such as phosphate rock. This study aims to determine the effect of fuel ash composition, chemical association, and combustion technology on the fate of P in ashes from the combustion of sewage sludge and biomass blends to enable more efficient P recovery from combustion ashes. Experiments were performed in a fixed bed pellet burner (20 kW), combusting two sewage sludge blends and three biomass blends of similar fuel ash composition but with different P source (sewage sludge, dried distiller’s grain with solubles, or phosphoric acid). Slag, bottom ash, and particulate matter samples were collected and analyzed by scanning electron microscopy–energy-dispersive X-ray spectroscopy and X-ray diffraction for morphology and elemental and crystalline phase composition and compared to results from experiments in fluidized bed combustion using the same fuel blends reported separately. The distribution and elemental composition of ash fractions indicated that sub-micrometer particles contained a minor share of fuel P, with the significant share of fuel P found in the slag and bottom ash fractions. No apparent difference in phosphate speciation could be observed between the slag and bottom ash from sewage sludge blends and biomass blends, with a range of crystalline Ca, Mg, and K phosphates detected in the ash. By comparison, only Ca-rich phosphates were detected in the ashes from the combustion of the sewage sludge blends in the bench-scale fluidized bed. The difference in P speciation between the technologies was attributed to a difference in the process temperature between the two technologies. In comparison to fluidized bed combustion, fixed bed combustion favored the formation of (Ca, Mg)–K phosphates rather than Ca phosphates for similar fuel blends.

  • 15.
    Häggström, Gustav
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Fürsatz, Katharina
    Bioenergy2020+ GmbH, Austria. Institute of Chemical, Environmental & Bioscience Engineering, TU Wien, Austria.
    Kuba, Matthias
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap. Bioenergy2020+ GmbH, Austria. Thermochemical Energy Conversion Laboratory, Department of Applied Physics and Electronics, Umeå University, Sweden. Institute of Chemical, Environmental & Bioscience Engineering, TU Wien, Austria .
    Skoglund, Nils
    Thermochemical Energy Conversion Laboratory, Department of Applied Physics and Electronics, Umeå University, Sweden.
    Öhman, Marcus
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Fate of Phosphorus in Fluidized Bed Cocombustion of Chicken Litter with Wheat Straw and Bark Residues2020Ingår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 34, nr 2, s. 1822-1829Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This study aims to determine the fate of P during fluidized bed co-combustion of chicken litter (CL) with K-rich fuels [e.g., wheat straw (WS)] and Ca-rich fuels (bark). The effect of fuel blending on phosphate speciation in ash was investigated. This was performed by chemical characterization of ash fractions to determine which phosphate compounds had formed and identify plausible ash transformation reactions for P. The ash fractions were produced in combustion experiments using CL and fuel blends with 30% CL and WS or bark (B) at 790–810 °C in a 5 kW laboratory-scale bubbling fluidized bed. Potassium feldspar was used as the bed material. Bed ash particles, cyclone ash, and particulate matter (PM) were collected and subjected to chemical analysis with scanning electron microscopy–energy-dispersive X-ray spectrometry (SEM–EDS) and X-ray diffraction. P was detected in coarse ash fractions only, that is, bed ash, cyclone ash, and coarse PM fraction (>1 μm); no P could be detected in the fine PM fraction (<1 μm). SEM–EDS analysis showed that P was mainly present in K–Ca–P-rich areas for pure CL as well as in the ashes from the fuel blends of CL with WS or B. In the WS blend, P was found together with Si in these areas. The crystalline compound containing P was hydroxyapatite in all cases as well as whitlockite in the cases of pure CL and WS blend, of which the latter compound has been previously identified as a promising plant nutrient. The ash fractions from CL and bark blend only contained P in hydroxyapatite. Co-combustion of CL together with WS appears to be promising for P recovery, and ashes with this composition could be further studied in plant growth experiments.

  • 16.
    Millot, Ariane
    et al.
    Mines ParisTech, PSL Research University, Centre for Applied Mathematics.
    Krook-Riekkola, Anna
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Maïzi, Nadia
    Mines ParisTech, PSL Research University, Centre for Applied Mathematics.
    Guiding the future energy transition to net-zero emissions: Lessons from exploring the differences between France and Sweden2020Ingår i: Energy Policy, ISSN 0301-4215, E-ISSN 1873-6777, Vol. 139, artikel-id 111358Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Despite similarities in their current energy mixes, France and Sweden's pathways have been very different since the 1970s, when both systems were highly dependent on fossil fuels. After the oil crisis, both countries chose to reduce their oil consumption by developing nuclear power. However, Sweden pursued a more diversified energy policy that has subsequently allowed it to reduce its CO2 emissions. Today, both countries have committed to a carbon neutrality goal: by 2045 for Sweden and 2050 for France. In order to understand the key factors that can drive energy transition toward a carbon neutrality goal, we propose to compare the past energy transitions in France and Sweden, two countries that have significantly reduced their CO2 emissions and fossil fuel dependency. To assess the impacts of the current energy system and its regulations on the feasibility of meeting carbon neutrality, we use TIMES bottom-up energy system optimization models. The results show that France faces more challenges in transforming its energy system than Sweden i.e. an increase in power production, a decrease in gas consumption, the replacement of heating systems in buildings, and the electrification of industry, thus confirming that its energy policy has to be driven with a long-run perspective.

  • 17.
    Chen, Jingjing
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap. State Key Laboratory of Material-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 211816, PR China.
    Hai, Zhong
    State Key Laboratory of Material-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 211816, PR China.
    Lu, Xiaohua
    State Key Laboratory of Material-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 211816, PR China.
    Wang, Changsong
    State Key Laboratory of Material-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 211816, PR China.
    Ji, Xiaoyan
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Heat-transfer enhancement for corn straw slurry from biogas plants by twisted hexagonal tubes2020Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 262, artikel-id 114554Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Heat-transfer geometries that enhance heat transfer performance for slurries increase the net raw biogas production in the bio-methane process. In this study, the precise temperature-dependent rheologies of corn straw slurry with 6 and 8% total solid were determined, collected, and modeled to conduct a numerical simulation via CFD, the first instance of such research. Subsequently, the reliability of the numerical results was verified with heat-transfer experiments. The heat-transfer performances of the circular, twisted square and twisted hexagonal tubes were estimated numerically, ultimately showing that the twisted hexagonal tube performed optimally with an enhancement factor of up to 2.0 in the turbulent region, compared to the circular tube. Based on the numerical results, the mechanism of heat-transfer enhancement was revealed, showing balanced radial mixing and the near-wall shear effect that leads to a strong and continuous shear rate under a considerable radial-flow intensity. An engineering equation was obtained for the performance evaluation, and the waste-heat recovery from corn straw slurry was analyzed, showing the twisted hexagonal tube can increase the net raw biogas production by up to 17.0% compared to the circular tube.

  • 18.
    Shen, Gulou
    et al.
    National & Local Joint Engineering Research Center for Deep Utilization Technology of Rock-salt Resource, Faculty of Chemical Engineering, Huaiyin Institute of Technology, Huaian 223003, China.
    Sun, Yunhao
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap. State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 210009, China.
    Wang, Yu
    National & Local Joint Engineering Research Center for Deep Utilization Technology of Rock-salt Resource, Faculty of Chemical Engineering, Huaiyin Institute of Technology, Huaian 223003, China.
    Lu, Xiaohua
    State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 210009, China.
    Ji, Xiaoyan
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Interfacial structure and differential capacitance of ionic liquid/graphite interface: A perturbed-chain SAFT density functional theory study2020Ingår i: Journal of Molecular Liquids, ISSN 0167-7322, E-ISSN 1873-3166, Vol. 310, artikel-id 113199Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The perturbed-chain statistical associating fluid theory (PC-SAFT) equation of state (EoS) was combined with the electrostatic free energy from the mean spherical approximation (MSA) theory, and applied to represent densities of pure imidazolium ionic liquids (ILs) with anion [BF4]−. The PC-SAFT parameters of cations were linearized with their molar mass and obtained by simultaneously fitting the model predictions to experimental densities of some ILs. The PC-SAFT-MSA model provides accurate correlations and predictions of densities comparing with experimental data. Then a classical density functional theory (DFT) was developed based on PC-SAFT-MSA. The DFT model was applied to explore the structure and differential capacitance of the electrical double layer (EDL) in ILs on graphite. The model predicts similar density profiles for both cation and anion on a neutral surface, and layered structure with alternating layers of cations and anions on a charged surface. The charge inversion phenomena were also studied based on ion distributions. We further studied the effects of the alkyl chain length, temperature and non-electrostatic solid-fluid interactions on the differential capacitance of the EDL. The model provides bell-shaped differential capacitance curves. The peak positions of differential capacitance curves shift toward positive potentials as ions size asymmetry increases in agreement with previous experiments and simulations studies. The maximum capacitance decreases with increasing alkyl chain length as well as increasing temperature.

  • 19.
    Fischer, Robert
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap. Luleå University of Technology.
    Investigation into sustainable energy systems in Nordic municipalities2020Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [sv]

    Kommunala energisystem i nordiska miljöer möter flera utmaningar: det kalla klimatet, storskaliga industrier, en stor andel elvärme och långa distanser driver energiförbrukningen. Medan åtgärder vidtas på efterfrågesidan för att minimera energianvändningen, kan utsläppsminskande åtgärder inom gruvdrift, industrier, uppvärmningen och transportsektorn öka förbrukningen av el och biobränslen. Fortsatt tillväxt av intermittent vind- och solkraft ökar elproduktion, men den planerade avvecklingen av svensk kärnkraft kommer att utmana tillförlitligheten i elsystemet i de nordiska länderna. Flaskhalsar i överförings- och distributionsnäten kan begränsa en potentiell tillväxt av elanvändningen i stadsområden, begränsa ny intermittent utbud, och påverka elutbyte mellan länderna. Miljöhänsyn kan begränsa ökad användning av biomassa. Lokala myndigheter är engagerade i att bidra till nationella klimatmål, samtidigt som de följer sina egna mål för ekonomisk utveckling, ökad självförsörjning av energi och överkomliga energikostnader.

    Mot bakgrund av dessa omständigheter undersöker denna avhandling befintliga tekniska och ekonomiska potentialer för förnybar energi i Norden med fokus på de nordliga länen i Finland, Norge och Sverige. Forskningen syftar vidare till att utveckla optimala lösningar för hållbara nordiska kommunala energisystem, där samspelet mellan stora energisektorer studeras, med tanke på att minimera årliga energisystemkostnader och samtidigt minska koldioxidutsläppen samt analysera påverkan på elimport till och export från kommunen.

    Denna forskning formulerar ett integrerad kommunalt energisystem som multimåloptimeringsproblem (multi-objective optimisation problem - MOOP), som löses genom att kombinera simuleringsverktyget EnergyPLAN med en evolutionär algoritm implementerad i Matlab. I ett första steg studeras kopplingen av el- och värmesektorerna, och i ett andra steg effekterna av en integrerad och alltmer förnybar transportsektor på energisystemet. Känslighetsanalys på viktiga ekonomiska parametrar och på olika utsläppsfaktorer utförs. Piteå (Norrbottens län, Sverige) är en typisk nordisk kommun som fungerar som en fallstudie för detta arbete.

    Forskningens slutsatser innebär att det finns betydande teknisk-ekonomiska potentialer för de undersökta förnybara resurserna. Optimeringsresultaten visar att koldioxidutsläppen från ett nordiskt kommunalt energisystem kan minskas med cirka 60% utan en avsevärd ökning av de totala energisystemkostnaderna och att den högsta elimporten kan minskas med upp till 38%. Resultat för år 2030 visar att transportsektorn kan ha en mycket hög elektrifieringsgrad och samtidigt används biobränslen i tunga fordon. Optimala lösningar är mycket känsliga för elpriser, räntor och utsläppsfaktorer.

    Detta arbete ger viktiga insikter om strategier för koldioxidminskning för integrerade energisektorer i ett perspektiv på nordiska kommuner. Min framtida forskning kommer att förfina transportmodellen, utveckla och tillämpa ett ramverk för beslutsanalys med flera kriterier (multi-criteria decision analysis - MCDA) som ska stödja lokala myndigheter att fastställa tekniskt och ekonomiskt hållbara lösningar i deras energiplanering.

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  • 20.
    Wang, Yong-Lei
    et al.
    Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden.
    Li, Bin
    School of Chemical Engineering and Technology, Sun Yat-sen University, Zhuhai 519082, P. R. China.
    Sarman, Sten
    Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden.
    Mocci, Francesca
    Department of Chemical and Geological Sciences, University of Cagliari, I-09042 Monserrato, Italy.
    Lu, Zhong-Yuan
    State Key Laboratory of Supramolecular Structure and Materials, Institute of Theoretical Chemistry, Jilin University, Changchun 130021, P. R. China.
    Yuan, Jiayin
    Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden.
    Laaksonen, Aatto
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap. Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden. State Key Laboratory of Materials-Oriented and Chemical Engineering, Nanjing Tech University, Nanjing 210009, P. R. China. Centre of Advanced Research in Bionanoconjugates and Biopolymers, Petru Poni Institute of Macromolecular Chemistry, 700487 Iasi, Romania.
    Fayer, Michael D.
    Department of Chemistry, Stanford University, Stanford, California 94305, United States.
    Microstructural and Dynamical Heterogeneities in Ionic Liquids2020Ingår i: Chemical Reviews, ISSN 0009-2665, E-ISSN 1520-6890Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    Ionic liquids (ILs) are a special category of molten salts solely composed of ions with varied molecular symmetry and charge delocalization. The versatility in combining varied cation–anion moieties and in functionalizing ions with different atoms and molecular groups contributes to their peculiar interactions ranging from weak isotropic associations to strong, specific, and anisotropic forces. A delicate interplay among intra- and intermolecular interactions facilitates the formation of heterogeneous microstructures and liquid morphologies, which further contributes to their striking dynamical properties. Microstructural and dynamical heterogeneities of ILs lead to their multifaceted properties described by an inherent designer feature, which makes ILs important candidates for novel solvents, electrolytes, and functional materials in academia and industrial applications. Due to a massive number of combinations of ion pairs with ion species having distinct molecular structures and IL mixtures containing varied molecular solvents, a comprehensive understanding of their hierarchical structural and dynamical quantities is of great significance for a rational selection of ILs with appropriate properties and thereafter advancing their macroscopic functionalities in applications. In this review, we comprehensively trace recent advances in understanding delicate interplay of strong and weak interactions that underpin their complex phase behaviors with a particular emphasis on understanding heterogeneous microstructures and dynamics of ILs in bulk liquids, in mixtures with cosolvents, and in interfacial regions.

  • 21.
    Gojkovic, Zivan
    et al.
    Department of Chemistry, Umeå University.
    Lu, Yi
    Department of Chemistry, Umeå University.
    Ferro, Lorenza
    Department of Chemistry, Umeå University.
    Toffolo, Andrea
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Funk, Christiane
    Department of Chemistry, Umeå University.
    Modeling biomass production during progressive nitrogen starvation by North Swedish green microalgae2020Ingår i: Algal Research, ISSN 2211-9264, Vol. 47, artikel-id 101835Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Five newly isolated green algal species from Northern Sweden and one culture collection strain were tested for their ability to remove nitrogen and accumulate carbohydrates and neutral lipids (TAGs) under progressive nitrogen starvation. All six microalgal species increased biomass during N starvation, the amount of proteins decreased, and species dependent either TAGs and/or carbohydrates accumulated. Biomass of the algal strains Coelastrella sp. 3-4, Scenedesmus sp. B2-2 and S. obliquus RISE (UTEX 417) had very low final TAG content (≤3.4%) and high carbohydrate content (>41%) at the end of the starvation period. C. astroideum RW10 accumulated 9.2% TAGs and 53.9% carbohydrates during N-starvation; due to its modest growth rate (1.60 g/L and 1.06 1/day) resulting in low final biomass concentration, its cumulativeTAG and carbohydrate productivity were poor (175 mgTAG/system and 1.03 gCARBS/system). C. vulgaris 13-1 preferentially accumulated TAGs (10.3%) over carbohydrates (35%), with low minimal and maximal N quotas (2.27 and 11.6 mM/gDW) in its biomass and a very high growth rate (1.86 1/day) and cumulative TAGs productivity (278 mgTAG/system). Desmodesmus sp. RUC2 had the highest final biomass concentration (3.48 g/L) as well as cumulative TAG and carbohydrate productivity (269 mgTAG/system and 1.79 gCARBS/system). This species had the lowest minimal and maximal N quotas (1.58 and 8.50 mM/gDW) of all tested species, it can produce high amounts of biomass even when the available nitrogen concentration is low.

    A Droop's mathematical model with four basic parameters was applied to interpret the experimental data on N assimilation and biomass production under N starvation. The model corresponded well to the experimental data and therefore can successfully be applied to predict biomass production and N assimilation in Nordic algal species.

  • 22.
    Sun, Yunhao
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Modeling ionic liquids with ePC-SAFT ─ properties and gas solubilities2020Licentiatavhandling, monografi (Övrigt vetenskapligt)
    Abstract [en]

    Global warming is now widely recognized as being the biggest global issue facing human beings. Mitigating CO2 emission from fossil-fueled power plants as well as from transports has become an urgent and worldwide research topic, in which CO2 separation is often needed. Technologies have been developed and commercialized, whereas the cost is still high. Developing new technologies for CO2 separation is one focus research area. Ionic liquids (ILs) are promising absorbents for CO2 separation due to their very low vapor pressure, high solubility and selectivity for CO2 as well as low energy usage for solvent regeneration. To develop IL-based technologies, thermodynamic properties (density, heat capacity, gas solubility, etc.), viscosity, and surface tension of ILs are the prerequisites. As the number of ILs that can be theoretically synthesized is up to an order of 1018, determining all the properties experimentally is impractical, not to mention the time-consuming with high cost. It is desirable to develop theoretical tools to predict the thermodynamics and transport properties of ILs and IL-containing mixtures in a wide temperature and pressure range. In our previous work, the framework of ion-specific electrolyte perturbed-chain statistical associating fluid theory (ePC-SAFT) has been developed with reliable results. However, the work is still limited to the imidazolium-based ILs, and the model performance for other commonly used ILs is still unclear. Meanwhile, it has been pointed out that the model with the parameters fitted to the experimental data may result in pitfalls, and further validation is needed. In this thesis, the ion-specific ePC-SAFT was further developed and extended to the ILs which are composed of the IL-cations ([Cnmim]+ , [Cnpy]+ , [Cnmpy] + , [Cnmpyr]+ , and [THTDP]+ ) and the IL-anions ([Tf2N]- , [PF6] - , [BF4] - , [tfo]- , [DCA]- , [SCN]- , [C1SO4] - , [C2SO4] - , [eFAP]- , Cl- , [Ac]- , and Br- ). Before modeling the properties, a method and scheme were developed to investigate the pitfall when modeling IL with ePC-SAFT. All 96 ILs considered in the thesis were covered. The investigation shows that for most ILs (86 of 96 ILs), the additional fictitious critical temperature is low enough not to affect the calculations at a normal temperature range, and after further phase equilibrium calculation, only one IL ([C8mpy][BF4]) may generate a risk of pitfall occurrence at the temperature and pressure of interest for CO2 separation. The parameters for [Cnmpy]+ may need to be modified in future work. The prediction of the derivative properties (isobaric heat capacity, isochoric heat capacity, speed of sound, isentropic compressibility coefficient, isothermal compressibility coefficient, thermal expansion coefficient, thermal pressure coefficient, and internal pressure) combined with the comparison to the available experimental data shows that ePC-SAFT can provide reliable results for most ILs. ePC-SAFT was used to predict the CO2 solubilities in 46 ILs, and the prediction agrees well with the experimental data in a wide temperature and pressure range for 36 ILs. The addition of an ion-specific binary ii parameter between IL-ion and CO2 can further improve the model performance significantly for the 10 ILs with relatively poor model performance. ePC-SAFT can also provide a reliable prediction for the solubility of other pure gases (CH4, CO, H2, N2, and O2). To further verify the model performance on the viscosity of ILs, ePC-SAFT coupled with the free volume theory (FVT) (i.e., ePC-SAFT-FVT) was studied. Two strategies were applied to adjust the FVT parameters, i.e., molecular-based approach with parameters for each IL (strategy 1) and IL-cation molecular-weight linearized parameters for the ILs in the same homologous series (strategy 2). The comparison with the available experimental viscosities for 96 ILs shows that the strategy 1 can provide reliable results for 89 ILs in a wide temperature and pressure range, while strategy 2 can provide almost similar reliable results as strategy 1. ePC-SAFT-FVT can be further used to predict the viscosity of ILmixtures reliably. The model ePC-SAFT-DGT, i.e., the coupling of ePC-SAFT with the density gradient theory (DGT), was further developed and used to model the interfacial properties of ILs. The comparison with the available experimental surface tensions for 82 ILs shows that the model can represent the surface tension reliably, and the use of the anion-specific influence parameters linearized with the molecular weights of IL-cations allows predicting the surface tension of the ILs in the same homologous series. The density profile on the vaporliquid interface can be further predicted with the influence parameter adjusted by the surface tension. In summary, the ion-specific ePC-SAFT is a suitable tool for IL-systems, which can be highly recommended to be applied in industrial design and optimization.

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  • 23.
    Qin, Yao
    et al.
    College of Chemical Engineering, State Key Laboratory of Materials-oriented Chemical Engineering, Nanjing Tech University.
    Zhao, Nana
    College of Chemical Engineering, State Key Laboratory of Materials-oriented Chemical Engineering, Nanjing Tech University.
    Zhu, Yudan
    College of Chemical Engineering, State Key Laboratory of Materials-oriented Chemical Engineering, Nanjing Tech University.
    Zhang, Yumeng
    College of Chemical Engineering, State Key Laboratory of Materials-oriented Chemical Engineering, Nanjing Tech University.
    Gao, Qingwei
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap. College of Chemical Engineering, State Key Laboratory of Materials-oriented Chemical Engineering, Nanjing Tech University.
    Dai, Zhongyang
    College of Chemical Engineering, State Key Laboratory of Materials-oriented Chemical Engineering, Nanjing Tech University.
    You, Yajing
    College of Chemical Engineering, State Key Laboratory of Materials-oriented Chemical Engineering, Nanjing Tech University.
    Lu, Xiaohua
    College of Chemical Engineering, State Key Laboratory of Materials-oriented Chemical Engineering, Nanjing Tech University.
    Molecular insights into the microstructure of ethanol/water binary mixtures confined within typical 2D nanoslits: The role of the adsorbed layers induced by different solid surfaces2020Ingår i: Fluid Phase Equilibria, ISSN 0378-3812, E-ISSN 1879-0224, Vol. 509, artikel-id 112452Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    With the emergence of membrane separation and heterogeneous catalysis applications that are associated with confined ethanol/water binary mixture in the pores of two-dimensional (2D) nanomaterials, understanding their confined microstructures is the first step for further relevant applications. In this work, molecular dynamics was performed to investigate the microstructure of ethanol/water binary mixture of 5% mole fraction confined within the four typical 2-nm width 2D-nanoslits (i.e. hBN, GO-0.2, GO-0.4 and Ti3C2(OH)2). Results demonstrated that different chemical properties of solid surfaces can induce distinctive microstructures of mixed fluid within the interfacial contact (adsorbed) layer and thus can result in different mobility of water molecules within the subcontact layer. The residence times of water molecules in the subcontact layer were found in the sequence of Ti3C2(OH)2 > hBN > GO-0.4 > GO-0.2, whereas their sequence of diffusion coefficient within the x-z plane was Ti3C2(OH)2 > hBN > GO-0.2 > GO-0.4. Detailed hydrogen bond (HB) microstructure analysis showed that a high average number of HBs (between fluid molecules of the interfacial contact layer and water molecules of the subcontact layer) induced by solid surfaces could facilitate water molecules to reside in the subcontact layer. Moreover, the small average number of HBs between the water molecules themselves in the subcontact layer could lead to high in-plane diffusion coefficients.

  • 24.
    Risberg, Mikael
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Risberg, Daniel
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Numerical calculation of heat losses for crawl space foundation at different locations in Sweden2020Ingår i: Results in Engineering, ISSN 2590-1230, Vol. 7, artikel-id 100141Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Crawl space is one of the most common foundation types in Sweden, and over five hundred thousand family houses have this type of foundation. This study determines how the heat losses variate at six different locations in Sweden from the south to the north. The average heat for a year varied between 1.76 and 3.07 ​W/m2. The maximum heat flux was 4.43 ​W/m2 in Kiruna, while Falsterbo has a maximum heat flux of 3.18 ​W/m2. Minimum heat flux varied between 0.43 and 1.38 ​W/m2. A sensitivity study of the important parameter showed that the temperature is the most important parameter with a decrease in average heat flux of 0.15 ​W/m2 per degree increase in air temperature. Snow depth and snow days are less sensitive and give less than a 2.3% decrease for the average heat flux with a variation of ±50% and ±20 days, respectively.

  • 25.
    Hadi Jafari, Pantea
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Risberg, Mikael
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Hellström, J. Gunnar I.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Strömningslära och experimentell mekanik.
    Gebart, Rikard
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Numerical Simulation of Biomass Gasification in an Entrained Flow Cyclone Gasifier2020Ingår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 34, nr 2, s. 1870-1882Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A transient, two-way coupled Eulerian−Lagrangian computational fluid dynamics model has been developed for numerically investigating the gasification process of wood powder inside a cyclone-shaped reactor. The suggested model has considered heat and mass transfer, drying, devolatilization, and homogeneous and heterogeneous reactions. The model is validated using the experimental data from a commercial entrained-flow cyclone gasifier. The changes in gas composition as a function of equivalence ratio and the behavior of gasification process agreed well with the experimental measurement. Trajectories of individual particles were captured, and the behavior, mass fraction, and temperature distribution of several representative particles in different sizes were studied. Moreover, the model was successful in prediction of produced gas lower heating value, cold gas efficiency, and carbon conversion.

  • 26.
    Sedlmayer, Irene
    et al.
    BEST – Bioenergy and Sustainable Technologies GmbH, Graz, Austria. Technische Universität Wien, Institute of Chemical, Environmental and Bioscience Engineering, Vienna, Austria.
    Bauer-Emhofer, Waltraud
    BEST – Bioenergy and Sustainable Technologies GmbH, Graz, Austria.
    Haslinger, Walter
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap. BEST – Bioenergy and Sustainable Technologies GmbH, Graz, Austria. .
    Hofbauer, Hermann
    Technische Universität Wien, Institute of Chemical, Environmental and Bioscience Engineering, Vienna, Austria.
    Schmidl, Christoph
    BEST – Bioenergy and Sustainable Technologies GmbH, Graz, Austria.
    Wopienka, Elisabeth
    BEST – Bioenergy and Sustainable Technologies GmbH, Graz, Austria.
    Off-gassing reduction of stored wood pellets by adding acetylsalicylic acid2020Ingår i: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 198, artikel-id 106218Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    During transportation and storage of wood pellets various gases are formed leading to toxic atmosphere. Various influencing factors and measures reducing off-gassing have already been investigated. The present study aims at applying an antioxidant, acetylsalicylic acid (ASA), to reduce off-gassing from wood pellets by lowering wood extractives oxidation. Therefore, acetylsalicylic acid was applied in industrial and laboratory pelletizing processes. Pine and spruce sawdust (ratio 1:1) were pelletized with adding 0-0.8% (m/m) ASA. Glass flasks measurements confirmed off-gassing reduction by adding ASA for all wood pellets investigated.The biggest effect was achieved by adding 0.8% (m/m) ASA in the industrial pelletizing experiments where the emission of volatile organic compounds (VOCtot) was reduced by 82% and a reduction of carbon monoxide (CO) and carbon dioxide (CO2) emissions by 70% and 51%, respectively, could be achieved. Even an addition of 0.05% (m/m) ASA led to off-gassing reduction by >10%. A six week storage experiment to investigate the long-term effectivity of ASA addition revealed, that antioxidant addition was effective in reducing CO-, CO2- and VOCtot-release, especially during the first four weeks of the storage experiment, after which time the relative reduction effect was significantly decreased.

  • 27.
    Corrêa Giron, Carolina
    et al.
    Universidade Federal do Triângulo Mineiro, Departamento de Saúde Coletiva, Rua Vigário Carlos, 38025-350 Uberaba, MG, Brazil. Universidade de São Paulo, Departamento de Ciências Biomoleculares, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Av. café, s/no – campus da USP, BR-14040-903 Ribeirão Preto SP, Brazil.
    Laaksonen, Aatto
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap. Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden. State Key Laboratory of Materials-Oriented and Chemical Engineering, Nanjing Tech University, Nanjing, 210009, PR China. Centre of Advanced Research in Bionanoconjugates and Biopolymers, Petru Poni Institute of Macromolecular Chemistry, Aleea Grigore Ghica-Voda, 41A, 700487 Iasi, Romania.
    Barroso da Silva, Fernando L.
    Universidade de São Paulo, Departamento de Ciências Biomoleculares, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Av. café, s/no – campus da USP, BR-14040-903 Ribeirão Preto SP, Brazil. Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695, United States.
    On the interactions of the receptor-binding domain of SARS-CoV-1 and SARS-CoV-2 spike proteins with monoclonal antibodies and the receptor ACE22020Ingår i: Virus Research, ISSN 0168-1702, E-ISSN 1872-7492, artikel-id 198021Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A new betacoronavirus named SARS-CoV-2 has emerged as a new threat to global health and economy. A promising target for both diagnosis and therapeutics treatments of the new disease named COVID-19 is the coronavirus (CoV) spike (S) glycoprotein. By constant-pH Monte Carlo simulations and the PROCEEDpKa method, we have mapped the electrostatic epitopes for four monoclonal antibodies and the angiotensin-converting enzyme 2 (ACE2) on both SARS-CoV-1 and the new SARS-CoV-2 S receptor binding domain (RBD) proteins. We also calculated free energy of interactions and shown that the S RBD proteins from both SARS viruses binds to ACE2 with similar affinities. However, the affinity between the S RBD protein from the new SARS-CoV-2 and ACE2 is higher than for any studied antibody previously found complexed with SARS-CoV-1. Based on physical chemical analysis and free energies estimates, we can shed some light on the involved molecular recognition processes, their clinical aspects, the implications for drug developments, and suggest structural modifications on the CR3022 antibody that would improve its binding affinities for SARS-CoV-2 and contribute to address the ongoing international health crisis.

  • 28.
    Jayawickrama, Thamali Rajika
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Particle-fluid interactions under heterogeneous reactions2020Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Particle-laden flows involve in many energy and industrial processes within a wide scale range. Solid fuel combustion and gasication, drying and catalytic cracking are some of the examples. It is vital to have a better understanding of the phenomena inside the reactors involving in particle-laden flows for process improvements and design. Computational fluid dynamics (CFD) can be a robust tool for these studies with its advantage over experimental methods. The large variation of length scales (101- 10-9 m) and time scales (days-microseconds) is a barrier to execute detailed simulations for large scale reactors. Current state-of-the-art is to use models to bridge the gap between small scales and large scales. Therefore, the accuracy of the models is key to better predictions in large scale simulations.

       Particle-laden flows have complexities due to many reasons. One of the main challenge is to describe how the particle-fluid interaction varies when the particles are reacting. Particle and the fluid interact through mass, momentum and heat exchange. Mass, momentum and heat exchange is presented by the Sherwood number (Sh), drag coefficient (CD) and Nusselt number (Nu) in fluid dynamics. Currently available models do not take into account for the effects of net gas flow generated by heterogeneous chemical reactions. Therefore, the aim of this research is to propose new models for CD and Nu based on the flow and temperature fields estimated by particle-resolved direct numerical simulations (PR-DNS). Models have been developed based on physical interpretation with only one fitting parameter, which is related to the relationship between Reynolds number and the boundary layer thickness. The developed models were compared with the simulation results solving intra-particle flow under char gasification. The drawbacks of models were identied and improvements were proposed.

       The models developed in this work can be used for the better prediction of flow dynamics in large scale simulations in contrast to the classical models which do not consider the effect of heterogeneous reactions. Better predictions will assist the design of industrial processes involving reactive particle-laden flows and make them highly effcient and low energy-intensive.

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  • 29.
    Li, Jing
    et al.
    Intelligent Composites Laboratory, Department of Chemical and Biomolecular Engineering, The University of Akron, Akron, Ohio 44325, United States. State Key Laboratory of Materials-Oriented Chemical Engineering, Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), College of Chemical Engineering, Nanjing Tech University, Nanjing, China.
    Han, Yulan
    Intelligent Composites Laboratory, Department of Chemical and Biomolecular Engineering, The University of Akron, Akron, Ohio 44325, United States State Key Laboratory of Materials-Oriented Chemical Engineering, Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), College of Chemical Engineering, Nanjing Tech University, Nanjing, China.
    Ji, Tuo
    Intelligent Composites Laboratory, Department of Chemical and Biomolecular Engineering, The University of Akron, Akron, Ohio, United States.
    Wu, Nanhua
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap. State Key Laboratory of Materials-Oriented Chemical Engineering, Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), College of Chemical Engineering, Nanjing Tech University, Nanjing , China.
    Lin, Han
    Intelligent Composites Laboratory, Department of Chemical and Biomolecular Engineering, The University of Akron, Akron, Ohio , United States.
    Jiang, Jun
    School of Chemistry and Materials Science, University of Science and Technology of China, Hefei, China.
    Zhu, Jiahua
    Intelligent Composites Laboratory, Department of Chemical and Biomolecular Engineering, The University of Akron, Akron, Ohio , United States.
    Porous Metallosalen Hypercrosslinked Ionic Polymers for Cooperative CO2 Cycloaddition Conversion2020Ingår i: Industrial & Engineering Chemistry Research, ISSN 0888-5885, E-ISSN 1520-5045, Vol. 59, nr 2, s. 676-684Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Metallosalen-based porous ionic polymers have the potential to combine the merits of homogeneous organometallics and heterogeneous porous ionic catalysts in carbon dioxide (CO2) cycloaddition conversion. Herein, a series of porous metallosalen hypercrosslinked ionic polymers (M-HIPs) were synthesized through a simple method. The M-HIPs with high metal and Br anion concentrations were evaluated by catalyzing CO2 cycloaddition with epoxides. Because of the cooperative effect between Br anions and metal active species in the porous channel, M-HIPs exhibited a high CO2 catalytic performance even under ambient conditions. Among the M-HIPs (M = Co, Al, Zn), Co-HIP showed the best catalytic performance for various epoxides and was stable after five runs. Density functional theory calculations support the fact that Co-HIP had the lowest energy barrier, which agreed with the experimental results.

  • 30.
    Trubetskaya, Anna
    et al.
    School of Engineering and Ryan Institute, National University of Ireland Galway, Galway, Ireland.
    Timko, Michael T.
    Chemical Engineering Department, Worcester Polytechnic Institute, Worcester, MA, USA.
    Umeki, Kentaro
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Prediction of fast pyrolysis products yields using lignocellulosic compounds and ash contents2020Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 257, artikel-id 113897Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The effects of lignocellulosic biomass composition on product yields and distributions were studied under high-temperature pyrolysis conditions (800–1250 &#xB0;" role="presentation" style="box-sizing: border-box; margin: 0px; padding: 0px; display: inline; line-height: normal; word-spacing: normal; overflow-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; position: relative;">°°C) in a drop tube reactor. Several types of biomass were studied along with xylan, cellulose, and two types of lignin as model feeds. Among the model feeds, soot yields obtained from lignin pyrolysis were greater than those obtained from cellulose or xylan. Cellulose pyrolysis produced mostly gaseous products, along with small amounts of tars. Impregnation of lignin with alkali metals greatly reduced tar and soot formation, simultaneously increasing the hydrogen content of the syngas product. An empirical model predicted with reasonable accuracy trends in the product yields obtained from pyrolysis of whole biomass samples using as input data obtained from model feeds composition data and the pyrolysis temperature. Reaction temperature and ash content both have a strong influences on char yield, whereas gas yields were mostly affected by the reaction temperature.

  • 31.
    Rebbling, Anders
    et al.
    Thermochemical Energy Conversion Laboratory, Department of Applied Physics and Electronics, Umeå University, 901 87, Umeå, Sweden.
    Näzelius, Ida-Linn
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap. MultCon Multi Consulting AB, Edeforsvägen 62, 960 24, Harads, Sweden.
    Schwabl, Manuel
    BEST – Bioenergy and Sustainable Technologies GmbH, Inffeldgasse 21b, 8010 Graz, Austria.
    Feldmeier, Sabine
    BEST – Bioenergy and Sustainable Technologies GmbH, Inffeldgasse 21b, 8010 Graz, Austria. Technology and Support Centre in the Centre of Excellence for Renewable Resources (TFZ), Schulgasse 18, 94315, Straubing, Germany.
    Schön, Claudia
    Technology and Support Centre in the Centre of Excellence for Renewable Resources (TFZ), Schulgasse 18, 94315, Straubing, Germany.
    Dahl, Jonas
    RISE Built Environment, Research Institutes of Sweden, IDEON, Scheelevägen 17, 223 70 Lund, Beta 5, Sweden.
    Haslinger, Walter
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap. BEST – Bioenergy and Sustainable Technologies GmbH, Inffeldgasse 21b, 8010 Graz, Austria.
    Boström, Dan
    Thermochemical Energy Conversion Laboratory, Department of Applied Physics and Electronics, Umeå University, 901 87, Umeå, Sweden.
    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, 901 87, Umeå, Sweden.
    Prediction of slag related problems during fixed bed combustion of biomass by application of a multivariate statistical approach on fuel properties and burner technology2020Ingår i: Biomass and Bioenergy, ISSN 0961-9534, E-ISSN 1873-2909, Vol. 137, artikel-id 105557Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Slag is related to the melting properties of ash and is affected by both the chemical composition of the fuel ash and the combustion parameters. Chemical analysis of slag from fixed bed combustion of phosphorus-poor biomass show that the main constituents are Si, Ca, K, O (and some Mg, Al, and Na), which indicates that the slag consists of different silicates. Earlier research also points out viscosity and fraction of the ash that melts, as crucial parameters for slag formation. To the authors’ knowledge, very few of the papers published to this day discuss slagging problems of different pelletized fuels combusted in multiple combustion appliances. Furthermore, no comprehensive classification of both burner technology and fuel ash parameters has been presented in the literature so far. The objective of the present paper was therefore to give a first description of a qualitative model where ash content, concentrations of main ash forming elements in the fuel and type of combustion appliance are related to slagging behaviour and potential operational problems of a biomass fuel in different small- and medium scale fixed bed appliances.

    Based on the results from the combustion of a wide range of pelletized biomass fuels in nine different burners, a model is presented for amount of slag formed and expected severity of operational problems. The model was validated by data collected from extensive combustion experiments and it can be concluded that the model predicts qualitative results.

  • 32.
    Cao, Yongkang
    et al.
    Beijing Key Laboratory of Ionic Liquids Clean Process, State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, China College of Chemical Engineering and Environment, China. University of Petroleum, Beijing, Beijing, China.
    Zhang, Xiangping
    Beijing Key Laboratory of Ionic Liquids Clean Process, State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, China. College of Chemical and Engineering, University of Chinese Academy of Sciences, Beijing, China.
    Zeng, Shaojuan
    Beijing Key Laboratory of Ionic Liquids Clean Process, State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, China.
    Liu, Yanrong
    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 Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, China.
    Deng, Chun
    College of Chemical Engineering and Environment, China University of Petroleum, Beijing, Beijing, China.
    Protic Ionic Liquid‐Based Deep Eutectic Solvents with Multiple Hydrogen Bonding Sites for Efficient Absorption of NH32020Ingår i: AIChE Journal, ISSN 0001-1541, E-ISSN 1547-5905, nr e16253Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The emerging of ionic liquids (ILs) provides an efficient and sustainable way to separate and recover NH3 due to their unique properties. However, the solid or highly viscous ILs are not suitable for traditional scrubbing. Therefore, an effective strategy was proposed by combining the protic ILs (PILs) with acidic H and low viscous ethylene glycol (EG) to form IL‐based deep eutectic solvents (DESs) for NH3 absorption. The results indicated that these PIL‐based DESs not only have fast absorption rate, but also exhibit exceptional NH3 capacity and excellent recyclability. The highest mass capacity of 211 mg NH3/g DES was achieved by [Im][NO3]/EG with molar ratio of 1:3, and was higher than all the reported ILs and IL‐based DESs, which was originated from multiple hydrogen bonding between acidic H and hydroxyl groups of the DESs and NH3. This work will provide useful idea for designing IL‐based solvents for NH3 separation applications.

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  • 33.
    Liu, Yanrong
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Li, Fangfang
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Zhang, Xiangping
    CAS Key Laboratory of Green Process and Engineering, Beijing Key Laboratory of Ionic Liquids Clean Process, State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, 100190, Beijing, PR China. Zhengzhou Institute of Emerging Industrial Technology, 450000, Zhengzhou, PR China. Dalian National Laboratory for Clean Energy, Dalian, 116023, China.
    Ji, Xiaoyan
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Recent progress on electrochemical reduction of CO2 to methanol2020Ingår i: Current Opinion in Green and Sustainable Chemistry, ISSN 2452-2236, Vol. 23, s. 10-17Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    Methanol is a future energy carrier because of its high volume-specific energy density and a significant intermediate for many bulk chemicals. Electrochemical reduction (ECR) is a promising method to fabricate methanol (CH3OH) from carbon dioxide (CO2) where electrocatalyst, reactor configuration and electrode play an essential role. In this review, seven types of electrocatalysts, i.e., metal alloys, metal oxides, metal chalcogenides and carbides, metal-organic complexes, metal-free, pyridine and MOF-based electrocatalyts, as well as the effect of reactor configuration and electrode were comprehensively summarized. Finally, challenges and perspectives on developing electrocatalysts were highlighted.

  • 34.
    Liu, Yanrong
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Yu, Hang
    State Key Laboratory of Material-Oriented Chemical Engineering, Nanjing Tech University, Nanjing, China.
    Sun, Yunhao
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Zeng, Shaojuan
    CAS Key Laboratory of Green Process and Engineering, Beijing Key Laboratory of Ionic Liquids Clean Process, State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, China.
    Zhang, Xiangping
    CAS Key Laboratory of Green Process and Engineering, Beijing Key Laboratory of Ionic Liquids Clean Process, State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, China. Zhengzhou Institute of Emerging Industrial Technology, Zhengzhou, China.
    Nie, Yi
    CAS Key Laboratory of Green Process and Engineering, Beijing Key Laboratory of Ionic Liquids Clean Process, State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, China. Zhengzhou Institute of Emerging Industrial Technology, Zhengzhou, China.
    Zhang, Suojiang
    CAS Key Laboratory of Green Process and Engineering, Beijing Key Laboratory of Ionic Liquids Clean Process, State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, China. School of Chemical Engineering, University of Chinese Academy of Sciences, Beijing, China.
    Ji, Xiaoyan
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Screening Deep Eutectic Solvents for CO2 Capture With COSMO-RS2020Ingår i: Frontiers in Chemistry, E-ISSN 2296-2646, Vol. 8, nr 82Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this work, 502 experimental data for CO2 solubilities and 132 for Henry’s constantsof CO2 in DESs were comprehensively summarized from literatures and used for furtherverification and development of COSMO-RS. Large systematic deviations of 62.2, 59.6,63.0, and 59.1% for the logarithmic CO2 solubilities in the DESs (1:2, 1:3, 1:4, 1:5),respectively, were observed for the prediction with the original COSMO-RS, while thepredicted Henry’s constants of CO2 in the DESs (1:1.5, 1:2, 1:3, 1:4, 1:5) at temperaturesranging of 293.15–333.15 K are more accurate than the predicted CO2 solubility withthe original COSMO-RS. To improve the performance of COSMO-RS, 502 data pointsof CO2 solubility in the DESs (1:2, 1:3, 1:4, 1:5) were used for correcting COSMO-RSwith a temperature-pressure dependent parameter, and the CO2 solubility in the DES(1:6) was predicted to further verify the performance of the corrected model. The resultsindicate that the corrected COSMO-RS can significantly improve the model performancewith the ARDs decreasing down to 6.5, 4.8, 6.5, and 4.5% for the DESs (1:2, 1:3, 1:4, and 1:5), respectively, and the corrected COSMO-RS with the universal parameters can beused to predict the CO2 solubility in DESs with different mole ratios, for example, for theDES (1:6), the corrected COSMO-RS significantly improves the prediction with an ARD of10.3% that is much lower than 78.2% provided by the original COSMO-RS. Additionally,the result from COSMO-RS shows that the σ-profiles can reflect the strength of molecularinteractions between an HBA (or HBD) and CO2, determining the CO2 solubility, and thedominant interactions for CO2 capture in DESs are the H-bond and Van der Waals force,followed by the misfit based on the analysis of the predicted excess enthalpies.

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  • 35.
    Zhou, Le
    et al.
    CAS Key Laboratory of Green Process and Engineering, Beijing Key Laboratory of Ionic Liquids Clean Process, State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China. School of Chemical Engineering, University of Chinese Academy of Sciences, Beijing 100049, China. Zhengzhou Institute of Emerging Industrial Technology, Zhengzhou 450000, China.
    Pan, Fengjiao
    CAS Key Laboratory of Green Process and Engineering, Beijing Key Laboratory of Ionic Liquids Clean Process, State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China. School of Chemical Engineering, University of Chinese Academy of Sciences, Beijing 100049, China. Zhengzhou Institute of Emerging Industrial Technology, Zhengzhou 450000, China.
    Liu, Yanrong
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Kang, Zhaoqing
    CAS Key Laboratory of Green Process and Engineering, Beijing Key Laboratory of Ionic Liquids Clean Process, State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China.
    Zeng, Shaojuan
    CAS Key Laboratory of Green Process and Engineering, Beijing Key Laboratory of Ionic Liquids Clean Process, State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China.
    Nie, Yi
    CAS Key Laboratory of Green Process and Engineering, Beijing Key Laboratory of Ionic Liquids Clean Process, State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China. School of Chemical Engineering, University of Chinese Academy of Sciences, Beijing 100049, China. Zhengzhou Institute of Emerging Industrial Technology, Zhengzhou 450000, China.
    Study on the regularity of cellulose degradation in ionic liquids2020Ingår i: Journal of Molecular Liquids, ISSN 0167-7322, E-ISSN 1873-3166, Vol. 308, artikel-id 113153Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Ionic liquids (ILs) show the superiority in dissolving and spinning of cellulose. In this work, wood pulp and microcrystalline cellulose were dissolved respectively in two ILs, 1-allyl-3-methylimidazolium chloride ([Amim]Cl) and 1-ethyl-3-methylimidazolium diethyl phosphate ([Emim]DEP), to investigate the regularity of cellulose degradation in ILs. A novel method for determining degree of polymerization of cellulose employed ILs was proposed and its accuracy was compared with the traditional method. The results indicated that cellulose depolymerized seriously with the increase of time and temperature in [Amim]Cl than in [Emim]DEP. In addition, after cellulose dissolving for 72 h, none of the reducing sugar remained in the recycled [Emim]DEP, however, more than 2% reducing sugar can be measured in the recycled [Amim]Cl. These results are consistent with FT-IR investigation, i.e., [Amim]Cl shows greater dissolution capability for cellulose than [Emim]DEP. Therefore, [Emim]DEP shows great prospects in the continuous industrial spinning process under the determined temperature of 90–100 °C.

  • 36.
    Falk, Joel
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Skoglund, Nils
    Thermochemical Energy Conversion Laboratory, Department of Applied Physics and Electronics, Umeå University, Umeå, Sweden.
    Grimm, Alejandro
    Department of Forest Biomaterials and Technology, Swedish University of Agricultural Sciences, Umeå, Sweden.
    Öhman, Marcus
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Systematic Evaluation of the Fate of Phosphorus in Fluidized Bed Combustion of Biomass and Sewage Sludge2020Ingår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 34, nr 4, s. 3984-3995Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    Comprehensive knowledge concerning the behavior of phosphorus (P) during combustion is necessary to enable more efficient recovery of P from combustion ashes for agricultural purposes. To this end, parameters that influence the distribution and speciation of P in combustion ashes are important because they may influence which ash fractions are suitable for P recovery. This study aims to determine the fate of P as a result of fuel ash composition and chemical association in the fuel during fluidized bed combustion by a systemic review of previous work. The synthesis was performed by comparing scanning electron microscopy–energy-dispersive X-ray spectroscopy and X-ray diffraction chemical analyses of bed ash, fly ash particles, and deposits from fluidized bed combustion of different blends of P-poor (logging residues or wheat straw) and P-rich (sewage sludge, dried distiller’s grain with solubles, or phosphoric acid) fuels and additives. The blends were produced to have a similar ash composition but with a different P source. The distribution of P among ash fractions indicated that P is mainly found in the coarse ash fractions (bed and cyclone ash), irrespective of fuel ash composition or chemical association in the fuel. The chemical speciation of P in coarse ash fractions differed between biomass blends containing sewage sludge compared to blends with phosphoric acid or dried distiller’s grain with solubles. Phosphates in the ash from the two sewage sludge blends included predominantly Ca with minor inclusion of other cations. In contrast, ashes from the blends with phosphoric acid or dried distiller’s grain with solubles contained phosphates with a significant amount of K, Ca, and Mg. The difference in phosphate speciation could not solely be explained by the combustion conditions and the elemental composition of the ash fractions. These results show that it is necessary to consider the chemical association of P in the fuel to predict the type of phosphates that will form in fluidized bed combustion ashes.

  • 37.
    Pericault, Youen
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Arkitektur och vatten.
    Risberg, Mikael
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Viklander, Maria
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Arkitektur och vatten.
    Hedström, Annelie
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Arkitektur och vatten.
    Temperature performance of a heat-traced utilidor for sewer and water pipes in seasonally frozen ground2020Ingår i: Tunnelling and Underground Space Technology, ISSN 0886-7798, E-ISSN 1878-4364, Vol. 97, artikel-id 103261Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Heat-traced utility corridors (utilidors) can be used in cold regions to install the drinking water and sewer pipes in a shallow trench above the frost depth, thereby limiting excavation needs and the associated economic, social, and environmental costs. Several of these infrastructures were built in the 60s and 70s in Canada, Alaska, Russia, and Norway. More recently, a new type of heat-traced utilidor was built as a pilot project in Kiruna, Sweden to increase the viability of district heating in the area by allowing co-location of all the utility pipes in a shallow trench. Despite several reported cases of undesirably warm drinking water from full-scale projects, previous research efforts on heat-traced utilidors have mainly focused on pipe freeze protection, not on the prevention of excessive temperatures of the drinking water. To ensure comfortable drinking water in terms of taste and smell, an upper temperature limit of 15 °C is usually recommended. The objective of this study was to evaluate the long-term ability of a heat-traced utilidor to maintain sewer temperatures above 0 °C and drinking water temperatures between 0 and 15 °C. Pipe temperatures were measured continuously at two cross sections of a heat-traced utilidor located in Northern Sweden over a period of 22 months. A thermal model, set up and calibrated on the measurements, was used to simulate the impact of extraordinary cold weather conditions on the pipes’ temperatures. The results showed that the utilidor could keep the pipe temperatures within the desired ranges in most cases but that special care should be taken during design to limit drinking water temperatures during the summer.

  • 38.
    Sefidari, Hamid
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap. Luossavaara-Kiirunavaara Aktiebolag (LKAB), Luleå, Sweden.
    Ma, C.
    Department of Applied Physics and Electronics, Thermochemical Energy Conversion Laboratory, Umeå University, Umeå, Sweden.
    Fredriksson, C.
    Luossavaara-Kiirunavaara Aktiebolag (LKAB), Luleå, Sweden.
    Lindblom, Bo
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap. Luossavaara-Kiirunavaara Aktiebolag (LKAB), Luleå, Sweden.
    Wiinikka, Henrik
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap. RISE ETC (Energy Technology Centre) AB, Piteå, Sweden.
    Nordin, L.O
    Luossavaara-Kiirunavaara Aktiebolag (LKAB), Luleå, Sweden.
    Wu, G.
    GTT Technologies, Herzogenrath,Germany. Institute of Energy and Climate Research, Microstructure and Properties of Materials (IEK-2), Forschungszentrum Jülich GmbH, Germany.
    Yazhenskikh, E.
    Institute of Energy and Climate Research, Microstructure and Properties of Materials (IEK-2), Forschungszentrum Jülich GmbH, Germany.
    Müller, M.
    Institute of Energy and Climate Research, Microstructure and Properties of Materials (IEK-2), Forschungszentrum Jülich GmbH, Germany.
    Öhman, Marcus
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    The effect of co-firing coal and woody biomass upon the slagging/deposition tendency in iron-ore pelletizing grate-kiln plants2020Ingår i: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 199, artikel-id 106254Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Woody biomass is being considered a potential co-firing fuel to reduce coal consumption in iron-ore pelletizing rotary kilns. An important consideration is the slagging inside the kiln caused by ash deposition that can lead to process disturbances or shutdowns. In terms of ash chemistry, co-firing woody biomass implies the addition of mainly Ca and K to the Si- and Al-dominated coal-ash (characteristic of high-rank coals) and Fe from the iron-ore that are both inherent to the process. An alkali-laden gaseous atmosphere is also present due to the accumulation of alkali via the recirculation of flue gas in the system. The slagging propensity of blending woody biomass with coal in the grate-kiln process was studied based on the viscosity of the molten phases predicted by global thermochemical equilibrium modeling. This was carried out for variations in temperature, gaseous KOH atmosphere, and fuel blending levels. Results were evaluated and compared using a qualitative slagging indicator previously proposed by the authors where an inverse relationship between deposition tendency and the viscosity of the molten fraction of the ash was established. The results were also compared with a set of co-firing experiments performed in a pilot-scale (0.4 MW) experimental combustion furnace. In general, the co-firing of woody biomass would likely increase the slagging tendency via the increased formation of low-viscosity melts. The fluxing behavior of biomass-ash potentially reduces the viscosity of the Fe-rich aluminosilicate melt and intensifies deposition. However, the results also revealed that there are certain conditions where deposition tendency may decrease via the formation of high-melting-point alkali-containing solid phases (e.g., leucite).© 2019 Elsevier

  • 39.
    Lundqvist, Petter
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Risberg, Mikael
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Westerlund, Lars
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    The importance of adjusting the heating system after an energy-retrofit of buildings in a sub-Arctic climate2020Ingår i: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 217, artikel-id 109969Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    There is a need to improve the understanding and the knowledge of energy efficiency measures for residential buildings in sub-Arctic climate regions. This paper presents an investigation of two identical multi-family residential buildings in the sub-Arctic climate of northern Sweden, before and after renovation. During the renovation, additional insulation of the external walls and new windows were installed in one building, while the other building retained its original envelope.

    The energy usage data for the past four heating seasons were collected, including data from before and after the renovation. Detailed thermal indoor climate data were gathered for specific months. The data from the two separate buildings showed that the renovation did not result in a significant improvement in energy usage. Prior to the renovation, the energy usage data showed a difference of 2-3% in the heat supply between the two buildings, and this difference persisted after the renovation. On the other hand, the indoor air temperature was raised. The renovated building had an indoor air temperature which was 2°C higher than the not yet renovated building.

    IDA ICE models were constructed and validated with the measured data to investigate how a lower indoor air temperature would affect the energy usage and indoor thermal climate. The models showed that with a reduction in the indoor air temperature by 2°C after the renovation, the thermal climate would maintain an acceptable level according to PMV/PPD standards, and would result in a 13-14% reduction of the heat supply during the cold months. With an annual reduction of 15%, the heat supply could be reduced by 270 MWh per year for the whole area where the buildings are located. This clearly demonstrates the importance of adjusting the heating system after an energy efficiency measure has been performed.

  • 40.
    Chen, Yifeng
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap. Key Laboratory of Material and Chemical Engineering, Nanjing Tech University, Nanjing, China.
    Ma, Chunyan
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap. Key Laboratory of Material and Chemical Engineering, Nanjing Tech University, Nanjing, China.
    Ji, Xiaoyan
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Yang, Zhuhong
    Key Laboratory of Material and Chemical Engineering, Nanjing Tech University, Nanjing, China.
    Lu, Xiaohua
    Key Laboratory of Material and Chemical Engineering, Nanjing Tech University, Nanjing, China.
    Thermodynamic study on aqueous polyethylene glycol 200 solution and performance assessment for CO2 separation2020Ingår i: Fluid Phase Equilibria, ISSN 0378-3812, E-ISSN 1879-0224, Vol. 504, artikel-id 112336Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    To develop polyethylene glycol 200 (PEG200) and aqueous PEG200 solutions (PEG200/H2O) as solvents for CO2 separation, in this study, the available thermo-physical properties of PEG200 and PEG200/H2O measured experimentally were surveyed, evaluated, and correlated with empirical equations. The solubility of CO2 in PEG200 was also surveyed, evaluated and described with the Henry's law with the Poynting correction, while the solubilities of CH4 and N2 in PEG200 were determined experimentally and then described with the Henry's law. The CO2, CH4 and N2 solubilities in PEG200/H2O were measured and described with the Redlich–Kwong Nonrandom-Two-Liquid (RK-NRTL) model. In addition, the performances of PEG200, PEG200/H2O and other commercialized physical solvents for CO2 separation were discussed based on the properties, and the biogas upgrading was chosen as the example to quantitatively evaluate the performances of PEG200 and PEG200/H2O with process simulation and compared with the high pressure water scrubbing (HPWS). It shows that the total energy usage and the amount of recirculated solvent for biogas upgrading can decrease by 9.1% and 26.5%, respectively, when H2O is replaced by PEG200 completely.

  • 41.
    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.
    Towards Optimal Sustainable Energy Systems in Nordic Municipalities2020Ingår i: Energies, ISSN 1996-1073, E-ISSN 1996-1073, Vol. 13, nr 2, artikel-id 290Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Municipal energy systems in the northern regions of Finland, Norway, and Sweden facemultiple challenges: large-scale industries, cold climate, and a high share of electric heatingcharacterize energy consumption and cause significant peak electricity demand. Local authoritiesare committed in contributing to national goals on CO2 emission reductions by improving energyefficiency and investing in local renewable electricity generation, while considering their ownobjectives for economic development, increased energy self-sufficiency, and affordable energy costs.This paper formulates a multi-objective optimization problem about these goals that is solved byinterfacing the energy systems simulation tool EnergyPLAN with a multi-objective evolutionaryalgorithm implemented in Matlab. A sensitivity analysis on some key economic parameters is alsoperformed. In this way, optimal alternatives are identified for the integrated electricity and heatingsectors and valuable insights are offered to decision-makers in local authorities. Piteå (Norrbotten,Sweden) is used as a case study that is representative of Nordic municipalities, and results showthat CO2 emissions can be reduced by 60% without a considerable increase in total costs and thatpeak electricity import can be reduced by a maximum of 38%.

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  • 42.
    Andersson, Linda
    et al.
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Samhällsvetenskap.
    Ek, Kristina
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Samhällsvetenskap.
    Kastensson, Åsa
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Wårell, Linda
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Samhällsvetenskap.
    Transition towards sustainable transportation: What determines fuel choice?2020Ingår i: Transport Policy, ISSN 0967-070X, E-ISSN 1879-310X, Vol. 90, s. 31-38Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    For the transport sector to become more sustainable, substantial technological and behavioural changes are required. Increased understanding about household choices related to more green alternatives in transportation is needed in order for policy makers to make efficient policies in the future. The main purpose of this paper is to analyze which factors that determines the fuel choice between ethanol and gasoline for owners of flex-fuel vehicles (FFVs). We evaluate how the self-reported fuel choice is influenced by the relative price, as well as individual differences in norms and perceptions about environmental and quality attributes of ethanol. Data was collected through a survey sent to Swedish FFV owners and is analyzed in a binary choice and a LCM framework. Results show that price, perceptions about quality, age and environmental attitudes influence the self-reported willingness to choose ethanol. Furthermore, results show that preferences are not homogenous, three groups are identified; price conscious respondents, ethanol skeptical respondents and respondents with pronounced environmental concern. However, although the motive for introducing and subsidizing ethanol was to reduce climate and environmental impacts, the group that chooses ethanol based on climate and environmental motives is small. The results further reveal that the debate about motor damages from ethanol have had a long lasting effect on the willingness to choose ethanol. Thus, it is necessary to try to prevent or mitigate concerns regarding e.g. potential technical or ethical issues when promoting future technologies or fuels aimed at a sustainable transportation sector.

  • 43.
    Pan, Fengjiao
    et al.
    Beijing Key Laboratory of Ionic Liquids Clean Process, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, China. School of Chemical Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China. Zhengzhou Institute of Emerging Industrial Technology, Zhengzhou, 450000, China.
    Zhou, Le
    Beijing Key Laboratory of Ionic Liquids Clean Process, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, China. School of Chemical Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China. Zhengzhou Institute of Emerging Industrial Technology, Zhengzhou, 450000, China.
    Zeng, Shaojuan
    Beijing Key Laboratory of Ionic Liquids Clean Process, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, China.
    Liu, Xue
    Beijing Key Laboratory of Ionic Liquids Clean Process, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, China.
    Liu, Yanrong
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Nie, Yi
    Beijing Key Laboratory of Ionic Liquids Clean Process, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, China. School of Chemical Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China. Zhengzhou Institute of Emerging Industrial Technology, Zhengzhou, 450000, China.
    离子液体/羊毛纤维/凝固剂三元相图的构建2020Ingår i: The Chinese Journal of Process Engineering, ISSN 1009-606XArtikel i tidskrift (Refereegranskat)
    Abstract [zh]

    三元相图是研究羊毛角蛋白再生过程热力学行为的有效工具。通过浊度测试和 Boom 经验方程构建离子液体(IL)/羊毛 纤维/凝固剂浊点线性关系(LCP)曲线和三元相图,进一步系统地研究了凝固剂种类、再生温度和离子液体结构对羊毛角蛋白再 生性能的影响规律。结果表明,羊毛角蛋白最优再生体系是 1-乙基-3-甲基咪唑磷酸二乙酯([Emim]Dep)/羊毛纤维/水(25 ℃)。对 羊毛纤维原料和不同再生条件获得的再生羊毛角蛋白进行 FTIR 和 XRD 表征,结果表明再生羊毛角蛋白的结构和羊毛纤维原料 基本保持一致,但相对结晶度有所下降。实验温度为 25 ℃,以水为凝固剂制备的再生羊毛角蛋白相对结晶度最高。

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  • 44.
    Sandberg, Erik
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Toffolo, Andrea
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Krook-Riekkola, Anna
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    A bottom-up study of biomass and electricity use in a fossil free Swedish industry2019Ingår i: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 167, s. 1019-1030Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    While previous research has focused on single industrial sectors or specific technologies, this study aims to explore the impacts of various industrial technology options on the use of biomass and electricity in a future fossil free Swedish industry. By building a small optimization model, that decomposes each industrial sector into site categories by type and technology to capture critical synergies among industrial processes. The results show important synergies between electrification, biomass and CCS/U (sequestration of CO2 is required to reach net-zero emissions). Reaching an absolute minimum of biomass use within the industry has a very high cost of electricity due to the extensive use of power-to-gas technologies, and minimising electricity has a high cost of biomass due to extensive use of CHP technologies. Meanwhile, integrated bio-refinery processes are the preferable option when minimising the net input of energy. There is, thus, no singular best technology, instead the system adapts to the given circumstances showing the importance of a detailed bottom-up modelling approach and that the decarbonisation of the industry should not be treated as a site-specific problem, but rather as a system-wide problem to allow for optimal utilisation of process synergies.

  • 45.
    Schmidt, Johannes
    et al.
    Institute for Sustainable Economic Development, University of Natural Resources and Life Sciences, Vienna, Austria.
    Gruber, Katharina
    Institute for Sustainable Economic Development, University of Natural Resources and Life Sciences, Vienna, Austria.
    Klingler, Michael
    Institute for Sustainable Economic Development, University of Natural Resources and Life Sciences, Vienna, Austria.Department of Geography, University of Innsbruck, Austria.
    Klöckl, Claude
    Institute for Sustainable Economic Development, University of Natural Resources and Life Sciences, Vienna, Austria.
    Camargo, Luis Ramirez
    Institute for Sustainable Economic Development, University of Natural Resources and Life Sciences, Vienna, Austria.International Institute for Applied Systems Analysis (IIASA), Laxenburg, Austria.
    Regner, Peter
    Institute for Sustainable Economic Development, University of Natural Resources and Life Sciences, Vienna, Austria.
    Turkovska, Olga
    Institute for Sustainable Economic Development, University of Natural Resources and Life Sciences, Vienna, Austria.
    Wehrle, Sebastian
    Institute for Sustainable Economic Development, University of Natural Resources and Life Sciences, Vienna, Austria.
    Wetterlund, Elisabeth
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap. International Institute for Applied Systems Analysis (IIASA), Laxenburg, Austria.
    A new perspective on global renewable energy systems: why trade in energy carriers matters2019Ingår i: Energy & Environmental Science, ISSN 1754-5692, E-ISSN 1754-5706, Vol. 12, nr 7, s. 2022-2029Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Recent global modelling studies suggest a decline of long-distance trade in energy carriers in future global renewable energy systems, compared to today's fossil fuel based system. In contrast, we identify four drivers that facilitate trade of renewable energy carriers. These drivers may lead to trade volumes remaining at current levels or even to an increase during the transition to an energy system with very high shares of renewables. First, new land-efficient technologies for renewable fuel production become increasingly available and technically allow for long-distance trade in renewables. Second, regional differences in social acceptance and land availability for energy infrastructure support the development of renewable fuel import and export streams. Third, the economics of renewable energy systems, i.e. the different production conditions globally and the high costs of fully renewable regional electricity systems, will create opportunities for spatial arbitrage. Fourth, a reduction of stranded investments in the fossil fuel sector is possible by switching from fossil fuels to renewable fuel trade. The impact of these drivers on trade in renewable energy carriers is currently under-investigated by the global energy systems research community. The importance of the topic, in particular as trade can redistribute profits and losses of decarbonization and may hence support finding new partners in climate change mitigation negotiations, warrants further research efforts in this area therefore.

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  • 46.
    Toffolo, Andrea
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Lazzaretto, A.
    University of Padova, Padova, Italy.