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  • 1.
    Ahlström, Johan M.
    et al.
    Chalmers University of Technology, Dep. of Space, Earth and Environment, Div. of Energy Technology.
    Pettersson, Karin
    Chalmers University of Technology, Dep. of Space, Earth and Environment, Div. of Energy Technology; RISE Research Institute of Sweden.
    Wetterlund, Elisabeth
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Harvey, Simon
    Chalmers University of Technology, Dep. of Space, Earth and Environment, Div. of Energy Technology.
    Value chains for integrated production of liquefied bio-SNG at sawmill sites: Techno-economic and carbon footprint evaluation2017Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 206, s. 1590-1608Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Industry’s increasing demand for liquefied natural gas could be met in the future by liquefied methane produced from biomass feedstock (LBG - liquefied biogas). This study presents results from an investigation of value chains for integrated production of LBG at a generic sawmill site, based on gasification of sawmill waste streams and forest residues. The objective was to investigate the cost for, as well as the carbon footprint reduction associated with, production and use of LBG as a fuel. Five different LBG plant sizes were investigated in combination with three different sawmill sizes. The resulting cases differ regarding biomass feedstock composition, biomass transportation distances, LBG plant sizes, how efficiently the excess heat from the LBG plant is used, and LBG distribution distances. Pinch technology was used to quantify the heat integration opportunities and to design the process steam network. The results show that efficient use of energy within the integrated process has the largest impact on the performance of the value chain in terms of carbon footprint. The fuel production cost are mainly determined by the investment cost of the plant, as well as feedstock transportation costs, which mainly affects larger plants. Production costs are shown to range from 68 to 156 EUR/MW hfuel and the carbon footprint ranges from 175 to 250 kg GHG-eq/MW hnet biomass assuming that the product is used to substitute fossil LNG fuel. The results indicate that process integration of an indirect biomass gasifier for LBG production is an effective way for a sawmill to utilize its by-products. Integration of this type of biorefinery can be done in such a way that the plant can still cover its heating needs whilst expanding its product portfolio in a competitive way, both from a carbon footprint and cost perspective. The results also indicate that the gains associated with efficient heat integration are important to achieve an efficient value chain.

  • 2.
    Akhtar, Farid
    et al.
    Department of Materials and Environmental Chemistry, Berzelii Center EXSELENT on Porous Materials, Stockholm University.
    Andersson, Linnéa
    Department of Materials and Environmental Chemistry, Berzelii Center EXSELENT on Porous Materials, Stockholm University.
    Keshavarzi, Neda
    Department of Materials and Environmental Chemistry, Berzelii Center EXSELENT on Porous Materials, Stockholm University.
    Bergström, Lennart
    Department of Materials and Environmental Chemistry, Berzelii Center EXSELENT on Porous Materials, Stockholm University.
    Colloidal processing and CO 2 capture performance of sacrificially templated zeolite monoliths2012Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 97, s. 289-296Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Sacrificial templating of suspension cast and subsequently thermally treated zeolite monoliths with glassy carbon spheres and fibers yielded zeolite 13X and silicalite-1 monoliths with macroporosities up to 50 vol%. Homogeneous distribution of the macroporosity in hierarchically porous monoliths was obtained by tailoring the surface chemistry of the carbon particles by polyelectrolyte-assisted adsorption of zeolite particles. The effect of amount of kaolin binder and temperature for the thermal treatment on the monoliths strength, surface area and CO2 uptake was studied by diametral compression tests, electron microscopy, X-ray diffraction and gas adsorption. Cyclic adsorption and regeneration measurements showed that zeolite 13X monoliths display a high CO2 uptake while the silicalite-1 monoliths could be regenerated with a relatively low energy penalty.

  • 3.
    Andersson, Jan-Olof
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Elfgren, Erik
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Westerlund, Lars
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Improved energy efficiency in juice production through waste heat recycling2014Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 130, nr S1, s. 757-763Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Berry juice concentrate is produced by pressing berries and heating up the juice. The by-products are berry skins and seeds in a press cake. Traditionally, these by-products have been composted, but due to their valuable nutrients, it could be profitable to sell them instead. The skins and seeds need to be separated and dried to a moisture content of less than 10 %wt (on dry basis) in order to avoid fermentation. A berry juice plant in the north of Sweden has been studied in order to increase the energy and resource efficiency, with special focus on the drying system. This was done by means of process integration with mass and energy balance, theory from thermodynamics and psychrometry along with measurements of the juice plant. Our study indicates that the drying system could be operated at full capacity without any external heat supply using waste heat supplied from the juice plant. This would be achieved by increasing the efficiency of the dryer by recirculation of the drying air and by heat supply from the flue gases of the industrial boiler. The recirculation would decrease the need of heat in the dryer with about 52%. The total heat use for the plant could thereby be decreased from 1262 kW to 1145 kW. The improvements could be done without compromising the production quality.

  • 4.
    Andersson, Jan-Olof
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Toffolo, Andrea
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Improving energy efficiency of sawmill industrial sites by integration with pellet and CHP plants2013Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 111, s. 791-800Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    An essential strategy to lower energy and resources consumption is the development of highly integrated industrial sites including different kind of plants complementing one another. Sawmills are huge biomass suppliers to other industries, such as pulp and paper mills, pellet plants and CHP plants, and part of the biomass is also used for the internal heat requirement. In this paper the integration of a sawmill with a pellet plant and a CHP plant is investigated using advanced process integration techniques, so that the thermal energy and the electricity produced in the CHP plant by burning part of the sawmill biomass output are used for the heat and power requirements of the other two industries. The results show that up to 18% of the biomass by-products from the sawmill can be saved, but from the economic point of view the ratio between prices of the thermal energy sold for district heating and the low quality biomass has to be lower than the present one to make the integrated design solution more attractive than separate plant operation.

  • 5.
    Andersson, Jan-Olof
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Westerlund, Lars
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Improved energy efficiency in sawmill drying system2014Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 113, s. 891-901Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The worldwide use of biomass has increased drastically during the last decade. At Swedish sawmills about half of the entering timber becomes lumber, with the remainder considered as by-product (biomass). A significant part of this biomass is used for internal heat production, mainly for forced drying of lumber in drying kilns. Large heat losses in kilns arise due to difficulties in recovering evaporative heat in moist air at low temperatures. This paper addresses the impact of available state-of-the-art technologies of heat recycling on the most common drying schemes used in Swedish sawmills. Simulations of different technologies were performed on an hourly basis to compare the heat and electricity demand with the different technologies. This was executed for a total sawmill and finally to the national level to assess the potential effects upon energy efficiency and biomass consumption. Since some techniques produce a surplus of heat the comparison has to include the whole sawmill. The impact on a national level shows the potential of the different investigated techniques. The results show that if air heat exchangers were introduced across all sawmills in Sweden, the heat demand would decrease by 0.3 TWh/year. The mechanical heat pump technology would decrease the heat demand by 5.6 TWh/year and would also produce a surplus for external heat sinks, though electricity demand would increase by 1 TWh/year. The open absorption system decreases the heat demand by 3.4 TWh/year on a national level, though at the same time there is a moderate increase in electricity demand of 0.05 TWh/year. Introducing actual energy prices in Sweden gives an annual profit (investment cost excluded) on national level for the open absorption system of almost 580 million SEK. For the mechanical heat pump technology the profit is 204 million SEK and for the traditional heat exchanger the profit is significant lower. It has been found that a widespread implementation of available energy recovery technologies across Swedish sawmills would result in substantial savings of biomass for other purposes in the society

  • 6.
    Andersson, Jan-Olof
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Westerlund, Lars
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Surplus biomass through energy efficient kilns2011Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 88, nr 12, s. 4848-4853Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The use of biomass in the European Union has increased since the middle of the 1990s, mostly because of high subsidies and CO2 emission regulation through the Kyoto protocol. The sawmills are huge biomass suppliers to the market; out of the Swedish annual lumber production of 16.4 Mm3, 95% is produced by medium to large-volume sawmills with a lumber quotient of 47%. The remaining part is produced as biomass. An essential part (12%) of the entering timber is used for supply of heat in their production processes, mostly in the substantial drying process. The drying process is the most time and heat consuming process in the sawmill. This study was undertaken to determine the sawmills’ national use of energy and potential magnitude of improvements. If the drying process can be made more effective, sawmills’ own use of biomass can be decreased and allow a considerably larger supply to the biomass market through processed or unprocessed biomass, heat or electricity production. The national electricity and heat usage when drying the lumber have been analysed by theoretical evaluation and experimental validation at a batch kiln. The main conclusion is that the heat consumption for drying lumber among the Swedish sawmills is 4.9 TW h/year, and with available state-of-the-art techniques it is possible to decrease the national heat consumption by approximately 2.9 TW h. This additional amount of energy corresponds to the market’s desire for larger energy supply.

  • 7.
    Andersson, Jim
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Lundgren, Joakim
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Techno-economic analysis of ammonia production via integrated biomass gasification2014Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 130, nr S1, s. 484-490Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Ammonia (NH3) can be produced by synthesis of nitrogen and hydrogen in the Haber–Bosch process, where the economic challenge is the hydrogen production. Currently, substantial amounts of greenhouse gases are emitted from the ammonia industry since the hydrogen production is almost exclusively based on fossil feedstocks. Hydrogen produced via gasification of lignocellulosic biomass is a more environmentally friendly alternative, but the economic performance is critical. The main objective of this work was to perform a techno-economic evaluation of ammonia production via integrated biomass gasification in an existing pulp and paper mill. The results were compared with a stand-alone production case to find potential technical and economic benefits deriving from the integration. The biomass gasifier and the subsequent NH3 production were modelled using the commercial software Aspen Plus. A process integration model based on Mixed Integer Linear Programming (MILP) was used to analyze the effects on the overall energy system of the pulp mill. Important modelling constraints were to maintain the pulp production and the steam balance of the mill. The results showed that the process economics and energy performance are favourable for the integrated case compared to stand-alone production. The main conclusion was however that a rather high NH3 selling price is required to make both production cases economically feasible.

  • 8.
    Babler, Matthaus U.
    et al.
    Department Chemical Engineering and Technology, KTH Royal Institute of Technology.
    Phounglamcheik, Aekjuthon
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Amovic, Marko
    Cortus Energy AB.
    Ljunggren, Rolf
    Cortus Energy AB.
    Engvall, Klas
    Department Chemical Engineering and Technology, KTH Royal Institute of Technology.
    Modeling and pilot plant runs of slow biomass pyrolysis in a rotary kiln2017Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 207, s. 123-133Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Pyrolysis of biomass in a rotary kiln finds application both as an intermediate step in multistage gasification as well as a process on its own for the production of biochar. In this work, a numerical model for pyrolysis of lignocellulosic biomass in a rotary kiln is developed. The model is based on a set of conservation equations for mass and energy, combined with independent submodels for the pyrolysis reaction, heat transfer, and granular flow inside the kiln. The pyrolysis reaction is described by a two-step mechanism where biomass decays into gas, char, and tar that subsequently undergo further reactions; the heat transfer model accounts for conduction, convection and radiation inside the kiln; and the granular flow model is described by the well known Saeman model. The model is compared to experimental data obtained from a pilot scale rotary kiln pyrolyzer. In total 9 pilot plant trials at different feed flow rate and different heat supply were run. For moderate heat supplies we found good agreement between the model and the experiments while deviations were seen at high heat supply. Using the model to simulate various operation conditions reveals a strong interplay between heat transfer and granular flow which both are controlled by the kiln rotation speed. Also, the model indicates the importance of heat losses and lays the foundation for scale up calculations and process optimization.

  • 9.
    Bach-Oller, Albert
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Furusjö, Erik
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap. RISE Bioeconomy, Stockholm, Sweden.
    Umeki, Kentaro
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    On the role of potassium as a tar and soot inhibitor in biomass gasification2019Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 254, artikel-id 113488Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The work investigates in a drop tube furnace the effect of potassium on carbon conversion for three different types of fuels: an ash lean stemwood, a calcium-rich bark and a silicon-rich straw. The study focuses on an optimal method for impregnating the biomass with potassium. The experiments are conducted for 3 different impregnation methods; wet impregnation, spray impregnation, and dry mixing to investigate different levels of contact between the fuel and the potassium. Potassium is found to catalyse both homogenous and heterogeneous reactions. All the impregnation methods showed a significant effect of potassium on heterogeneous reactions (char conversion). The fact that dry mixing of potassium in the biomass shows an effect reveals the existence of a gas-induced mechanism that supply and distributes potassium on the char particles. Concerning the effect of potassium on homogenous reactions, it is found that potassium in the gas phase leads to much lower yields of C2 hydrocarbons, heavy tars and soot. The results indicate that potassium reduces the likelihood of light aromatic to progress toward heavier polyaromatic hydrocarbons clusters, thereby inhibiting the formation of soot-like material. A moderate interaction between the added potassium and the inherent ash forming elements is also observed: Potassium has a smaller effect when the fuel is naturally rich in silicon. The combined results are of interest for the design of a gasification process that incorporates recirculation of naturally occurring potassium to improve entrained flow gasification of biomass.

  • 10.
    Biswas, Amit
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Rudolfsson, Magnus
    Swedish University of Agricultural Sciences, Unit of Biomass Technology and Chemistry, Umeå.
    Broström, Markus
    Umeå University. Department of Applied Physics and Electronics.
    Umeki, Kentaro
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Effect of pelletizing conditions on combustion behaviour of single wood pellet2014Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 119, s. 79-84Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper presents how pelletizing die temperature and moisture content affect combustion behaviour of single wood pellet. Pine wood particles with two different moisture contents (i.e. 1 wt.% and 12 wt.%) were pelletized in a laboratory-scale single pelletizer (single die pellets) at die temperature of 20, 100, 150 and 200 °C. The pellets were combusted in a laboratory scale furnace at 800 °C. Time required for single pellet combustion generally increased with both increase of pelletizing temperature and moisture content of biomass. In addition, combustion behaviour of single die pellets was significantly different than those produced in a pilot scale pelletizing plant (semi-industrial scale pellet). That difference was due to variation in physical properties of pellets (e.g. density, and morphology).

  • 11.
    Bozaghian, Marjan
    et al.
    Swedish University of Agricultural Sciences, Department of Forest Biomaterials and Technology.
    Rebbling, Anders
    Umeå University, Department of Applied Physics and Electronics, Thermochemical Energy Conversion Laboratory.
    Larsson, Sylvia H.
    Swedish University of Agricultural Sciences, Department of Forest Biomaterials and Technology, Biomass Technology Centre.
    Thyrel, Mikael
    Swedish University of Agricultural Sciences, Department of Forest Biomaterials and Technology.
    Xiong, Shaojun
    Swedish University of Agricultural Sciences, Department of Forest Biomaterials and Technology.
    Skoglund, Nils
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap. Umeå University, Department of Applied Physics and Electronics, Thermochemical Energy Conversion Laboratory.
    Combustion characteristics of straw stored with CaCO3 in bubbling fluidized bed using quartz and olivine as bed materials2018Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 212, s. 1400-1408Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The addition of Ca-containing compounds can reduce mass loss from agricultural biomass during storage. The resulting alkaline environment is detrimental to microorganisms present in the material. Theoretical analysis of Ca-containing biomass suggests that combustion properties are improved with respect to slagging. To validate the theoretical calculations, barley straw was utilized as a typical model agricultural biomass and combustion characteristics of straw pre-treated with 2 and 4 w/w% CaCO3 for combined improvement of storage and combustion properties were determined through combustion at 700 °C in a bench-scale bubbling fluidized-bed reactor (5 kW) using quartz and olivine sand as bed materials. The combustion characteristics were determined in terms of elemental composition and compound identification in bed ash and bed material including agglomerates, fly ash, particulate matter as well as flue gas measurements. The addition of CaCO3 to straw had both positive and negative effects on its combustion characteristics. Both additive levels raised the total defluidization temperature for both quartz and olivine, and olivine proved to be less susceptible than quartz to reactions with alkali. With Ca-additives, the composition of deposits and fine particulate matter changed to include higher amounts of KCl potentially leading to higher risk for alkali chloride-induced corrosion. Flue gas composition was heavily influenced by CaCO3 additives by significantly elevated CO concentrations likely related to increased levels of gaseous alkali compounds. The results suggest that it is necessary to reduce gaseous alkali compounds, e.g. through kaolin or sulphur addition, if alkali-rich straw is to be co-combusted with Ca-rich biomass or large amounts of Ca-additives

  • 12.
    Carvalho, Lara
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Lundgren, Joakim
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Wetterlund, Elisabeth
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Wolf, Jens
    RISE Bioeconomy.
    Furusjö, Erik
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Methanol production via black liquor co-gasification with expanded raw material base: Techno-economic assessment2018Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 225, s. 570-584Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Entrained flow gasification of black liquor combined with downstream-gas-derived synthesis of biofuels in Kraft pulp mills has shown advantages regarding energy efficiency and economic performance when compared to combustion in a recovery boiler. To further increase the operation flexibility and the profitability of the biofuel plant while at the same time increase biofuel production, black liquor can be co-gasified with a secondary feedstock (blend-in feedstock). This work has evaluated the prospects of producing biofuels via co-gasification of black liquor and different blend-in feedstocks (crude glycerol, fermentation residues, pyrolysis liquids) at different blend ratios. Process modelling tools were used, in combination with techno-economic assessment methods. Two methanol grades, crude and grade AA methanol, were investigated. The results showed that the co-gasification concepts resulted in significant increases in methanol production volumes, as well as in improved conversion efficiencies, when compared with black liquor gasification; 5-11 and 4-10 percentage point in terms of cold gas efficiency and methanol conversion efficiency, respectively. The economic analysis showed that required methanol selling prices ranging from 55-101 €/MWh for crude methanol and 58-104 €/MWh for grade AA methanol were obtained for an IRR of 15%. Blend-in led to positive economies-of-scale effects and subsequently decreased required methanol selling prices, in particular for low cost blend-in feedstocks (prices below approximately 20 €/MWh). The co-gasification concepts showed economic competitiveness to other biofuel production routes. When compared with fossil fuels, the resulting crude methanol selling prices were above maritime gas oil prices. Nonetheless, for fossil derived methanol prices higher than 80 €/MWh, crude methanol from co-gasification could be an economically competitive option. Grade AA methanol could also compete with taxed gasoline. Crude glycerol turned out as the most attractive blend-in feedstock, from an economic perspective. When mixed with black liquor in a ratio of 50/50, grade AA methanol could even be cost competitive with untaxed gasoline.

  • 13.
    Carvalho, Lara
    et al.
    Bioenergy 2020+ GmbH.
    Vopienka, Elisabeth
    Bioenergy 2020+ GmbH.
    Pointner, Christian
    Bioenergy 2020+ GmbH.
    Lundgren, Joakim
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Verma, Vijay Kumar
    Bioenergy 2020+ GmbH.
    Haslinger, Walter
    Bioenergy 2020+ GmbH.
    Schmidl, Christoph
    Bioenergy 2020+ GmbH.
    Performance of a pellet boiler fired with agricultural fuels2013Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 104, s. 286-296Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The increasing demand for woody biomass increases the price of this limited resource, motivating the growing interest in using woody materials of lower quality as well as non-woody biomass fuels for heat production in Europe. The challenges in using non-woody biomass as fuels are related to the variability of the chemical composition and in certain fuel properties that may induce problems during combustion. The objective of this work has been to evaluate the technical and environmental performance of a 15 kW pellet boiler when operated with different pelletized biomass fuels, namely straw (Triticum aestivum), Miscanthus (Miscanthus × giganteus), maize (Zea mays), wheat bran, vineyard pruning (from Vitis vinifera), hay, Sorghum (Sorghum bicolor) and wood (from Picea abies) with 5% rye flour. The gaseous and dust emissions as well as the boiler efficiency were investigated and compared with the legal requirements defined in the FprEN 303-5 (final draft of the European standard 303-5). It was found that the boiler control should be improved to better adapt the combustion conditions to the different properties of the agricultural fuels. Additionally, there is a need for a frequent cleaning of the heat exchangers in boilers operated with agricultural fuels to avoid efficiency drops after short term operation. All the agricultural fuels satisfied the legal requirements defined in the FprEN 303-5, with the exception of dust emissions during combustion of straw and Sorghum. Miscanthus and vineyard pruning were the best fuels tested showing comparable emission values to wood combustion.

  • 14.
    Chalima, Angelina
    et al.
    National Technical University of Athens, Athens, Greece.
    Hatzidaki, Angeliki
    National Technical University of Athens, Athens, Greece.
    Karnaouri, Anthi
    National Technical University of Athens, Athens, Greece.
    Topakas, Evangelos
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik. National Technical University of Athens, Athens, Greece.
    Integration of a dark fermentation effluent in a microalgal-based biorefinery for the production of high-added value omega-3 fatty acids2019Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 241, s. 130-138Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Dark fermentation is an anaerobic digestion process of biowaste, used to produce hydrogen- for generation of energy- that however releases high amounts of polluting volatile fatty acids, such as acetic acid, in the environment. In order for this biohydrogen production process to become more competitive, the volatile fatty acids stream can be utilized through conversion to high added-value metabolites, such as omega-3 fatty acids. The docosahexaenoic acid is one of the two most known omega-3 fatty acids and has been found to be necessary for a healthy brain and proper cardiovascular function. The main source is currently fish, which obtain the fatty acid from the primary producers, microalgae, through the food chain. Crypthecodinium cohnii, a heterotrophic marine microalga, is known for accumulating high amounts of docosahexaenoic acid, while offering the advantage of assimilating various carbon sources, such as glucose, ethanol, glycerol and acetic acid. The purpose of this work was to examine the ability of a C. cohnii strain to grow on different volatile fatty acids, as well as, on a pretreated dark fermentation effluent and accumulate omega-3. The strain was found to grow well on relatively high concentrations of acetic, butyric or propionic acid as main carbon source in a fed-batch pH-auxostat. Most importantly, C. cohnii totally depleted the organic acid content of an ultra-filtrated dark fermentation effluent after 60 h of fed-batch cultivation, therefore offering a bioprocess not only able to mitigate environmental pollutants, but also to provide a solution for a sustainable energy production process. The accumulated docosahexaenoic acid content was as high as 29.8% (w/w) of total fatty acids. 

  • 15.
    Chen, Jingjing
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap. State Key Laboratory of Material-Oriented Chemical Engineering, Nanjing Tech University.
    Wu, Jiajun
    State Key Laboratory of Material-Oriented Chemical Engineering, Nanjing Tech University, Nanjing .
    Ji, Xiaoyan
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Lu, Xiaohua
    Key Laboratory of Material and Chemical Engineering, Nanjing Tech University, Nanjing .
    Wang, Changsong
    State Key Laboratory of Material-Oriented Chemical Engineering, Nanjing Tech University, Nanjing .
    Mechanism of waste-heat recovery from slurry by scraped-surface heat exchanger2017Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 207, s. 146-155Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Waste-heat recovery from discharged slurries can improve the net raw biogas production in the bio-methane process in order to meet the demand for a next-generation of anaerobic digestion. In this study, a numerical model of a scraped-surface heat exchanger was proposed with the consideration of the complete and precise rheological behaviour of the slurry of animal manure for the first time for achieving highly efficient waste-heat recovery. The rheological model results were verified with new experimental data measured in this work. Subsequently, the convective heat-transfer coefficient of the scraped-surface heat exchanger was calculated numerically with the proposed numerical model, and the performance was determined. Then, the contributions of waste-heat recovery from the slurry to the biogas production using a general shell-and-tube heat exchanger and the scraped-surface heat exchanger were calculated quantitatively and compared. For the case of scraped-surface heat exchanger, the increase of net raw biogas production can be up to 8.53%, which indicates that there is a great potential to increase the net raw biogas production in the bio-methane process using a scraped-surface heat exchanger with low-cost equipment and a compactible structure.

  • 16. Chen, Yifeng
    Yang, Zhuhong
    Lu, Xiaohua
    Ji, Xiaoyan
    CO2 Separation with a Hybrid Absorbent of Choline-2-pyrrolidinecarboxylic Acid/Polyethylene Glycol/WaterIngår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118Artikel i tidskrift (Refereegranskat)
  • 17.
    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.

  • 18.
    de Jong, Sierk
    et al.
    Copernicus Institute of Sustainable Development, Utrecht University.
    Hoefnagels, Ric
    Copernicus Institute of Sustainable Development, Utrecht University.
    Wetterlund, Elisabeth
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Pettersson, Karin
    RISE Research Institutes of Sweden.
    Faaij, André
    Energy Academy Europe, University of Groningen.
    Junginger, Martin
    Copernicus Institute of Sustainable Development, Utrecht University.
    Cost optimization of biofuel production: The impact of scale, integration, transport and supply chain configurations2017Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 195, s. 1055-1070Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This study uses a geographically-explicit cost optimization model to analyze the impact of and interrelation between four cost reduction strategies for biofuel production: economies of scale, intermodal transport, integration with existing industries, and distributed supply chain configurations (i.e. supply chains with an intermediate pre-treatment step to reduce biomass transport cost). The model assessed biofuel production levels ranging from 1 to 150 PJ a−1 in the context of the existing Swedish forest industry. Biofuel was produced from forestry biomass using hydrothermal liquefaction and hydroprocessing. Simultaneous implementation of all cost reduction strategies yielded minimum biofuel production costs of 18.1–18.2 € GJ−1 at biofuel production levels between 10 and 75 PJ a−1. Limiting the economies of scale was shown to cause the largest cost increase (+0–12%, increasing with biofuel production level), followed by disabling integration benefits (+1–10%, decreasing with biofuel production level) and allowing unimodal truck transport only (+0–6%, increasing with biofuel production level). Distributed supply chain configurations were introduced once biomass supply became increasingly dispersed, but did not provide a significant cost benefit (<1%). Disabling the benefits of integration favors large-scale centralized production, while intermodal transport networks positively affect the benefits of economies of scale. As biofuel production costs still exceeds the price of fossil transport fuels in Sweden after implementation of all cost reduction strategies, policy support and stimulation of further technological learning remains essential to achieve cost parity with fossil fuels for this feedstock/technology combination in this spatiotemporal context.

  • 19.
    Eleftheroglou, Nick
    et al.
    Faculty of Aerospace Engineering, TU Delft, the Netherlands.
    Mansouri, Sina Sharif
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Loutas, Theodoros
    Department of Mechanical Engineering & Aeronautics, University of Patras, Greece.
    Karvelis, Petros
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Georgoulas, George
    Department of Mechanical Engineering & Aeronautics, University of Patras, Greece.
    Nikolakopoulos, George
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Zarouchas, Dimitrios
    Faculty of Aerospace Engineering, TU Delft, the Netherlands.
    Intelligent data-driven prognostic methodologies for the real-time remaining useful life until the end-of-discharge estimation of the Lithium-Polymer batteries of unmanned aerial vehicles with uncertainty quantification2019Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 254, artikel-id 113677Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this paper, the discharge voltage is utilized as a critical indicator towards the probabilistic estimation of the Remaining Useful Life until the End-of-Discharge of the Lithium-Polymer batteries of unmanned aerial vehicles. Several discharge voltage histories obtained during actual flights constitute the in-house developed training dataset. Three data-driven prognostic methodologies are presented based on state-of-the-art as well as innovative mathematical models i.e. Gradient Boosted Trees, Bayesian Neural Networks and Non-Homogeneous Hidden Semi Markov Models. The training and testing process of all models is described in detail. Remaining Useful Life prognostics in unseen data are obtained from all three methodologies. Beyond the mean estimates, the uncertainty associated with the point predictions is quantified and upper/lower confidence bounds are also provided. The Remaining Useful Life prognostics during six random flights starting from fully charged batteries are presented, discussed and the pros and cons of each methodology are highlighted. Several special metrics are utilized to assess the performance of the prognostic algorithms and conclusions are drawn regarding their prognostic capabilities and potential.

  • 20.
    Eriksson, Gunnar
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Kjellström, Björn
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Assessment of combined heat and power (CHP) integrated with wood-based ethanol production2010Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 87, nr 12, s. 3632-3641Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

  • 21.
    Eriksson, Gunnar
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Kjellström, Björn
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Corrigendum to: Assessment of combined heat and power (CHP) integrated with wood-based ethanol production [Applied Energy 87 (12) (2010) 3632-3641]2011Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 88, nr 5, s. 1997-1998Artikel i tidskrift (Övrigt vetenskapligt)
  • 22.
    Grip, Niklas
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Matematiska vetenskaper.
    Grip, Carl-Erik
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Nilsson, Leif
    SSAB EMEA, Luleå.
    Wavelet study of dynamic variations in steel and ironmaking rest gases: Potential effect on external use2013Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 112, s. 1032-1040Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The surplus energy in rest gases is an important by-product in the SSAB EMEA steel plant in Luleå. The surplus is used in a local heat and power plant. Studies have been and are being carried out to find alternative use for the high calorific gases, especially the coke oven gas. The different gas flows typically are mixtures of irregularly distributed transients and non-periodic contents of different duration. Slowly varying fluctuations can probably be parried by good production planning. For shorter wavelengths some kind of safety margin could be appropriate, perhaps in the range 0.75–1.5 kN m3/h. However, the existing buffer capacity in gasholders, etc. is too small to cover the fluctuations. Good production planning can partly compensate low buffer capacity. An example from a period without gas holder is discussed.We describe analysis of the gas flows that can be used both for better production planning and for efficient external use, e.g., for fuel production. Rather than traditional Fourier analysis, we use wavelet analysis, which is better suited for analyzing the irregular and nonperiodic characteristics of the gas flows. We demonstrate such analysis on collected gas flow data from the SSAB EMEA steel plant and give some suggestions for how to make a good choice of wavelet basis for the analyzed signals.

  • 23.
    Gustafsson, Jonas
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Delsing, Jerker
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    van Deventer, Jan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Experimental evaluation of radiator control based on primary supply temperature for district heating substations2011Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 88, nr 12, s. 4945-4951Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this paper, we evaluate whether the primary supply temperature in district heating networks can be used to control radiator systems in buildings connected to district heating; with the purpose of increasing the ΔT. The primary supply temperature in district heating systems can mostly be described as a function of outdoor temperature; similarly, the radiator supply temperature in houses, offices and industries can also be described as a function of outdoor temperature. To calibrate the radiator control system to produce an ideally optimal radiator supply temperature that produces a maximized ΔT across the substation, the relationship between the primary supply temperature and outdoor temperature must be known. However, even if the relation is known there is always a deviation between the expected primary supply temperature and the actual temperature of the received distribution media. This deviation makes the radiator control system incapable of controlling the radiator supply temperature to a point that would generate a maximized ΔT. Published simulation results show that it is possible and advantageous to utilize the primary supply temperature for radiator system control. In this paper, the simulation results are experimentally verified through implementation of the control method in a real district heating substation. The primary supply temperature is measured by the heat-meter and is shared with the radiator control system; thus no additional temperature sensors were needed to perform the experiments. However additional meters were installed for surveillance purposes. To maintain a stable indoor temperature at times when the primary supply and outdoor temperatures deviates from their assumed relation, the radiator system flow must be controlled by an additional control-loop. The results confirms that it is possible to control the radiator system based on the primary supply temperature while maintaining comfort; however, conclusions regarding improvements in ΔT were hard to distinguish.

  • 24. Gustafsson, Jonas
    et al.
    Delsing, Jerker
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    van Deventer, Jan
    Improved district heating substation efficiency with a new control strategy2010Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 87, nr 6, s. 1996-2004Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this paper, we describe a new alternative control approach for indirectly connected district heating substations. Simulations results showed that the new approach results in an increased ΔT across the substation. Results were obtained for both ideal and non-ideal operation of the system, meaning that less water must be pumped through the district heating network, and a higher overall fuel efficiency can be obtained in the district heating power plants. When a higher fuel efficiency is achieved, the usage of primary fuel sources can be reduced. Improved efficiency also increases the effective heat transfer capacity of a district heating network, allowing more customers to be connected to an existing network without increasing the heating plant or network capacity.Also, if combined heat and power plants are used to produce the heat, the increased ΔT will result in a further improved overall fuel efficiency, as more electricity can be produced with colder cooling water.The idea behind the new control method is to consider the temperature of the water supplying the district heating substation with heat, often referred to as the primary supply temperature. This represents a logical next step, as currently, the only parameter generally taken into account or measured when controlling the temperature level of the radiator circuit is the local outdoor temperature. In this paper we show how the primary supply temperature together with thermodynamic knowledge of the building can be used to maximize the ΔT across the district heating substation.

  • 25.
    Imai, Akihisa
    et al.
    School of Environment and Society, Tokyo Institute of Technology, Yokohama, Japan.
    Hardi, Hardi
    Department of Environmental Science and Technology, Tokyo Institute of Technology, Yokohama, Japan.
    Lundqvist, Petter
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Furusjö, Erik
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap. Unit of Climate and Sustainable Cities, IVL Swedish Environmental Research Institute, Stockholm, Sweden.
    Kirtania, Kawnish
    Department of Chemical Engineering, Bangladesh University of Engineering and Technology, Dhaka, Bangladesh.
    Karagöz, Selhan
    Department of Chemistry, Karabük University, Karabük, Turkey.
    Tekin, Kubilay
    Department of Environmental Engineering, Karabük University, Karabük, Turkey.
    Yoshikawa, Kunio
    School of Environment and Society, Tokyo Institute of Technology, Yokohama, Japan.
    Alkali-catalyzed hydrothermal treatment of sawdust for production of a potential feedstock for catalytic gasification2018Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 231, s. 594-599Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This study investigates the effects of reaction temperature and catalyst loading on product yields and fuel properties of produced slurry during the alkali catalyzed hydrothermal treatment (HTT) of pine sawdust. The yield of the liquid fraction, or the aqueous product (AP), at process temperatures of 180–260 °C obtained after solid/liquid separation of the slurry ranged from 11.1 to 34.3 wt% on a dry, ash free basis. The fuel quality of the produced slurry, such as the elemental composition and the higher heating value (HHV), was mainly affected by the catalyst loading. An increase in the catalyst loading caused the ash content to increase. Although the increase in temperature leads to a higher liquid fraction in the slurry making it more homogeneous, its contribution to the elemental composition of the whole slurry was limited. HHV of the produced slurry ranged from 12.0 to 16.4 MJ/kg. These values are comparable to that of black liquor (BL), which has previously been shown to be a promising feedstock for gasification in a pilot scale entrained flow gasifier. These results imply the possibility of a fuel switch from BL to the HTT slurry for entrained flow gasification though its gasification reactivity and conversion characteristics must be investigated further.

  • 26.
    Ji, Xiaoyan
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Lundgren, Joakim
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Wang, Chuan
    Dahl, Jan
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Grip, Carl-Erik
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Simulation and energy optimization of a pulp and paper mill: evaporation plant and digester2012Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 97, nr Spec. Issue, s. 30-37Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A detailed mathematical process integration model of a pulp and paper mill in the Northern Sweden has been developed. The main objective of this work has been set to describe the practical development of the model with particular emphasis on the development of the digester and evaporation plant sub-models. Actual plant measurements have been used to validate the model. By implementing the sub-models into the complete plant model, the influence of different operation parameters on the overall plant performance has been investigated. Furthermore, introductory studies with the main objective to minimize the plant energy cost have been carried out.

  • 27. Johansson, Lars
    et al.
    Westerlund, Lars
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Energy efficient bio fuel drying with an open absorption system: parameter study in order to reduce investment costs2000Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 67, nr 3, s. 231-244Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A pilot plant using the open absorption system for drying of timber and bio fuel has been realized at a sawmill located in the northern part of Sweden. The technique decreases the energy demand for the dryers considerably and the system has an availability of about 8000 h per year. Compared with other drying techniques, the investment cost is high due to large airflow and therefore large apparatus. The main part of the investment cost, i.e. about 70% originates from the bio fuel dryer and the absorbers. In order to decrease the initial cost a parameter study has been made to investigate the possibilities to reduce the airflow of the drying process, i.e. bio fuel dryer and absorber. Parameters studied are drying temperature, salt concentration and cooling of the airflow during the absorption process. Measured values from the pilot plant have been used as a reference case. The results show that it is possible to decreases the airflow by 31% when using a higher drying temperature. Higher salt concentration decreases the airflow by approximately 32% and cooling during absorption makes it possible to decrease the airflow by 50%. In order to minimize the airflow, the three parameters were combined. In this case it is possible to decrease the airflow by approximately 60%. The electrical input for the plant is also high due to large air and solution flows. By decreasing the airflow, the required electrical input will also decrease since the fan power is proportional to the volume airflow. The results clearly show that it is possible to reduce the airflow and therefore the investment costs compared with the pilot plant.

  • 28. Johansson, Lars
    et al.
    Westerlund, Lars
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Energy savings in indoor swimming-pools: comparison between different heat-recovery systems2001Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 70, nr 4, s. 281-303Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In indoor swimming-pool facilities, the energy demand is large due to ventilation losses with the exhaust air. Since water is evaporated from the pool surface, the exhaust air has a high water content and specific enthalpy. Because of the low temperature, the heat from the evaporation is difficult to recover. In this paper, the energy demand for the conventional ventilation technique in indoor swimming pools is compared to two different heat-recovery techniques, the mechanical heat pump and the open absorption system. The mechanical heat-pump is the most widely used technique in Sweden today. The open absorption system is a new technique in this application. Calculations have been carried out on an hourly basis for the different techniques. Measurements from an absorption system pilot-plant installed in an indoor swimming pool in the northern part of Sweden have been used in the calculations. The results show that with the mechanical heat pump, the electrical input increases by 63 MWh/year and with the open absorption system 57 MWh/year. However, a mechanical heat-pump and an open absorption system decrease, the annual energy demand from 611 to 528 and 484 MWh respectively, which correspond to decreases of approximately 14 and 20% respectively. The electricity input will increase when using heat-recovery techniques. Changing the climate in the facility has also been investigated. An increased temperature decreases the energy demand when using the conventional ventilation technique. However, when either the mechanical heat-pump or the open absorption system is used, the energy demand is increased when the temperature is increased. Therefore increasing the temperature in the facility when using the conventional technique should be considered the first measure to reduce the energy demand.

  • 29.
    Johansson, Tim
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Olofsson, Thomas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Mangold, Mikael
    Research Institutes of Sweden, City Development.
    Development of an energy atlas for renovation of the multifamily building stock in Sweden2017Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 203, s. 723-736Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Many studies have highlighted the importance of retrofitting to mitigate the energy use of building stocks. An important step in the development of renovation strategy and energy conservation advising is to gather information of the energy performance of the existing buildings. However, renovation strategies must also consider the socio-economic challenges associated with the cost of energy retrofitting. This paper describes the development of an energy atlas of the multifamily building stock in Sweden for visualizing and analyzing energy use and renovation needs. The atlas has been developed using Extract Transform and Load technology (ETL) to aggregate information on the energy performance, building ownership, renovation status, and socio-economic status of inhabitants from various data sources. The atlas can visualize the energy use and renovation status of multifamily buildings in 2D maps and 3D models, displaying data for either individual buildings or aggregated data on spatial scales ranging from 250 × 250 m squares through district and municipality to county areas. A demonstration of its use on national and city scales indicates that energy retrofits of multifamily buildings reaching a service life of 50 years can reduce the energy use of the existing building stock by up to 50% relative to 1990. However, costs associated with renovation and energy retrofits of multifamily buildings can be problematic, especially in economically weak suburbs. A good understanding of past and future renovation needs and socio-economic consequences is important in the development of a sustainable national renovation strategy.

  • 30. Jonsson, Pontus
    et al.
    Mulu, Berhanu
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Strömningslära och experimentell mekanik.
    Cervantes, Michel
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Strömningslära och experimentell mekanik.
    Experimental investigation of a Kaplan draft tube: Part II: Off-design conditions2012Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 94, nr 2, s. 71-83Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Off-design conditions of hydropower turbines are becoming more frequent with the deregulation of electricity markets and the introduction of renewable energy resources. Originally, turbines were not built to operate under such conditions. It is evident that there is a need to develop turbines that can operate under off-design conditions while attaining high efficiency. This may be achieved with computational fluid dynamics (CFD). However, the complexity of Kaplan turbine flows is challenging to treat using CFD. Therefore, detailed experimental investigations are necessary to validate and develop CFD. This paper presents an investigation of a modern design Kaplan turbine model. The measurements were performed in the draft tube with laser Doppler anemometry and flush-mounted pressure sensors, with a focus on the part load and high load operation of the turbine. Mean and phase-averaged quantities are presented for the velocity and pressure along several sections. A contra-rotating flow region was observed under high load operation. Under part load operation, a rotating vortex rope (RVR) develops due to vortex breakdown. The presence of the RVR significantly reduces the draft tube performance.

  • 31.
    Kharseh, Mohamad
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Arkitektur och vatten.
    Altorkmany, Lobna
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Arkitektur och vatten.
    How global warming and building envelope will change buildings energy use in central Europe2012Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 97, nr Spec. Issue, s. 999-1004Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The thermal performance of ground source heat pump systems (GSHP) strongly depends on ground temperature and energy demand for heating and cooling during the year. Certainly, increasing the global temperature means warmer ground. On the other hand, the thermal load of a building is influenced by thermal quality of building envelop (TQBE) and also influenced by the ambient air temperature. There is absolutely no doubt that the global temperature has increased during the last century. Over time, the buildings designs are changing. These result in changed thermal load of the buildings, ground temperature, and thereby changed the thermal performance of GSHPs. The objective of current work was to investigate the impact of TQBE under different global warming scenarios on driving energy and construction cost of GSHPs in Vienna. This was achieved by comparing the driving energy of the GSHP as well the required total length of the borehole heat exchanger for different GW scenarios and different TQBE. Under climate conditions of Vienna city study shows that improving the TQBE and increasing ambient air temperature result in reduced driving energy of GSHP. While is it not obvious for the required total borehole depth. Namely, after a certain degree of GW, increasing TQBE might result in increased required borehole depth.

  • 32. Leduc, Sylvain
    et al.
    Lundgren, Joakim
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Franklin, O.
    International Institute for Applied System Analysis (IIASA), Laxenburg.
    Dotzauer, E.
    Mälardalen University.
    Location of a biomass based methanol production plant: a dynamic problem in northern Sweden2010Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 87, nr 1, s. 68-75Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Concerning production and use of biofuels, mismatch between the locations of feedstock and the biofuel consumer may lead to high transportation costs and negative environmental impact. In order to minimize these consequences, it is important to locate the production plant at an appropriate location. In this paper, a case study of the county of Norrbotten in northern Sweden is presented with the purpose to illustrate how an optimization model could be used to assess a proper location for a biomass based methanol production plant. The production of lignocellulosic based methanol via gasification has been chosen, as methanol seems to be one promising alternative to replace fossil gasoline as an automotive fuel and Norrbotten has abundant resources of woody biomass. If methanol would be produced in a stand-alone production plant in the county, the cost for transportation of the feedstock as well as the produced methanol would have great impact on the final cost depending on where the methanol plant is located. Three different production plant sizes have been considered in the study, 100, 200 and 400 MW (biomass fuel input), respectively. When assessing a proper location for this kind of plant, it is important to also consider the future motor fuel demand as well as to identify a heat sink for the residual heat. In this study, four different automotive fuel- and district heating demand scenarios have been created until the year 2025. The results show that methanol can be produced at a maximum cost of 0.48 €/l without heat sales. By selling the residual heat as district heating, the methanol production cost per liter fuel may decrease by up to 10% when the plant is located close to an area with high annual heat demand.

  • 33.
    Leduc, Sylvain
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap. International Institute for Applied System Analysis (IIASA), A-2361 Laxenburg, Austria.
    Natarajan, Karthikeyan
    International Institute for Applied System Analysis (IIASA), A-2361 Laxenburg, Austria.
    Dotzauer, Erik
    Mälardalen University, Sweden.
    McCallum, Ian
    International Institute for Applied System Analysis (IIASA), A-2361 Laxenburg, Austria.
    Obersteiner, Michael
    International Institute for Applied System Analysis (IIASA), A-2361 Laxenburg, Austria.
    Optimizing biodiesel production in India2009Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 86, nr Suppl. 1, s. S125-S131Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    India is expected to at least double its fuel consumption in the transportation sector by 2030. To contribute to the fuel supply, renewable energies such as jatropha appear to be an attractive resource for biodiesel production in India as it can be grown on waste land and does not need intensive water supply. In order to produce biodiesel at a competitive cost, the biodiesel supply chain - from biomass harvesting to biodiesel delivery to the consumers - is analyzed. A mixed integer linear programming model is used in order to determine the optimal number and geographic locations of biodiesel plants. The optimization is based on minimization of the costs of the supply chain with respect to the biomass, production and transportation costs. Three biodiesel blends are considered, B2, B5 and B10. For each blend, 13 scenarios are considered where yield, biomass cost, cake price, glycerol price, transport cost and investment costs are studied. A sensitivity analysis is carried out on both those parameters and the resulting locations of the plants. The emissions of the supply chain are also considered. The results state that the biomass cost has most influence on the biodiesel cost (an increase of feedstock cost increases the biodiesel cost by about 40%) and to a lower effect, the investment cost and the glycerol price. Moreover, choosing the right set of production plant locations highly depends on the scenarios that have the highest probability to occur, for which the production plant locations still produce a competitive biodiesel cost and emissions from the transportation are minimum. In this study, one set of plant locations happened to meet these two requirements.

  • 34.
    Lindman, Åsa
    et al.
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Samhällsvetenskap.
    Söderholm, Patrik
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Samhällsvetenskap.
    Wind energy and green economy in Europe: Measuring policy-induced innovation using patent data2016Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 179, s. 1351-1359Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The green economy policy discourse has devoted a lot of attention to the design of public policy addressing low-carbon technologies. In this paper we examine the impacts of public R&D support and feed-in tariff schemes on innovation in the wind energy sector. The analysis is conducted using patent application data for four western European countries over the period 1977–2009. Different model specifications are tested, and the analysis highlights important policy interaction effects. The results indicate that both public R&D support and feed-in tariffs have positively affected patent application counts in the wind power sector. The (marginal) impact on patent applications of increases in feed-tariffs has also become more profound as the wind power technology has matured. There is also some evidence of policy interaction effects in that the impact of public R&D support to wind power is greater at the margin if it is accompanied by the use of feed-in tariff schemes. These results support the notion that technological innovation requires both R&D and learning-by-doing, and for this reason public R&D programs should typically not be designed in isolation from practical applications. The paper ends by outlining some important avenues for future research.

  • 35.
    Lundgren, Joakim
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Ekbom, T.
    Grontmij AB, Energy and Power, Stockholm.
    Hulteberg, Christian
    Nordlight AB, Limhamn.
    Larsson, Mikael
    Grip, Carl-Erik
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Nilsson, L.eif K.
    SSAB EMEA, Luleå.
    Tunå, Per
    Lund University, Chemical Engineering.
    Methanol production from steel-work off-gases and biomass based synthesis gas2013Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 112, s. 431-439Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Off-gases generated during steelmaking are to a large extent used as fuels in process units within the plant. The surplus gases are commonly supplied to a plant for combined heat and power production. The main objective of this study has been to techno-economically investigate the feasibility of an innovative way of producing methanol from these off-gases, thereby upgrading the economic value of the gases. Cases analyzed have included both off-gases only and mixes with synthesis gas, based on 300 MWth of biomass. The SSAB steel plant in the town of Luleå, Sweden has been used as a basis. The studied biomass gasification technology is based on a fluidized-bed gasification technology, where the production capacity is determined from case to case coupled to the heat production required to satisfy the local district heating demand. Critical factors are the integration of the gases with availability to the synthesis unit, to balance the steam system of the biorefinery and to meet the district heat demand of Luleå. The annual production potential of methanol, the overall energy efficiency, the methanol production cost and the environmental effect have been assessed for each case. Depending on case, in the range of 102,000–287,000 ton of methanol can be produced per year at production costs in the range of 0.80–1.1 EUR per liter petrol equivalent at assumed conditions. The overall energy efficiency of the plant increases in all the cases, up to nearly 14%-units on an annual average, due to a more effective utilization of the off-gases. The main conclusion is that integrating methanol production in a steel plant can be made economically feasible and may result in environmental benefits as well as energy efficiency improvements.

  • 36.
    Ma, Chunyan
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap. State Key Laboratory of Material-Oriented Chemical Engineering, Nanjing Tech University, Nanjing.
    Liu, Chang
    State Key Laboratory of Material-Oriented Chemical Engineering, Nanjing Tech University, Nanjing.
    Lu, Xiaohua
    State Key Laboratory of Material-Oriented Chemical Engineering, Nanjing Tech University, Nanjing.
    Ji, Xiaoyan
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Erratum: Techno-economic analysis and performance comparison of aqueous deep eutectic solvent and other physical absorbents for biogas upgrading2019Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 235, s. 1669-1670Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The authors regret to inform that there are errors in the vertical axis of Figs. 4 and 5 as well as corresponding text. The corrected versions are given below. (Figure presented.) Fig. 4b: the left y-axis should read “$·Nm-3 CH4” instead of “k$·Nm-3 CH4”; The corrected version of Fig. 5 is shown below. Abstract: The text at the end of Abstract: ‘For the case with …respectively’ should read: “…with AQ50wt.%DESand PC decrease by…” instead of “…with PC and AQ50wt.%DES decrease by…” Section 3.3.2: The text at the end of paragraph 5: ‘The results of specific TAC of using…than that using water, respectively. ’ should read: “…using AQ50wt.%DES and PC decrease by ….” instead of “…using PC and AQDES decrease by…” “…using AQ50wt.%DES and PC increase up to…” instead of “…using PC and AQ50wt.%DESincrease up to…” The text at the end of paragraph 6: ‘While, using…raw biogas capacity. ’ should read: “…and 25% than water…” instead of “…and 50% than water…” Conclusion: The text at the end of paragraph 2: ‘The results of specific TAC of using PC …than PC should be developed.’ should read: “…using AQ50wt.%DES and PC decrease by…” instead of “…using PC and AQ50wt.%DES decrease by…” “…using AQ50wt.%DES and PC treated with…” instead of “…using PC and AQ50wt.%DES treated with…” The above errors do not reflect any calculations errors and do not compromise the findings of the paper. The authors would like to apologize for any inconvenience caused. 

  • 37.
    Ma, Chunyan
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap. State Key Laboratory of Material-Oriented Chemical Engineering, Nanjing Tech University, Nanjing.
    Liu, Chang
    State Key Laboratory of Material-Oriented Chemical Engineering, Nanjing Tech University, Nanjing.
    Lu, Xiaohua
    State Key Laboratory of Material-Oriented Chemical Engineering, Nanjing Tech University, Nanjing.
    Ji, Xiaoyan
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Techno-economic analysis and performance comparison of aqueous deep eutectic solvent and other physical absorbents for biogas upgrading2018Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 225, s. 437-447Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Biogas has been considered as an alternative renewable energy, and CO2 removal from raw biogas (i.e. biogas upgrading) is needed for producing biomethane to be used as vehicle fuels or injected into the natural gas grid. Biogas upgrading with physical absorbents, such as water and other commercial organic solvents, is simple, efficient and with low energy requirements for regeneration. Recently, deep eutectic solvents (DESs) with nonvolatility, nonflammability and low price have been reported as promising alternatives to replace conventional physical absorbents in many research areas including biogas upgrading. However, the performances of these physical solvents including conventional physical absorbents and DES-based solvents have not been evaluated and compared with each other. In this work, the properties of 4 physical solvents (i.e. water, dimethyl ether of polyethylene glycol (DEPG), propylene carbonate (PC), and aqueous DES (AQDES)) were compared. Furthermore, a conceptual process was developed to upgrade biogas with these solvents and simulated based on Aspen Plus in order to conduct performance comparison. The simulation results of energy utilization, the amount of recirculated solvents and the diameters of absorber and desorber were analyzed and compared based on equilibrium and rate-based approaches, respectively. The simulation results based on the rate-based approach were further used to estimate the costs of biogas upgrading process with a same raw biogas capacity for comparison. Meanwhile, the specific cost of biogas upgrading process with a same size of equipment was also evaluated. The results show that the CO2 solubility, selectivity and viscosity are three more important properties, providing valuable information for developing novel physical solvents for CO2 separation. The simulation results show that the equilibrium and rate-based approaches result in different conclusions, especially when the solvent viscosity is relatively high, and the rate-based approach is preferable. Based on the simulation results from the rate-based approach, the performances of AQDES and PC are similar with a same amount of energy utilization, that is around 11% lower than water, and DEPG is inferior to water. For the case with the same gas capacity, the total annual costs of biogas upgrading process with these solvents show the following order: DEPG > AQ60wt.%DES > water > AQ50wt.%DES ≈ PC. For the case with the same size of equipment, compared to water, the total specific costs of biogas upgrading process with PC and AQ50wt.%DES decrease by about 30% and 45%, respectively, and the treated biogas capacities increase to 1.5 and 2 times, respectively. In general, both PC and AQ50wt.%DES show better performance than the other solvents. Considering that DES is an environmentally benign solvent, and the performance of DES can be greatly improved by further designing, it is more promising

  • 38.
    Ma, Chunyan
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap. College of Chemical Engineering, Nanjing Tech University, Nanjing.
    Xie, Yujiao
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Ji, Xiaoyan
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Liu, Chang
    College of Chemical Engineering, Nanjing Tech University, Nanjing .
    Lu, Xiaohua
    College of Chemical Engineering, Nanjing Tech University, Nanjing .
    Modeling, simulation and evaluation of biogas upgrading using aqueous choline chloride/urea2017Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 229, nr 1, s. 1269-1283Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Biogas has been considered as an alternative renewable energy, and raw biogas needs to be upgraded in order to be used as vehicle fuels or injected into the natural gas grid. In this work, the conceptual process for biogas upgrading using aqueous choline chloride (ChCl)/urea (1:2 on a molar basis) was developed, simulated and evaluated based on the commercialized software Aspen Plus. Reliable thermophysical properties and phase equilibria are prerequisite for carrying out process simulation. In order to carry out the process simulation, the thermophysical properties of ChCl/Urea (1:2) and its aqueous solutions as well as the phase equilibria of gas-ChCl/Urea (1:2), ChCl/Urea (1:2)-H2O and gas-ChCl/Urea (1:2)-H2O were surveyed and evaluated. After evaluation, the consistent experimental data of these thermophysical properties were fitted to the models embedded in Aspen Plus. The properties needed but without available experimental results were predicted theoretically. The Non-Random Two-Liquid model and the Redlich-Kwong equation (NRTL-RK) model were used to describe the phase equilibria. The equilibrium approach was used for process simulation. Sensitivity analysis was conducted to determine the reasonable operating parameters. With a set of reasonable operating conditions, the effects of ChCl/Urea (1:2) content on the total energy utilization, the diameters and pressure drops of absorber and desorber as well as the environmental assessment of the process were studied. The simulation results showed that, with the addition of ChCl/Urea (1:2), the total energy utilization decreased by 16% compared to the process with pure water, and the diameters of both absorber and desorber decreased with increasing content of ChCl/Urea (1:2). The process using aqueous ChCl/Urea (1:2) was more environmentally benign than that with pure water. Therefore, aqueous ChCl/Urea (1:2) is a promising solvent for biogas upgrading.

  • 39.
    Masi, Massimo
    et al.
    Department of Mechanical Engineering, University of Padova.
    Toffolo, Andrea
    Antonello, Marco
    Department of Mechanical Engineering, University of Padova.
    Experimental analysis of a motorbike high speed racing engine2010Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 87, nr 5, s. 1641-1650Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Power gain is the main objective in any motorbike competition. Despite of the wide literature on theoretical and experimental methods for increasing engine power, there is a general lack of data about tests on racing engine performance due to the obvious manufacturers' reluctance to spread information, especially for recent high technological level applications. This paper, instead, presents all the main results of the experimental tests conducted on a motorbike engine both in the original stock arrangement and in a modified configuration proposed in compliance with the Technical Regulations of the 2007 FIM Road Racing Supersport Italian Championship (CIV). Traditional testing techniques (steady-flow discharge coefficients measurements and chassis dynamometer tests performed in the slow speed ramp mode) are chosen to reduce time and costs and to limit engine wearing while obtaining an acceptable degree of accuracy. It is also proved that the tests to assess the improvements obtained with design changes could not have been completed in the steady-state mode using a single engine because of the short life cycle of racing engines due to wearing, which would have altered the comparisons. Test results show a 16% and 33% rise in torque and power for the racing configuration, reaching the state of the art of the best performing engines in the Italian Supersport racing class

  • 40.
    Matelli, José Alexandre
    et al.
    NASA Ames Research Center, Intelligent Systems Division, Discovery and Systems Health, Moffett Field, CA.
    Goebel, Kai
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik. NASA Ames Research Center, Intelligent Systems Division, Discovery and Systems Health.
    Conceptual design of cogeneration plants under a resilient design perspective: Resilience metrics and case study2018Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 215, s. 736-750Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The conceptual design phase is the first step in the design process of an engineering system. Most engineering systems, including cogeneration plants, may and likely will experience some malfunctions during its life cycle. The metrics typically considered in the conceptual design phase (and for analysis and optimization) of energy systems are cost, efficiency and environmental impacts. Quite rarely are operational considerations about malfunctions integrated during the conceptual design phase. Resilient design, or design for resilience, addresses this gap as illustrated here in the area of energy conversion and conservation of energy processes by examining the conceptual design of a cogeneration plant. Resilient design is a relatively new research field where the engineering system is designed such that it can optimally recover from failures. The main challenge is to quantify the resilience in early design phases, since there is not much detailed information about system components available at this point. To address these challenges, this paper introduces a novel resilient design framework that uses new metrics within a Monte Carlo-based assessment approach. The framework is exercised on conceptual designs of cogeneration plants. Results from this framework are compared against those from a methodology based on complex networks theory that has been previously suggested in the literature. The former presented more consistent results than the latter and we discuss the differences. Results also show that the concept with higher efficiency was not the one with higher resilience. Finally, we discuss how to integrate specific failure probabilities information into the framework (should that information be available), and deliberate on relations between resilience, fault handling strategies and design requirements.

  • 41.
    Mesfun, Sennai
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Toffolo, Andrea
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Optimization of process integration in a Kraft pulp and paper mill: Evaporation train and CHP system2013Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 107, s. 98-110Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A great interest has been arising about the production of fuels and advanced chemicals from renewable resources such as wooden biomass in the so-called biorefineries. Pulp and paper mills are often seen as the most obvious fundamental module of such industrial sites, because of the common feedstock and the chemical transformations that already occur in the process. In this paper the model of real Kraft pulp and paper mill is developed and optimized from energetic point of view using process integration techniques, in order to assess the potential for energy saving and to establish a starting point for future research on biorefinery sites. Improvements to the configurations of the multi-effect evaporator and of the steam cycle in the CHP system have been introduced, and three different levels of heat integration boundaries have been considered (multi-effect evaporator, mill sub-processes, and total site). Results indicate a significant potential for the decrease in thermal energy requirement and/or the increase in power production for the same pulp and paper production.

  • 42.
    Mulu, Berhanu
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Strömningslära och experimentell mekanik.
    Jonsson, Pontus
    Cervantes, Michel
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Strömningslära och experimentell mekanik.
    Experimental investigation of a Kaplan draft tube: Part I: best efficiency point2012Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 93, s. 695-706Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Hydropower, originally designed as a base electrical power, is now used to balance grid fluctuations that are primarily produced by market deregulation and the introduction of other renewable energy resources. New turbine designs must account for such constraints while also achieving high efficiency. Computational fluid dynamics, now an integrated tool in the hydraulic industry, requires accurate and detailed experimental data for validation purposes.The present work presents the investigation of a modern Kaplan turbine model combined with laser Doppler anemometry and flush-mounted pressure sensors, with a focus on the draft tube at the best turbine efficiency. Mean and phase-resolved quantities are presented for the velocity and pressure at several locations. The results demonstrate the strong influence of the swirl leaving the runner for a well-functioning draft tube as well as the negative impact of the draft tube cone. The blade-hub clearance is also found to have an impact on the flow beneath the runner cone.

  • 43.
    Pettersson, Karin
    et al.
    Chalmers University of Technology, Department of Energy and Environment, Division of Heat and Power Technology , Chalmers University of Technology.
    Wetterlund, Elisabeth
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Athanassiadis, Dimitris
    SLU Swedish University of Agricultural Sciences.
    Lundmark, Robert
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Samhällsvetenskap.
    Ehn, Christian
    Innventia AB, SE-114 86 Stockholm, Sweden.
    Lundgren, Joakim
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Berglin, Niklas
    Innventia AB, SE-114 86 Stockholm, Sweden.
    Integration of next-generation biofuel production in the Swedish forest industry – A geographically explicit approach2015Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 154, s. 317-332Artikel i tidskrift (Refereegranskat)
  • 44.
    Prabowo, Bayu
    et al.
    Department of Environmental Science and Technology, Tokyo Institute of Technology, Yokohama.
    Aziz, Muhammad
    Solutions Research Laboratory, Tokyo Institute of Technology.
    Umeki, Kentaro
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Susanto, Herri
    Department of Chemical Engineering, Institut Teknologi Bandung.
    Yan, Mi
    State Key Laboratory of Clean Energy Utilization, Zhejiang University.
    Yoshikawa, Kunio
    Department of Environmental Science and Technology, Tokyo Institute of Technology, Yokohama, Tokyo Institute of Technology.
    CO2-recycling biomass gasification system for highly efficient and carbon-negative power generation2015Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 158, s. 97-106, artikel-id 6848Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This study explored the feasibility of biomass CO2 gasification as an effective method for implementing the concept of a carbon-negative power system through bioenergy with carbon capturing and storage. A CO2-recycling biomass gasification system was developed and examined using the thermal equilibrium model. Sensitivity analysis was performed by varying the gasifier temperature from 750 to 950 °C, and the turbine inlet temperature (TIT) and turbine exit temperature (TET) of the gas turbine from 1000 to 1200 °C and from 900 to 1000 °C, respectively. The gasifier efficiency was increased by an increase in the CO2 recycling ratio with the more significant trend shown at the lower gasifier temperature. The turbine efficiency decreased as the CO2 recycling ratio to the gasifier increased over a certain limit, a ratio of 0.55 in most cases. A pressure ratio of 2.3 was optimum in terms of turbine efficiency. Under the examined conditions, the optimum conditions for gaining the highest system efficiency, 39.03%, were a recycling ratio of 0.55 and a TET and TIT of 1000 and 1200 °C respectively. The proposed system had 7.57% higher efficiency and exhausted 299.15 g CO2/kW h less CO2 emissions than conventional air gasification. Combined with carbon capturing and storage, the system potentially generates carbon-negative power generation with intensity of around 1.55-kg CO2/kg wet-biomass and a maximum efficiency penalty of 6.89%.

  • 45.
    Prabowo, Bayu
    et al.
    Department of Environmental Science and Technology, Tokyo Institute of Technology, Yokohama.
    Umeki, Kentaro
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Yan, Mi
    State Key Laboratory of Clean Energy Utilization, Zhejiang University.
    Nakamura, Masato R.
    Department of Mechanical Engineering and Industrial Design Technology, New York City College of Technology (City Tech), City University of New York (CUNY).
    Castradi, Marco J.
    Department of Chemical Engineering, The City College of New York, City University of New York (CUNY).
    Yoshikawa, Kunio
    Department of Environmental Science and Technology, Tokyo Institute of Technology, Yokohama.
    CO2–steam mixture for direct and indirect gasification of rice straw in a downdraft gasifier: Laboratory-scale experiments and performance prediction2014Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 113, s. 670-679Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper explored the feasibility of CO2 as alternative gasifying agent of steam to obtain higher thermal efficiency in biomass gasification. The effect of the gasifying agent on gas evolution and thermal efficiency was examined by using a lab scale downdraft gasifier. The results were also compared with the output of pyrolysis with N2. The reaction atmosphere in indirect and direct gasification was simulated by carrying out the experiments without and with O2 presence. The reaction conditions were varied in the temperature range from 750 °C to 950 °C by changing the CO2 molar fraction in gasifying agent to the ratio of 0, 30 and 60 vol.% in balance with steam. 40 vol.% of N2 fraction was kept during O2 free experiments, while 31.7 vol.% of N2 and 8.3 vol.% O2 were kept during the experiments with the presence of O2. At all examined condition, gasification yielded more combustible gas than pyrolysis. Furthermore, high CO2 fraction in gasifying agent generally resulted in low H2 yield and high CO yield. These substitutions mostly lowered the energy yield of the producer gas, but in the other hand also reduced the preheating energy of gasifying agent. Thus, optimizations of these changes were investigated for gaining highest thermal efficiency of the gasification process. Highest thermal efficiency of the process without O2 was 52% under N2 (40 vol.%)–CO2 (60 vol.%) atmosphere at the temperature of 850 °C. For the process with O2, where the part of gasifying agent preheating energy supplied by the biomass partial combustion, the highest thermal efficiency was 60% under the CO2 (60 vol.%)–O2 (8.3 vol.%)–N2 (31.7 vol.%) atmosphere at the temperature of 950 °C. CO2 utilization as a gasifying agent potentially increases the thermal efficiency of biomass conversion process compared with pyrolysis or conventional indirect and direct gasification, i.e. pure-steam gasification and O2–steam gasification.

  • 46.
    Sandberg, Johan
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Larsson, Mikael
    Wang, Chuan
    Dahl, Jan
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Lundgren, Joakim
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    A new optimal solution space based method for increased resolution in energy system optimisation2012Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 92, nr 1, s. 583-592Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this paper a new method for increased time resolution in multi-period Mixed Integer Linear Programming (MILP) optimisation is presented and applied to a district heating system. The proposed method facilitates the analysis of many time periods in multi period MILP optimisation projects. In the paper, a 365 time period model spanning 1 year developed with the novel method is compared to a 12 time period model developed with a more conventional methodology. The new method offers a significant decrease in the amount of input data for multi period models and facilitates changes to the analysed time span or resolution in time. In the application of the new method oil savings of 7% compared to the current operational strategy of the district heating system are revealed.

  • 47.
    Suopajärvi, Hannu
    et al.
    Process Metallurgy Research Unit, University of Oulu.
    Umeki, Kentaro
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Mousa, Elsayed
    Swerea MEFOS, Process Integration Department.
    Hedayati, Ali
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Romar, Henrik
    Research Unit of Sustainable Chemistry, University of Oulu.
    Kemppainen, Antti
    Process Metallurgy Research Unit, University of Oulu.
    Wang, Chuan
    Swerea MEFOS, Process Integration Department.
    Phounglamcheik, Aekjuthon
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Tuomikoski, Sari
    Research Unit of Sustainable Chemistry, University of Oulu.
    Norberg, Nicklas
    Future Eco North Sweden AB.
    Andefors, Alf
    Future Eco North Sweden AB.
    Öhman, Marcus
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Lassi, Ulla
    Research Unit of Sustainable Chemistry, University of Oulu.
    Fabritius, Timo
    Process Metallurgy Research Unit, University of Oulu.
    Use of biomass in integrated steelmaking: Status quo, future needs and comparison to other low-CO2 steel production technologies2018Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 213, s. 384-407Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper provides a fundamental and critical review of biomass application as a reducing agent and fuel in integrated steelmaking. The basis for the review is derived from the current process and product quality requirements that also biomass-derived fuels should fulfill. The availability and characteristics of different sources of biomass are discussed and suitable pretreatment technologies for their upgrading are evaluated. The existing literature concerning biomass application in bio-coke making, blast furnace injection, iron ore sintering and production of carbon composite agglomerates is reviewed and research gaps filled by providing insights and recommendations to the unresolved challenges. Several possibilities to integrate the production of biomass-based reducing agents with existing industrial infrastructures to lower the cost and increase the total efficiency are given. A comparison of technical challenges and CO2 emission reduction potential between biomass-based steelmaking and other emerging technologies to produce low-CO2 steel is made.

  • 48.
    Söderholm, Patrik
    et al.
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Samhällsvetenskap.
    Strömberg, Lars
    Vattenfall AB, Electricity generation.
    A utility-eye view of the CO₂ compliance-decision process in the European power-sector2003Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 75, nr 3/4, s. 183-192Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The purpose of this paper is to provide a utility eye-view of the European power-sector's CO2-compliance decision process under a tradable emissions scheme. The cost analysis indicates that, in the medium term, many utilities are likely to consider options based on traditional power technologies such as converting existing coal-fired capacity to burn gas, extending the lives of nuclear capacity, and replacing old coal-fired plants with more efficient gas- or even coal-fired units. The long-term economic potential of future options is highly uncertain, and utilities are likely to respond to this by maintaining flexibility in fuel choices and avoid large investments that lock them into a specific compliance method before more efficient and cleaner technologies have crystallized. Given the multitude of possible CO2-mitigation options, there is a strong case for emissions trading and for refraining from policies that build on mandatory fuel-requirements, higher rates of capital stock turnover and technology standards.

  • 49.
    Tanaka, Yasuto
    et al.
    Department of Environmental Science and Technology, Tokyo Institute of Technology, Yokohama.
    Mesfun, Sennai
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Umeki, Kentaro
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Toffolo, Andrea
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Tamura, Yutaka
    Department of Environmental Science and Technology, Tokyo Institute of Technology, Yokohama, Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology, 2-12-1 Ookayama.
    Yoshikawa, Kunio
    Department of Environmental Science and Technology, Tokyo Institute of Technology, Yokohama, Tokyo Institute of Technology, Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology.
    Thermodynamic performance of a hybrid power generation system using biomass gasification and concentrated solar thermal processes2015Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 160, s. 664-672Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper describes the investigation of a hybrid power production system from biomass and solar energy. This paper suggests integration through heat exchanger network as a useful approach to obtain the synergy between biomass and solar. Biomass is first gasified in a bubbling fluidized bed (BFB) gasifier, and then syngas is used in a gas turbine. Excess heat exists in this sub-system and concentrated solar thermal process (CSTP) while there is a demand of steam for generating gasifying agent. Steam Rankine cycle exploits the heat created by these thermal streams to generate power while satisfying the steam demands. Thermodynamic performance was analyzed by process modelling with a semi-kinetic model of BFB gasifier and pinch analyses. The composition and temperature of gasifying agent showed some effect on the overall efficiency of the system. Higher overall efficiency of the system was achieved at higher temperature and higher O2 fraction in the O2-steam mixture as gasifying agent. The increase in thermal input from CSTP had positive effect on overall efficiency of the hybrid system until thermal input from CSTP becomes dominant against thermal stream related to the gasifier and the gas turbine.

  • 50.
    Toffolo, Andrea
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Lazzaretto, Andrea
    University of Padova, Department of Industrial Engineering.
    Manente, Giovanni
    University of Padova, Department of Industrial Engineering.
    Paci, Marco
    ENEL Engineering and Innovation, via Andrea Pisano 120, 56126 Pisa.
    A multi-criteria approach for the optimal selection of working fluid and design parameters in Organic Rankine Cycle systems2014Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 121, s. 219-232Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The selection of the cycle configuration, working fluid and operating parameters is crucial for the economic profitability of Organic Rankine Cycle systems using low to medium temperature heat sources. The aim of this paper is to show a method that improves this selection taking into account several criteria at a time: an original thermodynamic optimization procedure of the system configuration and design parameters which explores all possible configurations, the design options around the optimum values of the objective function, an economic modeling technique validated on real cost data, and the consideration of the off-design behavior. The method is applied to comparatively assess the performance of two working fluids, isobutane and R134a, in the temperature interval between 130 and 180 °C. The results show that the optimal cycle configuration is in most cases subcritical for isobutane and supercritical recuperated for R134a. The maximum power output of R134a is higher than isobutane for all the temperatures considered. The analysis of the objective function around the optimum shows the extent of the best range of turbine inlet pressures and enthalpies. These results highlight alternative design conditions to those maximizing the power output which might be preferred for technical and economic reasons.

12 1 - 50 av 72
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