Endre søk
Begrens søket
20212223242526 1101 - 1150 of 1281
RefereraExporteraLink til resultatlisten
Permanent link
Referera
Referensformat
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Treff pr side
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sortering
  • Standard (Relevans)
  • Forfatter A-Ø
  • Forfatter Ø-A
  • Tittel A-Ø
  • Tittel Ø-A
  • Type publikasjon A-Ø
  • Type publikasjon Ø-A
  • Eldste først
  • Nyeste først
  • Skapad (Eldste først)
  • Skapad (Nyeste først)
  • Senast uppdaterad (Eldste først)
  • Senast uppdaterad (Nyeste først)
  • Disputationsdatum (tidligste først)
  • Disputationsdatum (siste først)
  • Standard (Relevans)
  • Forfatter A-Ø
  • Forfatter Ø-A
  • Tittel A-Ø
  • Tittel Ø-A
  • Type publikasjon A-Ø
  • Type publikasjon Ø-A
  • Eldste først
  • Nyeste først
  • Skapad (Eldste først)
  • Skapad (Nyeste først)
  • Senast uppdaterad (Eldste først)
  • Senast uppdaterad (Nyeste først)
  • Disputationsdatum (tidligste først)
  • Disputationsdatum (siste først)
Merk
Maxantalet träffar du kan exportera från sökgränssnittet är 250. Vid större uttag använd dig av utsökningar.
  • 1101.
    Vuorinen, Esa
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Heino, V.
    Tampere University of Technology, Department of Materials Science.
    Ojala, N.
    Tampere University of Technology, Department of Materials Science.
    Haiko, O.
    University of Oulu, Faculty of Technology, Materials Engineering.
    Hedayati, Ali
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Erosive-abrasive wear behavior of carbide-free bainitic and boron steels compared in simulated field conditions2018Inngår i: Proceedings of the Institution of mechanical engineers. Part J, journal of engineering tribology, ISSN 1350-6501, E-ISSN 2041-305X, Vol. 232, nr 1, s. 3-13Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The wear resistance of carbide-free bainitic microstructures have recently shown to be excellent in sliding, sliding-rolling, and erosive-abrasive wear. Boron steels are often an economically favorable alternative for similar applications. In this study, the erosive-abrasive wear performance of the carbide-free bainitic and boron steels with different heat treatments was studied in mining-related conditions. The aim was to compare these steels and to study the microstructural features affecting wear rates. The mining-related condition was simulated with an application oriented wear test method utilizing dry abrasive bed of 8–10 mm granite particles. Different wear mechanisms were found; in boron steels, micro-cutting and micro-ploughing were dominating mechanisms, while in the carbide-free bainitic steels, also impact craters with thin platelets were observed. Moreover, the carbide-free bainitic steels had better wear performance, which can be explained by the different microstructure. The carbide-free bainitic steels had fine ferritic-austenitic microstructure, whereas in boron steels microstructure was martensitic. The level of retained austenite was quite high in the carbide-free bainitic steels and that was one of the factors improving the wear performance of these steels. The hardness gradients with orientation of the deformation zone on the wear surfaces were one of the main affecting factors as well. Smoother work hardened hardness profiles were considered beneficial in these erosive-abrasive wear conditions.

  • 1102.
    Vuorinen, Esa
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Hosseini, Nazanin
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Hedayati, Ali
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Kornacker, Eva
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik.
    Fernandez, Maria Teresa
    CIDAUT Foundation, Boecillo, Spain.
    Sanz, Javier
    CIDAUT Foundation, Boecillo, Spain.
    Gonzalez, Manuel I.
    CIDAUT Foundation, Boecillo, Spain.
    Cañibano, Esteban
    CIDAUT Foundation, Boecillo, Spain.
    Mechanical and microstructural evaluation of high performancesteel (S700MC) for road restraint systems2019Inngår i: Engineering Failure Analysis, ISSN 1350-6307, E-ISSN 1873-1961Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The suitability of using high performance steel (S700MC) for road restraint systems (RRS) under very high containment level was evaluated in this study. To investigate the influence of the crash on the mechanical behaviour of the steel, different test pieces were tested by tensile and hardness testing, and examined by scanning electron microscopy (SEM). The tensile test results of S700MC showed a noticeable increase in yield strength at 0.2% elongation (Rp0.2) from 744 to 935 MPa, and ultimate tensile strength (UTS) from 810 to 1017 MPa, before and after crash tests (BC and AC, respectively). S700MC showed ~9% lower elongation at fracture value in comparison with S275JR and S355JR steels. Besides, fracture toughness, was significantly higher for S700MC (133 and 148 MJ/m3 for BC and AC, respectively) compared to conventional mild steels (108–118 MJ/m3). Microstructural observations of head-part of all S700MC samples revealed equi-axed grains. The fracture surface of tensile tested samples before crash, showed elongated grains accompanied by pore formation. Among after crash samples, one test piece showed intergranular cracks while no intergranular cracks were observed for the other crashed pieces which resulted in the lower Rp0.2 (813 MPa) and UTS strength (847 MPa) and fracture toughness (125 MJ/m3). The results showed that although RRS manufactured with S700MC undergoes severe mechanical deformation, the risk of brittle fracture is very low and this is beneficial from industrial as well as social point of view.

  • 1103.
    Wagner, David R.
    et al.
    Thermochemical Energy Conversion Laboratory, Department of Applied Physics and Electronics, Umeå University.
    Holmgren, Per
    Thermochemical Energy Conversion Laboratory, Department of Applied Physics and Electronics, Umeå University.
    Skoglund, Nils
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap. Thermochemical Energy Conversion Laboratory, Department of Applied Physics and Electronics, Umeå University.
    Broström, Markus
    Thermochemical Energy Conversion Laboratory, Department of Applied Physics and Electronics, Umeå University.
    Design and validation of an advanced entrained flow reactor system for studies of rapid solid biomass fuel particle conversion and ash formation reactions2018Inngår i: Review of Scientific Instruments, ISSN 0034-6748, E-ISSN 1089-7623, Vol. 89, nr 6, artikkel-id 065101Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The design and validation of a newly commissioned entrained flow reactor is described in the present paper. The reactor was designed for advanced studies of fuel conversion and ash formation in powder flames, and the capabilities of the reactor were experimentally validated using two different solid biomass fuels. The drop tube geometry was equipped with a flat flame burner to heat and support the powder flame, optical access ports, a particle image velocimetry (PIV) system for in situ conversion monitoring, and probes for extraction of gases and particulate matter. A detailed description of the system is provided based on simulations and measurements, establishing the detailed temperature distribution and gas flow profiles. Mass balance closures of approximately 98% were achieved by combining gas analysis and particle extraction. Biomass fuel particles were successfully tracked using shadow imaging PIV, and the resulting data were used to determine the size, shape, velocity, and residence time of converting particles. Successful extractive sampling of coarse and fine particles during combustion while retaining their morphology was demonstrated, and it opens up for detailed time resolved studies of rapid ash transformation reactions; in the validation experiments, clear and systematic fractionation trends for K, Cl, S, and Si were observed for the two fuels tested. The combination of in situ access, accurate residence time estimations, and precise particle sampling for subsequent chemical analysis allows for a wide range of future studies, with implications and possibilities discussed in the paper.

  • 1104.
    Wagner, Katharina
    et al.
    Bioenergy 2020+ GmbH, Güssing, Austria.Institute of Chemical, Environmental & Bioscience Engineering, TU Wien, Vienna, Austria.
    Häggström, Gustav
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Mauerhofer, Anna Magdalena
    Institute of Chemical, Environmental & Bioscience Engineering, TU Wien, Vienna, Austria.
    Kuba, Matthias
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap. Bioenergy 2020+ GmbH, Güssing, Austria. Institute of Chemical, Environmental & Bioscience Engineering, TU Wien, Vienna, Austria.Thermochemical Energy Conversion Laboratory, Department of Applied Physics and Electronics, Umeå University, Umeå, Sweden .
    Skoglund, Nils
    Thermochemical Energy Conversion Laboratory, Department of Applied Physics and Electronics, Umeå University, Umeå, Sweden.
    Öhman, Marcus
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Hofbauer, Hermann
    Institute of Chemical, Environmental & Bioscience Engineering, TU Wien, Vienna, Austria.
    Layer formation on K-feldspar in fluidized bed combustion and gasification of bark and chicken manure2019Inngår i: Biomass and Bioenergy, ISSN 0961-9534, E-ISSN 1873-2909, Vol. 127, artikkel-id 105251Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Understanding layer formation on bed materials used in fluidized beds is a key step for advances in the application of alternative fuels. Layers can be responsible for agglomeration-caused shut-downs but they can also improve the gas composition in fluidized bed gasification. Layers were observed on K-feldspar (KAlSi3O8) impurities originating from the combined heat and power plant Senden which applies the dual fluidized bed (DFB) steam gasification technology. Pure K-feldspar was therefore considered as alternative bed material in DFB steam gasification. Focusing on the interactions between fuel ash and bed material, K-feldspar was tested in combustion and DFB steam gasification atmospheres using different fuels, namely Ca-rich bark, Ca- and P-rich chicken manure, and an admixture of chicken manure to bark. The bed particle layers formed on the bed material surface were characterized using combined scanning electron microscopy and energy-dispersive X-ray spectroscopy; area mappings and line scans were carried out for all samples. The obtained data show no essential influence of operational mode on the layer-formation process. During the combustion and DFB steam gasification of Ca-rich bark, a layer rich in Ca formed while K was diffusing out of the layer. The use of Ca- and P-rich chicken manure inhibited the diffusion of K, and a layer rich in Ca and P formed. The addition of P to bark via chicken manure also changed the underlying layer-formation processes to reflect the same processes as observed for pure chicken manure.

  • 1105.
    Wagner, Katharina
    et al.
    Bioenergy 2020+ GmbH,Vienna, Austria. Institute of Chemical, Environmental & Bioscience Engineering, Technische Universität Wien, Vienna, Austria.
    Häggström, Gustav
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Skoglund, Nils
    Bioenergy 2020+ GmbH,Vienna, Austria. Institute of Chemical, Environmental & Bioscience Engineering, Technische Universität Wien, Vienna, Austria.Thermochemical Energy Conversion Laboratory, Umeå University,Umeå, Sweden.
    Priscak, Juraj
    Bioenergy 2020+ GmbH,Vienna, Austria. Institute of Chemical, Environmental & Bioscience Engineering, Technische Universität Wien, Vienna, Austria.
    Kuba, Matthias
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap. Bioenergy 2020+ GmbH,Vienna, Austria. Institute of Chemical, Environmental & Bioscience Engineering, Technische Universität Wien, Vienna, Austria.Thermochemical Energy Conversion Laboratory, Umeå University, Umeå, Sweden.
    Öhman, Marcus
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Hofbauer, Hermann
    Institute of Chemical, Environmental & Bioscience Engineering, Technische Universität Wien, Vienna, Austria.
    Layer formation mechanism of K-feldspar in bubbling fluidized bed combustion of phosphorus-lean and phosphorus-rich residual biomass2019Inngår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 248, s. 545-554Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The use of phosphorus-rich fuels in fluidized bed combustion is one probable way to support both heat and power production and phosphorus recovery. Ash is accumulated in the bed during combustion and interacts with the bed material to form layers and/or agglomerates, possibly removing phosphorus from the bed ash fraction. To further deepen the knowledge about the difference in the mechanisms behind the ash chemistry of phosphorus-lean and phosphorus-rich fuels, experiments in a 5 kW bench-scale-fluidized bed test-rig with K-feldspar as the bed material were conducted with bark, wheat straw, chicken manure, and chicken manure admixtures to bark and straw. Bed material samples were collected and studied for layer formation and agglomeration phenomena by scanning electron microscopy combined with energy dispersive X-ray spectrometry. The admixture of phosphorus-rich chicken manure to bark changed the layer formation mechanism, shifting the chemistry to the formation of phosphates rather than silicates. The admixture of chicken manure to straw reduced the ash melting and agglomeration risk, making it possible to increase the time until defluidization of the fluidized bed occurred. The results also highlight that an increased ash content does not necessarily lead to more ash melting related problems if the ash melting temperature is high enough.

  • 1106.
    Wagner, Katharina
    et al.
    Bioenergy 2020+ GmbH.
    Kuba, Mathias
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap. Bioenergy 2020+ GmbH.
    Häggström, Gustav
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Skoglund, Nils
    Thermochemical Energy Conversion Laboratory, Department of Applied Physics and Electronics, Umeå University.
    Öhman, Marcus
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Hofbauer, Hermann
    Institute of Chemical, Environmental & Bioscience Engineering, TU Wien.
    Influence of phosphorus on the layer formation on k-feldspar during fluidized bed combustion and gasification2018Inngår i: European biomass conference and exhibition proceedings, E-ISSN 2282-5819, Vol. 26thEUBCE, s. 486-492Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Today, mainly wood-based feedstocks are used in thermo-chemical biomass conversion since they have a comparably high heating value and contain a small amount of ash. Fluidized beds allow a greater variety of fuels to be used, since they are rather flexible regarding their fuel input. The use of biogenic waste streams (chicken manure, horse manure, etc.) and sewage sludge would not only increase the fuel diversity in fluidized beds but might also enhance the usability of side products. The contained essential nutrients like phosphorus, potassium, calcium, etc. in these fuels are enriched in the ash after thermochemical conversion. Thus, in the near future it may be possible to apply this ash as secondary resource for fertilizer. Especially the recovery of phosphorus is of importance due to the imminent phosphorus scarcity. Due to its tendency to react with ash forming elements in fuels, phosphorus influences the ash chemistry severely. Especially the agglomeration and layer formation on bed materials during biomass combustion and gasification is highly dependent on the predominant ash forming elements. Phosphorus therefore has a significant impact on those mechanisms. Until now, the behavior of phosphorus-rich fuels in fluidized beds has not been studied in much detail. To develop a basic understanding of the behavior, phosphorus-rich feedstock was combusted in a bench-scale fluidized bed reactor. Ash layers on bed particles, which were formed during these experiments, were studied and compared to results with phosphorus-lean fuels. Furthermore, layer formation of phosphorus-rich and phosphorus-lean fuels from dual fluid bed gasification were compared to those from fluidized bed combustion. The studied layers on bed materials showed significant amounts of phosphorus. The data also indicates a change in layer formation as soon as phosphorus is present. An increased catalytic activity due ash-layer formation was observed for both phosphorus-rich and phosphorus-lean feedstock, independent from the presence of phosphorus in the ash layer

  • 1107.
    Wahlberg, Mats
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Rönnberg, Sarah
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Case study on electrical conductivity in wood poles2017Rapport (Annet vitenskapelig)
  • 1108.
    Wahlberg, Mats
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Rönnberg, Sarah
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Currents in power line wood poles2011Inngår i: Proceedings of CIRED 21st International Conference on Electricity Distribution, 2011, artikkel-id 0347Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Over the last few years some rather severe problems have arisen for poles used to support overhead power lines. A wooden power line pole is assumed to be a good electric insulator because of the basic properties of wood with its porous structure and cellulose compounds forming the major part of the cell walls. A fault during which an insulator is broken or a phase conductor has loosened, normally poses no danger. In rare cases a fire has started, but this has not been seen as a sufficiently dangerous situation to change maintenance practice. However, it has been noticed that under certain circumstances such poles can get conductive enough to result in hazardous or even lethal current for power line maintenance workers climbing the pole.

  • 1109.
    Wahlberg, Mats
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Rönnberg, Sarah
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Currents in power line wood poles: a measuring method2010Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Recently a maintenance worker in Sweden was killed when climbing into a wood pole supporting an 11-kV overhead line. The investigating done afterwards raised the suspicion that a current flowed through the pole was sufficient to kill a person. Due to a broken insulator one of the phases of the 11-kV line had been resting on the metal crossbar. This accident triggered an investigation in order to determine if power line wood poles can conduct current and if so, whether this current can be sufficient to injure a maintenance worker climbing into the pole. The study has been made at the 11 kV level on a pole while a live wire was resting on the metal cross arm as would be the case if the insulator had broken. A proposal for a measuring method has been developed in order to determine under what conditions climbing should be prohibited. In Sweden the use of wood poles as part of 11 kV overhead lines is fairly common. A three phase system is used to distribute 11 kV, one wire for each phase, and the three wires are supported by insulators mounted on a horizontal metal (or wood) cross arm. The poles are treated with some kind of preservative to protect the wood from rot and insects. Three kinds of preservatives are commonly used in Sweden: arsenic, creosote and salt. In this study eight poles with different preservative and age varying from 50 years old to brand new have been examined in a realistic environment. The measurements presented in this paper support the earlier suspicion that a wood pole used for distributing power can conduct current if a fault occurs and a live wire comes in contact with the metal cross arm. It also shows that the current through a parallel, not connected to earth, resistor (i.e. a human climbing the pole) can reach potentially harmful amplitudes. Three main variables that affect the electrical characteristics of the pole have been identified: the preservation of the wood; the environmental temperature; and the humidity of the surroundings. There are however other variables that can have an impact on the conductivity of the pole for example how the pole was dried before preservation.

  • 1110.
    Wahlberg, Mats
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Rönnberg, Sarah
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Design of power lines poles that will be safe even when a phase has come in contact with crossarm.2014Konferansepaper (Fagfellevurdert)
  • 1111.
    Wang, C.
    et al.
    Swerea MEFOS AB.
    Larsson, Mikael
    Yan, Jinyue
    Dahl, Jan
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    CO2 emission reduction in the steel industry by using emission trading programs2007Inngår i: International Journal of Green Energy, ISSN 1543-5075, E-ISSN 1543-5083, Vol. 4, nr 5, s. 505-518Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The implementation of the EU Emission Trading Scheme ( ETS) started on January 1(st) 2005 according to national plans for allocating emissions rights. The steel industry is one of the industrial sectors included in this scheme. The objective of this paper is to investigate and evaluate the optimum solution( s) for European steel plants to meet their emission allowance with low reduction cost. An optimization model based on a Swedish steel plant is developed and used. Three scenarios were created in the model, i. e., internal changes within the steel plant, EU ETS, and the Kyoto Protocol's clean development mechanism ( CDM). For the last scenario, China was selected as a country of the non- Annex I Party for the emission trading by CDM. The modeling results show that the studied plant will face an emission gap between allowed and calculated emissions in the near future. Compared to EU ETS, the implementation of CDM projects will make the plant reduce CO2 emissions at a lower cost. The internal changes within the plant will also play an important role for the solution of low abatement cost. The model developed could serve as a benchmark for the future emission trading simulation's purpose within the European steel industry.

  • 1112.
    Wang, Chaun
    et al.
    Swerea MEFOS.
    Suopajärvi, Hannu
    University of Oulu.
    Ng, Ka Wing
    Natural Resources Canada, CanmetENERGY.
    Chinedu, Nwachukwu
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Elisabeth, Wetterlund
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Research development on utilizing biomass in the blast furnace for CO2 emission reduction: Experiences from Nordic countries and Canada2018Konferansepaper (Annet vitenskapelig)
  • 1113.
    Wang, Chuan
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Climate change mitigation through CDM: bioenergy technology and energy efficiency in the steel industry2005Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Climate change is one of the most significant challenges to sustainable development facing the international community. Increased attention has been given by industries and governments from both industrialized and developing countries to reduce greenhouse gas (GHG) emissions through the clean development mechanism (CDM), one of the Kyoto Protocol's (KP) flexible mechanisms. China is the biggest developing country in the world. The energy demands in China are increasing quickly with its rapid economic growth. However, low energy efficiency and coal-dominated energy make China the world's second largest CO2 emitter behind the United States. Sweden, an industrialized country with high-energy efficiency and a good renewable energy system, shows its leadership in international cooperation and competence on the climate change issues. Sweden has already declared its desire to contribute to making KP's CDM work and become an effective instrument in the work on international climate change mitigation. It is of great interest to investigate the possibilities and the potential of GHG emission reduction through CDM. The objective of the work, considering the mitigating greenhouse gases in a global perspective, is to study how to introduce CDM with technology transfer between Sweden and China. This study provides illustrative examples of opportunities and benefits as well as revealing the problems associated with this mechanism. Two research areas, i.e. bioenergy technology and energy efficiency in the steel industry, are studied in this thesis. Regarding bioenergy technology, with consideration of technology status and biomass resource differences between Sweden and China, this study explores the potential and benefits of implementing Swedish advanced bioenergy technologies in China. A case study further shows that it is possible to produce and utilize wood pellets in China by using Swedish technology under CDM. As for the energy efficiency in the steel industry, an optimization model was developed to simulate CO2 emissions. The modeling results show that CO2 could be reduced at a low cost by implementing CDM projects between Swedish and Chinese steel plants.

  • 1114.
    Wang, Chuan
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Possibilities of CO2 emission reduction: process integration analysis and carbon trading schemes2007Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Climate change is one of the greatest challenges faced by today's society. With more evidence from scientists, the need to manage greenhouse gas emissions has been increasing in response to international climate change negotiations. With the aid of the Kyoto Protocol's entry into force in February 2005, more efforts on greenhouse gas emission reduction can be expected from nations. In this thesis, possibilities of reducing carbon dioxide emission in Sweden have been analysed: via the internal abatement from domestic efforts; and through international collaboration with the aid of carbon trading schemes. For the former, the Swedish steel industry was chosen and the Process Integration (PI) method was applied to analyse possibilities of CO2 emission reduction. For the latter, case studies were performed to demonstrate CO2 emission reduction by using Kyoto market mechanisms and EU ETS. A process integration method was developed and used to analyse CO2 emission for the steel industry with consideration of the material and energy system. This model was initially designed based on a specific steel plant. However, the model can be used to analyse other steel plants with different processes, either for the whole steel process system or some sub-systems. The modelling work on optimising residue material flows and ferrous burden materials use for the BF-BOF system was focused on analysing CO2 emission reduction. The model covering the carbon trading systems shows that internal changes and the Kyoto CDM mechanism will both contribute to help steel plants to meet their emission allowance and future reduction commitments. The carbon trading schemes will play a critical part in future efforts against climate change since they can offer lower cost. CDM is the only operative Kyoto mechanism at the moment, and it will probably be the largest carbon trading market. In addition, it is the only mechanism through which the developing countries have been involved in the climate change mitigation arena. The Swedish government has already declared its desire to contribute to making CDM work and become an effective instrument in work on the international climate. Sweden will keep a leading position in the bioenergy technology field by implementing more CDM projects and will also gain more experience of international collaboration related to the CDM. The calculated potential reduction of CO2 emission by using Swedish bioenergy technologies can be used as a guideline to develop CDM projects in developing countries. Two case studies of bioenergy CDM projects demonstrate how Sweden can reduce CO2 emission via CDM. In summary, it is possible to reduce the industrial CO2 emissions at lower cost through carbon trading schemes. However, it is important to preserve the competitiveness of industry. Therefore, domestic actions/internal abatement should be encouraged since they can further improve the efficiency and promote the discovery of new technologies for creating a more sustainable energy supply both from an economic and an environmental point of view.

  • 1115. Wang, Chuan
    et al.
    Chen, Shuming
    National Bio Energy Co., Ltd..
    Lundgren, Joakim
    Dahl, Jan
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Technical and economic barriers for utilization of straw-fired co-generation in China2007Inngår i: From Research to Market Deployment: 15th European Biomass Conference & Exhibition ; proceedings of the international conference held in Berlin, Germany, 7 - 11 May 2007 / [ed] K. Maniatis, Florence: ETA - Renewable Energies , 2007Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In order to promote the development and utilization of renewable energy, improve the energy structure, diversify energy supplies, safeguard energy security, protect the environment, and realize the sustainable development of the economy and society, the Chinese government is now paying more attention to develop and utilizing the renewable energy in China. The available biomass resources (e.g. straw and crop residues) for energy use in China are abundant. As one bioenergy technology, straw-fired cogeneration technology can provide clean energy in rural areas in China. In recent years, some investors have shown their interests in developing straw-fired cogeneration plants. Some projects are already in the pipeline and the number of projects is expected to increase in the near future. However, there exist technical as well as economic barriers hindering the implementation of straw-fired cogeneration projects. These barriers include 1) feedstock preparation barrier regarding the straw collection, transportation, treatment and storage and less incentives from farmers; 2) some technical and production operation management barriers; 3) over-expected market demands; 4) economic barriers; 5) lack of strong policy support, etc. In this paper, all these barriers have been studied and analyzed. In addition, good management experiences of straw-fired cogeneration plants from European countries have been reviewed as a comparison with those plants in China and based on that, some recommendations have been made to improve the implementation conditions for straw-fired cogeneration projects in China.

  • 1116. Wang, Chuan
    et al.
    Johnsson, A.
    Swerea MEFOS AB.
    Wikström, Jan-Olov
    Engdahl, J.
    SSAB Tunnplåt AB.
    Asp, Björn
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Dahl, Jan
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Modeling analysis on potential energy saving in a Swedish rolling mill2011Konferansepaper (Fagfellevurdert)
  • 1117.
    Wang, Chuan
    et al.
    Swerea MEFOS AB, Center for Process Integration in Steelmaking, Swerea MEFOS, Luleå.
    Larsson, Mikael
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Lövgren, Jonas
    SSAB EMEA, Luleå.
    Nilsson, Leif
    SSAB EMEA, Luleå.
    Mellin, Pelle
    Division of Energy and Furnace Technology, KTH Royal Institute of Technology.
    Yang, Weihon
    KTH Royal Institue of Technology, Division of Energy and Furnace Technology.
    Salman, Hassan
    Energy Technology Centre, Piteå, Luleå tekniska universitet, Sveaskog.
    Hultgren, Anders
    Injection of Solid Biomass Products into the Blast Furnace and its Potential Effects on an Integrated Steel Plant2014Inngår i: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 61, s. 2184-2187Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This study is to investigate different types of biomass products’ injection into the blast furnace (BF) to replace pulverized coal injection (PCI). The biomass products covered in the study are charcoal, torrefied material and wood pellets on the basis of Swedish forests. The modelling work has been performed in a specialized BF model. The modelling results show that charcoal has the significant effects on the BF operation. PCI can be replaced fully by charcoal, and only limited amount of torrefied material and wood pellets can be injected into BF. For the studied BF, the annual CO2 emission reduction potential from the replaced amount of PCI when injecting charcoal, torrefied material and wood pellets are about 1140 kton, 260 kton and 230 kton, respectively. In addition, a possible energy saving can be achieved for charcoal injection. A slightly higher P content in the hot metal may occur when injecting torrefied material

  • 1118. Wang, Chuan
    et al.
    Larsson, Mikael
    Ryman, Christer
    Grip, Carl-Erik
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Wikström, Jan-Olov
    A model study on CO2 emission reduction in integrated steelmaking by optimisation methods2007Inngår i: 3rd International Green Energy Conference: Proceedings of IGEC-III, Västerås: Mälardalens högskola , 2007Konferansepaper (Annet vitenskapelig)
  • 1119. Wang, Chuan
    et al.
    Larsson, Mikael
    Ryman, Christer
    Grip, Carl-Erik
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Wikström, Jan-Olov
    Johnsson, Andreas
    Swerea MEFOS AB.
    Engdahl, Jonas
    SSAB Tunnplåt AB.
    A model on CO2 emission reduction in integrated steelmaking by optimization methods2008Inngår i: International journal of energy research (Print), ISSN 0363-907X, E-ISSN 1099-114X, Vol. 32, nr 12, s. 1092-1106Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The iron and steel industry is a large energy user in the manufacturing sector. Carbon dioxide from the steel industry accounts for about 5-7% of the total anthropogenic CO2 emission. Concerns about energy consumption and climate change have been growing on the sustainability agenda of the steel industry. The CO2 emission will be heavily influenced with increasing steel production in the world. It is of great interest to evaluate and decrease the specific CO2 emission and to find out feasible solutions for its reduction. In this work, a process integration method focusing on the integrated steel plant system has been applied. In this paper, an optimization model, which can be used to evaluate CO2 emission for the integrated steel plant system, is presented. Two application cases of analysing CO2 emission reduction possibilities are included in the paper. Furthermore, the possibility to apply the model for a specific integrated steel plant has been discussed. The research work on the optimization of energy and CO2 emission has shown that it is possible to create a combined optimization tool that is powerful to assess the system performance from several aspects for the steel plant.

  • 1120. Wang, Chuan
    et al.
    Larsson, Mikael
    Yan, Jinyue
    Dahl, Jan
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Impact on CO2 emission allowance of EU emission trading Scheme (ETS) in a Swedish steel plant by clean development mechanism (CDM)2005Inngår i: Proceedings, International Green Energy Conference, 2005Konferansepaper (Fagfellevurdert)
  • 1121. Wang, Chuan
    et al.
    Lundgren, Joakim
    Hermansson, Roger
    Dahl, Jan
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Straw-fired congeneration as a possibility to provide clean energy in rural areas in China2005Inngår i: Biomass for energy, industry and climate protection: 14th European Biomass Conference & Exhibition ; proceedings of the international conference held in Paris, France, 17 - 21 October 2005, Florence: ETA - Renewable Energies , 2005Konferansepaper (Fagfellevurdert)
  • 1122.
    Wang, Chuan
    et al.
    Swerea MEFOS AB, Center for Process Integration in Steelmaking, Swerea MEFOS, Luleå.
    Mellin, Pelle
    Division of Energy and Furnace Technology, KTH Royal Institute of Technology.
    Lövgren, Jonas
    SSAB EMEA, Luleå, SSAB Europe.
    Nilsson, Leif
    SSAB EMEA, Luleå, SSAB Europe.
    Yang, Weihong
    Division of Energy and Furnace Technology, KTH Royal Institute of Technology.
    Salman, Hassan
    Energy Technology Centre, Piteå, Luleå tekniska universitet, Sveaskog.
    Hultgren, Anders
    SCA Energy, 851 88 Sundsvall.
    Larsson, Mikael
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Biomass as blast furnace injectant: Considering availability, pretreatment and deployment in the Swedish steel industry2015Inngår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 102, s. 217-226Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We have investigated and modeled the injection of biomass into blast furnaces (BF), in place of pulverized coal (PC) from fossil sources. This is the easiest way to reduce CO2 emissions, beyond efficiency-improvements. The considered biomass is either pelletized, torrefied or pyrolyzed. It gives us three cases where we have calculated the maximum replacement ratio for each. It was found that charcoal from pyrolysis can fully replace PC, while torrefied material and pelletized wood can replace 22.8% and 20.0% respectively, by weight.Our energy and mass balance model (MASMOD), with metallurgical sub-models for each zone, further indicates that (1) more Blast Furnace Gas (BFG) will be generated resulting in reduced fuel consumption in an integrated plant, (2) lower need of limestone can be expected, (3) lower amount of generated slag as well, and (4) reduced fuel consumption for heating the hot blast is anticipated. Overall, substantial energy savings are possible, which is one of the main findings in this paper.Due to the high usage of PC in Sweden, large amounts of biomass is required if full substitution by charcoal is pursued (6.19 TWh/y). But according to our study, it is likely available in the long term for the blast furnace designated M3 (located in Luleå).Finally, over a year with almost fully used production capacity (2008 used as reference), a 28.1% reduction in on-site emissions is possible by using charcoal. Torrefied material and wood pellets can reduce the emissions by 6.4% and 5.7% respectively. The complete replacement of PC in BF M3 can reduce 17.3% of the total emissions from the Swedish steel industry.

  • 1123.
    Wang, Chuan
    et al.
    Swerea MEFOS AB, Center for Process Integration in Steelmaking, Swerea MEFOS, Luleå.
    Mellin, Pelle
    Division of Energy and Furnace Technology, KTH Royal Institute of Technology.
    Nilsson, Leif
    SSAB EMEA, Luleå.
    Lövgren, Jonas
    SSAB EMEA, Luleå.
    Wikström, Jan Olov
    Swerea MEFOS AB.
    Larsson, Mikael
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Injecting different types of biomass products to the blast furnace and their impacts on the CO2 emission reduction2015Inngår i: AISTech 2015: Proceedings of the Iron & Steel Technology Conference : 4-7 May 2015, Cleveland, Ohio, U.S.A / [ed] Ronald E Ashburn, Warrendale, PA: Association for Iron & Steel Technology , 2015, s. 1525-1535Konferansepaper (Fagfellevurdert)
  • 1124. Wang, Chuan
    et al.
    Nordgren, Samuel
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Lindblom, Bo
    LKAB.
    Savonen, Stefan
    LKAB.
    Hansson, Robert
    LKAB.
    Integrated conceptual design of heating system at a Swedish mining company2009Inngår i: Pres09 - 12th Conference Process Integration, Modelling and Optimisation for Energy Saving and Pollution Reduction / [ed] Jiri Klemeš, AIDIC Servizi S.r.l. , 2009, s. 129-134Konferansepaper (Fagfellevurdert)
    Abstract [en]

    LKAB Malmberget is a Swedish mining site located at Malmberget, Sweden. Seven boiler centers are located on north part of Malmberget. There are no connections in between these boiler centers, meaning that it is a decentralized heating system. The heat generated is to heat up buildings and for mine ventilation mainly during the cold periods. The heat is mainly provided from electric and oil boilers. However, most boilers under use are over 20 years old, and it is time to retrofit the boiler system and infrastructure. The purpose of this work is to design and optimize the heating system by the integrated concept. An optimization model based on the mixed integer linear programming (MlLP) has been developed to minimize the total heat production cost, including operation cost and investment cost. The model can be used to calculate how a given heat demand can be satisfied at the lowest possible cost. Four different technical options have been considered in a new centralized heating system. On the basis of data input and assumptions, modeling results indicate that a lower cost could be achieved when a waste heat recovery boiler is installed at the old pelletization plant to recover sensible heat from flue gas. This will lead to a remarkable electricity saving (around 70% saving) compared to the reference case. It has also been noticed that in the optimized cases, oil boilers should not be operated due to a higher price compared to electricity, and by estimation an annual reduction of 3000 ton CO2 and 4.5 ton NOx could be achieved.

  • 1125. Wang, Chuan
    et al.
    Nordgren, Samuel
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Lindblom, Bo
    LKAB.
    Savonen, Stefan
    LKAB.
    Hedpalm, Theresa
    LKAB.
    Larsson, Mikael
    Hansson, Robert
    LKAB.
    Conceptual design of an integrated heating system at LKAB Malmberget with consideration of social-environmental damage costs2010Inngår i: Journal of Cleaner Production, ISSN 0959-6526, E-ISSN 1879-1786, Vol. 18, nr 9, s. 944-951Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    LKAB Malmberget is a Swedish mining site located at Malmberget, Sweden. Seven boiler centers are located in the north part of Malmberget. There are no connections in between these boiler centers, meaning that it is a decentralized heating system. The heat generated is used to heat up buildings and for mine ventilation air mainly during the cold periods. The heat is mainly provided from electric and oil boilers. However, most boilers under use are over 20 years old, and it is time to retrofit the boiler system and infrastructure. The purpose of this work is to design and optimize the heating system by introducing an integrated concept to minimize the heat production cost.An optimization model based on the mixed integer linear programming (MILP) has been developed. Several technical options have been considered in a new centralized heating system. The optimization principle is based on two kinds of perspectives: current price and external costs. With consideration of environmental and health damage from society concerns point of view, instead of environmental taxes in the current price perspective, the monetary values of externalities due to pollutants such as CO2, NOx, SO2 and particulates emitted from the heating system are included. On the basis of data input and assumptions, modeling results indicate that a lower cost could be achieved when a waste heat recovery boiler is installed at the older pelletization plant to recover sensible heat from flue gas. This technical option is the best solution or at least contributes to the best solution in all optimization results. Including the externality cost is useful for making fair evaluation of the social-environmental impacts of the alternatives.

  • 1126. Wang, Chuan
    et al.
    Ryman, Christer
    Dahl, Jan
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Potential CO2 emission reduction for BF-BOF steelmaking based on optimised use of ferrous burden materials2009Inngår i: International Journal of Greenhouse Gas Control, ISSN 1750-5836, E-ISSN 1878-0148, Vol. 3, nr 1, s. 29-38Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Currently, the blast furnace (BF) to basic oxygen furnace (BOF) is the dominant steel production route in the steel industry. The direct CO2 emission in this process system exceeds 1 t of CO2/t of crude steel produced. Different ferrous burden materials, for instance iron ore and scrap, can be used in various proportions in this steelmaking route. This paper analyses how energy use, conversion costs, and CO2 emissions can be influenced by the use of different ferrous burden materials when producing crude steel. An optimisation mixed integer linear programming (MILP) model has been applied for analysis. By the use of the optimisation model, it is possible to highlight some issues of special importance, such as best practices to increase production at low conversion cost, or best practices to increase production at low CO2 emission. It is found out that more benefits will be gained when using the system-oriented analysis to the steelmaking process. Furthermore, a comprehensive view of the trade-offs between the objectives of Cost and CO2 can provide useful information for decision makers to generate strategies under the future emission trading.

  • 1127.
    Wang, Chuan
    et al.
    Center for Process Integration in Steelmaking, Swerea MEFOS, Luleå.
    Sandberg, Johan
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Larsson, Mikael
    Swerea MEFOS AB.
    Analysis of oxygen enrichment and its potential influences on the energy system in an integrated steel plant using a new solution space based optimization approach2011Inngår i: PRES'11: 14th Conference on Process Integration, Modelling and Optimisation for Energy Saving and Pollution Reduction, AIDIC Servizi S.r.l. , 2011, Vol. 25, s. 87-92Konferansepaper (Fagfellevurdert)
    Abstract [en]

    With oxygen enrichment in hot stoves the high calorific coke oven gas can be saved due to the possibility of using lower calorific gases which enables replacement of other imported fuels such as oil or LPG. The application of increased oxygen use in hot stoves or increased O2 in blast, will also potentially lead to lower coke rate. Central to the performance in system optimisation is the ability to analyse and properly describe the system variations. The demand for coke oven gas is depending on both internal operation logistics but it also has outdoor temperature dependence through a heat and power plant producing district heat to the community. An analysis of the influence of increased oxygen enrichment on the entire energy system has been carried out by use of an optimization model. A method of achieving a high time resolution in MILP optimisation is applied in the analysis. Different strategies have been suggested for minimum energy consumption at the studied steel plant and the nearby CHP plant.

  • 1128.
    Wang, Chuan
    et al.
    Luleå tekniska universitet, Extern. Swera MEFOS.
    Suopajärvi, Hannu
    Luleå tekniska universitet, Extern. University of Oulu.
    Ng, Ka Wing
    Luleå tekniska universitet, Extern. Natural Reseource Canada, CanmetENERGY.
    Nwachukwu, Chinedu
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Wetterlund, Elisabeth
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    RESEARCH DEVELOPMENT ON UTILIZING BIOMASS IN THE BLAST FURNACE FOR CO2 EMISSION REDUCTION: EXPERIENCES FROM NORDIC COUNTRIES AND CANADA2018Konferansepaper (Annet vitenskapelig)
  • 1129.
    Wang, Chuan
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Yan, Jinyue
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Feasibility analysis of wood pellets production and utilization in China as a substitute for coal2005Inngår i: International Journal of Green Energy, ISSN 1543-5075, E-ISSN 1543-5083, Vol. 2, nr 1, s. 91-107Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Wood pellets are regarded as one of the substitutes for fossil fuels like coal and oil for heating and co-generation. Wood pellets are a successful example of market penetration of renewable energy in some countries in Europe, e.g., Sweden. An analysis process is proposed in this paper and used to conduct a techno-economic assessment of wood pellets production and applications in some areas in China with the consideration of technology transfer from Sweden by examining their market competitiveness with coal in these areas. Financial indices such as net present value (NPV), internal return rate (IRR) and year-to-positive cash flow are calculated to investigate the profitability of the technology transfer. Four locations of applications in China have been considered as case studies. The result indicates that in the market-only-based scenario, wood pellets production will not be profitable in all selected areas. New scenarios from the analysis process show that reducing investment and increasing the amount of bank loan will be helpful to increase the project's profitability in general; adding taxes on coal could be effective, but it depends on Chinese government's future efforts on climate change mitigation; carbon credits on wood pellets through the clean development mechanism (CDM) might make wood pellet projects profitable giving wood pellets a nich-market. The potential global environment benefits of CO2 emission reduction by using wood pellets to replace coal in a 7 MWth coal-fired industrial boiler with a thermal efficiency of 80% and 5000 hours of operation time are also presented.

  • 1130. Wang, Chuan
    et al.
    Zeng, Lei
    Yan, Jinyue
    Lundgren, Joakim
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Potential carbon dioxide emission reduction in China by using Swedish bioenergy technologies2006Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    During recent years, an increased attention has been given by industries and governments from industrialized as well as developing countries to reduce greenhouse gas (GHG) emissions through the clean development mechanism (CDM). As China has increasing demands on bioenergy and Sweden has good practices and competence in developing and utilizing bioenergy technologies, this paper studies the resulting consequence if implementing Swedish bioenergy technologies in China. The potential CO2 emission reduction from each technology in China is studied. A few priority areas for future CDM projects selection by using Swedish technologies are recommended.

  • 1131.
    Wang, Chuan
    et al.
    Swerea MEFOS, Box 812, Luleå.
    Zetterholm, Jonas
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Lundqvist, Magnus
    Swerea MEFOS, Box 812, Luleå.
    Schlimbach, Jürgen
    DK Recycling und Roheisen GmbH.
    Modelling and Analysis of Oxygen Enrichment to Hot Stoves2017Inngår i: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 105, s. 5128-5133Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The paper presents some research work on applying the oxygen enrichment technique to hot stoves that was carried out in one European RFCS project. In the presented work, both theoretical and practical work was studied. A dynamic model was used to investigate the effects of oxygen enrichment on hot stoves’ performance under the condition that only blast furnace gas was used as the fuel gas. The modelling results showed that SOE will enhance the combustion process in hot stoves by increasing hot blast temperature and shortening the on-gas time, which were further verified by industrial trials performed at an iron-making plant. In addition, CFD modelling was performed by simulating different oxygen levels and lance positions at the burner to avoid the hot spot formation during the combustion.

  • 1132.
    Wang, Xin
    et al.
    DNV China.
    Wang, Chuan
    Grip, Carl-Erik
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Dahl, Jan
    Implementation of energy audit in the Chinese steel industry: case studies of integrated steel plants2008Inngår i: SCANMET III: 3rd International Conference on Process Development in Iron and Steelmaking, 8-11 June 2008, Luleå, Sweden, Luleå: MEFOS , 2008, Vol. 1, s. 417-426Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Steel production is one of the energy intensive industries in the world. Energy saving measures are of increasing interest to Chinese steel industry in recent years. One of the technical instruments of energy saving is energy audit. This paper presents the energy audit analysis of integrate steel plants in China as a case study. The analysis is useful to determine the actual consumption, reveal the anomalies and suggest corrective measures. These will provide clear indication on the pattern of energy losses and will aid in decision support for evolution of energy saving measures. The paper will show the achievements of Chinese steel plants during these years of energy saving activities proposed by government and the potential for energy efficient renovation. Some suggestion has been made in order to widely use this analytical diagnostic tool in Chinese steel industry.

  • 1133.
    Wang, Ying
    et al.
    College of Electrical Engineering and Information Technology, Sichuan University.
    Bagheri, Azam
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Xiao, Xian-Xong
    College of Electrical Engineering and Information Technology, Sichuan University.
    Single-Event Characteristics for Voltage Dips in Three-Phase Systems2017Inngår i: IEEE Transactions on Power Delivery, ISSN 0885-8977, E-ISSN 1937-4208, Vol. 32, nr 2, s. 832-840, artikkel-id 7496837Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper compares different methods for voltage-dip characterization. Those methods are based on earlier proposed algorithms for extracting three-phase characteristics (dip type, characteristic voltage, and so-called “PN factor”). The difference between the 12 methods being studied in this paper is in the way in which the time variation of those characteristics is treated to result in single-event characteristics. The methods are applied to 259 measured voltage dips and the performance of the different methods is compared. It is found that small differences in method can result in big difference in results. From the comparison, two methods are selected and recommended for inclusion in international standards.

  • 1134.
    Wang, Ying
    et al.
    College of Electrical Engineering and Information Technology, Sichuan University.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bagheri, Azam
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Xiao, Xian-Xong
    College of Electrical Engineering and Information Technology, Sichuan University.
    Olofsson, Magnus
    Elforsk, Energiforsk AB, Stockholm.
    A quantitative comparison approach for different voltage dip characterization methods2016Inngår i: Electric power systems research, ISSN 0378-7796, E-ISSN 1873-2046, Vol. 133, s. 182-190Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper presents a systematic approach to compare different methods for characterizing voltage dips in a quantitative way. A prediction error is calculated between measured and synthetic dips (reproduced from single-event characteristics for the measured dips) with respect to the way they impact the performance of a generic device. The proposed approach is illustrated by comparing seven different characterization methods and their ability to predict the minimum dc-bus voltage of a three-phase adjustable-speed drive. A generic model of such a drive is used for this. Based in this comparison it is concluded that characterization method for dips in three-phase systems should include unbalance and phase-angle jump.

  • 1135.
    Wang, Ying
    et al.
    College of Electrical Engineering and Information Technology, Sichuan University.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Xiao, X. Y.
    College of Electrical Engineering and Information Technology, Sichuan University.
    Calculation of the phase-angle-jump for voltage dips in three-phase systems2015Inngår i: IEEE Transactions on Power Delivery, ISSN 0885-8977, E-ISSN 1937-4208, Vol. 30, nr 1, s. 480-487, artikkel-id 6899711Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The phase-angle-jump is defined in this paper as another single-event characteristic of voltage dips, besides residual or characteristic voltage and duration. This paper proposes and compares six methods to calculate the phase-angle-jump for measured voltage dips in a three-phase system. This paper also studies the details of the calculation: correcting frequency and transition segments. The six proposed methods have been applied to 235 sets of measured voltage dips and a statistical comparison has been made. It is recommended that two of the methods be included in IEEE Standard 1564 and IEC 61000-4-30.

  • 1136.
    Wang, Ying
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Xiao, X. Y.
    Mitigating the effects due to voltage dips by considering the Process Immunity Time2014Konferansepaper (Fagfellevurdert)
  • 1137.
    Wang, Ying
    et al.
    College of Electrical Engineering and Information Technology, Sichuan University.
    Xiao, Xianyong
    College of Electrical Engineering and Information Technology, Sichuan University.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Challenges in the Calculation methods of Point-on-Wave Characteristics for Voltage Dips2016Inngår i: 2016 17th International Conference on Harmonics and Quality of Power, Piscataway, NJ, 2016, s. 513-517, artikkel-id 7783435Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Point-on-wave (POW) is an important single-event characteristic of voltage dips. Both POW of initiation and of recovery may affect the equipment. POW is important information to accurate evaluate the equipment performance and behavior during a voltage dip. The 'predefined thresholds approach (PTA)' and the 'waveform envelope approach (WEA)' are two approaches to calculate POW. This paper analyzes the challenges of existing POW calculation methods. Some improvement work is suggested to address these challenges

  • 1138.
    Wang, Zhongwei
    et al.
    Department of Electrical and Electronic Engineering, The University of Hong Kong.
    Zhong, Jin
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Procuring and pricing performance-based frequency regulation services in the electricity market2017Inngår i: IET Generation, Transmission & Distribution, ISSN 1751-8687, E-ISSN 1751-8695, Vol. 11, nr 10, s. 2633-2642Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This study presents a market model that procures energy and performance-based regulation services simultaneously considering the participation of energy storage devices. The correlations of energy, regulation capacity, and regulation mileage are explicitly demonstrated. The proposed market model determines the energy schedule of generation units, charging and discharging profiles of energy storage devices, and the schedule of regulation services. Market clearing prices for energy, regulation capacity, and regulation mileage are derived and decomposed through Lagrange multiplier analysis. The relationships between the clearing prices of different market products are analysed. The proposed market model is tested and verified with the IEEE 30-bus system. © The Institution of Engineering and Technology.

  • 1139.
    Wang, Zhongwei
    et al.
    Department of Electrical and Electronic Engineering, The University of Hong Kong.
    Zhong, Jin
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Li, Jianhui
    Guangdong Power Dispatch Centre.
    Design of performance-based frequency regulation market and its implementations in real-time operation2017Inngår i: International Journal of Electrical Power & Energy Systems, ISSN 0142-0615, E-ISSN 1879-3517, Vol. 87, s. 187-197Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The importance of the performance of frequency regulation has already been acknowledged by regulators and Independent System Operators (ISOs). A performance-based frequency regulation market model considering both regulation capacity and regulation mileage constraints is proposed in this paper. In the proposed market, high-performance regulation resources have higher priorities to be selected in the market. Market clearing prices are derived with Lagrange relaxation. The analysis of the components of market clearing prices accurately indicates the correlation between regulation capacity and regulation mileage. To accommodate the proposed regulation market design, AGC allocation algorithm is adjusted based on the market clearing results. The clearing procedure of the market model is demonstrated on an illustrative case. The proposed market design is tested and verified with market simulations and system dynamic simulations. Simulation results are discussed and compared to show the effectiveness of the proposed market design. 

  • 1140.
    Wei, Jiayuan
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Geng, Shiyu
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Sarmad, Shokat
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Hedlund, Jonas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Oksman, Kristiina
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Adsorption of Carbon Dioxide on Cellulose Nanofiber-Based Monolithic Cryogels Impregnated with Acetylated Cellulose Nanocrystals2018Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Nanocellulose materials with large surface area are prospective as substrates to obtain low-carbon-footprint CO2 adsorbents. In this study, ice-templating was conducted to prepare cellulose nanofibers (CNFs) based cryogels with monolithic structure, which can provide a good mass flow during the adsorption process. Furthermore, since acetyl groups have shown relatively high CO2 affinity, cellulose nanocrystals (CNCs) were acetylated and then impregnated into the cryogel to improve its CO2 capacity. Meanwhile, different amounts of cellulose acetate (CA) were impregnated and characterized as references. The success of the acetylation of CNCs was confirmed by Fourier-transform infrared spectroscopy (FTIR) and the degree of substitution was determined by titration. Results from the scanning electron microscopy (SEM) demonstrated that the monolithic structure was maintained after the impregnation. According to the breakthrough test, the cryogel impregnated with 0.1g of acetylated CNCs exhibits a much higher CO2 capacity with a value of 1.49 mmol/g compared to the CA impregnated ones. The mechanical properties of the cryogels were also evaluated by compression testing, revealing the outstanding reinforcing effect of acetylated CNCs.

  • 1141.
    Wei, Juntao
    et al.
    Key Laboratory of Coal Gasification and Energy Chemical Engineering of Ministry of Education, East China University of Science and Technology, Shanghai, China.
    Gong, Yan
    Key Laboratory of Coal Gasification and Energy Chemical Engineering of Ministry of Education, East China University of Science and Technology, Shanghai, China.
    Ding, Lu
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Yu, Junqin
    Key Laboratory of Coal Gasification and Energy Chemical Engineering of Ministry of Education, East China University of Science and Technology, Shanghai, China.
    Yu, Guangsuo
    Key Laboratory of Coal Gasification and Energy Chemical Engineering of Ministry of Education, East China University of Science and Technology, Shanghai, China. State Key Laboratory of High-efficiency Coal Utilization and Green Chemical Engineering, College of Chemistry and Chemical Engineering, Ningxia University, Yinchuan, China.
    Influence of Biomass Ash Additive on Reactivity Characteristics and Structure Evolution of Coal Char–CO2 Gasification2018Inngår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 32, nr 10, s. 10428-10436Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this study, the influence of biomass ash (rice straw ash, RSA) additive on char gasification reactivity of different rank coals (Shenfu bituminous coal and Zunyi anthracite) was investigated using thermogravimetric analysis. Moreover, the structure characteristics (i.e., the chemical forms and concentrations of AAEM species and the order degree of carbon structure) of gasified semichars were quantitatively studied to evaluate the effect of RSA additive on coal char structure evolution during gasification. Specific reactivity index was proposed as a quantitative index and showed that RSA additive facilitated coal char gasification, especially at lower gasification temperature and for high-rank coal char. In addition, the results from the active AAEM concentrations and the Raman band area ratios of gasified semichars indicate that the RSA additive was conducive to the increase of active AAEM concentrations in coal char and the decrease of the degree of graphitization of coal char carbon structure during gasification, which were more significant at lower temperature and for high-rank coal char. It could be concluded from these results that the function mechanism of the RSA additive on coal char gasification reactivity had a close relationship with char structure evolution during gasification. Kinetics analysis using isoconversional method demonstrated that the gasification activation energy of Shenfu and Zunyi coal char with RSA additive were respectively lower than those of the corresponding coal chars by 8.33 and 22.32 kJ mol-1, indicating that the RSA additive was favorable for activation energy reduction of coal char gasification, especially for high-rank coal char. This work verified the possibility of promoting coal gasification using biomass ash as a natural catalyst and revealed the function mechanism of biomass ash additive on coal char gasification.

  • 1142.
    Wei, Juntao
    et al.
    Key Laboratory of Coal Gasification and Energy Chemical Engineering of Ministry of Education, East China University of Science and Technology, Shanghai.
    Gong, Yan
    Key Laboratory of Coal Gasification and Energy Chemical Engineering of Ministry of Education, East China University of Science and Technology, Shanghai.
    Guo, Qinghua
    Key Laboratory of Coal Gasification and Energy Chemical Engineering of Ministry of Education, East China University of Science and Technology, Shanghai.
    Chen, Xueli
    Key Laboratory of Coal Gasification and Energy Chemical Engineering of Ministry of Education, East China University of Science and Technology, Shanghai.
    Ding, Lu
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Yu, Guangsuo
    Key Laboratory of Coal Gasification and Energy Chemical Engineering of Ministry of Education, East China University of Science and Technology, Shanghai.
    A mechanism investigation of synergy behaviour variations during blended char co-gasification of biomass and different rank coals2018Inngår i: Renewable energy, ISSN 0960-1481, E-ISSN 1879-0682, Vol. 131, s. 597-605Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Co-gasification reactivity of rice straw and bituminous coal/anthracite blended chars under CO2 atmosphere was evaluated using thermogravimetric analysis, and the influences of coal type and gasification temperature on synergy behaviour variations on co-gasification reactivity as carbon conversions increased were quantitatively studied. Furthermore, the chemical forms and concentrations of AAEM species at different co-gasification conversions were quantitatively analyzed for revealing co-gasification synergy mechanism. The results demonstrate that as conversions increased, synergy behaviour on co-gasification reactivity of rice straw-bituminous coal blends was shown as the weakened inhibition effect firstly and then the enhanced synergistic effect. Moreover, the inhibition effect on co-gasification reactivity of rice straw-bituminous coal blends was sustained up to higher conversion with the increment of gasification temperature. Differing from rice straw-bituminous coal blends, synergistic effect on co-gasification reactivity of rice straw-anthracite blends was obviously enhanced at early stage of co-gasification and started to slowly weaken after reaching the most significant synergistic effect at middle stage of co-gasification. Additionally, it was revealed that synergy behaviour variations on co-gasification reactivity of rice straw-bituminous coal blends were mainly attributed to the combination effects of active K and Ca transformation during co-gasification, while those of rice straw-anthracite blends indicated a good correlation with active K transformation during co-gasification.

  • 1143.
    Weiland, Fredrik
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Pressurized entrained flow gasification of pulverized biomass: Experimental characterization of process performance2015Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The anthropogenic emissions of greenhouse gases (e.g. CO2), mostly connected to the use of fossil fuels, to the atmosphere have increased during the last century and there is significant evidence that this is the main reason for the recent global temperature rise. Urgent action is necessary to steer the energy systems on to a safer path by reducing the CO2 emissions to mitigate further climate changes. Sustainable production of CO2-neutral bio-based transportation fuels is one alternative to reduce the dependence on fossil fuels and to reduce the net CO2 emissions from road traffic.One of the goals in the national energy strategy of Sweden is that the vehicle fleet should be independent of fossil fuels by 2030. Pressurized, O2 blown, entrained flow gasification of forest residues followed by methanol production is one of the suggested routes for the production of synthetic motor fuels that could help reach this goal. One of the benefits with entrained flow gasification is that a syngas with high quality is generated. The high syngas quality is necessary for the subsequent synthesis to biofuels. However, there are still a number of hurdles to overcome before large-scale commercial application of this technology can be done. In this context, a pressurized O2 blown entrained flow biomass gasifier (PEBG) was built to demonstrate the ability to gasify pulverized biomass without extensive pretreatment other than drying and milling. This thesis focuses on the understanding of the dominating mechanisms during entrained flow gasification of solid biomass. Athorough process characterization was performed to study the effect of the most important process parameters, e.g. the O2 stoichiometric ratio (λ), the process pressure, the fuel load and the fuel particle size distribution. In addition to this, experiments were performed with different types of wood residues. The wood residues were pretreated differently in order to study the effect of the fuel pretreatment (e.g. torrefaction) and/or the fuel composition. The process performance was measured in terms of syngas yield, the syngas composition and the gasification process efficiency. In some cases, special attention was placed on the syngas particulates that were examined with respect to particle composition and morphology in order to increase the understanding of the particle formation process.The results in this work showed that the maximum cold gas efficiencies CGEpower and CGEfuel from gasification of stem wood were 76 % (at λ=0.30) and 71 % (at λ=0.35), respectively. This work also showed the importance of minimizing the heat losses from the gasifier in order to achieve as high CGE as possible. It was therefore concluded that a well-insulated refractory lined gasifier is the preferred alternative regarding reactor design to maximize the CGE. To generate a high quality syngas, the gasifier should preferably be operated close to the maximum design load, with a λ aiming for process temperatures above 1400 °C in order to keep the levels of CH4 andother unwanted syngas species low. At this temperature, the experimental results suggest that a plug-flow residence time of 3 sec was sufficient to reduce the syngas concentrations of CH4 and C6H6 below 1 mol-% and 100 ppm (on a dry and N2 free basis), respectively. Finally, the syngas particulates from gasification of stem wood were composed mainly of soot with concentrically stacked graphitic layers. It was concluded that the soot yield and the soot particle size could be reduced if the gasifier was operated at high λ. Gasification of bark-based fuels with higher amount of ash indicated lower concentration of particulates in the syngas. Especially K and Zn seemed to affect the syngas particle morphology.

  • 1144.
    Weiland, Fredrik
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Hedman, Henry
    Energy Technology Centre, Piteå.
    Marklund, Magnus
    Energy Technology Centre, Piteå.
    Wiinikka, Henrik
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Öhrman, Olov
    Gebart, Rikard
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Pressurized oxygen blown entrained-flow gasification of wood powder2013Inngår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 27, nr 2, s. 932-941Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In the present study, an oxygen blown pilot scale pressurized entrained-flow biomass gasification plant (PEBG, 1 MWth) was designed, constructed, and operated. This Article provides a detailed description of the pilot plant and results from gasification experiments with stem wood biomass made from pine and spruce. The focus was to evaluate the performance of the gasifier with respect to syngas quality and mass and energy balance. The gasifier was operated at an elevated pressure of 2 bar(a) and at an oxygen equivalence ratio (λ) between 0.43 and 0.50. The resulting process temperatures in the hot part of the gasifier were in the range of 1100-1300 °C during the experiments. As expected, a higher λ results in a higher process temperature. The syngas concentrations (dry and N 2 free) during the experiments were 25-28 mol % for H2, 47-49 mol % for CO, 20-24 mol % for CO2, and 1-2 mol % for CH 4. The dry syngas N2 content was varied between 18 and 25 mol % depending on the operating conditions of the gasifier. The syngas H 2/CO ratio was 0.54-0.57. The gasifier cold gas efficiency (CGE) was approximately 70% for the experimental campaigns performed in this study. The synthesis gas produced by the PEBG has potential for further upgrading to renewable products, for example, chemicals or biofuels, because the performance of the gasifier is close to that of other relevant gasifiers

  • 1145.
    Weiland, Fredrik
    et al.
    SP Energy Technological Center.
    Hedman, Henry
    SP Energy Technological Center.
    Wiinikka, Henrik
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap. SP Energy Technology Center.
    Marklund, Magnus
    SP Energy Technological Center.
    Pressurized Entrained Flow Gasification of Pulverized Biomass: Experiences from Pilot Scale Operation2016Inngår i: Chemical Engineering Transactions, ISSN 1974-9791, E-ISSN 2283-9216, Vol. 50, s. 325-330Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    One of the goals in the national energy strategy of Sweden is that the vehicle fleet should be independent of fossil fuels by 2030. To reach that goal and to domestically secure for supply of alternative fuels, one of the suggested routes is methanol production from forest residues via pressurized and oxygen blown entrained flow gasification. In this context, ongoing industrial research in a 1 MWth gasification pilot plant is carried out at SP Energy Technology Center (SP ETC) in Pitea, Sweden. The plant is operated with pulverized or liquid fuels at process pressures up to 10 bar and this work summarizes the experiences from over 600 hours of operation with forest based biomass fuels. This paper covers results from thorough process characterization as well as results from extractive samplings of both permanent gases and particulate matter (soot) from inside the hot gasifier. Furthermore, the challenges with pressurized entrained flow gasification of pulverized biomass are discussed. During the characterization work, four of the most important process parameters (i.e. oxygen stoichiometric ratio (lambda), fuel load, process pressure and fuel particle size distribution) were varied with the purpose of studying the effect on the process performance and the resulting syngas quality. The experimental results showed that the maximum cold gas efficiency (CGE) based on all combustible species in the syngas was 75% (at lambda=0.30), whereas the corresponding value based only on CO and H-2 (with respect to further MeOH synthesis from the syngas) was 70% (at lambda=0.35). As expected, the pilot experiments showed that both the soot yield and soot particle size was reduced by increasing lambda. One of the additional conclusions from this work was that; minimizing heat losses from the gasifier is of utmost importance to optimize the process performance regarding energy efficiency (i.e. CGE). Therefore, a well-insulated refractory lined gasifier is the primary alternative in regards to reactor design to maximize the CGE. Future development of the PEBG process should focus on identifying suitable hot-phase refractory, that exhibit long life-time and can sustain the alkali-rich biomass ash under gasification conditions. In addition to this, the remaining issue around how to improve the slag flow from the reactor, by additives or fuel mixing, should be investigated.

  • 1146.
    Weiland, Fredrik
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Nilsson, Patrik T.
    Ergonomics and Aerosol Technology, Lund University.
    Gebart, Rikard
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Wiinikka, Henrik
    Gudmundsson, Anders
    Ergonomics and Aerosol Technology, Lund University.
    Sanati, Mehri
    Ergonomics and Aerosol Technology, Lund University.
    Online Characterization of Syngas Particulates Using Aerosol Mass Spectrometry in Entrained-Flow Biomass Gasification2014Inngår i: Aerosol Science and Technology, ISSN 0278-6826, E-ISSN 1521-7388, Vol. 48, nr 11, s. 1145-1155Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Entrained flow gasification is a promising technique where biomass is converted to a synthesis gas (syngas) under fuel rich conditions. In contrast to combustion, where the fuel is converted to heat, CO2 and H2O, the syngas from gasification is rich in energetic gases such as CO and H2. These compounds (CO and H2) represent the building blocks for further catalytic synthesis to chemicals or biofuels. Impurities in the syngas, such as particulates, need to be reduced to different levels depending on the syngas application. The objective of this work was to evaluate the amount of particulates; the particle size distribution and the particle composition from entrained flow gasification of pine stem wood at different operating conditions of the gasifier. For this purpose online time resolved measurements were performed with a Soot Particle Aerosol Mass Spectrometer (SP-AMS) and a Scanning Mobility Particle Sizer (SMPS). The main advantage of SP-AMS compared to other techniques is that the particle composition (soot, PAH, organics and ash forming elements) can be obtained with high time resolution and thus studied as a direct effect of the gasifier operating conditions. The results suggest that syngas particulates were essentially composed of soot at these tested process temperatures in the reactor (1200–1400 °C). Furthermore, the AMS analysis showed a clear correlation between the amounts of polycyclic aromatic hydrocarbons (PAH) and soot in the raw syngas. Minimization of soot and PAH yields from entrained flow gasification of wood proved to be possible by further increasing the O2 addition.

  • 1147.
    Weiland, Fredrik
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Nordwaeger, Martin
    Umeå University. Department of Applied Physics and Electronics.
    Olofsson, Ingemar
    Umeå University. Department of Applied Physics and Electronics.
    Nordin, Anders
    Umeå University. Department of Applied Physics and Electronics.
    Wiinikka, Henrik
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Entrained flow gasification of torrefied wood residues2014Inngår i: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 125, s. 51-58Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this work, four different fuels were gasified in a pressurized entrained flow pilot plant gasifier at approximately 270 kWth. The different fuels were; two torrefied wood residues, one raw wood residue and one torrefied stem wood. The system pressure and oxygen equivalence ratio (λ) were held constant for all four gasification experiments. It was found that the torrefaction pretreatment significantly reduced the milling energy consumption for fuel size reduction, which in turn contributed to increased gasification plant efficiency. Furthermore, the results indicate that the carbon conversion efficiency may be enhanced by an intermediate torrefaction pretreatment, whereas both less severe torrefaction and more severe torrefaction resulted in reduced carbon conversions. The results also indicate that the CH4 yield was significantly reduced for the most severely torrefied fuel.

  • 1148.
    Weiland, Fredrik
    et al.
    SP Energy Technology Center AB.
    Sweeney, Daniel J.
    SP Energy Technology Center AB.
    Wiinikka, Henrik
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Extractive Sampling of Gas and Particulates from the Reactor Core of an Entrained Flow Biomass Gasifier2016Inngår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 30, nr 8, s. 6405-6412Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    With the purpose of demonstrating a process for pressurized entrained flow gasification for pulverized biomass, the aim with this work was to characterize the conditions inside the gasifier. To gain a broader understanding, it was important to extract both gases. and particulate matter from the hot reaction zone. The objectives were, therefore, to (1) develop a sampling system capable of extracting both gas and particulates from the gasifier, (2) study the production of particulate matter as well as its composition and size distribution as a function of different operating conditions, and (3) extract time-resolved data for the syngas species (CO, CO2, and CH4) in order to study the compositional variance. The results indicated that the syngas heating value was lower at the sampling position in the gasifier compared to the heating value measured downstream of the quench cooler. The difference was most probably an effect of ongoing gasification of carboneous Solids downstream of the sampling position in the gasifier. Furthermore, it was concluded that the fuel feedrate was fluctuating, most likely because of heterogeneity in the fuel powder and/or the challenges, in the fuel feeding system itself. With regards to particulate matter, in the syngas, it was shown to mostly consist of soot. The soot yield was significantly reduced by increasing lambda. The reactor cote sampling system proved superior to the traditional sampling system downstream of the quench with regard to measuring soot yield at different operating conditions of the gasifier. Finally, it was concluded that the submicron fly ash particles from oxygen blown biomass gasification contain high propotions of refractory elements (e.g., Ca, Mg, and Si) in addition to the more volatile elements (e.g., K, Na, S, and Cl). This is probably due to extremely high temperature in the flame and substoichiometric condition in the gasifier, which may promote vaporization of refractory elements during, char gasification

  • 1149.
    Weiland, Fredrik
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Wiinikka, Henrik
    Hedman, Henry
    Energy Technology Centre, Piteå, SP Energy Technology Center AB.
    Wennebro, Jonas
    SP Energy Technology Center AB.
    Pettersson, Esbjörn
    LTU/ETC, Energy Technology Centre, Piteå, SP Energy Technology Center AB.
    Gebart, Rikard
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Influence of process parameters on the performance of an oxygen blown entrained flow biomass gasifier2015Inngår i: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 153, s. 510-519Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Pressurized, O2 blown, entrained flow gasification of pulverized forest residues followed by methanol production is an interesting option for synthetic fuels that has been particularly investigated in the Nordic countries. In order to optimize gasification plant efficiency, it is important to understand the influence of different operating conditions. In this work, a pressurized O2 blown and entrained flow biomass gasification pilot plant was used to study the effect of four important process variables; (i) the O2 stoichiometric ratio (λ), (ii) the load of the gasifier, (iii) the gasifier pressure, and (iv) the fuel particle size. Commercially available stem wood fuels were used and the process was characterized with respect to the resulting process temperature, the syngas yield, the fuel conversion and the gasification process efficiency. It was found that CH4 constituted a significant fraction of the syngas heating value at process temperatures below 1400 °C. If the syngas is intended for catalytic upgrading to a synthetic motor fuel where CO and H2 are the only important syngas species, the process should be optimized aiming for a process temperature slightly above 1400 °C in order to reduce the energetic losses to CH4 and C6H6. This resulted in a cold gas efficiency (based only on CO and H2) of 70%. The H2/CO ratio was experimentally determined within the range 0.45–0.61. Thus, the syngas requires shifting in order to increase the syngas composition of H2 prior to fuel synthesis.

  • 1150.
    Westerlund, Lars
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Absorptionsteknik: förstudie1988Rapport (Annet vitenskapelig)
20212223242526 1101 - 1150 of 1281
RefereraExporteraLink til resultatlisten
Permanent link
Referera
Referensformat
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf