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  • 1251.
    Zetterholm, Jonas
    et al.
    Department of Process Integration, Swerea MEFOS AB.
    Ji, Xiaoyan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Sundelin, Bo
    SSAB EMEA Oxelösund.
    Martin, Peter M.
    Siemens VAI Metals Technologies.
    Wang, Chuan
    Swerea MEFOS AB, Center for Process Integration in Steelmaking, Swerea MEFOS, Luleå.
    Model Development of a Blast Furnace Stove2015In: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 75, p. 1758-1765Article in journal (Refereed)
    Abstract [en]

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

  • 1252.
    Zetterholm, Jonas
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Ji, Xiaoyan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Sundelin, Bo
    SSAB EMEA Oxelösund , SSAB Special Steels Oxelösund.
    Martin, P.M.
    Siemens VAI Metals Technologies, United States.
    Wang, C.
    Department of Process Integration, Swerea MEFOS AB.
    Dynamic modelling for the hot blast stove2017In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 185, no 2, p. 2142-2150Article in journal (Refereed)
    Abstract [en]

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

  • 1253.
    Zetterholm, Jonas
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Mossberg, Johanna
    RISE Research Institutes of Sweden, Bioeconomy.
    Joakim, Lundgren
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Wetterlund, Elisabeth
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Evaluating investments in integrated biofuel production - factoring in uncertainty through real options analysis2019In: PROCEEDINGS OF ECOS 2019 / [ed] Wojciech Stanek, Paweł Gładysz, Sebastian Werle, Wojciech Adamczyk, 2019, p. 1921-1932Conference paper (Refereed)
    Abstract [en]

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

  • 1254.
    Zetterholm, Jonas
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Pettersson, Karin
    RISE Research Institutes of Sweden, Eklandagatan 86, SE-412 61 Gothenburg.
    Leduc, Sylvain
    International Institute for Applied Systems Analysis (IIASA), Schlossplatz 1, A-2361 Laxenburg.
    Lundgren, Joakim
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science. International Institute for Applied Systems Analysis (IIASA), Schlossplatz 1, A-2361 Laxenburg.
    Wetterlund, Elisabeth
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science. International Institute for Applied Systems Analysis (IIASA), Schlossplatz 1, A-2361 Laxenburg.
    Resource efficiency or economy of scale: Biorefinery supply chain configurations for co-gasification of black liquor and pyrolysis liquids2018In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 230, p. 912-924Article in journal (Refereed)
    Abstract [en]

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

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

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

  • 1255.
    Zetterholm, Jonas
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Wetterlund, Elisabeth
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Pettersson, Karin
    SP/Energi och bioekonomi/Energi- och miljösystemanalys.
    Lundgren, Joakim
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Evaluation of co-gasification of black liquor and pyrolysis liquids from a national systems perspective2016In: Meeting Sweden's current and future energy challenges, Luleå: Luleå tekniska universitet, 2016, Luleå: Luleå tekniska universitet, 2016Conference paper (Other academic)
  • 1256.
    Zetterholm, Jonas
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Wetterlund, Elisabeth
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science. International Institute for Applied Systems Analysis (IIASA), Laxenburg, Austria.
    Pettersson, Karin
    RISE Research Institutes of Sweden, Eklandagatan 86, Göteborg, Sweden.
    Lundgren, Joakim
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science. International Institute for Applied Systems Analysis (IIASA), Laxenburg, Austria.
    Evaluation of value chain configurations for fast pyrolysis of lignocellulosic biomass: Integration, feedstock, and product choice2018In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 144, p. 564-575Article in journal (Refereed)
    Abstract [en]

    Fast pyrolysis of lignocellulosic biomass constitutes a promising technology to reduce dependence on fossil fuels. The product, pyrolysis liquids, can either substitute heavy fuel oil directly, or be upgraded via e.g. hydroprocessing to diesel and petrol. This study presents a systematic evaluation of production costs and CO2 mitigation potentials of different fast pyrolysis value chain configurations. The evaluation considers types of localisations, emissions from electricity and hydrogen production, biomass feedstocks, and final products. The resulting production costs were found to be in the range of 36–60 EUR/MWh for crude pyrolysis liquids, and 61–90 EUR/MWh upgraded to diesel and petrol. Industrial integration was found to be favoured. The CO2 mitigation potential for the pyrolysis liquids was in the range of 187–282 t-CO2/GWh biomass. High variations were found when upgraded to diesel and petrol –best-case scenario resulted in a mitigation of 347 t-CO2/GWh biomass, while worst-case scenarios resulted in net CO2 emissions. Favourable policy support, continued technology development, and/or increased fossil fuel prices are required for the technology to be adapted on an industrial scale. It was concluded that integration with existing industrial infrastructure can contribute to cost reductions and thus help enable the transformation of traditional forest industry into biorefineries.

  • 1257.
    Zhang, Guanru
    et al.
    School of Earth Sciences, Zhejiang University, Hangzhou .
    Lu, Peng
    Department of Geological Sciences, Indiana University, Bloomington, IN .
    Ji, Xiaoyan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Zhu, Chen
    School of Earth Sciences, Zhejiang University, Hangzhou .
    CO2 Plume Migration and Fate at Sleipner, Norway: Calibration of Numerical Models, Uncertainty Analysis, and Reactive Transport Modelling of CO2 Trapping to 10,000 Years2017In: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 114, p. 2880-2895Article in journal (Refereed)
    Abstract [en]

    The Sleipner Project in Norway is the world's first industrial-scale geological carbon dioxide storage project. Time-lapse seismic monitoring data have been collected, tracing CO2 plume development from 1996 to 2010. Therefore, the Sleipner Project provides a somewhat unique opportunity to simulate the dynamics of CO2 in a real geological system. The purpose of this study is to simulate CO2 plume migration dynamics and assess the impact of uncertain factors on short and long term migration and fate of CO2 for the uppermost layer (Layer 9) of the Utsira Sand.

    First, we applied a multi-phase compositional simulator to the Sleipner Benchmark model for Layer 9 and calibrated our model against the time-lapsed seismic monitoring data at the site from 1999 to 2008. By adjusting lateral permeability anisotropy, CH4 in the CO2 stream, and reservoir temperature, approximate match with the observed plume was achieved. Model-predicted gas saturation, thickness of the CO2 accumulation, and CO2 solubility in brine (none of them used as calibration metrics) were all comparable with interpretations of the seismic data in the literature.

    Second, hundreds of simulations of parameter sensitivity (pressure, temperature, feeders, spill rates, relative permeability curves, and CH4 content) were conducted for the plume migration, based on the calibrated model. The results showed that simulated plume extents are sensitive to permeability anisotropy, temperature, and CH4 content, but not sensitive to the other parameters. However, adjusting a single parameter within the reported range of values in the literature would not reproduce the north-south trending CO2 plume; it took a combination of permeability, CH4, and temperature adjustments to match simulated CO2 plume with seismic monitoring data. Although there is a range of uncertain parameters, the predicted fate of CO2 fell within a narrow band, ∼ 93±2% structural trapping and ∼ 7±2% solubility trapping. The calibrated model is not unique. Many combinations of permeability anisotropy, temperature, and CH4 would produce similar matches. Other possibilities that would have improved the development of an N–S elongated CO2 plume, such as a slight tilting of the surface of Utsira top to the south, were not experimented in this study, but are worthy of exploration for future studies.

    Finally, we used coupled reactive mass transport model to investigate the effects of rate laws and regional groundwater flow on long-term CO2 fate in Layer 9. The mineral composition and brine chemistry for the Utsira sand were adopted from the literature, and we modelled 100 year injection and continued water-rock interaction to 10,000 years. The results indicated that: (1) The predicted fraction of CO2 mineral trapping when using the linear rate law for feldspar dissolution is twice as much as when using the non-linear rate law. (2) Mineral trapping is more significant when regional groundwater flow is taken into consideration. Under the influence of regional groundwater flow, the replenishment of fresh brine from upstream continuously dissolves CO2 at the tail of CO2 plume, generating a larger acidified area where mineral trapping takes place. In a Sleipner like aquifer, the upstream replenishment of groundwater results in ∼ 22% mineral trapping at year 10,000, compared to the ∼ 4% when the effects of regional groundwater are ignored.

  • 1258.
    Zhang, Yingying
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Thermodynamic Analysis and Screening ILs/DESs-based Absorbents for CO2 Separation2016Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    CO2 separation plays an important role in both biofuel production, and CO2 capture and storage (CCS) implementation to deal with global warming. The available CO2 separation technologies are either energy-intensive or require large-scale operations, and it is crucial to develop novel CO2 separation technology in order to optimize the energy uses and the amounts of CO2-absorbents/adsorbents.Recently, ionic liquids (ILs) have been proposed as potential liquid absorbents for CO2 separation with remarkable properties. A lot of ILs have been synthesized for this purpose. The CO2 absorption capacity/selectivity and the energy use have been considered in screening ILs, while the amounts of ILs needed have seldom been considered in the screening process. Meanwhile, the high-cost, toxicity and poor biodegradability of the conventional ILs limit their applications in large-scale. Deep eutectic solvents (DESs) have emerged as a new type of ILs, and in particular, those based on choline salts (i.e. choline-based DESs) show additional advantages in cost, environmental impact and synthesis. Choline-based DESs have been synthesized and the research work related to CO2 separation with this series of DESs and their aqueous solutions has been carried out. However, it is still unclear which absorbent can achieve a better performance for CO2 separation.The choice of absorbents for CO2 separation depends on gas streams, and the performances of absorbents for CO2 separation relate to the energy uses and the amounts of absorbents needed. In this thesis work, four gas streams (i.e. flue gas and lime kiln gas from the combustion of fossil-fuels, biogas from the anaerobic digestion of biomass as well as bio-syngas from the gasification of biomass) with different temperature, pressure, CO2 concentration and gaseous components were considered, and CO2 separation from four gas streams was analyzed thermodynamically based on Gibbs free energy change. The analysis shows that biogas is the CO2 stream with the lowest theoretical energy penalty. Therefore, biogas was chosen as a specific CO2 stream for further evaluating the performances of CO2 absorbents.In evaluation, the conventional ILs were first analyzed and screened for CO2 separation from biogas with three options (i.e. option 1: the CO2 dissolution enthalpy and CO2 working capacity, option 2: the energy use, and option 3: the energy use and the amount of IL needed). The investigation shows that the screen of ILs is strongly related to the operational condition and the screening criteria. In the option of “the energy use and the amount of IL needed”, the operational condition was optimized based on the minimum Gibbs free energy change, and the energy use and the amount of IL needed were considered in screening. While in other screening options, the operational conditions were presumed and the amounts of ILs needed were not considered. Therefore, the option of “the energy use and the amount of IL needed” is more reasonable compared to the other two options. The performances of these screened conventional ILs were further compared with those of the commercial CO2 absorbents. It shows that the conventional ILs are promising CO2 absorbents due to lower energy uses or lower amounts of ILs needed combined with the advantage of non-volatility.The research work on choline-based DESs and their aqueous solutions for CO2 separation was surveyed and reviewed. Generally, the properties of choline-based DESs are similar to those of conventional ILs. Considering the additional advantages of low-cost, non-toxicity and biodegradability, choline-based DESs are more promising for CO2 separation. However, due to the limited available research work, further studies need to be carried out from experimental measurements to model developments. The performances of choline-based-DESs for CO2 separation from biogas were analyzed. Based on the option of “the energy use and the amount of absorbent needed”, the choline-based-DESs were screened and then compared with the conventional ILs and the commercial CO2 absorbents. The comparison results show that the choline-based-DESs are more promising for CO2 separation from biogas due to the non-volatility, lower energy uses or lower amounts of absorbents needed. In addition, CO2 separation from other CO2 streams was further investigated. It shows that the physical absorbents are more suitable for the CO2 streams with high CO2 concentration (i.e. biogas, lime kiln gas and bio-syngas), while the chemical CO2 absorbents are more suitable for that with low CO2 concentration and high temperature (i.e. flue gas). Considering the high amounts of physical absorbents, further study needs to be carried out with techno-economic analysis.

  • 1259.
    Zhang, Yingying
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Ji, Xiaoyan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Lu, Xiaohua
    State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing University of Technology.
    Application of choline-based deep eutectic solvents in CO2 capture and separation2014In: Huagong Xuebao/Journal of Chemical Industry and Engineering, ISSN 0438-1157, Vol. 65, no 5, p. 1721-1728Article in journal (Refereed)
    Abstract [en]

    Choline-based deep eutectic solvents (DESs) are a new class of ionic liquids. With similar properties to ionic liquids, choline-based DESs have the advantages of easy synthesis, low price, low toxicity and biodegradability. In this work, the properties of choline-based DESs related to CO2 capture and separation were investigated, such as gas solubility, CO2 absorption-desorption, density, thermal stability, viscosity and surface tension. The influence of the structure of choline-based DESs on their properties were analyzed. The comparison of choline-based DESs with traditional ionic liquid showed that choline-based DESs could be used as absorbents for CO2 capture and separation due to high CO2 solubility and low viscosity. However, more research needs to be done before commercial application, for example, CO2 selectivity compared to other components in gas mixtures, surface tension as well as thermal-stability.

  • 1260.
    Zhang, Yingying
    et al.
    Department of Material and Chemical Engineering, Zhengzhou University of Light Industry, 450002 Zhengzhou, China.
    Ji, Xiaoyan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Lu, Xiaohua
    State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, 210009 Nanjing, China.
    Choline-based deep eutectic solvents for CO2 separation: Review and thermodynamic analysis2018In: Renewable & sustainable energy reviews, ISSN 1364-0321, E-ISSN 1879-0690, Vol. 97, p. 436-455Article in journal (Refereed)
    Abstract [en]

    CO2 separation plays an important role in energy saving and CO2 emission reduction, both of which are necessary to address the issue of global warming. Ionic liquids (ILs) have been proposed to be “green” solvents for CO2 separation. Unfortunately, the high cost, toxicity, and poor biodegradability of these compounds limit their large-scale application. Deep eutectic solvents (DESs) were recently considered a new type of IL with additional advantages in terms of cost, environmental impact, and synthesis. DESs based on choline salts (i.e., choline-based DESs) are promising candidates for CO2 separation. In this work, the microstructures, physicochemical properties, and water effect of choline-based DESs are surveyed and compared with those of conventional ILs. The properties of choline-based DESs are similar to those of conventional ILs, but research on the latter remains limited. Further study on the microstructures, properties, and separation performance of choline-based DESs considering dynamic factors must be carried out through experimental measurements and model development. Thermodynamic analysis based on Gibbs free energy change is conducted to investigate the performances of choline-based-DESs during CO2 separation from biogas. Choline-based-DESs are screened on the basis of energy use and amount of absorbent needed. The performances of the screened choline-based-DESs are further compared with those of conventional ILs screened in our previous work, as well as commercial CO2 absorbents. Comparisons indicate that the screened DES-based absorbents show great application potential due to their nonvolatility, low energy use, or low amount required. The performances of physical choline-based-DES and 30 wt% MEA for CO2 separation from other gas streams (e.g., flue gas, lime kiln gas, and bio-syngas) are discussed. Considering the high amounts of physical absorbents required to enable separation, further study with techno-economic analysis needs to be carried out.

  • 1261.
    Zhang, Yingying
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Ji, Xiaoyan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Lu, Xiaohua
    State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing University of Technology, College of Chemistry and Chemical Engineering, Nanjing University of Technology.
    Choline-Based Deep Eutectic Solvents for Mitigating Carbon Dioxide Emissions2015In: Novel Materials for Carbon Dioxide Mitigation Technology, Elsevier, 2015, p. 87-116Chapter in book (Refereed)
    Abstract [en]

    Global warming is a critical issue facing human beings due to greenhouse gas emissions, especially CO2 emissions. Mitigating CO2 emissions by Carbon capture and storage (CCS) has become a hot topic today. CO2 separation is a crucial step in CCS and is an energy-intensive process. Ionic liquids (ILs) as green solvents have gained tremendous attention for use as liquid absorbents for CO2 separation. However, the high price, toxicity, and poor biodegradability limit the application of ILs. Recently, deep eutectic solvents (DESs) based on choline chloride (ChCl) (i.e., choline-based DESs) were proposed as a new type of ILs but with additional advantages in cost, environmental impact, and synthesis. To promote the application of choline-based DESs in CO2 separation, the research work on the microstructure and physicochemical properties of choline-based DESs as well as the water effect were surveyed and compared with traditional ILs. The potential applications of choline-based DESs in CO2 separation and the challenges were further analyzed. It is shown that choline-based DESs are promising for use as liquid absorbents for CO2 separation, and the performance of ChCl/urea (1:2) is better than that for other choline-based DESs. However, uncertainties and bottlenecks still exist, and further study on the microstructure and properties needs to be carried out from experimental measurements to model developments

  • 1262.
    Zhang, Yingying
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Ji, Xiaoyan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Lu, Xiaohua
    State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing University of Technology.
    Energy consumption analysis for CO2 separation from gas mixtures2014In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 130, no S1, p. 237-243Article in journal (Refereed)
    Abstract [en]

    CO2 separation is an energy intensive process, which plays an important role in both energy saving and CO2 capture and storage (CCS) implementation to deal with global warming. To quantitatively investigate the energy consumption of CO2 separation from different CO2 streams and analyze the effect of temperature, pressure and composition on energy consumption, in this work, the theoretical energy consumption of CO2 separation from flue gas, lime kiln gas, biogas and bio-syngas was calculated. The results show that the energy consumption of CO2 separation from flue gas is the highest and that from biogas is the lowest, and the concentration of CO2 is the most important factor affecting the energy consumption when the CO2 concentration is lower than 0.15 in mole fraction. Furthermore, if the CO2 captured from flue gases in CCS was replaced with that from biogases, i.e. bio-CO2, the energy saving would be equivalent to 7.31 million ton standard coal for China and 28.13 million ton standard coal globally, which corresponds to 0.30 billion US$ that can be saved for China and 1.36 billion US$ saved globally. This observation reveals the importance of trading fossil fuel-based CO2 with bio-CO2.

  • 1263.
    Zhang, Yingying
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Ji, Xiaoyan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Xie, Yujiao
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Lu, Xiaohua
    State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing University of Technology, College of Chemistry and Chemical Engineering, Nanjing University of Technology.
    Screening of conventional ionic liquids for carbon dioxide capture and separation2016In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 162, p. 1160-1170Article in journal (Refereed)
    Abstract [en]

    CO2 capture and storage could efficiently mitigate CO2 emissions, wherein CO2 capture is a crucial energy-intensive process. Ionic liquids (ILs) have been proposed as potential liquid absorbents for CO2 separation. The CO2 absorption capacity and selectivity of ILs have also been investigated extensively. Although ILs have been screened for CO2 separation, only specific ILs have been examined in terms of energy consumption. In this study, 76 conventional ILs were collected and screened in terms of energy consumption to establish potential ILs for CO2 separation. Seventeen ILs were screened according to the CO2 dissolution enthalpy and CO2 working capacity criteria obtained from the Henry’s law constant in the preliminary screening. Seven ILs were then screened from the 17 ILs according to the CO2 working capacity from the measured CO2 solubility in the final screening. The energy consumptions of the seven screened ILs (i.e., [Emim][NTf2], [Bmim][BF4], [Bmim][PF6], [Bmim][NTf2], [Hmim][NTf2], [Bmpy][NTf2], and [Hmpy][NTf2]) were calculated, and the corresponding gas solubility selectivities were discussed. The energy consumptions and properties of the seven screened ILs were compared with those of the commercial CO2 absorbents of 30 wt% MEA, 30 wt% MDEA, and dimethyl ethers of polyethylene glycol (Selexol™ or Coastal AGR®). The results showed that the energy consumptions of the seven screened ILs were lower than those of the commercial CO2 absorbents. [Hmpy][NTf2] showed the lowest energy consumption among the seven screened ILs under the operating conditions set in this study.

  • 1264.
    Zhang, Yingying
    et al.
    Department of Material and Chemical Engineering, Zhengzhou University of Light Industry.
    Ji, Xiaoyan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Xie, Yujiao
    School of Chemical Engineering, Shandong University of Technology.
    Lu, Xiaohua
    Key Laboratory of Material and Chemical Engineering, Nanjing Tech University, Nanjing .
    Thermodynamic analysis of CO2 separation from biogas with conventional ionic liquids2018In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 217, p. 75-87Article in journal (Refereed)
    Abstract [en]

    CO2 separation plays an important role in energy saving and CO2 emission reduction to address global warming. Ionic liquids (ILs) have been proposed as potential absorbents for CO2 separation, and a large amount of ILs have been synthesized to achieve this purpose. To screen ILs for CO2 separation, CO2 absorption capacity/selectivity and energy use have been considered, whereas the required amount of IL has been seldom involved. In this work, CO2 separation from biogas with 30 conventional ILs was analyzed theoretically on the basis of the Gibbs free energy change combining the amount of IL needed and the energy use. The desorption temperature was estimated from the absorption pressure, and then the amount of IL needed and the energy use were calculated. Thermodynamic analysis shows that the absorption pressure and the desorption temperature need to be changed to achieve optimal separation. Several ILs were screened with certain criteria, namely, the amount of IL needed and energy use. The performance of the screened ILs was compared with that of commercial CO2 absorbents (30 wt% MEA, 30 wt% MDEA, DEPG, and water). The comparison with DEPG and water shows that the screened physical ILs are promising for IL-based technologies because of their advantages of negligible vaporization enthalpy, low amount of absorbent needed, or low energy use. A comparison with 30 wt% MEA and 30 wt% MDEA indicates that chemical IL has negligible vaporization enthalpy and low energy use. These findings show that the screened ILs are promising for CO2 separation from biogas.

  • 1265.
    Zhang, Yingying
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Lu, Xiaohua
    State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing University of Technology.
    Feng, Xin
    State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing University of Technology.
    Shi, Yijun
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Ji, Xiaoyan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Properties and applications of choline-based deep eutectic solvents2013In: Huaxue jinzhan, ISSN 1005-281X, Vol. 25, no 6, p. 881-892Article in journal (Refereed)
    Abstract [en]

    Choline-based deep eutectic solvents (DESs) are considered as a new class of ionic liquids. Comparing to traditional ionic liquids, choline-based DESs are low-toxic, biodegradable, and the price is generally low, which make them more and more attractive in green chemistry and industrial chemistry. In the current work, the properties of choline-based DESs, such as freezing point, melting point, solubility, viscosity, surface tension and conductivity, were collected and summarized. The dependences of these properties with different factors, such as temperature, mole ratios and water content, and the models which can be used to predict the properties were studied and discussed. The applications of choline-based DESs in the area of lubrication, functional material preparation, electrochemistry, organic synthesis and catalytic conversion of biomass were introduced. Finally, the problems and difficulties in research and applications were illustrated and then prospective was provided.

  • 1266.
    Zhang, Yingying
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Xie, Yujiao
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Zhu, Yudan
    State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing University of Technology.
    Lu, Xiaohua
    State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing University of Technology, College of Chemistry and Chemical Engineering, Nanjing University of Technology.
    Ji, Xiaoyan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Energy Consumption Analysis for CO2 Separation from Gas Mixtures with Liquid Absorbents2014In: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 61, p. 2695-2698Article in journal (Refereed)
    Abstract [en]

    CO2 separation is an energy intensive process, and it plays an important role in both energy saving and CO2 capture and storage (CCS) to deal with global-warming. CO2 can be from different sources in a wide temperature, pressure and concentrations range. Meanwhile, new liquid absorbents are under-development to cost-effectively separate CO2 from gas mixtures. All this makes it crucial to analyze the energy consumption for CO2 separation from different streams and with different absorbents. In this work, the theoretical energy consumption of CO2 separation from flue gas (CO2/N2), lime kiln gas (CO2/N2), biogas (CO2/CH4) and bio-syngas (CO2/H2/CO) was calculated. The results show that the energy consumption of CO2 separation from flue gas is the highest and that from biogas is the lowest. If the CO2 captured from flue gases was substituted by that from biogases, the energy saving would be equivalent to 28.13 million ton standard coal globally. The energy consumption of CO2 separation from biogas using traditional absorbent of 30%MEA and new developed ionic liquids (ILs) was further studied, in which 1-ethyl-3-methy- limidazolium bis[(trifluoromethyl)sulfonyl]imide ([Emim][NTf2]), 1-butyl-3-methylimida- zolium tetrafluoroborate ([Bmim][BF4]), 1-hexyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl] imide ([Hmim][Tf2N]) and 1-butyl-1-methylpyrrolidinium bis[(trifluoromethyl)sulfonyl]imide ([Bmpy][Tf2N]) were screened from 75 ILs. The energy consumptions of CO2 separation using ILs are lower than those of 30%MEA and that of [Bmim][BF4] is the lowest in the four screened ILs. With a very low vapor pressure and high CO2 solubility, it's promising to use ILs as absorbents for CO2 separation.

  • 1267.
    Zhang, Yumeng
    et al.
    College of Chemical Engineering, State Key Laboratory of Materials-oriented Chemical Engineering, Nanjing Tech University, Nanjing, P.R. China.
    Zhu, Yudan
    College of Chemical Engineering, State Key Laboratory of Materials-oriented Chemical Engineering, Nanjing Tech University, Nanjing, P.R. China.
    Wang, Anran
    College of Chemical Engineering, State Key Laboratory of Materials-oriented Chemical Engineering, Nanjing Tech University, Nanjing, P.R. China.
    Gao, Qingwei
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science. College of Chemical Engineering, State Key Laboratory of Materials-oriented Chemical Engineering, Nanjing Tech University, Nanjing, P.R. China.
    Qin, Yao
    College of Chemical Engineering, State Key Laboratory of Materials-oriented Chemical Engineering, Nanjing Tech University, Nanjing, P.R. China.
    Chen, Yaojia
    College of Chemical Engineering, State Key Laboratory of Materials-oriented Chemical Engineering, Nanjing Tech University, Nanjing, P.R. China.
    Lu, Xiaohua
    College of Chemical Engineering, State Key Laboratory of Materials-oriented Chemical Engineering, Nanjing Tech University, Nanjing, P.R. China.
    Progress in molecular-simulation-based research on the effects of interface-induced fluid microstructures on flow resistance2019In: Chinese Journal of Chemical Engineering, ISSN 1004-9541, E-ISSN 2210-321X, Vol. 27, no 6, p. 1403-1415Article in journal (Refereed)
    Abstract [en]

    In modern chemical engineering processes, solid interface involvement is the most important component of process intensification techniques, such as nanoporous membrane separation and heterogeneous catalysis. The fundamental mechanism underlying interfacial transport remains incompletely understood given the complexity of heterogeneous interfacial molecular interactions and the high nonideality of the fluid involved. Thus, understanding the effects of interface-induced fluid microstructures on flow resistance is the first step in further understanding interfacial transport. Molecular simulation has become an indispensable method for the investigation of fluid microstructure and flow resistance. Here, we reviewed the recent research progress of our group and the latest relevant works to elucidate the contribution of interface-induced fluid microstructures to flow resistance. We specifically focused on water, ionic aqueous solutions, and alcohol–water mixtures given the ubiquity of these fluid systems in modern chemical engineering processes. We discussed the effects of the interface-induced hydrogen bond networks of water molecules, the ionic hydration of ionic aqueous solutions, and the spatial distributions of alcohol and alcohol–water mixtures on flow resistance on the basis of the distinctive characteristics of different fluid systems.

  • 1268.
    Zheng, Ruimin
    et al.
    University of Hongkong.
    Bollen, Math
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Harmonic resonances associated with wind farms2010Report (Other academic)
  • 1269.
    Zheng, Ruimin
    et al.
    Department of Electrical and Electronic Engineering, University of Hong Kong.
    Bollen, Math
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Zhong, Jin
    STRI AB.
    Harmonic resonances due to a grid-connected wind farm2010In: 14th International Conference on Harmonics and Quality of Power (ICHQP), Piscataway, NJ: IEEE Communications Society, 2010, p. 1-7Conference paper (Refereed)
    Abstract [en]

    This paper studies the impact of a grid-connected wind farm on the harmonic resonances. The basic theory on the harmonic resonances is introduced as well as its consequences. The models of wind farm for resonance analysis are presented for both calculations and simulations. The resonance orders and amplifications of voltage distortion with different capacity of capacitor banks are studied under different operation modes. Several case studies with a 200 MW wind farm have been carried out to illustrate the methods for harmonic resonance analysis. 

  • 1270.
    Zhong, Jin
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Bollen, Math
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Wei, Ming
    The University of HongKong.
    Rönnberg, Sarah
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Towards a 100% Renewable Energy Power Generation in Sweden2016In: Meeting Sweden's current and future energy challenges, Luleå: Luleå tekniska universitet, 2016, Luleå: Luleå tekniska universitet, 2016Conference paper (Other academic)
  • 1271.
    Zhu, Chen
    et al.
    Department of Geological Sciences, Indiana University, Indiana University, Department of Geological Sciences, Bloomington.
    Zhang, Guanru
    Indiana University, Department of Geological Sciences, Bloomington.
    Lu, Peng
    Indiana University, Department of Geological Sciences, Bloomington.
    Meng, Lifeng
    Department of Earth Sciences, Zhejiang University, Hangzhou.
    Ji, Xiaoyan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Benchmark modeling of the Sleipner CO2 plume: Calibration to seismic data for the uppermost layer and model sensitivity analysis2015In: International Journal of Greenhouse Gas Control, ISSN 1750-5836, E-ISSN 1878-0148, Vol. 43, p. 233-246Article in journal (Refereed)
    Abstract [en]

    An important question for the Carbon Capture, Storage, and Utility program is “can we adequately predict the CO2 plume migration?” The Sleipner project in the Norwegian North Sea provides more time-lapse seismic monitoring data than any other sites for tracking CO2 plume development, but significant uncertainties still exist for some reservoir parameters. In order to simulate CO2 plume migration and assess model uncertainties, we applied two multi-phase compositional simulators to the Sleipner Benchmark model for the uppermost layer (Layer 9) of the Utsira Sand and calibrated our model against the time-lapsed seismic monitoring data at the site from 1999 to 2010. Approximate match with the observed plume was achieved by introducing lateral permeability anisotropy, CH4 in the CO2 stream, and adjusting reservoir temperatures. Model-predicted gas saturation, thickness of the CO2 accumulation, and CO2 solubility in brine – none of them used as calibration metrics – were all comparable with interpretations of the seismic data in the literature.Hundreds of simulations of parameter sensitivity (pressure, temperature, feeders, spill rates, relative permeability curves, and CH4) showed that simulated plume extents are sensitive to permeability anisotropy, temperature, and CH4 but not sensitive to the other analyzed parameters. However, adjusting a single parameter within the reported range of values would not reproduce the north–south trending CO2 plume. It took a combination of permeability, CH4, and temperature adjustments to match simulated CO2 plume with seismic monitoring data. On the other hand, even with a range of uncertain modeling parameters, the predicted fate of CO2 fell within a narrow band, ∼93 ± 2% structural/hydrodynamic trapping and ∼7 ± 2% solubility trapping. The calibrated model is not unique. Other possibilities for reproducing the elongated plume such as a slight tilting of the caprock surface to the south and subtle geological features in the Layer 9 were not experimented with in this study, but are worthy of exploration for future studies. While it appears that we were able to reproduce the north–south elongated CO2 plume, which is a modest improvement over previous models, the adjustments of parameters need to be verified with new observations.

  • 1272.
    Ögren, Yngve
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science. RISE ETC.
    Camera and laser based diagnostics relevant for entrained flow gasifiers2018Licentiate thesis, comprehensive summary (Other academic)
  • 1273.
    Ögren, Yngve
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science. RISE ETC AB.
    Improving the efficiency of entrained flow gasifiers by real time in-situ diagnostics and burner design2019Doctoral thesis, comprehensive summary (Other academic)
  • 1274.
    Ögren, Yngve
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science. RISE-Energy Technology Center AB, Piteå, Sweden.
    Gullberg, Marcus
    RISE-Energy Technology Center AB, Piteå, Sweden.
    Wennebro, Jonas
    RISE-Energy Technology Center AB, Piteå, Sweden.
    Sepman, Alexey
    RISE-Energy Technology Center AB, Piteå, Sweden.
    Tóth, Pál
    RISE-Energy Technology Center AB, Piteå, Sweden. University of Miskolc, Department of Combustion and Thermal Energy, Miskolc-Egyetemváros, Miskolc, Hungary.
    Wiinikka, Henrik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science. RISE-Energy Technology Center AB, Piteå, Sweden.
    Influence of oxidizer injection angle on the entrained flow gasification of torrefied wood powder2018In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 181, p. 8-17Article in journal (Refereed)
    Abstract [en]

    In the present work, 5 different axisymmetric burners with different directions of the oxidizer inlets were experimentally tested during oxygen blown gasification of torrefied wood powder. The burners were evaluated under two different O2/fuel ratios at a thermal power of 135 kWth, based on the heating value of torrefied wood powder. The evaluation was based on both conventional methods such as gas chromatography measurements and thermocouples and in-situ measurements using Tunable Diode Laser Absorption Spectroscopy. It was shown that changes in the near burner region influence the process efficiency significantly. Changing the injection angle of the oxidizer stream to form a converging oxidizer jet increased process efficiency by 20%. Besides increased process efficiency, it was shown that improvements in burner design also influence carbon conversion and hydrocarbon production. The burner with the best performance also produced less CH4 and achieved the highest carbon conversion. The effect of generating swirl via rotating the oxidizer jet axes was also investigated. Swirl broadened or removed the impingement area between the fuel and oxidizer jets, however resulting in differences in performance within the measurement uncertainty. 

  • 1275.
    Ögren, Yngve
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Sepman, Alexey
    RISE-Energy Technology Center AB .
    Qu, Zhechao
    Umeå University, Thermochemical Energy Conversion Laboratory, Department of Applied Physics and Electronics.
    Schmidt, Florian M.
    Umeå University, Thermochemical Energy Conversion Laboratory, Department of Applied Physics and Electronics.
    Wiinikka, Henrik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Comparison of Measurement Techniques for Temperature and Soot Concentration in Premixed, Small-Scale Burner Flames2017In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 31, no 10, p. 11328-11336Article in journal (Refereed)
    Abstract [en]

    Optical and intrusive measurement techniques for temperature and soot concentration in hot reacting flows were tested on a small-scale burner in fuel-rich, oxygen-enriched atmospheric flat flames produced to simulate the environment inside an entrained flow reactor. The optical techniques comprised two-color pyrometry (2C-PYR), laser extinction (LE), and tunable diode laser absorption spectroscopy (TDLAS), and the intrusive methods included fine-wire thermocouple thermometry (TC) and electrical low pressure impactor (ELPI) particle analysis. Vertical profiles of temperature and soot concentration were recorded in flames with different equivalence and O2/N2 ratios. The 2C-PYR and LE data were derived assuming mature soot. Gas temperatures up to 2200 K and soot concentrations up to 3 ppmv were measured. Close to the burner surface, the temperatures obtained with the pyrometer were up to 300 K higher than those measured by TDLAS. Further away from the burner, the difference was within 100 K. The TC-derived temperatures were within 100 K from the TDLAS results for most of the flames. At high signal-to-noise ratio and in flame regions with mature soot, the temperatures measured by 2C-PYR and TDLAS were similar. The soot concentrations determined with 2C-PYR were close to those obtained with LE but lower than the ELPI results. It is concluded that the three optical techniques have good potential for process control applications in combustion and gasification processes. 2C-PYR offers simpler installation and 2D imaging, whereas TDLAS and LE provide better accuracy and dynamic range without calibration procedures.

  • 1276.
    Ögren, Yngve
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science. RISE-Energy Technology Center AB.
    Tóth, Pál
    RISE-Energy Technology Center AB.
    Garami, Attila
    University of Miskolc, Faculty of Material Sciences and Engineering, Institute of Energy and Quality Affairs, Department of Combustion Technology and Thermal Energy.
    Sepman, Alexey
    RISE-Energy Technology Center AB.
    Wiinikka, Henrik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science. RISE-Energy Technology Center AB.
    Development of a vision-based soft sensor for estimating equivalence ratio and major species concentration in entrained flow biomass gasification reactors2018In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 226, p. 450-460Article in journal (Refereed)
    Abstract [en]

    A combination of image processing techniques and regression models was evaluated for predicting equivalence ratio and major species concentration (H2, CO, CO2 and CH4) based on real-time image data from the luminous reaction zone in conditions and reactors relevant to biomass gasification. Two simple image pre-processing routines were tested: reduction to statistical moments and pixel binning (subsampling). Image features obtained by using these two pre-processing methods were then used as inputs for two regression algorithms: Gaussian Process Regression and Artificial Neural Networks. The methods were evaluated by using a laboratory-scale flat-flame burner and a pilot-scale entrained flow biomass gasifier. For the flat-flame burner, the root mean square error (RMSE) were on the order of the uncertainty of the experimental measurements. For the gasifier, the RMSE was approximately three times higher than the experimental uncertainty – however, the main source of the error was the quantization of the training dataset. The accuracy of the predictions was found to be sufficient for process monitoring purposes. As a feature extraction step, reduction to statistical moments proved to be superior compared to pixel binning.

  • 1277.
    Öhman, Marcus
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Boström, Dan
    Umeå universitet.
    Skoglund, Nils
    Umeå universitet.
    Grimm, Alejandro
    Boman, Christoffer
    Umeå universitet.
    Kofod-Hansen, Marie
    Torvforsk.
    Minskade askrelaterade driftsproblem genom inblandning av torv i åkerbränslen2010Report (Other academic)
    Abstract [sv]

    Torvbränslen används ofta i kombination med trädbränslen i värme- och kraftvärmeverk. Den kombinationen har visat sig ge förbränningstekniska fördelar kanske främst minskad risk för askrelaterade driftsproblem. Erfarenheter saknas dock vad gäller eventuella positiva sameldningseffekter/erfoderliga inblandningsgrader av torv i många kommande åkerbränslen såsom salix, rörflen och halm. Projektets mål har därför varit att: i) bestämma vilka typiska inblandningsgrader av torv i olika åkerbränslen (halm, salix och rörflen) som krävs för att uppnå positiva effekter m a p slaggning, beläggningsbildning/(högtemperaturkorrosion) och bäddagglomerering, samt ii) demonstrera möjligheterna att minska uppkomsten av askrelaterade driftsproblem i förbränningsanläggningar genom inblandning av torv till intressanta åkerbränslen. Termokemiska modellberäkningar utfördes för att bestämma effekter av torvinblandning till halm, salix och rörflen med hög och låg askhalt på reduktionen av slaggnings-, beläggningsbildnings-/(korrosion)- och bäddagglomereringsrisken vid förbränning. Dessa resultat och tidigare utförda försök i bänkskala låg sedan till grund för valda bränslekombinationer, torvinblandningsgrader och torvprov i de sedan utförda demonstrationsförsöken. Dessa demonstrationsförsök utfördes i en rosteranläggning på 4 MW (rörflen/rörflensmixar och salix/salixmixar) och i en pelletsbrännare/-panna i bänkskala (20 kW) (halm/halmmixar). Resultaten visar att inblandning av typisk starrbaserad bränntorv i salix och rörflen med låg askhalt ger positiva effekter vad avser bäddagglomerering och beläggningsbildning/(korrosion) i pannors konvektionsdelar redan vid relativt låga inblandningsgrader (15 vikts-% på TS basis). En starrbaserad bränntorv med relativt högt Ca/Si förhållande bör väljas för sameldning med salix i rosteranläggningar för att inte öka slaggningsrisken. Samma torvtyp kan också i rosteranläggningar nyttjas i sameldning med rörflen med låg askhalt (relativt låga inblandningsgrader räcker d v s 15 vikts-% på TS basis) och vetehalm (höga inblandningsgrader krävs d v s upp mot 40 vikts-% på TS basis) för att reducera slaggningsrisken. Vid val av torvslag för att maximera de ovanstående positiva effekterna vid förbränning kan därför en allmän rekommendation göras att torvar med hög askhalt (starrinnehållande torv), och gärna med högt inslag av svavel, ger de bästa sameldningsegenskaperna med det tilläget att vid rostereldning bör en torv med relativt högt Ca/Si förhållande väljas (gärna upp mot 1 på vikts-% basis). Rörflen med hög askhalt förväntas inte ge upphov till några större problem med beläggnings- och slaggnings-/bäddagglomereringsproblem och är därför i första hand inte intressant att samelda med torv utifrån ett askrelaterat driftsproblemperspektiv. För att reducera beläggningstendensen till låga nivåer vid sameldning med vetehalm krävs troligen så höga nivåer att detta inte är praktiskt intressant.

  • 1278.
    Öhman, Marcus
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Gilbe, Carl
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Näzelius, Ida-Linn
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Hedman, Henry
    Energy Technology Centre, Piteå.
    Boström, Dan
    Umeå universitet.
    Boman, Christoffer
    Umeå universitet.
    Backman, Rainer
    Umeå universitet.
    Slag formation during combustion of biomass fuels with low phosphorus content2011In: From research to industry and markets: proceedings ; 19th European Biomass Conference and Exhibition ; ICC Berlin, International Congress Center Berlin, Germany, conference 6 - 10 June 2011, exhibition 6 - 9 June 2011 / [ed] Martin Faulstich, Florence: ETA - Renewable Energies , 2011, p. 1267-1270Conference paper (Refereed)
    Abstract [en]

    Slag and ash deposition problems have more than occasionally been observed in biomass fueled plants in general and especially in pellet fired plants. These problems can lead to reduced accessibility as well as performance of the combustion appliances. Slag formation including ash transformation mechanisms, measures for prevention and prediction during combustion of biomass fuels has been studied by the research groups at Luleå University of Technology, Umeå University and Energy Technology Center for over one decade now. Several (about 40) different biomass fuels/fuel mixtures have been studied and many different fuel additives/co-combustion fuels have been used to combat slag formation. About 20 scientific papers and 10 technical reports have been published by the research groups within the topic of slag formation during combustion of biomass fuels with low phosphorus content. The objective of the present work was to summarize the general experiences and conclusions of our research within the area of slag formation during combustion of fuels with low phosphorus and varying silicon content. Silicon rich fuels, i.e. fuel ash dominated by silicate-alkali chemistry (e.g. straw fuels), generally shows relatively high slagging tendencies. Exceptions to these general trends exists i.e. fuels with very high Si/K-ratios. Wood derived fuels with a relatively low inherent silicon content shows low or relatively moderate slagging tendencies. However, severe contamination of sand material to woody biomass fuels may greatly enhance the slagging tendencies. Fuel additive addition to problematic woody biomass and straw significantly reduces the slagging tendencies. When adding limestone and kaolin to the problematic wood and straw fuels the composition of the formed slag is changed from relatively low temperature melting silicates to high temperature melting silicates and oxides. The standard ash fusion tests and chemical equilibrium calculations gives useful qualitatively information of the slagging tendencies. However, both methods must be further improved before quantitatively results can be used. The use of different fuel indexes to predict the slagging tendencies could be an interesting option. More research within this field is, however, needed.

  • 1279.
    Öhman, Marcus
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Gilbe, R
    Boman, C
    Erhardsson, T
    Pommer, L
    Boström, D
    Nordin, A
    Samuelsson, R
    Burvall, J
    Minskade askrelaterade driftsproblem via torv i biobränslen2007In: Nordisk Energi, ISSN 1654-0328, Vol. 6, p. 62-63Article in journal (Other (popular science, discussion, etc.))
  • 1280.
    Öhman, Marcus
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Nyström, Ida-Linn
    Gilbe, Carl
    Boström, Dan
    Umeå university.
    Lindström, Erica
    Umeå university.
    Boman, Christoffer
    Umeå university.
    Backman, Rainer
    Umeå university.
    Hedman, Henry
    Energy Technology Centre, Piteå.
    Samuelsson, Robert
    Swedish University of Agricultural Sciences.
    Burvall, Jan
    Swedish University of Agricultural Sciences.
    Shaojun, X
    Swedish University of Agricultural Sciences.
    Slag formation during combustion of biomass fuels2009Conference paper (Other academic)
    Abstract [en]

    Slag and ash deposition problems have more than occasionally been observed in biomass fueled plants in general and especially in pellet fired plants. These problems could lead to reduced accessibility as well as performance of the combustion appliances. Slag formation including measures for prevention and prediction during combustion of biomass fuels has been studied by the research groups at Luleå University of Technology, Umeå University, Energy Technology Center and Swedish University of Agricultural Sciences for about one decade know. Several (about 40) different biomass fuels/fuel mixtures have been studies and many different fuel additives/co-combustion fuels have been used to combat slag formation. About 25 scientific papers and 10 technical reports have been published by the research groups within the topic of slag formation during combustion of biomass fuels. The general experiences and conclusions of our research within the area will be presented.

  • 1281. Öhrman, Olov
    et al.
    Häggström, Caroline
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Wiinikka, Henrik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Hedlund, Jonas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Gebart, Rikard
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Analysis of trace components in synthesis gas generated by black liquor gasification2012In: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 102, p. 173-179Article in journal (Refereed)
    Abstract [en]

    The only pressurized black liquor gasifier currently in operation is located in Sweden. The composition of the main components in the gas has been reported previously. The main components are H2, CO, CO2, N2, CH4, and H2S. In the present work, trace components in the gas have been characterized and the results are hereby reported for the first time. Samples were taken at two occasions during a one year period. The benzene concentration in the gas varied only slightly and the average concentration was 158 ppm. Benzene is formed by thermal cracking of the biomass. The COS concentration varied substantially and the average concentration was 47 ppm. The variations may be related to how the quench is operated. A few ppm of C2-hydrocarbons were also observed in the gas and the variation was probably a result of varying oxygen to black liquor ratio. No tars were observed in the gas. However, tar compounds, such as phenanthrene, pyrene, fluoranthene and fluorene were detected in deposits found on the pipe walls after the gas cooler. The concentration of particles in the synthesis gas was very low; <0.1 mg/N m3, which is comparable to the particulate matter in ambient air. Submicron particles were comprised of elements such as C, O, Na, Si, S, Cl, K, and Ca, and these particles probably originated from the black liquor. Larger particles were comprised mainly of Fe, S and Ni and these particles probably resulted from corrosion of steel in the plant pipe-work. In summary, the concentrations of trace components and particles in the gas are quite low.

  • 1282. Öhrman, Olov
    et al.
    Weiland, Fredrik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Pettersson, Esbjörn
    Luleå University of Technology, Department of Engineering Sciences and Mathematics.
    Johansson, Ann-Christine
    Energy Technology Centre, Piteå.
    Hedman, Henry
    Energy Technology Centre, Piteå.
    Pedersen, Mads
    Biogasol, Lautrupvang 2A, 2750 Ballerup.
    Pressurized oxygen blown entrained flow gasification of a biorefinery lignin residue2013In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 115, p. 130-138Article in journal (Refereed)
    Abstract [en]

    Renewable fuels could in the future be produced in a biorefinery which involves highly integrated technologies. It has been reported that thermochemical conversion (gasification) of lignocellulosic biomass has a high potential for end production of renewable biofuels. In this work, lignin residue from biochemical conversion of wheat straw was gasified in an oxygen blown pressurized entrained flow gasifier (PEBG) at 0.25–0.30 MWth, 0.45 < λ < 0.5 and 1 bar (g). A video camera mounted inside the PEBG was used to observe the flame during start up and during operation. Hydrogen (H2), carbon monoxide (CO) and carbon dioxide (CO2) were the main gas components with H2/CO ratios varying during the gasification test (0.54–0.63). The methane (CH4) concentration also varied slightly and was generally below 1.7% (dry and N2 free). C2-hydrocarbons (< 1810 ppm) and benzene (< 680 ppm) were also observed together with low concentrations of hydrogen sulfide (H2S, < 352 ppm) and carbonyl sulfide (COS, < 131 ppm). The process temperature in the reactor was around 1200 °C. The slag seemed to consist of Cristobalite (SiO2) and Berlinite (AlPO4) and Na, Ca, Mg, K and Fe in lower concentrations. Cooling of the burner will be necessary for longer tests to avoid safety shut downs due to high burner temperature. The cold gas efficiency and carbon conversion was estimated but more accurate measurements, especially the syngas flow, needs to be determined during a longer test in order to obtain data on the efficiency at optimized operating conditions. The syngas has potential for further upgrading into biofuels, but will need traditional gas cleaning such as acid gas removal and water gas shifting. Also, higher pressures and reducing the amount of N2 is important in further work.

  • 1283.
    Örberg, Håkan
    et al.
    Sveriges Lantbruksuniversitet.
    Skoglund, Nils
    Umeå universitet.
    Grimm, Alejandro
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Boström, Dan
    Umeå universitet.
    Öhman, Marcus
    Teknikutveckling för ökad etablering och nyttjande av rörflen: demonstrationsförsök i fullskala2010Report (Other academic)
    Abstract [sv]

    Resultaten visar att energigräset rörflen kan utgöra ett kompletterande bränsle till det skogsbränsle och den torv som idag används i svenska värme- och kraftvärmeanläggningar. En inblandning av rörflen med ca 10 % på energibasis i en bränslemix som för övrigt består av 10-20 % carextorv och 70-80 % träbränsle har i demonstrationsförsök visat goda resultat. Denna bränslemix har vid fullskaliga förbränningsförsök i fluidiserande bädd (Hedensbyn,CFB 98 MW) under sammanlagt 4 dygn inte gett upphov till störningar eller negativa effekter på utrustning eller ökade utsläpp i rökgaserna i form av partiklar eller gasformiga emissioner. Vid simulerade påverkan på överhettare i form av kylda sonder har även konstaterats att beläggningstillväxten varit oförändrad och ej givit upphov till ökad korrosion. Inblandning i bränslemixen har skett med hackad rörflen (40-50 mm) i torvdelen för att en jämn inblandning kunde åstadkommas. Rörflensmaterialet har levererats i samband med skörden så att det hackats direkt på fältet med exakthack kopplad till vagn eller med containerhantering. Vid leverans under vår och försommar har rörflenen hållit mycket låg fukthalt med ett medel på 11,3 % fukt. Jämförande studier har gjorts med system där rörflen vid skörden under vår pressats till storbalar för vidare transport till terminal eller gårdscentrum. Detta system har visat sig mindre effektivt jämfört med direkthackning på fältet och transport av hackat material till värmeverk. En fördel med storbalssystemet är dock att det möjliggör mer kostnadseffektiv lagring utan att t.ex. fukthalten höjs under lagringstiden. Även vägtransport från terminal eller gårdscentrum till värmeverk har visat sig mer effektivt med storbalar jämfört med hackat material. Vid lastning av stora fyrkantsbalar (90x120x220 cm) på lastbil med släp uppnåddes i stort sett dubbla lastvikten jämfört med hackad rörflen (20,9 ton jmf. m. 11,0 ton). För de något mindre anläggningarna av typen rosterpannor som provats (0,6 och 4 MW) har den briketterade formen av rörflen använts för att uppnå en jämn och koncentrerad bränslematning. Även här har en blandning av rörflen och torv visat sig användbar och speciellt för rörflen med låg askhalt har torvinblandning på 15 vikts-% av gett minskad tendens till sintring av askan. Rörflen med hög askhalt (utan torvinblandning) har kunnat sameldas med träbränsle utan risk för sintrad aska i dessa anläggningar. Tillverkningen av briketter för försöken, sammanlagt ca 35 ton, varav hälften med inblandning av torv har genomförts utan störningar och med bra kvalité på briketterna.

  • 1284. Čundeva, S
    et al.
    Bollen, Math
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Kokolanski, Ž
    Vuletić, J
    Krkoleva, A
    Immunity against voltage dips: main recommendations to stakeholders of the CIGRE/CIRED/UIE Joint Working Group C4.1102011Conference paper (Refereed)
  • 1285. Čundeva, S
    et al.
    Bollen, Math
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Krkoleva, A
    Vuletić, J
    Kokolanski, Ž
    Djokić, S
    Improved understanding of compatibility issues regarding voltage dips: main contributions of the CIGRE/CIRED/UIE Joint Working Group C4.1102011Conference paper (Refereed)
23242526 1251 - 1285 of 1285
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