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  • 1.
    A., Trubetskaya
    et al.
    National University of Ireland Galway.
    G. R., Surup
    University of Agder.
    Forsberg, Fredrik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    T., Attard
    University of York.
    A., Hunt
    Khon Kaen University.
    V., Budarin
    University of York.
    V., Abdelsayed
    National Energy Technology Laboratory.
    D., Shekhawat
    National Energy Technology Laboratory.
    The Effect of Wood Composition and Supercritical CO2 Extraction on the Charcoal Production2019In: 2019 AIChE Annual Meeting proceedings, American Institute of Chemical Engineers, 2019, article id 552cConference paper (Other academic)
    Abstract [en]

    This work demonstrated that the coupling of supercritical carbon dioxide extraction with slow pyrolysis is effective to remove over half of extractives from low quality wood and to generate biochar from remaining solid wood fractions. The high yields of extractives from supercritical carbon dioxide extraction illustrates the potential utilizing of low quality wood as an alternative feedstock for the sustainable production of value-added chemicals. Results showed that supercritical carbon dioxide extraction has neither a strong impact on the physical properties of original wood nor on the yield of solid biochar. These results are promising as they show that the biochar obtained for this renewable feedstock could be used as an alternative to fossil-based coke in applications including ferroalloy industries. Moreover, the heat treatment temperature and supercritical carbon dioxide extraction had a significant impact on the tar yields, leading to the increase in naphthalene, polycyclic aromatic hydrocarbons, aromatic and phenolic fractions with the greater temperature. The differences in gasification reactivity and dielectric properties of solid biochars, composition and yields of liquid products of non-treated pinewood and extracted wood fraction emphasize the impact of supercritical carbon dioxide extraction on the pyrolysis process. 

  • 2.
    Bajracharya, Suman
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Sarkar, Omprakash
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Krige, Adolf
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Matsakas, Leonidas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Rova, Ulrika
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Christakopoulos, Paul
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Chapter 12 - Advances in gas fermentation processes2022In: Current Developments in Biotechnology and Bioengineering: Advances in Bioprocess Engineering / [ed] Sirohi, Ranjna; Pandey, Ashok; Taherzadeh, Mohammad J.; Larroche, Christian, Elsevier, 2022, p. 321-351Chapter in book (Other academic)
    Abstract [en]

    Microbial metabolism enables the sustainable synthesis of fuels and chemicals from gaseous substrates (H2, CO, and CO2), thus drastically diminishing the carbon load in the atmosphere. Various value-added biochemicals and biofuels, such as acetate, methane, ethanol, butanol, butyrate, caproate, and bioplastics, have been produced during the conversion of syngas or H2/CO2, using a variety of microorganisms as biocatalysts. Gas fermentation processes using acetogenic and methanogenic organisms are being extensively investigated. This chapter provides an overview of microbial CO and CO2 conversion technology, with an emphasis on recent developments and integration with renewable electricity for the generation of H2 or other forms of electron donors. A discussion on technological challenges in gas fermentation addresses issues, such as poor mass transfer, low microbial biomass, and low productivity. It also presents possible solutions based on the latest advances in bioelectrochemical processes including microbial gas electrofermentation. Finally, the chapter includes a sustainability analysis of the process and includes a brief update on commercially established companies operating gas fermentation systems. Overall, an integrated approach combining gas fermentation and renewable electricity offers an opportunity for the development of CO and CO2- based biochemical and biofuel production at commercial scale.

  • 3.
    Bäckebo, Markus
    Luleå University of Technology, Department of Engineering Sciences and Mathematics.
    The influence of particle size distribution on bio-coal gasification rate as related to packed beds of particles2020Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis is a part of a collaboration between Höganäs AB and Luleå University of Technology, aiming at replacing fossil process coal with bio-coal in their sponge iron process. The difference in gasification reactivity, i.e. reaction rate, between fossil coals and bio-coals is the major challenge in the endeavor to decrease the climate impact of the existing process. The goal of this thesis is to develop a model of reaction rate for bio-coals in relation to particle size distribution. Different particle size distributions were combined and tested to see how that affects the effective reaction rate.

    Within the scope of this work, gasification reactivities of different materials, including coal, cokes, and bio-coals, were determined. Three bio-coals were selected to study the effect of particle size distribution on reactivity. Kinetic parameters were determined by using thermogravimetric analysis in the temperature range of 770-850 °C while varying CO2 partial pressure between 0.1-0.4 atm. The effect of particle size on the reaction rate was investigated by using particles with diameter between 0.18 and 6.3 mm. The effect of particle size distribution on the reactivity of bio-coal in a packed bed was carried out in a macro thermogravimetric reactor with a constant bed volume of 6.5 cm3 at 980 °C and 40% (vol.) of CO2.

    The experimental investigation in three different rate-limiting steps was done for one bio-coal sample, i.e. Cortus Bark bio-coal. The activation energy of the bio-coal was 187 kJ mol-1, and the reaction order was 0.365. For the internal diffusion control regime, an increase in particle size resulted in low reaction rate. The effective diffusivity calculated from the Thiele modulus model was 1.41*10-5 m2 s-1. For the external diffusion control regime, an increase in particle size increased the reaction rate up to a certain point where it plateaued at >1 mm. By choosing two discrete particle size distributions, where a smaller average distribution can fit into a larger average distribution the reaction rate was lowered by 30% compared to only using a single narrow particle size distribution. This solution decreased the difference of apparent reaction rate in a packed bed between the bio-coal and anthracite from 6.5 times to 4.5 times.

    At the moment the model is not generalized for all bio-coals. However, the developed methodology can be routinely applied to assess the different bio-coal samples. One possible error can be that pyrolysis influences the gasification rate for bio-coal that is pyrolyzed below the temperature of the gasification test. There is a clear correlation between particle size distributions, bulk density, and apparent reactivity. By mixing two distributions the reaction rate of Cortus Bark was reduced from 6.5 times the reaction rate of anthracite to 4.5.

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  • 4.
    Böhlenius, Henrik
    et al.
    Southern Swedish Forest Research Centre, Swedish University of Agricultural Sciences, SE-234 56 Alnarp, Sweden.
    Öhman, Marcus
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Granberg, Fredrik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Persson, Per-Ove
    Persson f.N.B. AB, SE-54197, Lerdala, Sweden.
    Biomass production and fuel characteristics from long rotation poplar plantations2023In: Biomass and Bioenergy, ISSN 0961-9534, E-ISSN 1873-2909, Vol. 178, article id 106940Article in journal (Refereed)
    Abstract [en]

    One of the key elements in this transition is the securing of a large supply of sustainable biomass. In this study, the feedstock potential of long rotation poplar plantations (12–30 years with diameter of 15 of 30 cm) was determined and the properties of poplar biomass fuel were analyzed with the aim of using thermochemical conversion methods to produce biofuel. Our results demonstrate that Sweden has great potential for producing biofuels from long rotation poplar plantations, with a total of 1.8 million hectares (ha) consisting of arable (0.5 million ha) and forested arable land (1.3 million ha). Based on available land and biomass production potential, our results indicate that 10 million Mg DW could be produced annually. Regions in mid/southern Sweden have the largest potential (larger areas and higher biomass production. Our results further suggest that poplar biomass from these plantations has fuel characteristics similar to forest fuels from other conifer tree species, making the biomass suitable as feedstock for biofuel production based on thermochemical conversion methods. If 25% of the available land were used, 7.6 TWh methanol biofuels could be produced annually from 16 biofuel plants, using 160,000 Mg DW yr−1, primarily located in the southern part of Sweden. Two counties (Skåne and Västra Götaland) would be able to support their biofuel plants using poplar plantations as feedstock. Stable biofuel production in the other counties would depend on collaborating with neighboring counties.

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  • 5.
    Chang, Jo-Shu
    et al.
    Research Centre for Smart Sustainable Circular Economy, Tunghai 407, Taiwan; Department of Chemical and Materials Engineering, College of Engineering, Tunghai University, Taichung 407, Taiwan; Department of Chemical Engineering, National Cheng Kung University, Tainan 701, Taiwan.
    Show, Pau Loke
    Department of Chemical and Environmental Engineering, Faculty of Science and Engineering, University of Nottingham Malaysia, Broga Road, 43500 Semenyih, Selangor Darul Ehsan, Malaysia.
    Lee, Duu-Jong
    Department of Chemical Engineering, National Taiwan University, Taipei 10617, Taiwan.
    Christakopoulos, Paul
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Recent advances in lignocellulosic biomass refinery2022In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 347, article id 126735Article in journal (Other academic)
  • 6.
    Edgren, Aina
    et al.
    Chalmers University of Technology, Gothenburg, SE-41296, Sweden; Kanthal AB, Halstahammar, SE-73427, Sweden.
    Ström, Erik
    Kanthal AB, Halstahammar, SE-73427, Sweden.
    Qiu, Ren
    Chalmers University of Technology, Gothenburg, SE-41296, Sweden.
    Frisk, Lars
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Akhtar, Farid
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Hörnqvist Colliander, Magnus
    Chalmers University of Technology, Gothenburg, SE-41296, Sweden.
    High temperature deformation of polycrystalline C40 Mo(Si,Al)22022In: Materials Science & Engineering: A, ISSN 0921-5093, E-ISSN 1873-4936, Vol. 849, article id 143387Article in journal (Refereed)
    Abstract [en]

    Polycrystalline Mo(Si,Al) with C40 crystal structure was deformed in compression with a strain rate of 10−4 s−1 at 1300 °C. The specimens were deformed to a strain of 10%–15% and showed maximum stresses around 150 MPa prior to pronounced softening. No crack formation or significant increase in porosity could be observed. Post-test microstructure analysis revealed that the material was inhomogeneously deformed on both inter- and intragranular levels. Dynamic recrystallization occurred alongside low angle grain boundary formation in highly deformed grains. Furthermore, complex intragranular deformation fields suggest that slip systems other than ⟨2̄1̄10⟩ [0001] may be active during deformation.

  • 7.
    Faust, Robin
    et al.
    Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Kemigården 4, 412 96 Gothenburg, Sweden.
    Valizadeh, Ali
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Qiu, Ren
    Chalmers University of Technology, Department of Physics, Kemigården 1, Gothenburg, SE-41296, Sweden.
    Tormachen, Alyona
    Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Kemigården 4, 412 96 Gothenburg, Sweden.
    Maric, Jelena
    Division of Energy Technology, Department of Space, Earth, and Environment (SEE), Chalmers University of Technology, Gothenburg, 41296, Sweden.
    Berdugo Vilches, Teresa
    Division of Energy Technology, Department of Space, Earth, and Environment (SEE), Chalmers University of Technology, Gothenburg, 41296, Sweden.
    Skoglund, Nils
    Thermochemical Energy Conversion Laboratory, Department of Applied Physics and Electronics, Umeå University, SE-901 87 Umeå, Sweden.
    Seemann, Martin
    Division of Energy Technology, Department of Space, Earth, and Environment (SEE), Chalmers University of Technology, Gothenburg, 41296, Sweden.
    Halvarsson, Mats
    Chalmers University of Technology, Department of Physics, Kemigården 1, Gothenburg, SE-41296, Sweden.
    Öhman, Marcus
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Knutsson, Pavleta
    Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Kemigården 4, 412 96 Gothenburg, Sweden.
    Role of Surface Morphology on Bed Material Activation during Indirect Gasification of Wood2023In: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 333, Part 1, article id 126387Article in journal (Refereed)
    Abstract [en]

    Olivine and alkali-feldspar were utilized in separate campaigns in an indirect dual fluidized bed gasification campaign with woody biomass as fuel. After three days, both bed materials were reported to be active towards tar removal and exhibited oxygen-carrying abilities and had formed an ash layer consisting of an outer ash deposition layer and an inner interaction layer.

    X-ray microtomography analysis concluded that a preferred deposition of ash happens onto convex regions of the bed particles, which results in an increase in thickness of the ash layer over convex regions. This effect is most pronounced for the outer layer which is a product of ash deposition. The inner layer exhibits a homogeneous thickness and is probably formed by interaction of Ca from the outer layer with the particles. Transmission electron microscopy revealed the presence of Fe and Mn on the surface of the particles in a solid solution with Mg. The oxygen-carrying effect which is found for aged particles is therefore attributed to the presence of Fe and Mn on the surface of aged particles. Alkali were found on the surface of both particles which are likely contributing to the catalytic activity of the material towards tar removal.

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  • 8.
    Hedeler, Barbara
    et al.
    Chalmers University of Technology.
    Hellsmark, Hans
    Chalmers University of Technology.
    Söderholm, Patrik
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Social Sciences.
    Donner-Amnell, Jakob
    University of Eastern Finland.
    The dynamic between policy mixes and the emergence of sustainable value chains: Comparative perspectives from biofuel development in Finland and Sweden2020In: IST 2020: Book of Abstracts, IST 2020 , 2020, p. 283-283, article id 377Conference paper (Refereed)
    Abstract [en]

    This paper explores how the design of a policy mix and its characteristics affect the emergence and localization of industrialization processes over the lifecycle, from technology development to deployment of commercially established technologies. Combining insights from the literature on policy mixes for sustainability transitions, innovation systems, and technology lifecycles, a general framework is developed to explore the link between policy mixes and clean industry growth. The framework is applied to the empirical context of biofuels in two countries in a comparative case study setting over an extended period. The results reveal that there are great differences in which kinds of actors enter a new industry, the ways actors structure their activities over the lifecycle, and the policy incentives needed to spur emergence and functioning. Given the multi-actor and multi-technology complexity of clean industries, this paper concludes that policy needs to be aware of the fact that one specific policy mix may promote some actors and technologies more than others. The paper offers implications for innovation system scholars and policymakers.

  • 9.
    Kumar, A. Naresh
    et al.
    School of Civil and Environmental Engineering, Yonsei University, Seoul 03722, Republic of Korea; Department of Environmental Science and Technology, University of Maryland, College Park, MD 20742, USA.
    Sarkar, Omprakash
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Chandrasekhar, K.
    School of Civil and Environmental Engineering, Yonsei University, Seoul 03722, Republic of Korea.
    Raj, Tirath
    School of Civil and Environmental Engineering, Yonsei University, Seoul 03722, Republic of Korea.
    Narishetty, Vivek
    School of Water, Energy, and Environment, Cranfield University, Cranfield MK43 0AL, UK.
    Mohan, S. Venkata
    Bioengineering and Environmental Sciences Lab, Department of Energy and Environmental Engineering, CSIR-Indian Institute of Chemical Technology, Hyderabad 500 007, India.
    Pandey, Ashok
    Centre for Innovation and Translational Research, CSIR-Indian Institute of Toxicology Research, Lucknow, India.
    Varjani, Sunita
    Gujarat Pollution Control Board, Gandhinagar, Gujarat 382010, India.
    Kumar, Sunil
    CSIR-National Environmental Engineering Research Institute (CSIR-NEERI), Nagpur 440 020, India.
    Sharma, Pooja
    CSIR-National Environmental Engineering Research Institute (CSIR-NEERI), Nagpur 440 020, India.
    Jeon, Byong-Hun
    Department of Earth Resources and Environmental Engineering, Hanyang University, Seoul 04763, Republic of Korea.
    Jang, Min
    Department of Environmental Engineering, Kwangwoon University, Seoul 01897, Republic of Korea.
    Kim, Sang-Hyoun
    School of Civil and Environmental Engineering, Yonsei University, Seoul 03722, Republic of Korea.
    Upgrading the value of anaerobic fermentation via renewable chemicals production: A sustainable integration for circular bioeconomy2022In: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 806, part 1, article id 150312Article, review/survey (Refereed)
    Abstract [en]

    The single bioprocess approach has certain limitations in terms of process efficiency, product synthesis, and effective resource utilization. Integrated or combined bioprocessing maximizes resource recovery and creates a novel platform to establish sustainable biorefineries. Anaerobic fermentation (AF) is a well-established process for the transformation of organic waste into biogas; conversely, biogas CO2 separation is a challenging and cost-effective process. Biological fixation of CO2 for succinic acid (SA) mitigates CO2 separation issues and produces commercially important renewable chemicals. Additionally, utilizing digestate rich in volatile fatty acid (VFA) to produce medium-chain fatty acids (MCFAs) creates a novel integrated platform by utilizing residual organic metabolites. The present review encapsulates the advantages and limitations of AF along with biogas CO2 fixation for SA and digestate rich in VFA utilization for MCFA in a closed-loop approach. Biomethane and biohydrogen process CO2 utilization for SA production is cohesively deliberated along with the role of biohydrogen as an alternative reducing agent to augment SA yields. Similarly, MCFA production using VFA as a substrate and function of electron donors namely ethanol, lactate, and hydrogen are comprehensively discussed. A road map to establish the fermentative biorefinery approach in the framework of AF integrated sustainable bioprocess development is deliberated along with limitations and factors influencing for techno-economic analysis. The discussed integrated approach significantly contributes to promote the circular bioeconomy by establishing carbon-neutral processes in accord with sustainable development goals.

  • 10.
    Lindberg, Simon
    Luleå University of Technology, Department of Engineering Sciences and Mathematics.
    Förnybar gas för värmningsugnar i stålindustrin: Tekno-ekonomisk utvärdering av gasproduktion för SSAB Borlänge2019Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Sweden strives for a more and more sustainable society and aims to reach the net zero emissions of greenhouse gases to the atmosphere by 2045. Companies that operate in Sweden must therefore make major changes to achieve that goal. In this project, the possibility of replacing SSAB Borl¨anges fossil fuel needs in the hot-rolling process with gas from thermal gasification has been investigated. Through literature studies, needs analysis, calculations and modeling in Excel, four case studies with different gasification concepts have been evaluated. One major challenge has been to find solutions for handling the large heat loads in the hot-rolling furnaces. In the case studies, different strategies have been applied to address these; gas engines, balancing with a gasholder or upgrading to SNG that are stored in cryogenic containers. A case of purchasing biofuel-based liquid natural gas (bio-SNG) from external producers has also been evaluated. The technical feasibility as well as the financial stake and profit have been evaluated to find the best option. The case with the gasholder (Case 1b) showed the best economic performance with an IRR of 1.6%, a payback period of 21 years and manufacturing cost of 518 SEK/MWh. This is worse than the current solution, which costs 470 SEK/MWh. The most sensitive factors are the price of biomass and fossil fuels. The investment cost also has a great impact. A major advantage of the new solution is the reduction of SSAB’s use of fossil fuels with about 850 GWh being replaced by renewable gas.

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  • 11.
    Lundqvist, Petter
    Luleå University of Technology, Department of Engineering Sciences and Mathematics.
    Catalytic Hydrothermal Liquefaction of Waste Sludge: A Pre-study with Model Compounds2016Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The use and research of renewable fuels has become more important due to the connection between climate changes and the use of fossil fuels. With risks of decline in petroleum production derived from fossil fuels due to limitation of resources in the future, the renewable fuels are even more important in the transport sector.

    Research regarding gasification of biomass to create a syngas that can be upgraded to a biodiesel for cars is one of the approaches. By gasifying black liquor, it is possible to create a 100 % green fuel diesel. However, as this black liquor might be in limited quantities the idea to create a synthetic black liquor was sparked. The pulp industry where the black liquor originated from also has quantities of wastewater, containing a biomass sludge. Otherwise containing water in so large quantities that it is not possible to combust it without ending up with a negative energy output.

    One of the paths could be to recover the biomass from the sludge and convert it to a liquid similar to black liquor. Catalytic hydrothermal liquefaction has been recognized as a potential method. While biocrude is usually the target in hydrothermal liquefaction for direct upgrade to biofuel, the aqueous product could prove to be used for the gasification process. This would create a combined liquefaction-gasification process.

    Using model compounds possibly existing in the waste sludge, hydrothermal liquefaction was performed at different temperatures, together with varied alkali loads (K2CO3) and water the content to see how the different compounds reacted. Model compounds included cellulose and lignin as major compounds.

    Although the temperature was increased from 240 °C to 340 ° the lignin conversion was lower at 340 °C than at 240 °C. Re-polymerization took place and around 40 % of resulted in solid residue, while the remaining 60 % was partially converted to aqueous phase, oil phase or gas in the process. By not performing the hydrothermal liquefaction it is however possible to dissolve Kraft lignin directly in water and alkali.

    Cellulose showed an almost full conversion at 290 °C with similar results at 340 °C, with 4 – 5 % remaining as solid. At the higher temperature more gas was produced, which is not optimal for this process where liquid product is wanted. This suggest that 290 °C is enough for cellulose conversion in this process. Using an alkali load of 0.3 times the cellulose mass in the solution the final aqueous product contained about 26 % alkali, which is similar to black liquor. Increase the alkali to 0.9 times however increased the sought aqueous product, in both terms of energy and carbon content.

    Fiber sludge from a pulp mill, containing mainly cellulose, could therefore most likely be converted to a liquid product that is similar to black liquor for further upgrade

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  • 12.
    Ma, Charlie
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Aspects of Ash Transformations in Pressurised Entrained-Flow Gasification of Woody Biomass: Pilot-scale studies2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Pressurised entrained-flow gasification (PEFG) of woody biomass has the potential to produce high purity syngas for the production of vital chemicals, e.g., biofuels. However, ash-related issues such as reactor blockages and refractory corrosion need to be addressed before this potential can be realised from a technical perspective. These undesirable consequences can be brought about by slag formation involving inorganic ash-forming elements and the chemical transformations that they undergo during fuel conversion. The objective of this study was to elucidate the ash transformations of the major ash-forming elements and the slag formation process. A pilot-scale PEFG reactor was used as the basis of the study, gasifying different woody biomass-based fuels including wood, bark, and a bark/peat mixture. Different ash fractions were collected and chemically analysed. Reactor slags had elemental distributions differing from that of the fuel ash, indicating the occurrence of fractionation of ash material during fuel conversion. Fly ash particles from a bark campaign were also heterogeneous with particles exhibiting differing compositions and physical properties; e.g., molten and crystalline formations. Si was consistently enriched in the reactor slags compared to other major ash-forming elements, while analyses of other ash fractions indicated that K was likely volatilised to a significant extent. In terms of slag behaviour, near-wall temperatures of approximately 1050-1200 °C inside the reactor were insufficient to form flowing ash slag for continuous extraction of ash material during firing the woody biomass fuels alone. However, fuel blending of a bark fuel with a silica-rich peat changed the chemical composition of the reactor slags and bulk slag flow behaviour was evident. Thermochemical equilibrium calculations supported the importance of Si in melt formation and in lowering solidus and liquidus temperatures of Ca-rich slag compositions that are typical from clean wood and bark. Viscosity estimations also showed the impact that solids have upon slag flow behaviour and corresponded qualitatively to the experimental observations. Corrosion of reactor refractory was observed. The mullite-based refractory of the reactor formed a slag with the fuel ash slag, which caused the former to flux away. Reactor blockages were also resultant because of the high viscosity of this slag near the outlet.  A preliminary study into the corrosion of different refractories was also carried out, based on firing a bark/peat mixture.  Alumina-rich refractories consisting of corundum, hibonite, mullite, and andalusite tended to form anorthite and exhibited varying degrees of degradation. Infiltration of slag was evident for all the samples and was a severe mode of degradation for some refractories. For fused-cast periclase and spinel-based refractories, slag infiltration was limited to voids and no extensive signs of refractory dissolution were found. This is also supported by a thermochemical equilibrium calculations mimicking slag infiltration that incorporated viscosity estimations. The findings from this thesis contribute towards the development of woody biomass PEFG by highlighting issues concerning ash fractionation, slag behaviours and ash\slash refractory interaction that should be investigated further.

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  • 13.
    Matsakas, Leonidas
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Nitsos, Christos
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Vörös, Dimitrij
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Rova, Ulrika
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Christakopoulos, Paul
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    High-Titer Methane from Organosolv-Pretreated Spruce and Birch2017In: Energies, E-ISSN 1996-1073, Vol. 10, no 3, article id 263Article in journal (Refereed)
    Abstract [en]

    The negative impact of fossil fuels and the increased demand for renewable energy sources has led to the use of novel raw material sources. Lignocellulosic biomass could serve as a possible raw material for anaerobic digestion and production of biogas. This work is aimed at using forest biomass, both softwood (spruce) and hardwood (birch), as a raw material for anaerobic digestion. We examined the effect of different operational conditions for the organosolv pretreatment (ethanol content, duration of treatment, and addition of acid catalyst) on the methane yield. In addition, we investigated the effect of addition of cellulolytic enzymes during the digestion. We found that inclusion of an acid catalyst during organosolv pretreatment improved the yields from spruce, but it did not affect the yields from birch. Shorter duration of treatment was advantageous with both materials. Methane yields from spruce were higher with lower ethanol content whereas higher ethanol content was more beneficial for birch. The highest yields obtained were 185 mL CH4/g VS from spruce and 259.9 mL CH4/g VS from birch. Addition of cellulolytic enzymes improved these yields to 266.6 mL CH4/g VS and 284.2 mL CH4/g VS, respectively.

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  • 14.
    Muraleedharan, Madhu Nair
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Depolymerization of Lignocellulose by Lytic Polysaccharide MonoOxygenases2018Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Lignocellulose biomass is considered as one of the most potential and sustainable sources for the production of value-added chemicals and fuels while replacing the traditional petroleum resources. In a biorefinery, by employing biochemical conversion processes,cellulose present in the biomass is broken down into monomeric sugars which can belater converted into fuels or chemicals. This process is done with the help of different cellulose digesting enzymes (cellulases), isolated from natural cellulolytic organisms suchas saprophytic fungi.

    Lytic polysaccharide monooxygenases (LPMOs) are considered as one of the vital classesof enzymes in the bio-conversion of lignocellulose. They are copper active enzymes present naturally in cellulose degrading fungi. Unlike the traditional cellulases, they havea unique way of breaking cellulose using molecular oxygen or hydrogen peroxide as cosubstratein the presence of a reducing agent. Their ability to enhance the action of other cellulases in depolymerizing the cellulose, make them an integral part of today’s commercial cellulase cocktails.

    This thesis comprises the study about the action of lytic polysaccharide monooxygenaseson various cellulose substrates, both model and natural. The first part of the thesis focuses on the ability of an LPMO (MtLPMO9) and a traditional cellulase (MtEG5A), to act insynergism. The evaluation was done based on the release of oxidized and non-oxidized sugars and also on the ability to liquefy the substrates. It was observed that together, these two enzymes resulted in enhanced release of oxidized and non-oxidized sugars. Both were able to reduce viscosity of the substrates but no further synergistic effect was observed when added together.

    The second part focuses on the ability of LPMOs to accept electrons from lignins for their action of breaking cellulose chains. Three LPMOs, MtLPMO9, PcLPMO9D and NcLPMO9C, lignins from agricultural and forest biomass pretreated by various pretreatment methods were selected. It was demonstrated that lignins, both in isolatedand substrate bound form were able to act indirectly as reducing agents, by releasingsoluble low-molecular-weight molecules that act as mediators between enzyme and bulklignins. The structural and compositional properties of lignins also affected their ability toact as electron donors. In addition, the effect of biomass pretreatment methods on the lignin properties was also studied. The lignins from acid catalyzed organosolv pretreatment were found as the best candidates in supplying electrons to the enzymes.Interestingly, NcLPMO9C was not able to utilize lignins as electron donors requiring further investigation on their mechanism both in vivo and in vitro.

  • 15.
    Olofsson, Oscar
    Luleå University of Technology, Department of Engineering Sciences and Mathematics. Höganäs AB.
    Biochar in the Höganäs sponge iron process – techno-economic analysis of integrated production2018Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Biomass-based reducing agents have a potential to substitute fossil reducing agents in the steel industry. However, the industrial use of biomass-based reducing agents is currently in an early stage of development and has not yet been considered as a means to reduce fossil CO2 emissions, even though the use of fossil-based reducing agents for the iron and steel making cause the highest share of CO2 emissions. This master thesis presents a techno-economic analysis of a 10 MW biochar production plant integrated with sponge iron production in Höganäs. In this study, a steady-state process model was developed, where state-of-the-art research and development in biochar production for increased biochar yield was applied and adapted, using the principle of bio-oil recycle. The developed process model was used to evaluate the biochar production plant, in terms of conversion efficiency, production costs and CO2 emissions, for different process configurations. The results show that bio-oil recycle with 20 wt.% bio-oil increases the energy yield of biochar with 14%. However, it was found that bio-oil recycle increases the required heat input of pyrolysis which led to reduced plant efficiency with 4%-units and increased biochar production costs of 500-1000 SEK/ton biochar. It was found that system integration with Höganäs can reduce the production cost of biochar from over 5000 SEK/ton to under 2000 SEK/ton, where the most significant integration aspect was flue gas integration. The sensitivity analysis showed that the cost of biomass feedstock and total capital investment were the most sensitive input parameters. It was found that system integration with Höganäs was essential to achieve production costs of biochar below the price of fossil reducing agents. It was also found that co-produced bio-oil becomes a main product, essential for the economic performance of the biochar plant, even though the intended main product was the biochar.

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  • 16.
    Patel, Alok
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Sharma, Amit KumarCentre of Alternate Energy Research at the University of Petroleum and Energy Studies, Dehradun, Uttarakhand, India.
    Renewable Energy Innovations: Biofuels, Solar, and Other Technologies2023Collection (editor) (Other academic)
  • 17.
    Phounglamcheik, Aekjuthon
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Pitchot, Romain
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Andefors, Alf
    Future Eco North Sweden AB.
    Norberg, Niclas
    Future Eco North Sweden AB.
    Umeki, Kentaro
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Production of metallurgical charcoal from biomass pyrolysis: pilot-scale experiment2018Conference paper (Refereed)
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  • 18.
    Phounglamcheik, Aekjuthon
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Wang, Liang
    SINTEF Energy Research .
    Romar, Henrik
    University of Oulu, Research Unit of Applied Chemistry.
    Broström, Markus
    Umeå University, Department of Applied Physics and Electronics.
    Ramser, Kerstin
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Skreiberg, Øyvind
    SINTEF Energy Research .
    Umeki, Kentaro
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Effects of pyrolysis oil recycling and reaction gas atmosphere on the physical properties and reactivity of charcoal from wood2018Conference paper (Refereed)
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  • 19.
    Sartaj, Km
    et al.
    Department of Biosciences and Bioengineering, Indian Institute of Technology Roorkee, Roorkee 247667, Uttarakhand, India.
    Patel, Alok
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Matsakas, Leonidas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Prasad, Ramasare
    Department of Biosciences and Bioengineering, Indian Institute of Technology Roorkee, Roorkee 247667, Uttarakhand, India.
    Unravelling Metagenomics Approach for Microbial Biofuel Production2022In: Genes, ISSN 2073-4425, E-ISSN 2073-4425, Vol. 13, no 11, article id 1942Article, review/survey (Refereed)
    Abstract [en]

    Renewable biofuels, such as biodiesel, bioethanol, and biobutanol, serve as long-term solutions to fossil fuel depletion. A sustainable approach feedstock for their production is plant biomass, which is degraded to sugars with the aid of microbes-derived enzymes, followed by microbial conversion of those sugars to biofuels. Considering their global demand, additional efforts have been made for their large-scale production, which is ultimately leading breakthrough research in biomass energy. Metagenomics is a powerful tool allowing for functional gene analysis and new enzyme discovery. Thus, the present article summarizes the revolutionary advances of metagenomics in the biofuel industry and enlightens the importance of unexplored habitats for novel gene or enzyme mining. Moreover, it also accentuates metagenomics potentials to explore uncultivable microbiomes as well as enzymes associated with them.

  • 20.
    Xiong, S.
    et al.
    Swedish University of Agricultural Sciences, Department of Forest Biomaterial and Technology, Umeå, Sweden.
    Martín, C.
    Umeå University, Department of Chemistry, Umeå, Sweden.
    Eilertsen, L.
    Swedish University of Agricultural Sciences, Department of Forest Biomaterial and Technology, Umeå, Sweden. Swedish University of Agricultural Sciences, Department of Forest Genetics and Plant Physiology, Umeå Plant Science Center, Umeå, Sweden.
    Wei, M.
    Swedish University of Agricultural Sciences, Department of Forest Biomaterial and Technology, Umeå, Sweden. Guangxi University, College of Agronomy, Nanning, China.
    Myronycheva, Olena
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering. Swedish University of Agricultural Sciences, Department of Forest Biomaterial and Technology, Umeå, Sweden.
    Larsson, S.H.
    Swedish University of Agricultural Sciences, Department of Forest Biomaterial and Technology, Umeå, Sweden.
    Lestander, T.A.
    Swedish University of Agricultural Sciences, Department of Forest Biomaterial and Technology, Umeå, Sweden.
    Atterhem, L.
    Biosteam AB, Burträsk, Sweden.
    Jönsson, L.J.
    Umeå University, Department of Chemistry, Umeå, Sweden.
    Energy-efficient substrate pasteurisation for combined production of shiitake mushroom (Lentinula edodes) and bioethanol2019In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 274, p. 65-72Article in journal (Refereed)
    Abstract [en]

    Hot-air (75 -100°C) pasteurisation (HAP) of birch-wood-based substrate was compared to conventional autoclaving (steam at 121 °C) with regard to shiitake growth and yield, chemical composition of heat-pretreated material and spent mushroom substrate (SMS), enzymatic digestibility of glucan in SMS, and theoretical bioethanol yield. Compared to autoclaving, HAP resulted in faster mycelial growth, earlier fructification, and higher or comparable fruit-body yield. The heat pretreatment methods did not differ regarding the fractions of carbohydrate and lignin in pretreated material and SMS, but HAP typically resulted in lower fractions of extractives. Shiitake cultivation, which reduced the mass fraction of lignin to less than half of the initial without having any major impact on the mass fraction of glucan, enhanced enzymatic hydrolysis of glucan about four-fold. The choice of heating method did not affect enzymatic digestibility. Thus, HAP could substitute autoclaving and facilitate combined shiitake mushroom and bioethanol production.

  • 21.
    Zetterholm, Jonas
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Forest based biorefinery supply chains - Identification and evaluation of economic, CO2, and resource efficiency2018Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

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

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

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

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

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

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

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  • 22.
    Zetterholm, Jonas
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Bryngemark, Elina
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Social Sciences.
    Ahlström, Johan
    Department of Space, Earth and Environment, Division of Energy Technology, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden.
    Söderholm, Patrik
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Social Sciences.
    Harvey, Simon
    Department of Space, Earth and Environment, Division of Energy Technology, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden.
    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, Austria.
    Economic Evaluation of Large-Scale Biorefinery Deployment: A Framework Integrating Dynamic Biomass Market and Techno-Economic Models2020In: Sustainability, E-ISSN 2071-1050, Vol. 12, no 17, article id 7126Article in journal (Refereed)
    Abstract [en]

    Biofuels and biochemicals play significant roles in the transition towards a fossil-free society. However, large-scale biorefineries are not yet cost-competitive with their fossil-fuel counterparts, and it is important to identify biorefinery concepts with high economic performance. For evaluating early-stage biorefinery concepts, one needs to consider not only the technical performance and process costs but also the economic performance of the full supply chain and the impacts on feedstock and product markets. This article presents and demonstrates a conceptual interdisciplinary framework that can constitute the basis for evaluations of the full supply-chain performance of biorefinery concepts. This framework considers the competition for biomass across sectors, assumes exogenous end-use product demand, and incorporates various geographical and technical constraints. The framework is demonstrated empirically through a case study of a sawmill-integrated biorefinery producing liquefied biomethane from forestry and forest industry residues. The case study results illustrate that acknowledging biomass market effects in the supply chain evaluation implies changes in both biomass prices and the allocation of biomass across sectors. The proposed framework should facilitate the identification of biorefinery concepts with a high economic performance which are robust to feedstock price changes caused by the increase in biomass demand.

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