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  • 1.
    Anugwom, Ikenna
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen. Laboratory of Industrial Chemistry and Reaction Engineering, Process Chemistry Centre, Åbo Akademi University, Åbo-Turku FI-20500, Finland.
    Rujana, L.
    Wärnå, J.
    Hedenström, Mattias
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Mikkola, Jyri-Pekka
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen. Laboratory of Industrial Chemistry and Reaction Engineering, Process Chemistry Centre, Åbo Akademi University, Åbo-Turku FI-20500, Finland.
    In quest for the optimal delignification of lignocellulosic biomass using hydrated, SO2 switched DBU MEASIL switchable ionic liquid2016Ingår i: Chemical Engineering Journal, ISSN 1385-8947, E-ISSN 1873-3212, Vol. 297, s. 256-264Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this paper, various process parameters aiming at optimal short-time-high-temperature (STHT) process were studied upon fractionation of Nordic woody biomass into its primary constituents. Highly diluted, aqueous 'SO2-switched' switchable ionic liquid (SIL) based on an alkanol amine (monoethanol amine, MEA) and an organic superbase (1,8-diazabicyclo-[5.4.0]-undec-7-ene, DBU) was applied. The ultimate goal was to develop a more sustainable, environmentally friendly and cost efficient systems for efficient separation of the lignocellulosic fractions. One of the main products from the SIL fractionation is cellulose-rich pulp with very low lignin content, complemented with hemicelluloses. The NMR results reveal that substantial removal of lignin occurs even when relatively low amount of SIL was used. Further, a simple mathematical model describing the dissolution of the lignocellulose components (hemicellulose and lignin) and weight loss of wood as a function of time is described. Moreover, the most efficient process involved the use of SpinChem (R) rotating bed reactor while upon use of a flow through (loop) reactor, promising results were obtained at a treatment time of 4 h. Still, all the reactor systems studied gave rise to a rather low removal of hemicelluloses which mean that the solvent system is primary selective towards lignin dissolution.

  • 2. Berglund, Linn
    et al.
    Anugwom, Ikenna
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen. Laboratory of Industrial Chemistry and Reaction Engineering, Johan Gadolin Process Chemistry Centre, Åbo Akademi University, Turku, Finland.
    Hedenström, Mattias
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Aitomäki, Yvonne
    Mikkola, Jyri-Pekka
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen. Laboratory of Industrial Chemistry and Reaction Engineering, Johan Gadolin Process Chemistry Centre, Åbo Akademi University, Turku, Finland.
    Oksman, Kristiina
    Switchable ionic liquids enable efficient nanofibrillation of wood pulp2017Ingår i: Cellulose, ISSN 0969-0239, E-ISSN 1572-882X, Vol. 24, nr 8, s. 3265-3279Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Use of switchable ionic liquid (SIL) pulp offers an efficient and greener technology to produce nanofibers via ultrafine grinding. In this study, we demonstrate that SIL pulp opens up a mechanically efficient route to the nanofibrillation of wood pulp, thus providing both a low cost and chemically benign route to the production of cellulose nanofibers. The degree of fibrillation during the process was evaluated by viscosity and optical microscopy of SIL treated, bleached SIL treated and a reference pulp. Furthermore, films were prepared from the fibrillated material for characterization and tensile testing. It was observed that substantially improved mechanical properties were attained as a result of the grinding process, thus signifying nanofibrillation. Both SIL treated and bleached SIL treated pulps were fibrillated into nanofibers with fiber diameters below 15 nm thus forming networks of hydrophilic nature with an intact crystalline structure. Notably, it was found that the SIL pulp could be fibrillated more efficiently than traditional pulp since nanofibers could be produced with more than 30% less energy when compared to the reference pulp. Additionally, bleaching reduced the energy demand by further 16%. The study demonstrated that this switchable ionic liquid treatment has considerable potential in the commercial production of nanofibers due to the increased efficiency in fibrillation.

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  • 3. Biasi, Pierdomenico
    et al.
    Serna, Juan Garcia
    Salmi, Tapio O.
    Mikkola, Jyri-Pekka
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen. Department of Chemical Engineering, Process Chemistry Centre (PCC), Laboratory of Industrial Chemistry and Reaction Engineering, Åbo Akademi University, ÅBO-TURKU, Finland.
    Hydrogen Peroxide Direct Synthesis: Enhancement of Selectivity and Production with non-Conventional Methods2013Ingår i: ICHEAP-11: 11TH INTERNATIONAL CONFERENCE ON CHEMICAL AND PROCESS ENGINEERING, PTS 1-4 / [ed] Pierucci, S, Klemes, JJ, AIDIC - associazione italiana di ingegneria chimica, 2013, s. 673-678Konferensbidrag (Refereegranskat)
    Abstract [en]

    The present work is part of a comprehensive study on the direct synthesis of hydrogen peroxide in different fields, from chemistry to chemical engineering. Working on the different fields of the direct synthesis gave the possibility to look at the results and the challenges from different viewpoints. Here was investigated one parameter that enhances the direct synthesis. The H-2/Pd ratio is the key parameter that has to be investigated and optimize to enhance the hydrogen peroxide direct synthesis. Two reactors were built to study deeply the H-2/Pd ratio and to demonstrate how this parameter can affect the direct synthesis both in batch and continuous reactor with non-conventional experiments/methods. 1) A batch reactor was utilized as a "starving reactor" to enhance the productivity of hydrogen peroxide and to try to keep constant the selectivity. The starving method consists in refilling the hydrogen when it is consumed in the reactor. 2) A trickle bed reactor was utilized with a gradient of catalyst along the reactor to maximize both production and selectivity of hydrogen peroxide. The distribution of the catalyst along the bed gave the possibility to significantly improve the selectivity and the production of hydrogen peroxide (up to 0.5% in selected conditions). Higher production rate and selectivity were found when the catalyst concentration decreases along the bed from the top to the bottom compared to the uniformly dispersed catalyst. Selectivity in the batch reactor was enhanced by 5% and in the continuous reactor of 10%. The non-conventional experimental methods have been found to be novelty concepts to enhance the hydrogen peroxide direct synthesis.

  • 4.
    Björnwall, Erik
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Impact of calcination temperature and time on quicklime slaking reactivity2021Självständigt arbete på avancerad nivå (yrkesexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    In this master thesis work calcination parameters' impact on the resulting quicklimes slaking reactivity is investigated. This is done by calcination of three different sedimentary limestones in an N2 atmosphere according to a design of experiment matrix. The limestones are from Wolica Poland, Slite Sweden and Jutjärn Sweden. The temperatures and residence times are varied between 1000ºC, 1050ºC, and 1100ºC for 5 min, 27.5 min, and 60 min. There were seven experiments per limestone sample. The calcination experiments were conducted in an electrical muffle furnace.When the limestone samples were calcined, the resulting quicklimes slaking reactivity was tested according to standard SS-EN 459-2:2010 Building lime - Part 2: Test methods. Four different parameters were used to determine the slaking reactivity, these were the maximum temperature, how much the temperature increases under the initial 30 s, the time it takes for the temperature to reach 60ºC, and the time for the slaking to become 80% finished.From the slaking reactivity experiments, the calcination parameters to produce the most reactive quicklime for the limestone from Wolica and Jutjärn are 1000ºC for 60 min, and for the limestone from Slite 1100ºC for 5 min. For all three limestones the least reactive quicklime was received by calcining at 1100ºC for 60 min. The most and least reactive quicklimes were analyzed in SEM, where it could be seen that the least reactive quicklime samples were coarser compared to the most reactive samples. Depending on what slaking reactivity parameter is of interest, the calcination settings should be different and can be an indication for operation parameters for industrial kilns. The statistical analysis on the experimental model showed that the experiment had a poor statistical fit for most of the experiment. This could be due to that the model possibly was too simple to describe the calcination parameters complex impact on the slaking reactivity.

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  • 5.
    Bui, Thai Q.
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Konwar, Lakhya Jyoti
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Samikannu, Ajaikumar
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Nikjoo, Dariush
    Division of Materials Science, Luleå University of Technology, Luleå, Sweden.
    Mikkola, Jyri-Pekka
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen. Laboratory of Industrial Chemistry and Reaction Engineering, Johan Gadolin Process Chemistry Centre, Åbo Akademi University, Turku, Finland.
    Mesoporous Melamine-Formaldehyde Resins as Efficient Heterogeneous Catalyst for Continuous Synthesis of Cyclic Carbonates from Epoxides and gaseous CO22020Ingår i: ACS Sustainable Chemistry and Engineering, E-ISSN 2168-0485, Vol. 8, nr 34, s. 12852-12869Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Herein we report the application of inexpensive mesoporous melamine-formaldehyde resins (MMFR and MMFR250) obtained by a novel template-free and organosolvent-free hydrothermal method as efficient heterogeneous catalysts for direct synthesis of cyclic carbonates from CO2 and epoxides (epichlorohydrin, butylene oxide and styrene oxide). The catalytic activity of the melamine resins was attributed to the abundant Lewis basic N-sites capable of activating CO2 molecules. Based on CO2-Temperature programmed desorption, the concentration of surface basic sites for MMFR and MMFR250 were estimated to be 172 and 56 µmol/g, while the activation energy of CO2 desorption (strength of basic sites) were calculated to be 92.1 and 64.5 kJ/mol. We also observed considerable differences in the catalytic activity and stability of polymeric catalysts in batch and in continuous-flow mode; due to the existence of a synergism between adsorption of CO2 and cyclic carbonates (poison). Our experiments also revealed important role of catalyst surface chemistry and CO2 partial pressure upon catalyst poisoning. Nevertheless, owing to their unique properties (large specific surface area, large mesoporous and CO2 basicity) melamine resins presented excellent activity (turnover frequency 207-2147 h-1), selectivity (>99%) for carbonation of epoxides with CO2 (20 bar initial CO2 or CO2:epoxide mole ratio ~1.5) under solvent-free and co-catalyst-free conditions at 100-120 oC. Most importantly, these low-cost polymeric catalysts were reusable and demonstrated exceptional stability in a flow reactor (tested upto 13 days time on stream, weight hourly space velocity 0.26-1.91 h-1) for continuous cyclic carbonate production from gaseous CO2 with different epoxides (conversion 76-100% and selectivity >99%) under industrially relevant conditions (120 oC, 13 bar, solvent-free/co-catalyst-free) confirming their superiority over the previously reported catalytic materials.

  • 6. Carlsson, Per
    et al.
    Ma, Charlie
    Luleå University of Technology, Energy Engineering, Division of Energy Science, SE-971 87, Luleå, Sweden.
    Molinder, Roger
    Weiland, Fredrik
    Wiinikka, Henrik
    Öhman, Marcus
    Öhrman, Olov
    Slag Formation During Oxygen Blown Entrained-Flow Gasification of Stem Wood2014Ingår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 28, nr 11, s. 6941-6952Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Stem wood powders were fired in a mullite-lined pilot-scale oxygen-blown pressurized entrained-flow gasifier. During repeated campaigns involving increases in fuel load and process temperature, slag formations that eventuated in the blockage of the gasifier outlet were observed. These slags were retrieved for visual and chemical characterization. It was found that the slags had very high contents of Al and, in particular, high Al/Si ratios that suggest likely dissolution of the mullite-based refractory of the gasifier lining due to interactions with the fuel ash. Possible causes for the slag formation and behavior are proposed, and practical implications for the design of future stem wood entrained-flow gasifiers are also discussed

  • 7.
    Conte, Ricardo Pezoa
    et al.
    Industrial Chemistry and Reaction Engineering Johan Gadolin Process Chemistry Centre, Åbo Akademi University, Åbo-Turku, Finland.
    Ravanal, M. Cristina
    Centre for Biochemical Engineering and Biotechnology, Department of Chemical Engineering and Biotechnology, University of Chile, Santiago, Chile.
    Mäki-Arvela, Päivi
    Industrial Chemistry and Reaction Engineering Johan Gadolin Process Chemistry Centre, Åbo Akademi University, Åbo-Turku, Finland.
    Willför, Stefan
    Wood and Paper Chemistry Johan Gadolin Process Chemistry Centre, Åbo Akademi University, Åbo-Turku, Finland.
    Lienqueo, M. Elena
    Centre for Biochemical Engineering and Biotechnology, Department of Chemical Engineering and Biotechnology, University of Chile, Santiago, Chile.
    Mikkola, Jyri-Pekka
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen. Industrial Chemistry and Reaction Engineering Johan Gadolin Process Chemistry Centre, Åbo Akademi University, Åbo-Turku, Finland.
    Bioethanol production from the green alga ulva rigida and the brown algae macrocystis pyrifera2015Ingår i: NWBC 2015: the 6th Nordic Wood Biorefinery Conference, VTT Technical Research Centre of Finland , 2015, s. 319-325Konferensbidrag (Refereegranskat)
    Abstract [en]

    Macroalgae are suitable bioresources to be explored as raw material for bioethanol production, as about 40 wt.% of its mass is composed of carbohydrates and they completely lack lignin. In this work the simultaneous saccharification and fermentation (SSF) of the green alga Ulva rigida and the brown alga Macrocystis pyrifera was performed. The algae were initially pretreated in deionized water or diluted sulfuric acid at 125°C in an autoclave for 60 min, respectively. Commercial cellulolytic enzymes and yeast were used for ethanol production. The carbohydrate composition of the fresh alga, pretreated alga and glucose and ethanol concentrations in the SSF processing are given. The water pretreatment solubilized 82 wt.% of the ulvan (rhamno-glucuroxylan) contained in U. rigida and 73 wt.% of the glucan remained in the residue. The diluted acid treatment removed 93 wt.% of the carbohydrates contained in U. rigida. The SSF of U. rigida pretreated with water produced 0.47 g EtOH/g sugar, with a 92 wt.% theoretical yield. In turn, water and diluted acid pretreatment of M. pyrifera increased 8.4 and 14.8 fold the carbohydrate content in the pretreated alga compared to the SSF of the fresh alga. The SSF of M. pyrifera pretreated with dilute sulfuric acid produced 0.15 g EtOH/g sugar, 29 wt.% theoretical yield. The production of ethanol was demonstrated for U. rigida and M. pyrifera with mild pretreatments. Especially in case of U. rigida simple water treatment allows to isolate ulvan for other purposes and efficiently ferment the remaining fibers.

  • 8.
    Dannelind, Filip
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Hydrogen on demand for vessels: Using ammonia for hydrogen storage2022Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    The use of an ammonia and hydrogen mixture in an internal combustion engine has previously been tested.  Limited number of studies have been done on how such a system efficiently can be adopted onboard a vessel and remain competitive to today’s fossil power solutions. A literature study was done to evaluate different aspect of the study such as what concentrations of ammonia and hydrogen that could be usable for an internal combustion engine, what storage tanks that could be used and how the reforming process could be optimized. 

    The study showed that in order for an ammonia and hydrogen on demand power/fuel system to be competitive, focus must be on how to minimize the external thermal input to the system and using a beneficial storage method for the specific vessel. The system has a cold side in which thermal energy is needed and a hot side in which thermal heat needs to be dissipated, comparing option 1-3 shows that managing these two sides of the system greatly increased the efficiency. 

    The study also shows that having an increased hydrogen mixture above   might be deemed unnecessary since it increases the cracker size needed and amount of ammonia tap off from both the main-stream and combustion-stream. Further investigations are needed on how to optimize the schematical design of the system if the temperature of the mixed-stream is deemed to be too high for the engine, this heat could then be utilized in another part of the cold side of the system.

    Publikationen är tillgänglig i fulltext från 2025-05-25 13:00
  • 9. Enestam, Sonja
    et al.
    Mäkelä, Kari
    Backman, Rainer
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik, Energiteknik och termisk processkemi.
    Hupa, Miko
    Occurrence of Zinc and Lead in Aerosols and Deposits in the Fluidized-Bed Combustion of Recovered Waste Wood. Part 2: Thermodynamic Considerations2011Ingår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 25, nr 4, s. 1970-1977Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In the present work, which is the second part in a series of two, multi-phase, multi-component equilibrium calculations were used to study the chemistry and deposition behavior of lead and zinc in the combustion of recovered waste wood (RWW). Particular attention was paid to the deposition behavior in different parts of the boiler under varying flue gas and material temperature conditions. In addition, the influence of fuel composition was considered by studying three different fuel compositions. The results from the calculations were compared to experimental results from two measurement campaigns, whose goal was to experimentally determine the distribution and speciation of zinc and lead compounds in aerosol particles and deposits in the fluidized-bed combustion of RWW. The results from the experimental work are presented in part 1 (10.1021/ef101478n) of this work.

  • 10.
    Eriksson, Matias
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Characterization of kiln feed limestone by dynamic heating rate thermogravimetry2016Ingår i: International Journal of Mineral Processing, ISSN 0301-7516, E-ISSN 1879-3525, Vol. 147, s. 31-42Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Quicklime is a product rich in calcium oxide produced in industrial kilns. The process involves thermal decomposition of minerals with high content of calcium carbonate. The kiln feed properties vary with the geological formation from where the mineral is quarried or mined. Characterization of feed properties is necessary to achieve an optimized kiln production. In this work the decomposition of four different types of calcite ore was investigated by comparing conventional constant heating rate and dynamic heating rate thermogravimetric methods. The conclusion of this work is that the conventional method always "overshoots" the calcination temperature when continuously heating during calcination compared to the dynamic rate method that resembles the kiln by holding temperatures constant during the calcination event. This justifies the used of the dynamic rate method. By a correct experimental parameter setup the dynamic rate method can be adapted for individual kilns and feed fractions, giving new additional value to the kiln operator and increasing the high value use of limestone deposits. This new method to characterize calcination properties of kiln feed materials can be utilized in normal kiln operations and when developing new mixes of different quality limestone. The results show differences when comparing the methods and different materials even though CaCO3 is present only as calcite. In addition, the dynamic rate method is faster than the conventional method. Besides quicklime production the method can also be applied in other industries calcining limestone, such as cement clinker production.

  • 11.
    Eriksson, Matias
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Sustainability measures in quicklime and cement clinker production2015Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    This thesis investigates sustainability measures for quicklime and cement clinker production. It is the aim of this thesis to contribute to the effort of creating a more sustainable modus of industrial production.

    The methods used comprises process simulations through multicomponent chemical equilibrium calculations, fuel characterization and raw materials characterization through dynamic rate thermogravimetry.

    The investigated measures relate to alternative fuels, co-combustion, oxygen enrichment, oxyfuel combustion, mineral carbonation and optimizing raw material mixes based on thermal decomposition characteristics.

    The predictive multicomponent chemical equilibrium simulation tool developed has been used to investigate new process designs and combustion concepts. The results show that fuel selection and oxygen enrichment influence energy efficiency, and that oxyfuel combustion and mineral carbonation could allow for considerable emission reductions at low energy penalty, as compared to conventional post-combustion carbon dioxide capture technologies. Dynamic rate thermogravimetry, applied to kiln feed limestone, allows for improved feed analysis with a deeper understanding of how mixing of different feed materials will affect the production processes. The predictive simulation tool has proven to be of practical value when planning and executing production and full scale campaigns, reducing costs related to trial and error.

    The main conclusion of this work is that several measures are available to increase the sustainability of the industry.

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  • 12.
    Eriksson, Matias
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik. Nordkalk AB, Köping, Sverige.
    Carlborg, Markus
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Broström, Markus
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Characterization of ring deposits inside a quicklime producing long rotary kiln2019Ingår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 33, nr 11, s. 11731-11740Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Ring deposits are common problems in rotary kiln operations. The ring is constantly subjected to thermal and mechanical wear counteracting the growth of the ring. If the ring hardens or if the growth of the ring is too rapid the kiln needs to be shut down and the ring removed, reducing the operational time and profitability of the process. In the present study, ring deposits from a limestone fed long rotary kiln producing quicklime was sampled and characterized in detail by SEM-EDS, dynamic rate TG and XRD. This work identifies three hardening mechanisms active in the kiln, an increased densification of the ring deposits near the refractory surface, the formation of calcite and spurrite through carbonation of the ring deposits, and the intrusion of molten fuel ash and product into the refractory, resulting in a strong attachment of the deposit to the refractory surface. The work also concludes that a significant part of the ring deposit has its origin in the fuel ash, contributing to deposit mass and increasing ring growth rate.

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  • 13.
    Eriksson, Matias
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik. The Swedish Mineral Processing Research Association—MinFo, Marieviksgatan 25, Stockholm, Sweden.
    Sandström, Karin
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik. Industrial Doctoral School for Research and Innovation, Umeå University, SE-90187 Umeå, Sweden.
    Carlborg, Markus
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Broström, Markus
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Impact of limestone surface impurities on quicklime product quality2024Ingår i: Minerals, E-ISSN 2075-163X, Vol. 14, nr 3, artikel-id 244Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Quicklime is produced through the thermal processing of limestone in industrial kilns. During quarry operations, fine particulate quarry dust adheres to limestone lump surfaces, increasing the bulk concentration of impurities in limestone products. During thermal processing in a kiln, impurities such as Si, Mg, Al, Fe, and Mn react with Ca, reducing quicklime product quality. Which reactant phases are formed, and the extent to which these result in a reduction in quality, has not been extensively investigated. The present study investigated as-received and manually washed limestone product samples from two operational quarries using elemental compositions and a developed predictive multi-component chemical equilibrium model to obtain global phase diagrams for 1000–1500 °C, corresponding to the high-temperature zone of a lime kiln, identifying phases expected to be formed in quicklime during thermal processing. The results suggest that impurities found on the surface of the lime kiln limestone feed reduce the main quality parameter of the quicklime products, i.e., calcium oxide, CaO (s), content by 0.8–1.5 wt.% for the investigated materials. The results also show that, in addition to the effect of impurities, the quantity of CaO (s) varies greatly with temperature. More impurities result in more variation and a greater need for accurate temperature control of the kiln, where keeping the temperature below approximately 1300 °C, that of Hatrurite formation, is necessary for a product with higher CaO (s).

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  • 14.
    Essalhi, Mohamed
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Tavajohi Hassan Kiadeh, Naser
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    García-Payo, M.C.
    Khayet, M.
    10 - Thermo-osmosis2021Ingår i: Osmosis Engineering / [ed] Nidal Hilal, Ahmad Fauzi Ismail, Mohamed Khayet, Daniel Johnson, Elsevier, 2021, 1, s. 279-312Kapitel i bok, del av antologi (Övrigt vetenskapligt)
    Abstract [en]

    The existence of nonisothermal transport of liquids through a gelatin membrane was first described by Lippmann in 1907, and 5 years later, it was investigated by Aubert in more detail using membranes of gelatin pig’s bladder, parchment paper and viscose. In this phenomenon, there is no liquid/vapor phase transition and it is known as thermo-osmosis (TO) or thermal osmosis (TO). Lippmann also observed TO in air, obviously without prior knowledge of the work of Feddersen and Reynolds. However, at that time the lack of theory on irreversible processes prevented the progress towards understanding this phenomenon.

  • 15.
    Fagerström, Jonathan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Fine particle emissions and slag formation in fixed-bed biomass combustion: aspects of fuel engineering2015Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    There is a consensus worldwide that the share of renewable energy sources should be increased to mitigate climate change. The strive to increase the renewable energy fraction can partly be met by an increased utilization of different biomass feedstocks. Many of the "new" feedstocks puts stress on certain challenges such as air pollution emissions and operation stability of the combustion process. The overall objective was to investigate, evaluate, and explain the effects of fuel design and combustion control - fuel engineering - as primary measures for control of slag formation, deposit formation, and fine particle emissions during biomass combustion in small and medium scale fixed-bed appliances. The work in this thesis can be outlined as having two main focus areas, one more applied regarding fuel engineering measures and one more fundamental regarding the time-resolved release of ash forming elements, with particular focus on potassium.

    The overall conclusion related to the abatement of particle emissions and slag formation, is that the release of fine particle and deposit forming matter can be controlled simultaneously as the slag formation during fixed-bed biomass combustion. The methodology is in this perspective denoted “fuel engineering” and is based on a combined approach including both fuel design and process control measures. The studies on time-resolved potassium release showed that a Macro-TG reactor with single pellet experiments was a valuable tool for studying ash transformation along the fuel conversion. The combination of dedicated release determinations based on accurate mass balance considerations and ICP analysis, with phase composition characterization by XRD, is important for the understanding of potassium release in general and time-resolved data in particular. For wood, the results presented in this work supports the potassium release mechanism from "char-K" but questions the previously suggested release mechanism from decomposition of K-carbonates. For straw, the present data support the idea that the major part of the potassium release is attributed to volatilization of KCl. To further explore the detailed mechanisms, the novel approach developed and applied in this work should be complemented with other experimental and analytical techniques.

    The research in this thesis has explored some of the challenges related to the combined phenomena of fuel conversion and ash transformation during thermochemical conversion of biomass, and has contributed with novel methods and approaches that have gained new knowledge to be used for the development of more effective bioenergy systems.

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  • 16.
    Fagerström, Jonathan
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Nyström, Robin
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Broström, Markus
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Dan, Boström
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Boman, Christoffer
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Fuel conversion of large samples in a thermogravimetric analyzer set-up: method description and applications2011Konferensbidrag (Refereegranskat)
  • 17. Fatehi, Hesameddin
    et al.
    Qu, Zhechao
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Schmidt, Florian M.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Bai, Xue-Song
    Effect of Volatile Reactions on the Thermochemical Conversion of Biomass Particles2017Ingår i: 8th International Conference on Applied Energy (ICAE2016) / [ed] Jinyue Yan, Fengchun Sun, SK Chou, Umberto Desideri, Hailong Li, Pietro Campana, Rui Xiong, Elsevier, 2017, Vol. 105, s. 4648-4654Konferensbidrag (Refereegranskat)
    Abstract [en]

    A numerical and experimental study on the conversion of a biomass particle is carried out to quantify the effect of homogeneous volatile combustion on the biomass pyrolysis. The numerical domain consists of a particle and its surrounding and the model considers detailed chemical kinetic mechanism for reaction of pyrolysis products. A detailed pyrolysis model is employed which provides the composition of pyrolysis products. The effect of gas phase reaction on the conversion time and temperature of the particle is analyzed and it was shown that the gas phase reactions results in shorter pyrolysis time. H2O mole fraction and temperature above a biomass pellet from wheat straw (WS) and stem wood (SW) were experimentally measured using tunable diode laser absorption spectroscopy (TDLAS) while recording the particle mass loss. The TDLAS data were used to validate the numerical model developed for biomass conversion. The results showed that by considering the gas phase reactions a good agreement between the measurement and the model prediction for mass loss and temperature can be achieved. For H2O mole fraction on top of the particle, on the other hand, some discrepancy between the model prediction and the experimental data was observed. Nevertheless, the difference in H2O mole fraction would be much larger by neglecting the gas phase reaction at the particle boundary.

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  • 18. Fatehi, Hesameddin
    et al.
    Schmidt, Florian M.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Bai, Xue-Song
    Gas phase combustion in the vicinity of a biomass particle during devolatilization: model development and experimental verification2018Ingår i: Combustion and Flame, ISSN 0010-2180, E-ISSN 1556-2921, Vol. 196, s. 351-363Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A numerical and experimental study on the devolatilization of a large biomass particle is carried out to quantify the effect of homogeneous volatile combustion on the conversion of the particle and on the temperature and species distribution at the particle vicinity. A global chemical kinetic mechanism and a detailed reaction mechanism are considered in a one dimensional numerical model that takes into account preferential diffusivity and a detailed composition of tar species. An adaptive moving mesh is employed to capture the changes in the domain due to particle shrinkage. The effect of gas phase reactions on pyrolysis time, temperature and species distribution close to the particle is studied and compared to experiments. Online in situ measurements of average H2O mole fraction and gas temperature above a softwood pellet are conducted in a reactor using tunable diode laser absorption spectroscopy (TDLAS) while recording the particle mass loss. The results show that the volatile combustion plays an important role in the prediction of biomass conversion during the devolatilization stage. It is shown that the global reaction mechanism predicts a thin flame front in the vicinity of the particle deviating from the measured temperature and H2O distribution over different heights above the particle. A better agreement between numerical and experimental results is obtained using the detailed reaction mechanism, which predicts a wider reaction zone.

  • 19.
    Gao, Qiuju
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Edo, Mar
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Larsson, Sylvia H.
    Collina, Elena
    Rudolfsson, Magnus
    Gallina, Marta
    Oluwoye, Ibukun
    Altarawneh, Mohammednoor
    Dlugogorski, Bogdan Z.
    Jansson, Stina
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Formation of PCDDs and PCDFs in the torrefaction of biomass with different chemical composition2017Ingår i: Journal of Analytical and Applied Pyrolysis, ISSN 0165-2370, E-ISSN 1873-250X, Vol. 123, s. 126-133Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Torrefaction is a thermal pre-treatment technology used to refine biomass, mainly for energy production purposes. However, there is currently a lack of information on the potential formation of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) in the torrefaction process. In this study, torrefaction was conducted using five different types of feedstock: stemwood, bark, wood from a discarded telephone pole, cassava stems and particle board. The feedstock as well as the torrefied biomass (chars) and the volatiles (non-condensable and condensable) generated during torrefaction were analyzed for PCDDs and PCDFs. PCDD concentrations in the torrefaction products were about 2-5 fold of those in the feedstocks. Torrefaction of particle board resulted in extensive formation of PCDDs (7200 ng kg(-1)) compared to the other four feedstocks (13-27 ng kg(-1)). Examination of the homologue profiles suggested that the observed PCDDs in the torrefaction products partly originated from new formation and partly physical transformation from volatilization and re-condensation of PCDDs present in the feedstock. Dechlorination of highly chlorinated compounds (HpCDD and OCDD) in the feedstock to form less chlorinated PCDDs was also observed. Compared to PCDDs, the net formation of PCDFs in the torrefaction process was low, except for the telephone pole sample, for which a dramatic increase (44-fold) of PCDFs was observed. PCDDs and PCDFs were mainly retained in the chars, accounting for 76-96% and 39-74% of the total concentration, respectively. It was also found that the highly chlorinated congeners tended to be retained in the chars, whereas the less chlorinated ones were predominantly volatilized into the gas phase.

  • 20. Gavilà, Llorenç
    et al.
    Constantí, Magda
    Medina, Francisco
    Pezoa-Conte, Ricardo
    Anugwom, Ikenna
    Mikkola, Jyri-Pekka
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Lactic acid production from renewable feedstock: fractionation, hydrolysis, and fermentation2018Ingår i: Advanced Sustainable Systems, ISSN 2366-7486, Vol. 2, nr 3, artikel-id 1700185Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this paper, an integrated fractionation with a switchable ionic liquid (SIL), pulp hydrolysis, and lactic acid fermentation is carried out. For this, SO2-swithced SIL is used for fractionation of sugar cane (Saccharum officinarum) bagasse and giant cane (Arundo donax, AD). SIL is able to extract ≈2/3 of lignin when relatively large wood chips (≈4 mm) are used without any mechanical agitation and just 1 h of treatment time for AD. Furthermore, SIL reuse is successfully demonstrated for four runs. Subsequently, the produced pulps are hydrolyzed within 15 min in a microwave reactor, producing a glucose rich hydrolysates. Finally, these hydrolysates are used as a carbohydrate source for Lactobacillus delbrueckii fermentation, which selectively transform all glucose present into optically pure D-lactic acid. Hence, the whole chain for lactic acid production from biomass is successfully demonstrated.

  • 21.
    Golets, Mikhail
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Heterogeneously Catalyzed Valorization of Monoterpenes to High Value-Added Chemicals2014Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    A potential industrial process is profitable only if it is successfully implemented by the continuously developing chemical industry. Throughout last decades heterogeneous catalysis has opened doors to the creation of various know-how products which previously were considered unfeasible. Moreover, the use of heterogeneous catalysts allows improving existing processes to shift towards more ecological and cost efficient practices. In particular, polymer or fuel compounds could be eco-friendly produced from wood extractives, as an alternative to the conventional oil resources. This goal becomes even more attractive in light of the upcoming peak-oil.

    In the Nordic pulping industry turpentine is widely available as a tonnage by-product. Despite its interesting properties and promising application possibilities this fraction is commonly burned in the recovery boilers for energy. Although the chemical composition of turpentine depends strongly on the specific pulping process, α-pinene is the predominant compound and as such most studied. The general message of this thesis is the successful implementation of the heterogeneous catalysts in one-pot value-added upgrading of crude turpentine and specific terpenes, particularly α-pinene. Concepts allowing the production of fragrances, resins, plastics and pharmaceutical compounds are presented in the current study. Both commercial (Amberlyst 70) and self-prepared (Me/Al-SBA-15 or TiO2) catalysts were studied in several reactions including: acetoxylation, isomerization, dehydroisomerisation and oxidation. Both commercially purified α-pinene and crude thermo-mechanical turpentine were used as raw materials in the catalytic one-pot synthesis of value-added compounds.

    The experiments were performed in both batch and continuous reactor systems depending on the studied reaction. Successful results were obtained in case of several reactions. As an example, upon acetoxylation of α-pinene valuable fragrances – α-terpinyl and bornyl acetates – were produced with yields of 35 and 40 wt-%, respectively. Furthermore, in the dehydroisomerisation reaction of α-pinene, a yield of around 80 wt-% of an important fragrance, solvent and plastics precursor, ρ-cymene, was obtained. In the last case, thermo-mechanical turpentine was also successfully utilized. Still, some α-pinene oxidation tests leading to α-pinene oxide and verbenone fragrances were also carried out. Upon this study, further oxidation of ρ-cymene lead to the formation of ρ-methyl-acetophenone, a product essential for perfumery, pharmaceutical and pesticide industry as well as a potent polymer precursor. In addition, isomerization reactions were performed. Additionally, the catalytic materials were thoroughly characterized and analyzed.

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    Heterogeneously Catalyzed Valorization of Monoterpenes to High Value-Added Chemicals
  • 22.
    Golets, Mikhail
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Samikannu, Ajaikumar
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Blomberg, D.
    Processum Biorefinery Initiative AB, Örnsköldsvik, Sweden.
    Grundberg, H.
    Aditya Birla Domsjö Fabriker AB, Örnsköldsvik, Sweden.
    Wärnå, J.
    Laboratory of Industrial Chemistry and Reaction Engineering, Process Chemistry Centre, Åbo Akademi University, Åbo-Turku, Finland.
    Salmi, T.
    Laboratory of Industrial Chemistry and Reaction Engineering, Process Chemistry Centre, Åbo Akademi University, Åbo-Turku, Finland.
    Mikkola, Jyri-Pekka
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen. Laboratory of Industrial Chemistry and Reaction Engineering, Process Chemistry Centre, Åbo Akademi University, Åbo-Turku, Finland.
    Liquid phase acetoxylation of α-pinene2012Ingår i: NWBC 2012: the 4th Nordic Wood Biorefinery Conference, VTT , 2012, s. 339-341Konferensbidrag (Refereegranskat)
    Abstract [en]

    Chemical pulping and bio-refining results in many fractions such as. tall oil and turpentine that contain substantial amounts of α-pinene and other terpenes. Today these fractions are usually burned in the recovery boilers. However, the northern forest industry, primarily utilizing the boreal forests, faces serious challenges from developing markets (South America, Asia), because of lower cost of raw material resources and labor. At the same time, there is a growing concern about emissions of greenhouse gases and security of supply connected to the use of fossil oil for transportation and as a feedstock for the chemical industry. The mentioned fact renders the substitution of petrochemical-related raw materials an important field of research.

    The flavor and fragrance industry is one of the main users of terpene esters. From those esters, α-terpinyl and bornyl acetates are produced from α-pinene and commonly used for bath products and perfumes. Due to the imperfection of conventional two-stage production method of the mentioned esters, which lays in the equipment corrosion, environmental pollution, large load and nonrecyclability of a catalyst, the novel one-stage catalytic process is always of high priority.

    The possibility of α-pinene liquid phase catalytic acetoxylation is introduced in the present study. The complex product distribution and reaction network analysis, influent reaction and catalytic factors optimization, combined with the reaction kinetic modeling were the main aims of research. The ion-exchange resin catalyst Amberlyst 70 was characterized as the catalyst used in the studied reaction and compared with the solvent-catalyzed mode. Valuable combinations of acetates were obtained for both studied modes. A wide range of process factors were studied in the batch (Parr) reactor used. The mentioned type of reactor is suitable for the consequent industrial operations scale-up calculations.

  • 23.
    Haglund, Peter
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Spinnel, Erik
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    A modular approach to pressurized liquid extraction with in-cell clean-up2010Ingår i: LC GC Europe, ISSN 1471-6577, Vol. 23, nr 6, s. 292-301Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A new concept for the extraction of solid samples has been developed. The popular pressurized liquid extraction (PLE) technique has been modified so that the extraction cell can be divided, which greatly increases the flexibility and versatility of this technique. The system uses simple adaptors to couple commercially available extraction cells, which may be loaded with either sample or adsorbent(s). These segmented extraction cells make it possible to selectively retain analytes or matrix to achieve simultaneous extraction and clean-up or fractionation. The ultimate aim is to perform simultaneous extraction and clean-up and obtain a purified extract that is ready for instrumental analysis, all in line with current trends in analytical chemistry to automate and streamline the analytical procedures to reduce the analysis costs, solvent consumption, manual labour and increase the quality of analysis. Selected modes of operations are presented and a few recent environmental applications of modular PLE are reviewed.

  • 24.
    Haglund, Peter
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Spinnel, Erik
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    A modular approach to pressurized liquid extraction with in-cell clean-up2010Ingår i: LCGC Asia Pacific, ISSN 1754-2715, Vol. 13, nr 2, s. 6-12Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A new concept for the extraction of solid samples has been developed. The popular pressurized liquid extraction (PLE) technique has been modified so that the extraction cell can be divided, which greatly increases the flexibility and versatility of this technique. The system uses simple adaptors to couple commercially available extraction cells, which may be loaded with either sample or adsorbent(s). These segmented extraction cells make it possible to selectively retain analytes or matrix to achieve simultaneous extraction and clean-up or fractionation. The ultimate aim is to perform simultaneous extraction and clean-up and obtain a purified extract that is ready for instrumental analysis, all in line with current trends in analytical chemistry to automate and streamline the analytical procedures to reduce the analysis costs, solvent consumption, manual labour and increase the quality of analysis. Selected modes of operations are presented and a few recent environmental applications of modular PLE are reviewed.

  • 25.
    Hagman, Henrik
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik. Perstorp Specialty Chemicals AB.
    Co-firing animal waste, sludge, residue wood, peat and forest fuels in a 50MWth CFB boiler: ash transformation, availability and process improvements2014Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [sv]

    Den direkta rörliga kostnaden för värme-och elproduktion baserad på fast biobränsle är ungefär 3-5 gånger lägre än kostnaden för fossiloljebaserad produktion. Avfallsklassade fasta biobränslen är vidare oftast betydligt billigare än fasta biobränslen som inte är klassade som avfall. Införandet av de avfallsklassade bränslena; reningsslam, rivningsvirke, och animaliskt avfall i en 50MWth cirkulerande fluidiserad bädd (CFB) -panna, ledde till kraftig beläggningstillväxt i överhettare och ackumulering av aska i ekonomisers, samt haveri av panntuber och centrumrör i cyklonerna, som tvingade fram frekventa pannstopp. Detta ökade i sin tur användningen aveldningsolja (fossilt bränsle) i reservkrafts-pannor vilket resulterade i ett större CO2 utsläpp och en högre kostnad för energiomvandlingen på siten. Detta arbete syftar till att öka den allmänna mekanistiska förståelsen av förbränningssystem som använder komplexa bränslen, och omfattar; haveri- och underhållsstatistik, elementarsammansättningsanalys av aska, beläggningar och bränslefraktioner, rökgasens sammansättning, kemisk specificering av askor och beläggningar, ett försök att beskriva de övergripande askomvandlingsreaktionerna, samt en massbalans för förbränningsprocessen. Svepelektronmikroskop (SEM) utrustat med energidispersiv röntgenspektroskopi (EDS) användes för att analysera den elementära sammansättningen av aska och beläggningar. SEM-EDS-resultaten användes tillsammans med pulverröntgendiffraktionsanalys (XRD), termodynamiska fasdata, och jämviktsberäkningar i ett försök att kvantifiera de kristallina faserna och de övergripande askomvandlingsreaktionerna i processen. Baserat på resultaten rörande askomvandling och haveristatistik, har det varit möjligt att identifiera generiska nyckelparametrar gällande panndesign och processparametrar, som möjliggjort stora förbättringar av CFB pannans tillgänglighet, en lägre totalkostnad för energiomvandlingen på siten samt ett minskat CO2-utsläpp.

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    Co-firing animal waste, sludge, residue wood, peat and forest fuels in a 50MWth CFB boiler
  • 26.
    Hagman, Henrik
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Co-firing complex biomass in a CFB boiler: ash transformation, corrosion control and materials selection2018Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    The effects of greenhouse gas net emissions on global warming, stricter legislation on waste handling, and the pursuit of ever cheaper heat- and power production are all important factors driving the introduction of complex fuels in incineration plants. However - without fundamental knowledge regarding ash transformation, corrosion control, and materials selection – this introduction of potentially economically and environmentally beneficial fuels, might instead cause economic loss and environmentally adverse effects.

    The present work is a contribution to the transition from today's CO2 net generating energy conversion system, to a more environmentally friendly and cost-efficient one. This is done using scientific methods to generate knowledge concerning mechanisms of ash transformation, corrosion control, and materials selection, in a co-fired industrial scale circulating fluidized bed (CFB) boiler, using a novel and biomass-based fuel mix, rich in Na, K, Cl, N, S, P, Ca and Si. Fuel fractions, ashes, flue gas, deposits, and construction material samples have been collected and analyzed using various techniques, including scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), and X-ray Diffraction (XRD). The experimental results have been evaluated and interpreted using chemical equilibrium calculations.

    The results of this work include:

    1) An analysis of; the failure and preventive maintenance statistics of the industrial scale CFB boiler at hand; the elemental composition of boiler ashes and deposits, the flue gas composition and elemental composition of a multitude of fuel fractions; correlations between boiler design, operational parameters, elemental composition of deposits and boiler availability; a boiler elemental mass balance revealing details regarding deposit buildup mechanisms; properties of the fly ash relevant to flue gas filter design; and findings regarding the nitrogen chemistry of the novel and nitrogen-rich fuel mix.

    2) Speciation and description of the overall ash transformation and fireside alloy interaction, enabling the implementation of on-line corrosion control which significantly inhibits superheater and dew-point corrosion in the boiler; and, an equation describing the sulfation potential of the fuel mix, as a result of the direct and indirect interactions between all major ash-forming elements.

    3) A literature review relevant for the co-fired CFB cyclone vortex finder alloy selection and corrosion at 880 °C; An alloy selection study including long term exposures of several commercially available alloys identifying materials that are more than twice as cost-efficient as the often used alloy 253MA; a suggestion of novel methods for both systematic comparison of heavily degraded alloys, and for alloy service-life estimations; a detailed analysis of heavily degraded alloys 310S, 800H/HT and 600, identifying the driving corrosion mechanisms of the VF alloy degradation, including aspects of how the alloy internal mass transport and fireside surface interaction develops over time.

    The knowledge gained during this project has been used in the improvement work of the Perstorp 50 MWth CFB boiler, improving the boiler availability with 7 %, reducing the overall energy conversion costs with around 1.7 MEUR/year.

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  • 27.
    Hermassi, Mehrez
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik. Chemical Engineering Department, East Barcelona Engineering School, Barcelona TECHUPC, (Campus Diagonal-Besos), Sant Adria de Besos, Spain.
    Granados, M.
    Valderrama, C.
    Ayora, C.
    Cortina, J. L.
    Recovery of Rare Earth Elements from acidic mine waters by integration of a selective chelating ion-exchanger and a solvent impregnated resin2021Ingår i: Journal of Environmental Chemical Engineering, E-ISSN 2213-3437, Vol. 9, nr 5, artikel-id 105906Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A polymeric ion-exchange resin, incorporating methyl-amino-phosphonic (TP260) functionalities, and a solvent impregnated resin (SIR) incorporating tri-methylpentylphosphinic acid (TP272), were evaluated for the selective separation of Rare Earth Elements (REE) from Transition (TE), post -Transition (PTE), and Alkaline Earth (AE) Elements in acidic mine waters (AMW). The influence of the functional groups nature and the acidity dependence were studied and their effects on efficiencies for REE removal and separation from TE/PTE were analysed Both resins provided good separation factors of REE from TE/PTE by acidity control of the treated effluent once Fe (III), the major component in AMW, had been removed by precipitation. The TP272 resin, containing trimethylpentylphosphinic acid (Cyanex 272) onto the polymeric network, showed higher affinity towards Heavy REE (HRRE) than for Light REE (LRRE) by acidity control (pH > 4). Higher pre-concentration factors were achieved for TP272 impregnated resin (e.g., 20-30) in comparison with the TP260 phosphonic resin (2-5), as the pH extraction window is in the moderate pH region (1-5). The integration in series of both resins could be used to separate and recover HREE and LREE from TE/PTE from AMW generated concentrates could be used to recover REE as secondary resources for the clean energy technology industry.

  • 28.
    Holmgren, Per
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Strandberg, Anna
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Wagner, David R.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Molinder, Roger
    Energitekniskt Centrum, Piteå.
    Wiinikka, Henrik
    Energitekniskt Centrum, Piteå.
    Umeki, Kentaro
    Luleå Technical University.
    Broström, Markus
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Size, Shape and Density Changes of Biomass Particles during Devolatilization in a Drop Tube Furnace2014Ingår i: Impacts of Fuel Quality on Power Production October 26 –31, 2014, Snowbird, Utah, USA, 2014Konferensbidrag (Övrigt vetenskapligt)
  • 29. Horacek, J.
    et al.
    St'avova, Gabriela
    Hora, Lukas
    Mikkola, Jyri-Pekka
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen. Åbo Akad Univ, Proc Chem Ctr, Ind Chem & React Engn, FIN-20500 Turku, Finland.
    Kubicka, David
    Lignin transformations to chemicals2013Ingår i: Proceedings of the 1st INTERNATIONAL CONFERENCE ON CHEMICAL TECHNOLOGY / [ed] Kalenda, P., Lubojacky, J., Czech Chemical Society , 2013, s. 382-388Konferensbidrag (Refereegranskat)
    Abstract [en]

    Sodium lignosulfonate was decomposed at 320 degrees C and 130 bar over various catalysts. Zeolites Beta modified with 0.5 % of Pt showed important effect of Al content in the support on product yields. Alumina-supported NiO was also found as active in lignosulfonate decomposition to guaiacol: Moreover, the contact time of substrate with the active centers was identified as the key reaction factor in lignosulfonate decomposition. Model compounds of lignin decomposition were hydrodeoxygenated at 180 degrees C and 5 MPa over Pt modified zeolites Beta. Dealuminated zeolite was found as more active in phenol conversion than zeolite with similar Si/Al ratio obtained by direct synthesis. Reactivity of cresols increased in order m>o>p for catalyst with higher Si/Al ratio, decrease of Al content resulted in lower reactivity of cresols and change of reactivity order of isomers to o>m>p.

  • 30.
    Hägglund, Fredrik
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Grön ammoniak i Norra Sverige: Konceptstudie kring förutsättningar för grön ammoniakproduktion i Norra Sverige2022Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Europeiska Unionen presenterade den 8 juni 2020 sin vätgasstrategi i syfte för att minska koldioxidutsläppen. Det unionen vill uppnå med sin vätgasstrategi är att uttnytja konceptet Power-to-X där elektricitet omvandlas till energi. Om elektricitetkällan kommer från förnyelsebar energi kommer grön vätgas produceras. Problemet med vätgas idag är lagring, transport och hanteringstrukturen för ämnet men vätgas kan lagras i flertal applikationer. En av de mest lovande lagringsalternativen är ammoniak som bildas när vätgas med kvävgas reagerar med varandra via ammoniaksyntes. Eftersom vätgasproduktionen idag använder fossila bränslen kommer även dess applikation göra det, men med grön vätgas kommer dess applikation även att bli grön. Idag står ammoniakproduktion för 2 % av fossilbränsleanvändning globalt och frigör mer än 400 miljoner ton CO2 årligen. Dessa utsläpp skulle försvinna om produktionen av ammoniak gjordes med Power-to-X konceptet.

    Syftet med detta examensarbete är att undersöka förutsättningarna ur ett ekonomiskt, tekniskt och säkerhetsmässigt hållbart Power-to-X koncept i form av en Grön Ammoniakanläggning i Norra Sverige. Det innebär att processer för en ammoniakproduktion skall analyseras ur ett teknisk synvinkel där fokus på funktion mot grön ammoniak är i fokus. Den ekonomiska synvinkeln innebär vad kapitalkostnaden (CAPEX) blir för anläggningen samt driftkostnaden (OPEX) som processen får.

    Arbetet innehåller först en analys av de processer som krävs för att kunna producera ammoniak. Därefter en analys över möjliga tekniker för dessa processer, hur väl de fungerar mot grön ammoniak och vilka antaganden som är i detta arbete. Anläggningen skulle vara storskalig vilket innebär en produktion på 500 ton NH3 $/dag. Det är även antaget en kontinuerlig eltillförsel samt att elnät redan är tillgänglig. Detta gav att vätgasproduktionen gjordes med en PEM-elektrolys, där kvävgas fås från kryogen destillation och ammoniak produceras med HB-processen. Resultatet visades att anläggningens CAPEX och OPEX blev 2 820 MSEK respektive 1 272 MSEK/år. Den dominerande faktorn för kapitalkostnaden var för vätgasproduktion som utgjorde 60 % av CAPEX. Den höga kostnaden för PEM-elektrolys är dels för att utvecklingen av processen inte är fullbordad, där utvecklingen för tekniken skulle kunna ge en stor kostnadsreducering. Det elbehov som anläggningen kräver är 1,6 TWh och och utgör en påverkan på OPEX är 55,4 %. Den process som kräver mest energi är vätgasproduktionen vilket omfattar 94 % av hela anläggningens totala elbehov. En stor anledning till de dyra driftkostnaderna är elpriset. I detta arbete valdes elpriset till ett medelvärde för SE1 i Sverige under en 10 års period. I ett verkligt scenario hade vätgasproduktionen kunnat optimeras för uppnå billigare drift.

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  • 31.
    Håkansson, Katarina
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Nordin, Anders
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Nordwaeger, Martin
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Olofsson, Ingemar
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Svanberg, Martin
    Logistics and Transportation, Chalmers University of Technology.
    Process and system integration aspects of biomass torrefaction2010Ingår i: 18th European Biomass Conference and Exhibition: Proceedings, 2010Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    The pre-treatment method torrefaction has been shown to significantly improve biomass fuel characteristics such as energy density, moisture content, milling energy, feeding and hydrophobic properties. These improvements establish torrefaction as a key process in facilitating an expanding market for biomass raw materials. Most of the previous work has focused on evaluating and optimizing the torrefaction process alone. However, to fully explore the maximum energy/exergy and cost efficiency of biomass torrefaction, the entire fuel supply chain and site specific systems must be considered; including logistics, scale and integration with other processes. The present work in progress aims to develop a model that incorporates optimization of the biomass supply chain and process integration systems together with the torrefaction process in order to avoid sub-optimization.

  • 32.
    Håkansson, Katarina
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Olofsson, Ingemar
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Persson, Kristoffer
    Nordin, Anders
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Torrefaction and Gasification of Hydrolysis Residue2008Ingår i: 16th European Biomass Conference and Exhibition: Proceedings, 2008Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    When producing ethanol from lignocellulosic material using hydrolysis combined with fermentation, a large amount of residue consisting of mainly lignin is generated. A significant amount of energy is retained in this residue which may be utilised as a measure for the process to become economically viable. One possibility is as fuel in a gasification process for synthesis gas production, improving the fuel yield and the overall plant efficiency. Furthermore, the pre-treatment method torrefaction has been shown to significantly improve biomass fuel characteristics such as energy density, moisture content, feeding and hydrophobic properties, as well as significantly facilitate particle size reduction. Therefore, the process chain from hydrolysis residue to synthesis gas was investigated and demonstrated in the present work through bench-scale experiments in a batch torrefaction reactor and a bubbling fluidised bed gasifier. The results from the torrefaction work confirmed the improved fuel characteristics and the effects of process variables were evaluated by factorial designed experiments. The torrefaction residence time was identified as the most influential variable. The results from reactivity tests and gasification experiments indicate that hydrolysis residue and corresponding torrefied residue are suitable for synthesis gas production, with some improved feedstock handling characteristics for the latter.

  • 33.
    Hökfors, Bodil
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Phase chemistry in process models for cement clinker and lime production2014Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    The goal of the thesis is to evaluate if developed phase chemical process models for cement clinker and lime production processes are reliable to use as predictive tools in understanding the changes when introducing sustainability measures.

    The thesis describes the development of process simulation models in the application of sustainability measures as well as the evaluation of these models. The motivation for developing these types of models arises from the need to predict the chemical and the process changes in the production process, the impact on the product quality and the emissions from the flue gas.

    The main chemical reactions involving the major elements (calcium, silicon, aluminium and iron) are relatively well known. As for the minor elements, such as sodium and potassium metals, sulphur, chlorine, phosphorus and other trace elements, their influence on the main reactions and the formation of clinker minerals is not entirely known. When the concentrations of minor and trace elements increase due to the use of alternative materials and fuels, a model that can accurately predict their chemistry is invaluable. For example, the shift towards using less carbon intensive fuels and more biomass fuels often leads to an increased phosphorus concentration in the products.

    One way to commit to sustainable development methods in cement clinker and lime production is to use new combustion technologies, which increase the ability to capture carbon dioxide. Introducing oxy-fuel combustion achieves this, but at the same time, the overall process changes in many other ways. Some of these changes are evaluated by the models in this work.

    In this thesis, a combination of the software programs Aspen Plus™ and ChemApp™ constitutes the simulation model. Thermodynamic data from FACT are evaluated and adjusted to suit the chemistry of cement clinker and lime.

    The resulting model has been verified for one lime and two cement industrial processes.

    Simulated scenarios of co-combustion involving different fuels and different oxy-fuel combustion cases in both cement clinker and lime rotary kiln production are described as well as the influence of greater amounts of phosphorus on the cement clinker quality.

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  • 34.
    Hökfors, Bodil
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik. Cementa AB, Stockholm, Sweden.
    Boström, Dan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Viggh, Erik
    Cementa AB, Malmö, Sweden.
    Backman, Rainer
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    On the phase chemistry of Portland cement clinker2015Ingår i: Advances in Cement Research, ISSN 0951-7197, E-ISSN 1751-7605, Vol. 27, nr 1, s. 50-60Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper describes the formation of a phosphorous belite solid solution and its impact on alite formation. A sub-solidus phase relation for the ternary system silicon dioxide–calcium oxide–phosphorus pentoxide (SiO2–CaO–P2O5) is reported. The ternary system is based on Rietveld refinements of X-ray diffraction patterns from experimental tests. The overall picture is based on known phase diagrams, relevant Rietveld refinements models, stoichiometric relationships as a function of increasing phosphorus pentoxide concentration and vacancy theories for solid solutions of phosphate belites. A tool is developed for predicting the chemistry of the product as well as the chemistry during heating when producing Portland cement clinker. A thermodynamic database for phase chemistry calculations of clinkering reactions has been created and evaluated. Suitable compounds and solution species have been selected from the thermochemical database included in FactSage software. Some solution compositions have been uniquely designed to allow for the proper prediction of the cement clinker chemistry. The calculated results from the developed database for heating raw materials in cement clinker production and cooling of the product are presented in this paper. The calculated results provide a good prediction of the phases and quantities formed during heating and non-equilibrium cooling. The prediction of the amounts of alite, belite and aluminoferrite phases in the product according to the Scheil method is good. The temperature interval for the existence of all of the major phases is relevant. The thermodynamic data for a solution phase of alite with substituting ions of primarily magnesium oxide and phosphorus pentoxide would improve the predictability of the developed database.

  • 35.
    Hökfors, Bodil
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik. Cementa AB, Res & Dev, Heidelberg Cement Grp, Heidelberg, Germany.
    Eriksson, Matias
    Nordkalk Oy Ab, FIN-21600 Pargas, Finland.
    Backman, Rainer
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik. Åbo Akad Univ, Proc Chem Res Grp, Turku, Finland.
    Improved Process Modeling for a Lime Rotary Kiln Using Equilibrium Chemistry2012Ingår i: Journal of engineering technology, ISSN 0747-9964, Vol. 29, nr 1, s. 8-18Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This article describes an improved process model for simulation of the manufacturing process of lime in a rotary kiln. The model simulates ideal behavior of complex chemical systems with an assumed homogenous mixing without time-dependent factors. It is a totally predictive model that excludes the empirical parameters. The model is a chemical phase equilibrium model that calculates the final product in a non-equilibrium mode, according to established methods. The phase chemistry is among the most complex found in the literature for lime manufacturing. The thermodynamic data used in the model is based on 11 components (Ca, Si, Al, Fe, K, S, Cl, C, H, O and N). The fuel has an important role in the lime manufacturing process. Special attention is required since it is fed directly into the process via the burner and can influence the process and final product. In the model, the fuel is defined in order to have it behave in a realistic way, and operational data from a full scale lime plant verify the simulation results. The simulated amounts of gas and solids correlate well with operational data. The predicting chemical composition of the product needs improvement by adding more system components and their related compounds to the thermodynamic database. Simulation results from co-combustion of coal and processed waste based fuel oil that it is a versatile tool for predicting product quality and amount, temperature profiles of the rotary kiln, and exhaust gas composition and amount.

  • 36.
    Hökfors, Bodil
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik. Cementa AB, Stockholm, Sweden.
    Eriksson, Matias
    NorFraKalk, Verdal, Norway.
    Viggh, Erik
    Cementa AB, Malmö, Sweden.
    Modelling the cement process and cement clinker quality2014Ingår i: Advances in Cement Research, ISSN 0951-7197, E-ISSN 1751-7605, Vol. 26, nr 6, s. 311-318Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper presents a recently developed simulation model that can be used as a tool for evaluating sustainable development measures for cement and lime production processes. Examples of such measures are introducing new combustion technologies such as oxy-fuel combustion, using biomass fuel and using alternative materials in the raw material feed. One major issue when introducing process changes is the need to maintain product quality. In some ways, oxygen-enriched air combustion resembles oxy-fuel combustion. The model results were validated and found to be consistent with full-scale operational data for normal running conditions and for a full-scale test with oxygenenriched air. The model shows, for example, that with an additional 1500 m3/h of oxygen, fuel addition at the calciners can increase up to 108% and the raw material feed rate can increase up to 116% for a process with a raw meal feed of 335.5 t/h.

  • 37.
    Hökfors, Bodil
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik. Cementa AB, Stockholm, Sweden.
    Viggh, Erik
    Cementa AB, Malmö, Sweden.
    Eriksson, Matias
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik. NorFraKalk, Verdal, Norway.
    Simulation of oxy-fuel combustion in cement clinker manufacturing2015Ingår i: Advances in Cement Research, ISSN 0951-7197, E-ISSN 1751-7605, Vol. 27, nr 1, s. 42-49Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A thermodynamic process model is used as an evaluation tool. Full oxy-fuel combustion is evaluated for circulation of 20–80% of flue gases to the burn zone of a rotary kiln. The full oxy-fuel combustion simulations exhibit altered temperature profiles for the process. With 60% recirculation of flue gases, the temperature in the burn zone is comparable to the reference temperature, and carbon dioxide concentration in the flue gases increases from 33 to 76%. If water is excluded, carbon dioxide concentration is 90%. The partial oxy-fuel combustion method is evaluated for 20 and 40% recirculation of flue gases from one cyclone string to both calciners. Fuel and oxygen feed to the burning zone and calciners are optimised for the partial oxy-fuel scenario. The lowest specific energy consumption is desired while maximising the amount of carbon dioxide theoretically possible to capture. By introducing partial oxy-fuel combustion with 20% recirculation of flue gases in the carbon dioxide string, total carbon dioxide emissions increases by 4%, with 84% possible to capture. Within the limits of the model, the introduction of full oxy-fuel and partial oxyfuel combustion is possible while maintaining product quality. When simulating partial oxy-fuel combustion, the energy consumption will increase even when no power consumption for the production of oxygen is included.

  • 38.
    Hökfors Wilhelmsson, Bodil
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Viggh, Erik O.
    Cementa AB, Limhamn, Sweden.
    Backman, Rainer
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    A predictive chemistry model for the cement process2008Ingår i: Zement, Kalk, Gips International: ZKG international, ISSN 0949-0205, Vol. 61, nr 7, s. 60-70Artikel i tidskrift (Övrigt vetenskapligt)
    Abstract [en]

    A tool has been developed that enables prediction of the chemistry in cement production with thermodynamic phase equilibrium calculations. Reactions in gas, solid and liquid phases are calculated in the process from preheating tower, including exhaust gas cleaning, through rotary kiln, clinker cooler and ends at the output of clinker. The simulated values are compared to measured or calculated data from a full scale plant. This is a cement plant producing 2000 t clinker per day using both traditional and alternative fuels. The chemistry model shows good agreement especially on material chemistry at various places in the process and on composition of the clinker. A new way to define fuels is used and is straightforward and reliable. In the future work the model has to be improved and more elements are to be added to the thermodynamic database.

  • 39.
    Ilanidis, Dimitrios
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Stagge, Stefan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Alriksson, Björn
    Cavka, Adnan
    Jönsson, Leif J.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Comparison of Efficiency and Cost of Methods for Conditioning of Slurries of Steam-Pretreated Softwood2021Ingår i: Frontiers in Energy Research, E-ISSN 2296-598X, Vol. 9, artikel-id 701980Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Inhibitors formed during pretreatment impair lignocellulose bioconversion by making enzymatic saccharification and microbial fermentation less efficient, but conditioning of slurries and hydrolysates can improve fermentability and sometimes also enzymatic digestibility. Conditioning of pretreated softwood using four industrial reducing agents (sodium sulfite, sodium dithionite, sodium borohydride, and hydrogen) was compared with standard methods, such as overliming and treatment with activated charcoal. A dosage of approx. 1 mM sulfur oxyanion (sulfite or dithionite) per percent water-insoluble solids (WIS) in the slurry was found to result in good fermentability. Treatment of 10–20% WIS slurries with 15 mM sulfur oxyanion under mild reaction conditions (23°C, pH 5.5) resulted in sulfonation of the solid phase and saccharification improvements of 18–24% for dithionite and 13–16% for sulfite. Among the different conditioning methods studied, treatment of slurries with sodium sulfite was superior with respect to cost-efficient improvement of fermentability. Treatments of slurry or pretreatment liquid with 15 mM sulfite or dithionite resulted in 58–76% reduction of the content of formaldehyde. The comparison indicates that conditioning of pretreated biomass using sulfur oxyanions warrants further attention.

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  • 40.
    Ismail, Norafiqah
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Essalhi, Mohamed
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Rahmati, Mahmoud
    Cui, Zhaoliang
    Khayet, Mohamed
    Tavajohi Hassan Kiadeh, Naser
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Experimental and theoretical studies on the formation of pure β-phase polymorphs during fabrication of polyvinylidene fluoride membranes by cyclic carbonate solvents2021Ingår i: Green Chemistry, ISSN 1463-9262, E-ISSN 1463-9270, Vol. 23, nr 5, s. 2130-2147Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The use of highly toxic solvents presents significant risks to both the environment and human health. Therefore, the adoption of green solvents will be crucial for achieving sustainable membrane production. This work reports the use of inexpensive environmentally friendly biobased and biodegradable cyclic carbonate solvents, namely ethylene carbonate (EC), propylene carbonate (PC), and butylene carbonate (BC), to fabricate polyvinylidene fluoride (PVDF) membranes. The solvent dependence of the phase inversion mechanisms, morphology, crystalline structures, and polymorphism of the prepared PVDF membranes were investigated. Polymorph analysis revealed that membrane fabrication in EC or PC yielded exclusively the β-phase product, whereas PVDF membrane fabrication in BC yielded a mixture of α and β phase material. The mechanism of β-phase formation was investigated using molecular dynamics simulation and shown to depend on the extent of hydrogen bonding at the polymer–solvent interface. The PVDF membrane formed in EC exhibited the highest porosity and pure water permeability, and was therefore tested in direct contact membrane distillation (DCMD), exhibiting promising results in terms of permeate flux and salt rejection. These results suggest that large-scale production of piezoelectric PVDF membranes using green solvents should be practically feasible.

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  • 41. Jogi, Ramakrishna
    et al.
    Mäki-Arvela, Päivi
    Virtanen, Pasi
    Kumar, Narendra
    Hemming, Jarl
    Russo, Vincenzo
    Samikannu, Ajaikumar
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Lestander, Torbjörn A.
    Mikkola, Jyri-Pekka
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen. Laboratory of Industrial Chemistry and Reaction Engineering, Johan Gadolin Process Chemistry Centre, Åbo Akademi University, Åbo/Turku, Finland.
    Understanding the formation of phenolic monomers during fractionation of birch wood under supercritical ethanol over iron based catalysts2020Ingår i: Journal of the Energy Institute, ISSN 1743-9671, E-ISSN 1746-0220, Vol. 93, nr 5, s. 2055-2062Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The liquefaction of biomass in ethanol, at the critical point, has high potential due to low temperature and pressure (243 °C, 63 bar) when compared with water (374 °C, 220 bar). The current study deals with the fractionation of birch wood powder which was liquefied under supercritical ethanol over acidic or non-acidic catalysts, 5 wt % Fe-Beta-H-150 and 5 wt % Fe–SiO2, respectively. Based on the results, the reaction mechanism for the formation of lignin degradation products was proposed. The main phenolic product was isoeugenol over 5 wt % Fe-Beta-H-150 while intermediate products, i.e. such as coniferyl, and sinapyl alcohol, 4-propenyl syringol, syringaresinol, as well as syringyldehyde reacted rapidly further. The thermodynamic analysis was performed by Joback approach and using Gibbs-Helmholtz equation supporting the obtained results.

  • 42. Jogi, Ramakrishna
    et al.
    Mäki-Arvela, Päivi
    Virtanen, Pasi
    Kumar, Narendra
    Hemming, Jarl
    Smeds, Annika
    Lestander, Torbjörn A.
    Mikkola, Jyri-Pekka
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen. Industrial Chemistry & Reaction Engineering, Johan Gadolin Process Chemistry Centre, Åbo Akademi University, Åbo-Turku, Finland.
    Biocrude production through hydro‐liquefaction of wood biomass in supercritical ethanol using iron silica and iron Beta zeolite catalysts2019Ingår i: Journal of chemical technology and biotechnology (1986), ISSN 0268-2575, E-ISSN 1097-4660, Vol. 94, nr 11, s. 3736-3744Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    BACKGROUND: In the production of biofuels from lignocellulosic material, biocrude plays a key role. The present work deals with the biocrude production through hydrothermal liquefaction (HTL) of birch wood in supercritical ethanol over 5 wt. % Fe‐H‐Beta‐150 (SiO2 to Al2O3 ratio of 150) or 5 wt. % Fe‐SiO2 catalyst.

    RESULTS: The liquid and solid products were characterized with various analytical techniques such as GC‐MS, GC‐FID, SEC, ICP‐MS, p‐XRD, SEM, and solid‐state 13C MAS NMR respectively. The results revealed that 5 wt. % Fe‐H‐Beta‐150, a strongly Brønsted acidic catalyst, enhanced the biocrude formation when compared with a non‐acidic 5 wt. % Fe‐SiO2 catalyst. Hemicellulose and lignin degradation occurred resulting in formation of mainly sugars, acids‐esters and phenolic compounds in liquid phase. The gaseous atmosphere of hydrogen also enhanced the degradation of biomass. The biocrude yield from birch was 25 wt. % over 5 wt. % Fe‐H‐Beta‐150. The Brønsted acidic catalyst gave higher dissolution efficiency and its clear catalytic effect was observed in comparison to non‐acidic 5 wt. % Fe‐SiO2. The degradation level of lignin in presence of 5 wt. % Fe‐H‐Beta‐150 was high 68 wt. % aromatic products were formed, while only 38 wt. % was obtained with 5 wt. % Fe‐SiO2.

    CONCLUSIONS: Hydrogen atmosphere enhances the fractionation of birch wood when compared to argon atmosphere. 5 wt. % Fe‐H‐Beta‐150 catalyst enhanced very strongly the degradation of hemicellulose and lignin in biomass to sugars and acid‐esters as well as phenolic compounds, respectively compared to the non‐acidic 5 wt. % Fe‐SiO2 catalyst.

  • 43.
    Khokarale, Santosh G.
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Bui, Thai Q.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Mikkola, Jyri-Pekka
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen. Industrial Chemistry and Reaction Engineering, Department of Chemical Engineering, Johan Gadolin Process Chemistry Centre, Åbo Akademi University, Finland.
    One-Pot, Metal-Free Synthesis of Dimethyl Carbonate from CO2 at Room Temperature2020Ingår i: Sustainable Chemistry, E-ISSN 2673-4079, Vol. 1, nr 3, s. 17s. 298-314Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Herein, we report on the metal-free, one-pot synthesis of industrially important dimethyl carbonate (DMC) from molecular CO2 under ambient conditions. In this process, initially the CO2 was chemisorbed through the formation of a switchable ionic liquid (SIL), [DBUH] [CH3CO3], by the interaction of CO2 with an equivalent mixture of organic superbase 1,8-diazabicyclo-[5.4.0]-undec-7-ene (DBU) and methanol. The obtained SIL further reacted with methyl iodide (CH3I) to form DMC. The synthesis was carried out in both dimethyl sulfoxide (DMSO) and methanol. Methanol is preferred, as it not only served as a reagent and solvent in CO2 capture and DMC synthesis, but it also assisted in controlling the side reactions between chemical species such as CH3I and [DBUH]+ cation and increased the yield of DMC. Hence, the use of methanol avoided the loss of captured CO2 and favored the formation of DMC with high selectivity. Under the applied reaction conditions, 89% of the captured CO2 was converted to DMC. DBU was obtained, achieving 86% recovery of its salts formed during the synthesis. Most importantly, in this report we describe a simple and renewable solvent-based process for a metal-free approach to DMC synthesis under industrially feasible reaction conditions.

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  • 44.
    Khokarale, Santosh G.
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Mikkola, Jyri-Pekka
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen. Industrial Chemistry & Reaction Engineering, Department of Chemical Engineering, Johan Gadolin Process Chemistry Centre, Åbo Akademi University, FI-20500 Åbo - Turku, Finland.
    Metal free synthesis of ethylene and propylene carbonate from alkylene halohydrin and CO2 at room temperature2019Ingår i: RSC Advances, E-ISSN 2046-2069, Vol. 9, nr 58, s. 34023-34031Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Herein we describe a metal free and one-pot pathway for the synthesis of industrially important cyclic carbonates such as ethylene carbonate (EC) and propylene carbonates (PC) from molecular CO2 under mild reaction conditions. In the actual synthesis, the alkylene halohydrins such as alkylene chloro- or bromo or iodohydrin and organic superbase, 1,8-diazabicyclo-[5.4.0]-undec-7-ene (DBU) reacted equivalently with CO2 at room temperature. The syntheses of cyclic carbonates were performed in DMSO as a solvent. Both 1,2 and 1,3 halohydrin precursors were converted into cyclic carbonates except 2-bromo- and iodoethanol, which were reacted equivalently with DBU through n-alkylation and formed corresponding n-alkylated DBU salts instead of forming cyclic carbonates. NMR analysis was used to identify the reaction components in the reaction mixture whereas this technique was also helpful in terms of understanding the reaction mechanism of cyclic carbonate formation. The mechanistic study based on the NMR analysis studies confirmed that prior to the formation of cyclic carbonate, a switchable ionic liquid (SIL) formed in situ from alkylene chlorohydrin, DBU and CO2. As a representative study, the synthesis of cyclic carbonates from 1,2 chlorohydrins was demonstrated where the synthesis was carried out using chlorohydrin as a solvent as well as a reagent. In this case, alkylene chlorohydrin as a solvent not only replaced DMSO in the synthesis but also facilitated an efficient separation of the reaction components from the reaction mixture. The EC or PC, [DBUH][Cl] as well as an excess of the alkylene chlorhydrin were separated from each other following solvent extraction and distillation approaches. In this process, with the applied reaction conditions, >90% yields of EC and PC were achieved. Meanwhile, DBU was recovered from in situ formed [DBUH][Cl] by using NaCl saturated alkaline solution. Most importantly here, we developed a metal free, industrially feasible CO2 capture and utilization approach to obtain EC and PC under mild reaction conditions.

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  • 45.
    Khokarale, Santosh G.
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Shelke, Ganesh
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Mikkola, Jyri-Pekka
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen. Industrial Chemistry & Reaction Engineering, Johan Gadolin Process Chemistry Centre, Department of Chemical Engineering, Åbo Akademi University, Åbo-Turku, Finland.
    Integrated and Metal Free Synthesis of Dimethyl Carbonate and Glycidol from Glycerol Derived 1,3-Dichloro-2-propanol via CO2 Capture2021Ingår i: Clean Technologies, ISSN 2571-8797, Vol. 3, nr 4, s. 685-698s. 685-698Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Dimethyl carbonate (DMC) and glycidol are considered industrially important chemical entities and there is a great benefit if these moieties can be synthesized from biomass-derived feedstocks such as glycerol or its derivatives. In this report, both DMC and glycidol were synthesized in an integrated process from glycerol derived 1,3-dichloro-2-propanol and CO2 through a metal-free reaction approach and at mild reaction conditions. Initially, the chlorinated cyclic carbonate, i.e., 3-chloro-1,2-propylenecarbonate was synthesized using the equivalent interaction of organic superbase 1,8-diazabicyclo [5.4.0] undec-7-ene (DBU) and 1,3-dichloro-2-propanol with CO2 at room temperature. Further, DMC and glycidol were synthesized by the base-catalyzed transesterification of 3-chloro-1,2-propylenecarbonate using DBU in methanol. The synthesis of 3-chloro-1,2-propylenecarbonate was performed in different solvents such as dimethyl sulfoxide (DMSO) and 2-methyltetrahydrofuran (2-Me-THF). In this case, 2-Me-THF further facilitated an easy separation of the product where a 97% recovery of the 3-chloro-1,2-propylenecarbonate was obtained compared to 63% with DMSO. The use of DBU as the base in the transformation of 3-chloro-1,2-propylenecarbonate further facilitates the conversion of the 3-chloro-1,2 propandiol that forms in situ during the transesterification process. Hence, in this synthetic approach, DBU not only eased the CO2 capture and served as a base catalyst in the transesterification process, but it also performed as a reservoir for chloride ions, which further facilitates the synthesis of 3-chloro-1,2-propylenecarbonate and glycidol in the overall process. The separation of the reaction components proceeded through the solvent extraction technique where a 93 and 89% recovery of the DMC and glycidol, respectively, were obtained. The DBU superbase was recovered from its chlorinated salt, [DBUH][Cl], via a neutralization technique. The progress of the reactions as well as the purity of the recovered chemical species was confirmed by means of the NMR analysis technique. Hence, a single base, as well as a renewable solvent comprising an integrated process approach was carried out under mild reaction conditions where CO2 sequestration along with industrially important chemicals such as dimethyl carbonate and glycidol were synthesized.

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  • 46. Kocík, Jaroslav
    et al.
    Samikannu, Ajaikumar
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Bourajoini, Hasna
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Pham, Tung Ngoc
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Mikkola, Jyri-Pekka
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen. Faculty of Science and Engineering, Industrial Chemistry & Reaction Engineering, Johan Gadolin Process Chemistry Centre, Åbo Akademi University, Åbo-Turku, Finland.
    Hájek, Martin
    Čapek, Libor
    Screening of active solid catalysts for esterification of tall oil fatty acids with methanol2017Ingår i: Journal of Cleaner Production, ISSN 0959-6526, E-ISSN 1879-1786, Vol. 155, nr 1, s. 34-38Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The paper is focused on the description of the activity/selectivity of mesoporous silica based materials loaded with various types of active species in the esterification of tall oil free fatty acids. The metals such as aluminium, molybdenum, gallium and zinc, including their combinations were impregnated on the mesoporous silica, which was tested in esterification reaction. All these catalysts preserved its tall oil free fatty conversion in the first and the second catalytic cycles. However, while only insignificant amount of gallium or molybdenum was lost from the solid catalyst into the liquid phases, zinc leached from every studied solid catalyst. In contrast to impregnated gallium on mesoporous silica, which exhibited higher acidity and higher tall oil free fatty acids conversion in the first catalytic cycle, but its value was not preserved in the second catalytic test.

  • 47.
    Konwar, Lakhya Jyoti
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Mäki-Arvela, Päivi
    Mikkola, Jyri-Pekka
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen. Laboratory of Industrial Chemistry and Reaction Engineering, Johan Gadolin Process Chemistry Centre, Åbo Akademi University, Åbo-Turku, Finland.
    SO3H-Containing Functional Carbon Materials: Synthesis, Structure, and Acid Catalysis2019Ingår i: Chemical Reviews, ISSN 0009-2665, E-ISSN 1520-6890, Vol. 119, nr 22, s. 11576-11630Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The “sulfonated carbons” are a new class of metal-free solid protonic acids characterized by their unique carbon structure and Brønsted acidity (−H0 = 8–11) on par to concentrated H2SO4. These carbon materials covalently functionalized with SO3H groups via C–PhSO3H or C–SO3H linkages can act as versatile water-tolerant solid acids. Due to their low production costs, unique surface chemistry, high chemical and thermal stability, as well as tailorable pore structures they are regarded as potential substitutes to liquid H2SO4. Catalysis, in particular, biomass and large molecule catalysis, is one of the important areas in which acidic carbons have demonstrated exceptional activity and selectivity, outperforming traditional solid acid catalysts (cation-exchange resins, sulfated oxides, and acidic zeolites). In this review we address developments in the different types SO3H- and PhSO3H-functionalized acidic carbon materials, their structure, active sites, and surface properties, applications in catalysis, as well as activation and deactivation characteristics covering important literature since 2004. In particular, we aim to provide a systematic discussion on the specific merits and demerits of such materials obtained from different carbon precursors and functionalization methods which directly influence the structure–stability–acidic properties and catalytic performance.

  • 48.
    Konwar, Lakhya Jyoti
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Oliani, Benedetta
    Department of Industrial Engineering, University of Padova, Padova, Italy.
    Samikannu, Ajaikumar
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Canu, Paolo
    Department of Industrial Engineering, University of Padova, Padova, Italy.
    Mikkola, Jyri-Pekka
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen. Laboratory of Industrial Chemistry and Reaction Engineering, Johan Gadolin Process Chemistry Centre, Åbo Akademi University, Turku, Finland.
    Efficient hydrothermal deoxygenation of tall oil fatty acids into n-paraffinic hydrocarbons and alcohols in the presence of aqueous formic acid2022Ingår i: Biomass Conversion and Biorefinery, ISSN 2190-6815, E-ISSN 2190-6823, Vol. 12, nr 1, s. 51-62Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Hydrothermal deoxygenation of tall oil fatty acids (TOFA) was investigated in the presence of aqueous formic acid (0.5–7.5 wt%) as a H2 donor in the presence of subcritical H2O pressure (569–599 K). Pd and Ru nanoparticles supported on carbon (5% Pd/CSigma, 5% Ru/CSigma, 10% Pd/CO850_DP, and 5% Ru/COPcomm_DP) were found to be efficient catalysts for deoxygenation of TOFA. The reaction pathway was mainly influenced by the concentration of formic acid and the catalyst. In case of Pd catalysts, in the presence of 0–2.5 wt% formic acid, decarboxylation was the dominant pathway producing n-paraffinic hydrocarbons with one less carbon atom (heptadecane yield up to 94 wt%), while with 5–7.5% formic acid, a hydrodeoxygenation/hydrogenation mechanism was favored producing C18 deoxygenation products octadecanol and octadecane as the main products (yields up to 70 wt%). In contrast, Ru catalysts produced a mixture of C5-C20 (n-and iso-paraffinic) hydrocarbons via decarboxylation, cracking and isomerization (up to 58 wt% C17 yield and total hydrocarbon yield up to 95 wt%) irrespective of formic acid concentration. Kinetic studies showed that the rates of deoxygenation displayed Arrhenius type behavior with apparent activation energies of 134.44 ± 31.36 kJ/mol and 148.92 ± 3.66 kJ/mol, for the 5% Pd/CSigma and 5% Ru/CSigma catalyst, respectively. Furthermore, the experiments with glycerol tristearate, rapeseed oil, sunflower oil, rapeseed biodiesel, and hydrolyzed rapeseed oil produced identical products confirming the versatility of the aforementioned catalytic systems for deoxygenation of C18 feedstocks.

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  • 49.
    Koroidov, Sergey
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Anderlund, Magnus F
    Styring, Stenbjörn
    Thapper, Anders
    Messinger, Johannes
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    First turnover analysis of water-oxidation catalyzed by Co-oxide nanoparticles2015Ingår i: Energy & Environmental Science, ISSN 1754-5692, E-ISSN 1754-5706, Vol. 8, nr 8, s. 2492-2503Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Co-oxides are promising water oxidation catalysts for artificial photosynthesis devices. Presently, several different proposals exist for how they catalyze O-2 formation from water. Knowledge about this process at molecular detail will be required for their further improvement. Here we present time-resolved O-18-labelling isotope-ratio membrane-inlet mass spectrometry (MIMS) experiments to study the mechanism of water oxidation in Co/methylenediphosphonate (Co/M2P) oxide nanoparticles using [Ru(bpy)(3)](3+) (bpy = 2,2'-bipyridine) as chemical oxidant. We show that O-16-Co/M2P-oxide nanoparticles produce O-16(2) during their first turnover after simultaneous addition of (H2O)-O-18 and [Ru(bpy)(3)](3+), while sequential addition with a delay of 3 s yields oxygen reflecting bulk water O-18-enrichment. This result is interpreted to show that the O-O bond formation in Co/M2P-oxide nanoparticles occurs via intramolecular oxygen coupling between two terminal Co-OHn ligands that are readily exchangeable with bulk water in the resting state of the catalyst. Importantly, our data allow the determination of the number of catalytic sites within this amorphous nanoparticular material, to calculate the TOF per catalytic site and to derive the number of holes needed for the production of the first O-2 molecule per catalytic site. We propose that the mechanism of O-O bond formation during bulk catalysis in amorphous Co-oxides may differ from that taking place at the surface of crystalline materials.

  • 50. Kumar Raul, Prasanta
    et al.
    Mahanta, Abhijit
    Borah, Raju K.
    Bora, Utpal
    Jyoti Thakur, Ashim
    Mikkola, Jyri-Pekka
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen. Industrial Chemistry & Reaction Engineering, Process Chemistry Centre, Åbo Akademi University, Finland.
    Shchukarev, Andrey
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Microwave assisted and in-situ generated palladium nanoparticles catalysed desulfitative synthesis of cross-biphenyls from arylsulfonyl chlorides and phenylboronic acids2021Ingår i: Results in Chemistry, ISSN 2211-7156, Vol. 3, artikel-id 100181Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A microwave assisted reaction protocol for Suzuki–Miyaura cross-coupling has been developed. Substituted arylboronic acids and arylsulfonyl chlorides coupled under microwave irradiation (MWI) to produce cross-biphenyls in high yields under aerobic condition. The principal advantage of this protocol is that formation of cross-biphenyls was achieved within shorter time along with desulfurization of arylsulfonyl chloride. In-situ generated Pd nanoparticles (NPs) act as catalyst in the reaction. Substituents like methyl, halogens, cyano, amino and t-butyl groups in arylboronic acids tolerate the reaction condition. Pd NPs could be reused several times under chosen reaction conditions without losing its activity significantly. The product formation and the role of the catalyst for the cross-coupling reaction has been rationalised with the help of a proposed mechanism. This reaction is one of the examples of In-situ generated Nanoparticles-catalyzed Organic Synthesis Enhancement (i-NOSE) approach. The approach derives its importance in terms of catalyst’s (i) simple preparation method, (ii) stability under the chosen reaction condition, (iii) substrate specificity, (iv) simple filtration to recover the catalyst and (v) easy regeneracy which clearly indicate that the approach could be applicable for various types of catalytic transformations.

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