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  • 1. Abbasalizadeh, Aida
    et al.
    Malfliet, Annelies
    Seetharaman, Seshadri
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Sietsma, Jilt
    Yang, Yongxiang
    Electrochemical Extraction of Rare Earth Metals in Molten Fluorides: Conversion of Rare Earth Oxides into Rare Earth Fluorides Using Fluoride Additives2017Ingår i: JOURNAL OF SUSTAINABLE METALLURGY, ISSN 2199-3823, Vol. 3, nr 3, s. 627-637Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In the present research on rare earth extraction from rare earth oxides (REOs), conversion of rare earth oxides into rare earth fluorides with fluoride fluxes is investigated in order to overcome the problem of low solubility of the rare earth oxides in molten fluoride salts as well as the formation of oxyfluorides in the fluorination process. Based on thermodynamic calculations, a series of experiments were performed for converting the rare earth oxides into rare earth fluorides using AlF3, ZnF2, FeF3, and Na3AlF6 as fluorinating agents in a LiF-Nd2O3 system. The formation of neodymium fluoride as a result of the reactions between these fluxes and neodymium oxide is confirmed. The rare earth fluoride thus formed can subsequently be processed through the electrolysis route in the same reactor, and rare earth metal can be produced as the cathodic deposit. In this concept, the REO dissolution in molten fluorides would become unnecessary due to the complete conversion of the oxide into the fluoride, REF3. The results of XRD and EPMA analysis of the reacted samples indicate that AlF3, ZnF2, and FeF3 can act as strong fluorinating agents for the neodymium oxide giving rise to a complete conversion of neodymium oxide into neodymium fluoride.

  • 2. Abbasalizadeh, Aida
    et al.
    Malfliet, Annelies
    Seetharaman, Seshadri
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Sietsma, Jilt
    Yang, Yongxiang
    Electrochemical Recovery of Rare Earth Elements from Magnets: Conversion of Rare Earth Based Metals into Rare Earth Fluorides in Molten Salts2017Ingår i: Materials transactions, ISSN 1345-9678, E-ISSN 1347-5320, Vol. 58, nr 3, s. 400-405Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In the present work, selective extraction of rare earth (RE) metals from NdFeB magnets is investigated by studying the effects of various fluxes, viz. AlF3, ZnF2, FeF3 and Na3AlF6 in the LiF-NdFeB system. The aim is to convert RE from RE magnet into the fluoride salt melt. The results show the complete selective separation of neodymium (also dysprosium) from the magnet and formation of rare earth fluoride, leaving iron and boron unreacted. The formed rare earth fluoride can subsequently be processed in the same reactor through an electrolysis route so that RE can be deposited as a cathode product. The results of XRD and EPMA analysis of the reacted samples indicate that AlF3, ZnF2 and FeF3 can act as strong fluorinating agents for extraction of rare earth from NdFeB magnet, converting the RE to REF3. The results confirm the feasibility of the rare earth metals recovery from scrap NdFeB magnet as raw material. The fluoride conversion- electrolysis route suggested in the present work enables the extraction of rare earth metals in a single step using the above-mentioned fluxes.

  • 3. Abel, S
    et al.
    Bäbler, Matthäus
    ETH, Inst Chem & Bioengn, Dept Chem & Appl Biosci.
    Arpagaus, C
    Mazzotti, M
    Stadler, J
    Two-fraction and three-fraction continuous simulated moving bed separation of nucleosides2004Ingår i: Journal of Chromatography A, ISSN 0021-9673, E-ISSN 1873-3778, Vol. 1043, nr 2, s. 201-210Artikel i tidskrift (Refereegranskat)
    Abstract [en]

     A new experimental set-up and a new simulated moving bed (SMB) operation are presented in this work. A desktop SMB unit developed as a modification of the commercial AKTA(TM) explorer working platform has been utilized for the separation of different mixtures of nucleosides. Both two fraction and three fraction SMB separations have been carried out, the latter made possible by the adoption of a new SMB configuration and operating mode (three fraction SMB, 3F-SMB, operation). Experiments demonstrate the feasibility of the 3F-SMB operation, and confirm the trends predicted based on considerations about retention of the components to be separated along the unit. 

  • 4.
    Agthe, Michael
    et al.
    Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University.
    Wetterskog, Erik
    Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University.
    Mouzon, Johanne
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Salazar-Alvarez, German
    Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University.
    Bergström, Lennart Magnus
    Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University.
    Dynamic growth modes of ordered arrays and mesocrystals during drop-casting of iron oxide nanocubes2014Ingår i: CrystEngComm, ISSN 1466-8033, E-ISSN 1466-8033, Vol. 16, nr 8, s. 1443-1450Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The growth modes of self-assembled mesocrystals and ordered arrays from dispersions of iron oxide nanocubes with a mean edge length of 9.6 nm during controlled solvent removal have been investigated with a combination of visible light video microscopy, atomic force microscopy and scanning electron microscopy. Mesocrystals with translational and orientational order of sizes up to 10 μm are formed spontaneously during the final, diffusion-controlled, drop-casting stage when the liquid film is very thin and the particle concentration is high. Convection-driven deposition of ordered nanocube arrays at the edge of the drying droplet is a manifestation of the so called coffee-ring effect. Dendritic growth or fingering of rapidly growing arrays of ordered nanocubes could also be observed in a transition regime as the growth front moves from the initial three-phase contact line towards the centre of the original droplet.

  • 5.
    Aguilar, Wilson
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Study of the Synthesis of ZSM-5 from Inexpensive Raw Materials2014Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    ZSM-5 is an aluminosilicate with high silica ratio with suitable properties for catalysis, ion exchange, adsorption and membrane applications. ZSM-5 is usually produced industrially from concentrated systems in which there is formation of an amorphous gel phase. Typical syntheses of ZSM-5 require sources of silicon and aluminium, a mineralizer and an organic molecule as so-called templating agent. The silicon and aluminum sources widely used for the synthesis are pure reagent chemicals and in particular quaternary ammonium compounds like tetrapropyl ammonium hydroxides (TPA-OH), are employed as templating agents. Unfortunately, these compounds are rather expensive. Demand for inexpensive sources of aluminosilicates for the synthesis of ZSM-5 has increased during the last two decades. Natural raw materials such as kaolin clay and diatomaceous earth (diatomite) are two potential inexpensive sources of silica and alumina. Moreover, the molecule n-butylamine (NBA) has been reported as a low-cost templating agent to replace the quaternary ammonium compounds. The aim of this work was to show for the first time that leached metakaolinite or diatomite in combination with sodium hydroxide and n-butylamine could be used as inexpensive raw materials for the synthesis of ZSM-5 without using an additional source of silica. After synthesis optimization, both sources of aluminosilicate were found to behave differently during the course of synthesis and led to slightly different products. The chemical composition of the raw materials and the products were determined using inductively coupled plasma-sector field mass spectrometry (ICP-SFMS). Crystallinity was examined by X-ray diffractometry (XRD), the morphology was studied by extreme-high-resolution scanning electron microscopy (XHR-SEM) and the specific surface area was estimated from nitrogen adsorption data by the BET method. The chemical composition of individual crystals was determined by energy dispersive spectrometry (EDS). Dealumination of the raw materials by acid leaching made it possible to reach appropriate SiO2/Al2O3 ratios and reduced the amount of impurities. The final ZSM-5 products had a SiO2/Al2O3 ratio in the range 20 – 40. The use of leached diatomite allowed reaching higher yield of ZSM-5 crystals within comparable synthesis times. However, low amounts of mordenite were formed, which was related to the high calcium content of diatomite. Another considerable advantage of diatomite over kaolin is that diatomite does not require heat treatment at high temperature to convert the kaolin to reactive metakaolin. Further characterization of the system by XHR-SEM and EDS at low voltage was carried out in order to understand the nucleation and early growth of the ZSM-5 zeolite crystals. The observations with unprecedented detail strongly suggest that nucleation and the succeeding growth occurs on the gel surface. The growth rates in the various crystallographic directions already at an early stage are such that the shape of the growing crystals resembles that of the final crystals. However, as the early growth is interface mediated, the growth rate along the gel particles is high and the gel particles will become partially embedded inside the growing crystals at an early stage. The Si and Al nutrients are probably transported along the solid/liquid interface and possibly through the liquid in the form of nanoparticles detaching from the gel. The organic template was initially contained in the liquid. However, it remains unclear at which stage the template becomes incorporated in the solid material. EDS at low voltage was also used to gain compositional information about the sodium/calcium ion exchanged products and extraneous phases when kaolin and Bolivian montmorillonite clay were used for the synthesis of zeolite A by alkali fusion. In order to evaluate the cation exchange capacity (CEC) of the synthesized zeolite, ICP-SFMS and EDS were compared. The EDS method used in this work resulted in (Na,Ca)/Al ratios in equivalent moles very close to 1.0 as expected and was therefore found more reliable than ICP-SFMS to measure cation exchange capacity for zeolite A. To summarize, the present work shows that it was possible to synthesize well-crystallized ZSM-5 zeolite from inexpensive raw materials such as leached metakaolin or leached diatomite, sodium hydroxide and n-butyl amine. Furthermore, the crystallization mechanism evidenced in this system might be more general and also apply for other concentrated systems, e.g. those using TPA as structure-directing. Finally, this work displays that EDS at low voltage can provide valuable local compositional information in the field of zeolite synthesis.

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  • 6.
    Aguilar, Wilson
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik. Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Cardenas, Edgar
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Hedlund, Jonas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik. Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Mouzon, Johanne
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik. Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Dendritic growth of NBA-ZSM-5Ingår i: Microporous and Mesoporous Materials, ISSN 1387-1811, E-ISSN 1873-3093Artikel i tidskrift (Övrigt vetenskapligt)
    Abstract [en]

    Crystallization of ZSM-5 zeolite from a gel using n-butylamine as structure-directing agent was studied. Extreme high-resolution transmission and scanning electron microscopy showed the presence of dendritic features that are present at the crystal surface during most of the reaction time that become smoother towards completion of the crystallization. In addition, a web that likely stems from the gel, comprised of alumina-rich nanoparticles between the dendrites at the surface of the crystals was also identified. When the gel is not in direct contact with the crystal surface, dendrites and the web are not observed, and the crystals grow faster. Thus, the alumina-rich web retards the crystal growth and cause the formation of dendritic features.

  • 7.
    Aguilar, Wilson
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Garcia, Gustavo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Hedlund, Jonas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Mouzon, Johanne
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Comparison between leached metakaolin and leached diatomaceous earth as raw materials for the synthesis of ZSM-52014Ingår i: SpringerPlus, E-ISSN 2193-1801, Vol. 3, nr 1Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Inexpensive raw materials have been used to prepare ZSM-5 zeolites with SiO2/Al2O3 molar ratios in the range 20 - 40. Kaolin or Bolivian diatomaceous earth was used as aluminosilicate raw materials and sodium hydroxide and n-butylamine were used as mineralizing agents and template. Dealumination of the raw materials by acid leaching made it possible to reach appropriate SiO2/Al2O3 ratios and to reduce the amount of iron and other impurities. After mixing the components and aging, hydrothermal treatment was carried out and the products were recovered The results clearly show for the first time that well-crystallized ZSM-5 can be directly prepared from leached metakaolin or leached diatomaceous earth using sodium hydroxide and n-butylamine as mineralizing agents and template under appropriate synthesis conditions. A longer induction time prior to crystallization was observed for reaction mixtures prepared from leached diatomaceous earth, probably due to slower digestion of the fossilized diatom skeletons as compared with that for microporous leached metakaolin. The use of leached diatomaceous earth allowed higher yield of ZSM-5 crystals within comparable synthesis times. However, low amounts of Mordenite formed, which was related to the high calcium content of diatomaceous earth. Another considerable advantage of diatomaceous earth over kaolin is that diatomaceous earth does not require heat treatment at high temperature for metakaolinization.

  • 8.
    Aguilar-Mamani, Wilson
    et al.
    Department of Chemistry, Faculty of Science and Technology, San Simon University, UMSS, Cochabamba.
    Akhtar, Farid
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Hedlund, Jonas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Mouzon, Johanne
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Solution-mediated growth of NBA-ZSM-5 crystals retarded by gel entrapment2018Ingår i: Journal of Crystal Growth, ISSN 0022-0248, E-ISSN 1873-5002, Vol. 487, s. 57-64Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The synthesis of flat tablet-shaped ZSM-5 crystals from a gel using metakaolin as aluminosilicate source and n-butyl amine as structure directing agent was investigated. The evolution inside the solid phase was characterized by X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, thermogravimetry and mass spectrometry. A kinetic study indicated that the nucleation of the majority crystals occurred concurrently with the formation of the gel upon heating the starting liquid suspension. Microstructural evidences undeniably showed that the gel precipitated on ZSM-5 crystals and mineral impurities originating from kaolin. As a result, crystal growth was retarded by gel entrapment, as indicated by the configuration and morphology of the embedded crystals. The results presented herein are harmonized with a solution-mediated nucleation and growth mechanism. Our observations differ from the autocatalytic model that suggests that the nuclei rest inside the gel until released when the gel is consumed. Our results show instead that it is crystals that formed in an early stage before entrapment inside the gel that rest inside the gel until exposed at the gel surface. These results illustrate the limitation of the classical method used in the field to determine nucleation profiles when the crystals become trapped inside the gel.

  • 9.
    Aguilar-Mamani, Wilson
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik. Department of Chemistry, Faculty of Science and Technology, San Simon University, Cochabamba, Bolivia.
    Hedlund, Jonas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Mouzon, Johanne
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Internal structure of a gel leading to NBA-ZSM-5 single crystals2018Ingår i: Journal of porous materials, ISSN 1380-2224, E-ISSN 1573-4854, Vol. 25, nr 6, s. 1551-1559Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Porous gel structures are formed during the synthesis of the zeolite ZSM-5 due to the reaction between a source of aluminosilicate, sodium hydroxide, water and a structure directing agent, such as e.g. tetrapropylammonium (TPA) or n-butylamine (NBA). In the present work, the formation of the gel in a heterogeneous system leading to the crystallization of NBA-ZSM-5 zeolite from leached metakaolin was studied extensively. The solid and liquid phases obtained after separation were analyzed by inductively coupled plasma sector field mass spectrometry, dynamic light scattering, extreme high resolution-scanning electron microscopy, energy dispersive spectroscopy, high resolution-transmission electron microscopy, X-ray diffraction and nitrogen gas adsorption. The main gel phase formed after hydrothermal treatment exhibited a sponge-like structure resembling those forming in (Na, TPA)-ZSM-5-based systems. For the first time, the walls of the main gel were shown to be inhomogenous and to possess a biphasic internal structure consisting of a mesoporous skeleton of aluminosilicate nanoparticles embedded in a silicate-rich soluble matrix of soft matter. The data presented in this paper is of primary importance to understand the mechanism by which the gel is consumed and contributes to the growth process of the zeolite crystals.

  • 10.
    Ahlawat, Paramvir
    KTH, Skolan för kemivetenskap (CHE).
    Modellering och implementering av simultan dubbel gradient kromatografi2015Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Polypeptides are becoming an important component of the antibiotic therapeutics. The production demand of therapeutic polypeptides is increasing and there is a significant interest in developing more efficient production processes. In pharmaceutical industries, polypeptides are produced as a crude mixture. Reverse phase high performance liquid chromatography (RP HPLC) is used as a typical separation technique to purify the target polypeptide from other impurities. Currently organic modifier gradients are used to elute product peptides separately from impurities. In this work, we add a second, simultaneous counter-ion gradient, in the hope of increasing separation performance and call it double gradient reverse phase chromatography. A general procedure of the model-based optimization of a polypeptide crude mixture purification process was followed to evaluate the effects of the double gradients on industrial chromatographic process. The target polypeptide elution profile was modeled with a bi-Langmuir adsorption equilibrium isotherm. The isotherm parameters of the target polypeptide were estimated by the inverse method. The model parameters of the impurities were regressed from experimental data. The variations of the isotherm parameters with the modifier concentration and counter-ion concentration were taken into account of the adsorption model. After model calibration and validation by comparison with suitable experimental data, Pareto optimization of the process were carried out to analyze the differences between single gradient chromatography and double gradient chromatography. It was observed that the additional linear gradient of counter-ion concentration did not improve the separation process. Conclusively we were able to demonstrate the concept of double gradient reverse phase chromatography within limited time and possible least experimental efforts.

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  • 11.
    Ahmad, Waqar
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Lin, Leteng
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Strand, Michael
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Benzene conversion using a partial combustion approach in a packed bed reactor2022Ingår i: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 239, nr Part C, artikel-id 122251Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This study investigates the partial combustion technique for tar conversion using a modified experimental set up comprising a packed bed reactor with bed-inside probe for air supply. Simulated producer gas (SPG) and benzene were selected as a real producer gas alternative and model tar component respectively. The benzene conversion was investigated under different experimental conditions such as reactor temperature (650–900 °C), packed bed height (0–12 cm), residence time (1.2–1.9 s), air fuel ratio (0.2 and 0.3) and SPG composition. The results showed insignificant effect of temperature over benzene conversion while air fuel ratio of 0.3 caused high benzene conversion than at 0.2. Absence of packed bed lead high benzene conversion of 90% to polyaromatic hydrocarbons (PAHs) compared to similar low PAHs free benzene conversion of 32% achieved at both packed heights. In SPG composition effect, H2 and CH4 had a substantial inverse effect on benzene conversion. An increase in H2 concentration from 12 to 24 vol% increased the benzene conversion from 26 to 45% while an increase in CH4 concentration from 7 to 14 vol% reduced the benzene conversion from 28 to 4%. However, other SPG components had insignificant impacts on benzene conversion.

  • 12.
    Ahmad, Waqar
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Lin, Leteng
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Strand, Michael
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Coke-free conversion of benzene at high temperatures2023Ingår i: Journal of the Energy Institute, ISSN 1743-9671, E-ISSN 1746-0220, Vol. 109, artikel-id 101307Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This study investigates the conversion of benzene in a novel highly non-porous ɣ-Al2O3 packed bed reactor at 1000–1100 °C. The influences of packed bed presence, reforming medium (steam and CO2), gas flow rate and benzene concentration on steady state benzene conversion are examined. In presence of packed bed, benzene conversions of 52, 75, and 84% were achieved with combined steam and CO2 reforming at 1000, 1050, and 1100 °C, respectively. Whereas, benzene conversion of 65% without the packed bed at 1000 °C experienced a continuous increase in differential upstream pressure (DUP) of high temperature (HT) filter at reactor downstream due to deposition of in situ generated coke. High concentrations of generated CO and H2 of 2.3 and 6 vol% with packed bed than 1.4 and 4.7 vol% without the packed respectively, were achieved. CO2 reforming achieved high benzene conversions of 68–98% than 42–80% achieved with stream reforming at packed bed reactor temperatures of 1000–1100 °C. The results indicated that presence of ɣ-Al2O3 packed bed with possible surface reactions directed the conversion of benzene to combustible gases instead of coke. Hence, ɣ-Al2O3 packed bed reactor could be a suitable choice for coke-free conversion of tar of gasifier producer gas.

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  • 13.
    Ahmed, Mukhtiar
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Fluorine-Free Ionic Liquid Based Electrolytes: Synthesis and Structural Characterization2022Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Since their introduction by Sony in 1990, lithium-ion batteries (LIBs) have acquired a sizable market share. They have the best energy densities, a high open circuit voltage, a low self-discharge rate, no memory effect, and a slow loss of charge when not in use. These properties make them the most popular rechargeable batteries for portable gadgets, electric vehicles and aerospace applications.  They do, however, pose major safety issues since the electrolytes are made up of fluorinated salts dissolved in volatile organic solvents, the former being meta-stable at ambient temperature and the latter being flammable a with high vapour pressure. Thus, there is an urge to develop thermally and electrochemically stable non-fluorinated electrolytes to improve the safety and performance of batteries. Electrolytes based on ionic liquids (ILs) in general offer a range of suitable advantages including low volatility and high thermal and electrochemical stabilities,and can additionally be made fluorine-free. In general, their physicochemical properties are determined by the interactions between the cations and anions, which are controlled by the chemical functionalities present, with vast freedom in structural design to reduce these interactions and enhance also the ion mobilities. 

    In this study, favoring from of “structural design” three different families of fluorine-free ionic liquids-based electrolytes are designed and created. These families of ILs comprising n- tetrabutylphosphonium, imidazolium, pyridinium based cations and pyridine, pyrazine and ether functionalized salicylate-based anions. The structures and purity of these new ILs are characterized by using multinuclear NMR, FTIR and mass spectrometry. Several features and properties of the novel electrolytes are investigated; thermogravimetric analysis, differential scanning calorimetry, ionic conductivity and electrochemical stability. These studies are further complemented by using PFG NMR diffusometry to understand the possible interaction mechanisms between the oppositely charged ions within the electrolytes, and especially, the influence of Li+ addition in the IL-based electrolytes. 

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  • 14.
    Ahmed, Safiya
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik.
    Carlsson, Jesper
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik.
    Blomberg, Jenny
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik.
    Wiberg, Filip
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik.
    Biokol av avfallsfraktioner från IKEA:s möbeltillverkning2021Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    I dagens samhälle genereras en stor mängd avfall, där stora delar av avfallen förbränns vilket inte är gynnsamt för vare sig miljön eller klimatet. Därför finns det idag ett stort behov av klimatsmarta metoder där avfallen kan användas till att producera produkter som kan motverka klimatförändringar. Största delen av avfallen som genereras kommer från större företag som till exempel IKEA och de är i ständigt behov av nya metoder för att kunna använda sina avfall till klimatsmarta resurser. Att producera biokol av avfallen är en sådan klimatsmart metod, där biokolet är en hållbar produkt som både motverkar klimatförändringar och andra miljöproblem såsom övergödning. I denna rapport undersöktes två avfallsfraktioner från IKEA, vilka var Dust2k och Hogger. Det som undersöktes var hur lämpliga avfallsfraktionerna från IKEA är för produktion av biokol som skulle kunna appliceras i jordbruket samt hur denna lämplighet påverkas av avfallsfraktion och processförhållanden som används under pyrolysen.

    För att besvara frågeställningarna utfördes pyrolys på avfallsfraktionerna vid pyrolystemperaturerna 550℃ och 750℃, vilket gav fyra olika prover av biokol. Dessa prov analyserades med ett antal analysmetoder för att avgöra biokolets lämplighet som jordförbättrare och för att motverka klimatförändringar. De analyser som utfördes var elementaranalys, pH-mätning, termogravimetrisk analys (TGA), Brunauer-Emmet-Teller (BET) och svepelektronmikroskopi (SEM). Från pyrolysen och TGA kunde utbytet bestämmas, vilket uppgick till över 20% för samtliga prov. Elementaranalysen visade att biokol producerat av Hogger vid 900°C uppfyllde de EBC-krav som analyserades. Genom att mäta pH på avfallsfraktionerna samt biokolen gick det att se att pH höjdes under pyrolysen. Från BET och SEM erhölls information om porositet, ledningsförmåga och ytarea. Porositeten ökade med temperaturen och ledningsförmågan var högre för biokolet än biomassan. Ytarean låg mellan 347,2 m2/g och 422,8 m2/g och porvolymen mellan 0,173 cm3/g och 0,205 cm3/g. Det erhölls bäst egenskaper för avfallsfraktionen Hogger samt pyrolystemperaturen 750℃, vilket gjorde att slutsatsen att produktion av biokol från Hogger vid 750℃ lämpar sig bäst för användning som jordförbättrare kunde dras.

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    fulltext
  • 15.
    Aiello, R.
    et al.
    University of Calabria.
    Artioli, G.
    University of Milan.
    Carotenuto, L.
    MARS Center, Naples.
    Colella, C.
    University of Naples.
    Norby, P.
    University of Oslo.
    Sterte, Johan
    Zeolite synthesis in microgravity2005Ingår i: Topical teams in life & physical sciences: towards new research applications, Noordwijk, Netherlands: ESTEC , 2005, s. 78-85Kapitel i bok, del av antologi (Övrigt vetenskapligt)
    Abstract [en]

    The results of activities performed by the members of the Topical Team on 'Zeolites synthesis in microgravity' are discussed. A method was developed using a two-temperature synthesis procedure to distinguish between the nucleation and growth phase of the crystallization. The experiments have investigated the possibility of suppressing secondary nucleation by imposing a temperature gradient. Optical thickness of the solution has been monitored by interferometry. The Team, on the basis of findings, has elaborated a research program on zeolite film deposition that includes microgravity experimentation.

  • 16.
    Akhtar, Farid
    et al.
    Department of Materials and Environmental Chemistry, Stockholm University.
    Ojuva, Arto
    Stockholm University, Department of Materials and Environmental Chemistry.
    Mouzon, Johanne
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Hedlund, Jonas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Bergström, Lennart M.
    Department of Materials and Environmental Chemistry, Stockholm University.
    All-Zeolite Membranes2010Konferensbidrag (Refereegranskat)
  • 17.
    Akhtar, Farid
    et al.
    Stockholm University, Department of Materials and Environmental Chemistry.
    Ojuva, Arto
    Stockholm University, Department of Materials and Environmental Chemistry.
    Wirawan, Kompiang
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Hedlund, Jonas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Bergström, Lennart
    Stockholm University, Department of Materials and Environmental Chemistry.
    Hierarchically porous binder-free silicalite-1 discs: a novel support for all-zeolite membranes2011Ingår i: Journal of Materials Chemistry, ISSN 0959-9428, E-ISSN 1364-5501, Vol. 21, nr 24, s. 8822-8828Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Thermal expansion mismatch between the zeolite film and the support is an important cause for the formation of defects and cracks during the fabrication and use of zeolite membranes. We have studied how silicalite-1 discs with a permeability comparable to commercially available alumina supports can be produced by pulsed current processing (PCP) as a novel substrate for all-zeolite membranes. Hierarchically porous and mechanically strong membrane supports where the surface area and crystallography of the silicalite-1 particles were maintained could be obtained by carefully controlling the thermal treatment during PCP consolidation. In situ X-ray diffraction and dilatometry showed that the coefficient of thermal expansion (CTE) of the silicalite-1 substrate was negative in the temperature range 200-800 degrees C while the commonly used alumina substrate displayed a positive CTE. The critical temperature variation, Delta T, and thicknesses for crack-free supported zeolite films with a negative CTE were estimated using a fracture energy model. Zeolite films with a thickness of 1 mu m can only sustain a relatively modest Delta T of 100 degrees when supported onto alumina substrates while the all-zeolite membranes can support temperature variations above 500 degrees

  • 18.
    Akhtar, Farid
    et al.
    Department of Materials and Environmental Chemistry, Stockholm University.
    Ojuva, Arto
    Stockholm University, Department of Materials and Environmental Chemistry.
    Wirawan, Kompiang
    Hedlund, Jonas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Bergström, Lennart
    Department of Materials and Environmental Chemistry, Stockholm University.
    PCP procesing of Zeolite supports for all-zeolite membranes2011Konferensbidrag (Refereegranskat)
  • 19.
    Akhtar, Farid
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap. Department of Materials and Environmental Chemistry, Stockholm University, SE-10691 Stockholm, Sweden.
    Sjöberg, Erik
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Korelskiy, Danil
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Rayson, Mark
    Department of Chemistry, The University of Surrey, Guildford, Surrey GU2 7XH, UK.
    Hedlund, Jonas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Bergström, Lennart
    Department of Materials and Environmental Chemistry, Stockholm University, SE-10691 Stockholm, Sweden.
    Preparation of graded silicalite-1 substrates for all-zeolite membranes with excellent CO2/H2 separation performance2015Ingår i: Journal of Membrane Science, ISSN 0376-7388, E-ISSN 1873-3123, Vol. 493, s. 206-211Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    raded silicalite-1 substrates with a high gas permeability and low surface roughness have been produced by pulsed current processing of a thin coating of a submicron silicalite-1 powder onto a powder body of coarser silicalite-1 crystals. Thin zeolite films have been hydrothermally grown onto the graded silicalite-1 support and the all-zeolite membranes display an excellent CO2/H2 separation factor of 12 at 0 °C and a CO2 permeance of 21.3×10-7 mol m-2 s-1 Pa-1 for an equimolar CO2/H2 feed at 505 kPa and 101 kPa helium sweep gas. Thermal cracking estimates based on calculated surface energies and measured thermal expansion coefficients suggest that all-zeolite membranes with a minimal thermal expansion mismatch between the graded substrate and the zeolite film should remain crack-free during thermal cycling and the critical calcination step.

  • 20.
    Al Soubaihi, Rola Mohammad
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Saoud, Khaled Mohammad
    Virginia Commonwealth Univ Qatar, Liberal Arts & Sci Program, Doha, Qatar..
    Myint, Myo Tay Zar
    Sultan Qaboos Univ, Coll Sci, Dept Phys, POB 36, Muscat 123, Oman..
    Göthelid, Mats A.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Material- och nanofysik.
    Dutta, Joydeep
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Material- och nanofysik.
    CO Oxidation Efficiency and Hysteresis Behavior over Mesoporous Pd/SiO2 Catalyst2021Ingår i: Catalysts, E-ISSN 2073-4344, Vol. 11, nr 1, artikel-id 131Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Carbon monoxide (CO) oxidation is considered an important reaction in heterogeneous industrial catalysis and has been extensively studied. Pd supported on SiO2 aerogel catalysts exhibit good catalytic activity toward this reaction owing to their CO bond activation capability and thermal stability. Pd/SiO2 catalysts were investigated using carbon monoxide (CO) oxidation as a model reaction. The catalyst becomes active, and the conversion increases after the temperature reaches the ignition temperature (T-ig). A normal hysteresis in carbon monoxide (CO) oxidation has been observed, where the catalysts continue to exhibit high catalytic activity (CO conversion remains at 100%) during the extinction even at temperatures lower than T-ig. The catalyst was characterized using BET, TEM, XPS, TGA-DSC, and FTIR. In this work, the influence of pretreatment conditions and stability of the active sites on the catalytic activity and hysteresis is presented. The CO oxidation on the Pd/SiO2 catalyst has been attributed to the dissociative adsorption of molecular oxygen and the activation of the C-O bond, followed by diffusion of adsorbates at T-ig to form CO2. Whereas, the hysteresis has been explained by the enhanced stability of the active site caused by thermal effects, pretreatment conditions, Pd-SiO2 support interaction, and PdO formation and decomposition.

  • 21.
    Al-Badri, Tuqa
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi.
    Thermal degradation of PFAS in solid matter2024Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Per- och Polyfluorerade alkylsubstanser (PFAS) är syntetiskt framställda organiska föreningar som har använts i stor utsträckning i konsument- och industriprodukter. PFAS-substanser besitter attraktiva egenskaper såsom resistans mot väta, fett, fläckar och är dessutom värmetåliga. De används i bland annat brandskum, smink, vattentäta kläder med ”andas-funktion”, möbler och non- stickstekpannor. Den senaste forskningen har dock visat att PFAS utgör en fara för levande organismer och miljön. Vissa PFAS-substanser har klassats som persistenta, bioackumulativa och toxisk (PBT), samt väldigt persistenta och väldigt bioaccumulativa (vPvB).Existerande forskning har fokuserat på beteendet hos PFAS i olika miljöer. Dock finns det en kunskapslucka när det gäller hur dessa PFAS-substanser beter sig under termiska behandlingsprocesser, samt förbränningsgraden i kommersiella förbränningsanläggningar vid temperaturerna 850–950 °C. I detta projekt undersöks därför nedbrytningsgraden av PFAS genom förbränning samt bildning av potentiellt farliga biprodukter efter förbränning. För att genomföra denna studie skulle förbränning av PFAS-haltigt avloppsslam i en pilotskalig bubblande fluidiserad bädd (BFB) genomföras. På grund av hinder utfördes experimenten i stället i en konventionell och simpel laboratorieugn. Dessutom genomfördes en litteraturstudie för att undersöka bildandet av potentiellt farliga biprodukter efter förbränning av PFAS. Denna studie har visat att termisk behandling genom förbränning är en effektiv metod för att behandla PFAS i avloppsslam med reduktion under kvantifieringsgränserna. Undersökning av potentiellt farliga biprodukter baserat på litteraturstudier har visat att kortkedjiga PFCAs var mest förekommande i aska, vätska och gasformiga rester efter termisk behandling. Några undersökningar tyder på att termisk behandling av PFAS-haltigt material möjligen resulterar i ozonnedbrytande ämnen. Utifrån den genomförde litteraturstudien i detta projekt saknas starka bevis för att kunna påstå att det bildas ozonnedbrytande ämnen under förbränning av PFAS.

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    fulltext
  • 22.
    Aldaeus, Fredrik
    et al.
    RISE., Innventia.
    Schweinebarth, Hannah
    RISE., Innventia.
    Törngren, Per
    RISE., Innventia.
    Jacobs, Anna
    RISE., Innventia.
    Simplified determination of total lignin content in kraft lignin samples and black liquors2011Ingår i: Holzforschung, ISSN 0018-3830, E-ISSN 1437-434X, nr 4, s. 601-604Artikel i tidskrift (Refereegranskat)
  • 23.
    Alejo Vargas, Lucio Rodrigo
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Energiprocesser.
    Analysis of Negative Emission Ammonia Fertilizer (urea) Process2020Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    As the world population keeps increasing, ammonia-based fertilizers like urea are essential to provide food security. However, the current fertilizer industry is based on fossil fuel feedstock (mainly natural gas), making the production process CO2 emission-intensive. More specifically, besides the CO2 emitted during the process, the CO2 captured in urea is also released into the atmosphere after the fertilizer is applied to agricultural soils. Thus, positioning the fertilizer industry among the top four industrial emitters globally. Hence, in order to meet the target of limiting global warming to 1.5 ºC and achieve net-zero emissions by 2050, it is necessary to strengthen the carbon mitigation efforts in the current fertilizer industry. This can be achieved in different ways, such as using renewable biofuels and implementing technologies that can lead to zero/negative CO2 emissions.

    For that reason, the present study presents pathways to achieve a more environmentally friendly fertilizer production process. An overall analysis is performed if negative emissions can be achieved by replacing different fractions of natural gas (used as both feedstock and fuel) with biogas and biomethane and by capturing and storing the CO2 emitted from the process using chemical solvents as activated MDEA and MEA. The results obtained from the study revealed that negative emissions in fertilizer plant can be achieved by retrofitting an existing ammonia plant with a MEA based CO2 capture system (with a carbon capture rate of 90%) for the SMR burner flue gas, and by introducing 50% of biogas in the feedstock (alongside Natural gas), and 75% of biogas in the SMR burner fuel (alongside Natural gas). This initial approach would result in net negative emissions from urea's production and application and require approximately 0.5 kg of biogas per kg of urea produced in this case. Furthermore, the equivalent energy intensity for the negative emission urea plant would be 0.32% and 3.37% lower compared to the fossil fuel-based case without/with CCS, respectively. Ultimately, it is even possible to produce approximately 6% more urea product by replacing a particular fraction of natural gas with biogas. The reason for this increased production is due to the surplus of carbon dioxide by the introduction of biogas. It can be used along with the ammonia product going to storage in the fossil fuel-based case, where there was not enough CO2 to keep the feedstock molar ratio at the urea plant's inlet.

    Ladda ner fulltext (pdf)
    fulltext
  • 24.
    Alemrajabi, Mahmood
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Teknisk strömningslära.
    Ricknell, Jonas
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik.
    Samak, Sakarias
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik.
    Rodriguez Varela, Raquel
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik.
    Martinez, Joaquin
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Teknisk strömningslära.
    Hedman, Fredrik
    IVL Swedish Environmental Research Institute.
    Forsberg, Kerstin
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Resursåtervinning.
    Rasmuson, Åke C.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Teknisk strömningslära.
    Separation of Rare-Earth Elements Using Supported Liquid Membrane Extraction in Pilot Scale2022Ingår i: Industrial & Engineering Chemistry Research, ISSN 0888-5885, E-ISSN 1520-5045Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The use of supported liquid membrane extraction for recovery and separation of rare-earth elements (REEs) has been investigated. Experiments have been carried out using the different configurations: (1) standard hollow fiber supported liquid membrane operation (HFSLM), (2) renewal liquid membrane operation (HFRLM), and (3) emulsion pertraction technology (EPT). The experiments were performed in pilot scale using a hollow fiber module with a mass transfer surface area of 8 m2. Synthetic feed solution was used with compositions based on a process for recovery of REE from an apatite concentrate. The total concentration of REE in the feed was varied from 1 to 22 mM REE and the pH was varied in the range 1.5–3.2. Di(2-ethylhexyl) phosphoric acid (D2HEPA) diluted in kerosene, 10% (v/v), was used as the organic membrane solution, and 3 M HCl was used as stripping solution. In supported liquid membrane extraction, the extraction performance is governed by both the kinetics of REE transport through the membrane and by thermodynamics. The effect of feed composition on the selectivity and transport of REE through the liquid membrane have been investigated. The results show that the liquid membrane is more selective toward the heavy REE at lower pH values and higher REE concentration. HFRLM shows a higher transport rate than HFSLM, while the HFSLM configuration gives a higher selectivity toward individual REE. The membrane performance in HFSLM configuration rapidly decays with time, while in the HFRLM and EPT configurations, the performance is much more stable. Possible mechanisms for decaying membrane performance are discussed, and gel formation is identified as being of significant importance. Gel formation is observed at an organic loading above ∼46% for Nd, 38% for Y, 46% for Dy, and 65% for Er. The work performed in this study serves as an initial step to demonstrate that HFRLM and EPT can provide stable operation and be feasible options for processing of REE liquors. A process flow diagram for the recovery of the REE, present in the apatite concentrate, in three fractions is proposed based on the results from this study.

  • 25.
    Alevanau, Aliaksandr
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Tillämpad processmetallurgi.
    Study of pyrolysis and gasification of biomass from the self-organization perspective2015Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    This thesis focuses on the analysis of kinetics of i) low-temperature pyrolysis of gaseous hydrocarbons, ii) high-temperature steam gasification of char of wood pellets (>700oC), iii) high temperature pyrolysis of straw pellets in an atmosphere of argon and steam, and iv) high temperature pyrolysis of slices of transversally cut wooden sticks. The results of the kinetic measurements in the high-temperature cases are approximated using a least-square based optimization software, which was specially developed to analyse kinetics prone for deviation from the Arrhenius law.In the thesis a general analysis of the researched materials and kinetics of their pyrolysis and gasification is presented from the self-organization perspective. The energy transfer phenomena in both the pyrolysis and gasification processes of biomass are discussed with an emphasis on an analysis of basic phenomena involving the self-organized dynamics on fractal structures in the chosen biomass samples.

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    Alevanau_Thesis
  • 26. Ali, Asad
    et al.
    Laaksonen, Aatto
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK). Luleå University of Technology, Sweden; “Petru Poni” Institute of Macromolecular Chemistry, Romania; Nanjing Tech University, China.
    Huang, Guo
    Hussain, Shahid
    Luo, Shuiping
    Chen, Wen
    Shen, Pei Kang
    Zhu, Jinliang
    Ji, Xiaoyan
    Emerging strategies and developments in oxygen reduction reaction using high-performance platinum-based electrocatalysts2023Ingår i: Nano Reseach, ISSN 1998-0124, E-ISSN 1998-0000Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    The global practical implementation of proton exchange membrane fuel cells (PEMFCs) heavily relies on the advancement of highly effective platinum (Pt)-based electrocatalysts for the oxygen reduction reaction (ORR). To achieve high ORR performance, electrocatalysts with highly accessible reactive surfaces are needed to promote the uncovering of active positions for easy mass transportation. In this critical review, we introduce different approaches for the emerging development of effective ORR electrocatalysts, which offer high activity and durability. The strategies, including morphological engineering, geometric configuration modification via supporting materials, alloys regulation, core-shell, and confinement engineering of single atom electrocatalysts (SAEs), are discussed in line with the goals and requirements of ORR performance enhancement. We review the ongoing development of Pt electrocatalysts based on the syntheses, nanoarchitecture, electrochemical performances, and stability. We eventually explore the obstacles and research directions on further developing more effective electrocatalysts.

     

  • 27.
    Al-Soubaihi, Rola
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Saoud, Khaled Mohammad
    Virginia Commonwealth Univ Qatar, Liberal Arts & Sci Program, POB 8095, Doha, Qatar..
    Awadallah-F, Ahmed
    Qatar Univ, Dept Chem Engn, POB 2713, Doha, Qatar..
    Elkhatat, Ahmed Mohamed
    Qatar Univ, Dept Chem Engn, POB 2713, Doha, Qatar..
    Al-Muhtaseb, Shaheen A.
    Qatar Univ, Dept Chem Engn, POB 2713, Doha, Qatar..
    Dutta, Joydeep
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Material- och nanofysik.
    Investigation of palladium catalysts in mesoporous silica support for CO oxidation and CO2 adsorption2023Ingår i: Heliyon, E-ISSN 2405-8440, Vol. 9, nr 7, artikel-id e18354Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The oxidation of Carbon monoxide (CO) to Carbon dioxide (CO2) is one of the most extensively investigated reactions in the field of heterogeneous catalysis, and it occurs via molecular rearrangements induced by catalytic metal atoms with oxygen intermediates. CO oxidation and CO2 capture are instrumental processes in the reduction of green-house gas emissions, both of which are used in low-temperature CO oxidation in the catalytic converters of vehicles. CO oxidation and CO2 adsorption at different temperatures are evaluated for palladium-supported silica aerogel (Pd/SiO2). The synthesized catalyst was active and stable for low-temperature CO oxidation. The catalytic activity was enhanced after the first cycle due to the reconditioning of the catalyst's pores. It was found that the presence of oxide forms of palladium in the SiO2 microstructure, influences the performance of the catalysts due to oxygen vacancies that increases the frequency of active sites. CO2 gas adsorption onto Pd/SiO2 was investigated at a wide-ranging temperature from 16 to 120 degrees C and pressures similar to 1 MPa as determined from the isotherms that were evaluated, where CO2 showed the highest equilibrium adsorption capacity at 16 degrees C. The Langmuir model was employed to study the equilibrium adsorption behavior. Finally, the effect of moisture on CO oxidation and CO2 adsorption was considered to account for usage in real-world applications. Overall, mesoporous Pd/SiO2 aerogel shows potential as a material capable of removing CO from the environment and capturing CO2 at low temperatures.

  • 28.
    Altantzis, Ikaros
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik.
    Enhancing Mineral Carbonation of Olivine with CO22023Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Koldioxidutsläpp (CO2) från energiproduktionsindustrin och transportsektorn globalt påverkar miljön negativt. Länder har enats om att minska utsläppen för att nå målet om en genomsnittlig temperaturökning på 1,5 °C till 2030. Trots detta förväntas de globala utsläppen av CO2 från fossila bränslen och industriella processer vara cirka 40 Gton per år fram till 2100.

    För att dra nytta av CO2-utsläppen och skapa värdefulla produkter med negativa utsläpp är mineralkarbonatisering en önskvärd process. Denna process innebär att CO2 och mineraler löses upp i en alkalisk lösning och bildar stabila produkter. Faktorer som partikelstorlek hos mineralerna och CO2-lösningshastigheten påverkar mineralkarbonatiseringens hastighet.

    Experiment utfördes med en batchreaktor från Paebbl AB och en matematisk modell utvecklades i Matlab. Resultaten jämfördes för olika partikelstorlekar i tre motståndsfall. Större partikelstorlek hos olivin visade sig öka tiden för total konvertering, oavsett motståndstyp. De modellerade motstånden beskrev inte tillräckligt processen och indikerade att alla tre motstånd har en samtidig och enhetlig effekt på olivinmineralisering, utöver eventuella begränsningar som föroreningar och biprodukter. Mineraliseringsexperiment med 20 μm partiklar under en timme gav 34,4% omvandling, medan 10 μm partiklar under två timmar gav 46,7% omvandling. En inledande undersökning av massöverföringsbegränsningar visade att CO2-lösningshastigheten inte är den begränsande faktorn, utan lägre omrörningshastigheter och beteendet hos (CO2 + olivin)-systemet behöver ytterligare studeras. Framtida forskning bör fokusera på att lösa dessa begränsningar.

    Ladda ner fulltext (pdf)
    fulltext
  • 29.
    Alvfors, Per
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Energiprocesser.
    Arnell, Jenny
    IVL.
    Berglin, Niklas
    Innventia.
    Björnsson, Lovisa
    LU.
    Börjesson, Pål
    LU.
    Grahn, Maria
    Chalmers/SP.
    Harvey, Simon
    Chalmers.
    Hoffstedt, Christian
    Innventia.
    Holmgren, Kristina
    IVL.
    Jelse, Kristian
    IVL.
    Klintbom, Patrik
    Kusar, Henrik
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk teknologi.
    Lidén, Gunnar
    LU.
    Magnusson, Mimmi
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Energiprocesser.
    Pettersson, Karin
    Chalmers.
    Rydberg, Tomas
    IVL.
    Sjöström, Krister
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik.
    Stålbrand, Henrik
    LU.
    Wallberg, Ola
    LU.
    Wetterlund, Elisabeth
    LiU.
    Zacchi, Guido
    LU.
    Öhrman, Olof
    ETC Piteå.
    Research and development challenges for Swedish biofuel actors – three illustrative examples: Improvement potential discussed in the context of Well-to-Tank analyses2010Rapport (Övrigt vetenskapligt)
    Abstract [en]

    Currently biofuels have strong political support, both in the EU and Sweden. The EU has, for example, set a target for the use of renewable fuels in the transportation sector stating that all EU member states should use 10% renewable fuels for transport by 2020. Fulfilling this ambition will lead to an enormous market for biofuels during the coming decade. To avoid increasing production of biofuels based on agriculture crops that require considerable use of arable area, focus is now to move towards more advanced second generation (2G) biofuels that can be produced from biomass feedstocks associated with a more efficient land use. Climate benefits and greenhouse gas (GHG) balances are aspects often discussed in conjunction with sustainability and biofuels. The total GHG emissions associated with production and usage of biofuels depend on the entire fuel production chain, mainly the agriculture or forestry feedstock systems and the manufacturing process. To compare different biofuel production pathways it is essential to conduct an environmental assessment using the well-to-tank (WTT) analysis methodology. In Sweden the conditions for biomass production are favourable and we have promising second generation biofuels technologies that are currently in the demonstration phase. In this study we have chosen to focus on cellulose based ethanol, methane from gasification of solid wood as well as DME from gasification of black liquor, with the purpose of identifying research and development potentials that may result in improvements in the WTT emission values. The main objective of this study is thus to identify research and development challenges for Swedish biofuel actors based on literature studies as well as discussions with the the researchers themselves. We have also discussed improvement potentials for the agriculture and forestry part of the WTT chain. The aim of this study is to, in the context of WTT analyses, (i) increase knowledge about the complexity of biofuel production, (ii) identify and discuss improvement potentials, regarding energy efficiency and GHG emissions, for three biofuel production cases, as well as (iii) identify and discuss improvement potentials regarding biomass supply, including agriculture/forestry. The scope of the study is limited to discussing the technologies, system aspects and climate impacts associated with the production stage. Aspects such as the influence on biodiversity and other environmental and social parameters fall beyond the scope of this study. We find that improvement potentials for emissions reductions within the agriculture/forestry part of the WTT chain include changing the use of diesel to low-CO2-emitting fuels, changing to more fuel-efficient tractors, more efficient cultivation and manufacture of fertilizers (commercial nitrogen fertilizer can be produced in plants which have nitrous oxide gas cleaning) as well as improved fertilization strategies (more precise nitrogen application during the cropping season). Furthermore, the cultivation of annual feedstock crops could be avoided on land rich in carbon, such as peat soils and new agriculture systems could be introduced that lower the demand for ploughing and harrowing. Other options for improving the WTT emission values includes introducing new types of crops, such as wheat with higher content of starch or willow with a higher content of cellulose. From the case study on lignocellulosic ethanol we find that 2G ethanol, with co-production of biogas, electricity, heat and/or wood pellet, has a promising role to play in the development of sustainable biofuel production systems. Depending on available raw materials, heat sinks, demand for biogas as vehicle fuel and existing 1G ethanol plants suitable for integration, 2G ethanol production systems may be designed differently to optimize the economic conditions and maximize profitability. However, the complexity connected to the development of the most optimal production systems require improved knowledge and involvement of several actors from different competence areas, such as chemical and biochemical engineering, process design and integration and energy and environmental systems analysis, which may be a potential barrier.

  • 30.
    Amara, Soumia
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Energiprocesser.
    CO2 capture in industry using chilled ammonia process2021Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    CO2 capture and storage (CCS) is estimated to reduce 14% of the global CO2 emissions in the 2 °C scenario presented by the International Energy Agency. Moreover, post combustion capture is identified as a potential method for CO2 capture from industry since it can be easily retrofitted without disturbing the core industrial process. Among the post-combustion capture methods, absorption using mono-ethanol amine (MEA) is the most mature technology that has been demonstrated at plant scale. However, using chilled ammonia process as a post combustion capture technology in a cement industry can reduce 47% energy penalty for CO2 capture when compared to the conventional MEA absorption method. 

    Hence, the current project aims at analyzing the chilled ammonia process when integrated with steel and ammonia plants. Key performance indicator like specific primary energy consumption per kilogram of CO2 avoided (SPECCA) is estimated and compared with MEA absorption method. Firstly, chilled ammonia process (CAP) for cement plant was used as reference case. Then, CAP for steel and ammonia processes was optimized by the means of the decision variables affecting the capture and energy efficiency. The energy consumption per kg CO2 captured and SPECCA was lower for the higher CO2 concentration in the flue gas. Results for SPECCA were 3,56, 3,52 and 3,61 MJ/kg CO2 for cement, steel, and ammonia plants, respectively. 

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  • 31.
    Amari, Abdelfattah
    et al.
    Department of Chemical Engineering, College of Engineering, King Khalid University, Abha, Saudi Arabia; Research Laboratory of Processes, Energetics, Environment and Electrical Systems, National School of Engineers of Gabes, Gabes University, Gabes, Tunisia.
    Noreen, Ayesha
    Department of Social Environmental Sciences, Faculty of Language History and Geography, Ankara University, Ankara, Turkey.
    Osman, Haitham
    Department of Chemical Engineering, College of Engineering, King Khalid University, Abha, Saudi Arabia.
    Sammen, Saad Sh.
    Department of Civil Engineering, College of Engineering, University of Diyala, Diyala, Iraq.
    Al-Ansari, Nadhir
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Salman, Hayder Mahmood
    Department of Computer Science, Al-Turath University College Al Mansour, Baghdad, Iraq.
    Investigation of the viable role of oil sludge-derived activated carbon for oily wastewater remediation2023Ingår i: Frontiers in Environmental Science, E-ISSN 2296-665X, Vol. 11, artikel-id 1138308Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A wide range of studies has been carried out to describe the equilibrium data of adsorption for the surface adsorption process. However, no extensive investigation has been carried out to evaluate the oil sludge based activated carbon surface adsorption. Therefore, the possibility of carbon active production using different oil sludges and consequently the adsorption mechanism of these kind of adsorbents is still unknown. In this study, a novel low-cost approach was introduced to synthesize the activated carbon using oil sludge applying a two-step process including carbonization and chemical activation. In this way, four different types of oil sludges were characterized and then applied to synthesize different carbon actives and their performance were investigated as an adsorbent. The results showed that all synthesized activated carbons, with about 6% ash and pH = 7 and the specific surface area of 110 m2/gr, have the ability to treatment of oily wastewater; which can be referred to the high carbon content (>80%). The iodine number and the efficiency of prepared activated carbon were obtained as 406.8 mg/g and 94%, respectively. The adsorption process was also studied at different process conditions such as temperature (308–338 K), pH value (3–9) and adsorbent amount (50–200 mg/L) to find the optimum condition for wastewater treatment. The results show that the pH value has an optimum in the adsorption rate (the maximum adsorption was measured at pH = 5) and the adsorption capacity can be reduced by increasing the temperature or decreasing the adsorbent amount. Moreover, three different adsorption isotherm models were applied, i.e., Langmuir, Temkin, and Freundlich isotherms; which the Langmuir equation was more suitable than others investigated isotherm models with R2 ≈ 0.999.

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  • 32.
    Amjad, Um-e-Salma
    et al.
    Department of Chemical Engineering, COMSATS University Islamabad, Lahore Campus, Defence Road, Off Raiwind Road, Lahore 54000, Pakistan.
    Tajjamal, Arshia
    Department of Chemical Engineering, COMSATS University Islamabad, Lahore Campus, Defence Road, Off Raiwind Road, Lahore 54000, Pakistan.
    Ul-Hamid, Anwar
    Core Research Facilities, King Fahd University of Petroleum & Minerals, Dhahran 31261, Saudi Arabia.
    Faisal, Abrar
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik. Department of Chemical Engineering, COMSATS University Islamabad, Lahore Campus, Defence Road, Off Raiwind Road, Lahore 54000, Pakistan.
    Zaidi, Syed Ammar Hussain
    Department of Chemical Engineering, COMSATS University Islamabad, Lahore Campus, Defence Road, Off Raiwind Road, Lahore 54000, Pakistan.
    Sherin, Lubna
    Department of Chemistry, COMSATS University Islamabad, Lahore Campus, Defence Road, Off Raiwind Road, Lahore 54000, Pakistan.
    Mir, Amna
    Department of Physics, COMSATS University Islamabad, Lahore Campus, Defence Road, Off Raiwind Road, Lahore 54000, Pakistan.
    Mustafa, Maria
    Department of Chemical Engineering, COMSATS University Islamabad, Lahore Campus, Defence Road, Off Raiwind Road, Lahore 54000, Pakistan.
    Ahmad, Nabeel
    Department of Chemical Engineering, COMSATS University Islamabad, Lahore Campus, Defence Road, Off Raiwind Road, Lahore 54000, Pakistan.
    Hussain, Murid
    Department of Chemical Engineering, COMSATS University Islamabad, Lahore Campus, Defence Road, Off Raiwind Road, Lahore 54000, Pakistan.
    Park, Young-Kwon
    School of Environmental Engineering, University of Seoul, Seoul 02504, Republic of Korea.
    Catalytic cracking of polystyrene pyrolysis oil: Effect of Nb2O5 and NiO/Nb2O5 catalyst on the liquid product composition2022Ingår i: Waste Management, ISSN 0956-053X, E-ISSN 1879-2456, Vol. 141, s. 240-250Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The catalytic cracking of polystyrene pyrolysis oil was investigated over a Nb2O5 and a NiO/Nb2O5 catalyst in a fixed bed reactor. First, the pyrolysis of two different polystyrene feedstock (polystyrene foam and polystyrene pellet) was carried out in a semi-batch reactor, and the resulting polystyrene pellets pyrolysis oil was selected for catalytic cracking reaction because of its high liquid yield (85%). Catalytic cracking experiments were then performed at different temperatures (350–500 °C) using Nb2O5 or NiO/Nb2O5 catalyst. Gas chromatography–mass spectrometry analysis of liquid product obtained from the catalytic cracking process showed that the dimers in the pyrolysis oil were converted to monomers during the catalytic cracking process. The catalytic cracking results also showed that the NiO/Nb2O5 catalyst (having slightly higher acidic sites) had slightly higher activity for monomer conversion than the Nb2O5 catalyst (having less acidic sites). X-ray diffraction, transmission electron microscopy, pyridine Fourier transform infrared spectroscopy, NH3 Temperature Programmed Desorption and X-ray photoelectron spectroscopy were used to characterize the catalyst. The highest catalytic cracking activity was observed at 400 °C with the Nb2O5 catalyst with 4% toluene, 6% ethylbenzene, approximately 50% styrene, 13% α-methyl styrene, and only 6% of dimers in the liquid oil. The increase in temperature positively affected the yield of gases during catalytic cracking process.

  • 33.
    Andersson, Anna
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    CFD optimization of photochemical UV reactors for VOC degradation2017Självständigt arbete på avancerad nivå (yrkesexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    In 2016 the World Health Organization released a report on Ambient Air Pollution, in this it was stated that one out of every nine deaths all around the world in 2012 were due to air-pollution-related conditions. Urban air pollution involves a broad range of compounds from many diverse sources. Volatile Organic Compounds (VOCs) are some of the important compounds. Almost all VOCs are known to have effect on human health, many of them are carcinogenic. VOCs also contribute to the ground level photochemical smog and the reduction of the stratospheric ozone layer. Therefore, it is important to control the emissions of VOCs from industries and restaurants.

    Today most big scale VOC removal is done by thermal or catalytic incineration. While smaller scale air purification is done by using adsorbing materials such as activated carbon. Both these methods have their drawbacks. A promising technology, which is also environmentally friendly, is UV reactors.

    This thesis is a collaboration with the company Centriair, a company developing and selling UV reactors mainly for odor removal. The UV reactors which are in use today show acceptable performance, with a conversion of 50-60%. However, they have yet to be optimized to get the most out of the reactors. The aim was to try to reach an as high conversion of VOCs as possible in a prototype scale compared to a reference reactor, also in prototype scale. The reactors were simulated using the Computational Fluid Dynamic (CFD) software COMSOL Multiphysics® 5.2a. The simulation was based on earlier lab scale experiments with UV reactors.

    The conclusion from doing this thesis is that the most important challenge with a UV reactor up-scaling and optimization is the dark zones and the bypassing effect given by these. It is very important that the irradiation reaches the whole reactor and that all gas is affected by it. It is also important that the gas is given time to stay by the light sources as long as possible. Two reactors in this thesis had very high conversion results and thus showed potential of being very effective UV reactors. These two reactors showed conversion results of 45% respective 61% higher than the reference reactor used by Centriair today.

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  • 34.
    Andersson, Charlotte
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser.
    Factors affecting MFI membrane quality2007Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Zeolites are crystalline aluminosilicates with molecular sieving properties and are widely used in industrial applications such as catalysis, sorption and ion-exchange. Zeolite membranes are highly interesting due to their capability to continuously separate molecules under severe conditions. The MFI zeolite structure has suitable pore diameter for many applications, and its thermal and chemical stability is high. In order to obtain high performance MFI membranes, a thin and defect free film is needed for high flux and high selectivity. In this thesis, parameters affecting quality of zeolite membranes have been investigated. Different MFI-zeolite membranes were prepared using seed crystals and hydrothermal synthesis. Thereafter, membranes were characterized using scanning electron microscopy, single gas permeation measurements, porosimetry and separation experiments. The effect of grain boundaries was investigated by preparing membranes with small crystal size. It was found that a high amount of grain boundaries reduced the quality of the membranes. In another study, the effect of exposure to aqueous solutions was found to increase the amount of non-zeolitic pores in the membrane, and thus it decreased the quality of the membrane. However, no such effect was found for ethanol that was identified as a safe rinsing media. Membranes with different Si/Al ratio were also prepared and evaluated. It was observed that the Si/Al ratio of a MFI membrane influences the performance of the membrane. It was found that an increase of aluminium makes the membrane more polar which leads to an improved adsorption of, and selectivity for polar molecules. The effect of support invasion was also evaluated and the regularity and extension of the support invasion was observed to affect membrane quality. The effect of heating rate during calcination was investigated and no correlation between heating rate and membrane quality was observed. Calcination of membranes was studied in-situ by high temperature synchrotron radiation and a model for crack formation was postulated. In summary, this work has shown that in order to obtain high quality membranes, the amount of grain boundaries, the film thickness and support invasion should be controlled. To obtain the best performance of the membranes the Si/Al ratio should be chosen with respect to the application. Finally, water exposure affects the lifetime of the MFI membranes in certain applications.

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  • 35.
    Andersson, Charlotte
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser.
    Properties of molecular sieve membranes2004Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Zeolites are crystalline aluminosilicates with molecular sieving properties and are widely used in industry for catalysis, sorption and ion-exchange applications. Zeolite membranes are commercially interesting since this technology may be employed for continuous separation of molecules under severe conditions. MFI zeolite has suitable pore diameter for many applications and relatively high thermal and chemical stability. Zeolite films in membranes must be thin, to obtain a high flux and free from defects for high selectivity. Many parameters are affecting the properties of zeolite films and in this thesis some of them are investigated. MFI zeolite membranes were prepared using seed crystals and hydrothermal synthesis and characterized with scanning electron microscopy, single gas permeation measurements, porosimetry and separation experiments. Membranes grown in one or several steps with seeding in-between the synthesis steps were compared. It was observed that membranes comprised of small crystals and consequently high concentration of grain boundaries had low separation performance. Grain boundaries could also be opened by extensive rinsing, which reduced membrane quality. The influence of the calcination rate on the performance of zeolite membranes of a particular type was also studied. It was demonstrated that the calcination rate does not affect the membrane quality.

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  • 36. Andersson, Charlotte
    et al.
    Hedlund, Jonas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Effects of exposure to water and ethanol on silicalite-1 membranes2008Ingår i: Journal of Membrane Science, ISSN 0376-7388, E-ISSN 1873-3123, Vol. 313, nr 1-2, s. 120-126Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The effects of long exposures to ethanol, water and 0.1 M aqueous solutions of ammonia, sodium hydroxide, tetrapropylammonium hydroxide (TPAOH) and hydrochloric acid on thin TPA-silicalite-1 membranes were studied. Single gas permeation experiments, porosimetry and scanning electron microscopy were used to characterize the membranes. It was found that a short exposure (24 h) will only dissolve synthesis residues and will not affect membrane quality negatively. The only medium that had an effect after 24 h was sodium hydroxide, which almost dissolved the film completely. After exposing TPA-silicalite-1 membranes for 30 days in the various liquids, the membrane quality decreased in the order ethanol < 0.1 M hydrochloric acid < 0.1 M TPAOH < water < 0.1 M ammonia < 0.1 M sodium hydroxide due to dissolution of the silicalite-1 crystals. This study has shown that prolonged exposure to aqueous solutions will lead to dissolution of silicalite-1 crystals causing an increase in micro- and mesopores in the film. The amount and size of the pores will depend on the pH of the aqueous medium. Higher pH gives a higher dissolution and hence more non-zeolitic pores in the silicalite-1 film. Ethanol has no effect on the dissolution of the zeolite film even after 30 days. This finding has an effect in membrane preparation and in several membrane applications such as pervaporation and separation of hydrocarbons isomer mixtures.

  • 37. Andersson, Charlotte
    et al.
    Hedlund, Jonas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Jareman, Fredrik
    Luleå tekniska universitet.
    Sterte, Johan
    Silicalite-1 membranes with small crystal size2004Ingår i: Recent advances in the science and technology of zeolites and related materials. Part A: proceedings of the 14th International Zeolite Conference, Amsterdam: Elsevier, 2004, s. 626-631Konferensbidrag (Refereegranskat)
    Abstract [en]

    Silicalite-1 membranes with small crystal size were prepared using a multiseeding method, where the support was repeatedly seeded and exposed to a short hydrothermal treatment up to five times. The film were characterized using SEM, single gas permeation, porosimetry and mixture separation experiment Films with three or four layers were of high quality i.e with minor defects according to the porosimetry experiments but showed poor separation of binary mixtures. This result may be attributed to the small crystal size and/or large amount of grain boundaries in the films.

  • 38.
    Andersson, Filippa
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Energiprocesser.
    Integrating biomass gasification with electric arc furnace steel making2023Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Utsläppen av växthusgaser ökar över hela världen och nya tekniker används för att minska utsläppen. 7% av utsläppen kommer från stålsektorn. 25% av världens stålproduktion görs via återvinningstekniken ljusbågsugn. Genom återvinningsprocessen släpps det ut 500kg CO2 per ton producerat flytande stål. En möjlighet att sänka dessa direkta utsläppär att koppla ljusbågsugnsprocessen med biomassa förgasnings och koldioxidavskiljning. Den föreslagna lösningen i denna avhandling är att utnyttja avgaserna från stålsmältningen i förgasningsprocessen och skapa värdefulla produkter. Projektet utvärderar den tekniska genomförbarheten i form av energieffektivitet och kolutnyttjande. Den föreslagna processen simulerades med Aspen Plus.

    Ett problem med ljusbågsugnens avgaser är fluktuationen i sammansättningen. Tre fall avavgassammansättning undersöktes. Fall 1 var den genomsnittliga avgassammansättningen, medan fall 2 och 3 var extrema med högt CO- respektive CO2-innehåll. Resultatet visade att syntetsgassammansättningen starkt beror på förgasningsmedlet. I samtliga fall ökade energieffektiviteten och de direkta utsläppen minskade, jämfört med nuvarande process. Fall 1 visade generellt högst effektivitet och kolutnyttjande, medan det CO2 rika fallet (fall 3) hade lägst. Ett kontinuerligt flöde av förgasningsmedel krävs för att driva förgasningsprocessen. Eftersom ljusbågsugn är en satsvis process, sker luftförgasning när avgaser inte är tillgängliga. Det önskade resultatet av luftförgasning är att producera syntetsgas som liknar avgasförgasningens syntesgas. Resultaten visade att luftinfiltration i avgaser är gynnsamt för mer liknande syntesgas .

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  • 39.
    Andersson, Joakim
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Energiprocesser.
    Improving the economics of fossil-free steelmaking via co-production of methanolManuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    Steelmaking is responsible for 7% of the global net emissions of carbon dioxide and heavily reducing emissions from currently dominating steelmaking processes is difficult and costly. Recently, new steelmaking processes based on the reduction of iron ore with hydrogen (H2) produced via water electrolysis have been suggested. If the electricity input to such processes is fossil-free, near-zero carbon dioxide emissions steelmaking is achievable. However, the high electricity demand of electrolysis is a significant implementation barrier. A H2 storage may alleviate this via allowing a larger share of H2 to be produced at low electricity prices. However, accurately forecasting the dynamics of electricity markets is challenging. This increases the risk of investment in a H2 storage. Here we evaluate a novel methanol-based H2 storage concept for a H2-based steelmaking process that also allows for the co-production of methanol. During electricity price peaks, the methanol can be reformed to produce H2 for the steelmaking process. During prolonged periods of low electricity prices, excess methanol can be produced and sold off, thus improving the prospects of storage profitability. We use historical electricity prices and a process model to evaluate methanol-fossil-free steel co-production schemes. Methanol co-production has the potential to improve the economics of H2 supply to a fossil-free steelmaking process by up to an average of 0.40 €/kg H2 across considered scenarios, equivalent to a reduction in H2 production electricity costs of 25.0%.

  • 40.
    Andersson, Joakim
    KTH, Skolan för kemivetenskap (CHE).
    Lifetime estimation of lithium-ion batteries for stationary energy storage system2017Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    With the continuing transition to renewable inherently intermittent energy sources like solar- and wind power, electrical energy storage will become progressively more important to manage energy production and demand. A key technology in this area is Li-ion batteries. To operate these batteries efficiently, there is a need for monitoring of the current battery state, including parameters such as state of charge and state of health, to ensure that adequate safety and performance is maintained. Furthermore, such monitoring is a step towards the possibility of the optimization of battery usage such as to maximize battery lifetime and/or return on investment. Unfortunately, possible online measurements during actual operation of a lithium-ion battery are typically limited to current, voltage and possibly temperature, meaning that direct measurement of battery status is not feasible. To overcome this, battery modeling and various regression methods may be used. Several of the most common regression algorithms suggested for estimation of battery state of charge and state of health are based on Kalman filtering. While these methods have shown great promise, there currently exist no thorough analysis of the impact of so-called filter tuning on the effectiveness of these algorithms in Li-ion battery monitoring applications, particularly for state of health estimation. In addition, the effects of only adjusting the cell capacity model parameter for aging effects, a relatively common approach in the literature, on overall state of health estimation accuracy is also in need of investigation.

    In this work, two different Kalman filtering methods intended for state of charge estimation: the extended Kalman filter and the extended adaptive Kalman filter, as well as three intended for state of health estimation: the dual extended Kalman filer, the enhanced state vector extended Kalman filer, and the single weight dual extended Kalman filer, are compared from accuracy, performance, filter tuning and practical usability standpoints. All algorithms were used with the same simple one resistor-capacitor equivalent circuit battery model. The Li-ion battery data used for battery model development and simulations of filtering algorithm performance was the “Randomized Battery Usage Data Set” obtained from the NASA Prognostics Center of Excellence. 

    It is found that both state of charge estimators perform similarly in terms of accuracy of state of charge estimation with regards to reference values, easily outperforming the common Coulomb counting approach in terms of precision, robustness and flexibility. The adaptive filter, while computationally more demanding, required less tuning of filter parameters relative to the extended Kalman filter to achieve comparable performance and might therefore be advantageous from a robustness and usability perspective. Amongst the state of health estimators, the enhanced state vector approach was found to be most robust to initialization and was also least taxing computationally. The single weight filter could be made to achieve comparable results with careful, if time consuming, filter tuning. The full dual extended Kalman filter has the advantage of estimating not only the cell capacity but also the internal resistance parameters. This comes at the price of slow performance and time consuming filter tuning, involving 17 parameters. It is however shown that long-term state of health estimation is superior using this approach, likely due to the online adjustment of internal resistance parameters. This allows the dual extended Kalman filter to accurately estimate the SoH over a full test representing more than a full conventional battery lifetime. The viability of only adjusting the capacity in online monitoring approaches therefore appears questionable. Overall the importance of filter tuning is found to be substantial, especially for cases of very uncertain starting battery states and characteristics.

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  • 41.
    Andersson, Joakim
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Energiprocesser.
    Non-geological hydrogen storage for fossil-free steelmaking2022Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [sv]

    Den globala stålanvändningen har mer än tredubblats under de senaste 50 åren och ytterligare tillväxt förväntas, framförallt i utvecklingsländer. Ståltillverkning står dock för 7 % av de globala nettoutsläppen av koldioxid (CO2) och möjligheter till ytterligare optimering av nuvarande processer för järnmalmsreduktion baserade på fossila bränslen är begränsade. Nya ståltillverkningsmetoder krävs därför för att etablerade klimatmål ska kunna uppnås. En väg framåt är järnmalmsreduktion med vätgas (H2) producerad via elektrolys. En utmaning är elektrolysens stora elbehov. Ett H2-lager kan reducera elkostnaden för elektrolys genom att tillåta att en större andel H2 produceras när elpriset är lågt. Befintlig erfarenhet av storskalig H2-lagring är helt begränsad till saltkaverner i geologiska saltformationer och dessa finns inte att tillgå överallt. Icke-geologiska H2-lagringstekniker har dock inte tidigare utvärderats för H2-baserad ståltillverkning, vilket är syftet med denna avhandling. Flytande H2-bärare identifierades som de mest tekno-ekonomiskt gångbara alternativen för icke-geologisk H2-lagring. Av dessa bärare befanns metanol (CH3OH) vara särskilt lovande för H2-baserad ståltillverkning på grund av det låga värmebehovet för dess dehydrogenering, dess låga lagringskostnad och för att processer för både dess produktion och dehydrogenering har en hög teknisk mognadsgrad. Ett komplett CH3OH-baserat lagringskoncept för H2-baserad ståltillverkning utvecklades, inklusive processer för CO2- och värmeförsörjning. Detta koncepts förmåga att minska kostnaden för H2-baserad ståltillverkning utvärderades via en deterministisk optimeringsmetod baserad på historiska elpriser. Resultat indikerar att H2-lagring i CH3OH kan vara konkurrenskraftigt med geologisk lagring, särskilt i särskilt i scenarier med ihållande perioder med höga elpriser.  Vidare undersöktes även möjligheter att inkludera försäljning av CH3OH i lagringskonceptet. Resultat visar att sådan försäljning kan minska risken för investering i ett CH3OH-baserat H2-lager som en del av en H2-baserad ståltillverkningsprocess då det gör det möjligt för lagret att nå lönsamhet under mer varierade elmarknadsförhållanden.

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  • 42.
    Andersson, Joakim
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Energiprocesser.
    Krüger, Andries
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi.
    Grönkvist, Stefan
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Energiprocesser.
    Methanol as a carrier of hydrogen and carbon in fossil-free production of direct reduced iron2020Ingår i: Energy Conversion and Management: X, ISSN 2590-1745, Vol. 7, nr 100051Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Steelmaking is responsible for around 7% of the global emissions of carbon dioxide and new steelmaking processes are necessary to reach international climate targets. As a response to this, steelmaking processes based on the direct reduction of iron ore by hydrogen produced via water electrolysis powered by renewable electricity have been suggested. Here we present a novel variant of hydrogen-based steelmaking incorporating methanol as a hydrogen and carbon carrier together with high-temperature co-electrolysis of water and carbon dioxide and biomass oxy-fuel combustion. The energy and mass balances of the process are analyzed. It is found that this methanol-based direct reduction process may potentially offer a number of process-related advantages over a process based on pure hydrogen, featuring several process integration options. Notably, the electricity and total energy use of the steelmaking process could be reduced by up to 25% and 8% compared to a reference pure-hydrogen process, respectively. The amount of high-temperature (>200 °C) heat that must be supplied to the process could also be reduced by up to approximately 34%, although the demand for medium-temperature heat is substantially increased. Furthermore, the suggested process could allow for the production of high-quality direct reduced iron with appropriate carburization to alleviate downstream processing in an electric arc furnace, which is not the case for a process based on pure hydrogen.

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  • 43.
    Andersson, Joel
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Larsson, Roland
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Almqvist, Andreas
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Grahn, Mattias
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Minami, Ichiro
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Semi-deterministic chemo-mechanical model of boundary lubrication2012Ingår i: Faraday discussions, ISSN 1359-6640, E-ISSN 1364-5498, Vol. 156, s. 343-360Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A model for tribofilm growth is developed. The model is used in combination with numerical contact mechanics tools to enable evaluation of the combined effects of chemistry and contact mechanics. The model is tuned with experimental data and is thereafter applied to rough surfaces. The growth of the tribofilm is evaluated for 3 different contact cases and short-term tribofilm growth behaviour is analyzed. The results show how tribofilms grow in patches. The model is expected to be used as a tool for analysis of the interaction between rough surfaces.

  • 44.
    Andersson, Martin
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Stocklassa, Jesper
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Klintberg, Lena
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Hjort, Klas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Control Systems For Gas-Expanded Liquids In Microreactors2017Konferensbidrag (Refereegranskat)
  • 45. Anthonis, Marc Henry
    et al.
    Bons, Anton-Jan
    Deckman, H. W.
    Hedlund, Jonas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Lai, Wenyih F.
    Peters, J.A.J.
    Crystalline molecular sieve layers and processes for their manufacture2000Patent (Övrig (populärvetenskap, debatt, mm))
    Abstract [en]

    A process is described for the manufacture of crystalline molecular sieve layers with good para-xylene over meta-xylene selectivity's good para-xylene permeances and selectivities. The process requires impregnation of the support prior to hydrothermal synthesis using the seeded method and may be undertaken with pre-impregnation masking. The crystalline molecular sieve layer has a selectivity (.alpha..sub.x) for para-xylene over meta-xylene of 2 or greater and a permeance (Q.sub.x) for para-xylene of 3.27.times.10.sup.-8 mole(px)/m.sup.2.s.Pa(px) or greater measured at a temperature of .gtoreq.250.degree. C. and an aromatic hydrocarbon partial pressure of .gtoreq.10.times.10.sup.3 Pa.

  • 46.
    Antzutkin, Oleg
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Kota, Hanumantha Rao
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Ikumapayi, Fatai
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Holmgren, Allan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Gunneriusson, Lars
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Johansson, Björn
    New Boliden AB.
    Berggren, Andreas
    New Boliden AB.
    Larsson, Anna-Carin
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Öberg, Sven
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Matematiska vetenskaper.
    Hedlund, Jonas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Mouzon, Johanne
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Bhuiyan, Iftekhar Uddin
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Forsmo, Seija
    LKAB.
    Interactions in multi-component mineral systems2011Konferensbidrag (Övrigt vetenskapligt)
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  • 47.
    Antzutkin, Oleg
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Kota, Hanumantha Rao
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Ikumapayi, Fatai
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Johansson, Björn
    New Boliden AB.
    Berggren, Andreas
    New Boliden AB.
    Larsson, Anna-Carin
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Holmgren, Allan
    Öberg, Sven
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Matematiska vetenskaper.
    Hedlund, Jonas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Mouzon, Johanne
    Bhuiyan, Iftekhar Uddin
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Forsmo, Seija
    LKAB.
    Interactions in multi-component mineral systems2010Konferensbidrag (Övrigt vetenskapligt)
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  • 48.
    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.

  • 49.
    Arango Munoz, Paty
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik.
    Stripper Modification of a Standard MEA Process for Heat Integration with a Pulp Mill2020Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    De 20 största massabruken i Sverige släpper tillsammans ut ungefär 20 miljoner ton CO2 per år. Dessa utsläpp har biogent ursprung och anses därför vara klimatneutrala. Massa- och pappersindustrin är därmed en lämplig kandidat för implementeringen av BECCS (eng. Bioenergy with Carbon Capture and Storage) och har en betydande potential att nå de, av den svenska regeringen, uppsatta klimatmålen som säger att Sverige inte ska några nettoutsläpp av växthusgaser till atmosfären senast år 2045. I detta examensarbete simulerades kemiska absorptions- och desorptionsprocesser med MEA som lösningsmedel genom att tillämpa den hastighetsbaserade metoden i en rigorös modell i Aspen Plus.

    Stripper- och absorptionsmodellerna validerades innan standardprocessen modifierades till en konfiguration som möjliggör värmeintegration av koldioxidinfångningens överskottsvärme med, exempelvis, ett sulfatmassabruk. Avskiljningsgraden och laddning hos den mättade lösningen användes som prestandaindikatorer för att validera absorptionskolonnerna. Återkokarens energiåtgång och laddning hos den omättade lösningen användes somprestandaindikatorer för att validera stripperkolonnerna. Samtliga kolonner dimensionerades för att erhålla 90 vikt% avskiljningsgrad. Olika flödeshastigheter av lösningsmedlet testades för att säkerställa effektivt nyttjande av packningen i absorptions- och stripperkolonnerna.

    Lämpliga temperaturnivåer för värmeintegration, inom och utanför, koldioxidinfångningen erhölls genom att utvärdera olika varianter av en stripper-overhead-kompression konfiguration. Utvärderingen av den modifierade MEA processen tog hänsyn till potentialen för ångbesparing och energieffektivisering. Resultat från simuleringarna tyder på att den modifierade strippern skulle kunna ge besparingar på upp emot 11 % i ånganvändning. Energibesparingar i samma storleksordning kunde även erhållas genom värmeintegration mellan koldioxidinfångningen och en särskild process i ett referensbruk. Implementering av BECCS-konceptet på det här sättet skulle därmed kunna bli ett mer attraktivt alternativ för den svenska massa- och pappersindustrin att bekämpa klimatförändringarna.

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  • 50.
    Argyropoulos, Dimitris D. S.
    et al.
    Departments of Chemistry and Forest Biomaterials, North Carolina State University, 431 Dan Allen Drive, Raleigh, North Carolina, 27695, USA.
    Crestini, Claudia
    Department of Molecular Sciences and Nanosystems, Ca' Foscari University of Venice, Via Torino 155, 30170, Venezia-Mestre, Italy.
    Dahlstrand, Christian
    Ren Fuel K2B AB, Rapsgatan 25, SE-754 50, Uppsala, Sweden.
    Furusjö, Erik
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap. Division of Bioeconomy and Health, RISE Research Institutes of Sweden, Lindholmspiren 7 A, SE-41756, Göteborg, Sweden.
    Gioia, Claudio
    Department of physics, University of Trento, Via Sommarive 14, 38123, Trento, Italy.
    Jedvert, Kerstin
    Division of Materials and Production, RISE Research Institutes of Sweden, Lindholmspiren 7 A, SE-41756, Göteborg, Sweden.
    Henriksson, Gunnar
    Wallenberg Wood Science Center (WWSC), KTH, Royal Institute of Technology, 100 44, Stockholm, Sweden.
    Hulteberg, Christian
    Department of Chemical Engineering, Faculty of Engineering, Lund University, 221 00, Lund, Sweden.
    Lawoko, Martin
    Wallenberg Wood Science Center (WWSC), KTH, Royal Institute of Technology, 100 44, Stockholm, Sweden.
    Pierrou, Clara
    RenFuel Materials AB, Rapsgatan 25, SE-754 50, Uppsala, Sweden.
    Samec, Joseph S. M.
    Ren Fuel K2B AB, Rapsgatan 25, SE-754 50, Uppsala, Sweden; RenFuel Materials AB, Rapsgatan 25, SE-754 50, Uppsala, Sweden; Department of Organic Chemistry, Stockholm University, Svante Arhenius väg 16 C, 10691, Stockholm, Sweden; Department of Chemistry, Faculty of Science, Chulalongkorn University, Pathumwan, 10330, Bangkok, Thailand.
    Subbotina, Elena
    Center for Green Chemistry and Green Engineering, Yale University, 370 Prospect St, New Haven, CT 06511, USA.
    Wallmo, Henrik
    Valmet AB, Regnbågsgatan 6, 41755, Göteborg, Sweden.
    Wimby, Martin
    Valmet AB, Regnbågsgatan 6, 41755, Göteborg, Sweden.
    Kraft Lignin: A Valuable, Sustainable Resource, Opportunities and Challenges2023Ingår i: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, artikel-id e202300492Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    Kraft lignin, a by-product from the production of pulp, is currently incinerated in the recovery boiler during the chemical recovery cycle, generating valuable bioenergy and recycling inorganic chemicals to the pulping process operation. Removing lignin from the black liquor or its gasification lowers the recovery boiler load enabling increased pulp production. During the past ten years, lignin separation technologies have emerged and the interest of the research community to valorize this underutilized resource has been invigorated. The aim of this Review is to give (1) a dedicated overview of the kraft process with a focus on the lignin, (2) an overview of applications that are being developed, and (3) a techno-economic and life cycle asseeements of value chains from black liquor to different products. Overall, it is anticipated that this effort will inspire further work for developing and using kraft lignin as a commodity raw material for new applications undeniably promoting pivotal global sustainability concerns.

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