<p>This work focuses on the physical properties and crystallization of theophyline co-crystals. Co-crystals of theophylline with oxalic acid, glutaric acid and maleic acid have been investigated.</p><p>The DSC curves of these co-crystals show that their first endothermic peaks are all lower than the melting temperature of theophylline. The decomposition temperature of theophylline – oxalic acid co-crystal is at about 230 °C, determined by DSC together with TGA. After decomposition, the remaining theophylline melts at about 279 °C, which is higher than the known melting temperature of theophylline, suggesting a structure difference, ie. a new polymorph may have been formed. The formation of hydrogen bonds in theophylline – oxalic acid co-crystal was investigated by FTIR. Changes of FTIR peaks around 3120 cm^-1 reflects the hydrogen bond of basic N of theophylline and hydroxyl H of oxalic acid. The solubility of theophylline – oxalic acid co-crystal and theophylline – glutaric acid co-crystal was determined in 4:1 chlroform – methanol and in pure chloroform respectively. At equilibrium with the solid theophylline – oxalic acid co-crystal, the theophylline concentration is only 60 % of the corresponding value for the pure solid theophylline. At equilibrium with the solid theophylline – glutaric acid co-crystal, the theophylline concentration is at least 5 times higher than the corresponding value for the pure solid theophylline. Two phases of theophylline were found during the solubility determination. In the chloroform – methanol mixture (4:1 in volume ratio) the solubility of the stable polymorph of theophylline is found to be about 14 % lower than that of the metastable phase. Various aspects of the phase diagram of theophylline – oxalic acid co-crystal was explored.</p><p>Theophylline – oxalic acid co-crystal has been successfully prepared via primary nucleation from a stoichiometric solution mixture of the two components in chloroform – methanol mixture. By slurry conversion crystallization, the co-crystal can be prepared in several solvents, and yield and productivity can be significantly increased. Theophylline – glutaric acid can be successfully prepared via both co-grinding of the two components and slow evaporation with seeding.</p> / QC20100608

During this master thesis, the possibility of ammonia removal from digestate in combination with after hygienization has been investigated. The aim of the work was to see how much ammonia that could be removed but also the properties of other process parameters such as TS/VS content, pH and alkalinity of the digestate. It was also of interest to study the energy balances for a process that combines ammonia stripping with after hygienization. The purpose of hygienization in a biogas plant is to kill pathogens. To study ammonia stripping combined with after hygienization, a prototype of an ammonia stripper was built in a laboratory. The digestate was heated to the hygienization temperature of 70 °C and air was led through with the help of a peristaltic pump by the end of the system. Condensate was trapped in a bottle by cooling the tube and the gases were brought to another bottle containing 1 M sulfuric acid. Ammonia and sulfuric acid reacted and formed ammonium sulfate. The process was also tested with closed system using vacuum to decrease the boiling point and thereby create more condensate. The results from the experiments showed that with an air stripping process most of the ammonium was trapped in the sulfuric acid while with a vacuum process more ammonium was trapped in the condensate. The most important parameters to achieve a good ammonia removal were air flow and time. With the vacuum system, more condensate was removed. The removal of condensate could make it possible to recirculate process fluid from the stripping process and thereby save energy in the centrifugation part which is used to create a solid part of the bio digestate. It was concluded from the experiments that air stripping is more effective when it comes to ammonium recovery. The process could be improved by using higher air flow which could decrease the time to less than one hour, which is the desired hygienization time. However, it is desired to keep the pump flow as low as possible since it is energy consuming. A chemical increase of the pH would also be of interest to try since previous tests showed a strong correlation between high pH-value and good ammonia stripping. More tests overall are of interest to ensure a reliable result. Still, the combination of after-hygienization and ammonia stripping would contribute to a better environment and a sustainable agriculture with a natural and nutritious digestate.

Luossavaara-Kiirunavaara AB (LKAB) rullar järnmalmslig till råkulor, som sedan bränns till pellets. Råkulorna bildas i rullkretsar som består av rulltrummor och rullsiktar. Under 2017 färdigställdes en pilotskaleanläggning för kulrullning i LKAB:s Agglomeringslaboratorium i Malmberget. Syftet med anläggningen är att prediktera dynamiken i en storskalig rullkrets, under olika betingelser. Detta examensarbete är ett första försök att i forskningssyfte studera gensvaret i LKAB:s pilotrullkrets. Syftet var att undersöka om pilotrullkretsen kan prediktera dynamiken och råkulekvalitet i rullning i storskaliga rullkretsar och målet var att fastställa ett effektivt körsätt. Kulrullning är inom LKAB:s kärnkompetens och därför har reagensursprung och karaktär samt dimensionering av rullkretsen lagts med sekretess. Kodnamn används både för sliger och reagens. Arbetet inleddes med att skapa ett körschema med målet att så många olika blandningar som möjligt kunde köras i pilotrullkretsen under en normal arbetsdag. Fem olika blandningar kunde köras. Fyra olika tillsatser testades: bentonit, ett flotationsreagens (FLOT), ett organiskt bindemedel (OB) och en ny utvecklingsprodukt (UTV). Första körningen i pilotrullkretsen var med varierande doseringar av bentonit eftersom dess inverkan i kulrullning är välkänt hos LKAB. Försök två och tre, med FLOT respektive OB, kunde jämföras mot tidigare erfarenhet från storskaliga försök. Det fjärde och sista försöket var ett test hur pilotrullkretsen predikterade utvecklingsprodukten UTV. Varje typ av försök utfördes två gånger. Pilotrullkretsen predikterade väl både dynamik och råkulekvalitet i alla de tre försöken där erfarenhet från storskaliga körningar var tillgängligt. Den nya, okända, UTV-produkten visade en förbättrad råkulekvalitet, utan att dynamiken i kretsen påverkades negativt. UTV kan därför vara ett intressant alternativ för ett framtida storskaligt försök hos LKAB. Det framtagna körschemat fungerade mycket väl. Ett ”grundanalyspaket” har skapats för att underlätta planering och genomförande för framtida pilotrullkretsförsök hos LKAB. Antalet personer som behövs vid rullkretskörningar beror på antalet blandningar och analyser. Vid enklare körningar behövs minst fem personer, utöver försöksledaren. Mer komplexa körningar kan kräva sju personer. / Luossavaara-Kiirunavaara AB (LKAB) produce pellets from magnetite iron ore. Pellets are formed by balling moist iron ore concentrate to green pellets, which are then burned to pellets. The green pellets are formed in balling circuits consisting of balling drums and roller decks for screening. In 2017 a pilot scale balling circuit with a drum was completed in LKAB's agglomeration laboratory in Malmberget. The purpose of the pilot balling circuit is to predict the dynamics in a full scale balling circuit under different conditions. This master degree project is an initial attempt to study the response in LKAB's pilot circuit in terms of green pellet quality and dynamics in the circuit. The goal was to determine an effective way to run experiments and to investigate whether the pilot circuit can predict the dynamics of balling in large-scale circuits. Pelletizing production is within LKAB's core competence, and therefore the origin and character of the reagents, as well as the design of the pilot balling drum circuit, are confidential. Code names are used for both iron ore concentrates and reagents. The work began by creating a test procedure with the aim of running as many different mixtures as possible in the pilot balling circuit during a normal working day. Five different mixtures could be run. Four different additives were tested: bentonite, a flotation reagent (FLOT), an organic binder (OB) and a new development product (UTV). The first experiment in the pilot balling circuit was run with varying doses of bentonite because its impact in balling is well known at LKAB. Experiment two and three, with FLOT and OB, could be compared to previous experience from large scale test runs. The fourth and last experiment was a test of how the pilot circuit predicted the behavior of a new development product UTV. Each type of experiment was performed twice. The pilot balling circle predicted well both dynamics and green pellet quality in all three experiments where experience from large-scale runs was available. The new, unknown, UTV product showed improved green pellet quality, without affecting adversely on the dynamics of the circuit. UTV can therefore be an interesting option for a future large scale run at LKAB. The developed working schedule worked very well. A "basic analysis package" has been created to facilitate planning of future experiments in the pilot balling circuit. The number of persons needed to run the circuit depends on the number of mixtures and analyzes. For smaller experiments, at least five people is required, in addition to the leader of the experiments. More advanced experiments will demand seven people.

One of the main interests in commercial methane production is to maximize the gas yield, and it is thus appealing to use material with relative high methane potential. However, such material often results in process instability whereas ammonia inhibition is common. Removal of ammonia through adsorption is a fairly unexplored method in the field of biogas production, and could prove to be cost-effective.The adsorption capacity of pulp fibres from the paper making industry were investigated through batch adsorption experiments. Additionally, the fibres effect on small scale batch digesters in terms of methane production and cellulase activity was explored. Overall, the adsorption capacity of the pulp fibres was low, whereas Kraft hardwood had the highest adsorption capacity in both an aqueous ammonium solution and digester fluid at 11±3 and 60±20 mg g-1, respectively. The initial total ammonium nitrogen concentration had the highest effect on the adsorption capacity with a positive correlation. The pulp fibres seemingly had no effect on the ammonia inhibited anaerobic digestion systems. However, the cellulase activity was higher after day 5 in the anaerobic digestion systems with a high ammonia concentration.In essence, the overall results showed that the adsorption of the fibres was relatively low and most likely not suitable as a material to prevent ammonia inhibition in an AD.

This report details the development and validation of a model for the simulation of supported liquid membrane processes, as applied to the extraction of lanthanides. Supported liquid membranes are systems where two phases, usually aqueous, are separated by a third phase, typically organic, which acts as a membrane, in order to separate solutes from one phase to the other. The model employs an analytical solution to the diffusion equation for the organic phase and linear approximations of the resistances to mass transfer in the aqueous phase boundary layers. The goal of this model is to underline the importance of taking these boundary layer resistances into account. / Detta arbete introducerar, deriverar och evaluerar en matematisk modell för simulering av vätskemembranprocesser, tillämpat på vätskeextraktion av lantanider. Immobiliserade vätskemembran betecknar system där två faser oftast vatten, separeras av en tredje organisk fas som agerar membran för att separera och transportera lösta komponenter från den ena vattenfasen till den andra. Modellen utnyttjar sig av en analytisk lösning till diffusionsekvationen för den organiska fasen och linjära approximationer för motstånden mot masstransport i de båda vattenfasernas gränsskikt. Målet med modellen är att understryka vikten av att inkludera dessa gränsskikt i beräkningarna.

The basic ingredient of paper is the individual wood fibers. The property of the fibers depends on a variety of factors e.g., method of pulp production and processing. The final sheet quality depends in part on how the fibers interface between each other and therefore factors that affect the fiber size are of interest. The flexibility of the fibers depends in part on the pore water i.e., the fiber swelling. The sheet becomes less flexible at low water content which gives a loss in strength. Thus it becomes desirable to increase the water uptake. The experimental investigation described in this report consists of exposing the wood fibers to different ions and ionic strength and then measure the pore size by thermoporosimetry where a DSC (Differential Scanning Calorimeter) is used. DSC measures the freezing point of water in the pores of the wood fibers. As the freezing point varies with the pore size the size distribution can be determined. The results show that there are complications with thermoporosimetry measurements at different ion concentrations. The strength of the ionic solutions will contribute to a fictitious pore volume, which makes analysis difficult to interpret.

Solvents play a crucial role in the Active Pharmaceutical Ingredient (API) manufacturing and are used in large quantities. Most of the industries incinerate the waste solvents or send it to waste management companies for destruction to avoid waste handling and cross-contamination. It is not a cost effective method and also hazardous to the environment. This study has been performed at AstraZeneca’s API manufacturing plant at Sodertalje, Sweden. In order to find a solution, a solvent recovery system is modeled and simulated using ASPEN plus and ASPEN batch modeler. The waste streams were selected based on the quantity and cost of the solvents present in them. The solvent mixture in the first waste stream was toluene-methanol in which toluene was the key-solvent whereas in the second waste stream, isooctane-ethyl acetate was the solvent mixture in which isooctane was the key-solvent. The solvents in the waste stream were making an azeotrope and hence it was difficult to separate them using conventional distillation techniques. Liquid-Liquid Extraction with water as a solvent followed by batch distillation was used for the first waste stream and Pressure Swing Distillation was used for the second waste stream. The design was optimized based on cost analysis and was successful to deliver 96.1% toluene recovery with 99.5% purity and 83.6% isooctane recovery with 99% purity. The purity of the solvents was decided based on the quality conventions used at AstraZeneca so that it can be recovered and recycled in the same system. The results were favorable with a benefit of €335,000 per year and preventing nearly one ton per year carbon dioxide emissions to the environment. A theoretical study for the recovery system of toluene-methanol mixture was performed. The proposed design was an integration of pervaporation to the batch distillation. A blend of polyurethane / poly(dimethylsiloxane) (PU / PDMS) membrane was selected for the separation of methanol and toluene mixture. The results of preliminary calculations show 91.4% toluene recovery and 72% methanol recovery with desired purity.

The knowledge of kinetics of pyrolysis is important. It is also challenging to find parameters for kinetic which can be applied at different sizes of biomass. Many researchers have been investigating the pyrolysis behavior of wood powders due to heat and mass transfer limitations. They have also been focusing on determining the effects of feedstock characterization, residence time, gas environment, heating rate and the final temperature as well as the arrangement of the pyrolysis reactor and modeling of the kinetics. This project presents a qualitative understanding of the pyrolysis process based on data from slow heating rates. Samples of spruce chips at different masses, namely 4 mg, 200 mg, 500 mg and 800 mg and also 4 mg powder have been used in experiments with thermogravimetric analysis to understand the mass loss behavior. Furthermore, kinetic parameters for biomass are taken from literature and have been used in modeling to understand to which extent these parameters are different for different particle sizes. The kinetic model that is chosen to investigate in this project is where each component of biomass shows different characteristics during the thermal decomposition. The experimental results on wood chips at different sample masses show same behavior for all of them and there is no heat and mass transfer limitations. The results from experiments on powders shows different behavior than for chips at the end of the mass loss curve only. This means less char is produced for powders than it is for the chips. The results from modeling show that kinetic parameters such as activation energy and the prefactor are the same for both powders and chips. The only parameter that is different is the pre-determined char yield for hemicellulose second reaction. The kinetic model and the kinetic parameters used in this report are in good agreement to the experimental results. The model used, where each component show different behavior during its thermal decomposition and the final products are volatiles and char is a reliable model to describe the mass loss behavior of biomass. The difference in the experimental results between powders and chips can be explained by the modeling. It can be stated that the difference is in the char yield from thermal decomposition of hemicellulose. / Kunskap om kinetiken för pyrolysprocessen är viktig. Det är även en utmaning att finna parametrar för kinetiken som kan tillämpas till olika massor och storlekar av biomassa. Många forskare har undersökt pyrolys beteenden på bara träpulver på grund av värme- och massöverföring begränsningar. De har också fokuserat på att undersöka effekterna av råvara karakterisering, uppehållstid, gasmiljö, uppvärmningshastighet och den slutliga temperaturen samt arrangemanget av pyrolysreaktorn och modellering av kinetiken. I detta projekt presenteras en kvalitativ förståelse av pyrolysprocessen baserad på data från långsamma uppvärmningshastigheter. Prover av granflis vid olika massor; 4 mg, 200 mg, 500 mg och 800 mg och även 4 mg pulver har använts i experimenten med thermogravimetric analys för att förstå massförlust uppträdandet. Dessutom har kinetiska parametrar för biomassa tagits från litteratur och har använts i modelleringen för att förstå i vilken utsträckning dessa parametrar skiljer sig åt för pulver och flis. Den kinetiska modellen som har valts att undersökas i detta projekt är den där varje komponent av biomassa visar separata och olika egenskaper under termisk nedbrytning. De experimentella resultat på flis vid olika provmassorna uppvisar samma beteende för dem alla och det finns ingen värme- och massöverföringsbegränsningar. Resultaten från experiment på pulver visar annorluna beteende än för träflis endast i slutet av massförlust kurvan. Detta innebär att mindre kol produceras för pulver än vad det gör för flis. Resultaten från modelleringen visar att kinetiska parametrar såsom aktiveringsenergin och prefactor är densamma för båda pulver och flis. Den enda parameter som skiljer sig är den förutbestämda utbytet av kol för hemicellulosa’s andra reaktion. Den kinetiska modellen och kinetiska parametrar som används i denna rapport är i god överensstämmelse med de experimentella resultaten. Denna modell som används, där varje komponent visar enskilt beteende under dess termisk nedbrytning och slutprodukterna är bara gaser och kol, är en pålitlig modell för att beskriva beteendet för massförlust av biomassa. Skillnaden i de experimentella resultaten mellan pulver och flis kan förklaras av modelleringen. Det kan konstateras att skillnaden är i kol utbytet från sönderdelningen av hemicellulosa.

This work investigates the fluid flow in a cylindrical millilitre vial stirred by a magnetic stirred bar using Computational Fluid Dynamic (CFD). Stirred millilitre vials are used to study nucleation phenomena and crystallization as an outline of literature study of nucleation and crystallization phenomena and the role of stirring in this process. The baffle free vial was meshed with around 500,000 cells. To simulate the stirring a rotary frame and moving walls were used. Stirring speeds were between 100 and 1000 rpm where considered, correspondently to a stirrer Reynolds number between 260 and 2600. For stirring speeds bellow 500 rpm, simulations by both the both laminar flow model and the k-ε model where run, while above 500 rpm only k-ε was used. Results of the two models were very similar indicative the adequacy of k-ε to simulate the flow even at low Reynolds. The flow shows expected circulation pattern with upwards pumping close to side walls and downwards pumping in the centre of cylindrical vial. At 1000 rpm circulation patterns expands up to the top of the vial while at 300 rpm and lower the upper half of the vial is poorly mixed. The average turbulent energy of the flow is very low comparing with the squared stirrer tip speed and the power number decrees with Reynolds number, indicating that the flow is not fully turbulent.

Cement production is responsible for around 7% of the global anthropogenic carbon dioxide emissions. More than half of these emissions are due to the unavoidable release of carbon dioxide upon thermal decomposition of the main raw material limestone. Many different options for carbon capture are currently being investigated to lower emissions, and one potential route to facilitate carbon capture could be the implementation of an electrified separate calcination step. However, potential effects on the phase composition of cement clinker need to be investigated, which is the aim of the present study. Phases of special interest are alite, belite, aluminate, ferrite, calcite, and lime.  The phase composition during clinker formation was examined through HT-XRD lab-scale experiments, allowing the phase transformations to be observed in situ. Two different methods of separate calcination were investigated, one method in which the raw meal was calcined separately, and one method where the limestone was calcined separately. The former yielded an alite amount similar to that of the reference experiments, whereas the latter method yielded a lower amount. It could, unfortunately, not be excluded that the difference was due to poor experimental conditions, and additional experiments are needed to investigate the matter further. The study does, however, indicate that a calcined raw meal might be used to produce a clinker of similar phase composition concerning major phases belite, aluminate, ferrite, alite, and free lime. A raw meal containing calcined limestone might, however, need longer residence time at clinkering temperature too obtain similar phase composition. In addition, a raw meal containing calcined limestone was observed to be carbonated to a greater extent upon reheating than a calcined raw meal. Further experiments are needed to fully understand the effects on clinker composition of an electrified separate calcination step, and several improvements to the experimental method are given in the study.