El texto completo de este trabajo no está disponible en el Repositorio Académico UPC por restricciones de la casa editorial donde ha sido publicado. / The present work proposes a solution for the conditioning of bakery dough with the purpose of reducing costs by replacing manual work with a mechanized system that will be a piston extruder. In the process, the mass will be contained within a 304 stainless steel prismatic matrix with multiple outlet openings for optimization of the production line. The mechanical properties of bread dough were studied for the design of the platform and the estimation of the necessary compression force. A linear actuator was used, which exerts a compression force of 6 kN, which maximum linear speed is 5 mm/s. Validation of results will be carried out through simulated tests with a density mass of 1452.9 kg/m3. The system is composed of a linear actuator that performs the function of an extruder, followed by a pneumatic wire cutter. The process continues with a conveyor belt and ends with the injection of sesame seeds.The fundamental contribution is in the design of the extrusion chamber, since it allows the flow of the mass leaving minimal residue.

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Effective heat transfer through a bed of particulate solid largely affects the production rate and the process stability in an extrusion process. Most classical models in single screw extrusion treat the solids bed as a continuum behaving as an elastic plug or fluid while neglecting the discrete nature of the particles and the presences of the fluid. The heat transfer within the solids bed in these models is calculated based on thermophysical properties of the bulk system without consideration for the presence of the interstitial fluid. From a practical point of view, experimental measurements of solids bed heat transfer within a rotating screw, particularly cross channel, as the bed moves down the length of the solids conveying zone are impossible to perform. A new device was designed to model the radial compressive stresses and shear stresses on a solids bed of plastics, similar to the environment within the screw channel of a single screw extruder. This device enables the user to visualize the nature of the solids bed under different experimental conditions through a transparent wall. Also, the device provides ways to explore the heat transfer in a solids bed under different conditions by embedded thermocouples on the top or through the front wall of the containing chamber. The results reported in this study have shown that the discrete nature of the solid bed has a strong affect on the heat transfer within the bed. The rate of heat transfer within the different beds of polymer did not appear dominated by the thermophysical properties of the materials. Rather, the evidence supports that conduction through the pseudo-static interstitial fluid (i.e. air) dominated the rate at which a polymer bed heats up; a finding similarly found for the sintering of powdered metals and ceramics in the literature. This finding would imply that differences in melting rates found in extruders are not related to the heat transfer in the solids bed; however, this statement only holds true so long as the granules making up the bed remain static (i.e. plug-like) and do not circulate within the screw channel. Quite interestingly, pellet circulation within the solid bed was observed in LLDPE over a range of test conditions. This pellet circulation resulted in enhanced heat transfer within the bed of LLDPE (a raise of 10°C) compared to PS and PP. PP exhibited pellet circulation but only over a small window of operation. Different ways to improve heat transfer within solid bed were subsequently tested in this project, such as starve feed, forced convection and spherical particle. From this work, improved understanding of heat transfer in the solids conveying zone of a single screw extruder was gained. / Thesis / Master of Applied Science (MASc)

June 1st, 2014, the law on energy audits of large enterprises was introduces as a way of promoting energy efficiency and to help fulfil the demands from the EU energy efficiency directive. One company that this law applies to is Talent Plastics in Gothenburg. In 2017 an energy audit was conducted at the company by WSP in Karlstad. This audit has been used as a basis for this study. The purpose of this study has been to present solutions for reducing the energy use as Talent Plastics in Gothenburg. In this study, an energy balance for the facility has been modelled. This model has then been used in order to evaluate some of the different solutions presented in the previous energy audit as well as some new solutions that have been identified. The solutions that have been studied are: Heat recovery from the process cooling by installing a heating battery in ventilation systemsHeat recovery from the process cooling by pre-heating ventilation airUpdating old extruder machinesHeat recovery from the compressed air systemUsing outside air for the compressed air systemUpdate of the existing heat recovery system installed in the production ventilation system Based on the results presented in this report the system today is inefficient with a large need for heat whilst a lot of energy is cooled through process cooling. The energy balance presented showed a higher use of energy for heating of ventilation air compared to the results presented in the previous energy audit. This is a consequence of the assumptions made when conducting an energy audit. By underestimating the energy need for the heating of ventilation air, the potential energy savings from solutions including heat recovery in the ventilation systems has been underestimated. Out of the solutions investigated in this study, updating the heat recovery system in the ventilation system for production spaces resulted in the largest energy savings with savings of 192 MWh per year. The maximum energy savings using heat recovery from the process cooling were 202 MWh/year. This solution had a pay-off time of 0,7 years. The results showed that heat recovery from the compressed air system is not a suitable solution for the facility. When combining different solutions updating the existing heat recovery system installed in the production ventilation system combined with pre-heating and installation of a heating battery in the same ventilation system would result in energy savings of 323 MWh per year. This represents 14 % of the total energy use for the facility and savings of 226 thousand Swedish krona per year.

Granulation is an important process for industries ranging from plastics to food and pharmaceutics. In the last decades, the twin-screw extruder has been more and more studied as a continuous method for granulation. But there are many questions remaining to be answered such as the functions of kneading block and the granulation behavior in this zone, the influence of the wetting method, and also the influence of the active pharmaceutical ingredient (API) properties on the granulation process. Therefore, in this project, a series of experiments were performed based on a new technique to the granulation field named ‘screw pullout’ for understanding the granulation process within the twin-screw extruder. In order to understand the specific function of an important screw element known as a kneading block, the physical particle motion reflecting progress of granulation was monitored along the screw. Different feed rate and formulations were studied; the residence time and pressure in kneading block were measured; and the granules along the screw were characterized for their porosity and size distribution. It was found that granule consolidation and breakup within the kneading block allowed the production of granules with consistent properties and excellent mechanical strength. However, the changes produced by a kneading block are dependent upon the formulation. For example, the kneading block demonstrates no observable function with formulations containing a significant content of microcrystalline cellulose. The most notable benefit of the kneading block to all tested materials appeared to be distribution of the interstitial binding liquid rather than to compact the powders. A new wetting method using a foam binder has been studied intensively in this work to assess its influence on the granulation process. A series of studies have been performed to compare the granule development along the screws as powder formulation and screw design were varied to test for the differences induced by the two wetting methods (foam delivery or liquid injection). The evolution of the granules along the screw was characterized by analyzing the particles size distribution, porosity, and fracture strength. It was found that the wetting method had minor impact on the particle size distribution due to the strong mechanical dispersion inherent to the extruder. The major finding for the pharmaceutical industry was that the foam method reduces the required amount of liquid to granulate, thereby dropping drying time after the process. The foamed binder was also found to be preferred when the formulation contains powder components with poor spreading properties. Finally, the influence of an API’s physical properties on granulation was studied by comparing formulations with varying API hydrophobicity. It was found that the API and binder distribution was not affected by the hydrophilicity of API, while the particle size distribution, porosity and fracture strength were strongly dependent on the properties of the API. / Thesis / Master of Applied Science (MASc)

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Yes / It has been shown that seeded granules of calcium carbonate can be produced in commercial batch high shear granulators such as the Cyclomix high-shear impact mixer. Seeded granules are attractive to the pharmaceutical industry due to their high uniformity and good mechanical properties which can assist efficient tablet manufacture. In the current study, attempts to produce seeded granules of Durcal 65 and PEG 4000 binder using hot melt granulation are reported, in response to the recent shift towards continuous pharmaceutical manufacturing. Various screw configurations and rotation speeds were investigated in a series of experiments to determine the relationship between process conditions and granule properties. Particle size analysis, strength measurement and structural characterisation were used to quantify granule properties. It was found that using a series of kneading elements arranged at a 60° staggering angle located near to the feed section of the extruder screw generated strong, spherical granules. From structural characterisation approximately 5–15% of extruded granules were found to be seeded. Twin screw melt granulation is therefore considered to be a promising technique for continuous production of seeded granules, although a more detailed investigation is required to optimise yield and quality.

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Solvent-free extrusion emulsification (SFEE) is a novel emulsification technology that operates without solvent to produce sub-micron sized particles (100–200 nm) using a twin-screw extruder (TSE) with high viscosity polymers (up to 600 Pa.s has been tested to date) and only water as the liquid medium. Surfactants have always been known to play a key role in the success of the SFEE process, however very little work has been done to investigate the mechanisms by which they operate, along with isolating the region of the process to which they play the most vital role. The first part of this thesis focused on an investigation into how different surface-active properties impacted the mechanism of SFEE. Three ionic (SDBS, Unicid 350, Calfax DB-45) and three non-ionic surfactants (Igepal CO-890, Brij 58, Synperonic F-108), each with differing surface-active properties were tested in solvent emulsification (SE) prior to their evaluation in SFEE. Synperonic F-108 was the only surfactant found unsuccessful in the SE process, and was therefore disregarded prior to SFEE testing. Of the three ionic surfactants, SDBS and Calfax were the only ones found to successfully create a stable emulsion in SFEE; the latter species doing so with 50% reduced molar loading. Igepal and Brij were found to produce very low amounts of emulsified material (5-25% of the total solids mass), requiring molar loadings that greatly exceed those of SDBS and Calfax to do so. Particles generated by both SE and SFEE were tested at extreme operating conditions to compare their relative stabilities, and were found to experience similar stability behaviours. This result reinforces previous findings that the dispersion stage controls the SFEE technique. The second part of this thesis continued the investigation on the use of non-ionics in SFEE, with a focus on the impact of their molecular structure on the overall process. Non-ionic surfactants with varying hydrophilic end group chain lengths were tested in SFEE, and it was determined that the optimal hydrophilic chain length was between 10–12 ethoxy units, where shorter chains resulted in coarse particle generation. The structure of the hydrophobic end group was tested as well, and through experimentation it was determined that a branched end group structure was slightly more beneficial than a linear end group to emulsion stabilization. As seen in the first part of this thesis, none of the new selection of non-ionic surfactants were capable of inducing sufficient phase inversion to result in a high percentage of emulsion leaving the extruder. The most promising ionic surfactant, Calfax DB-45, was combined with various promising non-ionic surfactants to create binary surfactant mixtures, and were tested in SFEE. Initial results yielded the most promising blend as Calfax/Igepal CA-630. After manipulation of both molar ratio and total surfactant loading, it was determined that a minimum Calfax loading of 0.06 mmol/g resin was required in the blend to achieve a stable 100 – 200 nm emulsion in both SE and SFEE processes, regardless of non-ionic concentration. The benefits of adding a non-ionic surfactant in the blend were seen with the substantial reduction of Calfax entrapped in the final latex particles, apparent by the distinct decrease in overall particle charge. A mini-study examining the impacts of increasing the viscosity of the water phase by hydrocolloid addition for the dilution stage has shown that positive changes to emulsion properties can be seen by this approach, but further experimentation is required before concrete conclusions can be made. / Thesis / Master of Applied Science (MASc) / The creation of nanoparticles has been a growing area of research in recent years, with numerous different means of generation being developed. Extruders have seldom been used for the generation of nanoparticles due to issues related to controlling generated particle characteristics. Previous work has shown that twin-screw extruders are capable of generating 100–200 nm particles, but the process has shown minimal robustness to variations in operating conditions. The aim of this study has been to continue the work of nanoparticle generation within a twin-screw extruder, with a specific focus on the impacts that special soap-like particles (surfactants) have on the process. Surfactants are special particles consisting of both a hydrophilic (“water-loving”) and hydrophobic (“water-hating”) end group that allows multiple substances to combine on a chemical level. Variations in the molecular structure and electronic charge of these surfactants, along with blends of different types of surfactants have been tested to gain a better understanding of their role in the process, and hopefully increase the overall robustness of the process. Overall, it was determined that surfactants with a negative charge were more successful in creating polyester latex particles than ones with a neutral molecular structure. The blending of a charged and neutral surfactant has been shown in this study to not only be successful in generating particles of desired size, but have also shown the ability to reduce the overall charge of the final latex particles.