20.500.12556/RUL-175174 Razvoj in karakterizacija ejektorskega sistema za generiranje mikromehurčkov za intenzifikacijo karbonizacije Development and characterization of an ejector system for microbubble generation for the intensification of carbonation Intenzifikacija procesa karbonizacije, pri katerem se CO$_2$ absorbira v alkalno raztopino, predstavlja obetavno smer za zajem in uporabo ogljika. Glavna omejitev procesa je počasen prenos snovi zaradi nizke topnosti plina in majhne medfazne površine. Namen magistrske naloge je bil razviti in karakterizirati eksperimentalni ejektorski sistem za generiranje gostih disperzij mikromehurčkov, ki povečajo medfazno površino in s tem omogočajo pospešen prenos snovi. Eksperimentalna postavitev je temeljila na ejektorju Carmin D2, brizgalni črpalki in PDMS mikrokanalu. Sistem smo ovrednotili glede na vpliv volumskega pretoka (1000–3000 μL/min) in koncentracije neionskega surfaktanta Tween 20 (0–20 ppm) na velikost, porazdelitev, stabilnost in gostoto mehurčkov. Za kvantitativno analizo smo razvili avtomatiziran protokol v programu ImageJ z dvema specializiranima makro kodama. Rezultati so pokazali, da povečanje pretoka poveča velikost mehurčkov in njihovo gostoto do 155 mehurčkov/mm$^2$. Dodatek surfaktanta je imel ključen vpliv, že 10 ppm Tween 20 je povečalo število stabiliziranih mehurčkov na stene mikrokanala pri najvišjem pretoku za faktor 4,6 (iz 129 na 594) in omogočil površinsko pokritost do 10 %. Časovna analiza je potrdila, da surfaktant učinkovito preprečuje koalescenco, medtem ko Ostwaldovo zorenje ostaja glavni mehanizem destabilizacije. Zaključimo lahko, da razviti ejektorski sistem zanesljivo generira goste disperzije mikromehurčkov v mikrokanalu ter dosega visoko specifično medfazno površino. Sistem izkazuje velik potencial za intenzifikacijo procesov, kjer je prenos snovi omejujoč korak, npr. pri karbonizaciji in predstavlja trdno osnovo za nadaljnje aplikativne raziskave. Intensification of the carbonation process, in which CO$_2$ is absorbed into an alkaline solution, represents a promising pathway for carbon capture and utilization. The main limitation of this process is the slow mass transfer caused by the low solubility of CO2 and limited interfacial area. The aim of this thesis was to develop and characterize an experimental ejector-based system capable of generating dense dispersions of microbubbles, thereby significantly increasing the interfacial area and enabling accelerated mass transfer. The experimental setup was based on Carmin D2 ejector, a syringe pump, and a PDMS microchannel. The system was characterized by studying the effects of volumetric flow rate (1000–3000 μL/min) and the concentration of the nonionic surfactant Tween 20 (0-20 ppm) on bubble size, distribution, stability and density. For quantitative analysis, an automated protocol with two specialized macro codes was developed in ImageJ. The results showed that increasing flow rate increased bubble size and their density up to 155 bubbles/mm$^2$. The addition of surfactant had a decisive effect, at only 10 ppm Tween 20, the number of stabilized bubbles at the highest flow rate increased by a factor of 4,6 (from 129 to 594) enabling surface coverage of up to 10 %. Time-resolved analysis confirmed that the surfactant effectively prevents coalescence, while Ostwald ripening remains the main destabilization mechanism. In conclusion, the developed ejector-based system reliably generates dense microbubble dispersions in a microchannel and achieves a high specific interfacial area. The system shows strong potential for the intensification of the processes where mass transfer is the limiting step, such as carbonation, and provides a solid basis for further application-oriented research. mikromehurčki ejektorski sistem intenzifikacija procesa microbubbles ejector system process intensification true false false Slovenski jezik Angleški jezik Magistrsko delo/naloga 2025-10-20 12:15:02 2025-10-20 12:15:14 2025-12-07 03:46:49 0000-00-00 00:00:00 2025 0 0 0000-00-00 NiDoloceno NiDoloceno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 25461 259124995 Kozjek_Blaz_-_Intenzifikacija_procesa_karbonizacije.pdf Kozjek_Blaz_-_Intenzifikacija_procesa_karbonizacije.pdf 1 A16D8BCC5F9C86D9C71A4D6E554F74CC 3d1d35fa60018ef3835dd8c015073ca9d5a60f32ba9e46872a225c5b92b9f427 640881fd-ad9d-11f0-9328-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=220482 Fakulteta za kemijo in kemijsko tehnologijo 0 0 0