Title Priprava i karakterizacija nanofluida na osnovi biodizela Title (english) Preparation and characterisation of biodiesel based nanofluids Author Leona Komparić Mentor Ante Jukić (mentor)Committee member Ante Jukić (predsjednik povjerenstva)Committee member Fabio Faraguna (član povjerenstva)Committee member Marin Kovačić (član povjerenstva)Granter University of Zagreb Defense date and country 2022-09-19, Croatia Scientific / art field, TECHNICAL SCIENCES Abstract Cilj ovog rada je priprava i karakterizacija nanofluida sačinjenih od baznih fluida podrijetlom iz obnovljivih sirovina, odnosno biomase. U tu svrhu pripravljene su suspenzije višestjenčanih ugljikovih nanocijevi (MWCNT) u biodizelu i repičinom ulju kao baznim fluidima. Biodizel je fluid manje viskoznosti nego što je to repičino ulje, stoga je provedena usporedbena analiza svojstava pripravljenih nanofluida. Provedba eksperimenata podijeljena je u dvije faze. U prvoj fazi sintetiziran je biodizel iz repičinog ulja i izobutanola reakcijom transesterifikacije. Karakterizacija biodizela provedena je pomoću FTIR-a i 1H NMR-a. Druga faza podrazumijeva pripravu i karakterizaciju nanofluida. Nanofluidi su pripravljeni ultrazvučnom homogenizacijom različitih koncentracija MWCNT raspona 0,10 mas. % - 2,50 mas. % u repičinom ulju i biodizelu. Provedeno je ispitivanje stabilnosti, toplinske vodljivosti, reoloških svojstava i mazivosti. Dobiveni rezultati pokazuju dobru stabilnost obje vrste nanofluida pod utjecajem gravitacijske sile. Međutim, pod utjecajem centrifugalne sile, rezultati pokazuju bolju stabilnost nanofluida na osnovi repičinog ulja u odnosu na nanofluid na osnovi biodizela. Dodatak nanočestica povećava toplinsku vodljivost baznog fluida. Vrijednosti toplinske vodljivosti niže su za biodizel kao bazni fluid, nadalje, za nanofluide na osnovi biodizela zabilježen je veći porast toplinske vodljivosti u odnosu na nanofluide na bazi repičinog ulja. Eksperiment pokazuje da je repičino ulje otprilike 6,5 puta viskozniji fluid od biodizela. Dodatkom nanočestica povećava se viskoznost fluida te je primijećen veći porast viskoznosti za nanofluide na osnovi repičinog ulja uspoređujući iste koncentracije MWCNT u nanofluidu. Ispitivanjem reoloških svojstva pokazano je odstupanje od Newtonskog ponašanja dodatkom nanočestica. Veće odustupanje od Newtonskog ponašanja pokazuje fluid na osnovi repičinog ulja. Ispitivanjem mazivosti pokazano je najveće smanjenje koeficijenta trenja za nanofluid na osnovi biodizela s koncentracijom MWCNT nanočestica od 0,10 mas. %.
Abstract (english) The aim of this work is preparation and characterization of nanofluids based on base fluids originating from renewable raw materials, i.e., biomass. For this purpose, suspensions of multi wall carbon nanotubes (MWCNT) were prepared in biodiesel and rapeseed oil as base fluids. Biodiesel is fluid with lower viscosity than rapeseed oil, therefore a comparative analysis of the prepared nanofluids is conducted. The implementation of the experiment was divided into two phases. In the first phase, biodiesel was synthesized from rapeseed oil and isobutanol through a transesterification process. Characterization of biodiesel was conducted using FTIR and 1H NMR. The second phase involves the preparation and characterization of nanofluids. Nanofluids were prepared using ultrasonic homogenization of different concentrations of MWCNTs in the range 0.10 wt. % - 2.50 wt. % in rapeseed oil and biodiesel. Stability, thermal conductivity, rheological properties and lubricity were investigated. The obtained results show good stability of both types of nanofluids under the influence of gravitational force. However, under the influence of centrifugal force, the results show better stability of rapeseed oil based nanofluid compared to biodiesel based nanofluid. The addition of nanoparticles increases the thermal conductivity of the base fluid. Thermal conductivity values are lower for biodiesel as a base fluid, and also a greater increase in thermal conductivity was recorded for the biodiesel based nanofluids than the rapeseed oil based nanofluids. The experiment proves that rapeseed oil is about 6,5 times more viscous fluid than biodiesel. The addition of nanoparticles increases the viscosity of the fluid, and a greater increase in viscosity was observed for the rapeseed based nanofluid compared to the same concentrations of MWCNTs in nanofluid. By examining the rheological properties, a deviation from the Newtonian behaviour was shown by the addition of nanoparticles. A larger deviation from Newtonian behaviour is shown by the rapeseed oil based fluid. The lubricity test showed the greatest reduction in the friction coefficient for the biodiesel based nanofluid with MWCNT concentration 0.10 wt. %.
Keywords
nanofluid
biodizel
repičino ulje
MWCNT
toplinska svojstva
reološka svojstva
Keywords (english)
nanofluid
biodiesel
rapeseed oil
MWCNT
thermal properties
rheological properties
Language croatian URN:NBN urn:nbn:hr:149:630531 Study programme Title: Applied Chemistry - Undergraduate study; specializations in: Environmental chemistry and green technologies, Advanced materials and technologies, Applied organic chemistry Type of resource Text File origin Born digital Access conditions Open access Terms of use Created on 2023-03-01 13:34:40
