Thermodynamic characterization of multicomponent mixtures of esters and alcohols at atmospheric and elevated temperatures and pressures
Termodinamička karakterizacija višekomponentnih smeša estara i alkohola na atmosferskim i uslovima povišenih temperatura i pritisaka
Doktorand
Aissa, Mohamed Ahmed M.Mentor
Kijevčanin, MirjanaČlanovi komisije
Radović, IvonaIvaniš, Gorica
Živković, Nikola
Metapodaci
Prikaz svih podataka o disertacijiSažetak
Biofuels have attracted considerable attention for current and future utilization because of their
benefits as promising alternative, ecological and economical viable fuels, with particular reference
to biodiesel and alcohols. In order to use biodiesel in diesel engines, the volumetric and transport
properties of the fuel (i.e. density and viscosity) must be improved since they affect spray
properties, atomization and combustion processes of a fuel. In addition, the derived thermodynamic
magnitudes, such as isothermal coefficient and isobaric thermal expansion coefficient, greatly
influence the atomization process and, consequently, the fuel consumption of diesel engines.
Therefore, knowledge of these properties at different pressures and temperatures is important in
order to predict and improve the performance of diesel engines. Densities, viscosities, sound
velocities and refractive indices of pure components: 1-butanol, 1-propanol, ethyl laurate, ethyl
linoleate, ethyl myristate, et...hyl oleate, methyl laurate and n-hexadecane were measured at
temperatures T= (293.15 to 343.15) K and atmospheric pressure. The measured values were
compared to several available literature data, and good agreement was noticed: an overall absolute
average percentage deviation (AAD) of 0.04%, 0.07%, 3 % and 0.1% for density, speed of sound,
viscosity and refractive index data, respectively.
Besides that, densities, viscosities, speeds of sound and refractive indices of ternary mixture ethyl
oleate + n-hexadecane + 1-butanol (3), and for the corresponding binary mixtures: ethyl laurate + 1-
propanol, ethyl oleate + 1-butanol, ethyl oleate + 1-propanol, ethyl oleate + n-hexadecane, nhexadecane + 1-butanol and n-hexadecane + 1-propanol were measured in the temperature range T=
(293.15 to 343.15) K at atmospheric pressure. The measurements were performed on an Anton Paar
DSA 5000 M density and sound velocity meter, Anton Paar SVM 3000 digital viscometer, and
Anton Paar RXA 156 refractometer. From the experimental data, a number of thermodynamic
parameters were also calculated, namely, excess molar volumes (VE), viscosity deviation functions
(∆), deviations in refractive index (∆nD), excess molar Gibbs energy of activation of viscous flow
(∆G*E) and deviation in isentropic compressibility (∆κs). The binary and ternary properties are then
correlated as a function of the mole fraction by using the Redlich–Kister and Nagata and Tamura
equations, respectively, and then used to analyze molecular interactions present in the mixtures...
Biogoriva su privukla značajnu paţnju, kako za trenutnu, tako i za buduću upotrebu zahvaljujući
svojim prednostima kao obećavajućim alternativnim, ekološkim i ekonomičnim gorivima, a posebno
se ističu biodizel i bioalkoholi. Da bi se biodizel koristio u dizel motorima moraju mu se poboljšati
volumetrijska i transportna svojstva (tj. gustina i viskoznost), jer utiču na raspršivanje, atomizaciju i
sagorevanje goriva. Pored toga, izvedene termodinamičke veličine, kao što su izotermska stišljivost
i izobarni koeficijent termičkog širenja, značajno utiču na proces atomizacije, a samim tim i na
potrošnju goriva u dizel motorima. Stoga je poznavanje ovih svojstava pod različitim pritiscima i
temperaturama vaţno kako bi se predvideo i poboljšao rad dizel motora. Gustine, viskoznosti,
brzine zvuka i indeksi refrakcije čistih komponenti: 1-butanola, 1-propanola, n-heksadekana, etil
oleaat, etil linoleata, etil laurata, etil miristata i metil laurata su mereni na temperaturama T =
(293,15 do 34...3,15 ) K pri atmosferskom pritisku. Izmerena vrednosti su poreĎene sa nekoliko
dostupnih literaturnih podataka, I primećeno je dobro slaganje, ukupno prosečno pocentualno
odstupanje (AAD) je bilo oko 0,04%, 0,07%, 3% i 0,1%, redom za gustine, brzine zvuka,
viskoznosti i indekse refrakcije.
Pored toga, merene su i gustine, viskoznosti, brzine zvuka i indeksi refrakcije ternerne smeše etil
oleat + n-heksadekan + 1-butanol , i odgovarajućih binarnih smeša etil oleat + 1-butanol, etil oleat +
1-propanol, etil oleat + n-heksadekan, etil laure + 1-propanol, n-heksadekan + 1-butanol i nheksadekan + 1-propanol u temperaturnom opsegu T = (293,15 do 343,15) K sna atmosferskom
pritisku. Merenja su izvršena na Anton Paar DSA 5000 M ureĎaju za merenje gustine i brzine
zvuka, Anton Paar SVM 3000 digitalnom viskozimetru i Anton Paar RKSA 156 refraktometru. Iz
eksperimentalnih podataka su, takoĎe, izračunai I brojni termodinamički paramtetri, kao na pr.
Dopunska molarna zapremina (VE), odstupanje viskoznosti (∆), odstupanje indeksa refrakcije
(∆nD), dopunska molarna Gibsova energija aktivacije viskoznog toka (∆G*E) i višak izentropske
kompresibilnosti (∆κs). Binarna i ternarna svojstva su nakon toga korelisana u zavisnosti od
molekulskih sastava primenom Redlih-Kister i Nagata i Tamura jednačina, redom, a potom su
korištena za analizu molekulskih interakcija unutar smeša...