Određivanje interakcijskih parametara u vodenim dvofaznim sustavima

master's thesis

• Title (english): Determination of interaction parameters in aqueous two-phase systems
• Author: Leonard Bauer
• Mentor: Marko Rogošić (mentor)
• Committee member: Marko Rogošić (predsjednik povjerenstva)
• Committee member: Bruno Zelić (član povjerenstva)
• Committee member: Šime Ukić (član povjerenstva)
• Granter: University of Zagreb; Faculty of Chemical Engineering and Technology; Zagreb
• Defense date and country: 2016-09-28, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Chemical Engineering; Mechanical, Thermal and Separation Processes

Abstract

U radu je prikazan postupak modeliranja ravnoteže u vodenom dvofaznom sustavu voda – polietilenglikol – (NH4)2SO4 pri atmosferskom tlaku i temperaturi 25 °C. Na temelju literaturnih podataka istražena je primjenjivost modela koeficijenta aktivnosti NRTL modificiranog prema Wu i suradnicima, modificiranog Pitzerovog virijalnog modela te empirijskog modela dobivenog kombiniranjem Merchukove jednadžbe za opis binodalne krivulje s Othmer-Tobiasovim izrazom za nagib veznih linija. Posebna pažnja usmjerena je na odabir i primjenu optimizacijskih algoritama – rješenje genetskog algoritma korišteno je kao inicijacija za egzaktne optimizacijske algoritme: algoritam po Nelder-Meadu, odnosno po Levenberg-Marquardtu. Uz postojanje odstupanja modela od eksperimentalnih podataka, modificirani Pitzerov virijalni model pokazao se prikladnijim za opis ravnoteže kapljevina-kapljevina od modificiranog modela NRTL . Modificirani Pitzerov virijalni model pokazao se prikladniji i prilikom predviđanja ravnoteže sustava ovisno o molekulskoj masi polimera. Empirijski model eksperimentalne podatke opisuje točnije od teorijskih modela, ali za razliku od njih nema mogućnost predviđanja faznog ponašanja u uvjetima koji se razlikuju od onih pri kojima su prikupljeni eksperimentalni podaci.

Abstract (english)

This thesis presents the procedure of modelling liquid-liquid equilibrium in the aqueous two-phase system water – polyethylene glycol – (NH4)2SO4 at atmospheric pressure and temperature of 25 °C. Based on literature data, the applicability of NRTL activity coefficient model modified by Wu and collaborators, modified Pitzer virial model and empirical model formed by combining Merchuk expresion for binodal curve and Othmer-Tobias tie line correlation were tested. Special attention was paid to choosing and applying optimisation algorithms – the solution of genetic algorithm was used as an initiation for exact optimisation algorithms of Nelder-Mead's and Levenberg-Marquardt. Considering the difference between calculated and experimental data, modified Pitzer virial model appeared to be more suitable for describing liquid-liquid equilibrium than modified NRTL model. Modified Pitzer virial model also appeared to be more suitable for predicting the equilibrium of the systems dependence on polymer molecular weight. Empirical model describes the experimental data more acurately than teoretical models but lacks the ability to predict the phase behaviour in conditions different than the ones used in the experiments.

• Keywords: ravnoteža kapljevina-kapljevina; vodeni dvofazni sustav; genetski algoritam; polietilenglikol; modificirani model NRTL; modificirani Pitzerov model; model po Merchuk-Othmer-Tobiasu
• Keywords (english): liquid-liquid equilibria; aqueous two-phase systems; genetic algorithm; polyethylene glycol; modified NRTL model; modified Pitzer model; Merchuk-Othmer-Tobias model
• Language: croatian
• URN:NBN: urn:nbn:hr:149:450763
• Study programme: Title: Chemical Engineering - Graduate study; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka kemijskog inženjerstva (magistar/magistra inženjer/inženjerka kemijskog inženjerstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2017-11-24 07:30:19