doktorska disertacija
Marko Tramšek (Author), Andreja Goršek (Mentor), Đurđa Vasić-Rački (Co-mentor)

Abstract

Povečano povpraševanje po kefirnih zrnih, kot ključne komponente v mnogih komercionalno-vizionarskih industrijskih aplikacijah, bodisi v živilskem ali biokemijskem sektorju, zahteva izboljšanje obstoječih diskontinuirnih in hkrati intenzivni razvoj novih ekonomsko učinkovitih kontinuirnih obratov njihove proizvodnje s povečano kapaciteto. Pri tem so ključnega pomena tehnološke inovacije na področju reaktorskih sistemov proizvodnje kefirnih zrn. V doktorski disertaciji smo podrobneje obravnavali inovativno načrtovanje kontinuirnih reaktorskih sistemov tradicionalne proizvodnje kefirnih zrn z gojenjem v mleku. Osrednji cilj disertacije je bil določiti optimalne volumne reaktorjev v eno-, dvo- ali več-stopenjskih kontinuirnih reaktorskih sistemih. V ta namen smo razvili nove kompleksne matematične izraze in problem nelinearnega programiranja (NLP) za ocenjevanje optimalnih volumnov reaktorjev pri različnih presnovah glede na pH vrednost fermentacijskega medija in kapacitetah proizvodnje kefirnih zrn. Med eno-stopenjskimi reaktorskimi sistemi smo analizirali pretočno mešalni reaktor(PMR) in cevni reaktor (CR). Pri dvo- oz. več-stopenjskih sistemih smo obravnavali kaskade PMR in CR, dveh PMR ter N-tih PMR. Prav tako smo v disertaciji razvili in validirali t. i. tri-dimenzionalni napovedni (TDN) model, ki podaja eksplicitno matematično formulacijo za izračun optimalnega volumna j-tega reaktorja v kaskadi N-tih PMR. TDN model predstavlja učinkovitoin hkrati uporabniku prijazno alternativno tehnološko orodje, saj poenostavlja kompleksni nelinearni problem ocenjevanja optimalnih volumnov PMRv različnih reaktorskih sistemih. Na omenjeno tematiko disertacije do sedajni bilo znanstvenih objav, zato smo predlagali nov pristop k razvoju reaktorskih sistemov proizvodnje kefirnih zrn, ki temelji na t. i. strukturirani in eksperimentalno podprti metodologiji načrtovanja. Gre za celovit sklop uporabe kombinacije rezultatov preliminarne raziskave in modeliranja rastne krivulje pri razvoju novih modelov oz. metod ocenjevanja optimalnih volumnov kontinuirnih reaktorjev, ki upoštevajo edinstvene karakteristike kefirnih zrn. Tako v širšem kontekstu doktorska disertacija obravnava tudi eksperimentalno optimiranje procesnih parametrov šaržnega gojenja kefirnih zrn v mleku, izboljšanje postopka aktivacije kefirnih zrn, statistično primerjavo različnih primarnih napovednih modelov rasti klasično ter optimalno aktiviranih kefirnih zrn, ipd. Doktorska disertacija je nedvomno samostojni izvirni znanstveni prispevek na področju bioreakcijske tehnike, saj obravnava najzahtevnejše vidike na znanju temelječega načrtovanja kompleksnih reaktorskih sistemov. Hkrati v globalnem merilu predstavlja pomemben korak k izboljšanju obstoječih oz. razvoju novih kontinuirnih obratov proizvodnje kefirnih zrn.

Keywords

kefirna zrna;proizvodnja;rastna krivulja;optimiranje;modeliranje;načrtovanje reaktorjev;

Data

Language: Slovenian
Year of publishing:
Typology: 2.08 - Doctoral Dissertation
Organization: UM FKKT - Faculty of Chemistry and Chemical Engineering
Publisher: [M. Tramšek]
UDC: 541.127:66.098(043.2)
COBISS: 242657792 Link will open in a new window
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Other data

Secondary language: English
Secondary title: Design of continuous reactor systems for kefir grains production
Secondary abstract: Increased demand on kefir grains, as key component in many commerciallyvisional industrial applications, either in food or biochemical processing, requires improvement of existent batch and simultaneously intensive development of new economically efficient continuous grains production plants with higher capacity. Accordingly, the technological innovations on the field of reactor systems for kefir grains production are the key issue. This doctoral dissertation describes an innovative design of continuous reactor systems for traditional kefir grains production with cultivation in milk. The main goal of the dissertation was to determine the optimal volumes of reactors in one-, twoor multi-stage reactor systems. For this purpose a new complex mathematical expressions and non-linear programming(NLP) problem for estimating the optimal volumes of reactors at different conversions with regard to pH value of fermentation media and kefir grains production capacities have been developed. Among one-stage reactor systems, the continuously stirred tank reactor (CSTR) and plug flow reactor (PFR) have been analyzed. Moreover, among two- or multi-stage systems, the cascades of CSTR and PFR, two CSTRs and N CSTRs have been examined. In doctoral dissertation, a so-called threedimensional predictive (TDP) model, presenting explicit mathematical formulation for calculating the optimal volume of j-th reactor in cascade of N CSTRs, has also been developed and validated. TDP model simplifies the complex non-linear problem of estimating the optimal CSTRs volumes in different reactor systems and therefore presents efficient and simultaneously user friendly alternative technological tool. Up to date, no scientific studies concerning the dissertation topic have been published. Therefore, the new approach for development of reactor systems for kefir grains production, which is based on so-called structured and experimentally supported design methodology, has been proposed. Summarily, thenew models or methods for estimating the optimal volumes of continuous reactors, which consider unique kefir grains characteristics, have been developed by integrated usage of results of preliminary research and growth curve modeling. Consequently, in extended context the doctoral dissertation also includes experimental optimization of process parameters of batch kefir grains cultivation in milk, improvement of kefir grains activation procedure, statistical comparison between predictive growth models of classically and optimally activated kefir grains, etc. The present doctoral dissertation dealswith the most demanding aspects of knowledge based complex reactor systemdesign and therefore, it is undoubtedly individual original scientific contribution on the field of bioreaction engineering. Consequently, the work presents globally important step toward improvement of existent and development of new continuous kefir grains production plants.
Secondary keywords: kefir grains;production;growth curve;optimization;modeling;reactors design;
URN: URN:SI:UM:
Type (COBISS): Dissertation
Thesis comment: Univ. v Mariboru, Fak. za kemijo in kemijsko tehnologijo
Pages: XXII, 143 str.
ID: 8715534