P2-0032 — Annual report 2009
1.
Mathematical modelling of ethanol production by mixed kefir grains yeast population as a function of temperature variations

A mathematical model was developed to describe the effect of temperature and fermentation time on the kinetic parameters of ethanol production by the mixed kefir grains yeast population. Modified Gompertz model was used to describe this phenomenon. The kinetic parametersl were predicted by using the least-square method. The influence of temperature on kefir grains biomass increase and microbiological composition of kefir product and kefir grains quantified. Furthermore, Arrhenius relationship between operating temperature and the maximum ethanol production rate was established.

COBISS.SI-ID: 13630486
2.
MODEL FOR SIMULTANEOUS EVALUATION OF DIFFERENT STRATEGIES FOR THE CO-PRODUCTION OF BIOETHANOL AND BEET SUGAR

The purpose of this study was to examine the contribution that mathematical modeling with mixed integer non-linear programming can offer to any decision-making about different co-production strategies for sugar and bioethanol, according to changing market situations. An optimization-based conceptual process design that relies on superstructure optimization was used to simultaneously search for an economically and environmentally-optimal strategy for co-producing sugar and bioethanol.

COBISS.SI-ID: 13399318
3.
Comparison between nitrate and pesticide removal from ground water using adsorbents and NF and RO membranes

An investigation was carried out regarding the removal of pollutants such as nitrate and pesticides (atrazine, deethylatrazine and deisopropylatrazine) from actual ground water samples obtained in Slovenia, by the use of two new adsorption resins, one derived from styrenedivinylbenzene and one from polystyrene, and commercial nanofiltration and reverse osmosis membranes. Atrazine and deethylatrazine were also bound to the activated carbon. Despite the different technologies applied, the effort was directed towards simultaneous removal of the above-mentioned pollutants.

COBISS.SI-ID: 13221910
4.
Translation of variables and implementation of efficient logic-based techniques in the MINLP process synthesizer MIPSYN.

For solving very complex combinatorial systems we developed alternative Generalized Disjunctive Programming (GDP) formulation and convex hull representations for process synthesis problems and their implementation in a unique mixed-integer nonlinear programming (MINLP) process synthesizer MIPSYN. The initial research indicates that the proposed alternative convex hull representation usually outperforms the conventional one when solving both nonlinear (NLP) and mixed-integer linear programming (MILP) [COBISS 13415702].

COBISS.SI-ID: 13415702
5.
MINLP synthesis of processes for the production of biogas from organic and animal waste

This paper describes a superstructure approach for the synthesis of biogas processes simultaneously with the selection of different process background alternatives. An aggregated mathematical model with an economic objective function was developed. The optimal solution of an industrial case study, applied to an existing large-scale meat company, indicates that significant benefit can be obtained if biogas processes are selected simultaneously with the selection of different process background alternatives.

COBISS.SI-ID: 13787414