Research activity


Research field of Laboratory for Process Systems Engineering and Sustainable Development is developing and using the advanced Process Systems Engineering methods for designing sustainable manufacturing technologies for chemicals and energy production, transition from fossil fuels and petroleum-based feedstocks to the renewable sources, closing the water and CO2 cycles, improving mass and energy efficiencies, developing new materials and products, reaction and bioreaction engineering, environmental protection and sustainable development. The Laboratory develops innovative approaches for simultaneous solving of multi-level structure of production systems, i.e. from the atoms and molecules over the individual processes up to the local and global supply chains for products and energy. In order to achieve these goals, the Laboratory develops multi-level design strategies connecting the construction of the technology systems’ optimization with laboratory and pilot experiments for generation of certain input data and models validation. With close connection between mathematical modelling and experimental research laboratory masters the complex process systems and develops paths for using basic knowledge for solving practical problems. The investigations are performed at different levels:

Synthesis of the entire (bio)chemical supply chains

In this part of the work we have worked with Professor Ignacio E. Grossmann from Carnegie Mellon University, USA, with Professor Jiří J. Klemeš and Professor Petar S. Varbanov from University of Pannonia, Veszprém, Hungary, and with Dr Mariano Martín from University of Salamanca, Spain. We have upgraded the developed generic synthesis mixed-integer linear programming (MILP) model for optimisation of the regional networks for production and consumption of energy, food, and chemical products from biomass, within the entire production network. The regional network consists of four layers: production of resources (L1), collection, pre-processing and storage (L2), processing into products, biorefineries and energy plants (L3), and the usage of products (L4). The model have been further upgraded into multi-period model, which accounts for seasonality of raw materials and their prices, intermediate storage of raw materials and products, degradation of raw materials and products over the storage period, the optimal harvesting period, optimal selection of areas during the year for year-round biomass resources (e.g., algae), and optimal selection of raw materials, such as waste cooking oil. This model also includes Total Site heat integration, accounting for heat losses during distribution and the cost of the heat-distribution network.

Increasing use of renewable resources

An optimisation model for the simultaneous synthesis of a biogas process and heat exchanger network was developed. The model was applied within the process of biogas production in an existing large-scale meat processing industry Perutnina Ptuj. The result of optimisation is an energy self-sufficient thermophilic process of biogas production from animal manure and plant biomass with a closed water circuit and a simple heat exchanger network arrangement. We have developed a method for integrating solar thermal energy within the processes that require heating, and the methodology for maximising the usage of renewable energy sources in terms of their variable availability.

Synthesis of new (bio)reaction paths, bio- and biopharmaceutical processes

The influence of fermentation temperature, agitation rate, and additions of carbon sources,vitamins and minerals on production of kefiran by kefir grains lactic acid bacteria was studied.The main aim of the work was to increase the specific exopolysaccharideproduction It was proved that the controlling of culturing conditions and the modifying of fermentation medium conditions can dramatically enhance its production. The temperature,agitation rate and addition of carbon sources were critical for kefiran production. IGrain growth is not proportional to kefiran contents.

Monoesterification of diols is of considerable practical interest. The resulting products are widely used for cosmetical, pharmaceutical and nutritional purposes.Monoesterifications are known as reversible reactions, for which kinetics and mechanisms are difficult to determine.  The ethylene glycol monoesterification with benzoic acid in an automated reaction calorimeter equipped with an on-line IR spectrometer was studied.  Based on the observed IR spectra, product concentration profiles were constructed. Using the obtained kinetic and stoichiometric data, the reaction mechanism was established which explains the observed reaction characteristics.

The rigorous kinetic model for the reaction rate and mass transfer coefficient estimation was developed. Using this model is vital due to evolution of the interfacial properties and solubility during the reaction. As a consequence the kinetics of mass transfer and the global rate of the chemical conversion can be modified. Based on the proposed methodology the kinetics of our reaction was defined very precisely. Sodium benzoate synthesis was used as a case study. Based on dynamic simulation we developed the mass transfer area and overall mass transfer coefficient profiles during the reaction.

The conversionsof alcohols to aldehydes or ketones are one of the mostimportant transformations within organic chemistry. Theyare especially useful as building-blocks during pharmaceutical syntheses. Because very little kinetic information on these reactions has been disclosed to date, menthol oxidation reaction was analysed under isothermal conditions.  Menthol has a low solubility in water; therefore acetone was added to the diluted sulphuric acid as a co-solvent. Reaction media becomes more homogeneous and thus more appropriate for kinetic analyses without considering a mass transfer term.With increased homogeneity we accelerated the rate of reaction.

Environmental impact reduction

A methodology for comprehensive sustainable development assessment within the breweries was developed based on the benchmarking analysis. This methodology was applied to bi-objective optimization of an industrial water network. The proposed solutions demonstrate minimal consumption and cost of freshwater. Besides, their competitiveness regarding the similar plants within particular industrial branch and BAT technologies was evaluated.

The life cycle assessment (LCA) was accomplished within the utility company in order to reduce the construction and demolition waste. The origin, type and amount of waste were examined. Those parts of the system with the most significant environmental impact have been identified in order to reduce the environmental impacts and costs.

An overview of the economic, environmental and social footprints (or indicators) was made that can be used for measuring the progress of a particular system towards sustainable development. We have also reviewed the tools with which it is possible to evaluate the footprints or sustainable development by considering several criteria. Carbon and nitrogen footprints have been evaluated for biomass-based energy production, where it was found that carbon footprint was reduced in comparison with the fossil-based energy. On the other hand, the nitrogen footprint was significantly increased in comparison with the natural gas, fuel oil and also coal. The potential of carbon, nitrogen and water footprints reduction has been evaluated, and presented in the locally integrated energy sector which is based on the Total Site methodology.

Composite indicators that combine several subindicators into one index are frequently used for sustainable development assessment. Different methods of normalization, weighting, and aggregation of subindicators were tested on an industrial case study. Their advantages and drawbacks were discussed in order to propose the best scheme for calculating the composite sustainability index.

Additionally, we have developed three methods for sustainable development assessment, suitable for multi-criteria optimisation: the method of total sustainability indexes, the method of total footprints, and the method of the eco- and total profits. The commonly-used methods of sustainability indexes, such as the footprints and eco-costs, have been upgraded so that in addition to direct burdening effects, they include also indirect unburdening effects, related to the usage and substitution of environmentally-harmful products. Multi-objective optimisation therefore gives priority to alternative solutions that besides the economic efficiency unburden the environment the most, and then to solutions that burden the environment the least, which represents the new perspective on system design. We have developed a methodology for reducing a large number of criteria within multi-criteria optimisation to a smaller number of representative criteria. This method has been presented on the case of environmental footprints so far.

Further, we have developed a model for the synthesis of heat exchanger networks by considering the trends in energy pricing for the entire lifetime. The results of this kind of synthesis are heat exchanger networks with reduced energy consumption in comparison with the synthesis where only the current energy prices were used.

New production procedures, tools and technologies – systems technology EWO

According to the principles of cleaner production and sustainable products we update and change the existing processes to make the environment more sustainable. Any available energy within the separate processes is transferred to the processes where energy is required. Consequently, we focused on the energy demanding processes which were integrated. The utilities were saved on this way. Industrial waste water can be utilized with recycling to subsystems for steam and electricity cogeneration.

Computer applications, solution methods and strategies – synthesizer MIPSYN

A two-step multiobjective approach for the superstructural synthesis of sustainable chemical processes by means of mathematical programming was developed. The first step includes the usual economy-based optimization of the superstructure containing various technological alternatives. In the second step, the superstructure is extended by the sustainable alternatives, and bi-criteria optimization is performed by using the economic and environmental criteria. It was established that solutions could be obtained which are improved in both, often conflicting criteria.

Knowledge and technologies transfer

The know-how and optimization tools developed have been applied to designing and optimizing the plant for metal surface protection, and the process for waste oil-in-water emulsions treatment. We continued with the participation in the European project VCSE (Virtual Campus for Sustainable Europe).
We also started to transfer our knowledge about e-learning and e-teaching into the primary school level. The emphasis was on the creation of the bank of questions that teachers can use for the student’s assessment of knowledge. The usability of interactive, multimedia e-materials, which were made by ourselves was ascertained at different courses.


  • Software for Computer Aided Process Engineering: Aspen+, HYSYS, SuperPro Designer, SuperTarget, PHAST, DIPPR
  • Optimization Software: GAMS, MIPSYN-MINLP, ICAS, Interfaces
  • Math Software: MathCad, MATLAB, Mathematica, Polymath
  • Liquid phase chemical reactor Armfield
  • Tubular flow reactor Armfield
  • AvtomReaction Calorimeter RC1 Mettler Toledo
  • Spectrophotometer ReactIR IC10
  • AnaerAnaerobic and aerobic reactors Armfield
  • CCEU catalytic reactor Armfield
  • Corrosion study kit Armfield
  • Aeration unit
  • Process Control Teaching System Armfield
  • RSST reactive system screening tool
  • Safety Testing Equipment MP-1, MP-4 Kühner
  • Laboratory of ecological technology
  • Membrane Bioreactor ZW-10 Zenon
  • Reverse Osmosis Unit Culligan
  • Ozone generator Wedeco
  • Flocculation system for JAR – test
  • EasyMax automatic two reactors system


Research Programme Group

P2 – 032: Process System Engineering And Sustainable Development
Pricipal Researcher:Zdravko Kravanja


Projekt L2-0358 (2008-2011): Synthesis and recontruction of processes on the basis of alternative renewed sources for green energy production
Pricipal Researcher:Zdravko Kravanja

Projekt L2-3645 (2010-2013): Sustainable optimization of integrated bio-refineries
Principal Researcher: Peter Glavič


How could logistics and the safety of the transport of chemicals be improved in the Mediterranian area, LOSAMEDCHEM, Europe in the Mediterranean. 2010–2013. Ref. no. 2G-MED09-199.
Coordinator: Peter Glavič

European Training Partnership on Sustainable Innovation, TRUST IN.2010–2013.Leonardo da Vinci – Partnerships. Ref. no. LDV-PAR-48/10.
Coordinator: Peter Glavič

Operational programme Slovenia-Hungary 2007-2013.Ref. No. SI-HU-2-2-012.
Coordinator: Damjan Krajnc

Znanje za gospodarstvo v mejni regiji – KBB




MINLP Synthesis of Processes Based on Alternative Renewable Resources
Pricipal Researcher: Zdravko Kravanja

Bosnia and Herzegovina

Development and application of an optimization model for the reduction of water consumption in process industries
NoPrincipal Researcher: Zdravko Kravanja

Republic of South Afric

Competitive Programme for Rated Researchers 2012, collaboration with Prof. Duncan Frazer, University of Cape town
Pricipal Researcher at UM: Zdravko Kravanja