BUDAPEST UNIVERSITY OF TECHNOLOGY AND ECONOMICS
FACULTY OF CHEMICAL ENGINEERING
DEPARTMENT OF
CHEMICAL ENGINEERING AND PROCESSING
Head of department:
Zsolt Fonyo
D.Sc, Full professor, member of the Hungarian Academy of Sciences
Address:
Department of
Chemical Engineering and Processing
Budapest University of Technology and Economics
XI. Mûegyetem rkp. 3., KMf.56.
H1521 BUDAPEST,
Hungary
Phone: (+361) 463 2202
Fax: (+361) 463 3197
BUDAPEST
2003
SCOPE
The responsibility of the Department of Chemical Unit Operations and Process Engineering is to teach and train for chemical engineering students the following basic chemical engineering subjects:
The Department was founded in 1952. The previous heads of department were Prof. Gy. Sárkány, Prof. M.G. Yefimow, Prof. K. Tettamanti, Prof. P. Földes, Prof. J. Manczinger.
Since 1994, the current head of department is Professor Zsolt Fonyó.
The most important research fields of the department are
ACADEMIC STAFF
telephone
name number highest degrees and titles
+36 1 463 xxxx
FONYÓ, Zsolt 3196 DSc., Professor, Head of Department
BORUS, Andor 2174 DT., Senior lecturer
DEÁK, András 1490 PhD., Associate Professor
HAVAS, Géza 1490 CSc., Associate Professor
HUNEK, József 3199 DT, Senior lecturer
KEMÉNY, Sándor 2209 DSc, Professor
LELKES Zoltán 2209 PhD, Senior lecturer
MANCZINGER, József 3199 CSc, Professor
MIZSEY, Péter 2174 DSc., Professor
RÉV, Endre 1189 CSc., Associate professor
REZESSY, Gábor 2035 DT., Senior lecturer
SAWINSKY, János 3199 CSc, Titled professor
SIMÁNDI, BÉLA 1490 PhD., Associate Professor
SZÉKELY, Edit 2209 PhD, Senior lecturer
DSc: Doctor of Science, granted by Hungarian Academy of Sciences
PhD, PhD degree
CSc: Candidate of Science, granted by Hungarian Academy of Sciences, appr.: PhD
DT: Doctor Technicus, granted by Technical University of Budapest
EDUCATION
Chemical Unit Operations courses constitute the central activity of the education in the Department. CUO I to III and Process Control courses are compulsory for all the chemical and biochemical engineer students. Most of the other courses are compulsory for the education branch Process Systems Engineering, almost all of them are compulsory in the education branch Chemical Management, and all of them are also alternative courses for other students. Most of the courses are also presented in English, and some of them in German, for foreign language students.
One lecture is 45 minutes presentation. One semester consists of 15 active weeks. Thus 45 lectures for a course means 3 times 45 minutes lecture time weekly. The length of the laboratory practices and room exercises are also measured in these units.
The courses are numbered as Enn below. Capital letters B and P at the end of a course name denotes courses for Bioengineering Section (B) and Process Engineering Branch (P), respectively. Courses without such letters belong to either the main Chem. Eng. Section, or to its Proc. Eng. Branch, or both.
Education staff 20032004
Course number 
Course sign 
LecturerConductor (main section) 
Colecturer(s) foreign language section 
E1.1 
CUOI 
Fonyó 
Havas, Sawinsky 
E1.2 
CUOII 
Fonyó 
Havas, Sawinsky 
E1.3 
CUOIII 
Sawinsky 
Deák, Simándi 
E1.4B 
CUOIV.B 
Sawinsky 
Deák, Simándi 
E1.4P 
CUOIV.P 
Sawinsky 
Deák 
E1.5B 
CUOV.B 
Sawinsky 

E1.5P 
CUOV.P 
Kemény 

E2.1 
PC 
Mizsey 
Borus 
E2.2 
CPCI 
Mizsey 

E2.3 
CPCII 
Mizsey 

E3.1 
PDMI 
Rév 

E3.2 
PDMII 
Rév 

E3.3 
PDMCS 
Rév, Mizsey 

E4 
Opt 
Lelkes 

E5 
DAE 
Kemény 

E6 
CPD 
Mizsey 

E7 
CPE 
Rév 

E8 
PT 
Rév 

E9 
EPCI 
Mizsey 

E10 
LLSLE 
Simándi 

E11 
MCCP 
Lelkes 

E12 
EPE 
Fonyó 
Mizsey 
E13 
EBPD 
Fonyó 
Mizsey 
All the colleagues take part in conducting seminars and laboratory practices.
MAIN COURSES
E1. Chemical Unit Operations
E1.1. Chemical Unit Operations I (45 lectures)
(Hydrodynamic Unit Operations, Heat Transfer Operations)
Related room exercises: 30 units
Unit Operations of Chemical Engineering. Continuity equations, mass balance, component balance, energy equation, momentum balance, equations of motions, transport equations, equations of state, equilibrium, chemical kinetics. Fluid mechanics, concepts of fluid behaviour, steady flow, rheology, viscosity, boundarylayer formation, friction factor. NavierStokes, Euler and Bernoulli equations. Transportation of fluids. Hydrodynamic models, flow in pipes and channels, pressure flow through equipment, pressure drop across packed towers.
Mechanical unit operations: mixing, sedimentation: thickeners, filtration. Electrical and magnetic methods, centrifugal separation, fluidization, pneumatic transport, gas cleaning: cyclones. Flow of heat, conduction, convection, radiation. Rate of heat transfer, heating and cooling: viscosity correlation. Dimensional analysis. Heat transfer of condensation, steady and unsteadystate heat transfer. Heat transfer in shell and tube heat exchangers. Evaporation, boiling point rise. Standard and multipleeffect evaporators, vapour compression.
E1.2. Chemical Unit Operations II (45 lectures)
(Mass Transfer Unit Operations)
Related pilot plant laboratory exercises: 60 units
Principles of mass transfer, equilibria, material balances for stagecontact plants and differentialcontact plants, theory of diffusion. Theoretical stage concept, transfer unit concept. Column and stage efficiencies. Gas absorption, design of packed towers. Distillation methods: flash distillation, differential and steam distillation, rectification. Design and operating of plate columns. Azeotropic, extractive and reactive distillation. Fractionating devices. Extraction and leaching, crystallisation. Airwatercontact operations and drying. New and hybrid separation methods. Basic theory of process design: synthesis and analysis, economic, environmental, operational and energy considerations.
Laboratory practice with pilotscale apparatus (evaporators, heat exchangers, mixers, filters, gas absorption, distillation, rectification, extraction etc.).
E1.3. Chemical Unit Operations III (45 lectures)
(Reaction Engineering)
Related room exercises: 15 units
Related pilot plant laboratory exercises: 45 units
Macromixing and residence time distribution in continuos flow reactors. Experimental determination of the residence time distribution. Flow models for axial dispersion and backmixing. Influence of micromixing on conversion. Degree of micromixing in stirred tank reactors. Multiphase reactors. The role of mass transfer in fluidfluid reaction systems. Heterogeneous reactions at an external surface and in porous solids. Influence of mass transfer on selectivity. Similarity between the Hatta number and the Thiele modulus. Fixed, moving and fluidized bed reactors. Reactors with three phases (gas, liquid and catalytic solid). Fluidsolid reactions.
E1.4.B. Chemical Unit Operations IV.B (30 lectures)
Filtration of ferment liquors. Extraction by twoaqueous phase systems. Reversemicelle extraction. Liquidliquid membrane technique. Supercritical fluid extraction. Membrane separation processes: ultrafiltration, reverse osmosis, pervaporation,. Flotation. Moving and fluidized bed adsorbers.
E1.4.P. Chemical Unit Operations IV.P (45 lectures)
Related pilot plant laboratory exercises: 45 units
Chemical reactors. Dynamic behaviour of reactors. Residence time distribution. Noncatalytic gassolid reaction. Evaluation of kinetic data. Heterogeneous catalytic reactions. Effect of transport processes on selectivity. Isothermal catalytic cylindrical reactor. Gasliquid and three phase catalytic reactors. Selection of reactors.
E1.5.B. Chemical Unit Operations V.B (30 lectures)
Instantaneous products: wetting rate, optimal agglomerate dimensions. Solidliquid extraction. Liquidliquid extraction. Insitu extraction of ferment liquors. Extraction with double aqueous phases. Supercritical extraction. Membrane separation processes. Crystallisation. Accumulation rate. Crystalliser devices. Adsorption. Freeze drying.
E1.5.P. Chemical Unit Operations V.P (30 lectures)
Related computer laboratory exercises: 15 units
Thermodynamic data requirement of engineering calculations. Literature search for thermodynamic data: bibliographies and data bases. Checking the quality of data. Methods of phase equilibrium calculations: g/v and equation of state methods. Main types of models for fluids: dense gas, lattice and cell models. Models used for practical engineering calculations. Estimation of model parameters from experimental data. Group contribution methods. Algorithmic and numeric problems of phase equilibrium calculations.
Multicomponent phase equilibrium calculations: bubble point, dew point, isothermal and adiabatic flashing, liquidliquid equilibrium calculations. Generalised theoretical stage model. Threephase stage model. The number of degrees of freedom of multistage separators (distillation, absorption, stripping and extraction columns). Shortcut methods and their application areas. Modelling of the rectification of nearly ideal mixtures, BP method. Acceleration of the convergence of the BP method. Modelling of absorbers and strippers by the Sum of Rates method. Simulation of liquidliquid extractors by the ISR method. NewtonRaphson type algorithms, their advantages and disadvantages. Modelling of threephase distillation, the BlockHegner method. Modelling of twoand threephase batch rectification. Model equations, basic algorithms (DiStefano, GalindezFredenslund methods). Introduction to the use of the PROCESS professional flowsheeting program package.
The first quarter of the exercises is computer laboratory exercise (column design and modelling). In the remaining part the students solve design problems individually (design of two column azeotropic, heteroazeotropic, extractive distillation and absorberdesorber systems).
E2. Process Control Theory and Techniques
E2.1. Process Control (45 lectures)
Related room exercises: 15 units
Related pilot plant laboratory exercises: 30 units
Review of the fundamentals of process control. Signal flow diagram, feed forward and feed back controls. Study of process control in the time, Laplace, and frequency domains. Time function, transfer function, frequency function and their relations.
Criteria of control, mathematical representation.
Basic controls, degrees of freedom, fundamental variables for composition control, pressure control, level control, temperature control, flow control. Theory and practice in the chemical industry. Miscellaneous measurements and controls.
Hardware of control. Analogue and digital devices.
E2.2. Computer Process Control I (30 lectures)
Related room exercises: 15 units
Theory of computer control. Basic sampling theorem, ztransform theorems. Stability analysis and design of sampleddata systems. Transfer functions, hardware elements. Developed control techniques and control systems.
Controllability and control structure design of multivariable systems. Tuning and stability in the case of multiple input multiple output (MIMO) systems. State space methodology.
Control of combined unit operations and technologies. Interactions in controlled unit operation and between the several controlled unit operations. Considering and elimination of the interactions, implicit and explicit decoupling, decoupling in a technology. Robustness, flexibility, resiliency.
Real time systems.
Instrumentation hardware.
E3. Process Modelling, Simulation and Synthesis
E3.1. Process Design and Modelling I. (45 lectures)
Related computer laboratory exercises: 30 units
Modelling of chemical processes and unit operations. Systems' decoding, variables, degrees of freedom.
Calculation of steady states in general. Modular and equation solving approaches.
Basic models and algorithms for phase equilibria calculation. Simultaneous, sequential, and adaptive modular techniques. Maximal closed subsystems and their identification. Identification of full information recycle systems by spanning tree algorithms. Optimal selection of tear variables. Signalflow graphs, linear submodels. Shortcut models. Algebraic solution of linearized systems by equivalent transformation of the signalflow graph and the same by Mason's rule. Decomposition of systems by mathematics and by engineering. Rigorous calculation of distillation columns by BP and SR methods. Numerical methods for solving systems of nonlinear equations. Philosophy and practical use of professional simulation softwares (PROCESS, ASPENPLUS).
Transient processes in the chemical engineering practice. Transient models and their solution. Numerical problems in transient simulation. Boundary value problems in the chemical engineering practice. Types of description. Solution by finite differences and weighted residual methods. The methods of finite elements and boundary elements. Theory and application of artificial neuron networks.
E3.2. Process Design and Modelling II. (30 lectures)
Related computer laboratory exercises: 45 units
Theory and praxis of process design. Process synthesis approaches. Hierarchy levels. Continuous and batch processes. Levels and methods for cost and profitability estimation. Special mathematical tools for process design and systems engineering: optimization over noncontinuos variables, implicit enumeration, branch & bound, discrete dynamic programming. Destination of feeds, products, byproducts, purge, and losses in the recycle structure with relation to the conversion and selectivity in the reactor and the whole process. Optimal reactor design in the context of the full process; reactorseparator systems. General structure of separator subsystems. Synthesis of rectification trains. Heuristics, load factors, dynamic programming for sharp separation. The synthesis problem of sloppy separation. Rectification energetics, reversible distillation model, stepwise heat turnover, variants of heatpump assisted distillation, energy integration. Distillation in the heat cascade. Residue curves, pinch curves, separatrices, region boundaries, solvent selection for batch and continuous azeotropic and/or extractive distillation. Other separation processes. Conventional design of energy supply and recovery systems, pinch technology, and MINLP methods. Waste and environmental problems. Pinch technology for waste water minimization and treatment.
E3.3. Process Design and Modelling Case Study
Related library exercises: 30 units
Related computer laboratory exercises: 150 units
Full scale process synthesis and technological design of a particular industrial process. The practice commences with data collection and literature search. Process synthesis based on hierarchical approach. Modelling by professional simulation softwares (CHEMCAD, ASPENPLUS, HYSYS. Technological design of unit operations, allocation and design of control loops, safety problems, profitability analysis, optimization, documentation.
E4. Optimisation (30 lectures)
Related computer laboratory exercises: 15 units
Definition of the objective parameter and objective function. The relation of the mathematical model to the objective function. Boundary conditions. Several case studies of chemical processes. Methods for the optimisation of continuous processes: Lagrangemultiplicator method. Linear programming. Nonlinear programming. Methods working with derivatives and without derivatives. Random selection. Case studies.
Optimisation of batch and non steadystate processes. Pontryagin theory.
Optimisation of several objectives. Trade off methods. Examples.
Practices: optimisation of chemical processes with the help of own computer code.
E5. Design and Analysis of Experiments (30 lectures)
Related room exercises: 15 units
Error propagation law. Precision of measuring instruments. Error analysis of a complex measurement. Fitting nonlinear functions. Strategy of experimental design: screening design and more detailed mapping of the response surface, optimisation. Analysis of variance. Random blocks, cross classification and hierarchical classification for several factors. Latin squares. EVOP method for optimising an industrial technology when it is in operation. Taguchi method for improving quality of products, for reducing the variation of quality. Exercises and openended practice using the Statgraphics professional software tool.
Elective courses (all the sections, including postgraduate and foreign language):
E6. Chemical Process Dynamics (30 lectures)
The application of dynamic modelling for chemical processes. The creation of the dynamic models. Similarities and deviations compared with steadystate models and modelling.
Work with differential equation systems, derivation and solution. Solution methods, algorithms and numerical methods. Programming.
Software for the solution of dynamic models of chemical unit operations and processes. Exercises.
Dynamic modelling of different unit operations, combined unit operations, and chemical processes.
Evaluation and interpretation of the results considering operability and controllability aspects.
E2.3. Computer Process Control II (30 lectures)
Related room exercises: 15 units
Fundamentals of process control. Control of multiple input multiple output (MIMO) systems, theory and practice.
Analysis of sampling control loops. Synthesis of sampling control loops.
Dynamic modelling of different unit operations, combined unit operations, and chemical processes. Evaluation and interpretation of the results considering operability and controllability aspects. The special problems of the control of several chemical unit operations, processes, and technologies. Possible solutions of these special problems.
Control of different chemical unit operations such as reactors, distillation and absorption columns, extractors, evaporators, pH control. Adaptive control, dynamic simulation.
Implementation of digital control. Instrumentation hardware.
E7. Chemical Process Energetics (30 lectures)
Basic concepts, technical thermodynamics.
Comparison of heat engine, heat pump and refrigerating machine. Concept and terms of exergy. Definitions of efficiency. Exergy analysis. The CarnotClausius cycle and the steam power stations. Power station variants and their relation to the chemical plants.
Cycles of mechanical, absorption, and chemical heat pumps. Calculation and technological design of mechanical heat pump and refrigerating machine cycles. Types of heat pump assisted distillation, their comparison and economical analysis. Energetics of evaporation and distillation, reversible model and energy saving alternatives. Energy integration.
Pinch technology, composite curves, grand composite curves, heat cascade. Synthesis of heat recovery systems, pinch rules. Relation between thermal processes and the heat cascade. Overall site pinch analysis and optimization.
E8. Pinch Technology (30 lectures)
Related computer laboratory exercises: 15 units
The problem of energy recovery systems. Conventional design procedure. Construction of composite curves and pinch point. Approach temperature and minimum heat turnover. Grand composite curve and heat cascade. Pinch rules and rules for stream branching at pinch. Grid representation, evolution and loop breaking. Supertargeting for grassroot design and retrofitting. Pinch and pressure drop. Divers pinch.
Steam generation, heat pump, turbine, thermal process and stack gas systems in the heat cascade and along the grand composite curve. Selection among fuels, steam and gas turbines, steam line pressure levels. Utility grand composite curve. Sensitivity tables, constrained problems, total site integration.
Fresh water and waste water minimization by component transport pinch technique. Fresh water composite, pinch, and pinch rules. Distributed waste water treatment optimization by pinch technology.
Pinch technology for batch processes.
E9. Environmental Protection in the Chemical Industry (30 lectures)
Actual problems of the environmental protection. International regulations and standards. The pollution problems and environmental protection in the world and in Hungary.
Classification and the sources of the waste. Process waste and utility waste. Internal and extrinsic waste. Waste reduction methods. Waste minimisation at the unit operations.
Waste elimination incentives during grassroot process design and retrofitting design.
Two level strategy for waste elimination. Closed cycle processing.
E10. LiquidLiquid and SolidLiquid Extraction (30 lectures)
Applications of L/L extraction. Empirical correlations for distribution ratio. Selectivity of mixture solvents. Distribution of amphotlytes in pH field. Effect of pressure and temperature on mutual solubility.
Fractionating processes: Calculation of Craig, Martin and Synge distributions. Laboratory and plant devices. Calc. of O'Keeffe distribution. Steady state and transient concentration profiles. Examples for fractionating: chiral isomers, oligo and polypeptides, nucleid acids, viruses.
Design and scaleup of mixersettlers, based on laboratory experiments. Separation of emulsions. Flooding velocity in packed and sieve tray columns. Scaleup of agitated extractor columns based on pilot plant experiments. Effect of axial dispersion. Material transfer in agitated columns. Effect of impurities.
Liquid membrane techniques and material transport theory. Carrier materials. Technological implementation. Reactive extraction. Extraction with reflux. Analogy with distillation.
Inorganic applications: metal ions, wastes, waste water purification. Organic applications: pharmaceutical materials, penicillin, double solvent extraction for biological materials.
Solidliquid extraction. Selection of devices. Preparatory processes. Solvent recovery. Design and scaleup of industrial countercurrent devices based on laboratory measurements.
Supercritical extraction: solubility, effective parameters, devices. Application in pharmaceuticals, seasons, polymers, hydrocarbons, environmentals.
E11. Modelling of Countercurrent Processes
Multicomponent phase equilibrium calculations: bubble point, dew point, isothermal and adiabatic flashing, liquidliquid equilibrium calculations. Generalised theoretical stage model. Threephase stage model. The number of degrees of freedom of multistage separators (distillation, absorption, stripping and extraction columns). Shortcut methods and their application areas. Modelling of the rectification of nearly ideal mixtures, BP method. Acceleration of the convergence of the BP method. Modelling of absorbers and strippers by the Sum of Rates method. Simulation of liquidliquid extractors by the ISR method. NewtonRaphson type algorithms, their advantages and disadvantages. Modelling of threephase distillation, the BlockHegner method. Modelling of twoand threephase batch rectification. Model equations, basic algorithms (DiStefano, GalindezFredenslund methods). Introduction to the use of the PROCESS professional flowsheeting program package.
The first quarter of the exercises is computer laboratory exercise (column design and modelling). In the remaining part the students solve design problems individually (design of two column azeotropic, heteroazeotropic, extractive distillation and absorberdesorber systems).
E12.
E13.
Lecturing subjects of the Mechanical Engineering Group
1. Machine elements (2+0+0)
Machine elements, applied in the chemical industry, special construction materials
2. Machine drawing (0+3+0)
Sketch makeing, technical design reading, stereoscopic vision
3. Mechanical operations (2+1+0)
Mechanical operations of raw materials and products of chemical industry, ie: storage and transport of fluids, gases and bulk materials, characterisation, grinding, feeding classification and agglomeration of particulate solids
4. Practice in mechanical laboratory (0+0+6)
Measurement of characteristics of the bulk materials and of the machines learnt in mechanical operations
5. Computer aided design (0+2+0) (optional)
Machine drawing by computer
6. Manufactoring (0+0+2) (optional)
Using of different machine tools, welding in the workshop
7. Protection from dust, air cleaning (2+0+0) (optional)
Dust filters, dust separation
8. Fluid mechanics in chemical industry (2+0+0)..(optional)
Non newtonian fluids, multi phase flow
RESEARCH FIELDS
R1. DISTILLATION AND ABSORPTION
R1.1. Determination of VapourLiquid Equilibria and design of
Packed Columns.
Determination of VapourLiquid Equilibrium.
The design of rectification columns based on accurate VapourLiquid Equilibrium (VLE) measurements. In the literature a number of VLE data are available, however design of rectification columns often required to determine VLE of the unknown system, and to evaluate the measured data by computer. There are special difficulties to measure the VLE of non random and great relatively volatile systems.
Design packed rectification columns.
In the industrial practice the use rectification columns with structured packing has an outstanding importance. This columns have good separation effect, great capacity and low hydrodynamic pressure drop. There is a task to determine the height and diameter of the columns with new packing.
R1.2. Development on distillation and absorption technologies
Confirmed thermodynamic data are necessary for developing distillation and absorption technologies. Vapour tension of pure materials and vapourliquid equilibrium data of binary and multicomponent mixtures are experimentally determined and the thermodynamic consistency of the measured data are checked in this research work. Selection of feasible entrainers for azeotropic and extractive distillation, laboratory experiments on such systems and their computer modelling are standard parts of the developing activity. Study on the hydrodynamics and material transfer properties of random and structured packing, as well as technological sizing and determination of the main operational parameters are also included. The research group has and exceptional long history and firm knowhow as the consequence of their many industrial contracts.
R1.3. Modelling and calculation of thermodynamic properties
R1.3.1. Consistency testing of thermodynamic data
Efforts are made to extend the residual method by Van Ness (proposed for binary VLE data at moderate pressures) to ternary mixtures, and to binary highpressure VLE and LLE data. The ternary program is ready for moderate pressures.
A novel method of testing consistency of thermodynamic data banks based on the testing of deviations from exact differential equations. At present it is developed for pure component data with one or two differential equations as constraint, examples are mutual consistency of vapor pressure and heat of vaporization data and that of volumetric (PVT) and caloric (CP and JouleThomson coefficient) data, respectively, and also for binary VLE data.
R1.3.2. Modelling phase equilibria
Statistical thermodynamic models are being built resulting in EOS capable to describe and predict highpressure equilibria of systems containing both apolar and polar components. A group contribution EOS model containing nonspecific and specific attraction terms has been developed and tested for nalkanes, aliphatic ethers, 1alkanols and their mixtures.
Methods of parameter estimation, assessing phase stability etc. relevant to EOS models are also studied.
A special field is the modelling of solidfluid phase equilibria for supercritical extraction.
A monograph of 240 pp. has been published in Hungarian with the title "Equations of state for calculation of phase equilibria", covering statistical thermodynamics background of models and their systematization, its English version is under processing.
Res 1.3.3. Calculation of properties of complex hydrocarbon mixtures
Methods of characterization and engineering calculations are investigated including continuous thermodynamics. An extensive review paper has been published in Hungarian.
Res 1.3.4. VLE data bank
Literature data on multicomponent VLE are collected, assessed and put in a data base. Binary VLE data have been bought from Warsaw and supplied with computer programs for checking consistency and parameter estimation.
R4. Modelling of batch and continuous countercurrent separation processes
Computation methods and algorithms for the modelling of countercurrent separation processes (rectification, absorption, extraction in plate columns). Three phase continuous and batch distillation with and without chemical reaction.
Batch extractive distillation (in collaboration with the INSA de Lyon). Pilot plant experiments. Studying of different operational policies, determination of the optimal operational parameters.
R2. EXTRACTION AND LEACHING
R2.1. Kinetics of Soxhlettype and Supercritical SolidLiquid Extraction of Natural Products. Mathematical modelling and optimization of the process.
Soxhlettype and supercritical extraction are similar operations in some points. Both are semibatch processes using fresh solvent continuously recycled from a separator where extracted material is accumulated. The aim of the work is to calculate the relative amount of unextracted material as a function of time, solvent consumption and solvent holdup in the extractor vessel as well as in the pores or cells of the solid natural product.
The mathematical model is an analytical solution of Fick's differential equation with boundary conditions corresponding to the operation. It describes concentration in the extract and in the pores as a function of time and all other variables mentioned above. All parameters affecting the resistance of the natural product against diffusion are concentrated in a single constant that has a dimension of time. Its value can be determined experimentally. Then the model gives the batch time for a certain percentage of extraction as a function of the operational parameters.
Experimental data have been taken to show the fit between the model and measured results. These include both Soxhlet and supercritical (SC) extraction. In the latter case a method has been developed for the determination of the solvent holdup of the solid that is otherwise directly hardly measurable. In some cases further simplification of the model is possible.
Further aim of the research is optimization of the procedure because the derived functions are suitable for the prediction of the effects of the operational parameters and they can serve as input signals to more complex systems.
The work has been done in cooperation with the University of Maribor, Slovenia.
R2.2. Supercritical fluid extraction equipment and R&D capabilities
Equipment:We have a batch extractor unit of 1l and 5l extractor vessel volume and a column for continuous countercurrent separation at supercritical or near critical conditions. The height of the column is 3.6 m, diameter is 0.046 m. Maximum working pressure is 320 bar and working temperature is 0120 °C.
Research fields:
Extraction of odoriferous substances (e.g. rosemary, lavender) [1]
Total extraction of medicinal plants (e.g. camomile, thyme) [4]
Aroma recovery from spices (e.g. dill, fennel)
Fractionation of products (e.g essential oils and fatty oils from caraway seeds) [2]
Oil recovery from oilseeds (e.g. corn germ, sunflower) [3]
Extraction of animal fats (e.g. fish)
Removal of residual solvents from pharmaceuticals (solvents: methanol, hexane, cyclohexane, dichloromethane)
Separation of enantiomers using chiral resolution agents (e.g. cis and trans isomers of chrysanthemic and permetric acids) [5], [7]
Separation of organic/water systems (e.g. alcoholwater) [6]
R3. REACTIONS
Mathematical modelling of residence time distribution and chemical reactions
The knowledge of the residence time distribution (RTD) in an isothermal tubular reactor with nonNewtonian laminar flow is very important for the prediction of conversion for homogeneous reactions [1,2].
The performance of an isothermally operated continuous flow reactor cannot be predicted simply by using the expression of the RTD density function. The paper [3] treated the effect of micromixing on the conversion of the autocatalytic reaction in a continuous stirredtank reactor.
The SoaveRedlichKwong equation of state was used to describe the nonideality of reacting mixture in modelling of a methanol synthesis reactor [4].
R4. MIXING OF LIQUIDS
R4.1. Power Consumption. Measurements were made with paddle, centrifugal, propeller mixers and six blade turbine impeller, threeblade marine and plate type propeller agitators with liquids of various viscosity in the laminar, transitional and turbulent range of low. The measured data were presented as EulerReynolds diagrams. It has been shown that the effect of Froude number on the power consumption of mixers is negligible (1,2,3).
The power requirement of anchor, helical ribbon impellers and screw agitators for the case of agitating Newtonian and pseudoplastic liquids was measured. These types of impellers are being used in industry for the agitation of high viscosity liquids. Equations were given to calculate the power requirement of these agitators for Newtonian and pseudoplastic liquids of high viscosity. The screw agitator was investigated in centred and eccentric positions as well as in a draught tube (4,5,6).
R4.2. Homogenisation Efficiency. The homogenisation time of anchor, helical ribbon and screw, gate and multipaddle agitators in the laminar region and that of marine type and plate type propeller agitators in turbulent region were measured to classify the agitators according to homogenisation efficiency (7,8).
R4.3. Heat Transfer in Agitated Vessels. Heat transfer coefficient to helical coils and vertical tube baffles in agitated vessel were measured in Newtonian liquids with turbine impeller and marine type and plate type propeller agitators in turbulent region. Regression relation, containing a modified Reynolds number were obtained which are suitable both cooling and heating applications (9,10,11).
R5. PROCESS DESIGN AND INTEGRATION
R5.1. Feasibility of distillation for nonideal systems
Although the theory of distillation boundaries and regions is fairly developed in the past decade in the chemical engineering literature, there are some questions remained waiting for answer. First of all, the strictness of simple distillation boundaries proved to be week for continuous distillation in some particular cases. When and how these boundaries can be crossed by a simple feed rectification column is an open question yet. Second, it is also an open question how these boundaries behave with multiple feed columns, especialy in the case of extractive distillation. How these details effect the selection of solvents for extractive and azeotropic distillation is not yet even touched in the literature. Third, the separatices, boundaries and regions are usually studied in three component mixtures, i.e. in two dimensions. However, they can take more complicated formations in multicomponent mixtures, i.e. in higher dimensions. Even the mathematical description of higher dimension manifolds is not yet perfectly finished, and surprises may be expected from studying these possibilities.
R5.2. Hibrid separation systems
Separation boundaries are related to just one method of separation, usually distillation. Crossing these lines can be achieved by application of additional separation phenomena. The best known of these possibilities is applying liquidliquid phase separation together with a mainly vapourliquid equilibria based distillation process (azeotropic distillation). However, any other separation process can be combined with the basic process. Azeotropic, extractive, reactive distillation, salt distillation, combination with membrane processes, with absorption, with cristallysation, etc. may all be sorted under the heading of hybrid separation systems. How these combinations can be reasonable developed or selected, optimally designed with energy integration, compared with each other is the main topic of these researches.
R5.3. Reactive distillation
Reactive separation is usually applied for enchancing the equilibrium governed reaction by removing one or more of the reaction products. On the other hand, reactive separation is a complicated separation process reproducing complicated phenomena. One of these is the phenomenon of reactive azeotropy. This is a stationer point in reactive distillation of mixtures of components not forming azeotropic mixtures (or forming azeotropic mixtures at different compositions). This phenomenon may happen even in ideal mixtures. Once the phenomenon of azeotropy emerges, some kind of separatices and separation boundaries may also emerge. The situation is even more complicated when the reaction kinetics is also taken into account. In contradiction to the isolated singularities occuring in equlibrium systems, nonisolated singularities may, and usuallly do, happen to occur in the kinetic systems. Similar phenomena may occur in other reactive separation systems, too. The systematic study of the equilibrium and kinetic reactive separation systrems is just started.
R5.4. Design Strategy for Selecting Energy Efficient Distillation Processes
A design strategy for selecting energy efficient distillation processes considering different types of heat pump structures (vapour recompression, bottom flash, closed cycle, absorption cycles) and energy integration is proposed based on the pinch analysis, primary energy rate, energy cost factor, and estimated payback time of excess capital. On the basis of the , energy costs and efficiencies simple expressions are proposed for preliminary economic analysis and design of heat pump assisted and integrated distillation processes. The influence of heat pump type and the exchanger minimum approach temperature on the economic figures is presented and the water management aspect of the technologies are indicated. The simulated results of the different energy efficient processes are compared to conventional schemes.
The strategy is demonstrated and verified by industrial case studies. From economic standpoint the different absorption heat pumping schemes proved to be the processes of choice for C4 separations but from the water management aspects the mechanical heat pumping schemes became more favorable. All heat pumping systems show better economic figures than the conventional design, using only steam and cooling water.
R5.5. Energy integrated distillation system design enhanced by heat pumping and dividing wall columns
The influence of relevant parameters on the economics of distillation plants involving absorption and motor type heat pumping as well as dividing wall columns (Petlyuk columns) is scrutinised and the results are compared to the conventional solutions.
The result show that from an economic viewpoint the heat integration is the best solution. In case of stand alone columns heat pump is competitive and the dividing wall columns can be considered only in the case of the separation of multicomponent mixtures if heat integration is not realisable.
Operability studies are also carried on for the systems investigated. The study shows that every kind of energy integrated solution can be controlled by decentralised control systems.
R5.6. Energy recovery systems
Synthesis of process subsystems for supplying and recovering energy is a basic task in process design. The narrowest problem is synthesis of heat exchanger networks with minimum annual cost. Subtargets such as minimum number of units, minimum complexity, maximum energy recovery, minimum heat transfer area, etc. may be considered as targets of simplified problems. The research for efficient design algorithms accelerated after discovery of the pinch phenomena. However, some important subproblems remained to solve, e.g. efficient design far from pinch, or design with significantly different heat transfer coefficients. "Pinch technology" is a wide variety of methods based on the pinch principle, including assignement of thermal separation units, secondary steam generation, power generators and heat pumps along the heat cascade, total site integration, etc.
Our research was first focused on the heat exchange network synthesis methods. Later we started researches on the general energy integration of processes and its relation to pinch, e.g. UGCC curves, but this research is classified under an other heading.
R5.7. A global approach to the synthesis and preliminary design of
integrated total flowsheets
A combined approach is under development for synthesising realistic processes efficiently, which utilises the advantages of the different methods for process design:
Hierarchical methods are used to create good preliminary flowsheets and screen these process alternatives with simple energy integration using shortcut models and simple estimation of the costs.
The userdriven synthesis technique is called upon to tackle all the constraints, complex energy integrations and additional implicit knowledge derived during the conceptual design that were unknown at the outset. The controllability of the particular process scheme is measured by using steady state multivariable synthesis tools.
A bounding strategy based on performance targets is developed to reduce the search space which is usually enormously large.
Algorithmic methods are suggested for the optional final tuning, the optimisation of superstructure postulated in the previous steps and the remaining heat exchanger network synthesis problem. For the final designs the use of rigorous models and optimisation techniques is provided in order to account more rigorously for features such as interconnections and capital costs.
The effectiveness of this combined approach is demonstrated by representative industrial case studies.
R5.8. Process Integration in Refineries for Energy and Environmental Management
A computer aided design strategy for generating and evaluating integrated process flowsheets have been developed for refineries. Beside economical and energy considerations the environmental managements aspects (waste minimisation and water management) are also included. For the development of the strategy both the traditional heat cascade principle (pinch analysis) and the algorithmic approach (MINLP) are applied.
A special attention is paid to the heat recovery problems using mechanical and absorption heat pumping schemes at light hydrocarbon separation systems. The strategy is tested by industrial design and retrofitting problems e.g. lubricating oil production, C4 and C3 separations, crude as well as gasoline distillation.
R6. CONTROL AND OPERABILITY
R6.1. Assessing plant operability during process design
A systematic procedure is under development for assessing plant operability during overall process design. At the preliminary stage of the process design the number of manipulated variables is scrutinised and a degrees of freedom analysis is performed in order to satisfy the process constraints and to optimise all the operating variables. The modification of flowsheets, the overdesign of certain pieces of equipment and the neglect of the least important operating variables are to be considered as restorative measures for controllability. At the more rigorous design level the controllability of the particular process scheme is measured by using first steady state and later dynamic multivariable synthesis tools (RGA, SVDA, NI, MRI, ...etc.) before performing dynamic simulations of the process together with its control system. In addition to the controllability concerned with the dynamic characteristics of the process in the neighbourhood of the steady state the switchability concerned with the dynamics of changes of operation from one steady state to another should be considered during the process design in order to assess the ability of the process to cope with large operating changes and to judge the trade off between plant integration and operability.
R6.2. Transformation of Distillation Control Structures
Interaction problems can occur if both of the product concentrations are controlled in a twoproduct distillation column. Interaction can be reduced by selecting a proper control structure (control structure: a certain pairing of the manipulative and controlled variables). Selecting from the possible control structures requires the models of the structures. The transformation procedure can compute the feasible control structure models if a base control structure model is already given.
The subject of the project is to check the HäggblomWaller method for both steadystate and dynamic case of modeltransformation. Since the full scale model of a distillation column is too complex for the transformation method to handle, it is necessary to find the allowable extent of model simplification in the base control structure model. The model must be enough simple to use it in the transformation method and also enough complex to get satisfactory models of the nonbase control structures resulted in the transformation.
R7. ENVIRONMENTALS
Waste reduction in the Chemical Industry
If cleaner technologies are to be designed for sustainable environment there are several strategies for the process and utility waste reduction. In case of the utility waste the solution seems to be easier compared to the problem of the process waste: both the pinch technology for the minimisation of the energy consumption and the conceptually based approach for waste water minimisation are able to handle and solve the problem of individual plants or the entire factory. In case of the process waste the situation and the alternatives for the waste reduction are more complicated. The systematic techniques developed and used for process improvements reach their limits at plant level. For further development, however, the decisions made on the plant level should be coordinated on the factory level considering the possible interactions among the different plants. With the use of the proposed systematic procedure for process waste minimisation of a factory closed cycle processing and the cost effective minimal global emission can be realised.
Clean technologies
Membrane separations
The theory and applications of membrane technologies are investigated. The major membrane operation investigaed is the pervaporation, however, other separations are also studied (e.g. nanofiltration, reverse osmosis).
The model of pervaporatnio is developed and applied for the modelling of clean technologies such as hybrid operations, coupling of distillation and membrane units, etc.
Cleaning of waste water with physicochemical tools
The waste waters are not always allowed to process by biological tools and also from economic point of view the physicochemical tools can be favoured. These methods are e.g. stripping, desorbtion, membran operations.
Industrial case studies show the effectivity of such tools.
Solvent recovery
The solvent recovery is a powerfool tool of the sustainable development. Indutrial case studies show the importance of such topics.
The solvent recovery means in several cases the separation of quaternary highly nonideal mixtures. New hybrid separation proecesses are designd. The core such processes is a new separation: the extractive heterogeneousazeotropic distillation, which enables to significantly simplify the separation of highly nonideal mixtures.
Synthesis of mass exhange networks (MEN) with mixed integer nonlinear programming (MINLP)
A new rigorous MINLP model for MEN synthesis of dehydration system consisting of a distillation column and a pervaporatin is under development. Resulting from the need for rigorous modelling, several mathematical tools for the GAMS environment are to be adopted.
The optimal design of the system investigated is determined, the parameters are: number of trays, feed tray location, reflux ratio, separation factor, membrane units and their position. Optimal structure with and without recycle are presented.
Economic and controllability study of energy injtegrated separation schemes
the work is based on studying and rigorous modelling, design, simulation, optimization, environmental impact analysis, and control aspacets investigation of various energy integrated schemes. In one of the last works five different energyintegrated distillation schemes: two direct sequences with forward or backward heat integration (DQF, DQB), the Petlyuk or dividing wall system (SP), and two sloppy separation sequences with forward or backward heat integration (SQF, SQB) are investigated for the separation of a ternary mixture from economic and controllability points of view and compared to the nonintegrated conventional direct separation scheme.
The economic study shows that the optimal DQB has the highest total annual cost (TAC) saving: 37 %. SQF and SQB have 34 % and 33 % TAC savings, respectively. The controllability analysis, based on steady state indices, shows that the control loops of DQF and DQB have less interactions than in the case of the other energyintegrated schemes studied. The dynamic investigations also prove that DQF and DQB show similar controllability features than the nonintegrated conventional scheme. Although the SQF and SQB have good economic features but their controllability features, especially the ones of SQB, are significantly worse than those of DQF and DQB. Therefore the controllability features should play a significant role at the selection of the energyintegrated distillation schemes.
Process synthesis of chemical plants
A combined methodology for process synthesis of integrated chemical plants is presented. The energy consumption, investment, environmental and operability challanges ae considered for saving the complex task of synthesizing processes of practical importance. Shortcut design tools, userdriven algorithm, rigorous process design methodologies and combination of conventional pinch technology with energy analysis are included. Interactions between the reactor and other subsystems, energy integration, heat pumping, complex column arrangements, and rational integration of heat and mass exchange systems are also taken into account.
Research topics of the Mechanical Engineering Group
1. Solidgas twophase flow. Different forms of pneumatic conveying: in horizontal and vertical pipe, aerokinetic and fluidized canal
2. Investigation of particle motions in fludized bed by discret particle simulation (DPS) method
3. Investigation and modelling by computer the work of airair injectors
INTERNATIONAL COOPERATIONS