A modified, non-equilibrium model of micromixing has been applied to describe mixing and chemical reaction in a stirred tank reactor. Modification of the model is based on taking into consideration effects of turbulen...
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A modified, non-equilibrium model of micromixing has been applied to describe mixing and chemical reaction in a stirred tank reactor. Modification of the model is based on taking into consideration effects of turbulent shear on dissipation of the passive scalar. Predictions of the model have been compared with the experimental data and results of simulations neglecting shear effect.
A model-based optimization of an industrial fed-batch sugar crystallisation process is considered in this paper. The objective is to define the optimal profiles of the manipulated process inputs, the feeding rate of l...
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The aim of this paper is to give an overview about some ideas that have been introduced in past few years to the course Automatic Control Fundamentals at FCFT STU. These involve heavy use of information technologies a...
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The aim of this paper is to give an overview about some ideas that have been introduced in past few years to the course Automatic Control Fundamentals at FCFT STU. These involve heavy use of information technologies and reduction of repetitive pedagogic work using e-learning techniques for the course with a large number of students. The paper discusses reasons for this change as well as concrete technologies in question.
To simulate adequately the process of heat exchange taking place in a solar collector, structural scheme of heat transfer in the collector wall has been developed. Structural model of heat exchange, which is visualiza...
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To simulate adequately the process of heat exchange taking place in a solar collector, structural scheme of heat transfer in the collector wall has been developed. Structural model of heat exchange, which is visualization of the interaction and transformation of heat flows both on the boundary and inside a plate, has been built based on the solution of the task of thermal conductivity of the plate with boundary conditions of the third type and due account of internal sources of heat induced by IR irradiation. The model makes it possible to identify thermal-physical parameters.
A model-based optimization of an industrial fed-batch sugar crystallisation process is considered in this paper. The objective is to define the optimal profiles of the manipulated process inputs, the feeding rate of l...
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A model-based optimization of an industrial fed-batch sugar crystallisation process is considered in this paper. The objective is to define the optimal profiles of the manipulated process inputs, the feeding rate of liquor/syrup and the steam supply rate, such that the crystal content and the crystal size distribution (CSD) measures at the end of the batch cycle reach the reference values. A knowledge-based hybrid model is implemented, which combines a partial first principles model reflecting the mass, energy and population balances with an artificial neural network (ANN) to estimate the kinetics parameters - particle growth rate, nucleation rate and the agglomeration kernel. The simulation results demonstrate that the very tight and conflicting end-point objectives are simultaneously feasible in the presence of hard process constrains.
The problem of using bioethanol as a fuel additive in Poland and in other countries is presented. Dehydration methods, such as pressure swing adsorption (PSA), pervaporation (membrane technique) as well as hybrid meth...
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The problem of using bioethanol as a fuel additive in Poland and in other countries is presented. Dehydration methods, such as pressure swing adsorption (PSA), pervaporation (membrane technique) as well as hybrid method are described.
Catalyst fragmentation and polymer growth in the early stages of propylene polymerization has been investigated using different Ziegler-Natta catalysts. Polymerization was carried out in slurry under mild conditions a...
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Catalyst fragmentation and polymer growth in the early stages of propylene polymerization has been investigated using different Ziegler-Natta catalysts. Polymerization was carried out in slurry under mild conditions and stopped at low yield. Scanning electron microscopy (SEM) has been used to characterize the surface and cross sectional morphology of polymer particles at different stages of particle growth. Different fragmentation behavior is observed, and it is found that the way that catalyst fragments in the early stages of polymerization is greatly influenced by the porosity of the catalyst. When a less porous catalyst was used, the resulting mass diffusion limitation causes layer-by-layer fragmentation, starting at the outer surface of the catalyst particle to the center. In contrast, for highly porous catalyst, monomer can easily penetrate into the pores of the catalyst / polymer particle. The polymer growing throughout the particle results in a coarse and instantaneous fragmentation.
Very light boehmite from supersaturated sodium aluminate (SA) solutions was reported by a hydro-thermal precipitation process with boehmite seed, which came from the hydrothermal homogeneous precipitation between alum...
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Very light boehmite from supersaturated sodium aluminate (SA) solutions was reported by a hydro-thermal precipitation process with boehmite seed, which came from the hydrothermal homogeneous precipitation between aluminum sulfate and urea. Precipitation conditions of single-phase boehmite with very light tape density and their effects on crystal structures and morphologies were studied by ICP-AES, XRD and SEM. It was determined that very light single-phase boehmite can be obtained by precipitation 48h at 100°C or precipitation 3 h at 187°C, but precipitation conditions had not marked effects on foregoing properties of the products. The very light boehmite seed precipitation process not only enrichs the traditional gibbsite seed precipitation process, but also provides a preparation method of very light boehmite.
Two competitive-parallel chemical reactions proceeding between HCl, NaOH and CH2ClCOOC2H5 in water- polyethylenepolypropylene glycol systems are applied to study micromixing of liquids of different viscosities in a re...
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Two competitive-parallel chemical reactions proceeding between HCl, NaOH and CH2ClCOOC2H5 in water- polyethylenepolypropylene glycol systems are applied to study micromixing of liquids of different viscosities in a reactor with the Couette flow. A new micromixing model is proposed to interpret experimental results. Additionally a full set of physicochemical data characterizing the test reaction system is presented.
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