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Modelowanie procesu rozdrabniania mieszaniny materiałów o różnej twardości

Otwinowski H., Zhukov V. P., Osipov D. A.

Materiały Ceramiczne

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2017

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T. 69, nr 4

292--296

PL

Rozdrabnianie mieszaniny materiałów o różnej twardości charakteryzuje się tym, że ziarna produktu mielenia bardziej twardego składnika mają większe rozmiary w porównaniu do ziaren produktu mielenia składnika o mniejszej twardości. Klasyfikacja ziaren takiej mieszaniny produktów umożliwia zwiększenie udziału żądanego składnika w gotowym produkcie. Analiza teoretyczna procesu rozdrabniania mieszaniny materiałów została przeprowadzona w ramach koncepcji modelowania procesów chemicznych na podstawie dyskretnych postaci równania Boltzmanna. W badaniach eksperymentalnych opracowano odpowiednią metodykę przeprowadzenia testów i obróbki danych doświadczalnych, otrzymanych przy użyciu laboratoryjnego młyna fluidalnego. Na podstawie analizy teoretycznej przedstawiono model do opisu kinetyki rozdrabniania każdego składnika mieszaniny, co umożliwia ocenę efektywności zwiększenia udziału żądanego składnika w gotowym produkcie. Opracowano metodę rozwiązania równania procesu rozdrabniania selektywnego oraz algorytm umożliwiający zastosowanie komputera do obliczeń. Po przeprowadzeniu badań eksperymentalnych otrzymano wyniki rozdrabniania binarnej mieszaniny o różnej zawartości poszczególnych składników w nadawie młyna fluidalnego. Identyfikację eksperymentalną modelu przeprowadzono, wykorzystując wyniki oddzielnego rozdrabniania składników mieszaniny. Parametrami identyfikacji były współczynniki zależne od właściwości wytrzymałościowych każdego składnika. Adekwatność modelu sprawdzono na podstawie wyników rozdrabniania mieszaniny o różnych udziałach masowych badanych materiałów. Do sprawdzenia adekwatności modelu wykorzystano dane doświadczalne inne niż te, na podstawie których przeprowadzono identyfikację parametryczną modelu. Porównanie wyników obliczeń i eksperymentów wykazało adekwatność przedstawionego modelu matematycznego oraz możliwość przeprowadzenia oceny efektywności rozdziału składników mieszaniny. Przeprowadzone badania umożliwiły rozszerzenie koncepcji modelowania procesów chemicznych na podstawie dyskretnych postaci równania Boltzmanna o model procesu rozdrabniania selektywnego mieszaniny materiałów o różnej twardości.

EN

At joint comminution of components with different grindability, the particles of more strong material are of larger size than the particles of less strong material. The size classification of such a mixture allows enriching the objective component in the end product. The computational research of the comminution process of a materials mixture was done using the conception of chemical processes modelling based on the discrete analogues of the Boltzmann equation. A special program for experimentations and experimental data treatment obtained at a lab-scale fluidized bed jet mill was developed. Based on a theoretical analysis, a model to describe the comminution kinetics for each component of a mixture was developed. It allows estimating the efficiency of enrichment of the end product by the objective component. A method to solve the equations of the selective model of comminution and the computer algorithm for its realization was developed as well. The experimental data on comminution of binary mixture of components at their different content in the fluidized bed jet mill hold-up were obtained. These data were used to identify the model with respect to the parameters that characterized the grindability of each component. The model adequacy was checked using the data on joint comminution of mixtures with different content of components. These data were not used for the model identification. Comparison of calculated and experimental data showed the model adequacy and possibility of its usage to estimate the efficiency of components separation. The investigation allowed generalizing the conceptions of chemical processes modelling based on the discrete analogues of the Boltzmann equation to the case of selective comminution of a mixture of components with different grindability.

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Time requirements in closed and open batch distillation arrangements for separation of a binary mixture

Zhao Shuo, Bai Peng, Guo Xianghai, Tang Ke, Li Guangzhong

Polish Journal of Chemical Technology

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2014

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Vol. 16, nr 4

66--74

EN

Batch time requirements are provided for the separation of binary zeotropic mixtures in two different multivessel columns (with and without vapor bypass), a non-cyclic two-vessel column and a regular batch column based on dynamic simulations. The first three columns are operated as closed (total reflux) systems and the regular batch column is operated as an open (partial reflux) system. We analyze the effects of feed composition, relative volatility and product specification on the time requirements. The multivessel arrangements perform better than the regular batch column, which requires from 4.00 to 34.67% more time to complete a given separation. The elimination of the vapor bypass in the multivessel column is impractical though it has a positive effect on the batch time requirements. Thus, the multivessel column, with the vapor stream bypassing the intermediate vessel, is proposed as the best candidate for a binary zeotropic mixture with low concentration of light component, low relative volatility and high product purity demand. Furthermore, an experimental multivessel column with vapor bypass is built and the corresponding experiments verify the simulations.

3

Ocena stopnia segregacji mieszaniny w klasyfikatorze pneumatycznym

Zagaj I.

Zeszyty Naukowe. Mechanika / Politechnika Opolska

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2013

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z. 102

187-190

EN

This paper presents a test stand at which research was performed. Undertaken to determine the degree of segregation of the binary mixtures.

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Rozdział ciekłej mieszaniny dwuskładnikowej w procesie destylacji dyfuzyjnej w obecności inertów

Ziobrowski Z., Krupiczka R.

Przemysł Chemiczny

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2012

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T. 91, nr 7

1452-1456

PL

Przedstawiono wyniki badań doświadczalnych rozdziału mieszaniny 2-propanol–woda w zintegrowanym procesie odparowania i kondensacji przy spływie warstewki ciekłej w obecności inertów w fazie ciekłej i gazowej. Stwierdzono duży wpływ temperatury odparowania, rodzaju gazu inertnego oraz zawartości inertu w fazie ciekłej na wielkość strumieni masowych dyfundujących składników oraz selektywność rozdziału badanej mieszaniny. Opracowano model matematyczny procesu uwzględniający opory dyfuzyjne w fazie ciekłej i gazowej.

EN

Binary Me₂CHOH/H₂O mixt. was evapd. at 40–70°C in fulling film on vertical tube surface in presence of liq. and gaseous interts ((HOCH₂)₂ and air, Ar or He, resp.) and condensed on cooled tube surface to sep. the components of the mixt. The sepn. efficiency increased with increasing contents of (HOCH₂)₂ and Me₂CHOH in the liq. phase and increasing temp. of the phase. The math. model of the process was developed.

5

Positron study of the structure of nonadecane-tricosane mixed solid

Zgardzińska B., Goworek T.

Nukleonika

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2010

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Vol. 55, No. 1

47-49

EN

Positron annihilation lifetime and intensity were measured as a function of temperature for a binary mixture of two normal alkanes. The rotator phase is preceded by the range of about 7 K, in which one observes instability of spectrum parameters. In that range the mixed solid, being initially introduced into rotator phase, transforms to a rigid one in the time scale of several hours.

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Adsorption of Binary Mixtures of Organic (n-C6H12 or C6H5Cl) and Water Vapours on Activated Carbon U-03 at 293 K

Sobota R. M.

Polish Journal of Chemistry

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2008

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Vol. 82, nr 12

2309-2322

EN

The adsorption of vapour and liquid mixtures of H2O + c-C6H12 and H2O + C6H5Cl on activated carbon U-03 has been examined at room temperature 293 K. A model of Independent Co-adsorption proposed by Stoeckli et al. [1,2] leads to a good correlation between experimental and calculated mole fractions for each vapour in binary mixtures. This model can improve predicting dynamic systems such as break through curves and PSA (Pressure Swing Adsorption). This model shows Independent Co-adsorption which can describe static or dynamic systems including break through curves and PSA systems of binary immiscible vapour mixtures adsorbed by a typical industrial activated carbon U-03. The model assumes that vapours are adsorbed according to their respective Dubinin-Astakhov isotherms. A good mutual agreement was found between the calculated and experimental data.

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Mass diffusion in a binary mixture of viscous fluids confined between a rotating disk and a porous medium of finite thickness

Srivastava A. C., Srivastava P. K.

International Journal of Applied Mechanics and Engineering

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2008

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Vol. 13, no 4

1045-1057

EN

The diffusion effect in a binary mixture of incompressible viscous fluids confined between a rotating disk and a porous medium of finite thickness has been discussed. It is assumed that the lighter component is present in a small quantity. It is found that the pressure gradient created by the rotation of the disk in the free flow region separates the two components in the binary mixture in such a way that the concentration ratio of the lighter component decreases in both the regions. The concentration ratio of the lighter component in the porous medium is the maximum at the interface and then decreases sharply to zero indicating the boundary layer formation at the interface. This separative effect increases with the increase of the Darcy number, i.e., with the decrease of the permeability of the porous medium. These results are applicable for dispersion of fertilizers or other chemicals in an agricultural field.

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Unusual behaviour of binary mixtures of ferroelectric and antiferroelectric liquid crystals with three chiral centres

Glogarova M., Novotna V., Kaspar M., Hamplova V.

Opto-Electronics Review

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2002

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Vol. 10, No. 1

47-52

EN

Two binary mixtures have been studied of homologues from a series derived from 4-alkoxybiphenyl-4'-carboxylic acid with three chiral centres exhibiting ferroelectric (FE), antiferroelectric (AF) and tilted hexatic phases. One homologue exhibits a re-entrant SmC* (SmC*re) phase, which is miscible with the SmC* phase. The phase diagrams of the studied mixtures exhibit a close pocket of the SmC*A phase. The SmC*re phase is induced even in the mixtures composed of homologues without this phase. Dielectric spectroscopy reveals the Goldstone mode in both ferroelectric SmC* and the SmC*re phases, this mode being stroger when increasing concentration of the antiferroelectric homologue. In the SmC*A phase a relaxation mode is detected with the relaxation frequency three orders higher, which exhibits critical slowing down when approaching the SmC*re phase. This mode, which can be attributed to the anti - phase mode, is responsible for the apperance of SmC*re phase. In mixtures exhibiting the SmC*A phase a helix twist inversion occurs in the vinicity of the low temperature border of the AF phase.

9

Phase Separation of Binary Mixtures of Symmetric Non-Additive Hard Spheres

Góźdź M.

Polish Journal of Chemistry

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2001

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Vol. 75, nr 4

517-525

EN

The behavior of a binary mixture of non-additive hard spheres with positive nonadditivity parameter is investigated. The coexistence curves are calculated with a high accuracy for a few system sizes. The applicability of semigrand ensemble simulation method to calculation of the coexistence curve and the critical properties of mixtures is compared with other simulation method.