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Number of results: 6
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Abstract

Preparation and properties of hierarchically structured porous silica monoliths have been discussed from the viewpoint of their application as continuous microreactors for liquid-phase synthesis of fine chemical in multi kilogram scales. The results of recent topical papers published by two research teams of Institute of Chemical Engineering Polish Academy of Sciences (ICE) and Department of Chemical Engineering and Process Design, Chemical Faculty, Silesian University of Technology (SUT) have been analyzed to specify the governing traits of microreactors. It was concluded that even enhancement factor of 100 in activity, seen in enzyme catalyzed reactions, can be explained by a proportional reduction of its physical constraints, i.e. huge enhancement of external mass transfer and micromixing. It is induced by very chaotic flows of liquid in tens of thousands of waving connected channels of ca. 25–50 mm in diameter, present in the skeleton. The scale of enhancement in the case of less active catalysts was smaller, but still large enough to consider the most practical applications.

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Authors and Affiliations

Julita Mrowiec-Białoń
Agnieszka Ciemięga
Katarzyna Maresz
Katarzyna Szymańska
Wojciech Pudło
Andrzej B. Jarzębski
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Abstract

A novel absorbing pervaporation hybrid technique has been evaluated experimentally for the recovery of ammonia from the gas mixture in a recycle loop of synthesis plants. This process of hybridization brings together the combination of energy-efficient membrane gas separation based on poly(dimethylsiloxane) poly(diphenylsilsesquioxane) with a high selective sorption technique where a water solution with polyethylene glycol 400 (PEG-400) was used as the liquid absorbent. Process efficiency was studied using the pure and mixed gases. The influence of PEG-400 content in aqueous solutions on process selectivity and separation efficiency was studied. The ammonia recovery efficiency evaluation of an absorbing pervaporation technique was performed and compared with the conventional membrane gas separation. It was shown that the absorbing pervaporation technique outperforms the conventional membrane method in the whole range of productivity, producing the ammonia with a purity of 99.93 vol.% using the PEG 80 wt.% solution. The proposed method may be considered as an attractive solution in the optimization of the Haber process.

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Authors and Affiliations

Artem A. Atlaskin
Anton N. Petukhov
Nail R. Yanbikov
Maria E. Salnikova
Maria S. Sergeeva
Vladimir M. Vorotyntsev
Ilya V. Vorotyntsev
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Abstract

The main aim of this work is to study the thermal efficiency of a new type of a static mixer and to analyse the flow and temperature patterns and heat transfer efficiency. The measurements were carried out for the static mixer equipped with a new mixing insert. The heat transfer enhancement was determined by measuring the temperature profiles on each side of the heating pipe as well as the temperature field inside the static mixer. All experiments were carried out with varying operating parameters for four liquids: water, glycerol, transformer oil and an aqueous solution of molasses. Numerical CFD simulations were carried out using the two-equation turbulence k-ω model, provided by ANSYS Workbench 14.5 software. The proposed CFD model was validated by comparing the predicted numerical results against experimental thermal database obtained from the investigations. Local and global convective heat transfer coefficients and Nusselt numbers were detrmined. The relationship between heat transfer process and hydrodynamics in the static mixer was also presented. Moreover, a comparison of the thermal performance between the tested static mixer and a conventional empty tube was carried out. The relative enhancement of heat transfer was characterised by the rate of relative heat transfer intensification.

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Authors and Affiliations

Maciej Konopacki
Marian Kordas
Karol Fijałkowski
Rafał Rakoczy
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Abstract

The paper presents the experimental study of a novel unsteady-statemembrane gas separation approach for recovery of a slow-permeant component in the membrane module with periodical retentate withdrawals. The case study consisted in the separation of binary test mixtures based on the fast-permeant main component (N2O, C2H2) and the slow-permeant impurity (1%vol. of N2) using a radial countercurrent membrane module. The novel semi-batch withdrawal technique was shown to intensify the separation process and provide up to 40% increase in separation efficiency compared to a steady-state operation of the same productivity.

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Authors and Affiliations

Stanislav V. Battalov
Maxim M. Trubyanov
Egor S. Puzanov
Tatyana S. Sazanova
Pavel N. Drozdov
Ilya V. Vorotyntsev
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Abstract

Humic acids (HAs) are components of natural organic matter found in soil and are considered responsible for its fertility. They can be extracted from sources such as peat and lignite on an industrial scale. In order to increase the efficiency and reduce the duration of the alkaline extraction step, microwave-assisted extraction (MAE) was used in this study. Statistical analysis was implemented to describe the influence of microwave power, temperature, and time on the yield of HA extraction. Experimental points were created on the basis of the matrix, according to the Box-Behnken design. Statistical analysis showed the importance of linear correlations between the process parameters and the response. The last part of the presented study was to create the polynomial model and response surface plots, attached in poster form, which describe the result as a function of parameters of the MAE process.
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Authors and Affiliations

Kinga M. Marecka
1
ORCID: ORCID
Dominik Nieweś
1
ORCID: ORCID
Magdalena Braun-Giwerska
1
ORCID: ORCID
Marta Huculak-Mączka
1
ORCID: ORCID

  1. Wrocław University of Science and Technology, Department of Chemical Process Engineering and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland
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Abstract

A proper selection of steam reforming catalyst geometry has a direct effect on the efficiency and economy of hydrogen production from natural gas and is a very important technological and engineering issue in terms of process optimisation. This paper determines the influence of widely used seven-hole grain diameter (ranging from 11 to 21 mm), h/d (height/diameter) ratio of catalyst grain and Sh/St (hole surface/total cylinder surface in cross-section) ratio (ranging from 0.13 to 0.37) on the gas load of catalyst bed, gas flow resistance, maximum wall temperature and the risk of catalyst coking. Calculations were based on the one-dimensional pseudo-homogeneous model of a steam reforming tubular reactor, with catalyst parameters derived from our investigations. The process analysis shows that it is advantageous, along the whole reformer tube length, to apply catalyst forms of h/d = 1 ratio, relatively large dimensions, possibly high bed porosity and Sh/St ≈ 0.30-0.37 ratio. It enables a considerable process intensification and the processing of more natural gas at the same flow resistance, despite lower bed activity, without catalyst coking risk. Alternatively, plant pressure drop can be reduced maintaining the same gas load, which translates directly into diminishing the operating costs as a result of lowering power consumption for gas compression.

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Authors and Affiliations

Ewelina Franczyk
Andrzej Gołębiowski
Tadeusz Borowiecki
Paweł Kowalik
Waldemar Wróbel

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