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Abstract

The work concerns the dynamic behaviour of a porous, isothermal catalyst pellet in which a simultaneous chemical reaction, diffusion and adsorption take place. The impact of the reactant adsorption onto the pellet dynamics was evaluated. A linear isotherm and a non-linear Freundlich isotherm were considered. Responses of the pellet to sinusoidal variations of the reactant concentration in a bulk gas were examined. It was demonstrated that the dynamics of the pellet is significantly affected both by accounting for the adsorption and by the frequency of the bulk concentration variations. The sorption phenomenon causes damping of the concentration oscillations inside the pellet and damping of its effectiveness factor oscillations. Depending on the frequency of the concentration oscillations in the bulk, the remarkable oscillations can involve an entire volume of the pellet or its portion in the vicinity of the external surface.

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Authors and Affiliations

Katarzyna Bizon
Bolesław Tabiś
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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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Abstract

The main goal of the considered work is to adjust mathematical modeling for mass transfer, to specific conditions resulting from presence of chemical surface reactions in the flow of the mixture consisting of helium and methanol. The thermocatalytic devices used for decomposition of organic compounds incorporate microchannels coupled at the ends and heated to 500 ◦C at the walls regions. The experiment data were compared with computational fluid dynamics results to calibrate the constants of the model’s user defined functions. These extensions allow to transform the calculations mechanisms and algorithms of commercial codes adapting them for the microflows cases and increased chemical reactions rate on the interphase between fluid and solid, specific for catalytic reactions. Results obtained on the way of numerical calculations have been calibrated and compared with the experimental data to receive satisfactory compliance. The model has been verified and the performance of the thermocatalytic reactor with microchannels under hydrogen production regime has been investigated.

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Authors and Affiliations

Janusz Badur
Michał Stajnke
Paweł Ziółkowski
Paweł Jóźwik
Zbigniew Bojar
Piotr Józef Ziółkowski
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Abstract

Plastics are one of the most widely used materials, and, in most cases, they are designed to have long life spans. Since plastic and packaging waste pollute the environment for many years, their disposal is of great importance for the environment and human health. In this paper, a system was developed to store liquid fuel from plastic and organic waste mixes without solidification, which then can be used as fuel in motor vehicles and construction machinery. For this purpose, polyethylene terephthalate (PET), polyvinyl chloride (PVC), and organic wastes and clay, zeolite, and MCS23-code materials (50% magnetite- %25 calcium oxide- %25 sodium chloride) were heated in a closed medium at temperatures ranging from 300 to400 oC and subsequently re-condensed. The study conducted twenty tests, involving various types and rates of plastic and organic materials, as well as different rates of catalysts. Among these tests, the highest liquid fuel yield (67.47%) was achieved in Test 9, where 50% PVC-50% PET waste, 75 g of clinoptilolite, and 500 g of MCS23 waste were collectively used. Notably, Test 12 exhibited the highest density value (79.8 kg/m3), while the best viscosity value (2.794 mm2/s) was observed in Test 2. Across all samples, flash point values were found to be below 40oC. The most favorable yield point value was recorded in Test 2 (-6oC). The samples displayed ash content within the range of 0 to0.01% (m/m)] and combustion heat values of 35.000> J/g which fall within the standard range. The incorporation of MCS23 with clinoptilolite additives is believed to have a significant impact on obtaining high-yield products with improved fuel properties.
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Authors and Affiliations

Mehmet Can Sarıkap
1
Fatma Hoş Çebi
2
ORCID: ORCID

  1. İstanbul University-Cerrahpaşa, Turkey
  2. Karadeniz Technical University, Turkey
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Abstract

The advancement of contemporary internal combustion engine technologies necessitates not only design enhancements but also the exploration of alternative fuels or fuel catalysts. These endeavors are integral to curbing the emission of hazardous substances in exhaust gases. Most contemporary catalyst additives are of complex chemical origins, introduced into the fuel during the fuel preparation stage. Nonetheless, none of these additives yield a significant reduction in fuel consumption. The research endeavors to develop the fuel system of a primary marine diesel engine to facilitate the incorporation of pure hydrogen additives into diesel fuel. Notably, this study introduces a pioneering approach, employing compressed gaseous hydrogen up to 5 MPa as an additive to the principal diesel fuel. This method obviates the need for extensive modifications to the ship engine fuel equipment and is adaptable to modern marine power plants. With the introduction of modest quantities of hydrogen into the primary fuel, observable shifts in the behavior of the fuel equipment become apparent, aligning with the calculations outlined in the methodology. The innovative outcomes of the experimental study affirm that the mass consumption of hydrogen is contingent upon the hydrogen supply pressure, the settings of the fuel equipment, and the structural attributes of the fuel delivery system. The modulation of engine load exerts a particularly pronounced influence on the mass admixture of hydrogen. The proportion of mass addition of hydrogen in relation to the pressure of supply (ranging from 4–12 MPa) adheres to a geometric progression (within the range of 0.04–0.1%). The application of this technology allows for a reduction in the specific fuel consumption of the engine by 2–5%, contingent upon the type of fuel system in use, and concurrently permits an augmentation in engine power by up to 5%. The resultant economic benefits are estimated at 1.5–4.2% of the total fuel expenses. This technology is applicable across marine, automotive, tractor, and stationary diesel engines. Its implementation necessitates no intricate modifications to the engine design, and its utilization demands no specialized skills. It is worth noting that, in addition to hydrogen, other combustible gases can be employed.
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Authors and Affiliations

Denys Shalapko
1
Mykola Radchenko
1
Anatoliy Pavlenko
2
ORCID: ORCID
Roman Radchenko
1
Andrii Radchenko
1
Maxim Pyrysunko
1

  1. Admiral Makarov National University of Shipbuilding, Heroes of Ukraine Avenue 9, 54025 Mykolayiv, Ukraine
  2. Kielce University of Technology, Department of Building Physics and Renewable Energy, Aleja Tysia˛clecia Pan´stwa Polskiego 7,25-314, Kielce, Poland
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Abstract

The results of activity studies of four catalysts in methanol synthesis have been presented. A standard industrial catalyst TMC-3/1 was compared with two methanol catalysts promoted by the addition of magnesium and one promoted by zirconium. The kinetic analysis of the experimental results shows that the Cu/Zn/Al/Mg/1 catalyst was the least active. Although TMC-3/1 and Cu/Zn/Al/Mg/2 catalysts were characterised by a higher activity, the most active catalyst system was Cu/Zn/Al/Zr. The activity calculated for zirconium doped catalyst under operating conditions was approximately 30% higher that of TMC-3/1catalyst. The experimental data were used to identify the rate equations of two types - one purely empirical power rate equation and the other one - the Vanden Bussche & Froment kinetic model of methanol synthesis. The Cu/ZnO/Al2O3 catalyst modified with zirconium has the highest application potential in methanol synthesis.

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Authors and Affiliations

Stanisław Ledakowicz
Lech Nowicki
Jerzy Petera
Jarosław Nizioł
Paweł Kowalik
Andrzej Gołębiowski
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Abstract

Hydrogen (H2) and liquid petroleum gas (LPG) sensing properties of SnO2 thin films obtained by direct oxidation of chemically deposited SnS films has been studied. The SnS film was prepared by a chemical technique called SILAR (Successive Ionic Layer Adsorption and Reaction). The sensor element comprises of a layer of chemically deposited SnO2 film with an overlayer of palladium (Pd) sensitiser. The Pd sensitiser layer was also formed following a chemical technique. The double layer element so formed shows significantly high sensitivity to H2 and LPG. The temperature variation of sensitivity was studied and the maximum sensitivity of 99.7% was observed at around 200°C for 1 vol% H2 in air. The response time to target gas was about 10 seconds and the sensor element was found to recover to its original resistance reasonably fast. The maximum sensitivity of 98% for 1.6 vol% LPG was observed at around 325°C. The sensor response and recovery was reasonably fast (less than one minute) at this temperature.

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Authors and Affiliations

P. Mitra
S. Mondal
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Abstract

Methane (CH4) sensitivity of zinc oxide (ZnO) thin film has been studied in the present work. The sensor element comprises

of a chemically fabricated ZnO semiconducting layer and a layer of palladium (Pd) as catalyst. The catalyst layer was formed on the surface of semiconducting ZnO following a wet chemical process from palladium chloride (PdCl2) solution. Fundamental features of a sensor element e.g. sensitivity, response time and recovery process has been studied. The effect of operating temperature on performance of the sensor material has been investigated and a choice of optimum temperature was made at around 200oC. The sensor element exhibited reasonable sensitivity of about 86% at this temperature in presence of 1 vol% methane (CH4) in air.

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Authors and Affiliations

P. Mitra
A.K. Mukhopadhyay
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Abstract

The growing increase in the use of cars and transportation in general is causing an increase the emission of pollutants into the atmosphere. The current European Union regulations impose the minimization of pollution through the use of automotive catalytic converters on all member countries, which stops toxic compounds from being emitted into the atmosphere thanks to their contents of platinum group metals (PGMs). However, the growing demand for cars and the simultaneous demand for catalytic converters is contributing to the depletion of the primary sources of PGMs. This is why there is now increasing interest in recycling PGMs from catalytic converters through constantly developing technologies. There are newer and more sustainable solutions for the recovery of PGMs from catalytic converters, making the process part of a circular economy (CE) model. The purpose of this article is to present two innovative methods of PGM recovery in the framework of ongoing research and development projects.
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Authors and Affiliations

Natalia Generowicz
1
ORCID: ORCID
Agnieszka Nowaczek
1
ORCID: ORCID
Leszek Jurkowski
2
Iakovos Yakoumis
3

  1. Mineral and Energy Economy Research Institute Polish Academy of Sciences, Kraków, Poland
  2. Unimetal Recycling sp. z o.o., Trzebinia, Poland
  3. MONOLITHOS Catalysts and Recycling Ltd, Athens, Greece
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Abstract

Catalytic reforming is an important intermediate in the processing of crude (naphtha in particular) to obtain gasoline. The catalyst used in the process (platinum) is quite expensive and may negatively impact the business if not used judiciously. The aforesaid not only refers to the reduction in loss of the catalyst per unit of gasoline produced but also to the manufacturing of an environmentally friendlier product alongside which is the need of the planet and also a necessity to meet the increasingly strict government norms. In order to meet the above requirements, various refineries around the world use various well-known conventional methods which depend on the quality and quantity of crude manufactured by them.
This paper focuses on highlighting recent advancements in methods of catalytic regeneration (CR) in the reforming unit of petroleum industries to produce high octane gasoline, without any major replacements in their existing setup. Research papers formulated by the application of methodologies involving non-linear models and real-time refinery data have only been considered to avoid any deviations/errors in practical applications. In-depth analysis of these papers has led to the origin of some ideas which have been included as suggestions and can be considered as subjects of further research. In all, the objective of the paper is to serve as a reference for researchers and engineers working on devising optimum methods to improve the regeneration of reforming catalysts.
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Authors and Affiliations

Aviral Gupta
1
S.K. Gupta
1

  1. Harcourt Butler Technical University, Department of Chemical Engineering, Kanpur-208002, India
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Abstract

Kinetic studies of esterification reaction of maleic anhydride with butan-1-ol, 2-methylpropan-1-ol and butan-2-ol were carried out in a semibatch reactor, in the presence of four acidic catalysts: sulfuric acid, phosphotungstic acid, ion exchange resin Dowex 50WX8 and tetrabutyl zirconate. Phosphotungstic acid proved to be the most active catalyst. The temperature range was 383–413 K, the initial molar ratio of alcohol to acid ranged 2.2-5:1. The kinetic parameters were given. The kinetics appeared to be that of the second order with respect both to the acid and to the alcohol. The reaction carried out in the presence of tetrabutyl zirconate was very slow and depended only on acid concentration. The effect of temperature on the reaction rate follows the Arrhenius equation well.
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Authors and Affiliations

Maria Bartoszewicz
1
Maria Kulawska
2
Wiesław Organek
2

  1. Łukasiewicz Research Network – Institute of Heavy Organic Synthesis “Blachownia”, Energetyków 9, 47-225 Kędzierzyn-Koźle, Poland
  2. Polish Academy of Sciences, Institute of Chemical Engineering, Bałtycka 5, 44-100 Gliwice, Poland
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Abstract

Azo dye is widely used in the textile industry since it is cost effective and simple to use. However, it becomes a continuous source of environmental pollution due to its carcinogenicity and toxicity. Various methods had been used to remove the azo dye in solution. One of the famous and frequently used is the Fenton process. The Fenton process is one of the advanced oxidation processes where iron catalysed hydrogen peroxide to generate hydroxyl radical. Treating azo dyes in solution requires a catalyst to enhance the process of degradation. Herein, high entropy alloys (HEAs) have been proposed as a catalytic material to enhance the performance of Fenton process for azo dye degradation. HEAs have been reported as a promising catalyst due to its high surface area. The higher the number of active sites, the higher the rate of azo dye degradation as more active sites are available for adsorption of azo dyes. The results have shown that HEAs can be used as a catalyst to fasten the Fenton reaction since the degradation time is proven to be shorter in the presence of HEAs. The method derived from the result of this study will contribute in treating azo dyes for wastewater management in the Fenton process.
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Authors and Affiliations

N.H.A. Hassan
1
ORCID: ORCID
N.S.M. Nasir
1
ORCID: ORCID
S.N.A. Rahman
1
ORCID: ORCID
A.R. Irfan
2 3
ORCID: ORCID
N.H. Nordin
1
ORCID: ORCID

  1. International Islamic University Malaysia, Department of Manufacturing and Materials Engineering, Jalan Gombak, 53100 Kuala Lumpur, Malaysia
  2. Universiti Malaysia Perlis, Faculty of Mechanical Engineering Technology, Perlis, Malaysia
  3. Universiti Malaysia Perlis, Center of Excellence Geopolymer and Green Technology (CEGeoGTech), Perlis, Malaysia
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Abstract

This paper presents the results of investigations into dry methane reforming (DMR). The process was aimed at obtaining synthesis gas required for the production of dimethyl ether (DME). The effect of temperature, pressure and inlet gas composition on the process was determined in the experimental part of this work. The tests were carried out in a laboratory tubular reactor over a Ni/CaO–Al2O3 catalyst. The obtained experimental results were used to verify literature kinetic data and to develop a mathematical model of the DMR process.
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Authors and Affiliations

Robert Cherbański
1
ORCID: ORCID
Ewelina Franczyk
2
Michał Lewak
1
Piotr Machniewski
1
Eugeniusz Molga
1
ORCID: ORCID

  1. Warsaw University of Technology, Faculty of Chemical and Process Engineering, ul. Warynskiego 1, 00-645 Warsaw, Poland
  2. Łukasiewicz Research Network – New Chemical Syntheses Institute, Al. Tysiaclecia Panstwa Polskiego 13a, 24-110 Puławy, Poland
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Abstract

Mordenite-zeolite supported Ca-Cu and Ba-Cu catalysts (Ca-Cu/MOR and Ba-Cu MOR) were successfully fabricated for direct decomposition of both NF3 and N2O gases contained in waste gas stream of (semiconductor) electronics industry. N2O conversion rates of Ca-Cu and Ba-Cu catalysts were 79 and 86%, respectively, at 700°C and 1 atm under space velocity of 5000 h–1. The Ca-Cu catalyst was especially noteworthy in that its capability of converting N2O could be maintained even after its exposure to co-feeding NF3 gas constituent in the waste gas stream. Compositional and surface morphological analyses of the Ca-Cu and Ba-Cu catalysts were made before and after exposure to the waste gas stream to examine any noticeable degradation or change of the catalysts. Unlike Ba-Cu catalyst, SiO2 constituent of the Ca-Cu catalyst was found to remain immune to the NF3-cofeeding waste gas stream, casting a positive prospect for superior and steady N2O decomposition performance via maintenance of its structural integrity.

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Authors and Affiliations

Minhye Seo
Soo-Young Lee
Sung-Su Cho
Hyoung Woon Song
Hyun-Kyung Kim
Dong Soo Kim
Sungkyu Lee
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Abstract

Semiconductive - resistive sensors of toxic and explosive gases were fabricated from nanograins of SnO2 using thick-.lm technology. Sensitivity, selectivityand stabilityof sensors working in di.erent temperature depend on the way the tin dioxide and additives were prepared. A construction also plays an important role. The paper presents an attitude towards the evaluation of transport of electrical charges in semiconductive grain layer of SnO2, when dangerous gases appear in the surrounding atmosphere.

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Authors and Affiliations

B. Licznerski
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Abstract

A detailed comparison of catalytic properties of two different ruthenium-based catalysts in the reaction of homogeneous hydrogenation of acetophenone was performed. Additionally, methods of synthesis of both catalysts were tested and optimized in order to achieve the best possible quality and purity of the final catalysts.

NMR analysis was used to analyze and identify the composition of ruthenium compounds and gas chromatography was used to analyze the conversion rate of hydrogenation reactions.

It was determined that RuCl2(PPh3)3 obtained with a modified method described by Shaw’s group (Shawet al., 2007) had the best catalytic properties in the reaction performed under conditions described in Liang Wang’s publication (Wang et al., 2014). It was also determined that for concentration ratio of substrate to RuCl2(PPh3)3 amounting to 250:1 the conversion rate was much higher than that of the reaction performed with a double dose of the catalyst. Results of experiments also show that samples of the post-reaction solution should be analyzed right after the reaction, because even if they are stored in low temperature the amount of product can change up to 3–5% compared to the base sample and this change is not predictable.

These findings have significant implications for further research of the reaction of homogeneous transfer hydrogenation of ketones. With the right catalysts and methods of their synthesis other parameters of this reaction can be optimized. The most important one is a change of solvent from isopropyl alcohol to a less toxic substance like water. This may increase the value of the reaction in green chemistry and chemical industry.

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Authors and Affiliations

Filip Mikołajczyk
Kamil Kamiński
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Abstract

The study evaluated the curing properties of natural silica sand moulded with 1% by weight Furotec 132 resin binder catalysed by Furocure CH Fast acid and Furocure CH Slow acid. Physical properties of this sand included an AFS number of 47.35, 4.40 % clay, 0 % magnetic components, 0.13 % moisture, and 64.5 % of the size distribution spread over three consecutive sieves (150 – 600 μm). The sand was washed repeatedly to remove all the clay and oven dried. 2 kg washed sand samples were mulled with pre-determined weights of either catalyst to give 30 %, 50 % and 70 % by weight of 20 g Furotec 132 resin which was added last. Furotec 132 resin + Furocure CH Slow acid catalyst system gives longer bench lives and strip times but the maximum compressive strength in excess of 5000 N/cm2 is attained after more than 8.5 hours curing time irrespective of the weight % of catalyst added relative to the resin. On that basis, exceeding 30 weight % Furocure CH Slow acid catalyst when sand moulding with Furotec 132 resin has neither technical nor economic justification. In comparison, the Furotec 132 resin + Furocure CH Fast acid catalyst system was only capable of producing mould specimens with maximum compressive strength above 5000 N/cm2 at 30 weight % catalyst addition rate. At 50 and 70 weight % catalyst addition rates, the mulled sand rapidly turned dark green then bluish with a significant spike in temperature to about 40 oC, far exceeding the optimum curing temperature of Furotec 132. This high temperature accelerates the curing rate but with a very low degree of resin curing which explains the low compressive strength. In fact the sand grains fail to bond and have a dry, crumbly texture implying dehydration. Thus, not more than 30 weight % Furocure CH Fast acid catalyst should be used in sand moulding.

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Authors and Affiliations

M.M. Mashingaidze

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