scholarly journals Nanostructured catalysts for BIOEthanol transformation to industrially important chemicals

2021 ◽  
Vol 14 (1) ◽  
pp. 66-78
Author(s):  
Blažej Horváth ◽  
Matúš Petrík ◽  
Dana Gašparovičová ◽  
Tomáš Soták
Keyword(s):  
Flow Reactor ◽  
Low Cost ◽  
Plug Flow ◽  
Value Added ◽  
Nanostructured Catalysts ◽  
Product Distribution ◽  
Catalytic Transformation ◽  
Basic Catalysts ◽  
Acid Catalyzed ◽  
The Impact

Abstract Utilization of a low-cost biomaterial, such as bioethanol, to produce value–added compounds for current industry has been investigated. This work is focused on the catalytic transformation of bioethanol into industrially significant alkenes. Catalytic transformation of ethanol was studied using catalysts based mainly on nanostructured materials as Mg-Al hydrotalcites, sepiolites and zeolites doped with Cu, K, Sr, Zn and Mn. The catalytic tests were carried out in a plug-flow reactor in the temperature range of 350—550 °C. Undoped zeolites promote acid-catalyzed dehydration of ethanol, while in case of basic catalysts, such as hydrotalcites, the product distribution is shifted toward butadiene. The impact of the hydrotalcites preparation method on their structure and catalytic activity is reported. It was found that hydrotalcite with well-developed layered structure, prepared by slow hydrolysis, promotes the formation of butadiene (with butadiene yield of 28.2 % at 400 °C vs. ethylene yield of 17.2 % at 550 °C).

scholarly journals Catalytic Hydrogenation, Hydrodeoxygenation, and Hydrocracking Processes of a Lignin Monomer Model Compound Eugenol over Magnetic Ru/C–Fe2O3 and Mechanistic Reaction Microkinetics

Catalysts ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 425 ◽  
Author(s):  
Ana Bjelić ◽  
Miha Grilc ◽  
Sašo Gyergyek ◽  
Andraž Kocjan ◽  
Darko Makovec ◽  
...  
Keyword(s):  
Model Compound ◽  
Annealing Temperature ◽  
Low Cost ◽  
Value Added ◽  
Product Distribution ◽  
Surface Chemical ◽  
Annealing Temperatures ◽  
Microkinetic Model ◽  
Highly Active ◽  
Commercial Carbon

Conversion of waste lignocellulosic (LC) biomass, a widely-available low-cost feedstock, into value-added biobased chemicals (and biofuels) has been gaining much attention recently. Therefore, the present lignin valorisation study was aimed at developing magnetically-separable highly-active catalysts for hydrodeoxygenation (HDO), also proposing surface chemical kinetics. Five carbonaceous substrate-deposited Ru were synthesised and tested for the HDO of monomer moiety eugenol. Their annealing temperatures differed, specifically between 300 and 750 °C, while one was not subjected to calcination. Experiments revealed the substantial influence of annealing temperature on the product distribution. Namely, fresh nonannealed nanocomposites were not active for hydrogenolysis. By further pretreatment increase, hydrogenation and, exclusively, the deoxygenation of saturated cyclic species, were enhanced, these being more promoted considering rates and yields than commercial carbon-supported ruthenium. Over 80 mol% of 4-propyl-cylohexanol and propyl-cyclohexane could be formed over the samples, treated at 500 and 600 °C, for 100 and 125 min, respectively, under 275 °C and 5 MPa of reactor hydrogen pressure. Interestingly, a notable 4-propyl-phenol amount was produced upon 750 °C pretreating. The intrinsic microkinetic model, developed previously, was applied to determine relevant turnover parameters. Calculated modelling results indicated a 47- and 10-fold greater demethoxylation and dehydroxylation mechanism ability upon the reheatingpreheating at 600 °C in comparison to industrial (heterogeneous) Ru/C.

Analysis of Equilibrium Shifting by Inter-Stage Reactant Feeding in a Series of Isothermal Reactors

2014 ◽  
Vol 12 (1) ◽  
pp. 163-179
Author(s):  
Florent Allain ◽  
Jean-François Portha ◽  
Laurent Falk
Keyword(s):  
Flow Reactor ◽  
Homogeneous Model ◽  
Plug Flow ◽  
Volumetric Flow Rate ◽  
Continuous Reactor ◽  
Two Stage ◽  
Heterogeneous Model ◽  
Number Systems ◽  
Reversible Reactions ◽  
The Impact

Abstract This paper focuses on the impact of reactant staging on conversion for one single reversible reaction in a two-stage, isothermal, continuous reactor. The analytical expression of global conversion has been derived for a series of two continuously stirred-tank reactors. Improvements in the overall conversion and yield by staging can be obtained for low Damköhler number systems leading to low conversions, when the volumetric flow rate of the staged reactant has a higher value than that of the other one. The example of triolein transesterification involving three reversible reactions in a two-stage plug flow reactor is also studied as a concrete example of a consecutive/parallel reversible reactions system. Results are obtained by using a pseudo-homogeneous model and are compared with those obtained with a heterogeneous model from a previous study.

scholarly journals Shopping tourism with a focus on the clothing industry in relation to globalization

2021 ◽  
Vol 92 ◽  
pp. 06030
Author(s):  
Tomáš Ric ◽  
Daniela Šálková
Keyword(s):  
Sustainable Development ◽  
Consumer Behaviour ◽  
Consumer Preferences ◽  
Negative Impact ◽  
Low Cost ◽  
Value Added ◽  
Clothing Industry ◽  
State Economy ◽  
Components Analysis ◽  
The Impact

Research background: The paper deals with the connections between international tourism and shopping, and therefore the purchase of clothing in relation to consumers. In the last few years, shopping has become one of the factors determining tourist’s decisions about choosing a travel destination. One-third of tourists have ever travelled just to buy clothes abroad. Such behaviour offers enormous economic potential for companies and the state economy. Shopping tourism is an integral part of globalization. Purpose of the article: The article’s aim is to characterize the elements of consumer behaviour in the framework of shopping tourism when buying clothing products. In addition to consumer preferences, the aim is to characterize the main types of clothing products that travellers are interested in and the impact of this consumer behaviour on the globalization. Methods: A questionnaire is compiled on the basis of stated hypotheses. The results will be evaluated using appropriate statistical methods such as the Kruskal-Wallis test, Spearman’s correlation coefficient and categorical principal components analysis. Findings & Value added: Research has shown that the first group of preferred garments consists of local products at a higher price level produced in low quantity. The second type of product is low-cost garments produced at a high cost under conditions that do not correspond to the principles of sustainable development. The clothing industry impact on global sustainable development is largely negative. In this regard, we can talk about the negative impact of globalization. This is no different from tourism.

scholarly journals Assessing point-of-use ultraviolet disinfection for safe water in urban developing communities

2014 ◽  
Vol 12 (4) ◽  
pp. 663-669 ◽  
Author(s):  
Christina K. Barstow ◽  
Aaron D. Dotson ◽  
Karl G. Linden
Keyword(s):  
Pathogenic Bacteria ◽  
Flow Reactor ◽  
Low Cost ◽  
Plug Flow ◽  
Field Testing ◽  
Low Flow ◽  
Health Concern ◽  
Log Reduction ◽  
Point Of Use ◽  
Developing Communities

Residents of urban developing communities often have a tap in their home providing treated and sometimes filtered water but its microbial quality cannot be guaranteed. Point-of-use (POU) disinfection systems can provide safe drinking water to the millions who lack access to clean water in urban communities. While many POU systems exist, there are several concerns that can lead to low user acceptability, including low flow rate, taste and odor issues, high cost, recontamination, and ineffectiveness at treating common pathogens. An ultraviolet (UV) POU system was constructed utilizing developing community-appropriate materials and simple construction techniques based around an inexpensive low-wattage, low pressure UV bulb. The system was tested at the bench scale to characterize its hydrodynamic properties and microbial disinfection efficacy. Hydraulically the system most closely resembled a plug flow reactor with minor short-circuiting. The system was challenge tested and validated for a UV fluence of 50 mJ/cm2 and greater, over varying flow rates and UV transmittances, corresponding to a greater than 4 log reduction of most pathogenic bacteria, viruses, and protozoa of public health concern. This study presents the designed system and testing results to demonstrate the potential architecture of a low-cost, open-source UV system for further prototyping and field-testing.

scholarly journals Oxygen Removal from a Hydrocarbon Containing Gas Stream by Plasma Catalysis

2021 ◽  
Vol 41 (2) ◽  
pp. 619-642
Author(s):  
T. Urbanietz ◽  
C. Stewig ◽  
M. Böke ◽  
A. von Keudell
Keyword(s):  
Conversion Efficiency ◽  
Plug Flow ◽  
Value Added ◽  
Reaction Products ◽  
Plasma Catalysis ◽  
Plasma Process ◽  
Manganese Oxide Catalyst ◽  
The Impact ◽  
Very High ◽  
Oxygen Atoms

AbstractHydrocarbon exhaust gases containing residual amounts of oxygen may pose challenges for their conversion into value added chemicals downstream, because oxygen may affect the process. This could be avoided by plasma treating the exhaust to convert $$\hbox {O}_2$$ O 2 in presence of hydrocarbons into CO or $$\hbox {CO}_2$$ CO 2 on demand. The underlying reaction mechanisms of plasma conversion of $$\hbox {O}_2$$ O 2 in the presence of hydrocarbons are analysed in a model experiment using a radio frequency atmospheric pressure helium plasma in a plug flow design with admixtures of $$\hbox {O}_2$$ O 2 and of $$\hbox {CH}_4$$ CH 4 . The plasma process is analysed with infrared absorption spectroscopy to monitor $$\hbox {CH}_4$$ CH 4 as well as the reaction products CO, $$\hbox {CO}_2$$ CO 2 and $$\hbox {H}_2$$ H 2 O. It is shown that the plasma reaction for oxygen (or methane removal) is triggered by the formation of oxygen atoms from $$\hbox {O}_2$$ O 2 by electron. Oxygen atoms are efficiently converted into CO, $$\hbox {CO}_2$$ CO 2 and $$\hbox {H}_2$$ H 2 O with CO being an intermediate in that reaction sequence. However, at very high oxygen admixtures to the gas stream, the conversion efficiency saturates because electron induced $$\hbox {O}_2$$ O 2 dissociation in the plasma seems to be counterbalanced by a reduction of the efficiency of electron heating at high admixtures of $$\hbox {O}_2$$ O 2 . The impact of a typical industrial manganese oxide catalyst is evaluated for methane conversion. It is shown that the conversion efficiency is enhanced by 15–20% already at temperatures of 430 K.

scholarly journals Impact of Chemistry–Turbulence Interaction Modeling Approach on the CFD Simulations of Entrained Flow Coal Gasification

Energies ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 6467
Author(s):  
Jakub Mularski ◽  
Norbert Modliński
Keyword(s):  
Gas Phase ◽  
Coal Gasification ◽  
Flow Reactor ◽  
Plug Flow ◽  
Interaction Model ◽  
Chemical Kinetic ◽  
Reaction Model ◽  
Phase Reaction ◽  
Entrained Flow ◽  
The Impact

This paper examines the impact of different chemistry–turbulence interaction approaches on the accuracy of simulations of coal gasification in entrained flow reactors. Infinitely fast chemistry is compared with the eddy dissipation concept considering the influence of turbulence on chemical reactions. Additionally, ideal plug flow reactor study and perfectly stirred reactor study are carried out to estimate the accuracy of chosen simplified chemical kinetic schemes in comparison with two detailed mechanisms. The most accurate global approach and the detailed one are further implemented in the computational fluid dynamics (CFD) code. Special attention is paid to the water–gas shift reaction, which is found to have the key impact on the final gas composition. Three different reactors are examined: a pilot-scale Mitsubishi Heavy Industries reactor, a laboratory-scale reactor at Brigham Young University and a Conoco-Philips E-gas reactor. The aim of this research was to assess the impact of gas phase reaction model accuracy on simulations of the entrained flow gasification process. The investigation covers the following issues: impact of the choice of gas phase kinetic reactions mechanism as well as influence of the turbulence–chemistry interaction model. The advanced turbulence–chemistry models with the complex kinetic mechanisms showed the best agreement with the experimental data.

Surface Modification of Nanocrystalline Zeolite X and Its Application as Catalyst in Synthesis of Cumene in a Packed Bed Flow Reactor: A Kinetic Study

2017 ◽  
Vol 16 (2) ◽  
Author(s):  
Ruchika Thakur ◽  
Sanghamitra Barman ◽  
Gopinath Halder
Keyword(s):  
Crystal Size ◽  
Flow Reactor ◽  
Plug Flow ◽  
Fixed Bed ◽  
Packed Bed ◽  
Product Distribution ◽  
Ceric Ammonium Nitrate ◽  
Zeolite X ◽  
Kinetic Rate ◽  
Nano Crystalline

AbstractIn the present investigation, synthesis of cumene by transalkylation of 1, 4 DIPB with benzene was studied over cerium modified nano crystalline zeolite X in a fixed bed plug flow reactor. Nano crystalline zeolite X was synthesized and characterized by XRD, SEM, TPD, EDS and FTIR. A series of nanocrystalline zeolite X (MX4, MX6, MX10) modified with ceric ammonium nitrate of different concentrations (4 %, 6 %, 10 %) was used for synthesis of cumene. MX10zeolite was proved to be the most active catalyst over which 27.12 % yield of cumene was obtained at temperature 553K, benzene/1, 4 DIPB mole ratio of 7.5 and space time-10.54 kg h/kmol. Reduction of crystal size (100–500 nm) in MX10increases surface area (633m2/gm) and thereby increases cumene yield. A kinetic rate equation was developed from the product distribution pattern following Langmuir–Hinshelwood approach. Kinetic parameters were estimated by nonlinear regression analysis. The activation energy for transalkylation and isomerisation reaction was found to be 88.86 kJ/mol and 99.04 kJ/mol respectively.

scholarly journals New Surface Properties in Porcelain Gres Tiles with a Look to Human and Environmental Safety

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
C. L. Bianchi ◽  
C. Pirola ◽  
S. Gatto ◽  
S. Nucci ◽  
A. Minguzzi ◽  
...  
Keyword(s):  
Gas Phase ◽  
Flow Reactor ◽  
Plug Flow ◽  
Environmental Safety ◽  
Photocatalytic Efficiency ◽  
Manufactured Products ◽  
New Generation ◽  
Digital Simulations ◽  
The Impact

Traditional photocatalysis is here brought forward for both the use of nanosized TiO2crystallites and the possibility to have a release of TiO2particles during the final use of the manufactured products. In the present paper both the preparation and characterization of a new generation of photocatalytic tiles are presented. The originality of these products is the surface presence of microsized TiO2as it is not clear yet the impact of the nanoparticles on both human and environmental safety. TiO2is here mixed with a silica compound and the final thermal treatment at 680°C allows the complete surface vitrification which, in turn, makes the tiles surface strongly resistant to abrasion. Photocatalytic efficiency towards the degradation ofNOxin gas phase was measured in both a batch and a plug-flow reactor. The latter reactor configuration was also modeled by digital simulations.

Computer simulation study about the dependence of amorphous silicon photonic waveguides efficiency on the material quality

2020 ◽  
Vol 90 (3) ◽  
pp. 30502
Author(s):  
Alessandro Fantoni ◽  
João Costa ◽  
Paulo Lourenço ◽  
Manuela Vieira
Keyword(s):  
Amorphous Silicon ◽  
High Throughput Screening ◽  
Simulation Analysis ◽  
Low Cost ◽  
Deposition Process ◽  
Large Area ◽  
Sidewall Roughness ◽  
Sensing Applications ◽  
Fabrication Defects ◽  
The Impact

Amorphous silicon PECVD photonic integrated devices are promising candidates for low cost sensing applications. This manuscript reports a simulation analysis about the impact on the overall efficiency caused by the lithography imperfections in the deposition process. The tolerance to the fabrication defects of a photonic sensor based on surface plasmonic resonance is analysed. The simulations are performed with FDTD and BPM algorithms. The device is a plasmonic interferometer composed by an a-Si:H waveguide covered by a thin gold layer. The sensing analysis is performed by equally splitting the input light into two arms, allowing the sensor to be calibrated by its reference arm. Two different 1 × 2 power splitter configurations are presented: a directional coupler and a multimode interference splitter. The waveguide sidewall roughness is considered as the major negative effect caused by deposition imperfections. The simulation results show that plasmonic effects can be excited in the interferometric waveguide structure, allowing a sensing device with enough sensitivity to support the functioning of a bio sensor for high throughput screening. In addition, the good tolerance to the waveguide wall roughness, points out the PECVD deposition technique as reliable method for the overall sensor system to be produced in a low-cost system. The large area deposition of photonics structures, allowed by the PECVD method, can be explored to design a multiplexed system for analysis of multiple biomarkers to further increase the tolerance to fabrication defects.

Use of thermomechanical pulp fibers from waste woods for making eco-friendly cushioning material

TAPPI Journal ◽  
2010 ◽  
Vol 9 (7) ◽  
pp. 15-21 ◽  
Author(s):  
JI-YOUNG LEE ◽  
CHUL-HWAN KIM ◽  
JEONG-MIN SEO ◽  
HO-KYUNG CHUNG ◽  
KYUNG-KIL BACK ◽  
...  
Keyword(s):  
Impact Test ◽  
Product Distribution ◽  
Expanded Polystyrene ◽  
Thermomechanical Pulp ◽  
Fiber Structure ◽  
Pulp Fibers ◽  
Cationic Starch ◽  
Thermal Insulating ◽  
Surface Sizing ◽  
The Impact

Eco-friendly cushioning materials were made with thermomechanical pulps (TMPs) from waste woods collected from local mountains in Korea, using a suction-forming method without physical pressing. The TMP cushions had superior shock-absorbing performance, with lower elastic moduli than expanded polystyrene (EPS) or molded pulp. Even though the TMP cushions made using various suction times had many voids in their inner fiber structure, their apparent densities were a little higher than that of EPS and much lower than that of molded pulp. The addition of cationic starch contributed to an increase in the elastic modulus of the TMP cushions without increasing the apparent density, an effect which was different from that of surface sizing with starch. In the impact test, the TMP cushions showed a more ductile pattern than the brittle EPS. The porosity of the TMP cushion was a little less than that of EPS and much greater than that of molded pulp. The porous structure of the TMP cushions contributed to their excellent thermal insulating capacity, which was equivalent to that of EPS. In summary, the TMP packing cushions showed great potential for surviving external impacts during product distribution.

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