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ChemEngineering, Volume 2, Issue 3 (September 2018)

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Cover Story (view full-size image) Well-defined structural and textural properties of solids for industrial applications are essential [...] Read more.
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Open AccessArticle Novel formation of Ferrite in Ingot of 0Cr17Ni4Cu4Nb Stainless Steel
ChemEngineering 2018, 2(3), 44; https://doi.org/10.3390/chemengineering2030044
Received: 1 August 2018 / Revised: 23 August 2018 / Accepted: 5 September 2018 / Published: 10 September 2018
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Abstract
The ferrite body is the origin of crack and corrosion initiation of steels. Distribution and density of ferrite in seven steel ingots were examined by light optical microscopy and computational modeling, in the study, to explore the correlation of ferrite formation to chemical
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The ferrite body is the origin of crack and corrosion initiation of steels. Distribution and density of ferrite in seven steel ingots were examined by light optical microscopy and computational modeling, in the study, to explore the correlation of ferrite formation to chemical composition and the mushy zone temperature in ingot forming. The central segregation phenomenon in ferrite distribution was observed in all the examined steel specimens, except 0Cr17Ni4Cu4Nb stainless steel. No significant difference was found in the distribution and density of ferrite among zones of the surface, ½ radius, and core in neither the risers nor tails of 0Cr17Ni4Cu4Nb ingots. Additionally, fewer ferrites were found in 0Cr17Ni4Cu4Nb compared to other examined steels. The difference of ferrite formation in 0Cr17Ni4Cu4Nb elicited a debate on the traditional models explicating ferrite formation. Considering the compelling advantages in mechanical strength, plasticity, and corrosion resistance, further investigation on the unusual ferrite formation in 0Cr17Ni4Cu4Nb would help understand the mechanism to improve steel quality. In summary, we observed that ferrite formation in steel was correlated with the mushy zone temperature. The advantages of 0Crl7Ni4Cu4Nb in corrosion resistance and mechanical stability could be the result of fewer ferrites being formed and distributed in a scattered manner in the microstructure of the steel. Full article
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Open AccessArticle Alternative of Biogas Injection into the Danish Gas Grid System—A Study from Demand Perspective
ChemEngineering 2018, 2(3), 43; https://doi.org/10.3390/chemengineering2030043
Received: 8 August 2018 / Revised: 27 August 2018 / Accepted: 3 September 2018 / Published: 5 September 2018
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Abstract
The Danish government has set an ambitious target to achieve 100% fossil independence across all energy sectors, which demands optimum utilization of renewable energy sources, such as wind and biogas, by 2050. Biogas production has increased, and the upgrading of biogas offers a
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The Danish government has set an ambitious target to achieve 100% fossil independence across all energy sectors, which demands optimum utilization of renewable energy sources, such as wind and biogas, by 2050. Biogas production has increased, and the upgrading of biogas offers a broad range of applications, such as transportation, and gas grid injection for downstream utilization. The biogas has to meet natural gas quality prior to injection into the gas grid system. The investment costs of the gas grid, upgrading cost, and gas compression costs are the major challenges for integrating the biogas into the existing gas infrastructure. In this investigation, the Wobbe index (WI) for raw biogas and upgraded biogas was measured to evaluate the scenario for biogas injection into the gas grid system. It was found that raw biogas has to improve its WI from 28.3 MJ/m3(n) to a minimum of 50.76 MJ/m3(n) via upgrading, and compressed to 40 bar system, to supply the gas grid system for trading. Then, yearly gas consumption by larger gas consumers was studied to evaluate the alternative approach of biogas utilization to save upgrading and compression costs for gas grid injection. Full article
(This article belongs to the Special Issue Advances in Bio-Fuels Production)
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Open AccessReview Solar Fuels by Heterogeneous Photocatalysis: From Understanding Chemical Bases to Process Development
ChemEngineering 2018, 2(3), 42; https://doi.org/10.3390/chemengineering2030042
Received: 30 July 2018 / Revised: 27 August 2018 / Accepted: 30 August 2018 / Published: 4 September 2018
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Abstract
The development of sustainable yet efficient technologies to store solar light into high energy molecules, such as hydrocarbons and hydrogen, is a pivotal challenge in 21st century society. In the field of photocatalysis, a wide variety of chemical routes can be pursued to
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The development of sustainable yet efficient technologies to store solar light into high energy molecules, such as hydrocarbons and hydrogen, is a pivotal challenge in 21st century society. In the field of photocatalysis, a wide variety of chemical routes can be pursued to obtain solar fuels but the two most promising are carbon dioxide photoreduction and photoreforming of biomass-derived substrates. Despite their great potentialities, these technologies still need to be improved to represent a reliable alternative to traditional fuels, in terms of both catalyst design and photoreactor engineering. This review highlights the chemical fundamentals of different photocatalytic reactions for solar fuels production and provides a mechanistic insight on proposed reaction pathways. Also, possible cutting-edge strategies to obtain solar fuels are reported, focusing on how the chemical bases of the investigated reaction affect experimental choices. Full article
(This article belongs to the Special Issue Heterogeneous Photocatalysis and Photocatalytic Nanomaterials)
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Open AccessArticle Implementation, Design and Cost Assessment of a Membrane-Based Process for Selectively Enriching Desalinated Water with Divalent Seawater Ions
ChemEngineering 2018, 2(3), 41; https://doi.org/10.3390/chemengineering2030041
Received: 7 August 2018 / Revised: 27 August 2018 / Accepted: 3 September 2018 / Published: 3 September 2018
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Abstract
The paper describes results from operating a new 3-step membrane-based process targeted at separating Mg2+ from seawater in an inexpensive way, with the purpose of using it to enrich desalinated water with magnesium, with as little as possible Cl and Na
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The paper describes results from operating a new 3-step membrane-based process targeted at separating Mg2+ from seawater in an inexpensive way, with the purpose of using it to enrich desalinated water with magnesium, with as little as possible Cl and Na+ addition. To this end, seawater undergoes a series of processes aimed at increasing the Mg2+ concentration from ~1350 to ~4000 mg/L through nanofiltration while the monovalent ion concentrations are reduced by a nanofiltration-diananofiltration sequence, in which the diluent is RO produced water from a desalination plant. A dense ultrafiltration (UF) step precedes the nanofiltration-diananofiltration (NF-DiaNF) cycles. In this step sulfate in seawater is rejected better than divalent cations hence the retentate of this step has a ratio of total hardness to sulfate (([Ca2+] + [Mg2+])/[SO42−] → 1) which enables attaining an almost complete washout of monovalent ions in the DiaNF step. The paper is concluded with presentation of general design of the process steps and a cost assessment, which shows the process to be both flexible in the quality of the rich Mg solution generated, and cost competitive, relative to other alternatives. Full article
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Open AccessArticle Photodegradation of Stearic Acid Adsorbed on Copper Oxide Heterojunction Thin Films Prepared by Magnetron Sputtering
ChemEngineering 2018, 2(3), 40; https://doi.org/10.3390/chemengineering2030040
Received: 11 August 2018 / Revised: 23 August 2018 / Accepted: 24 August 2018 / Published: 28 August 2018
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Abstract
Nanocrystalline copper oxide thin films were fabricated by reactive DC magnetron sputtering. The structure and optical properties of the films were measured with X-ray diffraction, scanning electron microscopy, and spectrophotometry. Variations of oxygen partial pressure resulted in oxide composition ranging from Cu, Cu-Cu
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Nanocrystalline copper oxide thin films were fabricated by reactive DC magnetron sputtering. The structure and optical properties of the films were measured with X-ray diffraction, scanning electron microscopy, and spectrophotometry. Variations of oxygen partial pressure resulted in oxide composition ranging from Cu, Cu-Cu2O, Cu2O-CuO1−x, and CuO. Optical band transitions at 2.06 eV and 2.55 eV were found for Cu2O corresponding to the direct forbidden and direct allowed interband transitions. For CuO an indirect allowed interband transition was found at 1.28 eV. The photocatalytic activity was determined by quantifying the rate constant and quantum yield (destroyed molecules/photons absorbed) under stearic acid degradation. Photocatalytic activity was found to be highest in mixed-phase films with Cu-Cu2O films the highest. Results from post-annealed Cu-Cu2O and CuO films show similar results. We interpret our results as being due to efficient electron-hole charge separation in the heterojunction films. The obtained quantum yields were generally about ten times lower than for comparable dense TiO2 and WO3 binary oxides, which calls for further studies of the spectral dependence of the quantum yield and electron-hole pair life times for oxides with different purity levels. Full article
(This article belongs to the Special Issue Heterogeneous Photocatalysis and Photocatalytic Nanomaterials)
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Open AccessArticle Euler–Lagrange Modeling of Bubbles Formation in Supersaturated Water
ChemEngineering 2018, 2(3), 39; https://doi.org/10.3390/chemengineering2030039
Received: 3 May 2018 / Revised: 15 August 2018 / Accepted: 22 August 2018 / Published: 24 August 2018
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Abstract
Phase transition, and more specifically bubble formation, plays an important role in many industrial applications, where bubbles are formed as a consequence of reaction such as in electrolytic processes or fermentation. Predictive tools, such as numerical models, are thus required to study, design
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Phase transition, and more specifically bubble formation, plays an important role in many industrial applications, where bubbles are formed as a consequence of reaction such as in electrolytic processes or fermentation. Predictive tools, such as numerical models, are thus required to study, design or optimize these processes. This paper aims at providing a meso-scale modelling description of gas–liquid bubbly flows including heterogeneous bubble nucleation using a Discrete Bubble Model (DBM), which tracks each bubble individually and which has been extended to include phase transition. The model is able to initialize gas pockets (as spherical bubbles) representing randomly generated conical nucleation sites, which can host, grow and detach a bubble. To demonstrate its capabilities, the model was used to study the formation of bubbles on a surface as a result of supersaturation. A higher supersaturation results in a faster rate of nucleation, which means more bubbles in the column. A clear depletion effect could be observed during the initial growth of the bubbles, due to insufficient mixing. Full article
(This article belongs to the Special Issue Bubble Column Fluid Dynamics)
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Open AccessReview Greenhouse Gas Sensors Fabricated with New Materials for Climatic Usage: A Review
ChemEngineering 2018, 2(3), 38; https://doi.org/10.3390/chemengineering2030038
Received: 29 June 2018 / Revised: 20 July 2018 / Accepted: 9 August 2018 / Published: 24 August 2018
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Abstract
With the increasing utilization of fossil fuels in today’s technological world, the atmosphere’s concentration of greenhouse gases is increasing and needs to be controlled. In order to achieve this goal, it is imperative to have sensors that can provide data on the greenhouse
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With the increasing utilization of fossil fuels in today’s technological world, the atmosphere’s concentration of greenhouse gases is increasing and needs to be controlled. In order to achieve this goal, it is imperative to have sensors that can provide data on the greenhouse gases in the environment. The recent literature contains a few publications that detail the use of new methods and materials for sensing these gases. The first part of this review is focused on the possible effects of greenhouse gases in the atmosphere, and the second part surveys the developments of sensors for greenhouse gases with coverage on carbon nano-materials and composites directed towards sensing gases like CO2, CH4, and NOx. With carbon dioxide measurements, due consideration is given to the dissolved carbon dioxide gas in water (moisture). The density functional calculations project that Pd-doped single-walled carbon nanotubes are ideal for the development of NOx sensors. The current trend is to make sensors using 3D printing or inkjet printing in order to allow for the achievement of ppb levels of sensitivity that have not been realized before. This review is to elaborate on the need for the development of greenhouse gas sensors for climatic usage by using selected examples. Full article
(This article belongs to the Special Issue Carbon-Based Materials and Their Electrochemical Applications)
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Open AccessArticle Removal of the Recalcitrant Artificial Sweetener Sucralose and Its By-Products from Industrial Wastewater Using Microbial Reduction/Oxidation of Iron
ChemEngineering 2018, 2(3), 37; https://doi.org/10.3390/chemengineering2030037
Received: 16 July 2018 / Revised: 4 August 2018 / Accepted: 15 August 2018 / Published: 18 August 2018
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Abstract
The wastewater of the industrial production of artificial sweetener sucralose contained an average 1100 mg/L of total organic carbon (TOC) with 2100 mg/L of chemical oxygen demand and 10 mg/L of biological oxygen demand. Biodegradability of the wastewater components was low due to
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The wastewater of the industrial production of artificial sweetener sucralose contained an average 1100 mg/L of total organic carbon (TOC) with 2100 mg/L of chemical oxygen demand and 10 mg/L of biological oxygen demand. Biodegradability of the wastewater components was low due to chlorinated organic substances. The combined chemical and biological treatment of this wastewater in the bioreactors with hematite iron ore removed up to 70% of TOC. About 20% of TOC was removed quickly by adsorption on iron ore particles, but adsorption/precipitation of others up to 50% of TOC was due to ferrous/ferric ions and hydroxides produced during microbial reduction and dissolution of iron ore. The calculated dosage of iron ore with 150 regeneration cycles could be 46.7 g/L of wastewater. Thus, the treatment of wastewater with iron ore and iron-reducing bacteria diminished the quantity of granulated activated carbon that is used in the treatment of sucralose production wastewater by up to 70%. Full article
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Open AccessReview Development of Sunlight Driven Water Splitting Devices towards Future Artificial Photosynthetic Industry
ChemEngineering 2018, 2(3), 36; https://doi.org/10.3390/chemengineering2030036
Received: 1 July 2018 / Revised: 7 August 2018 / Accepted: 9 August 2018 / Published: 13 August 2018
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Abstract
The ongoing research and development of sunlight-driven water splitting in the “Japan Technological Research Association of Artificial Photosynthetic Chemical Process (ARPChem)” is overviewed. Water splitting photocatalysts, photoelectrochemical devices, large-scale reactor panels, product gas transportation, H2/O2 gas separation devices and safety
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The ongoing research and development of sunlight-driven water splitting in the “Japan Technological Research Association of Artificial Photosynthetic Chemical Process (ARPChem)” is overviewed. Water splitting photocatalysts, photoelectrochemical devices, large-scale reactor panels, product gas transportation, H2/O2 gas separation devices and safety measures against explosion are included as the research objectives. ARPChem was formed as a research union of Japan’s leading chemical firms, in which related elementary technologies have been cultivated. This article introduces our general scope for artificial photosynthesis and describes present research activities, mainly on solar driven water splitting photocatalysts/photoelectrodes and briefly on the processes and plans for plant construction for future industrial extension. Full article
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Open AccessArticle Evaluation of Cd(II) Ion Removal from Aqueous Solution by a Low-Cost Adsorbent Prepared from White Yam (Dioscorea rotundata) Waste Using Batch Sorption
ChemEngineering 2018, 2(3), 35; https://doi.org/10.3390/chemengineering2030035
Received: 2 April 2018 / Revised: 12 June 2018 / Accepted: 21 June 2018 / Published: 3 August 2018
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Abstract
An agricultural residue, white yam (Dioscorea rotundata) tuber peel (YTBS), was used for the removal of Cd(II) ion from an aqueous solution using a batch method. The adsorbent was characterized using FTIR, TGA, SEM, EDX, N2 BET, XRD, and XRF.
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An agricultural residue, white yam (Dioscorea rotundata) tuber peel (YTBS), was used for the removal of Cd(II) ion from an aqueous solution using a batch method. The adsorbent was characterized using FTIR, TGA, SEM, EDX, N2 BET, XRD, and XRF. The optimization of sorption variables such as pH, contact time, adsorbent dose, and initial metal ion concentration at 25 °C were also carried out. The results indicated the dependence of sorption on the adsorbate pH and adsorbent dose, while the adsorption system reached equilibrium in 180 min. The sorption kinetics was fitted to three models (pseudo first order, pseudo second order, and Elovich) to validate the kinetics, and the pseudo first order was the best model for the description of Cd(II) uptake. Equilibrium isotherm modelling was also carried out using the Langmuir, Freundlich, and Temkin models, with the Langmuir isotherm giving the best fitting to the experimental results. The maximum loading capacity (qmax) of the adsorbent for Cd(II) obtained from the Langmuir isotherm model was 22.4 mg∙g−1 with an isotherm constant (KL) of 3.46 × 10−3 L·mg−1 and r2 value of 0.99. This result indicates that the YTBS residue was a good adsorbent for the removal of Cd(II) ion from aqueous system. Full article
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Open AccessArticle CFD Simulation of Ethanol Steam Reforming System for Hydrogen Production
ChemEngineering 2018, 2(3), 34; https://doi.org/10.3390/chemengineering2030034
Received: 26 May 2018 / Revised: 26 July 2018 / Accepted: 30 July 2018 / Published: 2 August 2018
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Abstract
Hydrogen could be a promising source fuel, and is often considered as a clean energy carrier as it can be produced by ethanol. The use of ethanol presents several advantages, because it is a renewable feedstock, easy to transport, biodegradable, has low toxicity,
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Hydrogen could be a promising source fuel, and is often considered as a clean energy carrier as it can be produced by ethanol. The use of ethanol presents several advantages, because it is a renewable feedstock, easy to transport, biodegradable, has low toxicity, contains high hydrogen content, and easy to store and handle. Reforming ethanol steam occurs at relatively lower temperatures, compared with other hydrocarbon fuels, and has been widely studied due to the high yield provided for the formation of hydrogen. A new computational fluid dynamics (CFD) simulation model of the ethanol steam reforming (ESR) has been developed in this work. The reforming system model is composed from an ethanol burner and a catalytic bed reactor. The liquid ethanol is burned inside the firebox, then the radiative heat flux from burner is transferred to the catalytic bed reactor for transforming the ethanol steam mixture to hydrogen and carbon dioxide. The proposed computational model is composed of two phases—Simulation of ethanol burner by using Fire Dynamics Simulator software (FDS) (version 5.0) and a multi-physics simulation of the steam reforming process occurring inside the reformer. COMSOL multi-physics software (version 4.3b) has been applied in this work. It solves simultaneously the fluid flow, heat transfer, diffusion with chemical reaction kinetics equations, and structural analysis. It is shown that the heat release rate produced by the ethanol burner, can provide the necessary heat flux required for maintaining the reforming process. It has been found out that the mass fractions of the hydrogen and carbon dioxide mass fraction are increased along the reformer axis. The hydrogen mass fraction increases with enhancing the radiation heat flux. It was shown that Von Mises stresses increases with heat fluxes. Safety issues concerning the structural integrity of the steel jacket are also addressed. This work clearly shows that by using ethanol which has low temperature conversion, the decrease in structural strength of the steel tube is low. The numerical results clearly indicate that under normal conditions of the ethanol reforming (The temperature of the steel is about 600 °C or 1112 °F), the rupture time of the HK-40 steel alloy increases considerably. For this case the rupture time is greater than 100,000 h (more than 11.4 years). Full article
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Open AccessArticle TiO2 Assisted Photodegradation for Low Substrate Concentrations and Transition Metal Electron Scavengers
ChemEngineering 2018, 2(3), 33; https://doi.org/10.3390/chemengineering2030033
Received: 6 June 2018 / Revised: 13 July 2018 / Accepted: 17 July 2018 / Published: 21 July 2018
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Abstract
Some contaminants of emerging concern (CECs) are known to survive conventional wastewater treatment, which introduces them back to the environment, allowing them to potentially cycle into drinking water. This is especially concerning because of the inherent ability of some CECs to induce physiological
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Some contaminants of emerging concern (CECs) are known to survive conventional wastewater treatment, which introduces them back to the environment, allowing them to potentially cycle into drinking water. This is especially concerning because of the inherent ability of some CECs to induce physiological effects in humans at very low doses. Advanced oxidation processes (AOPs) such as TiO2-based photocatalysis are of great interest for addressing CECs in aqueous environments. Natural water resources often contain dissolved metal cation concentrations in excess of targeted CEC concentrations. These cations may significantly adversely impact the degradation of CECs by scavenging TiO2 surface generated electrons. Consequently, simple pseudo-first-order or Langmuir-Hinshelwood kinetics are not sufficient for reactor design and process analysis in some scenarios. Rhodamine Basic Violet 10 (Rhodamine B) dye and dissolved [Cu2+] cations were studied as reaction surrogates to demonstrate that TiO2-catalyzed degradation for very dilute solutions is almost entirely due to the homogeneous reaction with hydroxyl radicals, and that in this scenario, the hole trapping pathway has a negligible impact. Chemical reaction kinetic studies were then carried out to develop a robust model for RB-[Cu2+] reactions that is exact in the electron pathways for hydroxyl radical production and electron scavenging. Full article
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Open AccessArticle Experimental and CFD Studies of the Hydrodynamics in Wet Agglomeration Process
ChemEngineering 2018, 2(3), 32; https://doi.org/10.3390/chemengineering2030032
Received: 28 May 2018 / Revised: 2 July 2018 / Accepted: 10 July 2018 / Published: 19 July 2018
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Abstract
In this study, an experimentally validated computational model was developed to investigate the hydrodynamics in a rotor-stator vortex agglomeration reactor RVR having a rotating disc at the centre with two shrouded outer plates. A numerical simulation was performed using a simplified form of
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In this study, an experimentally validated computational model was developed to investigate the hydrodynamics in a rotor-stator vortex agglomeration reactor RVR having a rotating disc at the centre with two shrouded outer plates. A numerical simulation was performed using a simplified form of the reactor geometry to compute the 3-D flow field in batch mode operations. Thereafter, the model was validated using data from a 2-D Particle Image Velocimetry (PIV) flow analysis performed during the design of the reactor. Using different operating speeds, namely 70, 90, 110, and 130 rpm, the flow fields were computed numerically, followed by a comprehensive data analysis. The simulation results showed separated boundary layers on the rotating disc and the stator. The flow field within the reactor was characterized by a rotational plane circular forced vortex flow, in which the streamlines are concentric circles with a rotational vortex. Overall, the results of the numerical simulation demonstrated a fairly good agreement between the Computational Fluid Dynamics (CFD) model and the experimental data, as well as the available theoretical predictions. The swirl ratio β was found to be approximately 0.4044, 0.4038, 0.4044, and 0.4043 for the operating speeds of N = 70, 90, 110, and 130 rpm, respectively. In terms of the spatial distribution, the turbulence intensity and kinetic energy were concentrated on the outer region of the reactor, while the circumferential velocity showed a decreasing intensity towards the shroud. However, a comparison of the CFD and experimental predictions of the tangential velocity and the vorticity amplitude profiles showed that these parameters were under-predicted by the experimental analysis, which could be attributed to some of the experimental limitations rather than the robustness of the CFD model or numerical code. Full article
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Open AccessArticle Controlling the Synthesis Conditions for Tuning the Properties of Hydrotalcite-Like Materials at the Nano Scale
ChemEngineering 2018, 2(3), 31; https://doi.org/10.3390/chemengineering2030031
Received: 27 June 2018 / Revised: 7 July 2018 / Accepted: 10 July 2018 / Published: 13 July 2018
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Abstract
Three series of layered double hydroxides (LDH) with a hydrotalcite-like structure and composition corresponding to [Mg4Al2(OH)12(CO3)]·3H2O have been prepared from a common batch by applying three different aging procedures, namely, stirring at room
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Three series of layered double hydroxides (LDH) with a hydrotalcite-like structure and composition corresponding to [Mg4Al2(OH)12(CO3)]·3H2O have been prepared from a common batch by applying three different aging procedures, namely, stirring at room temperature, hydrothermal treatment, and microwave-hydrothermal treatment. It has been found that the tested properties of the samples (mainly related to their crystallinity) are considerably improved by using the microwave-hydrothermal treatment. Shorter times are also evinced than in the other two aging treatments; however, if the microwave-hydrothermal treatment is too far extended, incipient destruction of the particles is observed. Full article
(This article belongs to the Special Issue Advanced Applications of Layered Double Hydroxides)
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Open AccessArticle The Effect of Off-Spec Canola Biodiesel Blending on Fuel Properties for Cold Weather Applications
ChemEngineering 2018, 2(3), 30; https://doi.org/10.3390/chemengineering2030030
Received: 12 February 2018 / Revised: 2 June 2018 / Accepted: 29 June 2018 / Published: 2 July 2018
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Abstract
Biodiesel is a renewable and reduced-emission alternative fuel produced mainly from the alcoholysis of vegetable oils and/or animal fats. It is mainly used in blends with diesel fuel to reduce emissions, enhance lubrication and lower sulfur content. Being able to accurately determine the
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Biodiesel is a renewable and reduced-emission alternative fuel produced mainly from the alcoholysis of vegetable oils and/or animal fats. It is mainly used in blends with diesel fuel to reduce emissions, enhance lubrication and lower sulfur content. Being able to accurately determine the physicochemical properties of blended fuel is important for optimal injection, combustion, and lubricating performance in diesel engines. Also, fuel properties vary as the ratio of biodiesel-diesel changes, affecting the final fuel quality. In this study, a wide range and narrow intervals of (0, 2, 4, 6, 8, 10, 12, 15, 18, 20, 25, 35, 50, 75 and 100% by volume) off-quality canola-based biodiesel blends were prepared at ambient conditions and used to study the blended fuel properties (density, kinematic viscosity, flash point, cloud point and pour point). This is particularly important for examining the effect of a biodiesel content of more than 20%—the industry maximum blend content—on cold flow properties, fuel stability, energy value, and emissions. It was found that the kinematic viscosity and density increased linearly as the concentration of the biodiesel in the blend increases. The pour point and cloud point temperature showed a small increase up to 35% blending ratio and a rapid increase in temperature for biodiesel concentrations higher than 35%. Also, the flash point remained almost constant at an average value of 73 °C for blends less than 20%, above which the values for the flash point increased exponentially with biodiesel concentration. Furthermore, predictive correlations were developed for all tested fuel properties from regressing corresponding experimental data. All models exhibited excellent agreement with experimental data with an average absolute deviation of less than 5%. Full article
(This article belongs to the Special Issue Control and Optimization of Chemical and Biochemical Processes)
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Open AccessArticle Natural Hematite and Siderite as Heterogeneous Catalysts for an Effective Degradation of 4-Chlorophenol via Photo-Fenton Process
ChemEngineering 2018, 2(3), 29; https://doi.org/10.3390/chemengineering2030029
Received: 18 May 2018 / Revised: 9 June 2018 / Accepted: 9 June 2018 / Published: 21 June 2018
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Abstract
This paper describes a simple and low-cost process for the degradation of 4-Chlorophenol (4-CP) from aqueous solution, using natural Tunisian Hematite (M1) and Siderite (M2). Two natural samples were collected in the outcroppings of the Djerissa mining site (Kef
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This paper describes a simple and low-cost process for the degradation of 4-Chlorophenol (4-CP) from aqueous solution, using natural Tunisian Hematite (M1) and Siderite (M2). Two natural samples were collected in the outcroppings of the Djerissa mining site (Kef district, northwestern Tunisia). Both Hematite and Siderite ferrous samples were characterized using several techniques, including X-Ray Diffraction (XRD), Nitrogen Physisorption (BET), Infrared Spectroscopy (FTIR), H2-Temperature Programmed Reduction (H2-TPR), Scanning Electronic Microscopy (SEM) linked with Energy Dispersive X-ray (EDS) and High-Resolution Transmission Electron Microscopy (HRTEM). Textural, structural and chemical characterization confirmed the presence of Hematite and Siderite phases with a high amount of iron on the both surface materials. Their activity was evaluated in the oxidation of 4-CP in aqueous medium under heterogeneous photo-Fenton process. Siderite exhibited higher photocatalytic oxidation activity than Hematite at pH 3. The experimental results also showed that 100% conversion of 4-CP and 54% TOC removal can be achieved using Siderite as catalyst. Negligible metal leaching and catalyst reutilization without any loss of activity point towards an excellent catalytic stability for both natural catalysts. Full article
(This article belongs to the Special Issue Heterogeneous Photocatalysis and Photocatalytic Nanomaterials)
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