ChemEngineering

15 pages, 3810 KiB

Open AccessArticle

Numerical Analysis of Gas Hold-Up of Two-Phase Ebullated Bed Reactor

by Riyadh S. Almukhtar, Ali Amer Yahya, Omar S. Mahdy, Hasan Shakir Majdi, Gaidaa S. Mahdi, Asawer A. Alwasiti, Zainab Y. Shnain, Majid Mohammadi, Adnan A. AbdulRazak, Peter Philib, Jamal M. Ali, Haydar A. S. Aljaafari and Sajda S. Alsaedi

ChemEngineering 2023, 7(5), 101; https://doi.org/10.3390/chemengineering7050101 - 20 Oct 2023

Viewed by 1530

Abstract

Due to the significant increase in heavy feedstocks being transported to refineries and the hydrocracking process, the significance of adopting an ebullated bed reactor has been reemphasized in recent years. The predictive modelling of gas hold-up in an ebullated two-phase reactor was performed [...] Read more.

Due to the significant increase in heavy feedstocks being transported to refineries and the hydrocracking process, the significance of adopting an ebullated bed reactor has been reemphasized in recent years. The predictive modelling of gas hold-up in an ebullated two-phase reactor was performed using 10 machine learning methods based on support vector machine (SVM) and Gaussian process regression (GPR) in this study. In an ebullated bed reactor, the impacts of three features, namely liquid velocity, gas velocity, and recycling ratio, on the gas hold-up were examined. The liquid velocity has the most impact on the predicted gas hold-up, according to the feature significance analysis. The rotational-quadratic, squared-exponential, Matern 5/2, and exponential kernel functions integrated with the GPR models and the linear, quadratic, cubic, fine, medium, and coarse kernel functions integrated with the SVM model performed well during training and testing, with the exception of the fine SVM model, whose R² is very low. According to the R² > 0.9 and low RMSE and MAE values, the rotational-quadratic, squared-exponential, and Matern 5/2 GPR models performed the best. Full article

► Show Figures

Figure 1

31 pages, 6131 KiB

Open AccessArticle

Adaptive Mesh Refinement Strategies for Cost-Effective Eddy-Resolving Transient Simulations of Spray Dryers

by Jairo Andrés Gutiérrez Suárez, Carlos Humberto Galeano Urueña and Alexánder Gómez Mejía

ChemEngineering 2023, 7(5), 100; https://doi.org/10.3390/chemengineering7050100 - 18 Oct 2023

Viewed by 1547

Abstract

The use of adaptive meshing strategies to perform cost-effective transient simulations of spray drying processes is evaluated. These simulations are often computationally expensive, given the large differences between the characteristic times of the central jet and those of the unsteady flow developed at [...] Read more.

The use of adaptive meshing strategies to perform cost-effective transient simulations of spray drying processes is evaluated. These simulations are often computationally expensive, given the large differences between the characteristic times of the central jet and those of the unsteady flow developed at its periphery. Managing the computational cost through the control of the grid resolution by regions is inadequate in many of these applications since the grid resolution requirements change dynamically within the domain. These conditions are related to the unsteady nature of the flow in both the central jet and the flow recirculation zones. Therefore, the application of adaptive mesh refinement (AMR) strategies is recommended. In this paper, general AMR criteria based on relative errors are evaluated by testing three mesh adaptation criteria: velocity gradient, pressure gradient, and vorticity. This evaluation is performed using a low-cost turbulence model with eddy resolution (DDES) in two different types of drying chambers, in which experimental measurements are available. The use of AMR exerts appreciable effects on decreasing computational costs and contributes to the capture of large eddies in critical regions. The present approach provides an appropriate balance between solution accuracy and computational cost. By using a correct AMR configuration, it is possible to obtain results similar to those obtained on a fixed grid but reducing the computational costs by 3 to 5 times. Full article

(This article belongs to the Special Issue Feature Papers in Chemical Engineering)

► Show Figures

Graphical abstract

17 pages, 3809 KiB

Open AccessArticle

Antisolvent Effects of C₁–C₄ Primary Alcohols on Solid-Liquid Equilibria of Potassium Dihydrogen Phosphate in Aqueous Solutions

by Tam Minh Le, Tan Dzung Nguyen, Giang Tien Nguyen and Nhung Thi Tran

ChemEngineering 2023, 7(5), 99; https://doi.org/10.3390/chemengineering7050099 - 17 Oct 2023

Viewed by 1420

Abstract

The focus of this study was to examine antisolvent effects, which hold significance in particulate processes, such as crystallization and precipitation. In the first section, an experimental investigation revealed that C₁–C₄ primary alcohols significantly reduced the solubility of potassium dihydrogen [...] Read more.

The focus of this study was to examine antisolvent effects, which hold significance in particulate processes, such as crystallization and precipitation. In the first section, an experimental investigation revealed that C₁–C₄ primary alcohols significantly reduced the solubility of potassium dihydrogen phosphate (KDP) in water. The solid–liquid equilibria of KDP solutions were determined using an innovative polythermal method, demonstrating time and labor efficiency compared to the traditional isothermal method while maintaining solubility determination quality. This achievement established an efficient tool for high-throughput solvent screening, a crucial aspect of particulate process development. In addition to the experimental approach, in the second part, the influence of these alcohols on KDP solubility was analyzed using the eNRTL thermodynamics model. The model’s estimated parameters confirmed that the addition of these alcohols induced strong non-ideal behavior in the solutions, altered interactions between solute species and solvent components, and reduced KDP solubility. Under the effects of these alcohols, KDP solubility generally increased with the length of the alkyl chain in the added alcohols, although methanol deviated from this observation. Furthermore, the present work also discussed the limitation of the well-known Bromley’s equation, particularly when applied for KDP in alcohol–water mixed solvents. Consequently, binary and ternary systems consisting of KDP, water, and C₁–C₄ primary alcohols were successfully modeled using eNRTL. Furthermore, it was determined that the obtained model was insufficient for quaternary systems with a higher alcohol content, particularly when high-order interactions were neglected as in the cases of binary and ternary systems. In short, these investigated alcohols have potential for future applications in the design of particulate processes, with a particular emphasis on antisolvent crystallization. Full article

► Show Figures

Figure 1

12 pages, 1757 KiB

Open AccessArticle

Fabrication and Characterization of Poly(lactic acid)-Based Biopolymer for Surgical Sutures

by Zaid Abdulhamid Alhulaybi

ChemEngineering 2023, 7(5), 98; https://doi.org/10.3390/chemengineering7050098 - 13 Oct 2023

Cited by 1 | Viewed by 2067

Abstract

Medical sutures are important surgical aids for promoting wound closure and establishing the ideal environment for wound healing. Several key factors must be considered in medical sutures, including the material of choice for the wound closure, the type of injury (internal or external), [...] Read more.

Medical sutures are important surgical aids for promoting wound closure and establishing the ideal environment for wound healing. Several key factors must be considered in medical sutures, including the material of choice for the wound closure, the type of injury (internal or external), the mechanical support required to sustain the closure, the causes of infection, and the suture’s thickness and absorbability. Therefore, this study focuses on producing absorbable surgical sutures from a bio-compatible polymer material called polylactic acid (PLA) along with a PLA–chitosan composite suture initially using the extrusion method followed by the stretching method. The experimental results showed that the PLA suture can be successfully produced and coated with chitosan. The resulting suture elongated up to 148% with an achieved crystallinity of 27%, along with a superior surgical tying and knotting quality. The average thickness of the PLA sutures and PLA sutures coated with chitosan were found to be 0.33 mm and 0.58 mm, respectively. The efficient biocompatibility and wound healing/closure of the sutures were practically deep-rooted using a human skin simulator and rat animal tissue. Based on the degradation study, the manufactured suture in this study proved its degradability in physiological saline water. After a period of 15 days, the sutures lost 50% of their weight and the pH decreased from 6.49 to 4.42. Full article

► Show Figures

Figure 1

15 pages, 757 KiB

Open AccessReview

Energy-Intensive Materials with Mechanically Activated Components

by Bakkara Ayagoz, Sadykov Bakhtiyar, Artykbaeva Aida, Kamunur Kaster, Batkal Aisulu and Kalmuratova Bakhyt

ChemEngineering 2023, 7(5), 97; https://doi.org/10.3390/chemengineering7050097 - 12 Oct 2023

Viewed by 1502

Abstract

The production and study of highly dispersed aluminum-based powders represents one of contemporary science’s priority fields. This is primarily driven by the practical necessity to develop new materials, a feat that, in some cases, can only be achieved through the utilization of powdered [...] Read more.

The production and study of highly dispersed aluminum-based powders represents one of contemporary science’s priority fields. This is primarily driven by the practical necessity to develop new materials, a feat that, in some cases, can only be achieved through the utilization of powdered components. This article presents the results of the mechanochemical treatment method employed to obtain highly reactive aluminum particles. It also includes a comparative analysis of aluminum particles generated through various methods and their respective properties. Furthermore, the application of these highly reactive aluminum particles in energy-intensive materials is discussed. Full article

► Show Figures

Figure 1

27 pages, 4580 KiB

Open AccessArticle

Role of Stearic Acid as the Crystal Habit Modifier in Candelilla Wax-Groundnut Oil Oleogels

by Diksha Chaturvedi, Deepti Bharti, Somali Dhal, Deblu Sahu, Haladhar Behera, Minaketan Sahoo, Doman Kim, Maciej Jarzębski, Arfat Anis, Biswaranjan Mohanty, Sai S. Sagiri and Kunal Pal

ChemEngineering 2023, 7(5), 96; https://doi.org/10.3390/chemengineering7050096 - 12 Oct 2023

Cited by 3 | Viewed by 1766

Abstract

This study investigated the effects of incorporating stearic acid (SAC) in candelilla wax (CW) and groundnut oil (GO) oleogel with potential health benefits as an alternative to saturated fats in processed foods. Results showed that SAC possesses crystal habit-modifying properties on the oleogels, [...] Read more.

This study investigated the effects of incorporating stearic acid (SAC) in candelilla wax (CW) and groundnut oil (GO) oleogel with potential health benefits as an alternative to saturated fats in processed foods. Results showed that SAC possesses crystal habit-modifying properties on the oleogels, causing its average crystallite size to increase, as observed through polarized light microscopy and XRD analysis. Additionally, SAC caused an increase in ordering within the crystallite network as a result of the decrease in d-spacing. Interestingly, the firmness of the oleogels remained unaffected, even at a higher fraction of SAC. It is believed to be due to the interference caused by the crystallization of high-melting SAC within the fine crystal network of CW-GO oleogel. However, adding 3 mg of SAC significantly increased the work of the shear of the oleogel (SAC3), which decreased the spreadability. As observed through colorimetric analysis, SAC3 showed a dense and uniform distribution of prominent bright crystals with minimal amorphous regions, leading to a high whiteness index. SAC3 also demonstrated the highest compactness and dislocation density among the oleogels, likely due to the formation of prominent crystals. However, SAC did not affect the overall oleogel crystallization rate. SAC3 had delayed secondary crystallization and thermal equilibrium by having a prolonged crystallization time of CW crystals. In the case of controlled delivery studies, the addition of SAC improved CPCR. On the other hand, CPCR decreased with the increase in SAC amount, where SAC3 showed a moderate curcumin release ability among the oleogels. Full article

► Show Figures

Figure 1

13 pages, 4842 KiB

Open AccessArticle

Synthesis and Research of Critical Parameters of Bi-HTSC Ceramics Based on Glass Phase Obtained by IR Heating

by Daniyar Uskenbaev, Adolf Nogai, Alisher Uskenbayev, Kairatbek Zhetpisbayev, Eleonora Nogai, Pavel Dunayev, Ainur Zhetpisbayeva and Artur Nogai

ChemEngineering 2023, 7(5), 95; https://doi.org/10.3390/chemengineering7050095 - 10 Oct 2023

Viewed by 1190

Abstract

In this paper influence of the excess Ca and Cu cations on the critical temperature (Tc) and critical transport current density (J_c) of high-temperature superconducting ceramics of the compositions (HTSC) Bi₁_.₆Pb₀_.₄Sr₂Ca [...] Read more.

In this paper influence of the excess Ca and Cu cations on the critical temperature (Tc) and critical transport current density (J_c) of high-temperature superconducting ceramics of the compositions (HTSC) Bi₁_.₆Pb₀_.₄Sr₂Ca₂_.₁Cu₃_.₁O_y, Bi₁_.₆Pb₀_.₄Sr₂Ca₂_.₂₅Cu₃_.₂₅O_y and Bi₁_.₆Pb₀_.₄Sr₂Ca₃Cu₄O_y synthesized by the glass-ceramic method has been studied. The synthesis of superconducting ceramics was carried out on the basis of the glass phase, obtained by ultra-fast quenching of the melt. Melting of the mixture of starting components was carried out without the use of a crucible under the influence of IR radiant heating. Analysis of the elemental composition of the samples of the initial precursors showed a significant deviation from stoichiometry in oxygen (increase), as well as a decrease in calcium content. The synthesis of HTSC ceramics was carried out at a temperature of 849–850 °C for 96 h with intermediate grinding every 24 h. Studies of the phase composition of ceramic samples by X-ray diffraction have shown that HTSC ceramics consist only of a superconducting high-temperature phase Bi-2223. Studies of current-carrying characteristics by the four-point probe method according to the criterion of 1 µV/cm² have shown that high-temperature superconducting ceramics of the compositions Bi₁_.₆Pb₀_.₄Sr₂Ca₂_.₁Cu₃_.₁O_y, Bi₁_.₆Pb₀_.₄Sr₂Ca₂_.₂₅Cu₃_.₂₅O_y and Bi₁_.₆Pb₀_.₄Sr₂Ca₃Cu₄O_y have an increased density of critical transport current of 9.12 A/cm², 7.62 A/cm² and 7.26 A/cm², respectively. At the same time, it was found that with a decrease in the content of Ca and Cu cations in HTSC ceramics, an increase in the critical current density is observed. Full article

► Show Figures

Figure 1

18 pages, 1566 KiB

Open AccessArticle

Chemical Composition of Different Extracts from Echinacea purpurea (L.) Moench Roots and Evaluation of Their Antimicrobial Activity

by Nadezhda Petkova, Ani Petrova, Ivan Ivanov, Ivanka Hambarlyiska, Yulian Tumbarski, Ivayla Dincheva, Manol Ognyanov and Petko Denev

ChemEngineering 2023, 7(5), 94; https://doi.org/10.3390/chemengineering7050094 - 09 Oct 2023

Viewed by 1825

Abstract

This research aimed to reveal the chemical composition of different fractions obtained by sequential extraction of purple coneflower (Echinacea purpurea) roots and to evaluate the antimicrobial activity of some of them. Hexane, chloroform, ethyl acetate, and water were used as solvents [...] Read more.

This research aimed to reveal the chemical composition of different fractions obtained by sequential extraction of purple coneflower (Echinacea purpurea) roots and to evaluate the antimicrobial activity of some of them. Hexane, chloroform, ethyl acetate, and water were used as solvents to obtain the corresponding extracts. A GC-MS analysis was employed to reveal the chemical composition of hexane, chloroform, and ethyl acetate fractions. Conventional and ultrasound-assisted water extraction was performed to isolate inulin-type polysaccharides. Eighteen microorganisms were used for testing the antimicrobial activity of the obtained organic extracts. From GC-MS analysis more than forty compounds were detected in the fractions, including fatty acids, organic acids, fatty alcohols, sterols, and terpenes. Only in ethyl acetate extract were found mannitol and fructose isomers, while in chloroform extract were detected α- and β-amyrin, and betulin. Ethyl acetate fraction demonstrated the highest antimicrobial activity against 11 microorganisms (Bacillus cereus, B. amyloliquefaciens, Staphylococcus aureus, Listeria monocytogenes, Salmonella enteritis, Escherichia coli, Enterococcus faecalis, Pseudomonas aeruginosa, Candida albicans, Saccharomices cerevisiae, and Peniclium sp.). The polysaccharide fractions were structurally characterized by FT-IR and NMR studies as linear inulin having β-(2→1)-linked Fru units and a T-Glc unit linked α-(1→2). Inulin from coneflower roots showed poor flowability, promising bulk and tapped density, swelling properties, and better oil-holding than water-holding capacity. This study demonstrated the potential of coneflower root fractions as a rich source of phytochemicals with antimicrobial activities and potential prebiotic activity due to inulin content (15% yield) and echinacea root as a useful biobased industrial crop/material. Full article

► Show Figures

Figure 1

21 pages, 4535 KiB

Open AccessArticle

Natural Gas Liquids into Motor Gasolines: Methodology for Processing on a Zeolite Catalyst and Development of Blending Recipes

by Andrey Altynov, Ilya Bogdanov, Daniil Lukyanov and Maria Kirgina

ChemEngineering 2023, 7(5), 93; https://doi.org/10.3390/chemengineering7050093 - 07 Oct 2023

Cited by 1 | Viewed by 1432

Abstract

Natural gas liquids are a by-product of natural gas preparation, one of the most common and environmentally friendly energy sources. In natural gas fields located in remote areas, there is no resource-efficient way to use natural gas liquids. However, natural gas liquids are [...] Read more.

Natural gas liquids are a by-product of natural gas preparation, one of the most common and environmentally friendly energy sources. In natural gas fields located in remote areas, there is no resource-efficient way to use natural gas liquids. However, natural gas liquids are a valuable hydrocarbon feedstock for the production of motor fuels, in particular motor gasolines. The aim of this work is to develop a method for obtaining motor gasolines by processing natural gas liquids on a zeolite catalyst, taking into account the influence of the particle size of the zeolite catalyst, the technological parameters of the process, and the composition of the feedstock. As part of the work, for the first time, regularities of the influence of zeolite catalyst particle size, technological parameters of the process and the composition of feedstock on the composition and characteristics of the resulting processed products were revealed. A database about the composition and characteristics of natural gas liquids, obtained from various gas fields in Western Siberia of the Russian Federation, has been accumulated. During the study, it was found that the optimal particle size of the zeolite catalyst is 0.50–1.00 mm; optimal technological parameters are a temperature of 375 °C, pressure 2.5 atm. and the feedstock space velocity 2 h⁻¹. It is shown that the processing of natural gas liquids of various compositions on a zeolite catalyst, on average, makes it possible to increase their detonation resistance by more than 16 points. The results obtained indicate the prospects of using the process for the production of motor gasoline. The paper presents a number of blending recipes for obtaining fuels, both within the framework of production at the fields and at processing plants. Full article

► Show Figures

Figure 1

20 pages, 3808 KiB

Open AccessArticle

Investigating the Effect of Thermal Annealing and Changing the Concentration of GO in GO/PVA Nanocomposites on Their Structural, Electrical, and Optical Properties

by Lala Gahramanli, Mustafa Muradov, Goncha Eyvazova, Mahammad Baghir Baghirov, Sevinj Mammadyarova, Gunel Aliyeva, Elman Hajiyev, Faig Mammadov and Stefano Bellucci

ChemEngineering 2023, 7(5), 92; https://doi.org/10.3390/chemengineering7050092 - 04 Oct 2023

Cited by 1 | Viewed by 1602

Abstract

The present research involves producing graphene oxide (GO) using the Hummers method, generating a composite using GO and PVA, and analyzing these composites’ structural and optical characteristics. PVA and GO were used in varied percentages to deal with the issue of how the [...] Read more.

The present research involves producing graphene oxide (GO) using the Hummers method, generating a composite using GO and PVA, and analyzing these composites’ structural and optical characteristics. PVA and GO were used in varied percentages to deal with the issue of how the features of GO/PVA alter depending on concentration. The impact of thermal annealing on the structure and optical characteristics of GO/PVA materials at various concentrations were also investigated. UV-VIS was used to investigate the band gap value of GO/PVA composites. The band gap value changed due to an increase in the concentration of GO in the composites in the PVA and the impact of thermal annealing. The band gap value, specific resistance, and dielectric constant were all found to be well controlled by varying the thermal annealing temperature and the concentration of GO in this case. Differential Scanning Calorimetry (DSC) and thermogravimetric analysis (TGA) were performed on pure PVA and GO/PVA samples in various percentages of GO in order to examine the effect of temperature on the physical properties of (n = 1, 2, 3, 5, 20%) nGO%/PVA nanocomposites. Thermal stability increased as the fraction of GO in the PVA polymer matrix increased. Full article

► Show Figures

Figure 1

15 pages, 13098 KiB

Open AccessArticle

Electrokinetic Forces as an Electrical Measure of Chemical Aging Potential in Granular Materials

by Miguel Castilla-Barbosa, Orlando Rincón-Arango and Manuel Ocampo-Terreros

ChemEngineering 2023, 7(5), 91; https://doi.org/10.3390/chemengineering7050091 - 01 Oct 2023

Viewed by 1651

Abstract

The zeta potential of soils is an electric potential in the double-layer interface and is a physical property exhibited by any particle related to electrochemical attractive forces. On the other hand, the chemical aging phenomenon is seen as the chief mechanism of the [...] Read more.

The zeta potential of soils is an electric potential in the double-layer interface and is a physical property exhibited by any particle related to electrochemical attractive forces. On the other hand, the chemical aging phenomenon is seen as the chief mechanism of the aging of sands due to the dissolution and precipitation of minerals, resulting in the development of the cementation of particles in granular mediums. The present investigation focuses on determining whether granular materials can generate cementation due to electrokinetic forces, and if the zeta potential could be related as a measure of the potential of chemical aging. X-ray fluorescence and diffraction tests were performed to characterize four representative fractions of one kind of sand, and zeta potential studies were carried out to determine the electrical potential on the mineral surfaces of each one. Zeta potential analysis showed both dependence on the mineralogical content and the variation in the pH of the colloidal solution fluid because the increase in OH- ion concentrations increases the thickness of the diffuse double layer and the electrokinetic forces of attraction. Moreover, the zeta potential showed an increase in the thickness of the diffuse double layer, due to the electrokinetic forces, which can be associated with the development of cohesive forces with a dependence on the mineralogy of sands. Full article

► Show Figures

Figure 1

18 pages, 4568 KiB

Open AccessArticle

A Phytochemical Approach to the Removal of Contaminants from Industrial Dyeing Wastewater

by Néstor A. Urbina-Suarez, Cristian J. Salcedo-Pabón, Jefferson E. Contreras-Ropero, German L. López-Barrera, Janet B. García-Martínez, Andrés F. Barajas-Solano and Fiderman Machuca-Martínez

ChemEngineering 2023, 7(5), 90; https://doi.org/10.3390/chemengineering7050090 - 28 Sep 2023

Cited by 1 | Viewed by 1265

Abstract

This study investigates the influence of photoperiod and wastewater concentration on the growth of microalgae and cyanobacteria for the removal of environmentally significant parameters (COD, BOD, Cr, Fe, color, chlorides, nitrogen compounds, and phosphates) from dyeing wastewater. A two-factor central composite design with [...] Read more.

This study investigates the influence of photoperiod and wastewater concentration on the growth of microalgae and cyanobacteria for the removal of environmentally significant parameters (COD, BOD, Cr, Fe, color, chlorides, nitrogen compounds, and phosphates) from dyeing wastewater. A two-factor central composite design with surface response was employed, involving two algae species (Chlorella and Scenedesmus sp.) and two cyanobacteria species (Hapalosiphon and Oscillatoria sp.). The findings indicated that extended photoperiods (>13 h) and higher wastewater concentrations (70–80% v/v) enhanced biomass production across all strains. However, Hapalosiphon and Chlorella sp. (1.6 and 0.45 g/L) exhibited better tolerance to the wastewater’s high toxicity, resulting in higher biomass concentrations and improved COD and BOD removal by Hapalosiphon sp. (75% and 80%, respectively). Further analysis of the obtained biomass revealed their potential applications. Among the cyanobacteria, Hapalosiphon sp. synthesized the highest concentrations of total proteins and lipids (38% and 28% w/w, respectively), while Oscillatoria sp. displayed a high protein content (42% w/w). In contrast, the algae demonstrated a strong propensity for storing substantial quantities of total carbohydrates (65% and 57% w/w for Scenedesmus and Chlorella sp., respectively). These results signify the feasibility of cultivating photosynthetic microorganisms in industrial dyeing wastewater as a sustainable source of nutrients for targeted metabolite production. Full article

► Show Figures

Figure 1

15 pages, 1117 KiB

Open AccessArticle

Modeling and Adoption of Technological Solutions in Order to Enhance the Effectiveness of Measures to Limit Water Inflows into Oil Wells under Conditions of Uncertainty

by G. Zh. Moldabayeva, G. M. Efendiyev, A. L. Kozlovskiy, N. S. Buktukov and S. V. Abbasova

ChemEngineering 2023, 7(5), 89; https://doi.org/10.3390/chemengineering7050089 - 19 Sep 2023

Cited by 2 | Viewed by 1199

Abstract

This article is devoted to the construction and statistical analysis of models that express the relationship between performance indicators and a large number of geological and technological factors. The volume of additionally produced oil, the volume of limited water, the duration of the [...] Read more.

This article is devoted to the construction and statistical analysis of models that express the relationship between performance indicators and a large number of geological and technological factors. The volume of additionally produced oil, the volume of limited water, the duration of the effect and profit per well, taking into account the cost of the polymer, are taken as performance indicators. The key goal of the article is to develop a method and models for making technological choices to enhance the effectiveness of measures to limit water inflows in production wells under conditions of uncertainty. The methodological basis of the study was the provisions and principles of mathematical statistics, the theory of fuzzy sets, the theory of decision-making under conditions of uncertainty based on materials generated by statistical processing of data on physical and geological conditions, and the results of waterproofing work, obtaining, and analyzing information. The scientific novelty of the study lies in the construction of technological solutions based on modeling the performance indicators of waterproofing works with an assessment of the significance of each factor and the reliability of the models and decision-making under conditions of uncertainty, expressed by multi-criteria and multi-factoriality. The practical significance follows from a solution that satisfies the conditions for achieving the maximum of all indicators of the efficiency of the process of limiting water inflows, both technological and economic. An algorithm was developed and implemented for evaluating optimal technological solutions according to four criteria based on information about the geological and physical conditions of the field and the experience of implementing geological and technical measures to limit water inflows, including the analysis of factors, their weighted contribution, model building, statistical evaluation of reliability indicators, decision-making taking into account uncertainty. Full article

► Show Figures

Figure 1

12 pages, 3364 KiB

Open AccessPerspective

Time Crystal Synthon: The Way to Integrate Cascade Reactions for Advancing Multistep Flow Synthesis

by Pathik Sahoo

ChemEngineering 2023, 7(5), 88; https://doi.org/10.3390/chemengineering7050088 - 18 Sep 2023

Cited by 1 | Viewed by 1371

Abstract

Multistep flow catalytic reactions in organic chemistry integrate multiple sequential organic reactions to enhance cost-efficiency, time management, and labour resources, all while boosting effectiveness and environmental sustainability. Similar to how we select molecular synthons for reactions in retrosynthesis, we can employ time-crystal synthons [...] Read more.

Multistep flow catalytic reactions in organic chemistry integrate multiple sequential organic reactions to enhance cost-efficiency, time management, and labour resources, all while boosting effectiveness and environmental sustainability. Similar to how we select molecular synthons for reactions in retrosynthesis, we can employ time-crystal synthons to integrate catalytic reaction cycles in the development of a reaction pathway. This involves considering individual catalytic reaction steps of cycles as time-consuming events that can be topologically arranged like a clock. This results in a perpetual machine that violates time translational symmetry, leading to the production of a time crystal. This approach involves transferring a single product from one catalytic cycle to a neighbouring reaction cycle, connecting various reaction vessels vertically to establish a ‘cascade’ of reaction cycles. Additionally, catalytic cycles can be integrated by sharing common reaction steps or implementing a metathesis reaction at the junction zone of two neighbouring cycles. Here, the concept of time-crystal synthons facilitates the linear integration of heterogeneous catalytic cycles, step by step, to transfer products through the common reaction medium when modifying conventional flow synthesis. Significantly, this time-crystal synthon-driven multistep approach offers advantages over conventional flow synthesis, as the reaction vessels can be equipped with microwave and photosynthesis methodologies, allowing for the collection of specific products from their respective vessels as needed, providing more options to integrate reactions and enabling flow control using gravity. Full article

► Show Figures

Scheme 1

18 pages, 6201 KiB

Open AccessFeature PaperArticle

Numerical Simulation, Preparation, and Evaluation of Cu(In, Ga)Se₂ (CIGS) Thin-Film Solar Cells

by Borhan Albiss and Mohammad Al-Widyan

ChemEngineering 2023, 7(5), 87; https://doi.org/10.3390/chemengineering7050087 - 15 Sep 2023

Cited by 1 | Viewed by 1755

Abstract

This study presents the numerical simulation, optimization, preparation, and characterization of Cu(In, Ga)Se₂ (CIGS) thin-film solar cells (TFSCs). Different cell parameters were investigated, including Ga/(Ga+In) (GGI) ratios, the thicknesses of CIGS absorption layers, the fill factor (FF), the open-circuit voltage (Voc), and [...] Read more.

This study presents the numerical simulation, optimization, preparation, and characterization of Cu(In, Ga)Se₂ (CIGS) thin-film solar cells (TFSCs). Different cell parameters were investigated, including Ga/(Ga+In) (GGI) ratios, the thicknesses of CIGS absorption layers, the fill factor (FF), the open-circuit voltage (Voc), and the short-circuit current (Isc). The effects of the simulated parameters on the power conversion efficiency (η) of each prototype CIGS cells were investigated. The optimal GGI ratio was approximately 0.6. Using COMSOL Multiphysics software, a CIGS layer thickness of 2 μm and an η of 17% was calculated, assuming constant operating temperatures. Moreover, prototype CIGS solar cells with various compositions were prepared via a simple and cost-effective method based on sol–gel, sonication, and spin-coating techniques. The microstructures and electrical and optical properties of the CIGS-based solar cells were evaluated using current–voltage (I-V) characteristics, scanning electron microscopy (SEM), X-ray diffraction, atomic force microscopy (AFM), and UV-vis spectroscopy. The elemental compositions of the solar cell layers were evaluated via energy-dispersive X-ray fluorescence (EDXRF). The obtained results were compared with the experimental results. For example, in a prototype cell with a CIGS absorption layer thickness of 2 μm and a GGI ratio of 0.6, the experimental value of η was about 15%. Our results revealed that the agreement between the simulation results and the experimental findings for most of the simulated parameters is quite good. These findings indicate that a non-destructive analysis based on EDXRF is a versatile tool for evaluating CIGS solar cells in a very short time with excellent repeatability for both layer composition and thickness. Full article

► Show Figures

Figure 1

15 pages, 3563 KiB

Open AccessArticle

Bicarbonate-Activated Hydrogen Peroxide for an Azo Dye Degradation: Experimental Design

by Karla Y. Mora-Bonilla, Iván F. Macías-Quiroga, Nancy R. Sanabria-González and María T. Dávila-Arias

ChemEngineering 2023, 7(5), 86; https://doi.org/10.3390/chemengineering7050086 - 14 Sep 2023

Cited by 2 | Viewed by 1228

Abstract

The present study investigated the degradation of an aqueous Allura Red AC (AR–AC) solution by activating hydrogen peroxide with bicarbonate using cobalt ion (Co²⁺) as the catalyst. Four independent variables (H₂O₂, NaHCO₃, Co²⁺, [...] Read more.

The present study investigated the degradation of an aqueous Allura Red AC (AR–AC) solution by activating hydrogen peroxide with bicarbonate using cobalt ion (Co²⁺) as the catalyst. Four independent variables (H₂O₂, NaHCO₃, Co²⁺, and dye concentrations) were analyzed in the composite central design (CCD). AR–AC degradation was optimized using the response surface methodology (RSM). Under optimal degradation conditions (41.86 mg/L AR–AC, 5.58 mM H₂O₂, 2.00 mM NaHCO₃, and 9.00 µM Co²⁺), decolorization > 99.86%, mineralization (CO₂ to conversion) of 12.99%, and total nitrogen removal of 51.97% were achieved. The predicted values for the three response variables were consistent with the experimental values, with determination coefficients (R²) greater than 0.9053. Because cobalt ions (Co²⁺) are a source of water pollution, after oxidation, these were adsorbed on sodium bentonite (Na–Bent), obtaining a final concentration of <0.01 mg/L. Bicarbonate-activated hydrogen peroxide is a potential technology for dye wastewater treatment that operates at an alkaline pH and at ambient temperature. Full article

(This article belongs to the Topic Advances in Chemistry and Chemical Engineering)

► Show Figures

Figure 1

13 pages, 2888 KiB

Open AccessArticle

Enhancing Heat Transfer Performance in Simulated Fischer–Tropsch Fluidized Bed Reactor through Tubes Ends Modifications

by Laith S. Sabri, Abbas J. Sultan, Jamal M. Ali, Hasan Shakir Majdi and Muthanna H. Al-Dahhan

ChemEngineering 2023, 7(5), 85; https://doi.org/10.3390/chemengineering7050085 - 14 Sep 2023

Cited by 1 | Viewed by 1207

Abstract

Fluidized bed reactors are essential in a wide range of industrial applications, encompassing processes such as Fischer–Tropsch synthesis and catalytic cracking. The optimization of performance and reduction in energy consumption in these reactors necessitate the use of efficient heat transfer mechanisms. The present [...] Read more.

Fluidized bed reactors are essential in a wide range of industrial applications, encompassing processes such as Fischer–Tropsch synthesis and catalytic cracking. The optimization of performance and reduction in energy consumption in these reactors necessitate the use of efficient heat transfer mechanisms. The present work examines the considerable impact of tube end geometries, superficial gas velocity, and radial position on heat transfer coefficients within fluidized bed reactors. It was found that the tapered tube end configurations have been empirically proven to improve energy efficiency in fluidized bed reactors significantly. For example, at a superficial gas velocity of 0.4 m/s, the tapered end form’s local heat transfer coefficient (LHTC) demonstrated a significant 20% enhancement compared to the flat end shape. The results and findings of this work make a valuable contribution to the advancement of complex models, enhance the efficiency of fluidized bed reactor processes, and encourage further investigation into novel tube geometries. Full article

► Show Figures

Figure 1

15 pages, 6844 KiB

Open AccessArticle

Crystallization Behavior of Ceritinib: Characterization and Optimization Strategies

by Iva Zokić and Jasna Prlić Kardum

ChemEngineering 2023, 7(5), 84; https://doi.org/10.3390/chemengineering7050084 - 14 Sep 2023

Cited by 2 | Viewed by 1164

Abstract

Because of the specific thermodynamic properties of active pharmaceutical ingredients, the process of crystallization often meets implementation challenges in the pharmaceutical industry. Therefore, it is essential to select the appropriate method and system for the crystallization of a drug. Ceritinib, an active ingredient [...] Read more.

Because of the specific thermodynamic properties of active pharmaceutical ingredients, the process of crystallization often meets implementation challenges in the pharmaceutical industry. Therefore, it is essential to select the appropriate method and system for the crystallization of a drug. Ceritinib, an active ingredient in the treatment of lung cancer, was formed as a result of pH modification during the cooling crystallization of ceritinib dihydrochloride solution. By carrying out processes in various solvent systems, several polymorphs were produced. A combination of forms B and C was generated in the ethanol–water system, resulting in smaller crystals. The acetone–water system produced pure form A, which has larger crystals and is more applicable for forthcoming studies. To additionally enhance granulometric properties, ceritinib form A was recrystallized in tetrahydrofuran at different temperatures using antisolvent crystallization. Crystallization at a higher saturation temperature results in larger and more compact crystals, which enhances filtration and drying. Full article

► Show Figures

Figure 1

11 pages, 3987 KiB

Open AccessArticle

Assessment of Bioactive Compounds in Red Peppercorns (Piper nigrum L.) for the Development of Red Peppercorns Powder

by Sovannmony Lay, Sochetra Sen and Peany Houng

ChemEngineering 2023, 7(5), 83; https://doi.org/10.3390/chemengineering7050083 - 12 Sep 2023

Viewed by 1889

Abstract

Red pepper powder is used as a spice added to various types of foods to improve the spiciness and aroma of foods. The unique aroma and spiciness of red pepper are related to the contents of bioactive compounds, including alkaloids, phenolic compounds, terpenes, [...] Read more.

Red pepper powder is used as a spice added to various types of foods to improve the spiciness and aroma of foods. The unique aroma and spiciness of red pepper are related to the contents of bioactive compounds, including alkaloids, phenolic compounds, terpenes, and flavonoids. These phytochemical compounds have extensively provided many biological activities, such as antioxidant, anti-inflammatory, and antimicrobial. The assessment of bioactive compounds in red pepper is crucial to evaluate the quality of red pepper powder. Therefore, the objective of this study aimed to analyze total phenolic and total flavonoid compounds for further red peppercorn powder application. To assess the contents of bioactive compounds, Response Surface Methodology (RSM) with Box–Behnken Design (BBD) was applied to design the experiment and analyze the data. Furthermore, extraction conditions such as extraction time (30 to 150 min), temperature (35 to 65 °C), and solid-to-solvent ratio (0.5:10 to 0.5:20 g/mL) were investigated for their effects on the yield of total phenolic and total flavonoid contents. The result of this study found that all extraction parameters significantly affected the extraction yields of phenolic and flavonoid compounds. The aroma and taste of red pepper powder can be adjusted by changing extraction conditions such as temperature, time, and solid-to-solvent ratio because changing these conditions allowed the bioactive compounds to be extracted from red pepper at different concentrations. Overall, the assessment of bioactive compounds in red peppercorns holds significant importance for their application as red peppercorn powder. Full article

► Show Figures

Figure 1

15 pages, 3127 KiB

Open AccessArticle

Chitosan–Resole–Pectin Aerogel in Methylene Blue Removal: Modeling and Optimization Using an Artificial Neuron Network

by Jean Flores-Gómez, Mario Villegas-Ruvalcaba, José Blancas-Flores and Juan Morales-Rivera

ChemEngineering 2023, 7(5), 82; https://doi.org/10.3390/chemengineering7050082 - 11 Sep 2023

Cited by 1 | Viewed by 1202

Abstract

In this study, a novel chitosan–resole–pectin aerogel (CS–R–P) was created from a sol–gel reaction with a solution of Cs and P with resole by a freeze-drying technique, and this adsorbent was proposed for the removal of methylene blue (MB). In addition, with the [...] Read more.

In this study, a novel chitosan–resole–pectin aerogel (CS–R–P) was created from a sol–gel reaction with a solution of Cs and P with resole by a freeze-drying technique, and this adsorbent was proposed for the removal of methylene blue (MB). In addition, with the use of an artificial intelligence technique known as an artificial neural network (ANN), this material was modeled and optimized. Its physical morphology and chemical composition were also characterized with FTIR and XPS, and its adsorption properties were analyzed. For modeling the adsorption process, three main parameters were used: the chitosan–resole–pectin concentration (45–75%), thermal treatment (6–36 h), and known concentrations of methylene blue (25–50 and 100 mg/L), established on the Box–Behnken design. The ANN was coupled with the improved gray wolf optimization (IWGO) metaheuristic algorithm, achieving a correlation coefficient of R² = 0.99. The characterization indicates that the surface of the aerogels was micro- and mesoporous, the resole gave physical stability, and the polysaccharide base delivered the functional groups necessary for dye adsorption; the aerogels were successful dye adsorbents with a q_e of 12.44 mg/g. Finally, the physical and chemical sorption was ascertainable with an adsorption that followed pseudo-second-order kinetics. The MB adsorption was clearly occurring though cation exchange and hydrogen binding as observed in the chemical composition. The ANN with the gray wolf optimizer was used for the prediction of the best operating parameters for MB removal, applying the following conditions—the CS–R–P aerogel concentration (52/30/18), the thermal treatment (9.12 h), and the initial concentration of methylene blue (37 mg/L)—achieving a 94.6% removal. These conclusions suggest that using artificial intelligence such as an ANN can provide an efficient and practical model for maximizing the removal action of new aerogels based on chitosan. Full article

► Show Figures

Figure 1

11 pages, 3562 KiB

Open AccessArticle

Rheology of Aqueous Ferrofluids: Transition from a Gel-Like Character to a Liquid Character in High Magnetic Fields

by Stanislav Čampelj

ChemEngineering 2023, 7(5), 81; https://doi.org/10.3390/chemengineering7050081 - 07 Sep 2023

Viewed by 1067

Abstract

Rheological measurements under an applied magnetic field were used to investigate the changes to the internal structure and stability of an aqueous ferrofluid. The ferrofluid was prepared by dispersing 1.8 wt.% of maghemite nanoparticles with a size of d = 14 ± 3 [...] Read more.

Rheological measurements under an applied magnetic field were used to investigate the changes to the internal structure and stability of an aqueous ferrofluid. The ferrofluid was prepared by dispersing 1.8 wt.% of maghemite nanoparticles with a size of d = 14 ± 3 nm and a saturation magnetization M_S = 68 emu/g in water using citric acid as the surfactant. In this study, oscillatory tests were used to investigate the internal structural changes and the stability of ferrofluid under the influence of the magnetic field B. In a magnetic field of approximately 50 mT, the G′ became higher than the loss modulus G″ as the ferrofluid exhibited a gel-like character. However, at a magnetic field of approximately 200 mT, the character of the ferrofluid reverted to that of a liquid. The change in the character of the ferrofluid in this high magnetic field was associated with a gradual change from chain agglomerates to the energetically more favourable globular agglomerates, using a calculation based on a model described in a separate work. The globular agglomerates impeded the flow to a much lesser degree than the chains, causing a reduction in the viscosity. Further increase of the magnetic field resulted in sedimentation of agglomerates and loss of magneto-rheological effect. Full article

► Show Figures

Figure 1

19 pages, 3048 KiB

Open AccessArticle

Modeling the Mechanical Properties of a Polymer-Based Mixed-Matrix Membrane Using Deep Learning Neural Networks

by Zaid Abdulhamid Alhulaybi, Muhammad Ali Martuza and Sayeed Rushd

ChemEngineering 2023, 7(5), 80; https://doi.org/10.3390/chemengineering7050080 - 04 Sep 2023

Viewed by 1314

Abstract

Polylactic acid (PLA), the second most produced biopolymer, was selected for the fabrication of mixed-matrix membranes (MMMs) via the incorporation of HKUST-1 metal–organic framework (MOF) particles into a PLA matrix with the aim of improving mechanical characteristics. A deep learning neural network (DLNN) [...] Read more.

Polylactic acid (PLA), the second most produced biopolymer, was selected for the fabrication of mixed-matrix membranes (MMMs) via the incorporation of HKUST-1 metal–organic framework (MOF) particles into a PLA matrix with the aim of improving mechanical characteristics. A deep learning neural network (DLNN) model was developed on the TensorFlow 2 backend to predict the mechanical properties, stress, strain, elastic modulus, and toughness of the PLA/HKUST-1 MMMs with different input parameters, such as PLA wt%, HKUST-1 wt%, casting thickness, and immersion time. The model was trained and validated with 1214 interpolated datasets in stratified fivefold cross validation. Dropout and early stopping regularizations were applied to prevent model overfitting in the training phase. The model performed consistently for the unknown interpolated datasets and 26 original experimental datasets, with coefficients of determination (R2) of 0.93–0.97 and 0.78–0.88, respectively. The results suggest that the proposed method can build effective DLNN
models using a small dataset to predict material properties. Full article

► Show Figures

Figure 1

11 pages, 2000 KiB

Open AccessArticle

Interconversion and Removal of Inorganic Nitrogen Compounds via UV Irradiation

by Alejandro M. Senn and Natalia Quici

ChemEngineering 2023, 7(5), 79; https://doi.org/10.3390/chemengineering7050079 - 31 Aug 2023

Viewed by 1023

Abstract

Dissolved inorganic nitrogen (DIN) species are key components of the nitrogen cycle and are the main nitrogen pollutants in groundwater. This study investigated the interconversion and removal of the principal DIN compounds (

{NO}_{3}^{-}

,

{NO}_{2}^{-}

and [...] Read more.

Dissolved inorganic nitrogen (DIN) species are key components of the nitrogen cycle and are the main nitrogen pollutants in groundwater. This study investigated the interconversion and removal of the principal DIN compounds (

{NO}_{3}^{-}

,

{NO}_{2}^{-}

and

{NH}_{4}^{+}

) via UV light irradiation using a medium-pressure mercury lamp. The experiments were carried out systematically at relatively low nitrogen concentrations (1.5 mM) at varying pHs in the presence and absence of oxygen to compare the reaction rates and suggest the reaction mechanisms.

{NO}_{3}^{-}

was fully converted into

{NO}_{2}^{-}

at a pH > 3 in both oxic and anoxic conditions, and the reaction was faster when the pH was increased following a first-order kinetic at pH 11 (k = 0.12 min⁻¹, R² = 0.9995).

{NO}_{2}^{-}

was partially converted into

{NO}_{3}^{-}

only at pH 3 and in the presence of oxygen and was stable at an alkaline pH. This interconversion of

{NO}_{3}^{-}

and

{NO}_{2}^{-}

did not yield nitrogen loss in the solution. The addition of formic acid as an electron donor led to the reduction of

{NO}_{3}^{-}

to

{NH}_{4}^{+}

. Conversely,

{NH}_{4}^{+}

was converted into

{NO}_{2}^{-}

,

{NO}_{3}^{-}

and to an unidentified subproduct in the presence of

O_{2}^{}

at pH 10. Finally, it was demonstrated that

{NO}_{2}^{-}

and

{NH}_{4}^{+}

react via UV irradiation with stoichiometry 1:1 at pH 10 with the total loss of nitrogen in the solution. With these results, a strategy to remove DIN compounds via UV irradiation was proposed with the eventual use of solar light. Full article

(This article belongs to the Special Issue Process Intensification for Chemical Engineering and Processing)

► Show Figures

Figure 1

23 pages, 3762 KiB

Open AccessArticle

Dynamic and Steady-State Simulation Study for the Stabilization of Natural Gas Condensate and CO₂ Removal through Heating and Pressure Reduction

by Mohsin Ehsan, Usman Ali, Farooq Sher, Hafiz M. Abubakar and Muhammad Fazal Ul Basit

ChemEngineering 2023, 7(5), 78; https://doi.org/10.3390/chemengineering7050078 - 29 Aug 2023

Viewed by 1785

Abstract

Stabilization of condensate is a highly energy-consuming process compared to other oil and gas processes. There is a need to reduce this energy consumption. Therefore, the present work aims to simulate the stabilization unit in terms of available energy and on-spec stabilized condensate [...] Read more.

Stabilization of condensate is a highly energy-consuming process compared to other oil and gas processes. There is a need to reduce this energy consumption. Therefore, the present work aims to simulate the stabilization unit in terms of available energy and on-spec stabilized condensate products. Natural gas condensate liquids (NGL) need to be stabilized by eliminating lighter hydrocarbon gases and acid gases before being sent to the refinery. Stabilized NGL has the vapor pressure determined as a Reid vapor pressure of 7 psia, showing that light components did not evolve as a separate gas phase. Stabilization and CO₂ removal was performed through the distillation method by heating and pressure reduction using steady state and dynamic simulation through Aspen HYSYS. Different process alterations around the exchanger and column have been studied based on the utilities available for the stabilization and CO₂ removal process. Sensitivity studies, including the impact of CO₂ concentration, the temperature at the inlet of the stabilizer flash separator, and the dynamic simulation for the PID controller, have been performed to analyze the impact on the process parameters, such as Reid vapor pressure (RVP) and CO₂ of the rundown air cooler and heat duties of the exchangers. Actual plant data have been used for the validation of process simulation values for the accuracy of the condensate stabilization unit model. Based on the scenarios analyzed, it can be concluded that the nitrogen stripping method achieved 7 ppmv CO₂ and 7 psia RVP in the condensate from the cooler outlet, while a variation of 29 bpd was observed for the stabilized condensate flowrate throughout all scenarios with data validation showing 0.24% discrepancy between Aspen Hysys data and actual plant data. Full article

(This article belongs to the Collection Green and Environmentally Sustainable Chemical Processes)

► Show Figures

Figure 1

32 pages, 3030 KiB

Open AccessReview

Modifying Superparamagnetic Iron Oxide Nanoparticles as Methylene Blue Adsorbents: A Review

by Linh Doan

ChemEngineering 2023, 7(5), 77; https://doi.org/10.3390/chemengineering7050077 - 28 Aug 2023

Cited by 6 | Viewed by 1893

Abstract

Methylene blue (MB) is a hazardous chemical that is widely found in wastewater, and its removal is critical. One of the most common methods to remove MB is adsorption. To enhance the adsorption process, magnetic adsorbents, particularly those based on superparamagnetic iron oxide [...] Read more.

Methylene blue (MB) is a hazardous chemical that is widely found in wastewater, and its removal is critical. One of the most common methods to remove MB is adsorption. To enhance the adsorption process, magnetic adsorbents, particularly those based on superparamagnetic iron oxide nanoparticles (SPION), play a vital role. This study focuses on comparing recent novel SPION-based MB adsorbents and how to acquire the critical parameters needed to evaluate the adsorption and desorption mechanisms, including isotherms, kinetics, and thermodynamic properties. Moreover, the review article also discusses the future aspects of these adsorbents. Full article

► Show Figures

Figure 1

12 pages, 1163 KiB

Open AccessArticle

Chemical and Process Inherent Safety Analysis of Large-Scale Suspension Poly(Vinyl Chloride) Production

by Ángel Darío González-Delgado, Eduardo Aguilar-Vásquez and Miguel Ramos-Olmos

ChemEngineering 2023, 7(5), 76; https://doi.org/10.3390/chemengineering7050076 - 24 Aug 2023

Cited by 1 | Viewed by 1543

Abstract

In this work, a safety assessment was carried out for the suspension polymerization method, known for the lack of studies about its sustainable performance and long history of chemical accidents. Therefore, a safety analysis was conducted using the inherent safety methodology to assess [...] Read more.

In this work, a safety assessment was carried out for the suspension polymerization method, known for the lack of studies about its sustainable performance and long history of chemical accidents. Therefore, a safety analysis was conducted using the inherent safety methodology to assess and determine the inherent risks of the poly(vinyl chloride) (PVC) suspension production process using computer-aided process engineering (CAPE). The indicators were calculated using data from safety databases and the specialized literature, considering downstream stages like vinyl chloride monomer (VCM) recovery, PVC purification and PVC drying. The obtained indicators revealed that the process has a negative performance regarding inherent safety, with a total inherent safety index of 30. The chemical inherent safety index had a value of 19, with the main chemical risk of the process being presented by the vinyl chloride monomer (with a value of 11), along with the risk of the exothermic reactions. The process safety index had a value of 15, highlighting the inventory as the primary concern of the process (with a value of 5), followed by the presence of unsafe equipment such as furnaces, burners, and dryers. The safety structure index had a score of 3, categorizing the process as probably risky, with the reaction and purification stages being more susceptible to accidents. Lastly, it is recommended to reduce the size of the process inventory and to substitute out unsafe process units. Full article

► Show Figures

Figure 1

14 pages, 3542 KiB

Open AccessArticle

Effects of Phosphate and Thermal Treatments on the Characteristics of Activated Carbon Manufactured from Durian (Durio zibethinus) Peel

by Astrilia Damayanti, Ria Wulansarie, Zuhriyan Ash Shiddieqy Bahlawan, Suharta, Mutia Royana, Mikhaella Wai Nostra Mannohara Basuki, Bayu Nugroho and Ahmad Lutvi Andri

ChemEngineering 2023, 7(5), 75; https://doi.org/10.3390/chemengineering7050075 - 22 Aug 2023

Viewed by 1233

Abstract

The availability of fossil energy is dwindling, so renewable fuels are the alternative choices, one of which is bioethanol. To increase the purity of the ethanol produced via the fermentation process, activated carbon (AC) was made from durian (Durio zibethinus) peel. [...] Read more.

The availability of fossil energy is dwindling, so renewable fuels are the alternative choices, one of which is bioethanol. To increase the purity of the ethanol produced via the fermentation process, activated carbon (AC) was made from durian (Durio zibethinus) peel. The steps for making AC consist of carbonization (300 °C and 400 °C), chemical activation using phosphoric acid (10–40%), pyrolysis (700 °C and 800 °C), and neutralization. The results showed that the maximum surface area (326.72 m²/g) was obtained from 400 °C carbonization, 800 °C pyrolysis, and activation using a 40% phosphoric acid solution. Other characteristics are the surface area of 326.72 m²/g, pore radius of 1.04 nm, and total pore volume of 0.17 cc/g with phosphate residue in the form a P₂O₅ molecule of 3.47% by weight, with COOH, OH, CO, C=C, C=O, P-OC, and Fe-O groups with wavenumbers (cm⁻¹), respectively, of 3836, 3225, 2103, 1555, 1143, and 494. The AC also demonstrated the highest number of carbon (86.41%) upon detection using EDX, while XRF analysis verified an average carbon content of 94.45 wt%. The highest ethanol adsorption efficiency (%) and the lowest yield (%) of AC (%) were 90.01 ± 0.00 and 23.26 ± 0.01. This study shows that durian peel has great potential as the raw material for the activated carbon manufacture of ethanol adsorbents. Full article

► Show Figures

Figure 1

Journal Menu

Journal Browser

ChemEngineering, Volume 7, Issue 5 (October 2023) – 27 articles

Further Information

Guidelines

MDPI Initiatives

Follow MDPI