Processes

28 pages, 1824 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Phytoremediaton Strategies for Co-Contaminated Soils: Overcoming Challenges, Enhancing Efficiency, and Exploring Future Advancements and Innovations

by Yun-Yeong Lee, Kyung-Suk Cho and Jeonghee Yun

Processes 2025, 13(1), 132; https://doi.org/10.3390/pr13010132 - 6 Jan 2025

Cited by 2 | Viewed by 1918

Abstract

Soils co-contaminated with petroleum hydrocarbons (PHs) and heavy metals pose significant challenges, such as reduced bioavailability of pollutants, toxic effects on soil microorganisms, and unpredictable chemical interactions. These complex interactions hinder effective remediation. Phytoremediation, which utilizes plant and microbial processes, offers a sustainable [...] Read more.

Soils co-contaminated with petroleum hydrocarbons (PHs) and heavy metals pose significant challenges, such as reduced bioavailability of pollutants, toxic effects on soil microorganisms, and unpredictable chemical interactions. These complex interactions hinder effective remediation. Phytoremediation, which utilizes plant and microbial processes, offers a sustainable and eco-friendly approach. However, its effectiveness is often constrained by the intricate interplay among PHs, heavy metals, and soil components, which complicates pollutant degradation and microbial activity. This review explores the interactions between enhancement strategies, including soil amendments, plant growth-promoting bacteria (PGPB), and genetic engineering, which can synergistically enhance pollutant degradation and remediation efficiency. Key challenges include competition for soil adsorption sites among contaminants, microbial community disruptions, and environmental variability. Moreover, the limitations of these strategies, including their reliance on specific plant species, sensitivity to environmental variability, and the necessity for long-term monitoring, are discussed. The proposed solutions focus on integrating emerging technologies and interdisciplinary approaches to overcome these challenges and improve pollutant removal efficiency. Future advancements in interdisciplinary approaches, integrating biological techniques with technological innovations, are highlighted as key to addressing the complexities of co-contaminated environments and improving pollutant removal efficiency. Full article

(This article belongs to the Special Issue Advances in Solid Waste Treatment and Design (2nd Edition))

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12 pages, 6604 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Study on the Influence of the Type of Groove on the Inner Surface of the Casing on the Gas Sealing Performance of Sn58Bi Alloy Plugs

by Chunqing Zha, Tengfei Cui, Wei Wang and Gonghui Liu

Processes 2025, 13(1), 103; https://doi.org/10.3390/pr13010103 - 3 Jan 2025

Viewed by 554

Abstract

Aiming at the problem of the cement hydration shrinkage phenomenon, which occurs when cement seals downhole casing in the process of Carbon Capture, Utilization, and Storage (CCUS) technology, this paper proposes a method of sealing the casing by combining threaded casing with bismuth–tin [...] Read more.

Aiming at the problem of the cement hydration shrinkage phenomenon, which occurs when cement seals downhole casing in the process of Carbon Capture, Utilization, and Storage (CCUS) technology, this paper proposes a method of sealing the casing by combining threaded casing with bismuth–tin alloy. The effect of different types of grooves (square-, trapezoidal-, and screw-threaded grooves) set on the inner surface of the casing on the gas sealing performance of the alloy plug was analyzed. And the effect of the overlay pressure on the gas sealing performance of the alloy plug during the molding process was analyzed. The experimental results show that under 0.2 MPa overlay pressure, the gas breakthrough pressure values of alloy plugs in square-threaded, screw-threaded, trapezoidal-threaded, and smooth hole casings are 5, 3.7, 2.9, and 1 MPa, respectively. When the pitch in the screw-threaded casing is half of the original, the gas breakthrough pressure value of the alloy plugs in the casing is 4.7 MPa. And after the application of 0.2 MPa overlay pressure, the gas sealing performance of the alloy plugs in the screw-threaded, trapezoidal-threaded, and light hole casings was improved by 220%, 230%, and 100%, respectively. The experimental results show that when the grooves are set on the inner surface of the casing, the gas flow path per unit length of the alloy plug-casing interface is prolonged, and the grooves increase the degree of zigzagging on the inner surface of the casing. The gas sealing performance of the alloy plugs is greatly enhanced. This research can provide theoretical support for the application of downhole Carbon Storage using Sn58Bi in casing. Full article

(This article belongs to the Special Issue Oil and Gas Well Engineering: Experimental and Numerical Investigation)

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19 pages, 2758 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Effect of UV Exposure Time on the Properties of Films Prepared from Biotechnologically Derived Chicken Gelatin

by Jakub Martinek, Lucie Polomíková, Michal Kudláček, Jana Navrátilová, Pavel Mokrejš, Jana Pavlačková and Robert Gál

Processes 2025, 13(1), 91; https://doi.org/10.3390/pr13010091 - 2 Jan 2025

Viewed by 1293

Abstract

Biomaterials (films, foils, fibers, coatings) based on proteins are becoming increasingly important due to the growing applications for which pork and beef gelatins are used. Alternative types of gelatins (poultry or fish), which have not yet been sufficiently tested, represent a high potential. [...] Read more.

Biomaterials (films, foils, fibers, coatings) based on proteins are becoming increasingly important due to the growing applications for which pork and beef gelatins are used. Alternative types of gelatins (poultry or fish), which have not yet been sufficiently tested, represent a high potential. This study looks at the effect of different UV exposure times on chicken gelatin films with added glycerol. The gelatin was prepared using a unique enzymatic hydrolysis process. The quality of the UV-exposed films was compared with gelatin films not exposed to UV light. Radiation-induced crosslinking improved the mechanical and physical properties of the films. The UV crosslinked films are stabilized at a degree of swelling from 700 to 900%; moreover, they extend their dissolution to more than 7 days while maintaining their original shape. In contrast, non-crosslinked films swell and dissolve in water faster. Further, the effect of UV radiation on the water vapor permeability and color of the films was monitored. Water vapor permeability decreased by 2.5 times with increasing crosslinking time for 30% and 40% glycerol content, and the yellowness of the irradiated samples increased with exposure time in the interval from 24 to 28. Using Fourier transform infrared spectroscopy, the differences in the amount of bonding based on irradiation time were analyzed. As a result of crosslinking, the intensity of existing bonds increased. Thermal properties were verified through differential scanning calorimetry and thermogravimetric analysis. The results proved that chicken gelatin is suitable for preparing films in foods and medicine. Applying UV radiation to crosslink gelatin films is an alternative to traditionally used chemical crosslinkers. Full article

(This article belongs to the Special Issue Features, Reviews and Perspectives for the 10th Anniversary of Processes)

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22 pages, 4995 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

3D Printed Ni–Cu Sodalite Catalysts for Sustainable γ-Valerolactone Production from Levulinic Acid—Effect of the Copper Content and the Method of Preparation

by Margarita Popova, Boian Mladenov, Ivan Dimitrov, Momtchil Dimitrov, Violeta Mitova, Yavor Mitrev, Daniela Kovacheva, Nikolay Velinov, Daniela Karashanova and Silviya Boycheva

Processes 2025, 13(1), 72; https://doi.org/10.3390/pr13010072 - 1 Jan 2025

Viewed by 1412

Abstract

Coal fly ash zeolites with Sodalite structure were synthesized by ultrasound-assisted double stage fusion-hydrothermal synthesis. Monometallic Ni and bimetallic Ni–Cu supported catalysts with 5 wt.% Ni and different copper contents of 1.5, 2.5 and 5.0 wt.% Cu were prepared by post-synthesis incipient wetness [...] Read more.

Coal fly ash zeolites with Sodalite structure were synthesized by ultrasound-assisted double stage fusion-hydrothermal synthesis. Monometallic Ni and bimetallic Ni–Cu supported catalysts with 5 wt.% Ni and different copper contents of 1.5, 2.5 and 5.0 wt.% Cu were prepared by post-synthesis incipient wetness impregnation. The catalysts were characterized by X-ray powder diffraction, N₂ physisorption, transmission electron microscopy (TEM), Mössbauer spectroscopy and H₂ temperature programmed reduction analysis. It was found that crystalline Cu⁰ and Ni_xCu_y intermetallic nanoparticles were formed in the reduced powder and 3D printed catalysts and that they affected the reducibility of the catalytically active nickel phase. Three-dimensionally printed 5Ni2.5Cu/Sodalite catalysts were prepared via modification with metals before and after 3D printing for comparative studies. The powder and 3D printed catalysts were studied in the lignocellulosic biomass-derived levulinic acid (LA) to γ-valerolactone (GVL). The formation of NiCu alloy, which is found on the powder and 3D printed catalysts, favors their catalytic performance in the studied reaction. In contrast with powder catalysts, the preservation of the Sodalite structure was detected for all 3D printed samples and was found to have a positive influence on the metal dispersion registered in the 3D spent catalysts. The powder 5Ni2.5Cu/Sodalite catalyst showed the highest LA conversion and high GVL yield at 150 °C reaction temperature. Three-dimensionally printed catalysts show more stable catalytic activity than powder catalysts due to the preservation of the zeolite structure and metal dispersion. Full article

(This article belongs to the Special Issue Preparation, Characterization and Application of Heterogeneous Catalysts)

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22 pages, 6455 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Process Improvement and Economic and Environmental Evaluation of Bio-Hydrogenated Diesel Production from Refined Bleached Deodorized Palm Oil

by Amata Anantpinijwatna, Lida Simasatitkul, Kanokporn Yooyen, Suksun Amornraksa, Suttichai Assabumrungrat and Karittha Im-orb

Processes 2025, 13(1), 75; https://doi.org/10.3390/pr13010075 - 1 Jan 2025

Viewed by 1517

Abstract

The co-production of BHD with other renewable fuels (i.e., using a novel process involving carbon dioxide utilization to achieve the global sustainability goal) is presented. The three configurations of BHD production from refined bleached deodorized palm oil (RBDPO), including (1) the conventional BHD [...] Read more.

The co-production of BHD with other renewable fuels (i.e., using a novel process involving carbon dioxide utilization to achieve the global sustainability goal) is presented. The three configurations of BHD production from refined bleached deodorized palm oil (RBDPO), including (1) the conventional BHD process with hydrogen recovery (BHD process), (2) the BHD process coupled with the Fischer–Tropsch process (BHD-FT process), and (3) the BHD process coupled with the bio-jet fuel and methanol processes (BHD-BIOJET-MEOH process) are investigated using the process model developed in Aspen Plus. The effect of the operating parameters is studied, and the condition of each process offering the highest BHD yield is proposed. Then, the pinch analysis and heat exchanger network (HEN) design of each proposed process are performed to find the highest energy-efficient configuration. The economic and environmental analysis is later performed to investigate the sustainability performance of each configuration. The conventional BHD process requires less hydrogen and consumes less energy than the others. The BHD-BIOJET-MEOH process is the most economically feasible, offering the highest net present value (NPV) of USD 7.93 million and the shortest payback period of 3 years and 1 month. However, it offers the highest carbon footprint of 0.820 kgCO₂ eq./kg of BHD, and it presented the highest potential environmental impact (PEI) in all categories. Full article

(This article belongs to the Special Issue Process Systems Engineering for Environmental Protection)

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14 pages, 1834 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Comparison of Vacuum and Atmospheric Deep-Fat Frying of Osmo-Dehydrated Goldenberries

by Christiam Guevara-Betancourth, Oscar Arango, Zully J. Suárez-Montenegro, Diego F. Tirado and Oswaldo Osorio

Processes 2025, 13(1), 50; https://doi.org/10.3390/pr13010050 - 29 Dec 2024

Viewed by 628

Abstract

Colombian goldenberries that do not reach sufficient quality for export are exposed to waste, so the search for processes that provide added value while guaranteeing the conservation of this fruit is paramount. Thus, snacks by vacuum frying from goldenberries (Physalis peruviana L.) [...] Read more.

Colombian goldenberries that do not reach sufficient quality for export are exposed to waste, so the search for processes that provide added value while guaranteeing the conservation of this fruit is paramount. Thus, snacks by vacuum frying from goldenberries (Physalis peruviana L.) with low export quality were made. Goldenberry slices previously subjected to ultrasound-assisted osmotic dehydration were used for this purpose. Response surface methodology with different levels of temperature (110 °C and 130 °C), vacuum pressure (0.3 bar and 0.5 bar), and time (2 min and 6 min) was used to optimize the process. At optimal vacuum frying conditions (i.e., 108 °C, 0.5 bar, and 5.5 min), snacks with lower (p ≤ 0.05) oil content were produced, compared to atmospheric frying chips. The optimized snacks had 9% oil, 7% moisture, ΔE of 13 (with respect to fresh fruit), a_w of 0.3, and hardness of 14 N. The kinetics and modeling of moisture loss and oil uptake were performed under optimal conditions, obtaining the best fit with the Page (R² = 99%) and the first-order (R² = 96%) models, respectively. There was a clear correlation between oil uptake and moisture loss, as the highest oil retention in the product took place when the product had lost the greatest amount of water; therefore, the low initial moisture in the product due to pretreatment resulted in lower oil uptake in it. The obtained goldenberry snack showed adequate physicochemical properties, and the pretreatment yielded a product with much healthier characteristics (i.e., lower oil content, and therefore, a lower caloric intake); so, the proposed process could represent an alternative to the processing of low-export quality Colombian goldenberries. Full article

(This article belongs to the Special Issue Design of Food Processing and Technologies: Studies on Physical Properties, Thermodynamics, Rheology and Emulsification)

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21 pages, 1353 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Tackling Old Challenges in Microalgal Biotechnology: The Role of Photobioreactors to Advance the Technology Readiness Level

by Mariany Costa Deprá, Rosangela Rodrigues Dias, Leila Queiroz Zepka and Eduardo Jacob-Lopes

Processes 2025, 13(1), 51; https://doi.org/10.3390/pr13010051 - 29 Dec 2024

Viewed by 1407

Abstract

Microalgae biotechnology has taken the world by storm. However, despite its great potential promise, it still cannot be considered a fully consolidated technology due to a crucial challenge: the low rates of biomass productivity. To overcome this hurdle, photobioreactors have been developed as [...] Read more.

Microalgae biotechnology has taken the world by storm. However, despite its great potential promise, it still cannot be considered a fully consolidated technology due to a crucial challenge: the low rates of biomass productivity. To overcome this hurdle, photobioreactors have been developed as an innovative solution, promising to increase the efficiency of microalgae cultures by providing optimized conditions. However, the results obtained with these systems do not always meet initial expectations, and their large-scale implementation faces complex technical challenges. In light of this, the present review addresses the main aspects related to the design and engineering of photobioreactors, highlighting their potentialities and limitations in overcoming the critical challenges of microalgal biotechnology. Furthermore, we discuss the current technological readiness level and the commercial readiness index of microalgae-based bioproducts from the perspective of industrial-scale production. Full article

(This article belongs to the Special Issue Bioreactor Design and Optimization Process)

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33 pages, 9196 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Generic Representation Language for Modeling Transport and Material Handling Systems in Smart Manufacturing Systems

by Micael Gonçalves, Paulo Martins, Guilherme Pereira and Rui Sousa

Processes 2025, 13(1), 43; https://doi.org/10.3390/pr13010043 - 27 Dec 2024

Viewed by 689

Abstract

This paper introduces a generic representation language to be used by organizations to represent physical and behavioral characteristics of Transport and Material Handling Systems (TMHS). This work implied a systematic observation, analysis and interpretation of several TMHS to ensure that most of the [...] Read more.

This paper introduces a generic representation language to be used by organizations to represent physical and behavioral characteristics of Transport and Material Handling Systems (TMHS). This work implied a systematic observation, analysis and interpretation of several TMHS to ensure that most of the behaviors were covered. The generic representation language consists of three main types of elements: (i) objects transported, (ii) workstations and (iii) transport/handling equipment (device), and a small set of simple and easy-to-use properties to be defined by users of each organization to characterize each element of a TMHS. Each property is not related to any specific device and can be used to represent the behavior of different devices. A graphic representation for each element is proposed to make communication between users simpler and more effective, as well as to reduce the time to learn and apply the representation language. The representation of three concrete TMHS (with different behaviors, rules and restrictions) is shown, contributing to demonstrate the ability, flexibility and comprehensiveness of the developed representation language. These results point to the potential of implementing the developed generic representation language in IT (Information Technology) support systems, in particular, in Smart Manufacturing Systems, to control most of the TMHS. Full article

(This article belongs to the Special Issue Process Automation and Smart Manufacturing in Industry 4.0/5.0)

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33 pages, 2306 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Control of Heat-Integrated Distillation Columns: Review, Trends, and Challenges for Future Research

by Nura Musa Tahir, Jie Zhang and Matthew Armstrong

Processes 2025, 13(1), 17; https://doi.org/10.3390/pr13010017 - 25 Dec 2024

Cited by 1 | Viewed by 2360

Abstract

Heat-integrated distillation columns (HIDiC) are well known for their high energy efficiency, which has been demonstrated through thorough model-based simulation and practical testing. Despite this advantage, HIDiC systems are fundamentally complicated and provide major hurdles, particularly in terms of dynamic control, complicating their [...] Read more.

Heat-integrated distillation columns (HIDiC) are well known for their high energy efficiency, which has been demonstrated through thorough model-based simulation and practical testing. Despite this advantage, HIDiC systems are fundamentally complicated and provide major hurdles, particularly in terms of dynamic control, complicating their industrial implementation. Ongoing research is critical to improving their stability and scalability, allowing for wider incorporation into industrial processes. This review focuses on the fundamental aspects of HIDiC systems, such as heat transfer models, design improvements, experimental research, modelling, simulation, optimization, and process control techniques. This paper summarizes the present status of research and identifies significant technological obstacles that must be overcome to increase the functionality and industrial applications of HIDiC technology. In response to the increased demand for energy-efficient industrial processes, the analysis also investigates current developments in HIDiC control and optimization methodologies. It evaluates several control approaches, both model-based and data-driven, and their capacity to handle the dynamic complexities seen in HIDiC systems. Furthermore, this paper discusses the most recent optimization efforts targeted at improving product purity, operational flexibility, and overall energy efficiency. Full article

(This article belongs to the Section Chemical Processes and Systems)

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27 pages, 6978 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Tool Wear State Monitoring in Titanium Alloy Milling Based on Wavelet Packet and TTAO-CNN-BiLSTM-AM

by Zongshuo Yang, Li Li, Yunfeng Zhang, Zhengquan Jiang and Xuegang Liu

Processes 2025, 13(1), 13; https://doi.org/10.3390/pr13010013 - 24 Dec 2024

Viewed by 893

Abstract

To effectively monitor the nonlinear wear variation of tools during the processing of titanium alloys, this study proposes a hybrid deep neural network fault diagnosis model that integrates the triangulation topology aggregation optimizer (TTAO), convolutional neural network (CNN), bidirectional long short-term memory network [...] Read more.

To effectively monitor the nonlinear wear variation of tools during the processing of titanium alloys, this study proposes a hybrid deep neural network fault diagnosis model that integrates the triangulation topology aggregation optimizer (TTAO), convolutional neural network (CNN), bidirectional long short-term memory network (BiLSTM), and attention mechanism (AM). Firstly, vibration signals from the machine tool spindle are acquired and subjected to the wavelet packet transform (WPT) to extract multi-frequency band energy features as model inputs. Then, the CNN and BiLSTM modules capture the features and temporal relationships of the input signals. Finally, introduction of the AM, combined with the TTAO algorithm, automatically extracts deep features, overcoming issues such as local optima and slow convergence in traditional neural networks, thereby enhancing the accuracy and efficiency of tool wear state recognition. The experimental results demonstrate that the proposed model achieves an average accuracy rate of 98.649% in predicting tool wear states, outperforming traditional backpropagation (BP) networks and standard CNN models. Full article

(This article belongs to the Special Issue Green Manufacturing Processes: Data Modelling and Fusion-Driven Optimization Control)

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21 pages, 14267 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Optimisation of Heat Exchanger Performance Using Modified Gyroid-Based TPMS Structures

by Martin Beer and Radim Rybár

Processes 2024, 12(12), 2943; https://doi.org/10.3390/pr12122943 - 23 Dec 2024

Viewed by 1875

Abstract

Triply periodic minimal surfaces (TPMS) represent an innovative approach to the design of heat exchangers, enabling the optimisation of thermal and hydraulic performance. This study presents a comparative analysis of three geometric TPMS configurations: sheet gyroid, skeletal gyroid, and the newly proposed combined [...] Read more.

Triply periodic minimal surfaces (TPMS) represent an innovative approach to the design of heat exchangers, enabling the optimisation of thermal and hydraulic performance. This study presents a comparative analysis of three geometric TPMS configurations: sheet gyroid, skeletal gyroid, and the newly proposed combined gyroid geometry. Using numerical analysis based on simulations of fluid flow and heat transfer, key parameters such as the heat transfer coefficient, Nusselt number, friction factor, Chilton–Colburn j-factor, and pressure drop were evaluated. The results demonstrated that the combined gyroid geometry achieves the highest heat transfer efficiency, exhibiting significant improvements in the Nusselt number and heat transfer coefficient across the entire flow range. Simultaneously, it maintains low pressure losses, making it well suited for applications demanding high thermal performance with minimal energy losses. This study highlights the potential of TPMS geometries for optimising heat exchanger design and opens new paths for their implementation in industrial systems. Full article

(This article belongs to the Special Issue Fluid Dynamics and Processes of Heat Transfer Enhancement)

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13 pages, 2133 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

A Series Arc Fault Diagnosis Method Based on an Extreme Learning Machine Model

by Lichun Qi, Takahiro Kawaguchi and Seiji Hashimoto

Processes 2024, 12(12), 2947; https://doi.org/10.3390/pr12122947 - 23 Dec 2024

Viewed by 754

Abstract

In this study, we address the critical issue of accurately detecting series AC arc faults, which are often challenging to identify due to their small fault currents and can lead to devastating electrical fires. We propose an intelligent diagnosis method based on the [...] Read more.

In this study, we address the critical issue of accurately detecting series AC arc faults, which are often challenging to identify due to their small fault currents and can lead to devastating electrical fires. We propose an intelligent diagnosis method based on the extreme learning machine (ELM) model to enhance detection accuracy and real-time monitoring capabilities. Our approach involves collecting high-frequency current signals from 23 types of loads using a self-developed AC series arc fault data acquisition device. We then extract 14 features from both the time and frequency domains as candidates for arc fault diagnosis, employing a random forest to select the most significantly changed features. Finally, we design an ELM classifier for series arc fault diagnosis, achieving an identification accuracy of 99.00% ± 0.26%. Compared to existing series arc fault diagnosis methods, our ELM-based method demonstrates superior recognition performance. This study contributes to the field by providing a more accurate and efficient diagnostic tool for series AC arc faults, with broad implications for electrical safety and fire prevention. Full article

(This article belongs to the Special Issue Research on Intelligent Fault Diagnosis Based on Neural Network)

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12 pages, 2871 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Recovery of Cellulose Contained in Mixed Fabrics

by Juan A. Conesa and Viviana N. Córdoba

Processes 2024, 12(12), 2854; https://doi.org/10.3390/pr12122854 - 12 Dec 2024

Viewed by 819

Abstract

The present work focuses on the recovery of cellulose from mixed fabrics containing polyester and cotton through the use of different chemical and hydrothermal treatment methods. Through the application of various analytical techniques, such as thermogravimetry (TG) and infrared spectroscopy (IR), we seek [...] Read more.

The present work focuses on the recovery of cellulose from mixed fabrics containing polyester and cotton through the use of different chemical and hydrothermal treatment methods. Through the application of various analytical techniques, such as thermogravimetry (TG) and infrared spectroscopy (IR), we seek to determine the effectiveness of the methods used. The results indicate that different treatments with NaOH and distilled water at high temperatures and pressures are particularly effective for the extraction of the cellulose fraction. Furthermore, these methods were compared with previous studies to evaluate their feasibility and sustainability. The findings underline the importance of selecting appropriate experimental conditions to maximize the purity of the cellulose obtained and minimize fiber degradation, thus promoting more efficient and sustainable textile recycling processes. These results have significant implications for industrial applications by enabling the development of scalable recycling methods and contribute to reducing the environmental impact of textile waste. Full article

(This article belongs to the Special Issue Novel Recovery Technologies from Wastewater and Waste)

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15 pages, 6815 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Numerical Study of Biomass Combustion Using a Transient State Approach

by Filipe Neves, Armando A. Soares and Abel Rouboa

Processes 2024, 12(12), 2800; https://doi.org/10.3390/pr12122800 - 7 Dec 2024

Viewed by 893

Abstract

The behavior of the temperature and velocity, as well as the mass fraction of water (H₂O) and wood inside a combustion chamber under specific operating conditions, were numerically investigated using a transient state model. For the computational fluid dynamics (CFD) simulation, [...] Read more.

The behavior of the temperature and velocity, as well as the mass fraction of water (H₂O) and wood inside a combustion chamber under specific operating conditions, were numerically investigated using a transient state model. For the computational fluid dynamics (CFD) simulation, the software Ansys Fluent 2024 R2 was used to analyze a turbulent flow in two dimensions. The species transport with volumetric responses and eddy dissipation were included in the combustion simulation. The study was conducted for the first 150 s. The findings show that in the lower and upper zones of the combustion chamber close to the walls, the temperature rises over time. The velocity between the outlets rises over time. Due to the fact that the wood goes through a process that reduces the amount of wood and produces H₂O, it exhibits the opposite behavior for the mass fractions of wood and H₂O. Full article

(This article belongs to the Special Issue Progress on Biomass Processing and Conversion)

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12 pages, 2546 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

The Characterization of the Alcoholic Fermentation Process in Wine Production Based on Acoustic Emission Analysis

by Angel Sanchez-Roca, Juan-Ignacio Latorre-Biel, Emilio Jiménez-Macías, Juan Carlos Saenz-Díez and Julio Blanco-Fernández

Processes 2024, 12(12), 2797; https://doi.org/10.3390/pr12122797 - 7 Dec 2024

Viewed by 996

Abstract

The present experimental study assessed the viability of utilizing an acoustic emission signal as a monitoring instrument to predict the chemical characteristics of wine throughout the alcoholic fermentation process. The purpose of this study is to acquire the acoustic emission signals generated by [...] Read more.

The present experimental study assessed the viability of utilizing an acoustic emission signal as a monitoring instrument to predict the chemical characteristics of wine throughout the alcoholic fermentation process. The purpose of this study is to acquire the acoustic emission signals generated by CO₂ bubbles to calculate the must density and monitor the kinetics of the alcoholic fermentation process. The kinetics of the process were evaluated in real time using a hydrophone immersed in the liquid within the fermentation tank. The measurements were conducted in multiple fermentation tanks at a winery engaged in the production of wines bearing the Rioja Denomination of Origin (D.O.) designation. Acoustic signals were acquired throughout the entirety of the fermentation process, via a sampling period of five minutes, and stored for subsequent processing. To validate the results, the measurements obtained manually in the laboratory by the winemaker were collected during this stage. Signal processing was conducted to extract descriptors from the acoustic signal and evaluate their correlation with the experimental data acquired during the process. The results of the analyses confirm that there is a high linear correlation between the density data obtained from the acoustic analysis and the density data obtained at the laboratory level, with determination coefficients exceeding 95%. The acoustic emission signal is a valuable decision-making tool for technicians and winemakers due to its sensitivity when describing variations in kinetics and density during the alcoholic fermentation process. Full article

(This article belongs to the Special Issue Processing Foods: Process Optimization and Quality Assessment, 3rd Edition)

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20 pages, 2541 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Towards Flexible Control of Production Processes: A Requirements Analysis for Adaptive Workflow Management and Evaluation of Suitable Process Modeling Languages

by Alexander Schultheis, David Jilg, Lukas Malburg, Simon Bergweiler and Ralph Bergmann

Processes 2024, 12(12), 2714; https://doi.org/10.3390/pr12122714 - 1 Dec 2024

Viewed by 977

Abstract

In the context of Industry 4.0, Artificial Intelligence (AI) methods are used to maximize the efficiency and flexibility of production processes. The adaptive management of such semantic processes can optimize energy and resource efficiency while providing high reliability, but it depends on the [...] Read more.

In the context of Industry 4.0, Artificial Intelligence (AI) methods are used to maximize the efficiency and flexibility of production processes. The adaptive management of such semantic processes can optimize energy and resource efficiency while providing high reliability, but it depends on the representation type of these models. This paper provides a literature review of current Process Modeling Languages (PMLs). Based on a suitable PML, the flexibility of production processes can be increased. Currently, a common understanding of this process flexibility in the context of adaptive workflow management is missing. Therefore, requirements derived from the business environment are presented for process flexibility. To enable the identification of suitable PLMs, requirements regarding this are also raised. Based on these, the PMLs identified in the literature review are evaluated. Thereby, based on a preselection, a detailed examination of the seven most promising languages is performed, including an example from a real smart factory. As a result, a recommendation is made for the use of BPMN, for which it is presented how it can be enriched with separate semantic information that is suitable for the use of AI planning and, thus, enables flexible control. Full article

(This article belongs to the Special Issue AI-Supported Methods and Process Modeling in Smart Manufacturing)

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14 pages, 4014 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Performance Analysis of Effective Methylene Blue Immobilization by Carbon Microspheres Obtained from Hydrothermally Processed Fructose

by Sanja S. Krstić, Đuro Čokeša, Radojka T. Vujasin, Branka V. Kaluđerović, Milan Z. Momčilović, Darko Jaćimovski, Pavel Gurikov and Vladimir M. Dodevski

Processes 2024, 12(12), 2683; https://doi.org/10.3390/pr12122683 - 28 Nov 2024

Viewed by 695

Abstract

Carbon microspheres have been synthesized by the hydrothermal method with fructose and a phosphoric acid solution at two different concentrations, which were used as precursors. The obtained materials were characterized by elemental analysis, X-ray powder diffraction (XRPD) analysis, scanning electron microscopy (SEM), nitrogen [...] Read more.

Carbon microspheres have been synthesized by the hydrothermal method with fructose and a phosphoric acid solution at two different concentrations, which were used as precursors. The obtained materials were characterized by elemental analysis, X-ray powder diffraction (XRPD) analysis, scanning electron microscopy (SEM), nitrogen adsorption/desorption measurements, and Fourier transform infrared (FTIR) spectroscopy. Batch sorption experiments were performed to remove methylene blue (MB) from aqueous solutions by varying the initial concentration of MB (C₀) from 50 to 500 mg/dm³, contact period, solution pH value, and temperature. Prepared sorbents consisted of microsphere particles with diameters in the range of 0.6–2.7 µm. The synthetic route was found to govern the microporous–mesoporous structure and surface acidic functional groups of the final product. A phosphoric acid concentration of 40 wt.% gave carbon material with a specific surface area of 932 m²/g and a total pore volume of 0.43 cm³/g. It was found that the extent of MB sorption by the obtained carbon microspheres increased with initial dye concentration, contact time, and especially solution pH but slightly decreased with increasing temperature. Kinetic studies showed that the dye sorption process followed pseudo-second-order kinetics. Full article

(This article belongs to the Special Issue Biomass Treatment and Pyrolysis Processes)

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26 pages, 13041 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Carbon-Free H₂ Production from Ammonia Decomposition over 3D-Printed Ni-Alloy Structures Activated with a Ru/Al₂O₃ Catalyst

by Cristina Italiano, Gabriel Marino, Minju Thomas, Benjamin Hary, Steve Nardone, Simon Richard, Assia Saker, Damien Tasso, Nicolas Meynet, Pierre Olivier, Fausto Gallucci and Antonio Vita

Processes 2024, 12(12), 2663; https://doi.org/10.3390/pr12122663 - 26 Nov 2024

Viewed by 1915

Abstract

Hydrogen, with its high energy density and zero greenhouse gas emissions, is an exceptional energy vector, pivotal for a sustainable energy future. Ammonia, serving as a practical and cost-effective hydrogen carrier, offers a secure method for hydrogen storage and transport. The decomposition of [...] Read more.

Hydrogen, with its high energy density and zero greenhouse gas emissions, is an exceptional energy vector, pivotal for a sustainable energy future. Ammonia, serving as a practical and cost-effective hydrogen carrier, offers a secure method for hydrogen storage and transport. The decomposition of ammonia into hydrogen is a crucial process for producing green hydrogen, enabling its use in applications ranging from clean energy generation to fueling hydrogen-powered vehicles, thereby advancing the transition to a carbon-free energy economy. This study investigates the catalytic performance of various 3D-printed porous supports based on periodic open cellular structures (POCS) and triply periodic minimal surface (TPMS) architecture manufactured from IN625 nickel alloy powder using the laser powder bed fusion (LPBF) technique. The POCS and TPMS, featuring geometries including BCC, Kelvin, and Gyroid, were analyzed for cell size, strut/sheet diameter, porosity, and specific surface area. Pressure drop analyses demonstrated correlations between structural parameters and fluid dynamics, with BCC structures exhibiting lower pressure drops due to their higher porosity and the open channel network. The dip/spin coating method was successfully applied to activate the supports with a commercial Ru/Al₂O₃ catalyst, achieving uniform coverage crucial for catalytic performance. Among the tested geometries, the Gyroid structure showed superior catalytic activity towards ammonia decomposition, attributed to its efficient mass transfer pathways. This study highlights the importance of structural design in optimizing catalytic processes and suggests the Gyroid structure as a promising candidate for improving reactor efficiency and compactness in hydrogen production systems. Full article

(This article belongs to the Special Issue 10th Anniversary of Processes: Design of the Chemical Industry of the Future)

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21 pages, 14871 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Electrochemical Co-Degradation of Acetaminophen and Bisphenol A in Aqueous Solutions: Degradation Competition and Pathways

by Kuo-Lin Huang, Jui-Chiung Hung and Yi-Ming Kuo

Processes 2024, 12(12), 2641; https://doi.org/10.3390/pr12122641 - 23 Nov 2024

Viewed by 1088

Abstract

This study investigated the degradation competition and pathways of electrochemical co-degradation of two emerging environmental contaminants, polar acetaminophen (AP) and (moderately) non-polar bisphenol A (BPA), on a boron-doped diamond (BDD) electrode in aqueous solutions. The results showed that both compounds mainly relied on [...] Read more.

This study investigated the degradation competition and pathways of electrochemical co-degradation of two emerging environmental contaminants, polar acetaminophen (AP) and (moderately) non-polar bisphenol A (BPA), on a boron-doped diamond (BDD) electrode in aqueous solutions. The results showed that both compounds mainly relied on hydroxyl radicals (•OH) to trigger indirect oxidation for their electrochemical degradation, although AP also underwent direct oxidation during electrolysis. The effect of increasing current density on the increases in degradation performance was almost the same for AP and BPA. However, BPA exhibited a better performance in mono-degradation than AP, while the opposite tendency was observed for their co-degradation. Their degradation efficiencies were better in 1 M Na₂SO₄ solution than in a real water matrix. Both UV-vis and excitation–emission matrix (EEM) fluorescence analyses demonstrated that all the aromatic rings of AP and BPA were opened after 30 min of electrolysis at 0.5 A cm⁻² in 1 M Na₂SO₄ solution. Regardless of the small difference in intermediate species, the pathways of electrochemical AP+BPA co-degradation were similar to those of their mono-degradation combination. A double exponential decay model is proposed to simulate the formation and degradation rate constants of benzoquinone (an intermediate). Full article

(This article belongs to the Topic Wastewater Treatment Based on AOPs, ARPs, and AORPs)

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12 pages, 1934 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Pyrolysis of Hydrothermal Sewage Sludge and Food Waste Digestate for Heavy Metals Stabilization and Ecological Risk Reduction

by Yu Wang, Ruming Wang and Guangyi Zhang

Processes 2024, 12(12), 2614; https://doi.org/10.3390/pr12122614 - 21 Nov 2024

Viewed by 935

Abstract

The application of municipal sewage sludge is often limited by concerns over heavy metal (HM) safety. This study explored the reduction of HM content in hydrothermal sewage sludge (HTS) through co-pyrolysis with food waste digestate (FD), aiming to lower ecological risks in the [...] Read more.

The application of municipal sewage sludge is often limited by concerns over heavy metal (HM) safety. This study explored the reduction of HM content in hydrothermal sewage sludge (HTS) through co-pyrolysis with food waste digestate (FD), aiming to lower ecological risks in the produced biochar. Results indicated that FD addition effectively lowered HM concentrations in biochar, mainly via dilution effect. Moreover, increased pyrolysis temperatures and FD addition promoted the stabilization of Cr, Ni, Cu, Zn, As, Cd, and Pb. Notably, a 50% FD mix significantly increased the proportion of HMs in the residual fraction of Ni (75.66%), Cu (71.66%), Zn (98.13%), and Cd (58.14%) compared to solo pyrolysis at 700 °C. Consequently, the potential ecological risk index significantly dropped from 47.86 to 26.29. Biochar created under optimal conditions (700 °C with a 50% FD ratio) showcased improved application prospects due to reduced bioavailability, thus diminishing HM-related ecological dangers. Full article

(This article belongs to the Special Issue Advanced Biomass Analysis and Conversion Technology)

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12 pages, 2098 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Production, Characterization and Application of Biosurfactant for Cleaning Cotton Fabric and Removing Oil from Contaminated Sand

by Renata R. Silva, Maria C. F. Caldas, Carlos V. A. Lima, Hugo M. Meira, Leonie A. Sarubbo and Juliana M. Luna

Processes 2024, 12(11), 2584; https://doi.org/10.3390/pr12112584 - 18 Nov 2024

Cited by 1 | Viewed by 1122

Abstract

Biosurfactants are a group of environmentally friendly amphiphilic molecules that are applicable in numerous industries as essential biotechnology products, such as food production, cleaning products, pharmacology, cosmetics, pesticides, textiles and oil and gas fields. In this sense, and knowing the potential of these [...] Read more.

Biosurfactants are a group of environmentally friendly amphiphilic molecules that are applicable in numerous industries as essential biotechnology products, such as food production, cleaning products, pharmacology, cosmetics, pesticides, textiles and oil and gas fields. In this sense, and knowing the potential of these biomolecules, the aim of this work was to produce a biosurfactant, characterize it regarding its chemical and surfactant properties and investigate its potential in the removal of contaminants and in the cleaning of cotton fabrics. The biosurfactant was initially obtained from the cultivation of the microorganism Candida glabrata UCP 1002 in medium containing distilled water with 2.5% residual frying oil, 2.5% molasses and 2.5% corn steep liquor agitated at 200 rpm for 144 h. The biosurfactant reduced the surface tension of water from 72 to 29 mN/m. The toxicity potential of the biosurfactant was evaluated using Tenebrio molitor larvae and demonstrated non-toxicity. The biosurfactant was applied as a degreaser of engine oil on cotton fabric, and showed 83% (2× CMC), 74% (1× CMC) and 78% (1/2× CMC) oil removal. Therefore, the biosurfactant produced in this work has promising surfactant and emulsifying properties with potential for application in various industrial segments. Full article

(This article belongs to the Special Issue Advancements in Biosurfactants: Production, Characterization and Multifaceted Applications)

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19 pages, 318 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Recovery of Lesser-Known Strategic Metals: The Gallium and Germanium Cases

by Jose Ignacio Robla, Manuel Alonso and Francisco Jose Alguacil

Processes 2024, 12(11), 2545; https://doi.org/10.3390/pr12112545 - 14 Nov 2024

Cited by 1 | Viewed by 2739

Abstract

Being not as popular as other elements, such as cobalt, lithium, and rare earth elements, both gallium and germanium have wide use in target developments/industries, thus making them valuable and strategically critical metals. The principal sources for the recovery of both metals are [...] Read more.

Being not as popular as other elements, such as cobalt, lithium, and rare earth elements, both gallium and germanium have wide use in target developments/industries, thus making them valuable and strategically critical metals. The principal sources for the recovery of both metals are secondary wastes of the bauxite (gallium) or zinc (germanium) industries; also, their recycling from waste materials is necessary. The characteristics of these materials make hydrometallurgical operations widely useful in recovering both gallium and germanium from the various sources containing them. The present work reviews the most recent applications (in 2024) of the various operations applied to the recovery of gallium or germanium from various resources. Full article

(This article belongs to the Special Issue Features, Reviews and Perspectives for the 10th Anniversary of Processes)

21 pages, 10123 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Development of an FEM for the Combined Electromagnetic and Hydraulic Forming Process Based on Experimental Data

by Yoonho Jang and Jeong Kim

Processes 2024, 12(11), 2520; https://doi.org/10.3390/pr12112520 - 12 Nov 2024

Viewed by 792

Abstract

Electrohydraulic forming (EHF) which demonstrates reduced bouncing effect, formation in narrow areas, and no effect on the electrical conductivity of the blank can overcome the shortcomings of deep drawing and electromagnetic forming. However, considerable time is involved in evaluating the possibility of forming [...] Read more.

Electrohydraulic forming (EHF) which demonstrates reduced bouncing effect, formation in narrow areas, and no effect on the electrical conductivity of the blank can overcome the shortcomings of deep drawing and electromagnetic forming. However, considerable time is involved in evaluating the possibility of forming a specific part through experiments. Developing an accurate finite element model can reduce the opportunity costs of an experiment by reducing unnecessary trial and error in forming a specific part. In this study, the chamber, die, and blank components of the EHF experimental equipment in our laboratory were reverse-modeled using CATIA V5R18. Subsequently, the IGES format of the components was imported into LS-DYNA R12, and an FEM model to simulate the EHF experiment was constructed. The experimental and simulation results of nine cases, based on the SUS430 material, input voltage, and blank thickness, were compared for model verification. The forming results for all cases in the constructed finite element analysis model nearly matched the experimental results. Moreover, the linear increase in the blank thickness with input voltage and thickness was simultaneously confirmed. In a computing environment using a 4.3 GHz, 24-Core CPU and 64 GB memory, the time required for one finite element analysis was approximately 1 h. Full article

(This article belongs to the Special Issue Advances in Electromagnetic Energy Applications for Sustainable Processes)

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23 pages, 1994 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Exploring Recent Advances in Lignocellulosic Biomass Waste Delignification Through the Combined Use of Eutectic Solvents and Intensification Techniques

by Cristina Álvarez, Aleta Duque, Andrea Sánchez-Monedero, Emilio J. González, María González-Miquel and Raquel Cañadas

Processes 2024, 12(11), 2514; https://doi.org/10.3390/pr12112514 - 12 Nov 2024

Cited by 1 | Viewed by 2435

Abstract

Growing awareness of resource sustainability and waste management has driven the search for circular-economy solutions. Lignocellulosic biomass waste, the most abundant renewable carbon resource, offers green potential as an alternative to declining non-renewable fuels. However, due to its recalcitrant nature, it requires pre-processing [...] Read more.

Growing awareness of resource sustainability and waste management has driven the search for circular-economy solutions. Lignocellulosic biomass waste, the most abundant renewable carbon resource, offers green potential as an alternative to declining non-renewable fuels. However, due to its recalcitrant nature, it requires pre-processing to convert it into valuable products like energy and chemicals. Biorefineries play a key role in this process by promoting the integral use of biomass, by finding ways to utilize lignin, previously treated as waste. Common pretreatment methods are unsustainable, prompting research into eco-friendly solvents and advanced techniques like ultrasound- and microwave-assisted methods. Recent approaches have also explored the use of eutectic solvents, which, when combined with these intensification techniques, offer promising results. These green technologies improve delignification efficiency, which in turn improves the saccharification process, reduces solvent use, and minimizes environmental impact. Despite progress, challenges remain in making these methods economically viable and adaptable to diverse biomass types. This review article highlights recent advances in sustainable treatment technologies, including the combined use of eutectic solvents and process-intensification techniques, and the potential of the obtained lignin in various industrial applications. It also discusses future prospects for more environmentally friendly processes in biomass utilization. Full article

(This article belongs to the Special Issue Novel Sustainable Processes with Low Environmental Impact Solvents in Biorefining and Chemical Industry)

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23 pages, 5031 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

The Electrooxidation of Synthetic Bipyridyl Herbicide Wastewaters with Boron-Doped Diamond Electrodes: A Technical and Economic Study to Boost Their Application for Pollution Prevention in the Agricultural Sector

by Elia Alejandra Teutli-Sequeira, Ruben Vasquez-Medrano, Dorian Prato-Garcia and Jorge G. Ibanez

Processes 2024, 12(11), 2486; https://doi.org/10.3390/pr12112486 - 8 Nov 2024

Cited by 1 | Viewed by 854

Abstract

Boron-doped diamond electrodes (BDDEs) offer a highly efficient pathway to mineralize recalcitrant compounds due to their reduced energy requirements, fewer chemical inputs, and mechanical stability. In this work, the electrochemical degradation of paraquat (PQ) and diquat (DQ) was studied using an undivided cell [...] Read more.

Boron-doped diamond electrodes (BDDEs) offer a highly efficient pathway to mineralize recalcitrant compounds due to their reduced energy requirements, fewer chemical inputs, and mechanical stability. In this work, the electrochemical degradation of paraquat (PQ) and diquat (DQ) was studied using an undivided cell (Condiacell^®-type) at circumneutral pH, and under galvanostatic control. The roles of applied current density, volumetric flow rate, and herbicide concentration were systematically studied through a central composite design (CCD) using a closed-flow reaction setup. Under the best operating conditions (i.e., for PQ: 1.6 mA/cm², 80 mL/min, and 70 mL/min, and 70 mg/L; and for DQ: 1.5 mA/cm², 80 mL/min, and 73 mg/L), a spectrophotometric analysis evidenced that the herbicides were satisfactorily removed (ca. 100%) while mineralization degrees were above 90%. Furthermore, the produced effluents yielded significant increases in seed germination and root length, which suggest a reduction in toxicity. Energy consumptions of 0.13 and 0.18 kWh/g of TOC are reported with the electrochemical cells for the PQ and DQ treatments, respectively. The PQ and DQ treatments by electrooxidation are estimated to emit nearly 2.7 and 38.9 kg CO₂/m³ of water treated, with a cost around USD 250/m³. Carbon emissions could be greatly decreased for PQ (0.28 kg CO₂/m³) and DQ (0.40 kg CO₂/m³) if electricity were generated from renewable resources. Although this study suggests that the use of BDDE can be considered as a green alternative for agrochemical removal due to lower carbon emissions, the environmental profile of the process is determined by the degree of renewability of the electrical grid of each country or region. Full article

(This article belongs to the Special Issue Advanced Oxidation Processes in Water Treatment)

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16 pages, 972 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Particle Size as an Indicator of Wheat Flour Quality: A Review

by Dariusz Dziki, Anna Krajewska and Pavol Findura

Processes 2024, 12(11), 2480; https://doi.org/10.3390/pr12112480 - 8 Nov 2024

Cited by 1 | Viewed by 3170

Abstract

Wheat flour is one of the most important food raw materials, with its quality determined by various indicators. One such indicator is particle size and granulometric distribution. In recent years, numerous studies have focused on the effect of flour and bran particle size [...] Read more.

Wheat flour is one of the most important food raw materials, with its quality determined by various indicators. One such indicator is particle size and granulometric distribution. In recent years, numerous studies have focused on the effect of flour and bran particle size on the properties of cereal products such as bread, pasta, noodles, and cookies. The aim of this review was to analyze the extent to which this parameter influences the properties of these cereal products. Additionally, the relationships between flour particle size and its chemical composition were presented. Key factors affecting the granulometric composition of flour, related to wheat grain properties and the grinding process, were also discussed. The study specifically focuses on research conducted in the last five years. Full article

(This article belongs to the Special Issue Feature Papers in the "Food Process Engineering" Section)

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15 pages, 6235 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Integrated Hybrid Modelling and Surrogate Model-Based Operation Optimization of Fluid Catalytic Cracking Process

by Haoran Li, Qiming Zhao, Ruqiang Wang, Wenle Xu and Tong Qiu

Processes 2024, 12(11), 2474; https://doi.org/10.3390/pr12112474 - 7 Nov 2024

Viewed by 1411

Abstract

Fluid Catalytic Cracking (FCC) is one of the most important conversion processes in oil refineries, widely used to convert high-boiling, high-molecular-weight hydrocarbon components from crude oil into more valuable products like gasoline and diesel. Advanced simulation and optimization technologies are critical for improving [...] Read more.

Fluid Catalytic Cracking (FCC) is one of the most important conversion processes in oil refineries, widely used to convert high-boiling, high-molecular-weight hydrocarbon components from crude oil into more valuable products like gasoline and diesel. Advanced simulation and optimization technologies are critical for improving the operational efficiency and economic performance of the FCC process. First-principles-based simulators rely on parameter estimation and are computationally intensive, making them unsuitable for online optimization. In recent years, with the development of deep learning, data-driven models have made significant progress in FCC modeling. However, due to their black-box nature and difficulty with extrapolation, they are rarely used for optimization. To bridge this gap, we propose an integrated framework that combines hybrid modeling and surrogate model-based optimization. This approach combines plant and simulation data to train a multi-task learning prediction model, which then serves as a surrogate for operational optimization. Validated on a large-scale FCC unit in southern China, the model predicts product yields with an error margin of under 4.84% for all products. Following optimization, yields of LNG, gasoline, and diesel rose by an average of 0.10 wt%, 1.58 wt%, and 1.05 wt%, respectively, resulting in a 3.67% increase in product revenues. This highlights the substantial potential of this framework for industrial applications. Full article

(This article belongs to the Special Issue Advances in Process Systems Engineering: Selected Papers from China PSE Annual Meeting)

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24 pages, 5010 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Accelerating Numerical Simulations of CO₂ Geological Storage in Deep Saline Aquifers via Machine-Learning-Driven Grid Block Classification

by Eirini Maria Kanakaki, Ismail Ismail and Vassilis Gaganis

Processes 2024, 12(11), 2447; https://doi.org/10.3390/pr12112447 - 5 Nov 2024

Viewed by 1445

Abstract

The accurate prediction of pressure and saturation distribution during the simulation of CO₂ injection into saline aquifers is essential for the successful implementation of carbon sequestration projects. Traditional numerical simulations, while reliable, are computationally expensive. Machine learning (ML) has emerged as a [...] Read more.

The accurate prediction of pressure and saturation distribution during the simulation of CO₂ injection into saline aquifers is essential for the successful implementation of carbon sequestration projects. Traditional numerical simulations, while reliable, are computationally expensive. Machine learning (ML) has emerged as a promising tool to accelerate these simulations; however, challenges remain in effectively capturing complex reservoir dynamics, particularly in regions experiencing rapid changes in pressure and saturation. This article addresses the challenges by introducing a fully automated, data-driven ML classifier that distinguishes between regions of fast and slow variation within the reservoir. Firstly, we demonstrate the variability in pressure across different reservoir grid blocks using a simple brine injection and production scenario, highlighting the limitations of conventional acceleration approaches. Subsequently, the proposed methodology leverages ML proxies to rapidly and accurately predict the behavior of slow-varying regions in CO₂ injection simulations, while traditional iterative methods are reserved for fast-varying areas. The results show that this hybrid approach significantly reduces the computational load without compromising on accuracy. This provides a more efficient and scalable solution for modeling CO₂ storage in saline aquifers. Full article

(This article belongs to the Special Issue Advanced Reservoir Simulation and Modelling, Thermal and Enhanced Oil Recovery Processes)

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19 pages, 3997 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

In Situ CALB Immobilization in Xerogel and Sonogel Employing TMOS as Silica Precursor and Polyethylene Glycol as Additive

by Angela Antunes, Carolina E. Demaman Oro, Andressa Franco Denti, Leonardo M. da Silva, Aline M. M. Ficanha, Jéssica Mulinari, Luciana D. Venquiaruto, Jamile Zeni, Marcelo L. Mignoni and Rogério M. Dallago

Processes 2024, 12(11), 2411; https://doi.org/10.3390/pr12112411 - 1 Nov 2024

Cited by 3 | Viewed by 1115

Abstract

The immobilization of enzymes, especially lipases, presents a significant challenge in contemporary biotechnology due to their wide-ranging application in industrial processes. Given the array of available techniques for enzyme immobilization, this study aimed to immobilize Candida antarctica B (CALB) lipase within silica xerogel [...] Read more.

The immobilization of enzymes, especially lipases, presents a significant challenge in contemporary biotechnology due to their wide-ranging application in industrial processes. Given the array of available techniques for enzyme immobilization, this study aimed to immobilize Candida antarctica B (CALB) lipase within silica xerogel and sonogel matrices obtained through the sol–gel technique. Polyethylene glycol (PEG) was incorporated as an additive, with tetramethylorthosilicate (TMOS) serving as the silica precursor. This study assessed the operational stability, storage stability, and thermal properties of the resulting supports. Results revealed that both sonogel and xerogel supports, supplemented with PEG, maintained storage stability above 50% throughout a 365-day period. Moreover, operational stability tests demonstrated that the xerogel support could be reused up to 21 times, while the sonogel support exhibited 10 reuses. Thermal analysis further highlighted a reduction in the deactivation constant and an elongation of the half-life time for both supports. These observations suggest that the supports effectively shield the enzyme from thermal inactivation. Overall, these findings underscore the potential utility of PEG-enhanced sonogel and xerogel supports in various industrial enzyme applications, providing valuable insights into their operational, storage, and thermal stability. Full article

(This article belongs to the Section Separation Processes)

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27 pages, 8454 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Comparative Techno-Economic Analysis of Parabolic Trough and Linear Fresnel Collectors with Evacuated and Non-Evacuated Receiver Tubes in Different Geographical Regions

by Mehdi Shokrnia, Mattia Cagnoli, Roberto Grena, Antonio D’Angelo, Michela Lanchi and Roberto Zanino

Processes 2024, 12(11), 2376; https://doi.org/10.3390/pr12112376 - 29 Oct 2024

Cited by 2 | Viewed by 1755

Abstract

In the context of Concentrated Solar Power (CSP) technology, this paper presents a comparison between the Parabolic Trough Collector (PTC) and the Linear Fresnel Collector (LFC), considering both evacuated and non-evacuated receiver tubes. The comparison was carried out in terms of the Levelized [...] Read more.

In the context of Concentrated Solar Power (CSP) technology, this paper presents a comparison between the Parabolic Trough Collector (PTC) and the Linear Fresnel Collector (LFC), considering both evacuated and non-evacuated receiver tubes. The comparison was carried out in terms of the Levelized Cost of Electricity (LCOE) considering a reference year and four locations in the world, characterized by different levels of direct normal irradiation (DNI) from 2183 kWh/m²/year to 3409 kWh/m²/year. The LCOE depends on economic parameters and on the net energy generated by a plant on an annual basis. The latter was determined by a steady-state 1D model that solved the energy balance along the receiver axis. This model required computing the incident solar power and heat losses. While the solar power was calculated by an optical ray-tracing model, heat losses were computed by a lumped-parameter model developed along the radial direction of the tube. Since the LFC adopted a secondary concentrator, no conventional correlation was applicable for the convective heat transfer from the glass cover to the environment. Therefore, a 2D steady-state CFD model was also developed to investigate this phenomenon. The results showed that the PTC could generate a higher net annual energy compared to the LFC due to a better optical performance ensured by the parabolic solar collector. Nevertheless, the difference between the PTC and the LFC was lower in the non-evacuated tubes because of lower heat losses from the LFC receiver tube. The economic analysis revealed that the PTC with the evacuated tube also achieved the lowest LCOE, since the higher cost with respect to both the LFC system and the non-evacuated PTC was compensated by the higher net energy yield. However, the non-evacuated LFC demonstrated a slightly lower LCOE compared to the non-evacuated PTC since the lower capital cost of the non-evacuated LFC outweighed its lower net annual energy yield. Finally, a sensitivity analysis was conducted to assess the impact on the LCOE of the annual optical efficiency and of the economic parameters. This study introduces key technical parameters in LFC technology requiring improvement to achieve the level of productivity of the PTC from a techno-economic viewpoint, and consequently, to fill the gap between the two technologies. Full article

(This article belongs to the Special Issue Heat and Mass Transfer Phenomena in Energy Systems)

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10 pages, 834 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Advanced Methods for Monitoring and Fault Diagnosis of Control Loops in Common Rail Systems

by Riccardo Bacci di Capaci and Gabriele Pannocchia

Processes 2024, 12(11), 2371; https://doi.org/10.3390/pr12112371 - 29 Oct 2024

Viewed by 1347

Abstract

Common rail systems are a key component of modern diesel engines and highly increase their performance. During their working lifetime, there could be critical damages or failures related to aging, like backlash or friction, or out-of-spec operating conditions, like low-quality fuel with, e.g., [...] Read more.

Common rail systems are a key component of modern diesel engines and highly increase their performance. During their working lifetime, there could be critical damages or failures related to aging, like backlash or friction, or out-of-spec operating conditions, like low-quality fuel with, e.g., the presence of water or particles or a high percentage of biodiesel. In this work, suitable data-driven methods are adopted to develop an automatic procedure to monitor, diagnose, and estimate some types of faults in common rail systems. In particular, the pressure control loop operating within the engine control unit is investigated; the system is described using a Hammerstein model composed of a nonlinear model for the control valve behavior and an extended linear model for the process dynamics, which also accounts for the presence of external disturbances. Three different sources of oscillations can be successfully detected and quantified: valve stiction, aggressive controller tuning, and external disturbance. Selected case studies are used to demonstrate the effectiveness of the developed methodology. Full article

(This article belongs to the Special Issue 10th Anniversary of Processes—Recent Advances in Process Control and Monitoring)

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23 pages, 4537 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Improvement of Properties of Bio-Oil from Biomass Pyrolysis in Auger Reactor Coupled to Fluidized Catalytic Bed Reactor

by Balkydia Campusano, Michael Jabbour, Lokmane Abdelouahed, Mélanie Mignot, Christine Devouge-Boyer and Bechara Taouk

Processes 2024, 12(11), 2368; https://doi.org/10.3390/pr12112368 - 28 Oct 2024

Viewed by 1547

Abstract

The goal of this research work was to investigate the improvement of bio-oil issued from beechwood biomass through catalytic de-oxygenation. Pyrolysis was conducted in an auger reactor and the catalytic treatment was performed in a fluidized catalytic bed reactor. Lab-synthesized Fe-HZSM-5 catalysts with [...] Read more.

The goal of this research work was to investigate the improvement of bio-oil issued from beechwood biomass through catalytic de-oxygenation. Pyrolysis was conducted in an auger reactor and the catalytic treatment was performed in a fluidized catalytic bed reactor. Lab-synthesized Fe-HZSM-5 catalysts with different iron concentrations were tested. BET specific surface area, BJH pore size distribution, and FT-IR technologies were used to characterize the catalysts. Thermogravimetric analysis was used to measure the amount of coke deposited on the catalysts after use. Gas chromatography coupled to mass spectrometry (GC-MS), flame ionization detection (GC-FID), and thermal conductivity detection (GC-TCD) were used to identify and quantify the liquid and gaseous products. The pyrolysis temperature proved to be the most influential factor on the final products. It was observed that a pyrolysis temperature of 500 °C, vapor residence time of 18 s, and solid residence time of 2 min resulted in a maximum bio-oil yield of 53 wt.%. A high percentage of oxygenated compounds, such as phenolic compounds, guaiacols, and the carboxylic acid group, was present in this bio-oil. Catalytic treatment with the Fe-HZSM-5 catalysts promoted gas production at the expense of the bio-oil yield, however, the composition of the bio-oil was strongly modified. These properties of the treated bio-oil changed as a function of the Fe loading on the catalyst, with 5%Fe-HZSM-5 giving the best performance. A higher iron loading of 5%Fe-HZSM-5 could have a negative impact on the catalyst performance due to increased coke formation. Full article

(This article belongs to the Special Issue Advances in Zeolite Catalytic Processes: Current Trends and Challenges in Processing Nonconventional Feedstocks)

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12 pages, 2367 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Optimization of Steaming Conditions for Bellflower Root (Platycodon grandiflorus) Using K-Means Clustering-Based Morphological Grading System

by Timilehin Martins Oyinloye, Seohee An, Chang-Won Cho and Won Byong Yoon

Processes 2024, 12(11), 2347; https://doi.org/10.3390/pr12112347 - 25 Oct 2024

Cited by 1 | Viewed by 762

Abstract

Bellflower roots were categorized into three clusters (class 0, class 1, and class 2) using K-means clustering based on their morphological factors: length (282.8 ± 29.53, 138.75 ± 26.8, and 209.89 ± 20.49 mm), thickness (16.25 ± 2.82, 16.77 ± 3.35, and 16.52 [...] Read more.

Bellflower roots were categorized into three clusters (class 0, class 1, and class 2) using K-means clustering based on their morphological factors: length (282.8 ± 29.53, 138.75 ± 26.8, and 209.89 ± 20.49 mm), thickness (16.25 ± 2.82, 16.77 ± 3.35, and 16.52 ± 3.05 mm), and body shape coefficient (5.80 ± 1.15, 12.73 ± 4.82, and 7.95 ± 1.71). Internal void formation, a key quality factor for bellflower root, was analyzed under pre-steaming conditions, identifying temperatures between 20 and 25 °C as optimal for storage. Within the clustered class, steaming for a prolonged duration increased the formation of internal voids and caused a decrease in normal stress values, total dissolved solids (TDS), and pectin content. Class 0, with larger and thicker roots, exhibited higher internal voids (57% void rate) due to uneven heat distribution and incomplete starch gelatinization. Class 2 roots demonstrated better structural integrity, with a void rate of 26% and a stress value of 48 kN/m². These findings highlight the importance of morphological classification and optimal storage temperatures to improve the quality of steamed bellflower roots. Full article

(This article belongs to the Special Issue Drying Kinetics and Quality Control in Food Processing, 2nd Edition)

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36 pages, 7626 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Evaluating Benchtop Additive Manufacturing Processes Considering Latest Enhancements in Operational Factors

by Antreas Kantaros, Florian Ion Tiberiu Petrescu, Konstantinos Brachos, Theodore Ganetsos and Nicolae Petrescu

Processes 2024, 12(11), 2334; https://doi.org/10.3390/pr12112334 - 24 Oct 2024

Cited by 12 | Viewed by 1616

Abstract

With the evolution of additive manufacturing technologies, concerning their material processing techniques, range of material choices and deposition speed, 3D printers are extensively employed in academia and industry for a number of purposes. It is no longer uncommon to have a portable, desktop [...] Read more.

With the evolution of additive manufacturing technologies, concerning their material processing techniques, range of material choices and deposition speed, 3D printers are extensively employed in academia and industry for a number of purposes. It is no longer uncommon to have a portable, desktop 3D printer and build specific designs in a matter of minutes or hours. The functionality, costs, materials and applications of desktop 3D printers differ. Among the several desktop 3D printers with a variety of characteristics, it might be challenging to choose which one is optimal for the intended applications and uses. In this study, a variety of commercially available thermoplastic and photopolymer resin desktop 3D printers are presented and compared for user selection. This article intends to provide end-users of desktop 3D printers with fundamental information and guidelines via a comparison of desktop 3D-printing technologies and their technical characteristics, enabling them to assess and select appropriate desktop 3D printers for a variety of applications. Full article

(This article belongs to the Special Issue AI-Supported Methods and Process Modeling in Smart Manufacturing)

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18 pages, 4662 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Electrospun Fibers of Ecovio^® Polymer Blends with Antimicrobial Tea Tree Essential Oil: Enhanced Chemical and Biological Properties

by Bianca Z. de Souza, Débora P. Facchi, Suelen P. Facchi, Carlos F. Teodoro, Débora A. de Almeida, Ketul C. Popat, Matt J. Kipper, Elton G. Bonafé and Alessandro F. Martins

Processes 2024, 12(11), 2330; https://doi.org/10.3390/pr12112330 - 24 Oct 2024

Cited by 1 | Viewed by 1069

Abstract

This study presents the development of fibers with favorable properties for biodegradable wound dressings made from the Ecovio^® (EC) polymer blend, composed of poly(lactic acid) (PLA) and poly(butylene adipate-co-terephthalate) (PBAT), incorporated with tea tree essential oil (TTE). TTE presented antimicrobial activity against [...] Read more.

This study presents the development of fibers with favorable properties for biodegradable wound dressings made from the Ecovio^® (EC) polymer blend, composed of poly(lactic acid) (PLA) and poly(butylene adipate-co-terephthalate) (PBAT), incorporated with tea tree essential oil (TTE). TTE presented antimicrobial activity against Pseudomonas aeruginosa and Staphylococcus aureus, achieving minimal inhibitory concentrations (MIC) of 15 and 7.5 mg/mL, respectively. The TTE was mixed with EC in a binary chloroform and formic acid (85/15 v/v) mixture. The EC/TTE fibers were characterized by differential scanning calorimetry (DSC), Fourier-transform infrared with attenuated total reflectance (FTIR-ATR), and X-ray photoelectron spectroscopy (XPS), confirming the TTE in the fibers. The tests showed that TTE (0.5, 1.0, or 1.5 mL) improved the polymer blend’s electrospinnability, leading to bead-free, homogenous, and smaller fiber diameters. TTE (1.5 mL or 75 w% concerning the EC) leads to homogeneous fibers with an average diameter of 278 ± 59 nm. TTE (75 w%) increased the wettability of the EC fibers from 120 ± 2° to 69 ± 1°. Preliminary bacterial adhesion and proliferation assays demonstrated that the EC/TTE fibers have anti-adhesive activity and demonstrate greater toxicity, which seems more toxic against P. aeruginosa than S. aureus after 24 h of incubation. Fluorescence and coagulation kinetics tests performed with human blood indicated that the EC/TTE fibers accelerate blood coagulation. The EC/TTE fibers exhibit promising chemical and biological properties (in vitro) for developing wound dressings. Full article

(This article belongs to the Special Issue Antimicrobials in Plants: From Traditional Medicine to Modern Therapeutic Agents)

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21 pages, 4547 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Electric Vehicle Thermal System Concept Development for Multiple Variants Using Digital Prototype and AI

by Muhammad Bilal, Simon Petrovich and Kambiz Ebrahimi

Processes 2024, 12(11), 2314; https://doi.org/10.3390/pr12112314 - 22 Oct 2024

Viewed by 1629

Abstract

The automotive industry is experiencing a surge in system complexity driven by the ever-growing number of interacting components, subsystems, and control systems. This complexity is further amplified by the expanding range of component options available to original equipment manufacturers (OEMs). OEMs work in [...] Read more.

The automotive industry is experiencing a surge in system complexity driven by the ever-growing number of interacting components, subsystems, and control systems. This complexity is further amplified by the expanding range of component options available to original equipment manufacturers (OEMs). OEMs work in parallel on more than one vehicle model, with multiple vehicle variants for each vehicle model. With the increasing number of vehicle variants needed to cater to diverse regional needs, development complexity escalates. To address this challenge, modern techniques like Model-Based Systems Engineering (MBSE), digitalization, and Artificial Intelligence (AI) are becoming essential tools. These advancements can streamline concept development, optimize thermal and HVAC system design across variants, and accelerate the time-to-market for next-generation EVs. The development of battery electric vehicles (BEVs) needs a strong focus on thermal management systems (TMSs) and heating, ventilation, and air conditioning (HVAC) systems. These systems play a critical role in maintaining optimal battery temperature, maximizing range and efficiency, and ensuring passenger comfort. This article proposes a digital prototype (DP) and AI-based methodology to specify BEV thermal system and HVAC system components in the concept phase. This methodology uses system and variant thinking in combination with digital prototype (DP) and AI to verify BEV thermal system architecture component specifications for future variants without extensive simulation. A BEV cabin cooling requirement of 22 °C to be achieved within 1800s at a high ambient temperature (45 °C) is required, and its verification is used to prove this methodology. Full article

(This article belongs to the Special Issue Energy Storage Systems and Thermal Management)

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18 pages, 3810 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Continuous Biological Ex Situ Methanation of CO₂ and H₂ in a Novel Inverse Membrane Reactor (IMR)

by Fabian Haitz, Oliver Jochum, Agnieszka Lasota, André Friedrich, Markus Bieri, Marc Stalder, Martin Schaub, Ulrich Hochberg and Christiane Zell

Processes 2024, 12(10), 2305; https://doi.org/10.3390/pr12102305 - 21 Oct 2024

Viewed by 1641

Abstract

A promising approach for carbon dioxide (CO₂) valorization and storing excess electricity is the biological methanation of hydrogen and carbon dioxide to methane. The primary challenge here is to supply sufficient quantities of dissolved hydrogen. The newly developed Inverse Membrane Reactor [...] Read more.

A promising approach for carbon dioxide (CO₂) valorization and storing excess electricity is the biological methanation of hydrogen and carbon dioxide to methane. The primary challenge here is to supply sufficient quantities of dissolved hydrogen. The newly developed Inverse Membrane Reactor (IMR) allows for the spatial separation of the required reactant gases, hydrogen (H₂) and carbon dioxide (CO₂), and the degassing area for methane (CH₄) output through commercially available ultrafiltration membranes, enabling a reactor design as a closed circuit for continuous methane production. In addition, the Inverse Membrane Reactor (IMR) facilitates the utilization of hydraulic pressure to enhance hydrogen (H₂) input. One of the process’s advantages is the potential to utilize both carbon dioxide (CO₂) from conventional biogas and CO₂-rich industrial waste gas streams. An outstanding result from investigating the IMR revealed that, employing the membrane gassing concept, methane concentrations of over 90 vol.% could be consistently achieved through flexible gas input over a one-year test series. Following startup, only three supplemental nutrient additions were required in addition to hydrogen (H₂) and carbon dioxide (CO₂), which served as energy and carbon sources, respectively. The maximum achieved methane formation rate specific to membrane area was 87.7 L_N of methane per m² of membrane area per day at a product gas composition of 94 vol.% methane, 2 vol.% H₂, and 4 vol.% CO₂. Full article

(This article belongs to the Special Issue Innovations in Gaseous, Liquid and Solid Products during Biogas Generation and Utilization)

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27 pages, 3503 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Thermodynamic Model-Based Synthesis of Heat-Integrated Work Exchanger Networks

by Aida Amini-Rankouhi, Abdurrafay Siddiqui and Yinlun Huang

Processes 2024, 12(10), 2293; https://doi.org/10.3390/pr12102293 - 19 Oct 2024

Viewed by 987

Abstract

Heat integration has been widely and successfully practiced for recovering thermal energy in process plants for decades. It is usually implemented through synthesizing heat exchanger networks (HENs). It is recognized that mechanical energy, another form of energy that involves pressure-driven transport of compressible [...] Read more.

Heat integration has been widely and successfully practiced for recovering thermal energy in process plants for decades. It is usually implemented through synthesizing heat exchanger networks (HENs). It is recognized that mechanical energy, another form of energy that involves pressure-driven transport of compressible fluids, can be recovered through synthesizing work exchanger networks (WENs). One type of WEN employs piston-type work exchangers, which demonstrates techno-economic attractiveness. A thermodynamic-model-based energy recovery targeting method was developed to predict the maximum amount of mechanical energy feasibly recoverable by piston-type work exchangers prior to WEN configuration generation. In this work, a heat-integrated WEN synthesis methodology embedded by the thermodynamic model is introduced, by which the maximum mechanical energy, together with thermal energy, can be cost-effectively recovered. The methodology is systematic and general, and its efficacy is demonstrated through two case studies that highlight how the proposed methodology leads to designs simpler than those reported by other researchers while also having a lower total annualized cost (TAC). Full article

(This article belongs to the Special Issue Industrial IoT-Enabled Modeling and Optimization for the Process Industry)

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33 pages, 3665 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Role of Sintering Aids in Electrical and Material Properties of Yttrium- and Cerium-Doped Barium Zirconate Electrolytes

by Shivesh Loganathan, Saheli Biswas, Gurpreet Kaur and Sarbjit Giddey

Processes 2024, 12(10), 2278; https://doi.org/10.3390/pr12102278 - 18 Oct 2024

Cited by 2 | Viewed by 1778

Abstract

Ceramic proton conductors have the potential to lower the operating temperature of solid oxide cells (SOCs) to the intermediate temperature range of 400–600 °C. This is attributed to their superior ionic conductivity compared to oxide ion conductors under these conditions. However, prominent proton-conducting [...] Read more.

Ceramic proton conductors have the potential to lower the operating temperature of solid oxide cells (SOCs) to the intermediate temperature range of 400–600 °C. This is attributed to their superior ionic conductivity compared to oxide ion conductors under these conditions. However, prominent proton-conducting materials, such as yttrium-doped barium cerates and zirconates with specified compositions like BaCe_1−xY_xO_3−δ (BCY), BaZr_1−xY_xO_3−δ (BZY), and Ba(Ce,Zr)_1−yY_yO_3−δ (BCZY), face significant challenges in achieving dense electrolyte membranes. It is suggested that the incorporation of transition and alkali metal oxides as sintering additives can induce liquid phase sintering (LPS), offering an efficient method to facilitate the densification of these proton-conducting ceramics. However, current research underscores that incorporating these sintering additives may lead to adverse secondary effects on the ionic transport properties of these materials since the concentration and mobility of protonic defects in a perovskite are highly sensitive to symmetry change. Such a drop in ionic conductivity, specifically proton transference, can adversely affect the overall performance of cells. The extent of variation in the proton conductivity of the perovskite BCZY depends on the type and concentration of the sintering aid, the nature of the sintering aid precursors used, the incorporation technique, and the sintering profile. This review provides a synopsis of various potential sintering techniques, explores the influence of diverse sintering additives, and evaluates their effects on the densification, ionic transport, and electrochemical properties of BCZY. We also report the performance of most of these combinations in an actual test environment (fuel cell or electrolysis mode) and comparison with BCZY. Full article

(This article belongs to the Section Chemical Processes and Systems)

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14 pages, 1214 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Phytochemical Extract from Syzygium cumini Leaf: Maximization of Compound Extraction, Chemical Characterization, Antidiabetic and Antibacterial Activity, and Cell Viability

by Ana Claudia Santos da Rosa, Jaqueline Hoscheid, Vitor Augusto dos Santos Garcia, Oscar de Oliveira Santos Junior and Camila da Silva

Processes 2024, 12(10), 2270; https://doi.org/10.3390/pr12102270 - 17 Oct 2024

Cited by 2 | Viewed by 1917

Abstract

This work aimed to obtain a phytochemical extract from jambolan leaf using a hydroethanolic solvent and ultrasound-assisted extraction. For this purpose, an experimental design was applied to analyze the effect of process variables related to temperature (30–60 °C), time (10–30 min), and solvent [...] Read more.

This work aimed to obtain a phytochemical extract from jambolan leaf using a hydroethanolic solvent and ultrasound-assisted extraction. For this purpose, an experimental design was applied to analyze the effect of process variables related to temperature (30–60 °C), time (10–30 min), and solvent to leaf ratio (5–15 mL g⁻¹), on the extraction mass yield (EMY) and on the yield of phenolic compounds (PCY). The effect of extractor solvent, AE (absolute ethanol), 75E (75% v·v⁻¹ ethanol) and 50E (50% v·v⁻¹), on the chemical characterization of the extracts, antidiabetic and antimicrobial activity, and cell viability, were also evaluated. The application of the highest values of process variables resulted in obtaining the maximum of the response variables (EMY = 9.94 wt% and PCY = 13.01 mg GAE g⁻¹ leaf). A higher content of phenolic compounds and flavonoids was obtained with 50E, which is mainly composed of sinapic, vanillic, trans-caffeic, and quinic acids, which were responsible for the greatest antioxidant potential, antibacterial activity (against Staphylococcus aureus and Pseudomonas aeruginosa), and inhibition of α-amylase. On the other hand, the use of AE allowed us to obtain extracts with higher concentrations of squalene, α-tocopherol, β-sitosterol, and friedelin. From cell viability tests, the extracts are not considered toxic at the concentration tested (100 µg mg⁻¹). Full article

(This article belongs to the Special Issue Trends in Extraction and Detection of Phenolic Compounds and Their Application)

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28 pages, 2694 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Critical Review of Lithium Recovery Methods: Advancements, Challenges, and Future Directions

by Subin Antony Jose, Jonathan Luke Stoll, Tyson Smith, Chase Jackson, Trent Dieleman, Easton Leath, Nicholas Eastwood and Pradeep L. Menezes

Processes 2024, 12(10), 2203; https://doi.org/10.3390/pr12102203 - 10 Oct 2024

Cited by 11 | Viewed by 6878

Abstract

The integration of lithium into technological applications has profoundly influenced human development, particularly in energy storage systems like lithium-ion batteries. With global demand for lithium surging alongside technological advancements, the sustainable extraction and recovery of this critical material have become increasingly vital. This [...] Read more.

The integration of lithium into technological applications has profoundly influenced human development, particularly in energy storage systems like lithium-ion batteries. With global demand for lithium surging alongside technological advancements, the sustainable extraction and recovery of this critical material have become increasingly vital. This paper explores lithium’s role, its chemical properties, and the environmental and economic considerations associated with its extraction and recovery. We examine various lithium recovery methods, including conventional techniques such as hydrometallurgy, pyrometallurgy, and direct physical recycling, as well as emerging technologies like mechanochemistry, ion pumping, and bioleaching while emphasizing the need for sustainable practices to address environmental challenges. The review also discusses the challenges and future directions of lithium recovery. Advances in technology have streamlined lithium recovery processes and spurred the development of innovative extraction techniques. This paper concludes with an emphasis on further research essential to deepen our understanding of lithium recovery methods, their strengths and limitations, and the need to explore new strategies to meet the growing global demand for this indispensable resource. Full article

(This article belongs to the Special Issue Circular Economy and Efficient Use of Resources (Volume II))

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25 pages, 2698 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Modelling Approach for the Continuous Biocatalytic Synthesis of N-Acetylneuraminic Acid in Packed Bed Reactors

by Kristin Hölting, Miriam Aßmann, Paul Bubenheim, Andreas Liese and Jürgen Kuballa

Processes 2024, 12(10), 2191; https://doi.org/10.3390/pr12102191 - 9 Oct 2024

Viewed by 1593

Abstract

Continuous flow technologies have become increasingly important for biocatalytic processes. In this study, we present the application and modelling of covalently immobilised N-acetylglucosamine 2-epimerase and N-acetylneuraminic acid lyase in packed bed reactors for the synthesis of N-acetylneuraminic acid. The immobilised [...] Read more.

Continuous flow technologies have become increasingly important for biocatalytic processes. In this study, we present the application and modelling of covalently immobilised N-acetylglucosamine 2-epimerase and N-acetylneuraminic acid lyase in packed bed reactors for the synthesis of N-acetylneuraminic acid. The immobilised enzymes were stable under continuous flow process conditions with half-life times of >28 d (epimerase immobilised on hexamethylamino methacrylate HA403/M) or 58 d (lyase immobilised on dimenthylamino methacrylate ECR8309M), suitable for continuous flow applications. Kinetic studies revealed Michaelis–Menten kinetic behaviour for both enzymes. The kinetic parameters and the inhibitions were analysed under continuous flow conditions and were integrated into a process model using Python. The model was validated by varying flow rates, the mass of immobilised enzymes and the reactor dimensions and shows a low error compared to the measured data. An error accuracy of 6% (epimerase) or 9% (lyase) was achieved. The product concentrations of the enzyme cascade at the end of the packed bed reactor can be predicted with an accuracy of 9% for the calculation of a large column (84.5 mL) or of 24% if several small columns (2.5 mL, 0.8 mL) are connected in series. The developed model has proved to be valid and will be used to optimise the process with respect to substrate concentrations, reactor dimensions and flow rate. Full article

(This article belongs to the Special Issue Development, Modelling and Simulation of Biocatalytic Processes)

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16 pages, 5727 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Three-Dimensional Morphological Study of MnTe-like Structures by Assessment of Tortuosity Tensor Using Computational Fluid Dynamics

by Giuseppe Prenesti, Edoardo Walter Petrassi, Caterina Guzzo, Silvia Mannella, Francesco Stellato, Laura Crisafulli, Giulia Azzato, Andrea Katovic, Agostino Lauria and Alessio Caravella

Processes 2024, 12(10), 2175; https://doi.org/10.3390/pr12102175 - 7 Oct 2024

Viewed by 1332

Abstract

This paper focuses on a morphological study of the MnTe-like structures, carried out by the evaluation of the tortuosity tensor and other related parameters using a computational fluid dynamics approach recently developed by our research group. The present work focuses on all possible [...] Read more.

This paper focuses on a morphological study of the MnTe-like structures, carried out by the evaluation of the tortuosity tensor and other related parameters using a computational fluid dynamics approach recently developed by our research group. The present work focuses on all possible crystals—existing or not developed yet—having the same structure as that of the manganese telluride. This analysis provides new information not present yet in the open literature. The motivation behind this study lies in the importance of this type of structure in physics and material science. In particular, the structures investigated are anisotropic and bi-disperse, with two independent geometrical parameters controlling the structure shape: the ratio of the particle diameters (r₁) and the normalised inter-particle distance (r₂). Exploiting this fact, several different structures of the same family are created, changing these two parameters independently, also allowing inter-penetration of particles to enlarge the study’s applicability. The results are primarily obtained in terms of the tortuosity tensor, needed to catch and quantify the anisotropy of the structures. Then, other morphological parameters, such as connectivity, principal diffusion directions, and anisotropy factors, are evaluated, obtaining in this way a novel morphological characterisation of the structure. It is found that high values of tortuosity are observed at lower and higher values of {r₁, r₂}, which means that there exists a minimum value between them. Additionally, the anisotropy factor is found to be higher at lower values of {r₁, r₂} and lower at higher ones. This is in accordance with the fact that, as the inter-particle distance and the ratio between particle diameters increase, the structure enlarges, which implies a lower influence of the particle distribution and, thus, a gradually more isotropic structure. Full article

(This article belongs to the Special Issue 10th Anniversary of Processes: Design of the Chemical Industry of the Future)

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24 pages, 4071 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Analysis of Aromatic Fraction of Sparkling Wine Manufactured by Second Fermentation and Aging in Bottles Using Different Types of Closures

by Patricia Jové, Glòria Mateu-Figueras, Jessica Bustillos and Josep Antoni Martín-Fernández

Processes 2024, 12(10), 2165; https://doi.org/10.3390/pr12102165 - 4 Oct 2024

Viewed by 1357

Abstract

This study aimed to evaluate the impact of different closures used in second fermentation on the aromatic fraction of sparkling wine. Six types of closures (cork stoppers and screw caps) and 94 months of aging in a bottle were investigated. Headspace solid-phase microextraction [...] Read more.

This study aimed to evaluate the impact of different closures used in second fermentation on the aromatic fraction of sparkling wine. Six types of closures (cork stoppers and screw caps) and 94 months of aging in a bottle were investigated. Headspace solid-phase microextraction (HS-SPME) and thermal desorption (TD) procedures coupled to gas chromatography-mass spectrometry (GCMSMS) analysis were applied. The vectors containing the relative abundance of the volatile compounds are compositional vectors. The statistical analysis of compositional data requires specific techniques that differ from standard techniques. Overall, 101 volatile compounds were identified. HS-SPME extracted the highest percentage of esters, ketones and other compounds, while TD was a useful tool for the obtention of alcohol, acid, ether and alkane compounds. Esters were the most abundant family of compounds. Compositional data analysis, which was applied to study the impact of different closures used in bottle aging after second fermentation on the volatile composition of sparkling wine, concluded that there are differences in the relative abundance of certain volatile compounds between cork stoppers and screw-cap closures. Overall, the most abundant part in screw-cap closures was ethyl hexanoate, and it was ethyl octanoate in cork stoppers. Also, the proportional amount of dimethylamine was higher in screw-cap closures than cork stoppers relative to the entire sample. Full article

(This article belongs to the Special Issue Applications of Chromatographic Separation Techniques in Food and Chemistry—Second Edition)

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15 pages, 1881 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Kombucha Fermentation in Coffee: Application of Constant Air Flow Reactor

by Błażej Błaszak, Piotr Dorawa, Paweł Sudoł, Karolina Fabiszak, Martyna Świadek, Klaudia Witucka, Julia Zimnicka, Mateusz Brudnicki, Bartosz Maciejewski, Daniil Bovkun, Marek Cierach, Grażyna Gozdecka and Joanna Szulc

Processes 2024, 12(10), 2159; https://doi.org/10.3390/pr12102159 - 3 Oct 2024

Cited by 1 | Viewed by 1935

Abstract

SCOBY (symbiotic culture of bacteria and yeasts) is an artificially created mixed culture containing selected strains of acetic acid and lactic acid bacteria and yeast which are present in the cellulose membrane. The growing popularity of kombucha consumption and high popularity of coffee [...] Read more.

SCOBY (symbiotic culture of bacteria and yeasts) is an artificially created mixed culture containing selected strains of acetic acid and lactic acid bacteria and yeast which are present in the cellulose membrane. The growing popularity of kombucha consumption and high popularity of coffee creates the possibility of developing coffee-based kombucha production on an industrial scale, which currently does not differ in method from production on a laboratory scale and at home. Therefore, the aim of this work was to determine the possibility of using an alternative method of coffee fermentation using SCOBY, in which the fermentation was carried out in a bioreactor with a constant air flow (rate 2L/min). This study determined the effect of the fermentation method on the processing time, SCOBY mass gain, and selected properties of the fermented coffee beverage. The alternative fermentation method did not negatively affect the properties of the fermented coffee beverage, i.e., caffeine content, colour, polyphenol content, and antioxidant properties, in comparison with the traditional fermentation method. Additionally, it accelerated the fermentation process, shortening it from 8 to 4 days, and in some cases caused an increase in the total polyphenol content and antioxidant activity, almost 10% and over 40%, respectively. The results of this study show a possibility to use alternative methods for coffee fermentation, which can be easily adapted for industrial scale. Variants of fermented and aerated beverages with 4% coffee, and 4 and 5% sugar concentrations stood out among the others as having the best properties and might be introduced to the industry. Full article

(This article belongs to the Special Issue Microbiotechnology in Cosmetics, Pharmaceuticals and Food)

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12 pages, 5741 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Study of Helium Irradiation Effect on Al6061 Alloy Fabricated by Additive Friction Stir Deposition

by Uttam Bhandari, Huan Ding, Congyuan Zeng, Shizhong Yang, Abdennaceur Karoui, Hyosim Kim, Pengcheng Zhu, Matthew Ryan Chancey, Yongqiang Wang and Shengmin Guo

Processes 2024, 12(10), 2144; https://doi.org/10.3390/pr12102144 - 2 Oct 2024

Viewed by 1053

Abstract

Additive friction stir deposition (AFS-D) is considered a productive method of additive manufacturing (AM) due to its ability to produce dense mechanical parts at a faster deposition rate compared to other AM methods. Al6061 alloy finds extensive application in aerospace and nuclear engineering; [...] Read more.

Additive friction stir deposition (AFS-D) is considered a productive method of additive manufacturing (AM) due to its ability to produce dense mechanical parts at a faster deposition rate compared to other AM methods. Al6061 alloy finds extensive application in aerospace and nuclear engineering; nevertheless, exposure to radiation or high-energy particles over time tends to deteriorate their mechanical performance. However, the effect of radiation on the components manufactured using the AFS-D method is still unexamined. In this work, samples from the as-fabricated Al6061 alloy, by AFS-D, and the Al6061 feedstock rod were irradiated with He+ ions to 10 dpa at ambient temperature. The microstructural and mechanical changes induced by irradiation of He+ were examined using a scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), and nanoindentation. This study demonstrates that, at 10 dpa of irradiation damage, the feedstock Al6061 produced a bigger size of He bubbles than the AFS-D Al6061. Nanoindentation analysis revealed that both the feedstock Al6061 and AFS-D Al6061 samples have experienced radiation-induced hardening. These studies provide a valuable understanding of the microstructural and mechanical performance of AFS-D materials in radiation environments, offering essential data for the selection of materials and processing methods for potential application in aerospace and nuclear engineering. Full article

(This article belongs to the Special Issue Composite Materials Processing, Modeling and Simulation)

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10 pages, 260 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Experimental Application of Beneficial, Freeze-Dried Strain Enterococcus durans ED 26E/7 with Postbiotic Activity in Different Yogurts, Its Survival and Stability

by Andrea Lauková, Emília Dvorožňáková, Miroslava Petrová, Marcela Maloveská, Eva Bino, Natália Zábolyová, Anna Kandričáková and Monika Pogány Simonová

Processes 2024, 12(10), 2138; https://doi.org/10.3390/pr12102138 - 1 Oct 2024

Viewed by 827

Abstract

Yogurt is generally defined as a cultured milk product made using some species of lactic acid bacteria. Moreover, some additive bacteria are frequently involved in yogurts to provide health benefits. The objective of this study was testing the stability and survival of a [...] Read more.

Yogurt is generally defined as a cultured milk product made using some species of lactic acid bacteria. Moreover, some additive bacteria are frequently involved in yogurts to provide health benefits. The objective of this study was testing the stability and survival of a beneficial strain with postbiotic activity, Enterococcus durans ED 26E/7, in cow, goat, and ewe–goat milk yogurts. The validated methods were used in the study. Postbiotic, concentrated substance (CBs) from the strain ED 26E/7 inhibited growth of indicator bacteria by 60.5%. The strains E. hirae (96%) were susceptible to CBs (inhibitory activity from 200 to 25,600 AU/mL). The growth of staphylococci was inhibited by 79% with activity of 100 up to 25,600 AU/mL. Also, 40 out of 46 fecal E. coli were inhibited (activity 100 AU/mL). CBs was thermo-stable and remained active also after storage for 11 months at −20 °C and −80 °C. Exposing CBs to proteolytic enzymes did not lead to its complete deactivation indicating that it is probably not only a proteinaceous substance. The highest counts of the freeze-dried (encapsulated), safe ED 26E/7 strain and its stability were detected in ewe–goat milk yogurts. They reached up to 5.0 cfu/g. ED 26E/7 represents a further promising additive, although other testing will be performed. Full article

(This article belongs to the Section Food Process Engineering)

27 pages, 2494 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Physical Cell Disruption Technologies for Intracellular Compound Extraction from Microorganisms

by Fujunzhu Zhao, Zhiwu Wang and Haibo Huang

Processes 2024, 12(10), 2059; https://doi.org/10.3390/pr12102059 - 24 Sep 2024

Cited by 7 | Viewed by 5484

Abstract

This review focuses on the physical disruption techniques in extracting intracellular compounds, a critical step that significantly impacts yield and purity. Traditional chemical extraction methods, though long-established, face challenges related to cost and environmental sustainability. In response to these limitations, this paper highlights [...] Read more.

This review focuses on the physical disruption techniques in extracting intracellular compounds, a critical step that significantly impacts yield and purity. Traditional chemical extraction methods, though long-established, face challenges related to cost and environmental sustainability. In response to these limitations, this paper highlights the growing shift towards physical disruption methods—high-pressure homogenization, ultrasonication, milling, and pulsed electric fields—as promising alternatives. These methods are applicable across various cell types, including bacteria, yeast, and algae. Physical disruption techniques achieve relatively high yields without degrading the bioactivity of the compounds. These techniques, utilizing physical forces to break cell membranes, offer promising extraction efficiency, with reduced environmental impacts, making them attractive options for sustainable and effective intracellular compound extraction. High-pressure homogenization is particularly effective for large-scale extracting of bioactive compounds from cultivated microbial cells. Ultrasonication is well-suited for small to medium-scale applications, especially for extracting heat-sensitive compounds. Milling is advantageous for tough-walled cells, while pulsed electric field offers gentle, non-thermal, and highly selective extraction. This review compares the advantages and limitations of each method, emphasizing its potential for recovering various intracellular compounds. Additionally, it identifies key research challenges that need to be addressed to advance the field of physical extractions. Full article

(This article belongs to the Special Issue Fermentation and Bioprocess Engineering Processes)

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20 pages, 3285 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Optimization of Recovery of Nutrients from Pig Manure Slurry through Combined Microbial Fuel Cell and Microalgae Treatment

by Adrián Hernández-Fernández, Eduardo Iniesta-López, Ana Isabel Hernández Baños, Yolanda Garrido, Ana Sánchez Zurano, Francisco J. Hernández-Fernández and Antonia Pérez De los Ríos

Processes 2024, 12(9), 1989; https://doi.org/10.3390/pr12091989 - 15 Sep 2024

Cited by 1 | Viewed by 2074

Abstract

Microbial fuel cells (MFCs) and microalgae–bacteria consortia represent two renewable and promising technologies of growing interest that enable wastewater treatment while obtaining high-value-added products. This study integrates MFCs and microalgae production systems to treat animal slurry, aiming to remove and recover organic and [...] Read more.

Microbial fuel cells (MFCs) and microalgae–bacteria consortia represent two renewable and promising technologies of growing interest that enable wastewater treatment while obtaining high-value-added products. This study integrates MFCs and microalgae production systems to treat animal slurry, aiming to remove and recover organic and inorganic components while generating energy and producing biomass. The MFCs effectively eliminated Chemical Oxygen Demand (COD), organic nitrogen, and a portion of the suspended solids, achieving a maximum voltage of 195 mV and a power density of 87.03 mW·m⁻². After pre-treatment with MFCs, the slurry was diluted to concentrations of 10%, 50%, and 100% and treated with microalgae–bacteria consortia. The results showed a biomass production of 0.51 g·L⁻¹ and a productivity of 0.04 g·L⁻¹·day⁻¹ in the culture fed with 10% slurry, with significant removal efficiencies: 40.71% for COD, 97.76% for N-NH₄₊, 39.66% for N-NO₂⁻, 47.37% for N-NO₃⁻, and 94.37% for P-PO₄⁻³. The combination of both technologies allowed for obtaining a properly purified slurry and the recovery of nutrients in the form of bioelectricity and high-value biomass. Increasing the concentration of animal slurry to be treated is essential to optimize and scale both technologies. Full article

(This article belongs to the Special Issue Biochemical Processes for Sustainability, 2nd Edition)

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25 pages, 1113 KiB

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Semi-Analytical Closed-Form Solutions of the Ball–Plate Problem

by Remus-Daniel Ene and Nicolina Pop

Processes 2024, 12(9), 1977; https://doi.org/10.3390/pr12091977 - 13 Sep 2024

Viewed by 819

Abstract

Mathematical models and numerical simulations are necessary to understand the dynamical behaviors of complex systems. The aim of this work is to investigate closed-form solutions for the ball–plate problem considering a system derived from an optimal control problem for ball–plate dynamics. The nonlinear [...] Read more.

Mathematical models and numerical simulations are necessary to understand the dynamical behaviors of complex systems. The aim of this work is to investigate closed-form solutions for the ball–plate problem considering a system derived from an optimal control problem for ball–plate dynamics. The nonlinear properties of ball and plate control system are presented in this work. To semi-analytically solve this system, we explored a second-order nonlinear differential equation. Consequently, we obtained the approximate closed-form solutions by the Optimal Parametric Iteration Method (OPIM) using only one iteration. A comparison between the analytical and corresponding numerical procedures reflects the advantages of the first one. The accordance between the obtained results and the numerical ones highlights that the procedure used is accurate, effective, and good to implement in applications such as sliding mode control to the ball-and-plate problem. Full article

(This article belongs to the Special Issue Advances in the Control of Complex Dynamic Systems)

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