Processes

16 pages, 2788 KiB

Open AccessReview

Mapping Research on Microbial Fuel Cells in Wastewater Treatment: A Co-Citation Analysis

by Tianming Chen, Chao Zou, Jingjing Pan, Mansi Wang, Liang Qiao, Feihong Wang, Qi Zhao, Haoyi Cheng, Cheng Ding and Ye Yuan

Processes 2022, 10(1), 179; https://doi.org/10.3390/pr10010179 - 17 Jan 2022

Cited by 2 | Viewed by 3030

Abstract

Microbial fuel cells (MFCs) are promising technologies, aiming at treating different types of industrial and domestic wastewater. In recent years, more and more publications focusing on wastewater treatment have been published. Based on the retrieval of publications from Web of Science Core Collection [...] Read more.

Microbial fuel cells (MFCs) are promising technologies, aiming at treating different types of industrial and domestic wastewater. In recent years, more and more publications focusing on wastewater treatment have been published. Based on the retrieval of publications from Web of Science Core Collection database, the new emerging trends of microbial fuel cells in wastewater treatment was evaluated with a scientometric analysis method from 1995 to 2020. All publications downloaded from (WOS) were screened by inclusion criteria, and 2233 publications were obtained for further analysis. Document co-citation and burst detection of MFCs in wastewater treatment were analyzed and visualized by software of CiteSpace. Our study indicated that “Environmental Science” is the most popular discipline, while the journal of Bioresource Technology published the greatest quantity of articles in the field of MFCs applied wastewater treatment. China and the Chinese Academy of Science are the most productive country and institution, respectively. “Azo dye” has become the new research topic, which indicates the application area and the development of MFCs. The performance of MFCs for wastewater treatment has been widely discussed. The findings of this study may ameliorate the researcher in seizing the frontier of MFCs in wastewater treatment. Full article

(This article belongs to the Special Issue Recent Developments of Waste Water Technologies Based on Electrochemistry)

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13 pages, 1421 KiB

Open AccessFeature PaperArticle

Food Powder Flow in Extrusion: Role of Particle Size and Composition

by Cameron McGuire, Kaliramesh Siliveru, Kingsly Ambrose and Sajid Alavi

Processes 2022, 10(1), 178; https://doi.org/10.3390/pr10010178 - 17 Jan 2022

Cited by 11 | Viewed by 3991

Abstract

Innovations in food extrusion technology are enabling its rapid expansion and applicability in diverse areas related to bioprocessing and value addition. This study relates raw material particulate rheology to the granular flow in a single screw food extruder. Raw materials based on corn [...] Read more.

Innovations in food extrusion technology are enabling its rapid expansion and applicability in diverse areas related to bioprocessing and value addition. This study relates raw material particulate rheology to the granular flow in a single screw food extruder. Raw materials based on corn (i.e., meal, flour, and starch), wheat (i.e., farina, flour, and starch), and sucrose (i.e., granulated, superfine, and powdered) were used as model particulate systems for the study. Various particulate-scale characteristics and flow parameters of these nine materials were determined using a powder rheometer, a promising new offline tool. Properties such as basic flow energy, specific energy, cohesion, stability index, flow function, and effective angle of internal friction were good indicators of flowability in an extruder. Corn meal exhibited lower energy requirements and a higher propensity for flow than corn flour (6.7 mJ/g versus 10.7 mJ/g, and “free-flowing” versus “cohesive,” according to Flow Function classifications), with wheat farina showing similar results when compared to wheat flour (5.8 mJ/g versus 7.9 mJ/g, and “highly free-flowing versus “cohesive,” according to Flow Function classifications), although both wheat systems showed comparatively lower energy requirements than their comparable corn systems. Sugar, being of a different base material and particle shape, behaved differently than these starch-based materials—flow energy decreased and propensity to flow increased (51.7 mJ/g versus 8.0 mJ/g, and “free-flowing” versus “highly free-flowing”). This large energy requirement for coarse sugar particles may be attributed more to particle shape than composition, as the sharp edges of sugar can interlock and increase restriction to movement through the sample. The starch-based results were validated in a particulate flow study involving the above model systems (corn meal, corn flour, wheat farina, and wheat flour) in a pilot-scale single screw extruder. Visualization data, obtained using a transparent plexiglass window during extrusion, confirmed that the flours exhibited higher flow energy requirements and a lower flow factor when compared to the coarser-particle size corn meal during extrusion, seen by the increased peak heights and barrel fill. Full article

(This article belongs to the Special Issue Processing and Properties Analysis of Grain Foods)

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35 pages, 5454 KiB

Open AccessReview

A Review on Pool and Flow Boiling Enhancement Using Nanofluids: Nuclear Reactor Application

by Sayantan Mukherjee, Shikha Ebrahim, Purna Chandra Mishra, Naser Ali and Paritosh Chaudhuri

Processes 2022, 10(1), 177; https://doi.org/10.3390/pr10010177 - 17 Jan 2022

Cited by 21 | Viewed by 2739

Abstract

Plasma-facing components (PFCs) are used as the barrier to the beam of high heat flux generated due to nuclear fusion. Therefore, efficient cooling of PFCs is required for safety and smooth operation of a fusion reactor. The Hyper Vapotron (HV) is generally used [...] Read more.

Plasma-facing components (PFCs) are used as the barrier to the beam of high heat flux generated due to nuclear fusion. Therefore, efficient cooling of PFCs is required for safety and smooth operation of a fusion reactor. The Hyper Vapotron (HV) is generally used as the heat exchanger to cool down the PFCs during operation. These heat exchangers use pool and flow boiling mechanisms, and hence, their ability is inherently constrained by critical heat flux (CHF). The boiling of nanofluid is very promising as the working fluid in the HV. The efficiency of the HV increases due to the increase in CHF by applying nanofluids. However, the feasibility of nanofluid cooling in fusion reactors needs proper understanding. This paper reviews the recent developments in the utilization of boiling phenomena in nanofluid as a coolant in the HV. Experiments, theoretical studies, significant achievements, and challenges are analyzed and discussed. Finally, important points are indicated for future research. Full article

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25 pages, 876 KiB

Open AccessArticle

Analysis of Stock-Dependent Arrival Process in a Retrial Stochastic Inventory System with Server Vacation

by C. Sugapriya, M. Nithya, K. Jeganathan, N. Anbazhagan, Gyanendra Prasad Joshi, Eunmok Yang and Suseok Seo

Processes 2022, 10(1), 176; https://doi.org/10.3390/pr10010176 - 17 Jan 2022

Cited by 10 | Viewed by 2030

Abstract

The present study deals with the stock-dependent Markovian demand of a retrial queueing system with a single server and multiple server vacation. The items are restocked under a continuous review

(s, Q)

ordering policy. When there is no item in [...] Read more.

The present study deals with the stock-dependent Markovian demand of a retrial queueing system with a single server and multiple server vacation. The items are restocked under a continuous review

(s, Q)

ordering policy. When there is no item in the system, the server goes on vacation. Further, any arrival demand permits entry into an infinite orbit whenever the server is on vacation. In the Matrix geometric approach with the Neuts-Rao truncation technique, the steady-state joint distribution of the number of customers in orbit, the server status, and the inventory level is obtained. Under the steady-state conditions, some significant system performance measures, including the long-run total cost rate, are derived, and the Laplace-Stieltjes transform is also used to investigate the waiting time distribution. According to various considerations of uncontrollable parameters and costs, the merits of the proposed model, especially the important characteristics of the system with stock dependency over non-stock dependency, are explored. Ultimately, the important facts and ideas behind this model are given in conclusion. Full article

(This article belongs to the Collection Tools, Approaches and Modeling in Sustainable Supply Chain Management)

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11 pages, 1243 KiB

Open AccessCommunication

Clarification of Most Relevant Concepts Related to the Microalgae Production Sector

by Vítor Verdelho Vieira, Jean-Paul Cadoret, F. Gabriel Acien and John Benemann

Processes 2022, 10(1), 175; https://doi.org/10.3390/pr10010175 - 17 Jan 2022

Cited by 15 | Viewed by 3420

Abstract

Microalgae (including cyanobacteria) are the basis for an emerging worldwide industry but still face significant bottlenecks in contributing to the global economy. It is an enormous challenge to translate experiences from established industries such as aquaculture and agriculture to the microalgae sector. In [...] Read more.

Microalgae (including cyanobacteria) are the basis for an emerging worldwide industry but still face significant bottlenecks in contributing to the global economy. It is an enormous challenge to translate experiences from established industries such as aquaculture and agriculture to the microalgae sector. In particular, this includes the challenge of adapting regulations that apply to such macroscopic production and mindsets, to the microscopic world of microalgae and to the scale-up to a million times smaller. Current European and country-based regulations do not always, indeed rarely, consider relevant specific issues that limit the path for innovation and growth applicable to the microalgae sector. In this work, the boundaries for the main issues impacting this sector are presented and discussed. Examples and possible analytical frameworks are presented in a question and answer format. Relevant key topics and related boundaries are discussed: What are algae and how do microalgae differ from macroalgae? Why are algae and specifically microalgae relevant? Is algae cultivation an aquaculture process? Can algae and specifically microalgae be classified as vegetables and their production be classified as agriculture or are they an industrial process? How is algaculture compared with other agricultural sectors? What are organic algae? Can microalgae be grown in wastewater and how can they be used? What are toxic algae? What are the bottlenecks for microalgae culture scale-up? How does the microalgae biodiversity contribute to their development? We conclude that microalgae are developing as a novel agricultural enterprise that can provide major benefits to a sustainable circular economy and environment but require appropriate regulations and support from governments and businesses, recognising its unique attributes and potential. Full article

(This article belongs to the Special Issue Extraction, Exploitation and Application of Algae Biomass)

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18 pages, 23678 KiB

Open AccessFeature PaperReview

Matrix Acidizing in Carbonate Formations

by Ofelia Gomez Chacon and Maysam Pournik

Processes 2022, 10(1), 174; https://doi.org/10.3390/pr10010174 - 17 Jan 2022

Cited by 19 | Viewed by 7257

Abstract

Matrix acidizing in carbonate reservoirs is a process that has been long used to increase productivity in oil and gas producing formations. The main goal is to create wormholes that bypass the damage in the formation. Hydrochloric acid (HCl) is the main acid [...] Read more.

Matrix acidizing in carbonate reservoirs is a process that has been long used to increase productivity in oil and gas producing formations. The main goal is to create wormholes that bypass the damage in the formation. Hydrochloric acid (HCl) is the main acid used for this; however, it has several disadvantages that affect the success of these treatments. Its high reaction rate, inability to divert, and corrosive nature are a few of the reasons why research in this area has focused on finding alternative fluids. This paper discusses studies on successful alternatives to HCl. It has been observed that emulsified acids, which work with the addition of a surfactant to HCl, have shown positive results as their high viscosity allows them to retard the reaction rate between the acid and the rock and form effective and dominant wormholes. This is needed, especially in high-temperature environments. As HCl also lacks the ability to divert to low-permeability zones in highly heterogeneous formations, emulsified acids are also helpful for this task. While viscoelastic surfactants have been found to be less susceptible to form damage since they do not have any polymer content, their diversion performance has not been as effective as emulsified acids. Corrosion is one of the greatest and most expensive issues faced in matrix acidizing treatments. The use of corrosion inhibitors has been proposed as the best way to deal with this problem. Inorganic corrosion inhibitors are no longer an option as they are extremely toxic and pose a great danger to the environment. Organic corrosion inhibitors have been proposed as an alternative since the 1970s. However, organic compounds still pose a hazard in their use. Natural extracts as alternatives have been proposed for their inhibition ability. The use of henna extract and aqueous garlic peel extract as corrosion inhibitors has shown positive results with lower corrosion rates compared to some conventional inhibitors. Full article

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

20 pages, 4005 KiB

Open AccessArticle

Effects of Different Ethanol/Diesel Blending Ratios on Combustion and Emission Characteristics of a Medium-Speed Diesel Engine

by Zhiqiang Wang and Lijun Li

Processes 2022, 10(1), 173; https://doi.org/10.3390/pr10010173 - 17 Jan 2022

Cited by 4 | Viewed by 2734

Abstract

In order to better evaluate the effects of ethanol/diesel blends on engine combustion and emission characteristics, we developed an engine cylinder model using the software CONVERGE combined with the program CHEMKIN. The model was validated experimentally. A modified chemical kinetic mechanism was used [...] Read more.

In order to better evaluate the effects of ethanol/diesel blends on engine combustion and emission characteristics, we developed an engine cylinder model using the software CONVERGE combined with the program CHEMKIN. The model was validated experimentally. A modified chemical kinetic mechanism was used to calculate the combustion process of diesel fuel and ethanol for the diesel engine, including 154 reactions and 68 species. Furthermore, the influence of different ethanol proportions on diesel engine combustion and emission characteristics, including power, brake specific fuel consumption, brake thermal efficiency, cylinder pressure, cylinder temperature, nitrogen oxide (NO_x), carbon monoxide (CO), and soot emissions, was also investigated. Our results showed that cylinder pressure and temperature increased with increased ethanol content. When the ethanol content increased to 20% at 100% load, the cylinder pressure increased by 0.46%, and the thermal efficiency increased by 3.63%. However, due to the lower calorific value of ethanol, the power decreased by 4.12%, and the brake specific fuel consumption increased by 4.23%. In addition, the ethanol/diesel blends significantly reduced CO and soot emissions. Compared with diesel, soot and CO emissions from the D80E20 at 100% load reduced by 63.25% and 17.24%, respectively. However, NO_x emission increased by 1.39%. Full article

(This article belongs to the Special Issue Clean Combustion and Emission in Vehicle Power System)

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38 pages, 454 KiB

Open AccessFeature PaperReview

Significance of Chromatographic Techniques in Pharmaceutical Analysis

by Wioletta Parys, Małgorzata Dołowy and Alina Pyka-Pająk

Processes 2022, 10(1), 172; https://doi.org/10.3390/pr10010172 - 17 Jan 2022

Cited by 7 | Viewed by 8193

Abstract

This work presents an overview of the modern approaches embracing advanced equipment and validation parameters of both liquid and gas chromatography techniques, including thin-layer chromatography (TLC), column liquid chromatography (CLC), and gas chromatography (GC), suitable for the identification and quantitative determination of various [...] Read more.

This work presents an overview of the modern approaches embracing advanced equipment and validation parameters of both liquid and gas chromatography techniques, including thin-layer chromatography (TLC), column liquid chromatography (CLC), and gas chromatography (GC), suitable for the identification and quantitative determination of various bioactive compounds occurring in pharmaceutical products and medicinal plants in the time from 2020 to 2021 (November). This review confirmed that HPLC is an incredibly universal tool, especially when combined with different detectors, such as UV-Visible spectroscopy, mass spectrometry (MS), and fluorescence detection for numerous active ingredients in different pharmaceutical formulations without interferences from other excipients. TLC, in combination with densitometry, is a very efficient tool for the determination of biologically active substances present in pharmaceutical preparations. In addition, TLC coupled to densitometry and mass spectrometry could be suitable for preliminary screening and determination of the biological activity (e.g., antioxidant properties, thin layer chromatography (TLC) by 2,2-diphenyl-1-picrylhydrazyl (DPPH) method) of plant materials. Gas chromatography, coupled with a mass spectrometer (GC-MS, GC-MS/MS), is of particular importance in the testing of any volatile substances, such as essential oils. LC, coupled to NMR and MS, is the best solution for identifying and studying the structure of unknown components from plant extracts, as well as degradation products (DPs). Thanks to size-exclusion chromatography, coupled to multi-angle light scattering, the quality control of biological pharmaceuticals is possible. Full article

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

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Graphical abstract

12 pages, 2500 KiB

Open AccessArticle

Prediction of PM2.5 Concentration on the Basis of Multi-Time Scale Fusion

by Jianfei Zhang and Wangui Xia

Processes 2022, 10(1), 171; https://doi.org/10.3390/pr10010171 - 17 Jan 2022

Cited by 1 | Viewed by 1354

Abstract

Long-term prediction of hour-concentration of PM2.5 (particles in atmospheric suspension with effective dimensions equal or lower than 2.5 microns) is of great significance for environmental protection and people’s health. At present, the prediction of hour-concentration of PM2.5 is mostly single-step prediction, which is [...] Read more.

Long-term prediction of hour-concentration of PM2.5 (particles in atmospheric suspension with effective dimensions equal or lower than 2.5 microns) is of great significance for environmental protection and people’s health. At present, the prediction of hour-concentration of PM2.5 is mostly single-step prediction, which is to predict PM2.5 concentration at a future time point based on a period of historical data. In this paper, a model based on multi-time scale fusion is proposed to study single-step prediction and multi-step prediction, respectively. Experimental results show that the proposed model is better than stacked LSTM and CNN-LSTM in predicting PM2.5 hour-concentration. Full article

(This article belongs to the Special Issue Air Quality Monitoring for Smart Cities and Industrial Applications)

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16 pages, 4143 KiB

Open AccessArticle

Detoxification of Copper and Chromium via Dark Hydrogen Fermentation of Potato Waste by Clostridium butyricum Strain 92

by Vira Hovorukha, Olesia Havryliuk, Galina Gladka, Antonina Kalinichenko, Monika Sporek, Jan Stebila, Dmitri Mavrodi, Ruslan Mariychuk and Oleksandr Tashyrev

Processes 2022, 10(1), 170; https://doi.org/10.3390/pr10010170 - 17 Jan 2022

Viewed by 1708

Abstract

The accumulation of various types of waste containing both organic and inorganic metal-containing compounds is extremely hazardous for living organisms. The possibility of polymer degradation, biohydrogen synthesis, and metal detoxification via the dark fermentation of model potato waste was investigated. For this purpose, [...] Read more.

The accumulation of various types of waste containing both organic and inorganic metal-containing compounds is extremely hazardous for living organisms. The possibility of polymer degradation, biohydrogen synthesis, and metal detoxification via the dark fermentation of model potato waste was investigated. For this purpose, the strict anaerobic strain was isolated and identified as Clostridium butyricum. The high efficiency of dark hydrogen fermentation of potatoes with yield of hydrogen in 85.8 ± 15.3 L kg⁻¹ VS_potato was observed. The copperand chromium salts solutions were added to the culture fluid to obtain the concentrations of 50, 100, and 200 mg L⁻¹ Cu(II) and Cr(VI) in the active phase of growth (19 h of cultivation). Metals at a concentration of 200 mg L⁻¹ inhibited the fermentation process the most. The hydrogen yield decreased in 7.2 and 3.6 times to 11.9 ± 2.1 and 23.8 ± 5.6 L kg⁻¹ VSpotato in the presence of 200 mg L⁻¹ Cu(II) and Cr(VI), respectively. The efficiencies of the chromium bioremoval in all variants of the experiment were 100%, and those of copper bioremoval were about 90%. A pure culture of strict anaerobes Clostridium butyricum strain 92 was used for the first time for the detoxification of metals. The presented results confirmed the possibility of this promising strain application for industrial H₂ production and the bioremediation of contaminated sites. Full article

(This article belongs to the Special Issue Bioactive Compounds from Food Waste and By-Products)

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12 pages, 2289 KiB

Open AccessFeature PaperArticle

Nonstationary Process Monitoring Based on Cointegration Theory and Multiple Order Moments

by Jiatao Wen, Yang Li, Jingde Wang and Wei Sun

Processes 2022, 10(1), 169; https://doi.org/10.3390/pr10010169 - 17 Jan 2022

Cited by 5 | Viewed by 1661

Abstract

In industrial processes, process data often exhibit complex characteristics, such as nonstationarity and nonlinearity, which brings challenges to process monitoring. In this study, a monitoring strategy for nonstationary processes is proposed based on cointegration theory and multiple order moments. Considering the nonstationarity presented [...] Read more.

In industrial processes, process data often exhibit complex characteristics, such as nonstationarity and nonlinearity, which brings challenges to process monitoring. In this study, a monitoring strategy for nonstationary processes is proposed based on cointegration theory and multiple order moments. Considering the nonstationarity presented in some variables, cointegration analysis (CA) is applied to obtain long-term equilibrium relationships among these nonstationary variables, which are then combined with stationary variables to form a new stationary dataset. For the purpose of process monitoring, a new monitoring index that contains multiple order moments is proposed to capture different statistical features of a previously obtained stationary data set. Moving windows are applied to capture changes of local statistical characteristics to implement online monitoring. Case studies on simulation data and an industrial dataset are presented to illustrate the effectiveness of the proposed method for nonstationary process monitoring. Comparing with the PCA and common CA-based monitoring methods, the proposed method has better performance with a lower false alarm rate and earlier alarm time. Full article

(This article belongs to the Section Process Control and Monitoring)

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11 pages, 1902 KiB

Open AccessArticle

Experimental Study on the Crushing Properties of Corn Stalks in Square Bales

by Jie Zhang, Bin Feng, Xiuzhen Yu, Chao Zhao, Hao Li and Za Kan

Processes 2022, 10(1), 168; https://doi.org/10.3390/pr10010168 - 16 Jan 2022

Cited by 2 | Viewed by 1955

Abstract

With the development of straw baling mechanization technology, straw is stored in the form of square baling or round baling. At present, hammer mill or the guilt-cutting and rubbing combined mill is widely used to crush square bales of straw. These two kinds [...] Read more.

With the development of straw baling mechanization technology, straw is stored in the form of square baling or round baling. At present, hammer mill or the guilt-cutting and rubbing combined mill is widely used to crush square bales of straw. These two kinds of crushing equipment have disadvantages such as low productivity, large power consumption, and poor crushing effect. This paper aims to study and analyze the crushing characteristics of square baled straw after unbaling, and lay a theoretical foundation for the later research and development of a special square baled straw crusher with high productivity, low power consumption, good crushing effect, and the simulation of the square baled corn straw crushing process. For this purpose, this study carried out a corn bale crushing experiment on the Instron 8801 fatigue test machine, and studied the effects of blade angle, water content and loading speed on corn bale crushing force through the response surface method. Test results showed that the crushing process includes the compression stage and shearing stage; in terms of single factor effect, with the increase in water content and blade angle, the crushing force of the corn bale increased, but the loading speed had no significant effect on the crushing force of the corn bale. In terms of interaction effect, there was interaction effect between moisture content and blade inclination angle, when moisture content was 10%, with the increase in blade inclination angle, the incremental speed of the crushing force also increased gradually. When the blade inclination angle was 10°, with the increase in moisture content, the incremental speed of the crushing force also increased, and the interaction effect of them jointly acted on the crushing force of the corn bales. Full article

(This article belongs to the Special Issue Lignocellulose Pretreatment and Utilization)

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17 pages, 3398 KiB

Open AccessFeature PaperArticle

Numerical Analysis of Effects of Specularity Coefficient and Restitution Coefficient on the Hydrodynamics of Particles in a Rotating Drum

by Rezwana Rahman, Haiping Zhu and Aibing Yu

Processes 2022, 10(1), 167; https://doi.org/10.3390/pr10010167 - 15 Jan 2022

Cited by 4 | Viewed by 2013

Abstract

Various simulations have been conducted to understand the macroscopic behavior of particles in the solid-gas flow in rotating drums in the past. In these studies, the no-slip wall boundary condition and fixed restitution coefficient between particles were usually adopted. The paper presents a [...] Read more.

Various simulations have been conducted to understand the macroscopic behavior of particles in the solid-gas flow in rotating drums in the past. In these studies, the no-slip wall boundary condition and fixed restitution coefficient between particles were usually adopted. The paper presents a numerical study of the gas-solid flow in a rotating drum to understand the effect of the specularity coefficient and restitution coefficient on the hydrodynamic behavior of particles in the segregation process. The volume fraction, granular pressure, granular temperature and their relationships are examined in detail. The boundary conditions of the no-slip and specularity coefficient of 1 are compared. In the simulations, two different sizes of particles with the same density are considered and the Eulerian–Eulerian multiphase model and the kinetic theory of granular flow (KTGF) are used. The results reveal that the hydrodynamical behavior of the particles in the rotating drum is affected by the boundary condition and restitution coefficient. In particular, the increase of specularity coefficient can increase the active region depth, angle repose, granular pressure for both small and large particles and granular temperature for large particles. With increasing restitution coefficient, the angle of repose decreases and granular pressure and temperature increase at the same volume fraction for both small and large particles. Full article

(This article belongs to the Section Particle Processes)

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13 pages, 3941 KiB

Open AccessFeature PaperArticle

High-Throughput Computational Screening of Ionic Liquids for Butadiene and Butene Separation

by Hao Qin, Zihao Wang, Zhen Song, Xiang Zhang and Teng Zhou

Processes 2022, 10(1), 165; https://doi.org/10.3390/pr10010165 - 15 Jan 2022

Cited by 3 | Viewed by 2122

Abstract

The separation of 1,3-butadiene (1,3-C₄H₆) and 1-butene (n-C₄H₈) is quite challenging due to their close boiling points and similar molecular structures. Extractive distillation (ED) is widely regarded as a promising approach for such a separation [...] Read more.

The separation of 1,3-butadiene (1,3-C₄H₆) and 1-butene (n-C₄H₈) is quite challenging due to their close boiling points and similar molecular structures. Extractive distillation (ED) is widely regarded as a promising approach for such a separation task. For ED processes, the selection of suitable entrainer is of central importance. Traditional ED processes using organic solvents suffer from high energy consumption. To tackle this issue, the utilization of ionic liquids (ILs) can serve as a potential alternative. In this work, a high-throughput computational screening of ILs is performed to find proper entrainers, where 36,260 IL candidates comprising of 370 cations and 98 anions are involved. COSMO-RS is employed to calculate the infinite dilution extractive capacity and selectivity of the 36,260 ILs. In doing so, the ILs that satisfy the prespecified thermodynamic criteria and physical property constraints are identified. After the screening, the resulting IL candidates are sent for rigorous process simulation and design. 1,2,3,4,5-pentamethylimidazolium methylcarbonate is found to be the optimal IL solvent. Compared with the benchmark ED process where the organic solvent N-methyl-2-pyrrolidone is adopted, the energy consumption is reduced by 26%. As a result, this work offers a new IL-based ED process for efficient 1,3-C₄H₆ production. Full article

(This article belongs to the Special Issue Redesign Processes in the Age of the Fourth Industrial Revolution)

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13 pages, 3478 KiB

Open AccessArticle

(S)-5-Methylmellein Isolated from an Endogenous Lichen Fungus Rosellinia corticium as a Potent Inhibitor of Human Monoamine Oxidase A

by Geum-Seok Jeong, Eun-Young Lee, Myung-Gyun Kang, Sang-Jip Nam, Daeui Park and Hoon Kim

Processes 2022, 10(1), 166; https://doi.org/10.3390/pr10010166 - 14 Jan 2022

Cited by 5 | Viewed by 1714

Abstract

In this study, the inhibitory activities against human monoamine oxidases (hMAOs) were evaluated using a library of 195 endogenous lichen fungi from Ukraine. Among them, the extract ELF68 of the endogenous fungus Rosellinia corticium from the lichen Pseudevernia furfuracea (L.) Zopf. exhibited the [...] Read more.

In this study, the inhibitory activities against human monoamine oxidases (hMAOs) were evaluated using a library of 195 endogenous lichen fungi from Ukraine. Among them, the extract ELF68 of the endogenous fungus Rosellinia corticium from the lichen Pseudevernia furfuracea (L.) Zopf. exhibited the strongest inhibitory activity against hMAO-A. Using the activity-guided method, (S)-5-methylmellein (5MM) was isolated from the extract and had an IC₅₀ value of 5.31 µM for hMAO-A with a lower potency for hMAO-B (IC₅₀ = 9.15 µM). Compound 5MM also moderately inhibited acetylcholinesterase (IC₅₀ = 27.07 µM) but very weakly inhibited butyrylcholinesterase and β-secretase. Compound 5MM had a K_i value of 2.45 μM and was a reversible competitive inhibitor of hMAO-A. A molecular docking study predicted that (S)-5MM showed higher binding affinity for hMAO-A (−6.8 kcal/mol) than hMAO-B (−6.4 kcal/mol). Its isomer, (R)-5MM, exhibited lower binding affinities for hMAO-A (−6.6 kcal/mol) and hMAO-B (−5.2 kcal/mol), compared to (S)-5MM. The S-form interacted with hMAO-A through hydrogen bonding with the Phe208 residue (distance: 1.972 Å), while the R-form interacted with the Asn181 residue (2.375 Å). The results of an in silico pharmacokinetic analysis indicated that 5MM did not violate Lipinski’s five rules and showed high gastrointestinal absorption and blood–brain barrier permeability. These results suggest that 5MM can be considered a candidate in the treatment of neuropsychiatric disorders, such as depression and cardiovascular disease. Full article

(This article belongs to the Special Issue Pharmaceutical Development and Bioavailability Analysis)

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21 pages, 1796 KiB

Open AccessFeature PaperArticle

Effect of Gum Arabic and Starch-Based Coating and Different Polyliners on Postharvest Quality Attributes of Whole Pomegranate Fruit

by Tatenda Gift Kawhena, Umezuruike Linus Opara and Olaniyi Amos Fawole

Processes 2022, 10(1), 164; https://doi.org/10.3390/pr10010164 - 14 Jan 2022

Cited by 9 | Viewed by 2023

Abstract

This study investigated the effect of gum Arabic and starch-based coating and two polyliners (Liner 1-micro-perforated Xtend^® and Liner 2-macro-perforated high-density polyethylene) on whole ‘Wonderful’ pomegranate fruit during cold storage (5 ± 1 °C and 95 ± 2% RH). Uncoated (UC) and [...] Read more.

This study investigated the effect of gum Arabic and starch-based coating and two polyliners (Liner 1-micro-perforated Xtend^® and Liner 2-macro-perforated high-density polyethylene) on whole ‘Wonderful’ pomegranate fruit during cold storage (5 ± 1 °C and 95 ± 2% RH). Uncoated (UC) and coated (GA_MS) fruit were packaged into standard open top ventilated cartons (dimensions: 0.40 m long, 0.30 m wide and 0.12 m high) with (GA_MS + Liner 1, GA_MS + Liner 2, UC + Liner 1 and UC + Liner 2) or without (UC and GA_MS) polyliners. After 42 d, treatment GA_MS + Liner 1 recorded the least weight loss (4.82%), whilst GA_MS recorded lower (8.77%) weight loss than UC + Liner 2 (10.07%). The highest (24.74 mLCO₂ kg⁻¹h⁻¹) and lowest (13.14 mLCO₂ kg⁻¹h⁻¹) respiration rates were detected in UC and GA_MS + Liner 1, respectively. The highest and lowest total soluble solids were recorded for GA_MS (16.87 °Brix), and GA_MS + Liner 1 (15.60 °Brix) and UC + Liner 1 (15.60 °Brix), respectively. Overall, no decay was detected for coated fruit packaged with either Liner 1 or Liner 2. Therefore, the combination of GA_MS with Xtend^® polyliners proved to be an effective treatment to maintain the quality of ‘Wonderful’ pomegranates during storage. Full article

(This article belongs to the Special Issue Technological Advancements in Food Processing and Packaging)

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7 pages, 2762 KiB

Open AccessFeature PaperArticle

Nanoporous Layers and the Peculiarities of Their Local Formation on a Silicon Wafer

by Vitali Vasil’evich Starkov, Ekaterina Alexanrovna Gosteva, Dmitry Dmitry Zherebtsov, Maxim Vladimirovich Chichkov and Nikita Valerievich Alexandrov

Processes 2022, 10(1), 163; https://doi.org/10.3390/pr10010163 - 14 Jan 2022

Cited by 1 | Viewed by 1882

Abstract

This review presents the results of the local formation of nanostructured porous silicon (NPSi) on the surface of silicon wafers by anodic etching using a durite intermediate ring. The morphological and crystallographic features of NPSi structures formed on n- and p-type silicon with [...] Read more.

This review presents the results of the local formation of nanostructured porous silicon (NPSi) on the surface of silicon wafers by anodic etching using a durite intermediate ring. The morphological and crystallographic features of NPSi structures formed on n- and p-type silicon with low and relatively high resistivity have also been investigated. The proposed scheme allows one to experiment with biological objects (for example, stem cells, neurons, and other objects) in a locally formed porous structure located in close proximity to the electronic periphery of sensor devices on a silicon wafer. Full article

(This article belongs to the Special Issue Hierarchical Porous Materials: Synthesis, Properties and Applications)

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13 pages, 2380 KiB

Open AccessFeature PaperArticle

Secreted Trimeric Chikungunya Virus Spikes from Insect Cells: Production, Purification, and Glycosylation Status

by Tessy A. H. Hick, Corinne Geertsema, Maurice G. L. Henquet, Dirk E. Martens, Stefan W. Metz and Gorben P. Pijlman

Processes 2022, 10(1), 162; https://doi.org/10.3390/pr10010162 - 14 Jan 2022

Cited by 1 | Viewed by 2574

Abstract

Chikungunya virus (CHIKV) is a rapidly emerging mosquito-borne virus that causes a severe febrile illness with long-lasting arthralgia in humans. As there is no vaccine to protect humans and limit CHIKV epidemics, the virus continues to be a global public health concern. The [...] Read more.

Chikungunya virus (CHIKV) is a rapidly emerging mosquito-borne virus that causes a severe febrile illness with long-lasting arthralgia in humans. As there is no vaccine to protect humans and limit CHIKV epidemics, the virus continues to be a global public health concern. The CHIKV envelope glycoproteins E1 and E2 are important immunogens; therefore, the aim of this study is to produce trimeric CHIKV spikes in insect cells using the baculovirus expression system. The CHIKV E1 and E2 ectodomains were covalently coupled by a flexible linker that replaces the 6K transmembrane protein. The C-terminal E1 transmembrane was replaced by a Strep-tag II for the purification of secreted spikes from the culture fluid. After production in Sf9 suspension cells (product yields of 5.8–7.6 mg/L), the CHIKV spikes were purified by Strep-Tactin affinity chromatography, which successfully cleared the co-produced baculoviruses. Bis(sulfosuccinimidyl)suberate cross-linking demonstrated that the spikes are secreted as trimers. PNGase F treatment showed that the spikes are glycosylated. LC–MS/MS-based glycoproteomic analysis confirmed the glycosylation and revealed that the majority are of the mannose- or hybrid-type N-glycans and <2% have complex-type N-glycans. The LC –MS/MS analysis also revealed three O-glycosylation sites in E1. In conclusion, the trimeric, glycosylated CHIKV spikes have been successfully produced in insect cells and are now available for vaccination studies. Full article

(This article belongs to the Special Issue State of the Art of Protein Expression Systems)

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13 pages, 2364 KiB

Open AccessArticle

Design and Development of Innovative Steam Injection for High-Temperature Short-Time Liquid Foods

by Wilasinee Sangsom and Chouw Inprasit

Processes 2022, 10(1), 161; https://doi.org/10.3390/pr10010161 - 14 Jan 2022

Cited by 3 | Viewed by 2043

Abstract

Jet impingement has been effective in reducing the process time and improvement of product quality in various industrial applications, such as textile and paper drying, electronic cooling, glass quenching and food processing. The current work applied innovative steam injection to liquid food continuous [...] Read more.

Jet impingement has been effective in reducing the process time and improvement of product quality in various industrial applications, such as textile and paper drying, electronic cooling, glass quenching and food processing. The current work applied innovative steam injection to liquid food continuous sterilization. The multiple impingement jets of steam and product came together in the impingement tank. The effects were investigated on the Reynolds number, steam temperature and jet-to-target spacing (H/d), sterilization temperature and heat transfer efficiency in water and pineapple juice tests. The Reynolds number was based on the nozzle configuration and liquid flow rate. The study investigated product injection plates formed using two, three or four circular holes (diameter 2 mm), steam injection plates with six, nine or twenty circular holes (diameter 1 mm), steam temperatures of 120, 125 or 130 °C and H/d values of 1, 3, 5 or 7. The different options were tested with water to determine the optimal conditions, and then tested with pineapple juice. The results showed that the optimal conditions from water testing that provided the highest heat transfer efficiency occurred with two jet nozzles, six steam injection plates, a steam temperature of 120 °C and an H/d value of 1. Full article

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14 pages, 2789 KiB

Open AccessArticle

Application of Various Machine Learning Models for Process Stability of Bio-Electrochemical Anaerobic Digestion

by Ain Cheon, Jwakyung Sung, Hangbae Jun, Heewon Jang, Minji Kim and Jungyu Park

Processes 2022, 10(1), 158; https://doi.org/10.3390/pr10010158 - 14 Jan 2022

Cited by 15 | Viewed by 2047

Abstract

The application of a machine learning (ML) model to bio-electrochemical anaerobic digestion (BEAD) is a future-oriented approach for improving process stability by predicting performances that have nonlinear relationships with various operational parameters. Five ML models, which included tree-, regression-, and neural network-based algorithms, [...] Read more.

The application of a machine learning (ML) model to bio-electrochemical anaerobic digestion (BEAD) is a future-oriented approach for improving process stability by predicting performances that have nonlinear relationships with various operational parameters. Five ML models, which included tree-, regression-, and neural network-based algorithms, were applied to predict the methane yield in BEAD reactor. The results showed that various 1-step ahead ML models, which utilized prior data of BEAD performances, could enhance prediction accuracy. In addition, 1-step ahead with retraining algorithm could improve prediction accuracy by 37.3% compared with the conventional multi-step ahead algorithm. The improvement was particularly noteworthy in tree- and regression-based ML models. Moreover, 1-step ahead with retraining algorithm showed high potential of achieving efficient prediction using pH as a single input data, which is plausibly an easier monitoring parameter compared with the other parameters required in bioprocess models. Full article

(This article belongs to the Special Issue Bioelectrochemical System for Wastewater Treatment and Energy Recovery)

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15 pages, 5263 KiB

Open AccessArticle

Sensitivity Test of Jet Velocity and Void Fraction on the Prediction of Rise Height and Performance of a Confined Plunging Liquid Jet Reactor

by Bader S. Al-Anzi and Jenifer Fernandes

Processes 2022, 10(1), 160; https://doi.org/10.3390/pr10010160 - 13 Jan 2022

Cited by 5 | Viewed by 1761

Abstract

Jet velocity is an important parameter affecting the air entrainment rate of plunging liquid jet processes. While the vast majority of researchers have investigated the effect of jet velocity, only a few of them considered the effect of jet length in calculating the [...] Read more.

Jet velocity is an important parameter affecting the air entrainment rate of plunging liquid jet processes. While the vast majority of researchers have investigated the effect of jet velocity, only a few of them considered the effect of jet length in calculating the jet velocity at impingement point. This study investigates the difference (ΔV) between the jet velocity at the inception of the nozzle (V_j) and the impingement point (V_L) for a range of operating conditions. Furthermore, bubble voidage inside the downcomer, another critical parameter in plunging jets, is estimated using three different voidage equations incorporated inside a momentum balance model to predict the two-phase elevation level (H_R) inside the downcomer. Results showed that ΔV is significant (V_L > V_j), especially at low jet flow rates and high jet lengths. Generally, the momentum balance model predicted the H_R well, and its prediction improves with downcomer diameter. Given that, the model still needs to be refined for more accuracy for a wide range of operating conditions. Full article

(This article belongs to the Special Issue Complex Fluid Dynamics Modeling and Simulation)

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15 pages, 2189 KiB

Open AccessArticle

Sintering and Smelting Property Investigations of Ludwigite

by Gongjin Cheng, Xuezhi Liu, He Yang, Xiangxin Xue and Lanjie Li

Processes 2022, 10(1), 159; https://doi.org/10.3390/pr10010159 - 13 Jan 2022

Cited by 7 | Viewed by 1257

Abstract

In this paper, orthogonal experiments are designed to study the sintering and smelting characteristics of the ludwigite ore. The predominant influencing factors of the optimal ratio, basicity and carbon content on different single sintering indexes, including the vertical sintering speed, yield rate, drum [...] Read more.

In this paper, orthogonal experiments are designed to study the sintering and smelting characteristics of the ludwigite ore. The predominant influencing factors of the optimal ratio, basicity and carbon content on different single sintering indexes, including the vertical sintering speed, yield rate, drum strength and low-temperature reduction pulverization index, are firstly explored by the range analysis method, and the main influencing factors on comprehensive indexes are obtained by a weighted scoring method based on different single index investigation. Considering the sintering characteristics, the primary and secondary influencing factors are: ordinary ore ratio, carbon content and basicity, and the optimal ore blending scheme is: basicity 1.7, ordinary ore blending ratio 60% and carbon content 5%. In terms of the smelting characteristics, the research obtains the order of the influencing factors on the softening start temperature, softening end temperature, softening zone, smelting start temperature, dripping temperature, smelting-dripping zone, maximum pressure difference and gas permeability index of the ludwigite sinters by simply considering various single smelting indexes. On this basis, considering the comprehensive softening-melting-dripping characteristics, the primary and secondary influencing factors are: carbon content, ordinary ore ratio and basicity, and the optimal ore blending scheme is: basicity 1.9, ordinary ore blending ratio 60% and a carbon content of 5.5%. Comprehensively, considering the sintering and smelting property of the ludwigite ore, the primary and secondary influencing factors are: carbon content, ordinary ore ratio and basicity, and the optimal ore blending scheme is: basicity 1.9, ordinary ore blending ratio 60% and a carbon content of 5.5%. Full article

(This article belongs to the Section Environmental and Green Processes)

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20 pages, 47159 KiB

Open AccessArticle

Optimization Analysis of Locomotive Diesel Engine Intake System Based on Matlab-Simulink and GT-Power

by Feng Jiang, Wentong Cao, Xueyou Tan, Jie Hu, Junming Zhou and Zedan Tan

Processes 2022, 10(1), 157; https://doi.org/10.3390/pr10010157 - 13 Jan 2022

Cited by 5 | Viewed by 2043

Abstract

In this paper, based on the coupling calculation of Simulink software and GT-Power software, an Optimizer model method was proposed for a 16V265H diesel engine to study the effects of different ratios of biodiesel (B0, B10, and B20) on the performance of a [...] Read more.

In this paper, based on the coupling calculation of Simulink software and GT-Power software, an Optimizer model method was proposed for a 16V265H diesel engine to study the effects of different ratios of biodiesel (B0, B10, and B20) on the performance of a 16V265H diesel engine at 1000 rpm and 75% load. Firstly, the four parameters of diesel engine power, BSFC, soot emission, and NO_x emission were taken as the result variables of the optimization model. Taking the intake and exhaust timing of the diesel engine as the independent variable of the optimization model, the maximum power, minimum BSFC, and minimum diesel engine emission were studied and analyzed. Finally, the performance parameters were comprehensively analyzed to determine the best intake and exhaust valve timing. Moreover, based on the model optimization, the diesel engine’s BSFC and power performance were compared, and the optimal intake timing scheme for the diesel engine with different biodiesel ratios at 75% operating conditions was obtained. The results showed that the maximum power, optimum BSFC, and minimum emissions of the 16V265H diesel engine with different ratios of biodiesel and different intake valve timing angles were also different. Under 75% load conditions, the BSFC reduction rate was up to 6.32%, and the power increase rate was up to 5.87%. In addition, by optimizing the model with B10 biodiesel and the intake valve timing close to 202°CA and the exhaust valve timing close to 98°CA, the diesel engine had the lowest NO_x emission; with B10 biodiesel and the intake timing at 180°CA, the diesel engine had the lowest BSFC; and with B10 biodiesel and the intake valve timing close to 179.5°CA, the diesel engine had the maximum power. In conclusion, the diesel engine is best with B10 biodiesel. This research method can provide a reference for implementing variable intake system technology for the 16V265H diesel engine. Full article

(This article belongs to the Special Issue Clean Combustion and Emission in Vehicle Power System)

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16 pages, 2937 KiB

Open AccessFeature PaperReview

Hydrogen Production from Biomass and Organic Waste Using Dark Fermentation: An Analysis of Literature Data on the Effect of Operating Parameters on Process Performance

by Rita Noelle Moussa, Najah Moussa and Davide Dionisi

Processes 2022, 10(1), 156; https://doi.org/10.3390/pr10010156 - 13 Jan 2022

Cited by 28 | Viewed by 4759

Abstract

In the context of hydrogen production from biomass or organic waste with dark fermentation, this study analysed 55 studies (339 experiments) in the literature looking for the effect of operating parameters on the process performance of dark fermentation. The effect of substrate concentration, [...] Read more.

In the context of hydrogen production from biomass or organic waste with dark fermentation, this study analysed 55 studies (339 experiments) in the literature looking for the effect of operating parameters on the process performance of dark fermentation. The effect of substrate concentration, pH, temperature, and residence time on hydrogen yield, productivity, and content in the biogas was analysed. In addition, a linear regression model was developed to also account for the effect of nature and pretreatment of the substrate, inhibition of methanogenesis, and continuous or batch operating mode. The analysis showed that the hydrogen yield was mainly affected by pH and residence time, with the highest yields obtained for low pH and short residence time. High hydrogen productivity was favoured by high feed concentration, short residence time, and low pH. More modest was the effect on the hydrogen content. The mean values of hydrogen yield, productivity, and content were, respectively, 6.49% COD COD⁻¹, 135 mg L⁻¹ d⁻¹, 51% v/v, while 10% of the considered experiments obtained yield, productivity, and content of or higher than 15.55% COD COD⁻¹, 305.16 mg L⁻¹ d⁻¹, 64% v/v. Overall, this study provides insight into how to select the optimum operating conditions to obtain the desired hydrogen production. Full article

(This article belongs to the Topic Anaerobic Digestion Processes)

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27 pages, 2657 KiB

Open AccessReview

Mathematical Models for Cholesterol Metabolism and Transport

by Fangyuan Zhang, Brittany Macshane, Ryan Searcy and Zuyi Huang

Processes 2022, 10(1), 155; https://doi.org/10.3390/pr10010155 - 13 Jan 2022

Cited by 3 | Viewed by 4843

Abstract

Cholesterol is an essential component of eukaryotic cellular membranes. It is also an important precursor for making other molecules needed by the body. Cholesterol homeostasis plays an essential role in human health. Having high cholesterol can increase the chances of getting heart disease. [...] Read more.

Cholesterol is an essential component of eukaryotic cellular membranes. It is also an important precursor for making other molecules needed by the body. Cholesterol homeostasis plays an essential role in human health. Having high cholesterol can increase the chances of getting heart disease. As a result of the risks associated with high cholesterol, it is imperative that studies are conducted to determine the best course of action to reduce whole body cholesterol levels. Mathematical models can provide direction on this. By examining existing models, the suitable reactions or processes for drug targeting to lower whole-body cholesterol can be determined. This paper examines existing models in the literature that, in total, cover most of the processes involving cholesterol metabolism and transport, including: the absorption of cholesterol in the intestine; the cholesterol biosynthesis in the liver; the storage and transport of cholesterol between the intestine, the liver, blood vessels, and peripheral cells. The findings presented in these models will be discussed for potential combination to form a comprehensive model of cholesterol within the entire body, which is then taken as an in-silico patient for identifying drug targets, screening drugs, and designing intervention strategies to regulate cholesterol levels in the human body. Full article

(This article belongs to the Special Issue Feature Review Papers in Advanced Process Systems Engineering)

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22 pages, 7451 KiB

Open AccessArticle

Solar Carbo-Thermal and Methano-Thermal Reduction of MgO and ZnO for Metallic Powder and Syngas Production by Green Extractive Metallurgy

by Srirat Chuayboon and Stéphane Abanades

Processes 2022, 10(1), 154; https://doi.org/10.3390/pr10010154 - 13 Jan 2022

Cited by 7 | Viewed by 2004

Abstract

The solar carbo-thermal and methano-thermal reduction of both MgO and ZnO were performed in a flexible solar reactor operated at low pressure through both batch and continuous operations. The pyro-metallurgical process is an attractive sustainable pathway to convert and store concentrated solar energy [...] Read more.

The solar carbo-thermal and methano-thermal reduction of both MgO and ZnO were performed in a flexible solar reactor operated at low pressure through both batch and continuous operations. The pyro-metallurgical process is an attractive sustainable pathway to convert and store concentrated solar energy into high-value metal commodities and fuels. Substituting fossil fuel combustion with solar energy when providing high-temperature process heat is a relevant option for green extractive metallurgy. In this study, a thermodynamic equilibrium analysis was first performed to compare the thermochemical reduction of MgO and ZnO with solid carbon or gaseous methane, and to determine the product distribution as a function of the operating conditions. The carbo-thermal and methano-thermal reduction of the MgO and ZnO volatile oxides was then experimentally assessed and compared using a directly irradiated cavity-type solar reactor under different operating conditions, varying the type of carbon-based reducing agent (either solid carbon or methane), temperature (in the range 765–1167 °C for ZnO and 991–1550 °C for MgO), total pressure (including both reduced 0.10–0.15 bar and atmospheric ~0.90 bar pressures), and processing mode (batch and continuous operations). The carbo-thermal and methano-thermal reduction reactions yielded gaseous metal species (Mg and Zn) which were recovered at the reactor outlet as fine and reactive metal powders. Reducing the total pressure favored the conversion of both MgO and ZnO and increased the yields of Mg and Zn. However, a decrease in the total pressure also promoted CO₂ production because of a shortened gas residence time, especially in the case of ZnO reduction, whereas CO₂ formation was negligible in the case of MgO reduction, whatever the conditions. Continuous reactant co-feeding (corresponding to the mixture of metal oxide and carbon or methane) was also performed during the solar reactor operation, revealing an increase in both gas production yields and reaction extent while increasing the reactant feeding rate. The type of carbon reducer influenced the reaction extent, since a higher conversion of both MgO and ZnO was reached when using carbon with a highly available specific surface area for the reactions. The continuous solar process yielded high-purity magnesium and zinc content in the solar-produced metallic powders, thus confirming the reliability, flexibility, and robustness of the solar reactor and demonstrating a promising solar metallurgical process for the clean conversion of both metal oxides and concentrated solar light to value-added chemicals. Full article

(This article belongs to the Section Sustainable Processes)

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23 pages, 2969 KiB

Open AccessFeature PaperReview

Solar Desalination Driven by Organic Rankine Cycles (Orc) and Supercritical CO₂ Power Cycles: An Update

by Agustín M. Delgado-Torres and Lourdes García-Rodríguez

Processes 2022, 10(1), 153; https://doi.org/10.3390/pr10010153 - 13 Jan 2022

Cited by 9 | Viewed by 2704

Abstract

In the field of desalination powered by renewable energies, the use of solar power cycles exhibits some favorable characteristics, such as the possibility of implementing thermal energy storage systems or a multi-generation scheme (e.g., electricity, water, cooling, hydrogen). This article presents a review [...] Read more.

In the field of desalination powered by renewable energies, the use of solar power cycles exhibits some favorable characteristics, such as the possibility of implementing thermal energy storage systems or a multi-generation scheme (e.g., electricity, water, cooling, hydrogen). This article presents a review of the latest design proposals in which two power cycles of great potential are considered: the organic Rankine cycle and the supercritical CO₂ power cycle, the latter of growing interest in recent years. The designs found in the literature are grouped into three main types of systems. In the case of solar ORC-based systems, the option of reverse osmosis as a desalination technology is considered in medium-temperature solar systems with storage but also with low-temperature using solar ponds. In the first case, it is also common to incorporate single-effect absorption systems for cooling production. The use of thermal desalination processes is also found in many proposals based on solar ORC. In this case, the usual configuration implies the cycle’s cooling by the own desalination process. This option is also common in systems based on the supercritical CO₂ power cycle where MED technology is usually selected. Designs proposals are reviewed and assessed to point out design recommendations. Full article

(This article belongs to the Special Issue Desalination Processes by Renewable Energy (RE))

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17 pages, 8863 KiB

Open AccessArticle

Deionized Water Electrochemical Machining Hybridized with Alumina Powder Polishing for Microcavity of M-333 Mold Steel

by Albert Wen-Jeng Hsue and Zih-Yuan Huang

Processes 2022, 10(1), 152; https://doi.org/10.3390/pr10010152 - 13 Jan 2022

Cited by 2 | Viewed by 1552

Abstract

An electrochemical machining (ECM) process for microcavity fabrication with deionized water (DI-water) and an ECM polishing hybrid with alumina powder of 1.0 μm grains on a single micro-EDM machine are proposed. The process adopts tungsten carbide as tool electrode and M-333 tool steel [...] Read more.

An electrochemical machining (ECM) process for microcavity fabrication with deionized water (DI-water) and an ECM polishing hybrid with alumina powder of 1.0 μm grains on a single micro-EDM machine are proposed. The process adopts tungsten carbide as tool electrode and M-333 tool steel as the mold material. It reveals that employing the 30 μm/min feed rate with 50 mA and 0.2 ms of pulse-width is suitable for DI-water electrochemical machining. The DI-water ECM process can achieve an excellent surface roughness at Ra 0.169 µm on a semispherical round cavity. Combining the ECM with hybrid polishing with the alumina powder can achieve a better profile for a much deeper cavity than pure electrolytic discharge machining. The hybrid ECM polishing can efficiently finish a micro square insert of 0.6 mm length at 64 μm depth. Such ECM milling can achieve an S-shaped microchannel of radius 1.0 mm and a slot of 1.0 × 0.5 mm² with 110 μm depth, demonstrating its feasibility and the surface integrity with accurate profile and roughness of Ra 0.227 μm. This study provides a cost-effective scheme for micro mold fabrication with a conventional micro-EDM machine tool and an intuitive and convenient optional process. However, some micro-electrical discharges occurred due to the breakdown of insulation, which creates micro craters on the surface of the parts. Full article

(This article belongs to the Special Issue New Frontiers in Magnetic Polishing and Electrochemical Technology)

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12 pages, 2972 KiB

Open AccessArticle

Influence of Post- and Pre-Acid Treatment during Hydrothermal Carbonization of Sewage Sludge on P-Transformation and the Characteristics of Hydrochar

by Vicky Shettigondahalli Ekanthalu, Satyanarayana Narra, Tommy Ender, Edward Antwi and Michael Nelles

Processes 2022, 10(1), 151; https://doi.org/10.3390/pr10010151 - 12 Jan 2022

Cited by 10 | Viewed by 2322

Abstract

Phosphorus (P) recovery from alternative P-rich residues is essential to meet the growing demands of food production globally. Despite sewage sludge being a potential source for P, its direct application on agricultural land is controversial because of the obvious concerns related to heavy [...] Read more.

Phosphorus (P) recovery from alternative P-rich residues is essential to meet the growing demands of food production globally. Despite sewage sludge being a potential source for P, its direct application on agricultural land is controversial because of the obvious concerns related to heavy metals and organic pollutants. Further, most of the available P recovery and sludge management technologies are cost-intensive as they require mandatory dewatering of sewage sludge. In this regard, hydrothermal carbonization (HTC) has gained great attention as a promising process to effectively treat the wet sewage sludge without it having to be dewatered, and it simultaneously enables the recovery of P. This study was conducted to analyse and compare the influence of acid (H₂SO₄) addition during and after HTC of sewage sludge on P leaching and the characteristics of hydrochar. The obtained results suggested that despite using the same amount of H₂SO₄, P leaching from solid to liquid phase was significantly higher when acid was used after the HTC of sewage sludge in comparison with acid utilization during the HTC process. After HTC, the reduction in acid-buffering capacity of sewage sludge and increase in solubility of phosphate precipitating metal ions had a greater influence on the mobilization of P from solid to liquid phase. In contrast, utilization of H₂SO₄ in different process conditions did not have a great influence on proximate analysis results and calorific value of consequently produced hydrochar. Full article

(This article belongs to the Special Issue Emerging Technologies for Water and Wastewater Treatment)

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16 pages, 3996 KiB

Open AccessArticle

Modified Activated Carbon for Copper Ion Removal from Aqueous Solution

by Wei-Sheng Chen, Yun-Chung Chen and Cheng-Han Lee

Processes 2022, 10(1), 150; https://doi.org/10.3390/pr10010150 - 12 Jan 2022

Cited by 28 | Viewed by 3529

Abstract

Because of increasing environmental awareness, it is becoming more important to remove harmful elements from water solutions. This study used activated carbon (AC) derived from waste wood-based panels as the base material, oxidized with nitric acid (OAC), and grafted with iminodiacetic acid (IDA-OAC) [...] Read more.

Because of increasing environmental awareness, it is becoming more important to remove harmful elements from water solutions. This study used activated carbon (AC) derived from waste wood-based panels as the base material, oxidized with nitric acid (OAC), and grafted with iminodiacetic acid (IDA-OAC) to improve the adsorption capacity and affinity for metals. The characterization of AC, OAC, and IDA-OAC was conducted via FTIR, SEM, N₂ adsorption and desorption analysis, elemental analysis, Boehm titration, and point of zero charge (PZC). The instrument studies proved the modified increasing of the functional groups of the adsorbents. Moreover, batch and column experiments were conducted to evaluate the ability of the three adsorbents to remove copper ions from aqueous solution. In batch sorption, IDA-OAC had the highest adsorption capacity (84.51 mg/g) compared to OAC (54.74 mg/g) and AC (24.86 mg/g) at pH 5. The breakthrough point (C_t/C_i = 0.05) of copper ions for IDA-OAC occurred much later than AC in the column experiment (AC = 19 BV, IDA-OAC = 52 BV). The Langmuir isotherm and pseudo-second-model kinetics modeling could better fit with the data obtained from the batch sorption of AC, OAC, and IDA-OAC. The significant capacity and reusability of IDA-OAC displayed high applicability for water treatment. Full article

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

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