Processes

16 pages, 5810 KiB

Open AccessArticle

Analysis of Dynamic Characteristics and Control Strategies of a Solvent Dehydration Distillation Column in a Purified Terephthalic Acid Plant

by Xiuhui Huang, Jun Wang and Zeqiu Li

Processes 2020, 8(1), 125; https://doi.org/10.3390/pr8010125 - 19 Jan 2020

Cited by 2 | Viewed by 5294

Abstract

In this study, a solvent dehydration column of purified terephthalic acid (PTA) plant was used as the research object. Based on a dynamic model of the solvent dehydration column, a dynamic sensitivity analysis of the key parameters was carried out using Aspen Dynamics. [...] Read more.

In this study, a solvent dehydration column of purified terephthalic acid (PTA) plant was used as the research object. Based on a dynamic model of the solvent dehydration column, a dynamic sensitivity analysis of the key parameters was carried out using Aspen Dynamics. After the dynamic model reached stability, the reflux rate, methyl acetate concentration, and reflux temperature of the solvent dehydration column were adjusted and the changes of the key separation indexes under the corresponding disturbance were analyzed. According to the analysis results, a sensitive plate temperature controller was added to carry out the dynamic sensitivity analysis. In addition, the acetic acid (HAc) concentration of the bottom of the column was found to be unstable in the dynamic sensitivity analysis. Considering the HAc concentration controller of the column bottom, two control strategies were designed. By analyzing the dynamic response of the feed flow disturbance under different control strategies, a more suitable control strategy under different conditions was obtained. From this, a reasonable method could be derived to design the control strategy, thereby providing a theoretical basis for further real-time optimization and advanced control of solvent dehydration in a PTA plant. Full article

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

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23 pages, 4240 KiB

Open AccessArticle

Screening of Amino Acids and Surfactant as Hydrate Promoter for CO₂ Capture from Flue Gas

by Jyoti Shanker Pandey, Yousef Jouljamal Daas and Nicolas von Solms

Processes 2020, 8(1), 124; https://doi.org/10.3390/pr8010124 - 19 Jan 2020

Cited by 35 | Viewed by 4691

Abstract

In this study, the kinetics of flue gas hydrate formation in bulk water in the presence of selected amino acids and surfactants are investigated. Four amino acids (3000 ppm) are selected based on different hydropathy index. Constant-ramping and isothermal experiments at 120 bar [...] Read more.

In this study, the kinetics of flue gas hydrate formation in bulk water in the presence of selected amino acids and surfactants are investigated. Four amino acids (3000 ppm) are selected based on different hydropathy index. Constant-ramping and isothermal experiments at 120 bar pressure and 1 °C temperature are carried out to compare their hydrate promotion capabilities with surfactant sodium dodecyl sulfate (SDS) (500–3000 ppm) and water. Based on experimental results, we report the correlation between hydrate promotion capability of amino acids and their hydrophobicity. Hydrophobic amino acids show stronger flue gas hydrate promotion capability than water and hydrophilic amino acids. We discuss the controlling mechanisms to differentiate between promoters and inhibitors’ roles among the amino acids. Between 2000–3000 ppm concentrations, hydrophobic amino acids have near similar promotion capabilities as SDS. This research highlights the potential use of amino acids as promoters or inhibitors for various applications. Full article

(This article belongs to the Special Issue Analysis and Experimental Study on Natural Gas Hydrate Exploitation Processes)

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15 pages, 2257 KiB

Open AccessArticle

Multimode Operating Performance Visualization and Nonoptimal Cause Identification

by Yuhui Ying, Zhi Li, Minglei Yang and Wenli Du

Processes 2020, 8(1), 123; https://doi.org/10.3390/pr8010123 - 19 Jan 2020

Cited by 6 | Viewed by 2544

Abstract

In the traditional performance assessment method, different modes of data are classified mainly by expert knowledge. Thus, human interference is highly probable. The traditional method is also incapable of distinguishing transition data from steady-state data, which reduces the accuracy of the monitor model. [...] Read more.

In the traditional performance assessment method, different modes of data are classified mainly by expert knowledge. Thus, human interference is highly probable. The traditional method is also incapable of distinguishing transition data from steady-state data, which reduces the accuracy of the monitor model. To solve these problems, this paper proposes a method of multimode operating performance visualization and nonoptimal cause identification. First, multimode data identification is realized by subtractive clustering algorithm (SCA), which can reduce human influence and eliminate transition data. Then, the multi-space principal component analysis (MsPCA) is used to characterize the independent characteristics of different datasets, which enhances the robustness of the model with respect to the performance of independent variables. Furthermore, a self-organizing map (SOM) is used to train these characteristics and map them into a two-dimensional plane, by which the visualization of the process monitor is realized. For the online assessment, the operating performance of the current process is evaluated according to the projection position of the data on the visual model. Then, the cause of the nonoptimal performance is identified. Finally, the Tennessee Eastman (TE) process is used to verify the effectiveness of the proposed method. Full article

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

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21 pages, 11290 KiB

Open AccessArticle

Numerical Study on the Influence of Inlet Guide Vanes on the Internal Flow Characteristics of Centrifugal Pump

by Peifeng Lin, Yongzheng Li, Wenbin Xu, Hui Chen and Zuchao Zhu

Processes 2020, 8(1), 122; https://doi.org/10.3390/pr8010122 - 17 Jan 2020

Cited by 14 | Viewed by 3929

Abstract

In order to make the centrifugal pump run efficiently and stably under various working conditions, the influences of the incoming vortex flow in the inlet pipe on the main flow in the impeller is studied numerically, based on the

k - ω

SST [...] Read more.

In order to make the centrifugal pump run efficiently and stably under various working conditions, the influences of the incoming vortex flow in the inlet pipe on the main flow in the impeller is studied numerically, based on the

k - ω

SST turbulence model. Some guide vanes with different offset angle were added to change the statistical characteristic of the internal flow in the inlet pipe of the centrifugal pump. Both contour distributions of internal flow and statistical results of external performance are obtained and analyzed. The results show that the existence of vanes can divide the large vortex because of the reversed flow from the rotating impeller at low flow rate conditions into small vortices, which are easier to dissipate, make the velocity and pressure distribution more uniform, improve the stability of the flow in the impeller, reduce the hydraulic loss, and improve the hydraulic performance of the pump. The pump with vanes of offset angle 25° has a small pressure pulsation amplitude at each monitoring point. Comparing with the performance of the original pump, the head increased by around 2% and efficiency increased by around 2.5% of the pump with vanes of offset angle 25°. Full article

(This article belongs to the Collection Modeling, Simulation and Computation on Dynamics of Complex Fluids)

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29 pages, 1072 KiB

Open AccessFeature PaperReview

Modeling and Exploiting Microbial Temperature Response

by Philipp Noll, Lars Lilge, Rudolf Hausmann and Marius Henkel

Processes 2020, 8(1), 121; https://doi.org/10.3390/pr8010121 - 17 Jan 2020

Cited by 25 | Viewed by 9775

Abstract

Temperature is an important parameter in bioprocesses, influencing the structure and functionality of almost every biomolecule, as well as affecting metabolic reaction rates. In industrial biotechnology, the temperature is usually tightly controlled at an optimum value. Smart variation of the temperature to optimize [...] Read more.

Temperature is an important parameter in bioprocesses, influencing the structure and functionality of almost every biomolecule, as well as affecting metabolic reaction rates. In industrial biotechnology, the temperature is usually tightly controlled at an optimum value. Smart variation of the temperature to optimize the performance of a bioprocess brings about multiple complex and interconnected metabolic changes and is so far only rarely applied. Mathematical descriptions and models facilitate a reduction in complexity, as well as an understanding, of these interconnections. Starting in the 19th century with the “primal” temperature model of Svante Arrhenius, a variety of models have evolved over time to describe growth and enzymatic reaction rates as functions of temperature. Data-driven empirical approaches, as well as complex mechanistic models based on thermodynamic knowledge of biomolecular behavior at different temperatures, have been developed. Even though underlying biological mechanisms and mathematical models have been well-described, temperature as a control variable is only scarcely applied in bioprocess engineering, and as a conclusion, an exploitation strategy merging both in context has not yet been established. In this review, the most important models for physiological, biochemical, and physical properties governed by temperature are presented and discussed, along with application perspectives. As such, this review provides a toolset for future exploitation perspectives of temperature in bioprocess engineering. Full article

(This article belongs to the Special Issue Bioprocess Monitoring and Control)

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11 pages, 3170 KiB

Open AccessArticle

Characteristics of Low-Temperature Polyvinyl Chloride Carbonization by Catalytic CuAl Layered Double Hydroxide

by Erwei Pang, Weijun Liu, Shuhua Zhang, Nengshuo Fu and Zhongxun Tian

Processes 2020, 8(1), 120; https://doi.org/10.3390/pr8010120 - 17 Jan 2020

Cited by 5 | Viewed by 4613

Abstract

A good way to make carbon materials was presented in low-temperature polyvinyl chloride (PVC) carbonization by catalysis. The process of low-temperature PVC carbonization by CuAl-layered double hydroxide (CuAl-LDH) was investigated by thermogravimetric analysis (TGA) and tubular furnace. The results show that CuAl-LDH accounting [...] Read more.

A good way to make carbon materials was presented in low-temperature polyvinyl chloride (PVC) carbonization by catalysis. The process of low-temperature PVC carbonization by CuAl-layered double hydroxide (CuAl-LDH) was investigated by thermogravimetric analysis (TGA) and tubular furnace. The results show that CuAl-LDH accounting for 5% of PVC mass enabled acceleration of the dehydrochlorination in PVC as soon as possible and maximized the yield of the PVC carbonized product. The vacuum with 0.08 MPa, 20 °C/min heating rate and 90 min carbonized maintenance time were optimal for PVC carbonization. Moreover, the best morphology and yield of the carbonized product was provided at a carbonization temperature of 300 °C. Full article

(This article belongs to the Special Issue Processes for Bioenergy and Resources Recovery from Biowaste)

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12 pages, 1358 KiB

Open AccessArticle

Energy and Material Flows and Carbon Footprint Assessment Concerning the Production of HMF and Furfural from a Cellulosic Biomass

by Hannes Schöppe, Peter Kleine-Möllhoff and Rolf Epple

Processes 2020, 8(1), 119; https://doi.org/10.3390/pr8010119 - 17 Jan 2020

Cited by 21 | Viewed by 5498

Abstract

5-hydroxymethyl-furfural (HMF) and furfural are interesting as potential platform chemicals for a bio-based chemical production economy. Within the scope of this work, the process routes under technical development for the production of these platform chemicals were investigated. For two selected processes, the material [...] Read more.

5-hydroxymethyl-furfural (HMF) and furfural are interesting as potential platform chemicals for a bio-based chemical production economy. Within the scope of this work, the process routes under technical development for the production of these platform chemicals were investigated. For two selected processes, the material and energy flows, as well as the carbon footprint, were examined in detail. The possible production process optimizations, further development potentials, and the research demand against the background of the reduction of the primary energy expenditure were worked out. Full article

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

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11 pages, 1142 KiB

Open AccessArticle

Polyetherimide-Montmorillonite Nano-Hybrid Composite Membranes: CO₂ Permeance Study via Theoretical Models

by Asif Jamil, Oh Pei Ching, Muhammad Naqvi, Hafiza Aroosa Aslam Khan and Salman Raza Naqvi

Processes 2020, 8(1), 118; https://doi.org/10.3390/pr8010118 - 17 Jan 2020

Cited by 2 | Viewed by 2668

Abstract

The incorporation of aminolauric acid modified montmorillonite (f-MMT) in polyetherimide (PEI) has been implemented to develop hollow fibre nano-hybrid composite membranes (NHCMs) with improved gas separation characteristics. The aforementioned characteristics are caused by enhanced f-MMT spatial dispersion and interfacial interactions [...] Read more.

The incorporation of aminolauric acid modified montmorillonite (f-MMT) in polyetherimide (PEI) has been implemented to develop hollow fibre nano-hybrid composite membranes (NHCMs) with improved gas separation characteristics. The aforementioned characteristics are caused by enhanced f-MMT spatial dispersion and interfacial interactions with PEI matrix. In this study, existing gas permeation models such as, Nielsen, Cussler, Yang–Cussler, Lape–Cussler and Bharadwaj were adopted to estimate the dispersion state of f-MMT and to predict the CO₂ permeance in developed NHCMs. It was found out that the average aspect ratio estimated was 53, with 3 numbers of stacks per unit tactoid, which showed that the intercalation f-MMT morphology is the dominating dispersion state of filler in PEI matrix. Moreover, it was observed that Bharadwaj model showed the least average absolute relative error (%AARE) values till 3 wt. % f-MMT loading in the range of ±10 for a pressure range of 2 to 10 bar. Hence, Bharadwaj was the best fit model for the experimental data compared to other models, as it considers the platelets orientation. Full article

(This article belongs to the Special Issue Nano-Hybrid Composite Membranes)

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12 pages, 1847 KiB

Open AccessArticle

Correlation between Antibacterial Activity and Free-Radical Scavenging: In-Vitro Evaluation of Polar/Non-Polar Extracts from 25 Plants

by Mahmoud Rayan, Baheer Abu-Farich, Walid Basha, Anwar Rayan and Saleh Abu-Lafi

Processes 2020, 8(1), 117; https://doi.org/10.3390/pr8010117 - 17 Jan 2020

Cited by 14 | Viewed by 4715

Abstract

Objectives: The current study aimed to measure the antioxidant and antibacterial activities of 25 wild Palestinian edible plants, which were subjected to extraction by polar and non-polar solvents. Correlations between free radical scavenging activity and antibacterial activity of the extracts were assessed for [...] Read more.

Objectives: The current study aimed to measure the antioxidant and antibacterial activities of 25 wild Palestinian edible plants, which were subjected to extraction by polar and non-polar solvents. Correlations between free radical scavenging activity and antibacterial activity of the extracts were assessed for both polar and non-polar fractions. Materials: Twenty-five wild edible plant species that are frequently consumed by people in Palestine (mainly in a rural area) were examined. Among them, 10 plant species were among those with the highest mean cultural importance values, according to an ethnobotanical survey that was conducted in the West Bank, Palestine, a few years ago. Method: The protocol of the DPPH assay for testing free-radical scavenging was utilized for determining EC₅₀ values, while microdilution tests were conducted to determine the 50% inhibitory concentration (IC₅₀) of the extracts for the microorganism Staphylococcus mutans. Results and Discussion: Eight extracts (non-polar fractions) were found to possess an antibacterial IC₅₀ of less than 20 ppm, such as Foeniculum vulgare, Salvia palaestinafruticose, Micromeria fruticose, Trigonella foenum-graecum, Cichorium pumilum jacq, Salvia hierosolymitana boiss, Ruta chalepensis, and Chrysanthemum coronarium. The polar fractions possess higher antioxidant activity, while non-polar fraction possess higher antibacterial activity. Looking at all the results together can deceive and lead to the conclusion that there is no correlation between antibacterial activity against S. mutans and free radical scavenging (R² equals 0.0538). However, in-depth analysis revealed that non-polar plant extracts with an EC₅₀ of free radical scavenging ≤100 ppm have a four-fold order of enrichment toward more activity against S. mutans. These findings are of high importance for screening projects. A four-fold order of enrichment could save plenty of time and many in screening projects. The antibacterial active extracts marked by low-medium free radical scavenging might act through a mechanism of action other than that of highly active, free radical scavenging extracts. Conclusion: The screening of antioxidant and antimicrobial activity performed on 25 selected wild plant extracts revealed a satisfactory free radical scavenging and antimicrobial potential that could be of value in the management of oxidative stress. Further studies are recommended to explore novel and highly active natural antibacterial products. Full article

(This article belongs to the Special Issue Extraction, Characterization and Pharmacology of Natural Products)

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12 pages, 5879 KiB

Open AccessArticle

Controllability Comparison of the Four-Product Petlyuk Dividing Wall Distillation Column Using Temperature Control Schemes

by Xing Qian, Rui Liu, Kejin Huang, Haisheng Chen, Yang Yuan, Liang Zhang and Shaofeng Wang

Processes 2020, 8(1), 116; https://doi.org/10.3390/pr8010116 - 16 Jan 2020

Cited by 6 | Viewed by 3248

Abstract

An effective process intensification strategy based on dividing walls shows promising energy-saving results for distillation processes. The three-product Petlyuk dividing wall distillation columns (DWDCs) are able to save approximately 30% energy in comparison with the traditional distillation columns. Furthermore, the four-product extended Petlyuk [...] Read more.

An effective process intensification strategy based on dividing walls shows promising energy-saving results for distillation processes. The three-product Petlyuk dividing wall distillation columns (DWDCs) are able to save approximately 30% energy in comparison with the traditional distillation columns. Furthermore, the four-product extended Petlyuk DWDC reduces about 50% of operation costs than conventional distillation sequences. Although researchers have extensively studied control schemes for the three-product Petlyuk DWDC, relatively little work has been done on the four-product extended Petlyuk DWDC. This paper studies feasible temperature control schemes containing temperature control scheme (TC), simplified temperature difference control scheme (STDC), and simplified double temperature difference control scheme (SDTDC) for the four-product extended Petlyuk DWDC. STDC and SDTDC are introduced so as to improve the dynamic performances with simple control schemes. All three control schemes are tested against a series of feed compositions and feed rate disturbances. Dynamic performances prove that the proposed STDC and SDTDC schemes are better at handling the inserted feed disturbances. These are very encouraging results for industrialization of the four-product extended Petlyuk DWDC in the future. Full article

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

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20 pages, 3249 KiB

Open AccessFeature PaperReview

Plasmonic-Active Nanostructured Thin Films

by Jay K. Bhattarai, Md Helal Uddin Maruf and Keith J. Stine

Processes 2020, 8(1), 115; https://doi.org/10.3390/pr8010115 - 16 Jan 2020

Cited by 17 | Viewed by 9864

Abstract

Plasmonic-active nanomaterials are of high interest to scientists because of their expanding applications in the field for medicine and energy. Chemical and biological sensors based on plasmonic nanomaterials are well-established and commercially available, but the role of plasmonic nanomaterials on photothermal therapeutics, solar [...] Read more.

Plasmonic-active nanomaterials are of high interest to scientists because of their expanding applications in the field for medicine and energy. Chemical and biological sensors based on plasmonic nanomaterials are well-established and commercially available, but the role of plasmonic nanomaterials on photothermal therapeutics, solar cells, super-resolution imaging, organic synthesis, etc. is still emerging. The effectiveness of the plasmonic materials on these technologies depends on their stability and sensitivity. Preparing plasmonics-active nanostructured thin films (PANTFs) on a solid substrate improves their physical stability. More importantly, the surface plasmons of thin film and that of nanostructures can couple in PANTFs enhancing the sensitivity. A PANTF can be used as a transducer for any of the three plasmonic-based sensing techniques, namely, the propagating surface plasmon, localized surface plasmon resonance, and surface-enhanced Raman spectroscopy-based sensing techniques. Additionally, continuous nanostructured metal films have an advantage for implementing electrical controls such as simultaneous sensing using both plasmonic and electrochemical techniques. Although research and development on PANTFs have been rapidly advancing, very few reviews on synthetic methods have been published. In this review, we provide some fundamental and practical aspects of plasmonics along with the recent advances in PANTFs synthesis, focusing on the advantages and shortcomings of the fabrication techniques. We also provide an overview of different types of PANTFs and their sensitivity for biosensing. Full article

(This article belongs to the Special Issue Materials Processing for Production of Nanostructured Thin Films)

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18 pages, 1395 KiB

Open AccessArticle

Research on Green Power Dispatching Based on an Emergy-Based Life Cycle Assessment

by Tao Li, Yi Miao Song, Ang Li, Jing Shen, Chao Liang and Ming Gao

Processes 2020, 8(1), 114; https://doi.org/10.3390/pr8010114 - 16 Jan 2020

Cited by 8 | Viewed by 2889

Abstract

Environmental protection pressures and green energy strategies have created major challenges for a cleaner production of China’s coal-fired power generation. Although China’s electric power dispatching department has tried to prioritize clean energy, the current dispatching models lack environmental indicators related to coal-fired power [...] Read more.

Environmental protection pressures and green energy strategies have created major challenges for a cleaner production of China’s coal-fired power generation. Although China’s electric power dispatching department has tried to prioritize clean energy, the current dispatching models lack environmental indicators related to coal-fired power generation. The main purpose of this paper is to provide a comprehensive environmental indicator for the cleanliness evaluation of coal-fired power plants. In this paper, the (Emergy-based Life Cycle Assessment) Em-LCA method is used to measure and analyze environmental related resource consumption, socio-economic investment, and emissions in the whole life cycle of coal-fired power plants. At the same time, based on the above three environmental impacts in the whole life cycle, this paper constructs the (Em-LCA based Cleaner Production Comprehensive Evaluation) ECPCE index to guide a green dispatching plan. By comparing the calculation results of the index, this paper finds that there are differences in the environmental advantages of different generating units in green dispatching, which are closely related to the process management of coal-fired power plants in production and the environment. Full article

(This article belongs to the Section Advanced Digital and Other Processes)

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13 pages, 3288 KiB

Open AccessArticle

The Potential Antibacterial and Antifungal Activities of Wood Treated with Withania somnifera Fruit Extract, and the Phenolic, Caffeine, and Flavonoid Composition of the Extract According to HPLC

by Mervat EL-Hefny, Mohamed Z. M. Salem, Said I. Behiry and Hayssam M. Ali

Processes 2020, 8(1), 113; https://doi.org/10.3390/pr8010113 - 16 Jan 2020

Cited by 40 | Viewed by 6273

Abstract

In the present study, Melia azedarach wood blocks treated with different acetone extract concentrations from Withania somnifera fruits are assessed for their antibacterial and anti-fungal activities. Wood blocks of M. azedarach treated with W. somnifera fruit extract at concentrations of 0, 1, 2, [...] Read more.

In the present study, Melia azedarach wood blocks treated with different acetone extract concentrations from Withania somnifera fruits are assessed for their antibacterial and anti-fungal activities. Wood blocks of M. azedarach treated with W. somnifera fruit extract at concentrations of 0, 1, 2, and 3% are evaluated for in vitro antimicrobial activity against five genbank accessioned bacterial strains—Agrobacterium tumefaciens, Dickeya solani, Erwinia amylovora, Pseudomonas cichorii, and Serratia pylumthica—and two fungi, namely, Fusarium culmorum and Rhizoctonia solani. Through HPLC analysis we find that the most abundant quantified phenolic and flavonoid compounds of acetone extract (mg/100 g) are salicylic acid (9.49), vanillic acid (4.78), rutin (4702.58), and myricetin (1386.62). Wood treated with the extract at 2% and 3% show no growth of A. tumefaciens, E. amylovora, and P. cichorii. Use of the extract at 3% causes inhibition of fungal mycelia of F. culmorum and R. solani by 84.07% and 67.03%, respectively. In conclusion, potent antifungal and antibacterial activity against plant pathogens is found when an acetone extract of W. somnifera fruits is applied to wood samples. Full article

(This article belongs to the Special Issue Green Separation and Extraction Processes)

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9 pages, 2113 KiB

Open AccessArticle

Co-Firing of Sawdust and Liquid Petroleum Gas in the Application of a Modified Rocket Stove

by Paisan Comsawang, Suwat Nanetoe and Nitipong Soponpongpipat

Processes 2020, 8(1), 112; https://doi.org/10.3390/pr8010112 - 15 Jan 2020

Cited by 3 | Viewed by 4531

Abstract

The heating rate, firepower, and thermal efficiency of a modified rocket stove using sawdust and liquid petroleum gas (LPG) as co-firing fuel were investigated. Three modified rocket stoves with a height of 400 mm and outside diameters of 225, 385, and 550 mm [...] Read more.

The heating rate, firepower, and thermal efficiency of a modified rocket stove using sawdust and liquid petroleum gas (LPG) as co-firing fuel were investigated. Three modified rocket stoves with a height of 400 mm and outside diameters of 225, 385, and 550 mm were tested. It was found that there was an insignificant difference in heating rate and firepower when stoves were tested without co-firing with LPG. In this case, the stove heating rate was in the range of 1.49–1.55 °C/min. When LPG was used, the heating rate tended to linearly increase with the increase of LPG flow rate. The heating rate was in range of 2.42–2.80, 2.63–3.27, and 3.07–4.22 °C/min when LPG consumption rates were 2.38 × 10⁻⁵, 3.33 × 10⁻⁵, and 5.00 × 10⁻⁵ kg/s, respectively. The slight increase of stove heating rate and firepower was seen when the stove diameter was increased from 225 to 385 mm. The increase of stove diameter from 385 to 550 mm resulted in a huge increase of heating rate and firepower. Thermal efficiency of the sawdust stove without LPG decreased from 17.90% to 9.97% when the stove diameter was increased from 225 to 550 mm. For co-firing of sawdust and LPG, the increase of LPG flow rate from 2.38 × 10⁻⁵ to 5 × 10⁻⁵ kg/s caused the linear increase of thermal efficiency from 20.27% to 33.80%, 29.36% to 38.89%, and 25.25% to 36.39% for the stove with diameters of 225, 385, and 550 mm., respectively. Full article

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

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12 pages, 819 KiB

Open AccessArticle

Evaluation of Different Treatment Processes for Landfill Leachate Using Low-Cost Agro-Industrial Materials

by Tawfiq J. H. Banch, Marlia M. Hanafiah, Abbas F. M. Alkarkhi, Salem S. A. Amr and Nurul U. M. Nizam

Processes 2020, 8(1), 111; https://doi.org/10.3390/pr8010111 - 15 Jan 2020

Cited by 24 | Viewed by 4169

Abstract

Leachate is a complex liquid that is often produced from landfills, and it contains hazardous substances that may endanger the surrounding environment if ineffectively treated. In this work, four leachate treatment applications were examined: combined leachate/palm oil mill effluent (POME) (LP), leachate/tannin (LT), [...] Read more.

Leachate is a complex liquid that is often produced from landfills, and it contains hazardous substances that may endanger the surrounding environment if ineffectively treated. In this work, four leachate treatment applications were examined: combined leachate/palm oil mill effluent (POME) (LP), leachate/tannin (LT), pre-(leachate/tannin) followed by post-(leachate/POME) (LT/LP), and pre-(leachate/POME) followed by post-(leachate/tannin) (LP/LT). The aim of this work is to evaluate and compare the performance of these treatment applications in terms of optimizing the physicochemical parameters and removing heavy metals from the leachate. The highest efficiency for the optimization of the most targeted physicochemical parameters and the removal of heavy metals was with the LP/LT process. The results are indicative of three clusters. The first cluster involves raw leachate (cluster 1), the second contains LP and LP/LT (cluster 2), and the third also consists of two treatment applications, namely, LT and LT/LP (cluster 3). The results demonstrate that LP/LT is the most appropriate method for leachate treatment using low-cost agro-industrial materials. Full article

(This article belongs to the Special Issue Wastewater Treatment Processes)

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13 pages, 6462 KiB

Open AccessArticle

Optimization Design and Analysis of Polymer High Efficiency Mixer in Offshore Oil Field

by Zheng Shu, Shijie Zhu, Jian Zhang, Wensen Zhao and Zhongbin Ye

Processes 2020, 8(1), 110; https://doi.org/10.3390/pr8010110 - 15 Jan 2020

Cited by 3 | Viewed by 2857

Abstract

The degree of polymer-water mixing in high-pressure pipelines on offshore oilfields usually influences the polymer solution’s performance. To realize efficient mixing of the polymer mother liquor with dilution water in the high-pressure pipeline, a high-efficiency mixer is designed and optimized. The designed mixer [...] Read more.

The degree of polymer-water mixing in high-pressure pipelines on offshore oilfields usually influences the polymer solution’s performance. To realize efficient mixing of the polymer mother liquor with dilution water in the high-pressure pipeline, a high-efficiency mixer is designed and optimized. The designed mixer consists of four parts: a T-shaped pipe as the main body, an inlet flow-splitting plate, a stainless-steel flow-guiding tube, and an outlet flow-splitting plate. Mathematical models are built by using computational fluid dynamics (CFD) and the mixing effects are compared by using Fluent. The research results show that compared with conventional T-shaped mixers, the designed high-efficiency mixer has better mixing performance and increases the mixing rate to 80%. To optimize the mixing rate, the length of the stainless-steel tube is increased and the tube is perforated to guide the flow. The result shows that boring holes along straight lines around the tube can achieve good optimization effect and increase the mixing rate to 95%. The designed high-efficiency mixer can effectively improve the dissolving efficiency and solve problems in polymer-water mixing in the high-pressure pipeline. Full article

(This article belongs to the Section Advanced Digital and Other Processes)

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17 pages, 3815 KiB

Open AccessArticle

Short-Term Wind Power Prediction Based on Improved Grey Wolf Optimization Algorithm for Extreme Learning Machine

by Jiale Ding, Guochu Chen and Kuo Yuan

Processes 2020, 8(1), 109; https://doi.org/10.3390/pr8010109 - 15 Jan 2020

Cited by 33 | Viewed by 3136

Abstract

In order to improve the accuracy of wind power prediction and ensure the effective utilization of wind energy, a short-term wind power prediction model based on variational mode decomposition (VMD) and an extreme learning machine (ELM) optimized by an improved grey wolf optimization [...] Read more.

In order to improve the accuracy of wind power prediction and ensure the effective utilization of wind energy, a short-term wind power prediction model based on variational mode decomposition (VMD) and an extreme learning machine (ELM) optimized by an improved grey wolf optimization (GWO) algorithm is proposed. The original wind power sequence is decomposed into series of modal components with different center frequencies by the VMD method and some new sequences are obtained by phase space reconstruction (PSR). Then, the ELM model is established for different new time series, and the improved GWO algorithm is used to optimize its parameters. Finally, the output results are weighted and merged as the final predicted value of wind power. The root-mean-square error (RMSE), mean absolute error (MAE), and mean absolute percentage error (MAPE) of the proposed VMD-improved GWO-ELM prediction model in the paper are 5.9113%, 4.6219%, and 13.01% respectively, which are better than these of ELM, back propagation (BP), and the improved GWO-ELM model. The simulation results show that the proposed model has higher prediction accuracy than other models in short-term wind power prediction. Full article

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

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14 pages, 1996 KiB

Open AccessArticle

Non-Linear Sliding Mode Controller for Photovoltaic Panels with Maximum Power Point Tracking

by Hina Gohar Ali, Ramon Vilanova Arbos, Jorge Herrera, Andrés Tobón and Julián Peláez-Restrepo

Processes 2020, 8(1), 108; https://doi.org/10.3390/pr8010108 - 14 Jan 2020

Cited by 33 | Viewed by 5186

Abstract

In this paper, nonlinear sliding mode control (SMC) techniques formulated for extracting maximum power from a solar photovoltaic (PV) system under variable environmental conditions employing the perturb and observe (P and O) maximum power point tracking (MPPT) technique are discussed. The PV system [...] Read more.

In this paper, nonlinear sliding mode control (SMC) techniques formulated for extracting maximum power from a solar photovoltaic (PV) system under variable environmental conditions employing the perturb and observe (P and O) maximum power point tracking (MPPT) technique are discussed. The PV system is connected with load through the boost converter. A mathematical model of the boost converter is derived first, and based on the derived model, a SMC is formulated to control the gating pulses of the boost converter switch. The closed loop system stability is verified through the Lyapunov stability theorem. The presented control scheme along with the solar PV system is simulated in MATLAB (matric laboratory) (SMC controller and PWM (Pulse Width Modulation) part) and PSIM (Power electronics simulations) (solar PV and MPPT algorithm) environments using the Simcoupler tool. The simulation results of the proposed controller (SMC) are compared with the classical proportional integral derivative (PID) control scheme, keeping system parameters and environmental parameters the same. Full article

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

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22 pages, 3691 KiB

Open AccessArticle

A Two-Stage Optimal Scheduling Model of Microgrid Based on Chance-Constrained Programming in Spot Markets

by Jiayu Li, Caixia Tan, Zhongrui Ren, Jiacheng Yang, Xue Yu and Zhongfu Tan

Processes 2020, 8(1), 107; https://doi.org/10.3390/pr8010107 - 14 Jan 2020

Cited by 5 | Viewed by 2793

Abstract

Aimed at the coordination control problem of each unit caused by microgrid participation in the spot market and considering the randomness of wind and solar output and the uncertainty of spot market prices, a day-ahead real-time two-stage optimal scheduling model for microgrid was [...] Read more.

Aimed at the coordination control problem of each unit caused by microgrid participation in the spot market and considering the randomness of wind and solar output and the uncertainty of spot market prices, a day-ahead real-time two-stage optimal scheduling model for microgrid was established by using the chance-constrained programming theory. On this basis, an improved particle swarm optimization (PSO) algorithm based on stochastic simulation technology was used to solve the problem and the effect of demand side management and confidence level on scheduling results is discussed. The example results verified the correctness and effectiveness of the proposed model, which can provide a theoretical basis in terms of reasonably coordinating the output of each unit in the microgrid in the spot market. Full article

(This article belongs to the Special Issue Advances in Sustainable Supply Chains)

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12 pages, 1609 KiB

Open AccessArticle

Physicochemical Properties of Guava Snacks as Affected by Drying Technology

by Yuri M. Leiton-Ramírez, Alfredo Ayala-Aponte and Claudia I. Ochoa-Martínez

Processes 2020, 8(1), 106; https://doi.org/10.3390/pr8010106 - 14 Jan 2020

Cited by 17 | Viewed by 6176

Abstract

Guava is widely consumed because of its agro-industrial use, and its antioxidant properties attributed to vitamin C and carotenoids content. However, it has a short shelf life. Guava has been dried by atomization, fluidized bed, lyophilization (FD) and convective drying (CD). CD requires [...] Read more.

Guava is widely consumed because of its agro-industrial use, and its antioxidant properties attributed to vitamin C and carotenoids content. However, it has a short shelf life. Guava has been dried by atomization, fluidized bed, lyophilization (FD) and convective drying (CD). CD requires long operation times and the product characteristics are not desirable. In contrast, FD produces high quality products, but requires long processing times, high energy consumption and high operation costs. As an alternative, the Refractance Window^® (RW) drying is relatively simple and cheap technique. The objective of this study was to compare the effect of CD, FD and RW techniques, on the moisture content, water activity, color, porosity, volume change, vitamin C and carotenoids content in guava samples. The samples dried by RW required less time to reduce the moisture content and exhibited smaller changes in color than CD or FD. There were greater losses of carotenoids and vitamin C when drying by CD whereas RW had similar losses than FD. Lyophilized products exhibited minor change in volume and greater porosity. RW results in better retention of properties, compared with other drying techniques. Based on this, RW is a promising technique for the development of guava snacks. Full article

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

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16 pages, 2957 KiB

Open AccessArticle

A Dynamic Active Safe Semi-Supervised Learning Framework for Fault Identification in Labeled Expensive Chemical Processes

by Xuqing Jia, Wende Tian, Chuankun Li, Xia Yang, Zhongjun Luo and Hui Wang

Processes 2020, 8(1), 105; https://doi.org/10.3390/pr8010105 - 13 Jan 2020

Cited by 8 | Viewed by 3454

Abstract

A novel active semi-supervised learning framework using unlabeled data is proposed for fault identification in labeled expensive chemical processes. A principal component analysis (PCA) feature selection strategy is first given to calculate the weight of the variables. Secondly, the identification model is trained [...] Read more.

A novel active semi-supervised learning framework using unlabeled data is proposed for fault identification in labeled expensive chemical processes. A principal component analysis (PCA) feature selection strategy is first given to calculate the weight of the variables. Secondly, the identification model is trained based on the obtained key process variables. Thirdly, the pseudo label confidence of identification model is dynamically optimized with an historical, current, and future pseudo label confidence mean. To increase the upper limit of the identification model that is self-learning with high entropy process data, active learning is used to identify process data and diagnosis fault causes by ontology. Finally, a PCA-dynamic active safe semi-supervised support vector machine (PCA-DAS4VM) for fault identification in labeled expensive chemical processes is built. The application in the Tennessee Eastman (TE) process shows that this hybrid technology is able to: (i) eliminate chemical process noise and redundant process variables simultaneously, (ii) combine historical pseudo label confidence with future pseudo label confidence to improve the identification accuracy of abnormal working conditions, (iii) efficiently select and diagnose high entropy unlabeled process data, and (iv) fully utilize unlabeled data to enhance the identification performance. Full article

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

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14 pages, 4461 KiB

Open AccessArticle

Ultrasonically Induced Sulfur-Doped Carbon Nitride/Cobalt Ferrite Nanocomposite for Efficient Sonocatalytic Removal of Organic Dyes

by Surabhi Kamal, Guan-Ting Pan, Siewhui Chong and Thomas Chung-Kuang Yang

Processes 2020, 8(1), 104; https://doi.org/10.3390/pr8010104 - 13 Jan 2020

Cited by 21 | Viewed by 4441

Abstract

The sulfur-doped carbon nitride/cobalt ferrite nanocomposite (SCN/CoFe₂O₄) was prepared via ultrasonication and studied for the sonocatalytic degradation of wastewater organic dye pollutants including methylene blue, rhodamine B, and Congo red. The X-ray photoelectron spectroscopy confirmed the presence and atomic [...] Read more.

The sulfur-doped carbon nitride/cobalt ferrite nanocomposite (SCN/CoFe₂O₄) was prepared via ultrasonication and studied for the sonocatalytic degradation of wastewater organic dye pollutants including methylene blue, rhodamine B, and Congo red. The X-ray photoelectron spectroscopy confirmed the presence and atomic ratios of S, C, N, Co, Fe, and O elements and their corresponding bonds with Co²⁺ and Fe³⁺ cations. The nanocomposite was found to have aggregated nanoparticles on a sheet-like structure. The bandgap energy was estimated to be 1.85 eV. For the sonocatalytic degradation of 25-ppm methylene blue at 20 kHz, 1 W and 50% amplitude, the best operating condition was determined to be 1 g/L of catalyst dosage and 4 vol % of hydrogen peroxide loading. Under this condition, the sonocatalytic removal efficiency was the highest at 96% within a reaction period of 20 min. SCN/CoFe₂O₄ outperformed SCN and CoFe₂O₄ by 2.2 and 6.8 times, respectively. The SCN/CoFe₂O₄ nanocomposite was also found to have good reusability with a drop of only 7% after the fifth cycle. However, the degradation efficiencies were low when tested with rhodamine B and Congo red due to difference in dye sizes, structural compositions, and electric charges. Full article

(This article belongs to the Special Issue Advanced Liquid Waste and Gas Waste Treatment Processes)

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11 pages, 2927 KiB

Open AccessFeature PaperArticle

Hygro-Thermo-Mechanical Responses of Balsa Wood Core Sandwich Composite Beam Exposed to Fire

by Luan TranVan, Vincent Legrand, Pascal Casari, Revathy Sankaran, Pau Loke Show, Aydin Berenjian and Chyi-How Lay

Processes 2020, 8(1), 103; https://doi.org/10.3390/pr8010103 - 13 Jan 2020

Cited by 4 | Viewed by 4794

Abstract

In this study, the hygro–thermo–mechanical responses of balsa core sandwich structured composite was investigated by using experimental, analytical and numerical results. These investigations were performed on two types of specimen conditions: dry and moisture saturation sandwich composite specimens that are composed of E-glass/polyester [...] Read more.

In this study, the hygro–thermo–mechanical responses of balsa core sandwich structured composite was investigated by using experimental, analytical and numerical results. These investigations were performed on two types of specimen conditions: dry and moisture saturation sandwich composite specimens that are composed of E-glass/polyester skins bonded to a balsa core. The wet specimens were immersed in distilled water at 40 °C until saturated with water. The both dry and wet sandwich composite specimens were heated by fire. The mass loss kinetic and the mechanical properties were investigated by using a cone calorimeter following the ISO 5660 standard and three-point bending mechanical test device. Experimental data show that the permeability and fire resistance of the sandwich structure are controlled by two composite skins. Obtained results allow us to understand the Hygro–Thermo–Mechanical Responses of the sandwich structured composite under application conditions. Full article

(This article belongs to the Special Issue Green Technologies: Bridging Conventional Practices and Industry 4.0)

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7 pages, 1178 KiB

Open AccessFeature PaperArticle

The Effects of Lung-Moistening Herbal Medicines on Bleomycin-Induced Pulmonary Fibrosis Mouse Model

by Junmo Ahn, Hyejin Joo, Jihye Park, Jae-Woo Park, Kwan-Il Kim, Hee-Jae Jung, Youngmin Bu and Beom-Joon Lee

Processes 2020, 8(1), 102; https://doi.org/10.3390/pr8010102 - 12 Jan 2020

Cited by 5 | Viewed by 4770

Abstract

In traditional medicine, lung-moistening herbal medicines (LMHM) are regarded as a major option for treating symptoms of pulmonary fibrosis (PF) including dry cough and dyspnea. As PF agents are being applied to the development of lung cancer agents, PF and lung cancer are [...] Read more.

In traditional medicine, lung-moistening herbal medicines (LMHM) are regarded as a major option for treating symptoms of pulmonary fibrosis (PF) including dry cough and dyspnea. As PF agents are being applied to the development of lung cancer agents, PF and lung cancer are reported to have high pathological and pharmacological relationships. This study was proposed to identify candidates for the treatment of PF via investigating the effect of LMHM on PF mouse model. PF was induced by intratracheal instillation of bleomycin. Six water extracts of LMHM such as Farfarae Flos (FAF), Trichosanthis Semen (TRS), Lilii Bulbus (LIB), Adenophorae Radix (ADR), Asteris Radix (ASR), and Scrophulariae Radix (SCR) were prepared and administered (300 mg/kg) orally for 10 days after induction. The changes in body weight, histopathology, and immune cell of bronchoalveolar lavage fluid (BALF) were investigated. Among those, LIB and ADR significantly decreased the deposition of collagen and septal thickness of alveolar and terminal bronchiole. Moreover, SCR, TRS, LIB, and ADR decreased total cells, macrophages, and lymphocytes in BALF. Taken together, ADR and LIB could be the candidates to reduce PF. Further studies on their effects at different doses and analysis of their underlying molecular mechanisms are needed. Full article

(This article belongs to the Special Issue Cancer Systems Biology and Natural Products)

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14 pages, 3986 KiB

Open AccessFeature PaperArticle

Acid-Base Flow Battery, Based on Reverse Electrodialysis with Bi-Polar Membranes: Stack Experiments

by Jiabing Xia, Gerhart Eigenberger, Heinrich Strathmann and Ulrich Nieken

Processes 2020, 8(1), 99; https://doi.org/10.3390/pr8010099 - 11 Jan 2020

Cited by 41 | Viewed by 8233

Abstract

Neutralization of acid and base to produce electricity in the process of reverse electrodialysis with bipolar membranes (REDBP) presents an interesting but until now fairly overlooked flow battery concept. Previously, we presented single-cell experiments, which explain the principle and discuss the potential of [...] Read more.

Neutralization of acid and base to produce electricity in the process of reverse electrodialysis with bipolar membranes (REDBP) presents an interesting but until now fairly overlooked flow battery concept. Previously, we presented single-cell experiments, which explain the principle and discuss the potential of this process. In this contribution, we discuss experiments with REDBP stacks at lab scale, consisting of 5 to 20 repeating cell units. They demonstrate that the single-cell results can be extrapolated to respective stacks, although additional losses have to be considered. As in other flow battery stacks, losses by shunt currents through the parallel electrolyte feed/exit lines increases with the number of connected cell units, whereas the relative importance of electrode losses decreases with increasing cell number. Experimental results are presented with 1 mole L⁻¹ acid (HCl) and base (NaOH) for open circuit as well as for charge and discharge with up to 18 mA/cm² current density. Measures to further increase the efficiency of this novel flow battery concept are discussed. Full article

(This article belongs to the Special Issue Electrolysis Processes)

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16 pages, 2225 KiB

Open AccessArticle

Assessment of the Usefulness of the Twin-Screw Press in Terms of the Pressing Efficiency and Antioxidant Properties of Apple Juice

by Kamil Wilczyński, Zbigniew Kobus, Rafał Nadulski and Marek Szmigielski

Processes 2020, 8(1), 101; https://doi.org/10.3390/pr8010101 - 11 Jan 2020

Cited by 9 | Viewed by 4302

Abstract

The paper presents the possibility of applying a twin-screw press for juice extraction from apples with different textural properties. The research was carried out with six different varieties; namely, Granny Smith, Modi, Ligol, Lobo, Boscop and Szampion. During the experiment, the following properties [...] Read more.

The paper presents the possibility of applying a twin-screw press for juice extraction from apples with different textural properties. The research was carried out with six different varieties; namely, Granny Smith, Modi, Ligol, Lobo, Boscop and Szampion. During the experiment, the following properties were measured: texture properties, pressing yield and polyphenolic content; and ascorbic acid content and antioxidant activity both in raw apples and apple juice. Based on the analysis, three hardness levels of apples can be distinguished, impacting the course of juice pressing in a twin-screw press (low hardness below 30 N, medium hardness 30–50 N and high hardness 50 N). The study showed that only high hardness apples are suitable for pressing on a twin-screw press. The mechanism by which texture properties influence the juice pressing process in the studied press was explained. It was further demonstrated that the hardness of apples has a positive impact on the degree of extraction of polyphenols and ascorbic acid into apple juice. This is caused by the different fracture patterns of tissues with different mechanical properties. High hardness apples (Granny Smith and Modi) were characterized by a considerably greater degree of bioactive substance extraction into juice than medium hardness apples. Full article

(This article belongs to the Collection Sustainable Food Processing Processes)

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13 pages, 2089 KiB

Open AccessArticle

Preparation of Sawdust-Filled Recycled-PET Composites via Solid-State Compounding

by Rula M. Allaf, Esraa Albarahmieh and Mohammad Futian

Processes 2020, 8(1), 100; https://doi.org/10.3390/pr8010100 - 11 Jan 2020

Cited by 15 | Viewed by 6318

Abstract

Recently, consumer markets have shown great interest in sustainable products. Considerable research efforts are headed towards developing biodegradable and recyclable polymers and composites. In this study, the fabrication of a wood–plastic composite (WPC) via solid state compounding has been examined. Polyethylene terephthalate (PET) [...] Read more.

Recently, consumer markets have shown great interest in sustainable products. Considerable research efforts are headed towards developing biodegradable and recyclable polymers and composites. In this study, the fabrication of a wood–plastic composite (WPC) via solid state compounding has been examined. Polyethylene terephthalate (PET) and wood sawdust waste as major components of waste and challenging materials for the manufacturing of WPCs have been explored. Furthermore, the addition of poly(ε-caprolactone) as a biodegradable plasticizing agent was investigated. Composite powders were prepared by cryogenic solid-state milling (cryomilling) according to a statistical mixture design. Mechanical and water absorption properties were inspected on film samples obtained by hot pressing. Different formulations resulted in a variety of colors, textures, water interactions and mechanical properties. A sawdust content of approximately 25 vol.% was optimal for the best combination of properties. The results indicated that cryomilling is technically advantageous in the production of WPCs. Full article

(This article belongs to the Special Issue Green Synthesis Processes of Polymers & Composites)

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15 pages, 5024 KiB

Open AccessArticle

Influence of Eccentricity on Hydrodynamic Characteristics of Nuclear Reactor Coolant Pump under Different Cavitation Conditions

by Yuanyuan Zhao, Bin Lin, Xiuli Wang, Rongsheng Zhu and Qiang Fu

Processes 2020, 8(1), 98; https://doi.org/10.3390/pr8010098 - 10 Jan 2020

Cited by 5 | Viewed by 2720

Abstract

In order to study the influence of eccentricity on hydrodynamic characteristics of nuclear reactor coolant pump under different cavitation conditions, five different schemes were obtained by analyzing and optimizing the existing structural schemes. Based on the RNG k-ε model (Renormalization Group with k-epsilon [...] Read more.

In order to study the influence of eccentricity on hydrodynamic characteristics of nuclear reactor coolant pump under different cavitation conditions, five different schemes were obtained by analyzing and optimizing the existing structural schemes. Based on the RNG k-ε model (Renormalization Group with k-epsilon turbulence models) and two-fluid two-phase flow model, the unsteady numerical analysis and test verification of different designed schemes are carried out by using the flow field software ANSYS CFX. The results of research show that different eccentricities will affect the nuclear reactor coolant pump’s head under different cavitation conditions, and the corresponding head in the scheme with the eccentricity of 5mm under the fracture cavitation condition is lower than that of the other schemes. When the impeller rotates at a certain angle from the initial position under critical and severe cavitation conditions, the radial force acting on the rotor system will fluctuate greatly. Under the condition of fracture cavitation, the radial force changed periodically and the resultant force value is small. Compared to the original scheme, the peak value of radial force is 6° clockwise after eccentricity of the impeller appeared. With the aggravation of cavitation condition, the axial force value of impeller decreases, but the corresponding amplitude of the impeller increases. Under critical and severe cavitation conditions, the maximum axial force amplitude of the nuclear reactor coolant pump appears in the two times blade frequency, and in the broken cavitation condition, the maximum axial force amplitude appears at the shaft frequency. When the eccentricity is 20 mm, the axial force fluctuates most under critical and severe cavitation conditions, and when the eccentricity is 10 mm, the corresponding axial force is smaller than that of the original scheme. When the eccentricity is 5 mm, the axial force on the impeller is the smallest, but the amplitude is the largest under the condition of fracture cavitation. Full article

(This article belongs to the Section Advanced Digital and Other Processes)

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11 pages, 693 KiB

Open AccessFeature PaperArticle

Drying Kinetics, Grinding Characteristics, and Physicochemical Properties of Broccoli Sprouts

by Dariusz Dziki, Ewa Habza-Kowalska, Urszula Gawlik-Dziki, Antoni Miś, Renata Różyło, Zbigniew Krzysiak and Waleed H. Hassoon

Processes 2020, 8(1), 97; https://doi.org/10.3390/pr8010097 - 10 Jan 2020

Cited by 10 | Viewed by 5213

Abstract

In this study, we studied the drying process, grinding characteristics and physicochemical characteristics of broccoli sprouts (BS). The seeds of broccoli were germinated at 20 °C for 3 and 6 days. Then, the seeds were air- and freeze-dried, and the Page model was [...] Read more.

In this study, we studied the drying process, grinding characteristics and physicochemical characteristics of broccoli sprouts (BS). The seeds of broccoli were germinated at 20 °C for 3 and 6 days. Then, the seeds were air- and freeze-dried, and the Page model was used for prediction of drying kinetics of broccoli sprouts. It was observed that the drying time of BS decreased about twofold as the air-drying temperature increased from 40 to 80 °C. An increasing the air-drying temperature from 40 to 80 °C decreased the drying time by approximately twofold. Freeze-drying of sprouts took the longest drying time. Germination of seeds significantly decreased the value of grinding energy requirements, and the ground sprouts exhibited a different grinding pattern in comparison to ground non-germinated seeds. In terms of color parameters, the highest lightness and yellowness were found for freeze-dried sprouts. Redness and yellowness of sprouts increased with an increase in the air-drying temperature. The lowest total color difference was obtained for the freeze-dried sprouts. Higher drying temperature resulted in lower total phenolics content (TPC) and decreased antioxidant activity (AA). The highest TPC and AA were observed in air-dried sprouts (40 °C) and freeze-dried sprouts after 6 days of germination. Full article

(This article belongs to the Collection Sustainable Food Processing Processes)

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16 pages, 5455 KiB

Open AccessArticle

Hierarchical Cs–Pollucite Nanozeolite Modified with Novel Organosilane as an Excellent Solid Base Catalyst for Claisen–Schmidt Condensation of Benzaldehyde and Acetophenone

by Aleid Ghadah Mohammad S., Fitri Khoerunnisa, Severinne Rigolet, T. Jean Daou, Tau-Chuan Ling and Eng-Poh Ng

Processes 2020, 8(1), 96; https://doi.org/10.3390/pr8010096 - 10 Jan 2020

Cited by 7 | Viewed by 3677

Abstract

Cs–pollucite can be a potential solid base catalyst due to the presence of (Si-O-Al)⁻Cs⁺ basic sites. However, it severely suffers from molecular diffusion and pore accessibility problems due to its small micropore opening. Herein, we report the use of new [...] Read more.

Cs–pollucite can be a potential solid base catalyst due to the presence of (Si-O-Al)⁻Cs⁺ basic sites. However, it severely suffers from molecular diffusion and pore accessibility problems due to its small micropore opening. Herein, we report the use of new organosilane, viz. dimethyloctadecyl[3-(trimethoxysilyl)propyl]ammonium chloride (TPOAC), as a promising pore-expanding agent to develop the hierarchical structure in nanosized Cs–pollucite. In respect to this, four different amounts of TPOAC were added during the synthesis of hierarchical Cs–pollucite (CP-x, x = 0, 0.3, 1.0, or 2.0, where x is the molar ratio of TPOAC) in order to investigate the effects of TPOAC in the crystallization process of Cs–pollucite. The results show that an addition of TPOAC altered the physico-chemical and morphological properties of hierarchical Cs–pollucite, such as the crystallinity, crystallite size, pore size distribution, surface areas, pore volume, and surface basicity. The prepared solids were also tested in Claisen–Schmidt condensation of benzaldehyde and acetophenone, where 82.2% of the conversion and 100% selectivity to chalcone were achieved by the CP-2.0 catalyst using non-microwave instant heating (200 °C, 100 min). The hierarchical CP-2.0 nanocatalyst also showed better catalytic performance than other homogenous and heterogeneous catalysts and displayed a high catalyst reusability with no significant deterioration in the catalytic performance even after five consecutive reaction runs. Full article

(This article belongs to the Special Issue Synthesis and Application of Novel Nanocatalysts)

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