Processes

25 pages, 12203 KiB

Open AccessArticle

Influence Mechanism of Ambient Air Parameters on the Rotational Stall of an Axial Fan

by Hui Ma, Guangtong Tang, Chaoyang Wang, Tianlong Wang, Xin Li, Yonghui Jia, Yulong Qiu, Wei Yuan and Lei Zhang

Processes 2024, 12(8), 1781; https://doi.org/10.3390/pr12081781 - 22 Aug 2024

Viewed by 767

Abstract

This study investigates a dual-stage axial-flow fan within a specific power plant context. Numerical simulations encompassing both steady-state and stall conditions were conducted utilizing the Reynolds-averaged Navier–Stokes (RANS) equations coupled with the Realizable k–ε turbulence model. The findings reveal that, under [...] Read more.

This study investigates a dual-stage axial-flow fan within a specific power plant context. Numerical simulations encompassing both steady-state and stall conditions were conducted utilizing the Reynolds-averaged Navier–Stokes (RANS) equations coupled with the Realizable k–ε turbulence model. The findings reveal that, under normal operating conditions, there exists a positive correlation between the mass flow rate and outlet pressure with gas density while displaying a negative correlation with dynamic viscosity. Regardless of the changes in air density, the volumetric flow rate at the maximum outlet pressure of the fan remains essentially the same. When a stall occurs, the volumetric flow rate rapidly decreases to a specific value and then decreases slowly. The analysis of the three-dimensional flow field within the first-stage rotor was performed before and after the rotational stall occurrence. Notably, stall inception predominantly manifests at the blade tip. As the flow rate diminishes, the leakage area at the blade tip within a passage expands, directing the trajectory of the leakage vortex toward the leading edge of the blade. Upon reaching a critical flow rate, the backflow induced by the blade tip leakage vortex obstructs the entire passage at the blade tip, progressively evolving into a stall cell, thereby affecting flow within both passages concurrently. Full article

(This article belongs to the Special Issue Challenges and Advances of Process Control Systems)

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20 pages, 9296 KiB

Open AccessArticle

Research on Energy Dissipation of Hydrofoil Cavitation Flow Field with FBDCM Model

by Rui Huang, Yulong Wang, Haitao Xu, Chaohui Qiu and Wei Ma

Processes 2024, 12(8), 1780; https://doi.org/10.3390/pr12081780 - 22 Aug 2024

Viewed by 564

Abstract

In order to obtain a more detailed and comprehensive relationship between the cavitation phenomenon and energy loss, this paper takes an NACA66 hydrofoil as an example to analyze the specific relationship between the cavitation flow field and energy dissipation by using entropy production [...] Read more.

In order to obtain a more detailed and comprehensive relationship between the cavitation phenomenon and energy loss, this paper takes an NACA66 hydrofoil as an example to analyze the specific relationship between the cavitation flow field and energy dissipation by using entropy production theory, a ZGB cavitation model, and k-ε turbulence model which were modified by a Filter-Based Density Correction model (FBDCM). The results show that the modified k-ε model can effectively capture the morphology of cavity evolution in the cavitation flow field. The vortex dilatation term contributes the most to the vorticity transport in cavitation flow. The energy loss of the cavitation flow field is primarily composed of turbulent dissipation, which is primarily distributed in the area below the lifted attached cavity and inside the vortex induced by the cloud cavity. The direct dissipation entropy production is predominantly distributed in the area near the stagnation point of the hydrofoil’s leading edge and inside the cavity. The wall entropy production is chiefly distributed in the area where the cavity is not covered. The cavitation entropy production mainly occurs on the vapor–liquid interface, and the value is negative, indicating that the vapor–liquid conversion in the cavitation process needs to absorb energy from the flow field. Full article

(This article belongs to the Section Energy Systems)

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36 pages, 12416 KiB

Open AccessArticle

The Influence of the Geometric Parameters of an Impeller on the Transport Capability of Long Flexible Fiber in a Non-Clogging Pump

by Rongsheng Liu, Qiang Zhang, Suguo Zhuang and Kai Wang

Processes 2024, 12(8), 1779; https://doi.org/10.3390/pr12081779 - 22 Aug 2024

Viewed by 600

Abstract

The influence of a different blade number, blade wrapping angle and blade outlet angle on flexible fiber passing performance is analyzed numerically with CFD-DEM coupling. The results demonstrate that a non-clogging pump with two blades exhibits superior passing performance compared to the non-clogging [...] Read more.

The influence of a different blade number, blade wrapping angle and blade outlet angle on flexible fiber passing performance is analyzed numerically with CFD-DEM coupling. The results demonstrate that a non-clogging pump with two blades exhibits superior passing performance compared to the non-clogging pump with three blades. Specifically, when the fiber length L is 150 mm, the passing performance of the pump with different wrapping angles is 270° > 240° > 300°, from highest to lowest, and the transport time T₀ is 0.27 s, 0.34 s, 0.46 s, respectively. When the length L is 200 mm, the passing performance is 240° > 270° ≈ 300°, and the transport time T₀ is 0.48 s, 0.55 s, and 0.55 s, respectively. When the fiber length L is 250 mm, the passing performance is 240° ≈ 270° > 300°. When the fiber length L is 150 mm, the passing performance of the pump with different outlet angles is 15° > 25° > 20°, and the transport time T₀ is 0.17 s, 0.27 s, and 0.34 s, respectively. When the fiber length L is 200 mm, the passing performance is 25° > 15° ≈ 20° and the transport time T₀ is 0.26 s, 0.50 s, and 0.48 s, respectively. When the fiber length L is 250 mm, the passing performance is 25° > 15° > 20°, and the transport time T₀ is 0.31 s, 0.54 s and 0.96 s, respectively. Full article

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

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31 pages, 11743 KiB

Open AccessArticle

Pressurized Regenerative Calcium Cycle for Utility-Scale Energy Storage: A Techno-Economic Assessment

by Behdad Moghtaderi, Priscilla Tremain and John Warner

Processes 2024, 12(8), 1778; https://doi.org/10.3390/pr12081778 - 22 Aug 2024

Viewed by 1252

Abstract

The University of Newcastle (UON) and Jord International Pty Ltd. (Jord) have jointly developed a novel concept for the storage of energy from renewable and fossil fuel sources. The process, referred to as the pressurized regenerative calcium cycle (PRC²), relies on [...] Read more.

The University of Newcastle (UON) and Jord International Pty Ltd. (Jord) have jointly developed a novel concept for the storage of energy from renewable and fossil fuel sources. The process, referred to as the pressurized regenerative calcium cycle (PRC²), relies on cyclic carbonation and calcination of CaO/CaCO₃, in which low-cost electrical energy (i.e., off-peak, or excess generation from renewables) drives the calcination reaction and electricity is generated as required through the carbonation reaction. Initial proof-of-concept testing of the process was previously conducted within an existing fluid bed reactor at UON. The PRC² concept was successfully demonstrated by maintaining the fluid bed reactor at a constant temperature by using the heat released during the reaction of calcium oxide and carbon dioxide. Following proof-of-concept testing, further refinement of the PRC² process, which is the subject of this paper, was conducted to address its shortcomings and, importantly, facilitate the detailed design, construction, and operation of a large-scale demonstration plant. Nine different configurations were examined for the PRC² process, for each of which a combined experimental, process modelling, and techno-economic assessment was completed. Experimental investigations were conducted to determine the suitability of carbonate materials for the PRC² process. Process modelling and levelized cost of storage (LCOS) calculations were concurrently conducted and revealed that the molten salt approach (Option 9) was the most promising, having superior round-trip efficiency and lowest LCOS. For practical reasons (e.g., technical difficulties of working with molten salts), Option 3 (indirect power generation using a fluid bed reactor) was deemed the most feasible option for a demonstration scale plant. The LCOS for Option 3 (assuming a 100 MWe capacity) was calculated to be AUD 245 per MWh, which is on par with the cost of batteries for peak power replacement applications (the cost associated with lithium-ion batteries is AUD 370 per MWh). Full article

(This article belongs to the Special Issue Advances in Renewable Energy Systems (2nd Edition))

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12 pages, 4034 KiB

Open AccessArticle

A Study on the Influence of Oxy-Hydrogen Gas Flame on the Combustion Stability of Coal Powder and Nitrogen Oxide Emissions

by Wenke Xiao, Jie Cui, Honggang Pan, Honglei Zhao, Shuo Yang, Zhijia Xue, Yudong Fu and Youning Xu

Processes 2024, 12(8), 1777; https://doi.org/10.3390/pr12081777 - 22 Aug 2024

Viewed by 560

Abstract

Co-firing zero-carbon fuels as an effective emission reduction strategy in coal combustion processes has garnered widespread attention. This paper proposes utilizing the combustion performance of oxy-hydrogen gas derived from zero-carbon fuels to address issues related to low-concentration coal powder combustion and nitrogen oxide [...] Read more.

Co-firing zero-carbon fuels as an effective emission reduction strategy in coal combustion processes has garnered widespread attention. This paper proposes utilizing the combustion performance of oxy-hydrogen gas derived from zero-carbon fuels to address issues related to low-concentration coal powder combustion and nitrogen oxide emissions. A test apparatus for coal powder combustion initiated by oxy-hydrogen gas flames was constructed, and experimental and simulation methods were employed to study the impact of oxy-hydrogen gas flame initiation on the temperature inside the combustion chamber, coal powder gasification combustion reactions, and nitrogen oxide emissions. The results indicate that with an excess air coefficient of 0.8, as the oxy-hydrogen gas flow rate increased from 0.022 kg/h to 0.789 kg/h, the average temperature inside the combustion chamber increased from 801 K to 1459 K. The volatile matter release rate and its combustion reaction rate increased, leading to a decrease in volatile matter content. The peak concentration of volatiles was shifted from a position of 68 mm to 7 mm, and the proportion of C_char–H₂O reaction increased from 5% to 34%. NO emissions decreased from 132 ppm to 68 ppm, and the rate of reduction in NO emissions decreased from 15.38% to 5.49%. Full article

(This article belongs to the Section Energy Systems)

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21 pages, 5317 KiB

Open AccessArticle

Runoff Prediction for Hydrological Applications Using an INFO-Optimized Deep Learning Model

by Weisheng Wang, Yongkang Hao, Xiaozhen Zheng, Tong Mu, Jie Zhang, Xiaoyuan Zhang and Zhenhao Cui

Processes 2024, 12(8), 1776; https://doi.org/10.3390/pr12081776 - 22 Aug 2024

Viewed by 667

Abstract

Runoff prediction is essential in water resource management, environmental protection, and agricultural development. Due to the large randomness, high non-stationarity, and low prediction accuracy of nonlinear effects of the traditional model, this study proposes a runoff prediction model based on the improved vector [...] Read more.

Runoff prediction is essential in water resource management, environmental protection, and agricultural development. Due to the large randomness, high non-stationarity, and low prediction accuracy of nonlinear effects of the traditional model, this study proposes a runoff prediction model based on the improved vector weighted average algorithm (INFO) to optimize the convolutional neural network (CNN)-bidirectional long short-term memory (Bi-LSTM)-Attention mechanism. First, the historical data are analyzed and normalized. Secondly, CNN combined with Attention is used to extract the depth local features of the input data and optimize the input weights of Bi-LSTM. Then, Bi-LSTM is used to study the time series feature depth analysis data from both positive and negative directions simultaneously. The INFO parameters are optimized to provide the optimal parameter guarantee for the CNN-Bi-LSTM-Attention model. Based on a hydrology station’s water level and flow data, the influence of three main models and two optimization algorithms on the prediction accuracy of the CNN-Bi-LSTM-Attention model is compared and analyzed. The results show that the fitting coefficient, R2, of the proposed model is 0.948, which is 7.91% and 3.38% higher than that of Bi-LSTM and CNN-Bi-LSTM, respectively. The R2 of the vector-weighted average optimization algorithm (INFO) optimization model is 0.993, which is 0.61% higher than that of the Bayesian optimization algorithm (BOA), indicating that the method adopted in this paper has more significant forecasting ability and can be used as a reliable tool for long-term runoff prediction. Full article

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

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16 pages, 17357 KiB

Open AccessArticle

Research for Flow Behavior of Heavy Oil by N₂ Foam-Assisted Steam (NFAS) Flooding: Microscopic Displacement Experiment Study

by Qiang Fu, Zhihao Yang, Yongfei Liu and Mingqiang Chen

Processes 2024, 12(8), 1775; https://doi.org/10.3390/pr12081775 - 22 Aug 2024

Viewed by 543

Abstract

Steam flooding is easily induced to transverse flow, with a limited swept area and low displacement efficiency. Therefore, chemical agents have been used to assist in steam flooding for heavy oil extraction. However, research into the driving mechanisms and modes of occurrence of [...] Read more.

Steam flooding is easily induced to transverse flow, with a limited swept area and low displacement efficiency. Therefore, chemical agents have been used to assist in steam flooding for heavy oil extraction. However, research into the driving mechanisms and modes of occurrence of residual oil is insufficient. In this work, a flooding simulation was conducted to understand the occurrence mechanism of residual oil during the flooding process in heavy oil reservoirs. First, the foam properties of a novel DES (Deep Eutectic Solvent) and CTAB (Cetyltrimethyl Ammonium Bromide) composite system with ultra-low interfacial tension were tested. The optimal concentration and gas–liquid ratio of the foam agent solution were determined. Secondly, the NFAS (N₂ foam-assisted steam flooding) was carried out after steam flooding, and the flow behavior of crude oil at different flow pathway zones was researched. In the end, the remaining oil morphology and distribution characteristics under different displacement times were analyzed, determining the mode of remaining oil occurrence during NFAS flooding. The results show that (1) the novel DES and CTAB system has good foam properties. The best concentration is 0.5 wt%, and the optimal ratio of gas to liquid is 1:1. (2) In the steam flooding stage, the columnar remaining oil in the narrow hole near the flow pathway increases, and the cluster remaining oil in the far flow channel changes into film and columnar. (3) During NFAS displacement, the residual oil primarily presents a state of fully mixing the O/W emulsion formed after blending and dispersing with oil, gas, and water. (4) After the NFAS flooding stage, the remaining oil was distributed in each throat. The remaining oil in the near passage is mostly blocked by foam in large holes with a pore coordination number of 4 and 5. The residual oil in the distant runner is distributed in the thick and middle throats. (5) NFAS flooding outperforms steam flooding by significantly decreasing residual oil in narrow passages of the main flow channel and near flow channels, resulting in a substantial 44.9% increase in overall recovery rate. Full article

(This article belongs to the Section Energy Systems)

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15 pages, 6330 KiB

Open AccessArticle

Study on Wax Deposition Process of Crude Oil System under Shear Flow Field Conditions

by Haibo Liu, Chao Yang, Jingjing Qi, Chao Liu, Haijun Luo and Bingfan Li

Processes 2024, 12(8), 1774; https://doi.org/10.3390/pr12081774 - 21 Aug 2024

Viewed by 789

Abstract

This paper adopted numerical simulation based on the MD method to research the effect of different shear rates and wax contents on wax deposition focused on crude oil. The findings indicated that under shear flow conditions, there were primarily four steps during deposition. [...] Read more.

This paper adopted numerical simulation based on the MD method to research the effect of different shear rates and wax contents on wax deposition focused on crude oil. The findings indicated that under shear flow conditions, there were primarily four steps during deposition. Diffusion was the initial stage when wax diffused onto the metal surface. In the second stage, wax adsorbed onto a metal surface aligned itself parallel to the surface via Brownian motion, generating two different kinds of deposits. Subsequently, agglomerates were formed between the adsorbed deposits and the wax as a result of molecular interactions and bridging effects. Furthermore, the second and third deposited layers gradually showed peeling off and sliding under shear force. The wax deposition process was comparable for crude oil systems with varying shear rates and wax concentrations, and the deposited layer’s thickness on the metal surface was constant. The first, second, and third deposits were mainly adsorbed at 0.122 nm, 0.532 nm, and 1.004 nm away from the Fe surface, and the interaction energy between crude oil molecules and the Fe surface was mainly vdW force. The contact between Fe and wax progressively increased as the shear rate and wax content rose, promoting the wax adsorption on the metal surface and causing more of the wax to congregate in the deposited wax. The findings of the research can theoretically help a more thorough comprehension of the wax deposition. Full article

(This article belongs to the Topic Oil and Gas Pipeline Network for Industrial Applications)

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23 pages, 8840 KiB

Open AccessArticle

Study on the Evolution of Mechanical Properties and Acoustic Emission of Medium-Permeability Sandstone under Multi-Level Cyclic Loading Stress Paths

by Debin Xia, Hejuan Liu, Jianjun Liu, Yintong Guo, Mancang Liu, Xiaosong Qiu, Haibo Li, Hongying Tan and Jun Lu

Processes 2024, 12(8), 1773; https://doi.org/10.3390/pr12081773 - 21 Aug 2024

Viewed by 679

Abstract

Depleted gas reservoirs are important natural gas storage media, thus research on the mechanical properties and damage evolution of reservoir rocks under alternating load conditions has significant practical implications for seal integrity studies. This paper conducted multi-level cyclic loading triaxial compression experiments on [...] Read more.

Depleted gas reservoirs are important natural gas storage media, thus research on the mechanical properties and damage evolution of reservoir rocks under alternating load conditions has significant practical implications for seal integrity studies. This paper conducted multi-level cyclic loading triaxial compression experiments on medium-porosity medium-permeability sandstone under different confining pressures and used acoustic emission (AE) instruments to detect the AE characteristics during the experiment, analyzing the mechanical characteristics, AE, and damage evolution characteristics. The experimental results show that after cyclic loading, the peak strength of sandstone increased by 14–17%. With the increase in the upper limit stress of cyclic loading, the elastic modulus showed a trend of first increasing and then gradually decreasing. The damage variable of rock samples rose with a rise in the upper limit stress of cyclic loading and confining pressure, and the rock damage was mostly localized at the peak stress. The AE b-value increased generally as confining pressure increased, showing that fractures occurred quicker and more unevenly at lower confining pressures. The distribution of RA-AF values shows that a sudden increase in stress causes the initiation and expansion of cracks in medium-permeability sandstone, and that tensile and shear cracks form continuously during the cyclic loading process, with shear cracks developing more pronounced. This research can provide some theoretical guidance for the long-term stable operation and pressure enhancement expansion of depleted gas reservoir storage facilities. Full article

(This article belongs to the Special Issue Recent Advances in Environment and Energy Related Processes in Offshore Geotechnical Engineering)

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16 pages, 1473 KiB

Open AccessArticle

Integrating MILP, Discrete-Event Simulation, and Data-Driven Models for Distributed Flow Shop Scheduling Using Benders Cuts

by Roderich Wallrath and Meik B. Franke

Processes 2024, 12(8), 1772; https://doi.org/10.3390/pr12081772 - 21 Aug 2024

Viewed by 1016

Abstract

Digitalization plays a crucial role in improving the performance of chemical companies. In this context, different modeling, simulation, and optimization techniques such as MILP, discrete-event simulation (DES), and data-driven (DD) models are being used. Due to their heterogeneity, these techniques must be executed [...] Read more.

Digitalization plays a crucial role in improving the performance of chemical companies. In this context, different modeling, simulation, and optimization techniques such as MILP, discrete-event simulation (DES), and data-driven (DD) models are being used. Due to their heterogeneity, these techniques must be executed individually, and holistic optimization is manual and time-consuming. We propose Benders decomposition to combine these techniques into one rigorous optimization procedure. The main idea is that heterogeneous models can simultaneously be optimized as Benders subproblems. We illustrate this concept with the distributed permutation flow shop scheduling problem (DPFSP) and assume that a MILP, DES, and DD model exist for three flow shops. Our approach can compute bounds and report gap information on the optimal makespan for five medium-sized literature instances. The approach is promising because it enables the optimization of heterogeneous models and makes it possible to build optimization capabilities on an existing model and tool landscape in chemical companies. Full article

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

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12 pages, 1406 KiB

Open AccessArticle

Qualitative and Quantitative Potential of Low-Cost Near-Infrared (NIR) Devices for Rapid Analysis of Infant Formulas for Regular and Special Needs

by Iva Majić, Marta Zajec, Maja Benković, Tamara Jurina, Ana Jurinjak Tušek, Davor Valinger and Jasenka Gajdoš Kljusurić

Processes 2024, 12(8), 1771; https://doi.org/10.3390/pr12081771 - 21 Aug 2024

Viewed by 613

Abstract

Infant formulas and their quality are an extremely important factor for proper growth and development and their composition and nutritional quality are extremely important. Fast, green, and cheap quality analysis methods are definitely desirable. Therefore, the aim of this work was to examine [...] Read more.

Infant formulas and their quality are an extremely important factor for proper growth and development and their composition and nutritional quality are extremely important. Fast, green, and cheap quality analysis methods are definitely desirable. Therefore, the aim of this work was to examine the potential of applying near-infrared (NIR) spectroscopy using two devices: a (i) laboratory NIR analyzer and (ii) portable NIR device. Both devices record the vibrations of molecules in the NIR region of 900–1699 nm. Infant formulas intended for children up to 6 months (n = 6) and for infants with a sensitive digestive system or confirmed allergy to cow’s milk proteins (n = 5) were tested. Each infant formula was recorded in the form of powder and in the form of prepared samples corresponding to different ages, according to the instructions on the product declaration. The parameters of color, conductivity, and total dissolved solids (TDS) were also measured. The measured parameters and the chemical composition of infant formulas were associated with NIR spectra and with the application of chemometric tools (principal component analysis (PCA) and partial least squares regression (PLSR)), the similarity and/or difference between the samples was determined and the qualitative/quantitative potential was determined through applications of both devices. Characteristic peaks at certain wavelengths indicate the presence of carbohydrates, proteins, and water were identified and are specific for regular and specific purpose infant formulas. It is precisely these specificities in the composition, which are visible in the NIR spectrum, that make it possible to distinguish samples on a qualitative level. The connection of NIR spectra as input variables and 22 parameters (color, TDS, conductivity, and energy–nutrient composition) as output variables, using PLSR, gave an insight into the quantitative potential, i.e., the possibility of predicting the observed parameters on the basis of NIR spectra (recorded using two devices). The quantitative potential was confirmed on the basis of model parameters that resulted in acceptable values for both NIR devices: the coefficient of determination for the calibration, R_c² > 0.9, and Range Error Ratio, RER > 6. Full article

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

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21 pages, 7151 KiB

Open AccessArticle

Establishment and Research of Cotton Stalk Moisture Content–Discrete Element Parameter Model Based on Multiple Verification

by Tao Wu, Limin Yan, Deli Jiang, Haixiao Gou, Xuanhe Fu and Jinhao Zhang

Processes 2024, 12(8), 1770; https://doi.org/10.3390/pr12081770 - 21 Aug 2024

Viewed by 624

Abstract

In view of the large difference in moisture content of cotton stalk in autumn in Xinjiang, the existing process of obtaining discrete element simulation parameters of cotton stalk is low in accuracy and complicated in operation, leading to the problems of poor universality [...] Read more.

In view of the large difference in moisture content of cotton stalk in autumn in Xinjiang, the existing process of obtaining discrete element simulation parameters of cotton stalk is low in accuracy and complicated in operation, leading to the problems of poor universality and low accuracy in regard to the discrete element simulation parameter-calibration method in the process of mechanized transportation, throwing and returning to the field. Therefore, the experimental study on cotton stalk with different moisture content was carried out with the accumulation angle as the response value, so as to construct a parameter model that can quickly and accurately calibrate cotton stalk with different levels of moisture content. The model has high applicability and flexibility, and it can be widely used in the simulation test of various cotton field-operation machinery, such as a residual film-recycling machine, cotton picker, crushing and returning machine and other equipment. The water content–accumulation angle model was established by the cylinder-lifting method, and the correlation coefficient of the model was 0.9993. Based on EDEM 2020 software, the Hertz–Mindlin model was used to simulate the stacking angle of cotton stalk, and the rolling friction coefficient, static friction coefficient and collision recovery coefficient between cotton stalk and cotton stalk–steel were obtained. Through the Plackett–Burman test, climbing test and Box–Behnken test, three significant parameters, namely the rolling friction coefficient, static friction coefficient and static friction coefficient between cotton stalk and steel, were selected from discrete element simulation parameters to characterize the moisture content of cotton stalk, and the accumulation angle–discrete element parameter model was established. The p-value of the model was less than 0.0001, and the relative error was only 2.67%. Based on the moisture content–stacking angle model and the stacking angle–discrete element parameter model, the moisture content–discrete element parameter model was constructed. The model was verified by the cylinder-lifting method and the plate-drawing method, and the relative error was only 2.79%. Finally, the model was further verified by comparing the effect of the throwing uniformity between the mechanical simulation test and field test, and the relative error was only 4.75%. The test proves that the moisture content–discrete element parameter model is accurate and reliable, not only providing the design basis and support for the mechanization research of cotton stalk conveying and returning to the field in Xinjiang but also providing ideas for the calibration of discrete element simulation parameters of other crop straws. Full article

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

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11 pages, 1114 KiB

Open AccessArticle

Regional Grid Power Supply Radius Planning—A Sensitivity Constraint-Based Approach

by You Yu, Jingfu Tian, Tao Li, Zhenting Sun, Jianbin Ci, Jinming Li, Zengqiang Lai, Zhenji Yao and Jingshan Mo

Processes 2024, 12(8), 1769; https://doi.org/10.3390/pr12081769 - 21 Aug 2024

Viewed by 473

Abstract

This paper addresses the correlation between the coverage of regional power grid supply and the sensitivity of line backup protection. Through a theoretical analysis of the calculation method for line backup protection sensitivity in power grids, and in accordance with grid regulations, this [...] Read more.

This paper addresses the correlation between the coverage of regional power grid supply and the sensitivity of line backup protection. Through a theoretical analysis of the calculation method for line backup protection sensitivity in power grids, and in accordance with grid regulations, this paper proposes a planning method for the supply range of power grid lines that meets sensitivity constraints. And the reliability of this method in calculating and evaluating the optimal power supply radius of lines is verified by taking the example of an actual 66 kV grid in a region. This method can be used to optimise network structure, improve the reliability and economy of the grid, and guide the planning and construction of regional grids. Full article

(This article belongs to the Special Issue AC and DC Power Grids System Technologies: Analysis, Control and Practical Applications)

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18 pages, 10439 KiB

Open AccessFeature PaperArticle

Experimental Study of the Characteristics of HI Distillation in the Thermochemical Iodine–Sulfur Cycle for Hydrogen Production

by Jinxu Zhang, Bo Ling, Yong He, Yanqun Zhu and Zhihua Wang

Processes 2024, 12(8), 1768; https://doi.org/10.3390/pr12081768 - 21 Aug 2024

Cited by 1 | Viewed by 690

Abstract

Hydrogen energy, as a clean, renewable, and high-calorific energy carrier, has garnered significant attention globally. Among various hydrogen production methods, the thermochemical iodine–sulfur (I-S) cycle is considered the most promising due to its high efficiency and adaptability for large-scale industrial applications. This study [...] Read more.

Hydrogen energy, as a clean, renewable, and high-calorific energy carrier, has garnered significant attention globally. Among various hydrogen production methods, the thermochemical iodine–sulfur (I-S) cycle is considered the most promising due to its high efficiency and adaptability for large-scale industrial applications. This study focuses on the distillation characteristics of the HI_x (HI–I₂–H₂O) solution within the I-S cycle, which is crucial for achieving the high-concentration HI necessary for efficient hydrogen production. Previous methods, including phosphoric acid extraction–distillation and reactive distillation, have addressed azeotrope issues but introduced complexities and equipment demands. This research constructs a hypo-azeotropic HI_x solution distillation experimental system and uses the Aspen Plus v14 software to optimize distillation parameters. By analyzing the effects of feed stage, reflux ratio, and feed temperature, the study provides essential data for improving distillation efficiency and supports the scale-up of I-S cycle technology. The findings indicate that optimal distillation is achieved with a feed position at 1/3 column height, a reflux ratio of 1.4, and a feed temperature near the boiling point, enhancing the feasibility of industrial hydrogen production via the I-S cycle. Full article

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

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15 pages, 5136 KiB

Open AccessArticle

Numerical Simulation of Fracture Propagation Induced by Water Injection in Tight Oil Reservoirs

by Dengke Shi, Shiqing Cheng, Wenpeng Bai, Xiuwei Liu and Dingning Cai

Processes 2024, 12(8), 1767; https://doi.org/10.3390/pr12081767 - 21 Aug 2024

Viewed by 742

Abstract

Dynamic fracture propagation significantly affects water flooding efficiency in tight oil reservoirs. This phenomenon, where moderate fracture openings can enhance water flooding volume and alleviate injection challenges, has been underexplored in current literature. Understanding dynamic fracture behavior poses a challenge due to the [...] Read more.

Dynamic fracture propagation significantly affects water flooding efficiency in tight oil reservoirs. This phenomenon, where moderate fracture openings can enhance water flooding volume and alleviate injection challenges, has been underexplored in current literature. Understanding dynamic fracture behavior poses a challenge due to the difficulty in characterizing them within traditional reservoir numerical simulators. In this study, we propose a numerical simulation method that integrates the KGD dynamic fracture model with a two-phase flow model. This approach enables detailed exploration of dynamic fracture evolution in reservoir scenarios featuring one injector and one production well. Our findings reveal that fractures extend from the water injection well to the oil production well, exhibiting rapid initial growth followed by a slower rate. Fluctuations in fracture tip pressure correspond to cycles of opening and closure. We observe that cumulative oil production increases more rapidly when injection pressure exceeds the fracture opening pressure. However, this growth rate diminishes beyond a certain threshold, highlighting the critical role of injection parameters in dynamic fracture efficacy. Optimal water flooding performance is achieved when injecting water slightly above the fracture opening pressure. Furthermore, we compare water cut curves generated by conventional commercial simulators with our fracture propagation model. Our model’s water cut curve aligns better with on-site data, indicating improved historical fitting accuracy. In conclusion, our study underscores the importance of dynamic fractures in enhancing water flooding efficiency in tight oil reservoirs and presents a robust numerical simulation framework for better understanding and management of reservoir dynamics. Full article

(This article belongs to the Section Energy Systems)

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24 pages, 17371 KiB

Open AccessArticle

Study on the Combined Effects of Bromelain (Ananas comosus) Enzyme Treatment and Bacteria Cultures on the Physicochemical Properties and Oxidative Stability of Horse Meat

by Duman Orynbekov, Kumarbek Amirkhanov, Zhanar Kalibekkyzy, Farida Smolnikova, Bakhytkul Assenova, Almagul Nurgazezova, Gulnur Nurymkhan, Amirzhan Kassenov, Sholpan Baytukenova and Zhanibek Yessimbekov

Processes 2024, 12(8), 1766; https://doi.org/10.3390/pr12081766 - 21 Aug 2024

Cited by 1 | Viewed by 844

Abstract

This study investigates the impact of bromelain, a plant enzyme, on the physicochemical and sensory properties of horse meat, as well as the effects of different bacterial cultures (Lactococcus lactis, Lactococcus lactis subsp. lactis biovar diacetylactis, Lactobacillus acidophilus, and [...] Read more.

This study investigates the impact of bromelain, a plant enzyme, on the physicochemical and sensory properties of horse meat, as well as the effects of different bacterial cultures (Lactococcus lactis, Lactococcus lactis subsp. lactis biovar diacetylactis, Lactobacillus acidophilus, and Bifidobacterium longum) on the inhibition of lipid oxidation and control of pH during chilled storage. Horse meat (longissimus dorsi) samples (n = 14) were treated with bromelain in two forms (powder and aqueous solution) and with three methods: immersion in enzyme solution, spreading enzyme powder on meat, and syringing enzyme solution into the meat. After fermentation, a part of the meat samples (n = 6) was treated with different bacteria compositions at a 5% weight ratio and stored at 0–2 °C for 6 days. Injecting 3–5% bromelain solutions was most effective at tenderizing the meat, reducing shear force by up to 56% after 8 h. This injection also maximized the water-holding capacity (78–81%) and minimized cooking losses (21–26%), compared to 38% for the control meat sample without treatment. Syringing with 3% bromelain yielded the highest sensory scores across the tenderness, flavor, and overall palatability parameters. The combination of L. acidophilus, Lc. lactis, and B. longum at a ratio of 1.5:1.5:2 was highly effective in reducing oxidative spoilage and optimizing pH levels, thereby ensuring extended meat storability. This study demonstrates that bromelain treatment is an effective method for improving the tenderness, WHC, and sensory properties of horse meat. The LAB combination showed efficient acid formation, crucial for enhancing meat preservation. Full article

(This article belongs to the Special Issue Enzymes and Microorganisms in Food Bioprocessing—Waste Recovery, Applications and Advances)

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13 pages, 4592 KiB

Open AccessArticle

Construction of Fe₂O₃-CuO Heterojunction Photoelectrode for Enhanced Efficiency of Solar Redox Flow Batteries

by Ping Lu, Zihan Zhang, Zixing Gu, Zhuo Li, Huaneng Su, Xiaozhong Shen and Qian Xu

Processes 2024, 12(8), 1765; https://doi.org/10.3390/pr12081765 - 21 Aug 2024

Viewed by 605

Abstract

To address the problem of suboptimal performance in deep eutectic solvents displayed by traditional TiO₂ photoelectrodes and Cu₂O photoelectrodes that have undergone simplistic modifications that result in a mismatch with battery discharge capacity, a method combining hydrothermal and dip-coating techniques [...] Read more.

To address the problem of suboptimal performance in deep eutectic solvents displayed by traditional TiO₂ photoelectrodes and Cu₂O photoelectrodes that have undergone simplistic modifications that result in a mismatch with battery discharge capacity, a method combining hydrothermal and dip-coating techniques was developed to create a Fe₂O₃-CuO heterojunction structure on the FTO surface. Then, the impact of the heterojunction structure on the performance of solar flow batteries was investigate in this study. The experimental findings reveal that the formation of the heterojunction structure effectively mitigates the recombination rate of photogenerated carriers within the photoelectrode. Furthermore, by meticulously adjusting the CuO loading, the harmonious balance between charging and discharging currents was achieved, thereby enhancing the overall performance of the solar redox flow batteries. In comparison to standalone Fe₂O₃ photoelectrodes, this innovative approach significantly broadens the spectrum of sunlight utilization. Notably, the fabricated Fe₂O₃/CuO-2 photoelectrode demonstrates a remarkable photocharging performance, far surpassing both Fe₂O₃ photoelectrodes and commercial TiO₂ photoelectrodes. Specifically, the Fe₂O₃/CuO-2 photoelectrode boosts an average current density of 598.68 μA∙cm⁻², with its charging current density being 2.74 and 5.15 larger, respectively, than that of the Fe₂O₃ and commercial TiO₂ photoelectrodes. Full article

(This article belongs to the Section Energy Systems)

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19 pages, 1679 KiB

Open AccessArticle

Recovery of Fennel Non-Polar Bioactives via Supercritical Carbon Dioxide Extraction

by Nina Marčac Duraković, Ena Cegledi, Ivona Elez Garofulić, Sandra Balbino, Sandra Pedisić, Stela Jokić, Verica Dragović-Uzelac and Maja Repajić

Processes 2024, 12(8), 1764; https://doi.org/10.3390/pr12081764 - 21 Aug 2024

Viewed by 583

Abstract

This study aimed to determine the optimal pressure and temperature for the maximum extraction yield and recovery of lipophilic bioactive compounds (BACs) during the supercritical carbon dioxide extraction (SCO₂) of fennel seeds. For this purpose, the SCO₂ pressure (78.6–361.4 bar) [...] Read more.

This study aimed to determine the optimal pressure and temperature for the maximum extraction yield and recovery of lipophilic bioactive compounds (BACs) during the supercritical carbon dioxide extraction (SCO₂) of fennel seeds. For this purpose, the SCO₂ pressure (78.6–361.4 bar) and temperature (35.9–64.1 °C) were varied and optimized, and all of the extracts obtained were analyzed for the volatiles, fatty acids, sterols, tocochromanols and carotenoids. The results showed that the maximum extract yield and content of all of the compounds analyzed favored a higher pressure (320 bar) and lower temperature (40 °C), except for the volatiles, which were the highest at 120 bar and 42 °C. However, the optimal SCO₂ conditions for obtaining the highest overall total lipophilic fraction were 320 bar and 40 °C, respectively. The fennel SCO₂ extract obtained under these conditions contained 18 volatiles (trans-anethole as the major component), 12 fatty acids (oleic and petroselinic as the major compounds), 12 sterols (β-sitosterol and stigmasterol as the major compounds), two pentacyclic triterpenoids (α-, β-amyrin), one tocopherol (α-tocopherol), two tocotrienols (γ-, δ-tocotrienol) as well as two carotenoids (lutein and β-carotene). The SCO₂ proved to be very efficient for the isolation of various lipophilic BACs from fennel, and the results of this study may be of interest to academia and industry. Full article

(This article belongs to the Special Issue Separation and Extraction Techniques in Food Processing and Analysis)

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15 pages, 4769 KiB

Open AccessArticle

Using the Methods-Time Measurement Calculator to Determine the Time Norms for Technological Sewing Operations in the Clothing Industry

by Snježana Kirin, Damir Kralj and Anica Hursa Šajatović

Processes 2024, 12(8), 1763; https://doi.org/10.3390/pr12081763 - 21 Aug 2024

Viewed by 789

Abstract

The work in the technological sewing process is carried out on machine systems characterised by machine–hand work, where the worker and the machine work simultaneously. Such a work system requires a high level of responsibility in terms of quality, quantity, and the correct [...] Read more.

The work in the technological sewing process is carried out on machine systems characterised by machine–hand work, where the worker and the machine work simultaneously. Such a work system requires a high level of responsibility in terms of quality, quantity, and the correct and timely execution of work, which requires workers to have fast and accurate reflexes, as well as exceptionally good psychomotor and visual skills. By applying the basic movements of the Methods-Time Measurement (MTM) system, the elaborated standard sets of hand sub-operations included in technological sewing operations, and the method of determining normal times for straight seams (RAV) and curved seams (ZAK), it is possible to determine the working method and time norm of individual technological sewing operations. The MTM Calculator software was developed to facilitate the determination of working methods and time norms on the basis of the MTM system. It can be used to quickly calculate the production time for a technological sewing operation. Full article

(This article belongs to the Special Issue Control Design and Numerical Computation in Manufacturing Process System)

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16 pages, 1605 KiB

Open AccessArticle

Modified PI Controller for Robustness Improvement of Quasi-Resonant Converters

by Oscar Miguel Rodríguez-Benítez, Isaac Ortega-Velázquez, Agustín Sánchez-Contreras and Gerardo Espinosa-Pérez

Processes 2024, 12(8), 1762; https://doi.org/10.3390/pr12081762 - 21 Aug 2024

Viewed by 769

Abstract

The challenge regarding the output voltage regulation control of quasi-resonant converters while concurrently fulfilling zero-current switching is addressed in this study. In particular, an alternative to the usual practice of considering fixed duty cycle operation is presented to deal with the narrow robustness [...] Read more.

The challenge regarding the output voltage regulation control of quasi-resonant converters while concurrently fulfilling zero-current switching is addressed in this study. In particular, an alternative to the usual practice of considering fixed duty cycle operation is presented to deal with the narrow robustness margin against load variations exhibited by this condition. The main contribution was the introduction of an additional block in the control loop that implements a new linear relationship between the duty cycle and the switching frequency in terms of the load current. This block proportionally modifies the duty cycle with the switching frequency that, as usual, is used to regulate the output voltage. The structure of the contribution was obtained by exploiting the knowledge of the differential equations that describe the dynamical behavior of the topology. Although it was shown that this modification could be used regardless of the control scheme implemented for the operation of the converter, its usefulness was illustrated by presenting a modified implementation of a classical

P I

control scheme. It was shown via numerical evaluations that the robustness of the converter under classical

P I

control was drastically improved for both increases and decreases in the load value. From the implementation perspective, this contribution is attractive since it exhibits a simple structure and neither requires the use of auxiliary switches nor increases the cost of current solutions. Full article

(This article belongs to the Section Energy Systems)

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16 pages, 2976 KiB

Open AccessArticle

Optimizing Continuous Casting through Cyber–Physical System

by Krzysztof Regulski, Łukasz Rauch, Piotr Hajder, Krzysztof Bzowski, Andrzej Opaliński, Monika Pernach, Filip Hallo, Michał Piwowarczyk and Sebastian Kalinowski

Processes 2024, 12(8), 1761; https://doi.org/10.3390/pr12081761 - 20 Aug 2024

Viewed by 474

Abstract

This manuscript presents a model of a system implementing individual stages of production for long steel products resulting from rolling. The system encompasses the order registration stage, followed by production planning based on information about the billet inventory status, then offers the possibility [...] Read more.

This manuscript presents a model of a system implementing individual stages of production for long steel products resulting from rolling. The system encompasses the order registration stage, followed by production planning based on information about the billet inventory status, then offers the possibility of scheduling orders for the melt shop in the form of melt sequences, manages technological knowledge regarding the principles of sequencing, and utilizes machine learning and optimization methods in melt sequencing. Subsequently, production according to the implemented plan is monitored using IoT and vision tracking systems for ladle tracking. During monitoring, predictions of energy demand and energy consumption in LMS processes are made concurrently, as well as predictions of metal overheating at the CST station. The system includes production optimization at two levels: optimization of the heat sequence and at the production level through the prediction of heating time. Optimization models and machine learning tools, including mainly neural networks, are utilized. The system described includes key components: optimization models for sequencing heats using Ant Colony Optimization (ACO) algorithms and neural network-based prediction models for power-on time. The manuscript mainly focuses on process modeling issues rather than implementation or deployment details. Machine learning models have significantly improved process efficiency and quality; the optimization of planning has reduced sequencing plan execution time; and power-on time prediction models estimate the main ladle heating time with 97% precision, enabling precise production control and reducing overheating. The system serves as an example of implementing the concept of a cyber–physical system. Full article

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

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17 pages, 2985 KiB

Open AccessArticle

Integration of Slurry–Total Reflection X-ray Fluorescence and Machine Learning for Monitoring Arsenic and Lead Contamination: Case Study in Itata Valley Agricultural Soils, Chile

by Guillermo Medina-González, Yelena Medina, Enrique Muñoz, Paola Andrade, Jordi Cruz, Yakdiel Rodriguez-Gallo and Alison Matus-Bello

Processes 2024, 12(8), 1760; https://doi.org/10.3390/pr12081760 - 20 Aug 2024

Viewed by 1021

Abstract

The accuracy of determining arsenic and lead using the optical technique Slurry–Total Reflection X-ray Fluorescence (Slurry-TXRF) was significantly enhanced through the application of a machine learning method, aimed at improving the ecological risk assessment of agricultural soils. The overlapping of the arsenic Kα [...] Read more.

The accuracy of determining arsenic and lead using the optical technique Slurry–Total Reflection X-ray Fluorescence (Slurry-TXRF) was significantly enhanced through the application of a machine learning method, aimed at improving the ecological risk assessment of agricultural soils. The overlapping of the arsenic Kα signal at 10.55 keV with the lead Lα signal at 10.54 keV due to the relatively low resolution of TXRF could compromise the determination of lead. However, by applying a Partial Least Squares (PLS) machine learning algorithm, we mitigated interference variations, resulting in improved selectivity and accuracy. Specifically, the average percentage error was reduced from 15.6% to 9.4% for arsenic (RMSEP improved from 5.6 mg kg⁻¹ to 3.3 mg kg⁻¹) and from 18.9% to 6.8% for lead (RMSEP improved from 12.3 mg kg⁻¹ to 5.03 mg kg⁻¹) compared to the previous univariable model. This enhanced predictive accuracy, within the set of samples concentration range, is attributable to the efficiency of the multivariate calibration first-order advantage in quantifying the presence of interferents. The evaluation of X-ray fluorescence emission signals for 26 different synthetic calibration mixtures confirmed these improvements, overcoming spectral interferences. Additionally, the application of these models enabled the quantification of arsenic and lead in soils from a viticultural subregion of Chile, facilitating the estimation of ecological risk indices in a fast and reliable manner. The results indicate that the contamination level of these soils with arsenic and lead ranges from moderate to considerable. Full article

(This article belongs to the Special Issue Solid and Hazardous Waste Disposal and Resource Utilization)

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17 pages, 3592 KiB

Open AccessArticle

Techno-Economic Analysis of Ethylene Adsorptive Separation Using Zeolite 13X in Oxidative Coupling of Methane Integrated Process

by Hamid Reza Godini, Nguyen Dang Huy, Lorenzo Ramponi, Nghiem Xuan Son, Babak Mokhtarani, Jens-Uwe Repke, Alberto Penteado, Giampaolo Manzolini, Alvaro Orjuela and Fausto Gallucci

Processes 2024, 12(8), 1759; https://doi.org/10.3390/pr12081759 - 20 Aug 2024

Viewed by 804

Abstract

Performance analysis of the adsorptive separation of ethylene downstream of an oxidative coupling of methane (OCM) process, being an alternative process for converting methane content of natural gas or other methane-rich sources to ethylene, was studied in this research for a production capacity [...] Read more.

Performance analysis of the adsorptive separation of ethylene downstream of an oxidative coupling of methane (OCM) process, being an alternative process for converting methane content of natural gas or other methane-rich sources to ethylene, was studied in this research for a production capacity of 1 Mt/yr. This was motivated by observing promising adsorption characteristics and efficiency in the selective adsorption of ethylene using 13X zeolite-based sorbent. The energy and economic performance of alternative scenarios for retrofitting the adsorption unit into an integrated OCM process were analyzed. Simulations of the integrated OCM process scenarios include OCM unit, CO₂-hydrogenation, ethane dehydrogenation and methane reforming sections. The use of efficient ethylene adsorption separation enabled the improvement of the economic and energy efficiency of the integrated OCM process under specific operating conditions. For instance, the invested amount of energy and the associated energy cost per ton of ethylene in the cryogenic ethylene-purification section of the integrated process using adsorption unit are, respectively, 75% and 89% lower than the reference integrated OCM process. Under the conditions considered in this analysis, the return on investment for the final proposed integrated OCM process structure using adsorption separation was found to be less than 9 years, and the potential for further improvement was also discussed. Full article

(This article belongs to the Special Issue Industrial Chemistry Reactions (3rd Edition): Kinetics, Mass and Heat Transfer in View of the Industrial Reactors Design)

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25 pages, 5717 KiB

Open AccessArticle

Selection and Optimization of China’s Energy Transformation Pathway Under Carbon-Neutral Targets

by Yingying Qi and Guohua Yu

Processes 2024, 12(8), 1758; https://doi.org/10.3390/pr12081758 - 20 Aug 2024

Viewed by 650

Abstract

This paper uses a bottom-up national energy technology model to study the optimization of China’s energy transformation pathway. The model clarifies specific action plans for China’s energy transformation pathway from 2020 to 2060, total carbon emissions, industry emission reduction responsibilities, and other dimensions. [...] Read more.

This paper uses a bottom-up national energy technology model to study the optimization of China’s energy transformation pathway. The model clarifies specific action plans for China’s energy transformation pathway from 2020 to 2060, total carbon emissions, industry emission reduction responsibilities, and other dimensions. The results show that: (1) The proportion of renewable energy consumption in China’s entire energy system from 2020 to 2060 will gradually exceed that of fossil energy under ideal circumstances, and the energy system will transition from traditional fossil energy to renewable energy. Meanwhile, the proportion of low-carbon energy sources, such as renewable energy, in primary energy demand will jump from 15.9% in 2020 to over 80% by 2060. (2) China’s CO₂ emissions will be approximately 3 billion tons, 2 billion tons, and 1 billion tons under three different socio-economic development scenarios of low, medium, and high speed in 2060. At that time, China will still need to absorb CO₂ through carbon sinks in forests, oceans, and wetlands. (3) The electricity industry has the highest CO₂ emissions compared to other industries. The electricity industry must bear significant responsibility for carbon reduction in future energy transformation and economic development. Full article

(This article belongs to the Section Energy Systems)

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13 pages, 11761 KiB

Open AccessArticle

Effects of Autogenous Gas Tungsten Arc Welding (GTAW) on Corrosion Resistance of Stainless Steel 316L

by Inyoung Song, Gwang-Ho Jeong, Sang-Kyo Kim, Yun Hwan Kim, Anthony B. Murphy, Tae-Kook Park, Ducklae Kim, Hyunwoo Park and Dae-Won Cho

Processes 2024, 12(8), 1757; https://doi.org/10.3390/pr12081757 - 20 Aug 2024

Viewed by 809

Abstract

The autogenous manual gas tungsten arc welding (GTAW) process was used for cladding austenitic stainless steel 316L using a single pass with various contact tip-to-work distances (CTWDs). Immersion and electrochemical tests were used to evaluate the corrosion resistance of the welded specimens, and [...] Read more.

The autogenous manual gas tungsten arc welding (GTAW) process was used for cladding austenitic stainless steel 316L using a single pass with various contact tip-to-work distances (CTWDs). Immersion and electrochemical tests were used to evaluate the corrosion resistance of the welded specimens, and a microstructural analysis was conducted to investigate the chemical composition of the molten pool and the heat-affected zone of welding. The key findings of this study indicate that the corrosion resistance improved under a CTWD of 5 mm due to the optimal distribution of ferrite and a refined microstructure. Additionally, the highest hardness was observed in specimens with a CTWD of 3 mm, attributed to the increased ferrite content in the weld metal. As the CTWD increased, the ferrite fraction decreased, and the hardness also diminished. However, in the CTWD 7 mm case, the higher heat input influenced the microstructure and molten pool shape significantly through the Marangoni effect, resulting in a lower corrosion resistance. These results suggest that optimizing the CTWD can enhance the corrosion resistance of welded 316L stainless steel. Full article

(This article belongs to the Section Materials Processes)

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14 pages, 2250 KiB

Open AccessArticle

Optimal Operation Strategy for Wind–Photovoltaic Power-Based Hydrogen Production Systems Considering Electrolyzer Start-Up Characteristics

by Ben Ma, Jianfeng Zheng, Zhongye Xian, Bo Wang and Hengrui Ma

Processes 2024, 12(8), 1756; https://doi.org/10.3390/pr12081756 - 20 Aug 2024

Viewed by 753

Abstract

Combining electrolytic hydrogen production with wind–photovoltaic power can effectively smooth the fluctuation of power and enhance the schedulable wind–photovoltaic power, which provides an effective solution to solve the problem of wind–photovoltaic power accommodation. In this paper, the optimization operation strategy is studied for [...] Read more.

Combining electrolytic hydrogen production with wind–photovoltaic power can effectively smooth the fluctuation of power and enhance the schedulable wind–photovoltaic power, which provides an effective solution to solve the problem of wind–photovoltaic power accommodation. In this paper, the optimization operation strategy is studied for the wind–photovoltaic power-based hydrogen production system. Firstly, to make up for the deficiency of the existing research on the multi-state and nonlinear characteristics of electrolyzers, the three-state and power-current nonlinear characteristics of the electrolyzer cell are modeled. The model reflects the difference between the cold and hot starting time of the electrolyzer, and the linear decoupling model is easy to apply in the optimization model. On this basis, considering the operation constraints of the electrolyzer, hydrogen storage tank, battery, and other equipment, the optimization operation model of the wind–photovoltaic power-based hydrogen production system is developed based on the typical scenario approach. It also considers the cold and hot starting time of the electrolyzer with the daily operation cost as the goal. The results show that the operational benefits of the system can be improved through the proposed strategy. The hydrogen storage tank capacity will have an impact on the operation income of the wind–solar hydrogen coupling system, and the daily operation income will increase by 0.32% for every 10% (300 kg) increase in the hydrogen storage tank capacity. Full article

(This article belongs to the Special Issue Sustainable and Intelligent Energy Systems and Processes: Recent Advances and Challenges)

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25 pages, 3591 KiB

Open AccessArticle

Predicting Petroleum SARA Composition from Density, Sulfur Content, Flash Point, and Simulated Distillation Data Using Regression and Artificial Neural Network Techniques

by Ivelina Shiskova, Dicho Stratiev, Sotir Sotirov, Evdokia Sotirova, Rosen Dinkov, Iliyan Kolev, Denis D. Stratiev, Svetoslav Nenov, Simeon Ribagin, Krassimir Atanassov, Dobromir Yordanov and Frans van den Berg

Processes 2024, 12(8), 1755; https://doi.org/10.3390/pr12081755 - 20 Aug 2024

Viewed by 864

Abstract

The saturate, aromatic, resin, and asphaltene content in petroleum (SARA composition) provides valuable information about the chemical nature of oils, oil compatibility, colloidal stability, fouling potential, and other important aspects in petroleum chemistry and processing. For that reason, SARA composition data are important [...] Read more.

The saturate, aromatic, resin, and asphaltene content in petroleum (SARA composition) provides valuable information about the chemical nature of oils, oil compatibility, colloidal stability, fouling potential, and other important aspects in petroleum chemistry and processing. For that reason, SARA composition data are important for petroleum engineering research and practice. Unfortunately, the results of SARA composition measurements reported by diverse laboratories are frequently very dissimilar and the development of a method to assign SARA composition from oil bulk properties is a question that deserves attention. Petroleum fluids with great variability of SARA composition were employed in this study to model their SARA fraction contents from their density, flash point, sulfur content, and simulated distillation characteristics. Three data mining techniques: intercriteria analysis, regression, and artificial neural networks (ANNs) were applied. It was found that the ANN models predicted with higher accuracy the contents of resins and asphaltenes, whereas the non-linear regression model predicted most accurately the saturate fraction content but with an accuracy that was lower than that reported in the literature regarding uncertainty of measurement. The aromatic content was poorly predicted by all investigated techniques, although the prediction of aromatic content was within the uncertainty of measurement. The performed study suggests that as well as the investigated properties, additional characteristics need to be explored to account for complex petroleum chemistry in order to improve the accuracy of SARA composition prognosis. Full article

(This article belongs to the Special Issue Technological Processes for Chemical and Related Industries)

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27 pages, 17532 KiB

Open AccessArticle

Physical Properties of High-Rank Coal Reservoirs and the Impact on Coalbed Methane Production

by Gang Liu, Runchi Tang, Chi Mu, Xing Liu and Junjian Zhang

Processes 2024, 12(8), 1754; https://doi.org/10.3390/pr12081754 - 20 Aug 2024

Viewed by 575

Abstract

The physical characteristics of coal reservoirs are important factors affecting the occurrence status of coalbed methane, as well as key factors restricting the production capacity. Therefore, taking 3# coal in Qinnan region of China as the research object, based on the actual production [...] Read more.

The physical characteristics of coal reservoirs are important factors affecting the occurrence status of coalbed methane, as well as key factors restricting the production capacity. Therefore, taking 3# coal in Qinnan region of China as the research object, based on the actual production data of 200 coalbed methane wells in the research area, experimental testing combined with simulation analysis was used to explore the physical properties of medium and high-order reservoirs and their impact on the occurrence and production of coalbed methane. The characteristics of coalbed methane reservoir formation and production capacity changes in the research area were revealed, and the factors restricting the production capacity of coalbed methane wells were calculated using the gray correlation analysis method. The results indicate that the micropores in the coal reservoir in the study area are well-developed, while the macropores and mesopores (exogenous fractures) are underdeveloped, the surface of the micropores is complex, and the connectivity of the micropores is poor, resulting in reservoirs with high gas adsorption characteristics and low permeability. The fractal characteristics of pores and fractures can reflect the permeability characteristics of reservoirs. Permeability is positively correlated with macropores (exogenous fractures) and mesopores, and negatively correlated with micropores. There is a positive correlation between permeability and productivity, and the reservoir in the study area has a stress-sensitive boundary. The main factors restricting productivity under the complex pore and fracture system of high-rank coal reservoir were identified, and the gray relational analysis method was used to evaluate the development effect of the research area. This study provides guidance for the development of coalbed methane production in high-rank coal reservoirs. Full article

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

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13 pages, 2820 KiB

Open AccessArticle

Research and Application for Alternate Production Technology of Dual-Branch Horizontal Wells in an Offshore Oilfield

by Dong Zhang, Fenghui Li, Yanlai Li, Xu Zheng, Chunyan Liu, Hongjie Liu and Xiang Wang

Processes 2024, 12(8), 1753; https://doi.org/10.3390/pr12081753 - 20 Aug 2024

Viewed by 574

Abstract

Old-well sidetracking is a key method for controlling low-productivity wells in the Bohai oilfield. This study employs reservoir engineering and numerical simulation techniques to investigate the maximum drainage radius and natural coning control mechanism in heavy-oil reservoirs with bottom water. Based on these [...] Read more.

Old-well sidetracking is a key method for controlling low-productivity wells in the Bohai oilfield. This study employs reservoir engineering and numerical simulation techniques to investigate the maximum drainage radius and natural coning control mechanism in heavy-oil reservoirs with bottom water. Based on these findings, an alternate production technology was developed for dual-branch horizontal wells. The technology creates a new branch through sidetracking, connecting and isolating the old and new wellbores using a combination of wall hangers and branch guides. Initially, the old wellbore with an ultra-high water cut is temporarily sealed. When the new branch reaches a high water-cut stage, production is switched back to the old wellbore. This technology was successfully applied to three wells in the Bohai oilfield, resulting in the new branch achieving expected production levels, while reopening the old wellbore increased daily oil output by 27 m³ and reduced water cut by 5.6%. Cumulative oil production from these wells reached 95,000 m³. This technology improves well-slot resource utilization, enhances recovery rates, and has significant potential for broader application. Full article

(This article belongs to the Special Issue Modeling, Control, and Optimization of Drilling Techniques)

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21 pages, 3596 KiB

Open AccessArticle

Residue from Passion Fruit Processing Industry: Application of Mathematical Drying Models for Seeds

by Mario Eduardo R. M. Cavalcanti-Mata, Maria Elita Martins Duarte, Francisco de Assis Mendes, Manoel Tolentino Leite Filho, Rafaela Duarte Almeida, Anna Sylvia R. R. M. Cavalcanti and Renata Duarte Almeida

Processes 2024, 12(8), 1752; https://doi.org/10.3390/pr12081752 - 20 Aug 2024

Viewed by 575

Abstract

The objective of this research was to study the drying kinetics of passion fruit seeds, a byproduct of the industrial processing of passion fruit with the potential to elaborate food products such as oil and flour. After drying, the seeds were directed for [...] Read more.

The objective of this research was to study the drying kinetics of passion fruit seeds, a byproduct of the industrial processing of passion fruit with the potential to elaborate food products such as oil and flour. After drying, the seeds were directed for cold press oil extraction, and the quantification of fatty acids was performed. Following the oil extraction, the residues underwent a grinding process to produce flour, which was characterized in terms of its nutritional aspects. The drying process was conducted using an experimental forced convection dryer with controlled temperatures of 40, 50, 60, and 70 °C, and a drying air velocity of 1.5 m s⁻¹. This work introduced a novel approach using mathematical models, all derived from Fick’s equation. For each model, the activation energy and thermodynamic properties related to the drying procedure were determined. Fatty acids in the oils and physicochemical characteristics of the defatted residue’s flour were also analyzed. The Cavalcanti Mata, Henderson and Pabis, and Page models modified by Cavalcanti Mata were found to best fit the experimental data. The highest proportions of unsaturated fatty acids in passion fruit oil were linoleic acid (Omega-6) at 68.8% and oleic acid (Omega-9) at 16.1%. The predominant saturated fatty acid was palmitic acid at 10.61%, with no significant differences observed in relation to the drying temperatures. It can be concluded that the composition of the flour from the residue of passion fruit grain oil extraction varies in terms of crude fiber content, ranging from 56.36% to 58.8%, and protein content, ranging from 15.6% to 18.26%, with significant differences observed concerning the drying temperatures. The lipid content varied from 13.5% to 13.76%, with no significant differences observed across the evaluated drying temperature variations. Full article

(This article belongs to the Special Issue Transport Processes in Porous Material and Porous Media: Latest Developments and New Approaches)

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