Processes

16 pages, 2567 KiB

Open AccessArticle

A Predictive Model for Sintering Ignition Temperature Based on a CNN-LSTM Neural Network with an Attention Mechanism

by Da-Lin Xiong, Hou-Yin Ning, Meng Xie, Cong-Yuan Pan, Liang-Jun Chen, Zheng-Wei Yu and Hong-Ming Long

Processes 2024, 12(10), 2185; https://doi.org/10.3390/pr12102185 - 8 Oct 2024

Abstract

The sintering ignition process parameters fluctuate frequently and significantly, resulting in large variations in ignition temperature, which in severe cases can exceed 200 °C. This not only increases gas consumption but also affects the quality of the sinter. Because the intelligent control model [...] Read more.

The sintering ignition process parameters fluctuate frequently and significantly, resulting in large variations in ignition temperature, which in severe cases can exceed 200 °C. This not only increases gas consumption but also affects the quality of the sinter. Because the intelligent control model based on feedback mechanisms struggles to deal with high-frequency fluctuation conditions over time, the prediction of sintering ignition temperature using feedforward regulation is attracting increasing attention. Given the multi-variable, time-sequential and strongly coupled characteristics of the sintering ignition process, a convolutional neural network (CNN) and a long short-term memory (LSTM) network are deeply integrated, with an attention mechanism incorporated to develop the sintering ignition temperature prediction model, enabling the accurate prediction of the ignition temperature. The research demonstrates that the combination of a CNN and the attention mechanism effectively addresses the challenges posed by the multi-variable and strongly coupled nature of sintering ignition data to predictive modeling. The LSTM network resolves the sequential data issues through its gating mechanism. As a result, the coefficient of determination () of the CNN_LSTM-Attention model in predicting the sintering ignition temperature can reach 0.97, with a mean absolute error () as low as 10.23 °C. The predicted values closely match the actual values, achieving a hit rate of 93% within the acceptable error range. These performance metrics are significantly superior to those of the CNN-Attention and LSTM-Attention models, greatly enhancing the control accuracy of the ignition temperature. Full article

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

15 pages, 871 KiB

Open AccessArticle

Intelligent Lost Circulation Monitoring Method Based on Data Augmentation and Temporal Models

by Detao Zhou, Chenzhan Zhou, Ziyue Zhang, Mengmeng Zhou, Chengkai Zhang, Lin Zhu, Qihao Li and Chaochen Wang

Processes 2024, 12(10), 2184; https://doi.org/10.3390/pr12102184 - 8 Oct 2024

Abstract

Deep and offshore drilling operations face complex geological formations, uncertain formation pressures, and narrow safety density windows, making them susceptible to lost circulation risks. To address these challenges, this paper introduces an innovative, intelligent lost circulation monitoring model that incorporates geological lithology information. [...] Read more.

Deep and offshore drilling operations face complex geological formations, uncertain formation pressures, and narrow safety density windows, making them susceptible to lost circulation risks. To address these challenges, this paper introduces an innovative, intelligent lost circulation monitoring model that incorporates geological lithology information. This model not only utilizes real-time drilling parameters, but also encodes geological information such as rock type as inputs to the model. By combining these key lithological features, the model can comprehensively assess wellbore stability and reduce the lost circulation risks. In this paper, the Conditional Tabular Generative adversarial network (CTGAN) model is used to enhance the data of small-sample risk data, which can effectively expand the data distribution space and improve the performance of the model. This paper conducts a comparative analysis of intelligent monitoring results using artificial neural networks (ANNs), long short-term memory (LSTM), and temporal convolutional networks (TCNs). The results show that the TCN achieves an identification accuracy of 93.7%. Furthermore, the analysis reveals that the inclusion of lithology information significantly enhances the model’s performance, resulting in a 7.1% increase in accuracy. The false alarm rate of the model can be reduced by 10.2%, considering the fluctuation of the logging curve caused by the on/off condition of the pump . This indicates that the introduction of lithology information and the condition of the pump on−off provide advantages in monitoring and identifying lost circulation risks, enabling a more precise assessment of wellbore stability and a reduction in lost circulation incidents. The method of lost circulation monitoring proposed in this paper provides an important safety guarantee for the oil drilling industry. Full article

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

21 pages, 1560 KiB

Open AccessArticle

Experimental and CFD Analysis of Hydrodynamics in Dual-Impeller Crystallizer at Different Off-Bottom Clearances

by Antonija Čelan, Marija Ćosić, Željko Penga and Nenad Kuzmanić

Processes 2024, 12(10), 2183; https://doi.org/10.3390/pr12102183 - 8 Oct 2024

Abstract

Producing tailor-made crystals demands knowledge of the influence of hydrodynamics and nucleation kinetics. In this paper, the hydrodynamic conditions in a dual-impeller crystallizer and their influence on the key nucleation parameters of the batch cooling crystallization of borax at different impeller off-bottom clearances [...] Read more.

Producing tailor-made crystals demands knowledge of the influence of hydrodynamics and nucleation kinetics. In this paper, the hydrodynamic conditions in a dual-impeller crystallizer and their influence on the key nucleation parameters of the batch cooling crystallization of borax at different impeller off-bottom clearances were investigated. Two different impeller configurations were used—a dual pitched-blade turbine (2 PBT) and a dual straight-blade turbine (2 SBT). Hydrodynamics was analyzed in depth based on the developed computational fluid dynamics model. The experimental results on mixing time and power input were used to validate the numerical model. The results show that the properties of the final product are affected by the impeller position in both dual-impeller configurations. An increase in the impeller off-bottom clearance in both systems results in a decrease in the mean crystal size. The hydrodynamic conditions generated at C/D = 1 in the 2 PBT impeller system and at C/D = 0.6 in the 2 SBT impeller system favored an earlier onset of nucleation compared to other impeller positions. It was found that the eddy dissipation rate and the Kolmogorov length scale correlate highly with the mean crystal size, suggesting that the size is affected by the shear stress in the vessel, rather than the overall convective flow. Full article

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

20 pages, 13022 KiB

Open AccessFeature PaperReview

Safety of Hydrogen Storage Technologies

by Emma Davies, Andrea Ehrmann and Eva Schwenzfeier-Hellkamp

Processes 2024, 12(10), 2182; https://doi.org/10.3390/pr12102182 - 8 Oct 2024

Abstract

While hydrogen is regularly discussed as a possible option for storing regenerative energies, its low minimum ignition energy and broad range of explosive concentrations pose safety challenges regarding hydrogen storage, and there are also challenges related to hydrogen production and transport and at [...] Read more.

While hydrogen is regularly discussed as a possible option for storing regenerative energies, its low minimum ignition energy and broad range of explosive concentrations pose safety challenges regarding hydrogen storage, and there are also challenges related to hydrogen production and transport and at the point of use. A risk assessment of the whole hydrogen energy system is necessary to develop hydrogen utilization further. Here, we concentrate on the most important hydrogen storage technologies, especially high-pressure storage, liquid hydrogen in cryogenic tanks, methanol storage, and salt cavern storage. This review aims to study the most recent research results related to these storage techniques by describing typical sensors and explosion protection measures, thus allowing for a risk assessment of hydrogen storage through these technologies. Full article

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

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19 pages, 7417 KiB

Open AccessArticle

Study on the Performance of a Novel Double-Section Full-Open Absorption Heat Pump for Flue Gas Waste Heat Recovery

by Xin Cai, Zhanbin Wang, Yuhao Han and Wei Su

Processes 2024, 12(10), 2181; https://doi.org/10.3390/pr12102181 - 8 Oct 2024

Abstract

Open absorption heat pumps are considered one of the most promising methods for efficiently utilizing low-grade waste heat, reducing energy consumption, and lowering greenhouse gas emissions. However, traditional heat pumps have significant limitations in the range of flue gas temperatures they can recover, [...] Read more.

Open absorption heat pumps are considered one of the most promising methods for efficiently utilizing low-grade waste heat, reducing energy consumption, and lowering greenhouse gas emissions. However, traditional heat pumps have significant limitations in the range of flue gas temperatures they can recover, and their relatively low system performance further restricts practical applications. In this study, we propose a novel double-section full-open absorption heat pump driven by flue gas from the desulfurization tower. By designing the absorber with a double-layer structure, the system can recover more latent and sensible heat from the flue gas, significantly enhancing its thermal recovery capability. Additionally, replacing the traditional LiBr/H₂O working pair with LiCl/H₂O significantly reduces the risks of solution crystallization and equipment corrosion. Through comprehensive research, the strengths and weaknesses of the system were explored. The results indicate that this system effectively recovers flue gas waste heat within the temperature range of 30–70 °C. Specifically, at a flue gas temperature of 70 °C and a flow rate of 3 kg/s, the system achieves a COP of 1.838, along with a heating capacity of 158.83 kW and a ROI of 34.1%. These metrics demonstrate that the system not only delivers high performance but also exhibits excellent economic viability. Additionally, when the solution temperature is lowered to 10 °C, the system’s maximum COP reaches 1.96, reflecting a significant 30.67% improvement over traditional heat pumps. These findings highlight the system’s potential for application in coal-fired power plants, where varying levels of power output can benefit from enhanced thermal recovery and efficiency. Full article

(This article belongs to the Special Issue Model Predictive Control of Heating and Cooling Systems)

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37 pages, 6694 KiB

Open AccessReview

Sustainable Drilling Fluids: A Review of Nano-Additives for Improved Performance and Reduced Environmental Impact

by Maaly Salah Asad, Mohammed Thamer Jaafar, Farhan Lafta Rashid, Hussein Togun, Musaab K. Rasheed, Mudhar A. Al-Obaidi, Qusay Rasheed Al-Amir, Hayder I. Mohammed and Ioannis E. Sarris

Processes 2024, 12(10), 2180; https://doi.org/10.3390/pr12102180 - 8 Oct 2024

Abstract

The implication of nano-additives in drilling fluids introduces a promising avenue for enhancing sustainability in the oil and gas industry. By upgrading the properties of drilling fluids, nano-additives can contribute to mitigating the drilling costs, improving wellbore stability, and minimizing the environmental impact. [...] Read more.

The implication of nano-additives in drilling fluids introduces a promising avenue for enhancing sustainability in the oil and gas industry. By upgrading the properties of drilling fluids, nano-additives can contribute to mitigating the drilling costs, improving wellbore stability, and minimizing the environmental impact. For example, the use of nano-additives can diminish the amount of drilling fluid required, thus reducing the volume of waste generated. Also, nano-additives can enhance the efficacy of drilling operations, leading to reduced energy consumption and greenhouse gas emissions. This review researches the potential of nano-additives in enhancing sustainable drilling practices, emphasizing the environmental advantages and economic advantages associated with their usage. Specifically, this comprehensive review will elucidate the most recent developments in drilling fluids by evaluating the impact of nano-additives. Referring to the conclusions, adding nanoparticles to drilling fluids significantly improves their characteristics. At 0.2 parts per billion (ppb), for example, the yield stress increases by 36% and the plastic viscosity increases by 17%. In addition, the inclusion of nanoparticles at a concentration of 0.6 ppb led to a significant decrease of 60% in the loss of filtrate. The measured enhancements highlight the capacity of nano-additives to augment the properties of drilling fluid, necessitating additional investigation into their prospective applications for enhancing competitiveness in the gas and oil industry. This study methodically examines the effects of these breakthroughs on scientific, commercial, and industrial sectors. It intends to provide an inclusive understanding of the possible advantages of nano-additives in drilling operations. Full article

(This article belongs to the Special Issue Advances in Renewable and Sustainable Engineering from the 5th International Conference on Sustainable Engineering Techniques)

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21 pages, 4971 KiB

Open AccessArticle

Fault Location Method of Distribution Network Based on VGAE-GraphSAGE

by Min Fan, Jialu Xia, Huanjiao Zhang and Xi Zhang

Processes 2024, 12(10), 2179; https://doi.org/10.3390/pr12102179 - 7 Oct 2024

Abstract

The distribution network is the main component of the power system, which undertakes the important function of power transmission and distribution. Fast and accurate distribution network fault location is one of the important means to ensure the safe and stable operation of the [...] Read more.

The distribution network is the main component of the power system, which undertakes the important function of power transmission and distribution. Fast and accurate distribution network fault location is one of the important means to ensure the safe and stable operation of the power system and is helpful in guiding troubleshooting, shortening the power outage time, reducing the workload of manual inspection, and reducing the social and economic losses caused by faults. Due to the development of the new distribution network, the comprehensive influence of many factors has put forward new challenges to the traditional distribution network fault location methods. In this paper, a distribution network fault location method based on the graph neural network is proposed. Firstly, the distribution network is treated as non-Euclidean graph data; secondly, variational graph auto-encoders (VGAE) are used to mine the underlying information of nodes and improve the overall anti-noise performance of the fault location method. Then the GraphSAGE model is used to aggregate the neighbor information of nodes, fully consider the influence of the surrounding lines on the target lines, and improve the output of the model to locate the distribution network line where the fault occurred. The experimental example analysis based on OpenDSS simulation software (version 9.8) proves that the proposed method has high accuracy and anti-interference, and the accuracy reached 97.81%. Moreover, the positioning result is still good in the new intelligent distribution network scenario with distributed power access, with an accuracy of 95.07% in the hybrid power generation scenario. Full article

(This article belongs to the Section Automation Control Systems)

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18 pages, 2295 KiB

Open AccessArticle

Piperazine-Based Mixed Solvents for CO₂ Capture in Bubble-Column Scrubbers and Regeneration Heat

by Pao-Chi Chen, Jyun-Hong Jhuang and Zhong-Yi Lin

Processes 2024, 12(10), 2178; https://doi.org/10.3390/pr12102178 - 7 Oct 2024

Abstract

This work used piperazine (PZ) as a base solvent, blended individually with five amines, which were monoethanolamine (MEA), secondary amines (DIPAs), tertiary amines (TEAs), stereo amines (AMPs), and diethylenetriamine (DETA), to prepare mixed solvents at the desired concentrations as the test solvents. A [...] Read more.

This work used piperazine (PZ) as a base solvent, blended individually with five amines, which were monoethanolamine (MEA), secondary amines (DIPAs), tertiary amines (TEAs), stereo amines (AMPs), and diethylenetriamine (DETA), to prepare mixed solvents at the desired concentrations as the test solvents. A continuous bubble-column scrubber with one stage (1 s) was first used for the test. Six parameters were selected, including the type of mixed solvent (A), the ratio of mixed solvents (B), the solvent feed rate (C), the gas flow rate (D), the concentration of the mixed solvents (E), and the liquid temperature (F), each one having five levels. Using the Taguchi experimental design, only 25 runs were required. The outcome data, such as the absorption efficiency (E_F), the absorption rate (R_A), the overall mass-transfer coefficient (K_Ga), and the absorption factor (φ), could be determined under steady-state conditions. The optimal mixed solvents were found to be A1 (PZ + MEA) and A2 (PZ + DIPA). The parameter importance and optimal conditions for E_F, R_A, K_Ga, and ϕ were determined separately; the verification of all optimal conditions was successful. This analysis found that the importance of the parameters was D > C > A > E > B > F, and the gas flow rate (D) was the most important factor. Subsequently, multiple-stage scrubbers were used to capture CO₂. Comparing 1 s and 3 s (three-stage scrubber), E_F, R_A, K_Ga, and φ increased by 33%, 29%, 22%, and 38%, respectively. The desorption tests for the four optimal scrubbed solutions, including multiple stages, showed that the heat of regeneration for the three scrubbers was 3.57–8.93 GJ/t, in the temperature range of 110–130 °C, while A2 was the best solvent. Finally, the heat regeneration mechanism was also discussed in this work. Full article

(This article belongs to the Special Issue Recent Advances in Modern Carbon-Negative Technologies for CO₂ Capture)

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30 pages, 1400 KiB

Open AccessReview

Cardiovascular Drugs as Water Contaminants and Analytical Challenges in the Evaluation of Their Degradation

by Aleksander Kravos, Andreja Žgajnar Gotvajn and Helena Prosen

Processes 2024, 12(10), 2177; https://doi.org/10.3390/pr12102177 - 7 Oct 2024

Abstract

Cardiovascular drugs have been a burning topic in the field of environmental analytical chemistry in the last few decades. Growing modern healthcare has led to the widespread use of pharmaceuticals. Among these, antihypertensives (sartans, angiotensin-converting enzyme inhibitors) and lipid-regulating drugs (fibrates and statins) [...] Read more.

Cardiovascular drugs have been a burning topic in the field of environmental analytical chemistry in the last few decades. Growing modern healthcare has led to the widespread use of pharmaceuticals. Among these, antihypertensives (sartans, angiotensin-converting enzyme inhibitors) and lipid-regulating drugs (fibrates and statins) are the most frequently consumed and, thus, excreted into wastewater. Their chemical fate during conventional and advanced wastewater treatment, such as ozonation, remains unclear. Analytical chemistry, providing sample pretreatment followed by instrumental analysis, has a tremendous role in water treatment evaluation, mostly from the perspective of parent contaminants’ removals and also assessment of transformation pathways. Ultrasensitive liquid chromatography–mass spectrometry (LC-MS) systems provide many opportunities. By carefully using planned workflows for chromatographic and mass-spectrometric data processing, i.e., suspect and non-target screening approaches, LC-MS allows for the identification and structural elucidation of unknown, predicted, suspected or selected transformation products. Accordingly, some examples and case studies on selected cardiovascular drugs in this review are presented to show the applicability of the used analytical approaches and workflows. Full article

(This article belongs to the Special Issue Municipal Wastewater Treatment and Removal of Micropollutants)

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15 pages, 5424 KiB

Open AccessArticle

Evaluation of CO₂/Water Imbibition Relative Permeability Curves in Sandstone Core Flooding—A CFD Study

by Tathagata Acharya, Tapinder Dhaliwal, Alina Ludian, Gorang Popli, Benjamin Wilemon, Leonardo Hernandez, Maryam Farahani and Liaosha Song

Processes 2024, 12(10), 2176; https://doi.org/10.3390/pr12102176 - 7 Oct 2024

Abstract

Greenhouse gases such as CO₂ can be safely captured and stored in geologic formations, which in turn can reduce the carbon imprint in the Earth’s atmosphere and therefore help toward reducing global warming. The relative permeability characteristics in CO₂/brine or [...] Read more.

Greenhouse gases such as CO₂ can be safely captured and stored in geologic formations, which in turn can reduce the carbon imprint in the Earth’s atmosphere and therefore help toward reducing global warming. The relative permeability characteristics in CO₂/brine or CO₂/water systems provide insight into the CO₂ trapping efficacy of formations such as sandstone rocks. In this research, CO₂/water imbibition relative permeability characteristics in a typical sandstone core sample are numerically evaluated. This work uses transient computational fluid dynamics (CFD) simulations to study relative permeability characteristics, and a sensitivity analysis is performed based on two different injection pressures and absolute permeability values of the sandstone rock material. Results show that when the irreducible water fraction remains unchanged, the imbibition relative permeability to the non-wetting phase decreases with an increase in injection pressure within the sandstone core sample. Also, with the irreducible water fraction being unchanged, relative permeabilities to both non-wetting and wetting phases decrease with an increase in the absolute permeability of the rock material. Finally, at irreducible water saturation, relative permeability to the gas phase decreases with an increase in injection pressure. Full article

(This article belongs to the Special Issue Thermal and Fluid Flow Processes in Sustainable and Conventional Energy)

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16 pages, 5727 KiB

Open AccessFeature PaperArticle

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

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

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

Abstract

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

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

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

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13 pages, 4598 KiB

Open AccessArticle

The Transformative Role of Nano-SiO₂ in Polymer Electrolytes for Enhanced Energy Storage Solutions

by S. Jayanthi, M. Vahini, S. Karthickprabhu, A. Anusuya, N. Karthik, K. Karuppasamy, Tholkappiyan Ramachandran, A. Nichelson, M. Mahendran, B. Sundaresan and Dhanasekaran Vikraman

Processes 2024, 12(10), 2174; https://doi.org/10.3390/pr12102174 - 7 Oct 2024

Abstract

In lithium–polymer batteries, the electrolyte is an essential component that plays a crucial role in ion transport and has a substantial impact on the battery’s overall performance, stability, and efficiency. This article presents a detailed study on developing nanostructured composite polymer electrolytes (NCPEs), [...] Read more.

In lithium–polymer batteries, the electrolyte is an essential component that plays a crucial role in ion transport and has a substantial impact on the battery’s overall performance, stability, and efficiency. This article presents a detailed study on developing nanostructured composite polymer electrolytes (NCPEs), prepared using the solvent casting technique. The materials selected for this investigation include poly(vinyl chloride) (PVC) as the host polymer, lithium bromide (LiBr) as the salt, and silica (SiO₂) as the nanofiller. The addition of nano-SiO₂ dramatically enhanced the ionic conductivity of the electrolytes, with the highest value of 6.2 × 10⁻⁵ Scm⁻¹ observed for the sample containing 7.5 wt% nano-SiO₂. This improvement is attributed to an increased amorphicity resulting from the interactions between the polymer, salt, and filler components. A structural analysis of the prepared NCPEs using X-ray diffraction revealed the presence of both crystalline and amorphous phases, further validating the enhanced ionic transport. Additionally, the thermal stability of the NCPEs was found to be excellent, withstanding temperatures up to 334 °C, thereby reinforcing their potential application in lithium–polymer batteries. This work explores the electrochemical performance of a fabricated lithium-ion-conducting primary electrochemical cell (Zn + ZnSO₄·7H₂O|PVC: LiBr: SiO₂|PbO₂ + V₂O₅), which demonstrated an open circuit voltage of 2.15 V. The discharge characteristics of the fabricated cell were thoroughly studied, showcasing the promising potential of these NCPEs. With the support of superior morphological and electrical properties, as-prepared electrolytes offer an effective pathway for future advancements in lithium–polymer battery technology, making them a highly viable candidate for enhanced energy storage solutions. Full article

(This article belongs to the Special Issue High-Efficiency Nanomaterials Synthesis and Applications)

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19 pages, 8988 KiB

Open AccessArticle

CFD Analysis of the Effects of a Barrier in a Hydrogen Refueling Station Mock-Up Facility during a Vapor Cloud Explosion Using the radXiFoam v2.0 Code

by Hyung-Seok Kang, Keun-Sang Choi, Hyun-Woo Lee and Chul-Hee Yu

Processes 2024, 12(10), 2173; https://doi.org/10.3390/pr12102173 - 6 Oct 2024

Abstract

A CFD (computational fluid dynamics) analysis to investigate the effects of the installation of a barrier in a hydrogen refueling station (HRS) mock-up facility, with a dummy vehicle and dispensers in the vapor cloud region, during a hydrogen-air explosion using a gas mixture [...] Read more.

A CFD (computational fluid dynamics) analysis to investigate the effects of the installation of a barrier in a hydrogen refueling station (HRS) mock-up facility, with a dummy vehicle and dispensers in the vapor cloud region, during a hydrogen-air explosion using a gas mixture volume of 70.16 m³ was conducted to determine whether the radXiFoam v2.0 code with the established analysis methodology to predict the peak overpressure can be utilized to evaluate the safety of a HRS with such a barrier installed in a large city in the Republic of Korea. The radXiFoam v2.0 code was developed on the basis of the XiFoam solver in the open-source CFD software OpenFOAM-v2112 by modifying C++ source codes in several libraries and governing equations so as to ensure effective calculations of the hydrogen-air chemical reaction and radiative heat transfer through water vapor in a humid air environment and to remove unnecessary warning messages that arise when using the radXiFoam v1.0 code. First, we conducted a validation analysis on the basis of measured overpressure datasets from a near field to a far field of a vapor cloud explosion (VCE) site in the HRS mock-up facility to evaluate the uncertainty in prediction datasets by radXiFoam v2.0. After this validation analysis, we undertook CFD sensitivity calculations by installing barriers with heights of 2.1 m and 4.2 m at a horizontal distance of 2.3 m from the VCE region in the grid model used for the validation analysis to assess the effects of these barriers on reducing the peak overpressure of the blast wave. From these calculations, we judged that the radXiFoam v2.0 code can accurately simulate the effects of the barrier during a VCE, as the calculated overpressure reduction values according to the barrier height are reasonable on the basis of previous validation results from Stanford Research Institute’s explosion test with such a barrier. The results herein imply that the radXiFoam v2.0 code is feasible for use in HRS safety when barrier installation must meet the technical regulations of the Korea Gas Safety Corporation in a large city. Full article

(This article belongs to the Special Issue Applications of Computational Fluid Dynamics (CFD) in Chemical Process Simulations)

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17 pages, 5063 KiB

Open AccessArticle

Effect of Sewage Sludge Addition on the Co-Combustion Characteristics of Municipal Solid Waste Incineration

by Hao Wu, Lingxia Zhu, Jianjun Cai and Huijuan Lv

Processes 2024, 12(10), 2172; https://doi.org/10.3390/pr12102172 - 6 Oct 2024

Abstract

This study employs a numerical computation model based on a municipal solid waste (MSW) incinerator in Nanning to investigate the impact of different sewage sludge (SS) co-combustion ratios and MSW incinerator temperatures on combustion efficiency. Using the FLUENT simulation method, this study systematically [...] Read more.

This study employs a numerical computation model based on a municipal solid waste (MSW) incinerator in Nanning to investigate the impact of different sewage sludge (SS) co-combustion ratios and MSW incinerator temperatures on combustion efficiency. Using the FLUENT simulation method, this study systematically analyzes the distribution characteristics of the temperature field, velocity field, and pollutant concentration field within the furnace under various SS mixing ratios (5%, 7%, 10%, and 15%) and MSW incinerator temperatures (800 K, 1000 K, and 1200 K). The simulation results indicate that the combustion efficiency was optimal at an MSW incinerator temperature of 800 K, where the co-combustion of SS with MSW mixed effectively, leading to a stable and efficient combustion process. Furthermore, an SS co-combustion ratio of 7% was identified as the most effective in maintaining high combustion efficiency. These findings contribute to the optimization of co-combustion strategies for MSW and SS, enhancing both operational efficiency and environmental compliance. Full article

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

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29 pages, 3277 KiB

Open AccessArticle

Optimization of Synchronous Control Parameters Based on Improved Sinusoidal Gray Wolf Algorithm

by Taoyu Wang, Shiyan Sun and Bo She

Processes 2024, 12(10), 2171; https://doi.org/10.3390/pr12102171 - 5 Oct 2024

Abstract

High precision control is often accompanied by many control parameters, which are interrelated and difficult to adjust directly. It is difficult to convert the system control effect directly into mathematical expression, so it is difficult to optimize it by intelligent algorithm. To solve [...] Read more.

High precision control is often accompanied by many control parameters, which are interrelated and difficult to adjust directly. It is difficult to convert the system control effect directly into mathematical expression, so it is difficult to optimize it by intelligent algorithm. To solve this problem, we propose an improved sinusoidal gray wolf optimization algorithm (ISGWO). In this algorithm, a particle crossing processing mechanism based on the symmetry idea is introduced to maximize the retention of the position information of the optimal individual and improve the search accuracy of the algorithm. In addition, a differential cross-perturbation strategy is adopted to help the algorithm jump out of the local optimal solution in time, which enhances the development capability of ISGWO. Meanwhile, the position update formula with improved sinusoidal can better balance the development and exploration of ISGWO. The ISGWO algorithm is compared with three improved Gray Wolf algorithms on the CEC2017 test set as well as the synchronization controller. The experimental results show that the ISGWO algorithm has better selectivity, speed and robustness. Full article

(This article belongs to the Special Issue Modeling, Simulation, Control, and Optimization of Processes)

22 pages, 905 KiB

Open AccessArticle

Gas Chromatography Tandem Mass Spectrometry (GC-MS/MS) for High-Throughput Screening of Pesticides in Rice Samples Collected in Bangladesh and Saudi Arabia

by Ilya Strashnov, Farah T. Ahmed, May M. Alrashdi, Inna Nesmiyan and David A. Polya

Processes 2024, 12(10), 2170; https://doi.org/10.3390/pr12102170 - 5 Oct 2024

Abstract

Gas Chromatography Tandem Mass Spectrometry (GC-MS/MS) with modified QuEChERS sample preparation has been applied to the high-throughput screening of pesticide residuals in rice collected from Bangladesh and Saudi Arabia markets. Both countries consume high volumes of rice, which is a fundamental food for [...] Read more.

Gas Chromatography Tandem Mass Spectrometry (GC-MS/MS) with modified QuEChERS sample preparation has been applied to the high-throughput screening of pesticide residuals in rice collected from Bangladesh and Saudi Arabia markets. Both countries consume high volumes of rice, which is a fundamental food for their populations. We report optimized sample preparation and mass spectrometry analysis protocols, which can be rapidly deployed in analytical laboratories. The screening of four groups (organophosphorus, synthetic pyrethroid, organonitrogen, and organochlorine) of a total of 115 pesticides can be performed within ~10 min using a matrix-matched calibration. For most compounds, the limits of detection and quantification (LOD/LOQ) are well below the maximum residue levels (MRLs) of the main regulators. The method generally demonstrates acceptable recovery values (91 compounds 75–125% and 10 compounds 30–75%). Out of 55 rice samples analyzed, 16 samples (29%) contained pesticide residues above LOQ. Four samples contained chlorpyrifos with concentrations ranging from 21.3 to 71.9 µg/kg, ten samples contained tebuconazole (34.7–69.0 µg/kg), and three samples contained pirimiphos methyl (10.7–20.7 µg/kg). The concentrations of the pesticide residues detected in these samples are well below MRL of FAO/WHO (chlorpyrifos, 500 µg/kg; tebuconazole, 1500 µg/kg; pirimiphos methyl, 7000 µg/kg). Full article

(This article belongs to the Special Issue Monitoring, Detection and Control of Food Contaminants)

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12 pages, 1766 KiB

Open AccessArticle

Optimization of Cellulase Production from Agri-Industrial Residues by Aspergillus terreus NIH2624

by Elen Ayumi Kadoguchi, Josman Velasco, Silvio Silvério da Silva, Avinash P. Ingle, Fernando Segato and Anuj Kumar Chandel

Processes 2024, 12(10), 2169; https://doi.org/10.3390/pr12102169 - 5 Oct 2024

Abstract

The objective of this study was to assess the cellulase production of four fungi: Aspergillus terreus NIH2624, Aspergillus clavatus NRRL1, Aspergillus versicolor CBS583.65 and Aspergillus phoenicis ATCC3157, under submerged cultivation conditions. When these fungi were cultured in shake flasks using Mandels and Weber’s [...] Read more.

The objective of this study was to assess the cellulase production of four fungi: Aspergillus terreus NIH2624, Aspergillus clavatus NRRL1, Aspergillus versicolor CBS583.65 and Aspergillus phoenicis ATCC3157, under submerged cultivation conditions. When these fungi were cultured in shake flasks using Mandels and Weber’s minimal medium with 1% sugarcane bagasse as a carbon source and 1.8 g/L of rice bran extract as a nitrogen source, A. terreus showed maximum cellulase production (filter paper activity (FPase) 3.35 U/mL; carboxymethyl cellulase activity (CMCase) 1.69 U/mL). Consequently, A. terreus was selected for the optimization study for cellulase production. Among the different tested carbon sources, A. terreus showed higher CMCase activity when it was cultivated on delignified sugarcane bagasse (1.64 U/mL) and higher FPase activity on sugarcane straw (7.95 U/mL). Regarding the nitrogen sources, the maximum FPase activity was observed when using rice bran (FPase, 8.90 U/mL) and soybean meal (FPase, 9.63 U/mL). The optimized fermentation medium (minimal medium with delignified sugarcane bagasse and rice bran as carbon and nitrogen sources, respectively) resulted in an enzymatic cocktail mainly composed of xylanases, with a maximum activity of 1701.85 U/mL for beechwood xylan, 77.12 U/mL for endoglucanase and 21.02 U/mL for cellobiohydrolase. Additionally, the enzymatic cocktail showed efficient activities for β-glucosidase, β-xylanase, arabinofuranosidase and lytic polysaccharide monoxygenases (LPMOs). This cellulase enzyme solution has the potential to efficiently hydrolyze lignocellulosic biomass, producing second-generation sugars in biorefineries. Full article

(This article belongs to the Special Issue Enzyme Production Using Industrial and Agricultural By-Products)

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15 pages, 1559 KiB

Open AccessArticle

Research on Magnetic Field of Permanent Magnet Rolls Arranged Periodically in Circumferential—Axial Direction

by Yuhang Zhang, Mingjiang Jiang, Youdong Jia, Xinzhi Li, Zhengfang Li and Huihua Wang

Processes 2024, 12(10), 2168; https://doi.org/10.3390/pr12102168 - 4 Oct 2024

Abstract

The separation of non-magnetic non-ferrous metals such as copper and aluminum from scrapped automobiles is a critical area of research due to the increasing number of end-of-life vehicles. Traditional eddy current separation methods have limitations, particularly in handling large-sized broken copper and aluminum [...] Read more.

The separation of non-magnetic non-ferrous metals such as copper and aluminum from scrapped automobiles is a critical area of research due to the increasing number of end-of-life vehicles. Traditional eddy current separation methods have limitations, particularly in handling large-sized broken copper and aluminum parts. This paper proposes a novel magnetic roller model featuring a circumferential–axial periodic arrangement of permanent magnets. This study explores the external magnetic field distribution of this new roller design by constructing an equivalent current model, solving magnetic scalar potential equations, and employing simulation tools. The findings indicate that the new magnet array enhances both the magnetic field strength and the range of the external magnetic field, leading to improved separation efficiency of large-sized metal fragments. The results provide a theoretical basis for advancing the separation technology of large-sized broken copper and aluminum parts in scrapped automobiles, offering potential improvements in the recycling of non-ferrous metals from end-of-life vehicles. Full article

(This article belongs to the Section Separation Processes)

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16 pages, 6896 KiB

Open AccessArticle

Numerical Simulation Study on Optimal CO₂ Injection Well Placement for Sequestration in Old Gob: A Case Study of the Huainan Mining Area

by Yongchun Chen, Yanfei Xu, Yuchen Tian, Helong Zhang, Bo Xue, Shiheng Chen, Yinghai Liu, Yanzhi Liu, Shiqi Liu, Shuxun Sang and Sijian Zheng

Processes 2024, 12(10), 2167; https://doi.org/10.3390/pr12102167 - 4 Oct 2024

Abstract

The old gob, as a potential CO₂ geological storage reservoir, has huge storage potential. To clarify the distribution characteristics and storage capacity of CO₂ in the old gob after different well deployment schemes, this study, based on the actual geological conditions [...] Read more.

The old gob, as a potential CO₂ geological storage reservoir, has huge storage potential. To clarify the distribution characteristics and storage capacity of CO₂ in the old gob after different well deployment schemes, this study, based on the actual geological conditions of the old gob in the Huainan mining area, uses the COMSOL software to numerically simulate CO₂ injection into the old gob, considering the heterogeneity of permeability and the difference in coal-rock adsorption capacity within the old gob. The research indicates that the distribution characteristics of CO₂ are significantly influenced by the deployment scheme. Specifically, different deployment schemes result in varying CO₂ concentrations and distribution patterns. Particularly, when the injection well is deployed at a depth of 65 m, the distribution of CO₂ in the low-permeability upper part of the old gob will significantly increase and the horizontal distribution range will significantly decrease. Under different well deployment modes, the CO₂ storage capacity varies significantly. When the injection well is deployed at a depth of 65 m, it is more conducive to the storage of CO₂ than at other deeper depths and the total storage capacity is larger. In addition, increasing the number of monitoring wells helps the migration and diffusion of CO₂ in the old gob. Reasonably increasing the number of monitoring wells and adopting a symmetric deployment mode can significantly improve the CO₂ storage capacity in the old gob. Through a reasonable deployment scheme, the CO₂ storage capacity in the old gob can be more than 1.8 times that of the single monitoring well deployment scheme. Overall, based on the analysis of the distribution characteristics and storage capacity, the vertical positioning of the injection wells and the deployment mode of the monitoring wells that are conducive to improving the CO₂ storage capacity in the old gob are obtained, which can provide an important reference for the well deployment scheme of CO₂ storage in the old gob. Full article

(This article belongs to the Special Issue Theoretical Progress in the Exploration and Development of Deep Coal-Measure Gas)

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