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Volume 14
Issue 5
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Processes, Volume 14, Issue 5 (March-1 2026) – 151 articles

Cover Story (view full-size image): Copper is especially challenging in the current transition from blast to electric arc furnaces, as it remains in the melt, reducing the mechanical properties of the produced crude steel while being lost to any secondary use. This work proposes an additional approach to manual sorting and XRF by using computer vision and machine learning methods to detect and eject copper-containing particles in a post-shredder scrap fraction on low-cost hardware. Furthermore, this proposed method is robust to environmental factors, such as heavily corroded particles caused by prolonged storage without proper weather protection. This method may reduce the need for expensive XRF equipment or manual sorting. The developed sorting pipeline was examined in an industrial setting through sorting trials and achieved high purity in the produced iron fraction. View this paper
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16 pages, 818 KB  
Article
Study on Scaling Mechanism and Prevention Technology of Shale Gas Wellbore
by Qiaoping Liu, Lingxin Wang, Jianyi Liu and Liangyuan He
Processes 2026, 14(5), 879; https://doi.org/10.3390/pr14050879 - 9 Mar 2026
Viewed by 348
Abstract
In recent years, screen pipe scaling and blockage have occurred in dozens of wells in the Fuling Shale Gas Field, seriously affecting the normal production of gas wells. Investigations show that similar problems exist in the Weirong Shale Gas Field of Sinopec Southwest [...] Read more.
In recent years, screen pipe scaling and blockage have occurred in dozens of wells in the Fuling Shale Gas Field, seriously affecting the normal production of gas wells. Investigations show that similar problems exist in the Weirong Shale Gas Field of Sinopec Southwest Branch, and the Changning and Weiyuan Shale Gas Fields of PetroChina. Although well production has been restored through pipe inspection operations, key issues specific to shale gas wells remain unresolved, including the scaling mechanism under gas–liquid two-phase flow regimes unique to horizontal shale gas wells, the scale deposition law at screen pipes caused by complex flow direction changes, and the targeted prevention technologies for high-hardness BaSO4 scale in high-salinity produced water. By jointly conducting research on the scaling mechanism and prevention technology of shale gas wellbores with Southwest Petroleum University, the Fuling Shale Gas Field has identified the reasons why the amount of BaSO4 scaling increases with the decrease in pressure and temperature, while it increases with the increase in gas–water ratio. It has clarified the influencing characteristics of factors such as pressure, temperature, gas–water ratio and pipe wall roughness. The amount of scaling on the tubing wall of shale gas wells in this area is very small, and blockage mainly occurs at and near the screen pipe. Due to the complex flow direction change in gas and water in the screen pipe, the precipitated tiny scale particles separate, settle and accumulate, forming variable-diameter steps that continue to grow. Two agents have been developed: the LPPAS scale inhibitor and the barium-strontium-sulfate-chelating plug-removing agent, with a scale inhibition rate as high as over 90% and a scale dissolution rate over 70%, respectively, laying a foundation for the efficient and stable production of shale gas wells. Full article
(This article belongs to the Section Petroleum and Low-Carbon Energy Process Engineering)
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25 pages, 7590 KB  
Article
Rock Brittleness Prediction with BDEGTO-Optimized XGBoost
by Yajuan Wu, Tao Wen, Ruozhao Wang, Yunpeng Yang and Xiaohong Xu
Processes 2026, 14(5), 878; https://doi.org/10.3390/pr14050878 - 9 Mar 2026
Viewed by 241
Abstract
Precise assessment of rock brittleness is a prerequisite for effective wellbore integrity and successful reservoir stimulation in drilling programs. To achieve precise prediction of rock brittleness index (BI), this study proposes an improved optimization algorithm for an artificial gorilla troops optimizer (GTO), called [...] Read more.
Precise assessment of rock brittleness is a prerequisite for effective wellbore integrity and successful reservoir stimulation in drilling programs. To achieve precise prediction of rock brittleness index (BI), this study proposes an improved optimization algorithm for an artificial gorilla troops optimizer (GTO), called a Bernoulli Differential Evolution Gorilla Troops Optimizer (BDEGTO). In the BDEGTO, Bernoulli mapping is introduced during the population initialization process, and the differential evolution is embedded after the exploration stage of the GTO. These modifications effectively address the early-stage optimization weaknesses and the susceptibility to local optima that are commonly encountered in a traditional GTO. To evaluate the performance of the BDEGTO, comparisons are made with other optimization algorithms based on 91 datasets from 32 rock types. The results demonstrate the significant advantages of the BDEGTO over other algorithms. Furthermore, the BDEGTO is applied to the optimization process of Least Squares Boosting (LSB), Extreme Gradient Boosting (XGB), and Light Gradient Boosting Machine (LGBM). A comparison is made with Support Vector Regression (SVR), Artificial Neural Network (ANN), and Convolutional Neural Network (CNN) algorithms for predicting rock brittleness based on input parameters such as P-wave velocity (Vp), point load index (Is50), and unit weight (UW). The findings indicate that BDEGTO-XGB achieves the best prediction performance for BI. Additionally, through SHapley Additive exPlanations (SHAP) analysis, it is determined that among the three input parameters, Is50 has the most significant influence. These research results provide valuable guidance for the brittleness assessment of similar rocks. Full article
(This article belongs to the Section Petroleum and Low-Carbon Energy Process Engineering)
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13 pages, 1504 KB  
Article
Process Differences in Phosphorus Release Between Wetland and River Sediments in a Plain River Network
by Yinan Liu, Xin Xu, Jianglong Cui, Dongya Tang and Shanshan Zhao
Processes 2026, 14(5), 877; https://doi.org/10.3390/pr14050877 - 9 Mar 2026
Viewed by 322
Abstract
The release process of endogenous phosphorus (P) in the sediments of large ecological wetlands and their connected rivers in the plain river network area shows temporal and spatial differences. This study investigated P dynamics of the sediments in a large ecological wetland and [...] Read more.
The release process of endogenous phosphorus (P) in the sediments of large ecological wetlands and their connected rivers in the plain river network area shows temporal and spatial differences. This study investigated P dynamics of the sediments in a large ecological wetland and its connected rivers in a plain river network area. Sample collection occurred across three periods (October 2024, March 2025, and July 2025). P source-sink characteristics and microbial regulatory mechanisms were analyzed to clarify differences in the P release processes between wetland (SS) and river (SH) sediments. The results showed that the total phosphorus (TP) concentration in overlying water was highest in July (0.16 mg/L), while the TP content in SS was relatively low, with a mean value of 514.1 mg/kg. SS generally acted as a P sink, with its zero equilibrium P concentrations (EPC0) significantly lower than those of river sediments (SH), reaching a minimum of 0.01 mg/L, and its maximum P sorption capacity (Qmax) higher, with a maximum value of 1.413 mg/g. In contrast, SH mainly served as a P source, with a particularly high release risk in spring and summer. Seasonal changes significantly influenced P behavior, and sorption capacity was highest in spring (March), while the high EPC0 of SH still facilitated P release under actual water conditions. In autumn, elevated microbial diversity enhanced organic matter mineralization to increase EPC0 and P release risk (p < 0.05), while in summer, specific functional phyla (Proteobacteria and Bacteroidota) simultaneously regulated both adsorption capacity (Qmax) and release threshold (EPC0) through organic matter mineralization, iron reduction, and competitive sorption (p < 0.05). This study provides scientific support for internal pollution control in ecological wetlands and watershed phosphorus management in plain river network areas. Full article
(This article belongs to the Section Environmental and Green Processes)
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21 pages, 1139 KB  
Article
Comparative Assessment of Energy and Emission Costs for Geothermal Heat Pumps and Fossil-Fuel Heating Systems Across U.S. Climatic Zones
by Md Shahin Alam, Shima Afshar, Seyed Ali Arefifar and Mohammad Haq
Processes 2026, 14(5), 876; https://doi.org/10.3390/pr14050876 - 9 Mar 2026
Viewed by 491
Abstract
In response to growing concerns over global warming and energy sustainability, transitioning from fossil-fuel-based heating systems to renewable alternatives is essential. This study evaluates the economic and environmental performance of geothermal heat pumps for building heating and compares it with conventional coal-fired boilers, [...] Read more.
In response to growing concerns over global warming and energy sustainability, transitioning from fossil-fuel-based heating systems to renewable alternatives is essential. This study evaluates the economic and environmental performance of geothermal heat pumps for building heating and compares it with conventional coal-fired boilers, natural-gas boilers, and diesel furnaces. Using the heating degree-day (HDD) method, heating energy demand was analyzed for four U.S. cities—Anchorage (AK), San Francisco (CA), Salt Lake City (UT), and Las Vegas (NV)—representing diverse climatic zones. The analysis integrates thermodynamic and economic parameters, including the coefficient of performance (COP = 2–5) and annual fuel-utilization efficiency (AFUE = 80–97%), to evaluate heating-system performance and operational cost across different climatic regions. Sensitivity analysis with ±10% variations in fuel and electricity prices and system efficiencies demonstrates that geothermal heating remains the most stable and emission-efficient option under all scenarios. Results indicate that geothermal systems, despite higher reported initial investment, achieve lower operational and emissions-related costs and offer a robust and sustainable solution for decarbonizing building-heating systems. For example, the estimated seasonal geothermal heating cost is $370.59 in Anchorage compared with $646.48 for coal heating and $3375.65 for diesel systems. Furthermore, policy evaluation indicates that federal and state incentives, such as investment tax credit under the Inflation Reduction Act and rebate programs, can reduce installation costs by 25–40%, improving economic feasibility, particularly in colder regions. The analysis focuses exclusively on energy and emissions-related costs and does not explicitly model capital investment or levelized cost metrics. Full article
(This article belongs to the Special Issue Optimization and Analysis of Energy System)
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22 pages, 1468 KB  
Article
Predicting Human Thermal Comfort During Winter Heating Using Multi-Class Machine Learning Algorithms
by Tongwen Wang, Weijie Huang, Haiyan Yan, Jingyuan Gao, Yawei Li and Yongxuan Guo
Processes 2026, 14(5), 875; https://doi.org/10.3390/pr14050875 - 9 Mar 2026
Viewed by 367
Abstract
To address the critical need for accurate human thermal comfort prediction in winter heating environments, this study established a comprehensive thermal comfort dataset containing 2089 valid samples through experiments. On this basis, thermal comfort prediction models were constructed using three multi-class machine learning [...] Read more.
To address the critical need for accurate human thermal comfort prediction in winter heating environments, this study established a comprehensive thermal comfort dataset containing 2089 valid samples through experiments. On this basis, thermal comfort prediction models were constructed using three multi-class machine learning algorithms: Support Vector Classification, K-Nearest Neighbors, and Random Forest. The predictive performance of 63 different feature combinations was systematically evaluated. The results indicate that the feature subset comprising indoor air temperature, forehead temperature, cheek temperature, dorsal hand temperature, heart rate, and systolic blood pressure yields the optimal prediction performance. Among the evaluated models, the Random Forest model demonstrated superior overall performance, achieving an accuracy exceeding 90% and an AUC ranging from 96% to 99%, significantly outperforming the SVC and KNN models. Compared with the traditional Predicted Mean Vote (PMV) model, the machine learning models developed in this study showed a substantial improvement in prediction accuracy under identical conditions; notably, the Random Forest model improved accuracy by approximately 40% over the PMV model. Based on these findings, a smart heating system framework integrating environmental sensors, wearable devices, and intelligent control valves is proposed, providing a theoretical basis and technical approach for realizing personalized and energy-efficient heating control. Full article
(This article belongs to the Section Automation Control Systems)
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12 pages, 248 KB  
Article
Nutritional Composition, Phenolic Compounds, and Antioxidant Capacity of Blue Corn Tortillas Fortified with Quelites (Amaranthus hybridus L.)
by Alma Haydee Astorga-Gaxiola, Manuel Adrian Picos-Salas, Luis Angel Cabanillas-Bojórquez, Nayely Leyva-López, Erick Paul Gutiérrez-Grijalva, Melissa García-Carrasco, J. Basilio Heredia and Jesús Estrada-Manjarrez
Processes 2026, 14(5), 874; https://doi.org/10.3390/pr14050874 - 9 Mar 2026
Viewed by 374
Abstract
Tortillas are an essential food staple in the Mexican diet due to their nutritional value. Blue corn tortillas have been reported as a source of bioactive compounds, such as phenolic compounds and flavonoids. Likewise, the blue corn tortillas have been studied to enhance [...] Read more.
Tortillas are an essential food staple in the Mexican diet due to their nutritional value. Blue corn tortillas have been reported as a source of bioactive compounds, such as phenolic compounds and flavonoids. Likewise, the blue corn tortillas have been studied to enhance the nutritional and nutraceutical composition. In this sense, Quelites are a large family of plants with macronutrient and micronutrient content, as well as a source of phenolic compounds, flavonoids, and carotenoids. Among these, Amaranthus hybridus L. could fortify the blue corn tortilla composition. Therefore, this study aims to fortify blue corn tortillas with different concentrations of Quelites flours. The total flavonoid and phenolic compounds content, as well as the antioxidant capacity and identification of phenolic compounds, were evaluated on tortillas fortified with Quelites. The addition of Quelites to blue corn tortillas reduced the lipid and protein content, carbohydrate, and flavonoid content, and enhance the antioxidant capacity of tortillas as measured by FRAP, ORAC, and TEAC assays. Also, caffeic acid, chlorogenic acid, ferulic acid, and sinapic acid were identified on blue corn tortillas fortified with Quelites. These results support the use of A. hybridus L. as an ingredient to improve the nutrient and nutraceutical composition of foods. Full article
(This article belongs to the Special Issue Extraction, Analysis and Process Optimization of Bioactive Compounds from Food Sources)
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22 pages, 6941 KB  
Article
Study on the Impact of Viscoelastic Surfactants on the Reaction-Retarding Performance of Carbonate Reservoir Acidizing
by Wenhao Tian, Juan Du, Yaochen Li and Jinlong Li
Processes 2026, 14(5), 873; https://doi.org/10.3390/pr14050873 - 9 Mar 2026
Viewed by 337
Abstract
Conventional hydrochloric acid (HCl) acidizing in carbonate reservoirs is often limited by excessively rapid acid–rock reactions and preferential flow through high-permeability paths, resulting in shallow penetration and inefficient stimulation. Viscoelastic surfactant (VES)-based diverting acids have been widely applied to address these challenges; however, [...] Read more.
Conventional hydrochloric acid (HCl) acidizing in carbonate reservoirs is often limited by excessively rapid acid–rock reactions and preferential flow through high-permeability paths, resulting in shallow penetration and inefficient stimulation. Viscoelastic surfactant (VES)-based diverting acids have been widely applied to address these challenges; however, the intrinsic relationship between reaction retardation and diversion efficiency, particularly under varying shear conditions, remains insufficiently clarified. In this study, a VES-based diverting acid system formulated with erucamidopropyl hydroxysultaine (EH50) was systematically investigated through multiscale experiments, including rotating disk reaction kinetics, rheological characterization, porous core flooding, and fracture-scale plate flow tests. The results reveal a pronounced shear-dependent transition in the governing mechanism of the system. Under low-shear conditions, the VES system significantly reduces the apparent acid–rock reaction rate, with a maximum reduction of 77.3%, and exhibits a synergistic retardation effect in the presence of Ca2+, indicating mass transfer limitation. However, under high-shear porous media flow, the intrinsic retarding effect is substantially weakened due to partial disruption of the viscoelastic structure. Despite this attenuation of chemical retardation, effective diversion performance persists under dynamic flow conditions, manifested by pressure plateau behavior, enhanced flow redistribution, more distributed wormhole networks, and greater overall dissolution. Fracture-scale experiments further demonstrate that the diversion acid suppresses excessive inlet etching and promotes spatially distributed etching patterns favorable for fracture conductivity maintenance. These findings clarify that reaction retardation and diversion are distinct yet dynamically coupled mechanisms, whose relative dominance depends on shear intensity and ionic environment. The proposed shear-responsive mechanism framework provides new insight into the design and optimization of VES diverting acid systems for carbonate reservoir stimulation. Full article
(This article belongs to the Topic Advanced Technology for Oil and Nature Gas Exploration)
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15 pages, 3567 KB  
Article
Intelligent Prediction Method for Pipeline Structural Health State Under Fault Movement
by Ning Shi, Tianwei Kong, Kaifang Hou, Wancheng Ding, Jie Jia and Hong Zhang
Processes 2026, 14(5), 872; https://doi.org/10.3390/pr14050872 - 9 Mar 2026
Viewed by 283
Abstract
The rapid development of the oil and gas industry has led to increasingly severe challenges for buried pipelines when crossing complex geological environments. Especially in fault zones induced by seismic action, the pipe–soil interaction mechanism and the rapid judgment of pipeline mechanical response [...] Read more.
The rapid development of the oil and gas industry has led to increasingly severe challenges for buried pipelines when crossing complex geological environments. Especially in fault zones induced by seismic action, the pipe–soil interaction mechanism and the rapid judgment of pipeline mechanical response urgently require in-depth research. This study conducted pipe–soil interaction tests on pipeline uplift under seismic-frequency loading, and for the first time, proposed a modified soil-spring method suitable for typical soft clay under seismic wave frequencies of 1–5 Hz. Through numerical simulation, the axial strain response of pipelines under normal fault movement was systematically analyzed. Considering comprehensively various variables such as fault dip angle, seismic wave frequency, internal pipeline pressure and wall thickness variation, this study extracted the maximum and minimum strain characteristics of the pipe top and pipe bottom, established a diversified intelligent prediction system for fault geological hazards, constructed the optimal machine learning model matching the type of normal fault geological hazards, and realized full-process intelligent modeling from model selection to parameter optimization. The research results can provide technical support for the seismic design and safety status prediction of pipelines under normal faulting conditions. Full article
(This article belongs to the Special Issue Investigation of the Gas–Liquid Flow and Separation Behaviors in Pipelines)
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14 pages, 1886 KB  
Article
Adaptive Discrete Control of a Rotary Dryer with Time Delay in Potash Fertilizer Production
by Akmalbek Abdusalomov, Suban Khusanov, Islomnur Ibragimov, Jasur Sevinov, Mukhriddin Mukhiddinov and Young Im Cho
Processes 2026, 14(5), 871; https://doi.org/10.3390/pr14050871 - 9 Mar 2026
Viewed by 345
Abstract
This paper presents the design and industrial implementation of an adaptive discrete control system for a rotary dryer operating in potash fertilizer production. The drying process is characterized by high inertia, multivariable interactions, transport delay, and non-stationary behavior resulting from variations in raw [...] Read more.
This paper presents the design and industrial implementation of an adaptive discrete control system for a rotary dryer operating in potash fertilizer production. The drying process is characterized by high inertia, multivariable interactions, transport delay, and non-stationary behavior resulting from variations in raw material properties and external disturbances, which significantly reduce the effectiveness of conventional fixed-parameter controllers. A discrete-time mathematical model of the rotary drying process was developed using industrial experimental data collected from a full-scale production plant. The process was modeled as a coupled 2 × 2 multivariable system with pronounced time-delay effects in the main control channels. System identification was carried out using statistical and frequency-domain methods to capture the dominant dynamic characteristics required for controller synthesis. Based on the identified model, an adaptive discrete controller with online parameter adjustment was developed to regulate outlet moisture content and exhaust gas temperature. Simulation and industrial results confirmed stable operation under varying conditions, improved regulation accuracy, enhanced process stability, and an average production efficiency increase of approximately 1.8%, accompanied by reduced fuel consumption. Full article
(This article belongs to the Section Automation Control Systems)
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17 pages, 5016 KB  
Article
Bioprocess Scale-Up: A Computational Fluid Dynamics Approach for the Bioproduction of Succinic Acid from Glycerol
by Ioannis Zacharopoulos and Constantinos Theodoropoulos
Processes 2026, 14(5), 870; https://doi.org/10.3390/pr14050870 - 9 Mar 2026
Viewed by 476
Abstract
In this work, we present the scale-up of a batch anaerobic fermentation system for the production of succinic acid from glycerol using A. succinogenes. The system has been successfully scaled up from an initial bioreactor working volume of 1 L (laboratory scale) [...] Read more.
In this work, we present the scale-up of a batch anaerobic fermentation system for the production of succinic acid from glycerol using A. succinogenes. The system has been successfully scaled up from an initial bioreactor working volume of 1 L (laboratory scale) to a working volume of 100 L (pilot scale). At the same time, we have developed a hybrid model, combining the intrinsic kinetics of the microbial growth, with a computational fluid dynamics model (CFD) of the bioreactor. The proposed model is able to predict the productivity drop, usually observed while scaling up a bioprocess. In our process, this is a result of the limitations on the mass transfer of CO2 between the gas and the liquid phase of the system. The model is successfully used to predict the amount of aeration needed in order to achieve increased succinic acid productivity. Using the model, the final succinic acid increased by 4.3%, and the succinic acid productivity increased by 8.5%, while the fermentation by-products decreased by approxiamtely 3% each. Full article
(This article belongs to the Special Issue Innovative Bioreactor Design and Advanced Optimization Strategies for Biorefineries and Bioprocessing)
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18 pages, 10495 KB  
Article
Study on the Impact of Photovoltaics on Surface Wind and Evaporation over Water Surfaces
by Yufan Huang, Xiaoli Chen, Li Zeng and Yafei Duan
Processes 2026, 14(5), 869; https://doi.org/10.3390/pr14050869 - 8 Mar 2026
Viewed by 319
Abstract
Photovoltaic (PV) is the most promising clean energy, and water-surface PVs have been developing rapidly due to less land occupation. For south-facing fixed PV arrays, differences in the wind direction–angle will lead to variations in wind resistance. In this paper, surface wind speed [...] Read more.
Photovoltaic (PV) is the most promising clean energy, and water-surface PVs have been developing rapidly due to less land occupation. For south-facing fixed PV arrays, differences in the wind direction–angle will lead to variations in wind resistance. In this paper, surface wind speed and evaporation near the water surface of a PV-covered fish pond are observed. Results show the ratio of wind speed in the PV area to the reference site (denoted as α) is 0.2~0.3 in the south-biased wind direction, and 0.5~0.6 in the north-biased and east wind direction. A statistical formula for α with wind direction is proposed. The α values agree with previous conclusions from studies of single wind directions. Then the monthly average wind speed reduction ratio is calculated using the environmental wind rose diagram and α. The measured ratio of the monthly evaporation amount from the PV site to the reference site agrees well with that of the monthly wind speed. The method is applied to evaluate evaporation reduction at three PV sites of different latitudes. The results show the evaporation reduction by PVs is more than 50% at all three sites, and the maximum annual amount of 1236 mm occurred with a prevailing wind direction S. Full article
(This article belongs to the Special Issue Advances in Hydrodynamics, Pollution and Bioavailable Transfers)
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20 pages, 5824 KB  
Article
Research on Enhanced Gas Recovery by CO2/N2 Injection in Tight Sandstone Gas Reservoirs
by Lili Liu, Jinbu Li, Pengcheng Liu, Bin Fu, Yufei Wang, Junjie Zhong, Zhixing Wu, Cheng Cao, Yulong Zhao, Haonan Zhu and Junpu Hou
Processes 2026, 14(5), 868; https://doi.org/10.3390/pr14050868 - 8 Mar 2026
Viewed by 396
Abstract
CO2-enhanced gas recovery (CO2-EGR) is a crucial technology for achieving both natural gas production increase and CO2 geological storage. While pure CO2 flooding demonstrates favorable recovery performance, the technical challenges and high costs associated with purifying CO [...] Read more.
CO2-enhanced gas recovery (CO2-EGR) is a crucial technology for achieving both natural gas production increase and CO2 geological storage. While pure CO2 flooding demonstrates favorable recovery performance, the technical challenges and high costs associated with purifying CO2 remain significant. CO2 purification from exhaust gas incurs prohibitive costs, while direct injection of an unpurified CO2–N2 mixture can greatly cut engineering expenditure. Nitrogen also provides synergistic pressure support, working with CO2 to drive natural gas displacement. Therefore, from an economic and practical standpoint, employing impure CO2 mixtures (e.g., CO2–N2) for flooding presents a more advantageous approach. To clarify the factors influencing the recovery enhancement in tight sandstone gas reservoirs using CO2–N2 mixtures, long-core flooding experiments were conducted at 100 °C. This study systematically investigates the impact patterns of three key factors—injection timing, injection rate, and injection gas composition—on the enhanced recovery of tight sandstone gas reservoirs. The experimental results indicate that: (1) Advancing the injection timing significantly improves the recovery performance for both CO2 and N2 flooding. However, the cumulative recovery factor (sum of the depletion recovery and the incremental recovery from gas injection) shows a declining trend. (2) The enhanced recovery effect exhibits a trend of first increasing and then decreasing with the increase in injection rate. When the injection rate exceeds 0.05 mL/min, it tends to cause premature breakthrough of the injected gas, thereby reducing the displacement efficiency. (3) As the proportion of CO2 in the injected gas increases, the enhanced recovery effect shows a nonlinear rise. The highest incremental recovery (17.02%) was achieved with pure CO2 flooding, while pure N2 flooding yielded the lowest result (14.64%). The research findings, from a macroscopic perspective, elucidate the influence patterns of three distinct factors on enhancing gas recovery in tight sandstone reservoirs, thereby providing theoretical foundation and scientific guidance for the development of such reservoirs. In summary, the injection timing, injection rate and CO2 proportion in injected gas are the key controlling factors for gas flooding enhanced recovery in tight sandstone reservoirs. This study clarifies the macroscopic influence law of each factor, and the optimized development parameters proposed can provide direct theoretical support and technical guidance for the on-site application of gas flooding in tight sandstone reservoirs. Full article
(This article belongs to the Topic Petroleum and Gas Engineering, 2nd edition)
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26 pages, 3351 KB  
Article
Retrofit Design of a De-Isobutanizer Column via Vapor Recompression: Techno-Economic and CO2 Emission Analysis
by Maria Santos Coelho, Sophia Sardinha de Oliveira, Rafaella Machado de Assis Cabral Ribeiro, Fernanda Ribeiro Figueiredo and Diego Martinez Prata
Processes 2026, 14(5), 867; https://doi.org/10.3390/pr14050867 - 8 Mar 2026
Viewed by 383
Abstract
Isobutane is a key feedstock for alkylate production. For separating an equimolar isobutane/n-butane mixture with 2 mol% ethane, two conventional designs are reported in the literature: a single water-cooled condenser (SC) and a dual condenser system with refrigeration (DC). This study proposes two [...] Read more.
Isobutane is a key feedstock for alkylate production. For separating an equimolar isobutane/n-butane mixture with 2 mol% ethane, two conventional designs are reported in the literature: a single water-cooled condenser (SC) and a dual condenser system with refrigeration (DC). This study proposes two vapor recompression retrofit configurations, SC-VR and SC-PHVR (with preheating), to improve energy efficiency and enable electrification. Economic and environmental performance were evaluated using total annualized cost (TAC) and CO2 emissions. Compared with SC and DC schemes, SC-VR reduces CO2 emissions by 49 and 52%, while SC-PHVR delivers higher reductions of 64 and 66%. A sensitivity analysis of electricity prices across 3-, 5-, and 10-year payback periods indicates the most favorable performance at 10 years. At 16.67 USD/GJ, SC-PHVR lowers TAC by 22 and 25%; in contrast, SC-VR provides marginal savings. At 24.03 USD/GJ, SC-VR is not economically competitive, whereas SC-PHVR continues to outperform the conventional cases, with TAC reductions of 8% and 4%. Both retrofit options significantly reduce emissions, with SC-PHVR offering the best economic performance. Finally, the proposed configurations enable the complete electrification of the de-isobutanizer system, eliminating reliance on fossil-based thermal utilities, which allows the use of renewable sources in line with the decarbonization efforts. Full article
(This article belongs to the Special Issue Circular Economy in Process Engineering: Impact Assessment and Directions for Sustainability)
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23 pages, 16317 KB  
Article
Evolution and Prediction of Deep Coal–Rock Fracture Conductivity with Energy-Based Breakage Criterion of Proppant
by Pengyin Yan and Zhiming Wang
Processes 2026, 14(5), 866; https://doi.org/10.3390/pr14050866 - 8 Mar 2026
Viewed by 362
Abstract
It is of great significance to clarify the evolution law and control mechanism of fracture conductivity in different production stages for the efficient development of coalbed methane. However, research on fracture conductivity in coal–rock remains limited, and the existing models are inadequate for [...] Read more.
It is of great significance to clarify the evolution law and control mechanism of fracture conductivity in different production stages for the efficient development of coalbed methane. However, research on fracture conductivity in coal–rock remains limited, and the existing models are inadequate for predicting fracture conductivity with a consideration of staged proppant crushing. To address this gap, long-term conductivity tests were conducted on deep coal–rock under varying closure pressures and proppant gradation ratios. Within a coupled computational fluid dynamics and discrete element method (CFD-DEM) framework, a particle substitution scheme was integrated with the energy-based breakage model (Tavares breakage model) to develop a fracture conductivity predictor that incorporates proppant crushing and captures the time-dependent kinetics of proppant breakage during fracture conductivity evaluation. The model’s predictions align well with the experimental data, with an average error of less than 5%. The results indicate that fracture conductivity evolution can be delineated into three stages according to particle-breakage characteristics, (i) proppant pack compaction, (ii) the primary crushing of coarse proppant grains, and (iii) the secondary crushing of proppant fines, and the contributions of these three stages to the total conductivity loss are approximately 60%, 30%, and 10%, respectively. At a low closure pressure, fracture conductivity varies markedly among proppant packs with different particle sizes; once the closure pressure exceeds 40 MPa, the proppant pack enters the fines-breakage stage, and the conductivity differences among various particle size blends become marginal. Furthermore, a semi-empirical prediction model incorporating a composite crushing factor (CCF) was developed based on the Kozeny–Carman relationship, enabling a rapid evaluation of fracture conductivity in deep coal–rock fractures. Overall, these results provide a practical basis for fracture conductivity prediction and hydraulic fracturing parameter optimization in coal–rock reservoirs. Full article
(This article belongs to the Special Issue Advanced Fracturing Technology for Oil and Gas Reservoir Stimulation (2nd Edition))
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34 pages, 4078 KB  
Review
Breaking the “Forever Chemical” Cycle: A Critical Review of Per- and Polyfluoroalkyl Substances in Solid Waste Sources and Their Fate During Thermal Treatment
by Jiyuan Chen, Jingyong Liu, Fatih Evrendilek, Leyao Tao, Chenxin Yao, Zhanghua Zou, Tao Chen, Liangzhong Li, Bin Cai, Guanzheng Zhuang, Gulsun Akdemir Evrendilek and Jianli Huang
Processes 2026, 14(5), 865; https://doi.org/10.3390/pr14050865 - 8 Mar 2026
Viewed by 571
Abstract
The persistence of per- and polyfluoroalkyl substances (PFASs) poses a significant challenge in solid waste management. This paper systematically reviews the distribution characteristics of PFASs in various solid waste streams, including industrial sludge, food packaging, textiles, and electronic waste. It also evaluates the [...] Read more.
The persistence of per- and polyfluoroalkyl substances (PFASs) poses a significant challenge in solid waste management. This paper systematically reviews the distribution characteristics of PFASs in various solid waste streams, including industrial sludge, food packaging, textiles, and electronic waste. It also evaluates the removal efficiency of four thermal treatment technologies—incineration, pyrolysis, smoldering combustion, and hydrothermal liquefaction (HTL)—for PFASs in solid waste. Although incineration and smoldering combustion can achieve destruction and removal efficiencies exceeding 99.99%, the release of short-chain byproducts remains a critical bottleneck. Pyrolysis effectively decontaminates solid-phase products but carries the risk of phase transfer into pyrolysis oils. The efficiency of HTL is highly dependent on process parameters. PFAS degradation is a radical-mediated process initiated by the dissociation of functional groups. We emphasize that substrate surface properties and the presence of counterions play pivotal roles in modulating these reaction pathways. The introduction of water vapor (as a hydrogen-rich medium), alkaline additives, or specific catalysts is considered a promising strategy to inhibit the recombination of reactive byproducts and enhance mineralization rates. Full article
(This article belongs to the Special Issue Chemical and Microbiological Analyses of Wastes, Effluents and Materials)
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21 pages, 4977 KB  
Article
Evolution of High-Voltage Frequency-Domain Dielectric Spectroscopy Characteristics of Oil-Pressboard Insulating Bushings Under Aging and Moisture
by Huan Li, Mingcheng Hua, Yueyang Ma, Chunjia Gao, Zheng Niu, Deliang Cheng, Guangwei Liu and Bo Qi
Processes 2026, 14(5), 864; https://doi.org/10.3390/pr14050864 - 8 Mar 2026
Viewed by 347
Abstract
The insulation condition of oil-pressboard insulating bushings is commonly evaluated by measuring the dielectric loss factor and capacitance at power frequency. However, systematic investigations into the influence of aging and moisture defects on frequency-domain dielectric spectroscopy (FDS) characteristics are still insufficient. To address [...] Read more.
The insulation condition of oil-pressboard insulating bushings is commonly evaluated by measuring the dielectric loss factor and capacitance at power frequency. However, systematic investigations into the influence of aging and moisture defects on frequency-domain dielectric spectroscopy (FDS) characteristics are still insufficient. To address this issue, a 10 kV high-voltage FDS measurement system was independently developed. The system has an output voltage range of 0~10 kV and a test frequency band of 1 mHz~10 Hz, with excellent measurement stability and high test accuracy. The standard deviation of dielectric loss of the system is on the order of 10−4 and the relative error is less than 5%. It also features reliable weak current detection capability and thermal stability. Based on this system, the dielectric spectral characteristics of oil-pressboard insulation models with different moisture contents and aging levels were investigated under various temperatures and applied voltages. The results indicate that the dielectric spectrum shifts toward higher frequencies with increasing temperature. Moreover, the low-frequency dielectric loss of degraded insulation increases linearly with the applied voltage, and the rate of increase shows a positive correlation with both moisture content and aging duration. As insulation degradation becomes more severe, the voltage-dependent characteristic frequency moves toward higher frequencies. This frequency refers to the characteristic frequency where the dielectric loss of insulation presents an obvious linear variation with the change of applied voltage. Unaged and dry bushings exhibit only weak voltage dependence at 0.01 Hz, whereas bushings aged for 28 days with a moisture content of 4.121% demonstrate pronounced voltage dependence at 10 Hz. These results provide a valuable technical basis for diagnosing coupled aging and moisture defects in oil-pressboard insulated bushings. Full article
(This article belongs to the Section Petroleum and Low-Carbon Energy Process Engineering)
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32 pages, 25734 KB  
Article
Composite Finite-Time ADRC for Flexible-Joint Manipulators with Frequency-Domain Separation
by Zhongbo Shao and Ming Wu
Processes 2026, 14(5), 863; https://doi.org/10.3390/pr14050863 - 8 Mar 2026
Viewed by 287
Abstract
Flexible-joint manipulators suffer from severe performance degradation due to the coupling of joint elasticity and varying loads. To address this, we propose a composite finite-time active disturbance rejection control (CFT-ADRC) strategy utilizing a frequency-domain separation architecture. A recursive least squares (RLS) algorithm identifies [...] Read more.
Flexible-joint manipulators suffer from severe performance degradation due to the coupling of joint elasticity and varying loads. To address this, we propose a composite finite-time active disturbance rejection control (CFT-ADRC) strategy utilizing a frequency-domain separation architecture. A recursive least squares (RLS) algorithm identifies slow-varying load parameters, while an extended state observer (ESO) compensates for high-frequency unmodeled dynamics and external disturbances, effectively preventing loop interference. A finite-time control law guarantees rapid tracking error convergence. Comprehensive simulations confirm that this approach significantly outperforms standard ADRC and neural network-based methods (RBFNN-ASMC). Under 50% load variations, it achieves an RMS tracking error of 2×10−3 rad and maintains robust stability during 200% instantaneous load mutations. The strategy presents a strong theoretical framework for future hardware implementation while maintaining an optimal balance of precision, robustness, and computational simplicity. Full article
(This article belongs to the Section Automation Control Systems)
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19 pages, 992 KB  
Article
Catalytic Reforming Strategies for Tar Reduction and Hydrogen Enhancement in Biomass Gasification
by Ersin Üresin
Processes 2026, 14(5), 862; https://doi.org/10.3390/pr14050862 - 8 Mar 2026
Viewed by 442
Abstract
Catalytic biomass gasification is considered a promising route for the production of hydrogen-rich syngas. However, the impact of catalytic enhancement on gas composition is a complex phenomenon, as experimental outcomes are often strongly dependent on reactor configurations and kinetic effects. To address these [...] Read more.
Catalytic biomass gasification is considered a promising route for the production of hydrogen-rich syngas. However, the impact of catalytic enhancement on gas composition is a complex phenomenon, as experimental outcomes are often strongly dependent on reactor configurations and kinetic effects. To address these challenges, a thermodynamic equilibrium-based modeling approach was developed to theoretically investigate the influence of catalytic enhancement in biomass steam gasification. The gasification process was modeled using Gibbs free energy minimization, focusing on the elemental composition of biomass and the equilibrium distribution among the major gaseous species, namely H2, CO, CO2, CH4, and H2O. The effects of the different catalyst types, including dolomite, Ni/olivine, and iron-based catalysts, were examined through catalyst-dependent activity coefficients. Simulations were carried out under steam gasification conditions at atmospheric pressure, with particular emphasis on the influence of temperature, steam-to-biomass ratio, and catalyst activity on syngas composition. The results showed that increasing catalyst activity enhanced hydrogen production while suppressing methane formation, primarily through intensified tar reforming and water–gas shift reactions. The model successfully reproduced widely accepted thermodynamic trends reported in the literature. Overall, the proposed framework can provide a flexible and computationally efficient screening-level tool for the theoretical assessment of catalytic effects in biomass gasification, offering valuable insights for preliminary catalyst selection and conceptual process design. Full article
(This article belongs to the Special Issue Catalytic Improvement of Biomass Gasification Process)
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33 pages, 12512 KB  
Article
Numerical Simulation of Air–Steam Mixture Condensation in a Falling Film Condenser
by Hanyu Zhong and Jiafeng Wu
Processes 2026, 14(5), 861; https://doi.org/10.3390/pr14050861 - 8 Mar 2026
Viewed by 294
Abstract
Shell-and-tube falling film condensers are critical in fields like energy, petrochemicals, and waste heat recovery. Their operation predominantly involves the complex mixed condensation of steam and non-condensable gases. This process couples multi-physical phenomena—gas flow, liquid film dynamics, phase change, and non-condensable gas accumulation—making [...] Read more.
Shell-and-tube falling film condensers are critical in fields like energy, petrochemicals, and waste heat recovery. Their operation predominantly involves the complex mixed condensation of steam and non-condensable gases. This process couples multi-physical phenomena—gas flow, liquid film dynamics, phase change, and non-condensable gas accumulation—making accurate prediction challenging. To better understand the underlying mechanisms, this paper develops a practical CFD simulation scheme. The scheme strongly couples the Species Transport model and the Eulerian-wall-film (EWF) model via User-Defined Functions (UDFs) to simulate condensate generation, inter-tube migration, and interphase transfer. Its reliability is validated through grid independence tests and comparisons with theoretical and experimental data. Using this model, the effects of inlet velocity, temperature difference, and non-condensable gas mass fraction are analyzed. Results indicate that higher inlet velocity significantly enhances heat and mass transfer, with the average wall heat transfer coefficient stabilizing at high velocities. While a larger temperature difference increases total heat transfer, its marginal benefit decreases, accompanied by reduced efficiency. A high non-condensable gas mass fraction severely inhibits condensation. Furthermore, the outer wall heat transfer coefficient of the tube bundle is highly non-uniform, with the liquid film thickness varying by over two orders of magnitude. This study provides theoretical and numerical insights for the optimal design and operation of falling film condensers. Full article
(This article belongs to the Section Chemical Processes and Systems)
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25 pages, 5276 KB  
Review
Progress and Perspectives on Erosion in Circulating Fluidized Bed Boilers: Mechanisms, Numerical Simulation, and Mitigation Strategies
by Ruiqi Bai, Tuo Zhou, Tong Wang, Xinyun Wan, Xin Meng, Man Zhang and Hairui Yang
Processes 2026, 14(5), 860; https://doi.org/10.3390/pr14050860 - 8 Mar 2026
Viewed by 352
Abstract
Erosion is widely encountered in circulating fluidized bed (CFB) boilers. Investigations into erosion mechanisms and mitigation strategies are essential for improving the operational reliability and reducing economic losses. This paper presents a bibliometric analysis and review of recent progress in erosion-related studies for [...] Read more.
Erosion is widely encountered in circulating fluidized bed (CFB) boilers. Investigations into erosion mechanisms and mitigation strategies are essential for improving the operational reliability and reducing economic losses. This paper presents a bibliometric analysis and review of recent progress in erosion-related studies for CFB boilers, identifying three main research hotspots: CFD-based erosion prediction from flow dynamics, anti-wear coatings from materials science that consider chemical corrosion, and boiler design adaptations for biomass. Building upon classical studies on solid particle erosion mechanisms and accounting for the high-temperature and reactive chemical environments characteristic of CFB boilers, the erosion mechanisms in CFB boilers are systematically summarized. It is revealed that particle flow parameters dominate the erosion process, coupled with chemical corrosion. Subsequently, the application of computational fluid dynamics (CFD) methods to erosion prediction and mitigation in CFB boilers is reviewed, and the characteristics of various anti-wear techniques are discussed. It is found that CFD can serve as an effective tool for the design of anti-wear techniques; however, the design must account not only for erosion resistance but also for the resulting impacts on boiler heat transfer and thermal inertia. Finally, perspectives and future research directions for erosion studies in CFB boilers are outlined. Full article
(This article belongs to the Special Issue Simulation of Particle Flow and Discrete Element)
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29 pages, 6223 KB  
Article
Distinguishing Process Faults from Model Drift Through Variable Contribution Analysis: A Novel Perspective on Anomaly Diagnosis
by Thiago K. Anzai and José Carlos Costa da Silva Pinto
Processes 2026, 14(5), 859; https://doi.org/10.3390/pr14050859 - 7 Mar 2026
Viewed by 544
Abstract
Conventional anomaly diagnosis methods often treat process faults and model drift as distinct, independent issues: anomalous behavior is attributed to process problems, whereas drift is seen as a secondary concern. This traditional perspective neglects the fact that, when a fault is detected, the [...] Read more.
Conventional anomaly diagnosis methods often treat process faults and model drift as distinct, independent issues: anomalous behavior is attributed to process problems, whereas drift is seen as a secondary concern. This traditional perspective neglects the fact that, when a fault is detected, the first diagnosis that must be provided regards the source of the observed deviation: a process fault or a model malfunction. In this context, the present study tackles this fundamental diagnosis problem, proposing that effective anomaly diagnosis should distinguish process faults from model inadequacies originating from operational changes. To address this challenge, the Nearest Normal Value (NNV) contribution analysis technique was developed to quantify individual variable contributions through counterfactual analysis. Unlike conventional diagnostic methods that rely on static references, the NNV technique provides contribution profiles that characterize the operational state dynamically. The methodology was validated using three distinct datasets, including actual operational data from an oil production system. On real data, the normalized dispersion index (S) decreased from 0.92 to 0.58 during a documented fault (37% change), whereas it changed from 0.76 to 0.63 during an operating mode shift (17% change), showing, thus, distinct contribution signatures for faults versus drift-related regime changes. The findings suggest that incorporating the proposed approach into anomaly diagnosis systems could reduce false alarms and improve diagnostic accuracy in dynamic industrial environments where operating conditions evolve over time. Full article
(This article belongs to the Section Process Safety and Risk Management)
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15 pages, 5821 KB  
Article
Research on Gravity Displacement Windows in Fractured Carbonate Reservoirs
by Zhenyu Tao, Guoting Wang, Haoyuan Zhong, Chuanxi Wang and Chengzhou Jiang
Processes 2026, 14(5), 858; https://doi.org/10.3390/pr14050858 - 7 Mar 2026
Viewed by 241
Abstract
Carbonate reservoirs, characterized by extensive fractures and cavities, are prone to gravity displacement during drilling when the bottom-hole pressure approaches equilibrium. This phenomenon, driven by density differences between drilling and formation fluids, can result in simultaneous overflow and leakage, posing significant well control [...] Read more.
Carbonate reservoirs, characterized by extensive fractures and cavities, are prone to gravity displacement during drilling when the bottom-hole pressure approaches equilibrium. This phenomenon, driven by density differences between drilling and formation fluids, can result in simultaneous overflow and leakage, posing significant well control risks such as kicks or blowouts. The occurrence of gravity displacement downhole makes its timely detection through conventional annular flow monitoring techniques challenging. This study investigates the triggering conditions and safe density window for gravity displacement in fractured and cavernous formations. Through theoretical analysis and experimental simulation, we examined the displacement mechanisms in both fractured and cavernous conditions. Computational fluid dynamics (CFDs) simulations were used to validate critical fluid column heights for fractured formations and the proposed safe density window. Based on these findings, practical methods to mitigate the hazards associated with gravity displacement overflow are proposed. The results offer valuable guidance for the field identification and mitigation of such incidents, contributing to managed pressure drilling and enhancing drilling safety in complex carbonate reservoirs. Full article
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22 pages, 3529 KB  
Article
Particle Movement Mechanism of Wheat Particles in a 90° Bend of a Pneumatic Conveying System
by Dongming Xu, Yongxiang Li, Xuemeng Xu and Yongyu Zhang
Processes 2026, 14(5), 857; https://doi.org/10.3390/pr14050857 - 7 Mar 2026
Viewed by 331
Abstract
To investigate the motion mechanism and kinetic energy loss characteristics of wheat particles in a horizontal–vertical upward bend pipe, different curvature radii, gas velocities, and particle mass flow rates are used to study changes in particle velocity, the inter-particle contact force, and the [...] Read more.
To investigate the motion mechanism and kinetic energy loss characteristics of wheat particles in a horizontal–vertical upward bend pipe, different curvature radii, gas velocities, and particle mass flow rates are used to study changes in particle velocity, the inter-particle contact force, and the particle–wall contact force in this study. The results indicate that larger curvature radii weaken the inter-particle contact force. The velocity difference between particles inside and outside of the bend first increases and then decreases at the elbow. Increasing the gas velocity increases the particle velocity and the particle–wall contact force. It also enlarges the velocity gap between the inner and outer particles of the bend, while weakening the inter-particle contact force. With an increase in the mass flow rate, the particle–wall contact force gradually rises at 0–30° of the bend, and then gradually falls at 30–90°. Meanwhile, the inter-particle contact force is enhanced. A higher gas velocity leads to a greater loss of particle kinetic energy caused by collisions. The velocity difference exhibited by particles on the inner and outer sides of the bend remains basically unchanged. The maximum inter-particle and particle–wall contact force is around the 30° bend angle. Full article
(This article belongs to the Section Energy Systems)
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21 pages, 2520 KB  
Article
Combined Effect of Environmental pH and Pulsed Electric Fields on Bacillus Coagulans Vegetative Cells Inactivation
by Varvara Andreou, Ioannis Stavrakakis, Marianna Giannoglou, Petros Taoukis and George Katsaros
Processes 2026, 14(5), 856; https://doi.org/10.3390/pr14050856 - 7 Mar 2026
Viewed by 354
Abstract
The aim of this study was to model the inactivation of Bacillus coagulans vegetative cells subjected to thermal processing (60–90 °C, 1–30 min) and pulsed electric fields (PEF) (11, 15, and 20 kV/cm, up to 0.12 s, 20 Hz, 15 μs pulse width) [...] Read more.
The aim of this study was to model the inactivation of Bacillus coagulans vegetative cells subjected to thermal processing (60–90 °C, 1–30 min) and pulsed electric fields (PEF) (11, 15, and 20 kV/cm, up to 0.12 s, 20 Hz, 15 μs pulse width) at different pH environments (4.0 to 7.0) and in real food matrices (peach puree and carrot juice). Microbial survival data were successfully described using the Gompertz model. Thermal experiments confirmed the high heat resistance of B. coagulans, with maximum survival observed at pH 5.0–6.0. PEF treatments were effective in inactivating vegetative cells, with more intense PEF conditions leading to faster inactivation. Complete inactivation was achieved in less than 15 ms at low pH (4.5), while more than 120 ms was required at pH 6.0. Preheating samples to 50–60 °C prior to PEF significantly reduced the PEF processing time needed for full inactivation, by approximately 88%. In food matrices, the inactivation rate in peach puree was twice as high as in carrot juice, but up to 8 times lower than in buffer solutions. Cells were inactivated twice as fast in peach puree as in carrot juice. This study provides quantitative technical parameter references for optimizing non-thermal processing technologies for acidic/weakly acidic fruit and vegetable products. Full article
(This article belongs to the Section Food Process Engineering)
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22 pages, 2122 KB  
Article
Anaerobic Digestion of Soluble Organic Fraction of Municipal Solid Waste Under Inhibition Conditions: Analysis and Control
by René Alejandro Flores-Estrella, Rubén Fernando Gutiérrez-Hernández, Hugo Alejandro Nájera-Aguilar, José Humberto Castañon-Gonzalez, José Luis Cabellos, Edna Ríos-Valdovinos and Abumalé Cruz-Salomón
Processes 2026, 14(5), 855; https://doi.org/10.3390/pr14050855 - 7 Mar 2026
Viewed by 355
Abstract
A nonlinear dynamical model for anaerobic digestion (AD) of the soluble organic fraction of municipal solid waste (OFMSW) is analyzed under inhibition conditions. The model incorporates both the acidogenic and methanogenic stages, accounting for substrate and product inhibition in both microbial consortia. Based [...] Read more.
A nonlinear dynamical model for anaerobic digestion (AD) of the soluble organic fraction of municipal solid waste (OFMSW) is analyzed under inhibition conditions. The model incorporates both the acidogenic and methanogenic stages, accounting for substrate and product inhibition in both microbial consortia. Based on the dynamical properties, three stable equilibria are identified and linked to realistic operating scenarios: washout, acidification, and normal (stable) operation. Control schemes are proposed to regulate the organic substrate concentration and achieve the desired operating conditions. These strategies enhance operational stability under both normal and acidification conditions. A linear proportional-integral (PI) control scheme is designed, along with two tuning approaches to ensure closed-loop stability in the presence of external load disturbances, measurement noise, and substrate and product inhibition. The control schemes achieve, under normal operating conditions, 96% removal of soluble organic substrate and 60% removal of volatile fatty acids; under acidification conditions, 72% substrate removal is attained, with a 152% increase in volatile fatty acids relative to the inlet levels. Accordingly, the proposed model and control scheme offer a promising contribution toward improving the operational stability of AD processes treating OFMSW. Full article
(This article belongs to the Special Issue Process Engineering: Process Design, Control, and Optimization)
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14 pages, 1140 KB  
Article
Combustion Gas Emissions for Wood and Coal Cofiring on Grate Systems in Sub-Arctic Conditions
by David L. Nicholls and Daisy Huang
Processes 2026, 14(5), 854; https://doi.org/10.3390/pr14050854 - 6 Mar 2026
Viewed by 279
Abstract
Wood and coal cofiring holds great potential for reducing greenhouse gas emissions from grate-fired combustion systems, as well as being widely technically feasible. This research was among the first to evaluate CO and NOx levels within grate-fired cofiring at small utility scales. [...] Read more.
Wood and coal cofiring holds great potential for reducing greenhouse gas emissions from grate-fired combustion systems, as well as being widely technically feasible. This research was among the first to evaluate CO and NOx levels within grate-fired cofiring at small utility scales. We evaluated two wood fuel types—high-quality aspen chips and lower-quality pellet mill residues. Each wood fuel was evaluated at two cofiring rates. Over 6 days of testing, CO contents ranged from 40 to 620 ppm, and NOx contents ranged from 82 to 145 ppm. We found statistically significant differences in CO content when comparing low versus high cofiring rates, with high cofiring having greater CO concentrations. Relatively high CO emissions were attributed to greater moisture within the combustion chamber at higher levels of wood. Combustion efficiency versus cofiring rate was generally modeled the best as a quadratic relationship; carbon monoxide content versus cofiring rate was best modeled linearly. There were very few changes in combustion efficiency, fuel handing, or plant operation at the utility scale when cofiring at up to 15 percent of the energy value (versus no cofiring). From an operational standpoint, cofiring was relatively easy to implement and well received by plant managers. Full article
(This article belongs to the Special Issue Advances in Biomass Conversion and Biorefinery Applications)
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24 pages, 2269 KB  
Article
Coordinated Dispatch Strategy for Source-Grid-Load-Storage in Active Distribution Networks Driven by Zero-Carbon Goals
by Yutong Wu, Faju Jin, Changguo Yao, Yi Zheng, Shufang Zhou and Zhe Wu
Processes 2026, 14(5), 853; https://doi.org/10.3390/pr14050853 - 6 Mar 2026
Viewed by 381
Abstract
With the continuous advancement of the construction of new power systems, the coordinated development of source-grid-load-storage has become imperative. This paper proposes a coordinated dispatch strategy for source-grid-load-storage in active distribution networks oriented toward zero-carbon goals. First, this paper introduces the concepts of [...] Read more.
With the continuous advancement of the construction of new power systems, the coordinated development of source-grid-load-storage has become imperative. This paper proposes a coordinated dispatch strategy for source-grid-load-storage in active distribution networks oriented toward zero-carbon goals. First, this paper introduces the concepts of the green electricity index and zero-carbon pathway constraints. Building upon this foundation, a coordinated dispatch model for source-grid-load-storage in active distribution networks is constructed, aiming for optimal economic performance while considering equipment and system operational constraints. On the other hand, this paper employs Information Gap Decision Theory (IGDT) to construct uncertainty sets for renewable energy output and load demand, proposing a comprehensive deviation coefficient calculation method. This approach reduces the conservativeness of dispatch decisions while ensuring their robustness. Considering the nonlinear characteristics of the model, an improved sparrow search algorithm is adopted to enhance solution efficiency. Finally, validation using the IEEE-33 node test system demonstrates the effectiveness and feasibility of the proposed method. Full article
(This article belongs to the Special Issue Advances in Carbon-Energy Perception and Low-Carbon Optimal Energy System Operation)
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10 pages, 659 KB  
Article
Computational Fluid Dynamics in Scale-Up Plasmonic-Doped Semiconductor Metal Oxide Nanocrystal Oleyl Alcohol Reaction Batch Mixture Dispersions
by Sang Jun Lee, Do Yoon Park and Shin Hum Cho
Processes 2026, 14(5), 852; https://doi.org/10.3390/pr14050852 - 6 Mar 2026
Viewed by 365
Abstract
Scale-up synthesis in doped semiconductor metal oxide plasmonic nanocrystal batch reaction dispersion mixture processes often leads to significant changes in rheological behavior and flow characteristics, especially when using high-viscosity organic media. In this study, the rheological and hydrodynamic properties during the scale-up of [...] Read more.
Scale-up synthesis in doped semiconductor metal oxide plasmonic nanocrystal batch reaction dispersion mixture processes often leads to significant changes in rheological behavior and flow characteristics, especially when using high-viscosity organic media. In this study, the rheological and hydrodynamic properties during the scale-up of a nanocrystal dispersion system where oleyl alcohol was used as a reaction solution medium were investigated. The flow field in a mechanically stirred 4 L pilot reactor was numerically analyzed using ANSYS Fluent based on experimentally obtained viscosity and density data of oleyl alcohol. At 290 °C, coincident with the nucleation and growth of plasmonic-doped metal oxide nanocrystals, solvent viscosity decreases to a corresponding Reynolds number of 9.2 × 105, indicating that the dramatic viscosity reduction in oleyl alcohol above synthetic temperature batch reaction conditions drives a sharp increase in Reynolds number into a strongly turbulent mixing regime at synthetically relevant temperatures. The simulation results revealed that the scale-up process induces notable variations in shear rate distribution, local turbulence intensity, and overall mixing efficiency. These findings suggest that understanding rheological transitions under scale-up conditions is essential for optimizing nanoparticle synthesis and dispersion uniformity in industrial applications. Full article
(This article belongs to the Special Issue Metal Oxides in Heterogeneous Oxidation Catalysis)
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22 pages, 8861 KB  
Article
Quantitative Identification of Lithology and Gas-Bearing Properties of Carbonate Reservoirs in the Majiagou Formation, Central Shaanbei Slope, Ordos Basin
by Pengfei Wu, Congjun Feng, Xiaohong Deng, Xinglei Song, Tongyang Lou and Mengsi Sun
Processes 2026, 14(5), 851; https://doi.org/10.3390/pr14050851 - 6 Mar 2026
Viewed by 346
Abstract
The identification of lithology and fluids in reservoirs is the key to the quantitative characterization of gas reservoirs. However, the Ma541 Member of the Majiagou Formation in the Ordos Basin is characterized by strong reservoir heterogeneity, variable lithologic components and complex [...] Read more.
The identification of lithology and fluids in reservoirs is the key to the quantitative characterization of gas reservoirs. However, the Ma541 Member of the Majiagou Formation in the Ordos Basin is characterized by strong reservoir heterogeneity, variable lithologic components and complex gas–water relationships. This leads to severe overlapping of conventional logging responses, posing significant challenges to detailed reservoir evaluation. Taking the Ma541 Member in the central Shaanbei Slope of the Ordos Basin as the research object, this study adopts the logging curve superposition and reconstruction method to quantitatively identify reservoir lithology and fluid properties, and establishes a set of identification standards for lithology-fluid logging curve superposition and reconstruction. The results show that the lithology identification plate constructed by introducing new parameters eliminates dimensional differences and effectively highlights the response characteristics of different lithologies. It can rapidly and effectively identify limestone, limy dolomite, dolomite, argillaceous dolomite, and mudstone with an identification accuracy exceeding 90% and an average accuracy of over 92%. In terms of fluid identification, the constructed ΔΦ3–ΔΦ4–ΔΦ5 3D plate successfully achieved the stereoscopic differentiation of gas layers, gas-bearing water layers, water layers, and dry layers. The gas layer identification accuracy reached 93.9%, which is significantly superior to the traditional 2D crossplot method. Applying this model to the plane prediction of lithology in the Ma541 Member of the study area, it was found that the lithology distribution features “pure in the east and mixed in the west.” The central-eastern and southeastern parts of the study area mainly develop high-quality dolomite and limy dolomite reservoirs, making them favorable areas for natural gas exploration. This study provides effective technical support for the quantitative identification of lithology and fluids in non-cored well sections and improves regional exploration and development efficiency. Full article
(This article belongs to the Special Issue Advanced Technologies for the Exploration of Conventional and Unconventional Oil and Gas)
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23 pages, 1415 KB  
Review
Composting of Biodegradable Packaging Materials: A Review of Available Technology for Biopolymer Degradation
by Tea Sokač Cvetnić, Frédéric Debeaufort, Nasreddine Benbettaieb, Iva Pavlinić Prokurica and Mia Kurek
Processes 2026, 14(5), 850; https://doi.org/10.3390/pr14050850 - 6 Mar 2026
Viewed by 537
Abstract
Over the past few decades, the extensive use of plastics has led to significant environmental challenges due to their limited biodegradability and long-term persistence. Consequently, biodegradable materials have attracted considerable attention as sustainable alternative solutions to mitigate these environmental concerns. Also, the use [...] Read more.
Over the past few decades, the extensive use of plastics has led to significant environmental challenges due to their limited biodegradability and long-term persistence. Consequently, biodegradable materials have attracted considerable attention as sustainable alternative solutions to mitigate these environmental concerns. Also, the use and disposal of these materials present some sustainability challenges. Biopolymers have some advantages over standard polymers, such as biodegradability, non-toxicity and environmental sustainability, and they can be used in various industries. Taking into account the fact that the biopolymers are produced by living organisms and microorganisms, they are considered as the natural materials that can be composted. This review paper explores the increased demand for biopolymers and summarizes their benefits along with application. Overall, the focus is on the composting process as the promising sustainable technology for recovery of biodegradable waste as well as for biopolymers. Also, some biopolymers and their degradation in different conditions are presented, and the biodegradation test methods for these materials are mentioned in accordance with relevant international standards. This review aims to provide a comprehensive overview of current developments and future development directions for the biopolymer field. Full article
(This article belongs to the Special Issue Innovative Bioreactor Design and Advanced Optimization Strategies for Biorefineries and Bioprocessing)
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