Search Results (154)

Supercritical CO₂ injection can mitigate depletion-induced deterioration of shale oil, but the relationship between laboratory-scale fluid-property changes and field-scale recovery remains insufficiently understood. This study integrates time-lapse produced-oil characterization, high-pressure PVT experiments, whole-hydrocarbon gas chromatography, and compositional reservoir simulation for the Mabei shale oil reservoir. From October 2023 to October 2025, the viscosity of dehydrated and degassed produced oil at 80 °C increased from 20.93 to 56.8 mPa·s, accompanied by depletion of light hydrocarbons and enrichment of heavy components, indicating progressive compositional deterioration during depletion. At 106.75 °C and 65.07 MPa, increasing the added CO₂/oil molar ratio from 0 to 80% reduced live-oil viscosity from 9.7841 to 3.8470 mPa·s and density from 0.8326 to 0.7897 g/cm³. Most viscosity, density, and oil-phase compositional changes occurred within the first 6 h in the closed, continuously stirred PVT cell. CO₂ contact preferentially transferred C3–C7 hydrocarbons out of the analyzed oil-rich phase, resulting in relative enrichment of C15–C37 components in the residual oil. The history-matched compositional model showed that CO₂ improved reservoir pressure maintenance and expanded low-viscosity regions primarily along fracture-connected flow paths, although the incremental response became limited between the 20 and 25% cases. Regional compositional analysis further demonstrated that strongly CO₂-contacted residual oil became heavier, whereas the produced oil was enriched in mobilized light and intermediate hydrocarbons. These results establish a consistent laboratory-to-field interpretation of CO₂-induced compositional redistribution and provide a basis for optimizing CO₂-assisted development in deeply buried shale oil reservoirs. CO₂-induced asphaltene precipitation/deposition and the associated permeability impairment were not measured or represented in the numerical model. Therefore, the reported recovery response reflects CO₂–oil property and transport effects in the absence of solid-phase formation damage. Full article

A new efficient coupled process to produce green solvent ethyl propionate was developed, which involved a fixed-bed reactor and pervaporation membrane separation. Firstly, the esterification reaction alone was investigated to explore reaction conditions and kinetics. Secondly, the pervaporation alone was investigated to explore separation conditions and the separation performance of pervaporation membranes. Then, the esterification reaction, coupled with pervaporation to enhance the reaction process, was investigated. Finally, the mathematical model of the esterification reaction, coupled with the pervaporation process, was established. The results showed that the conversion of ethanol reached 78.4% within 5 h. The reaction kinetics were obtained based on the pseudo-homogeneous (PH) model. Under the condition of a circulation flow rate of 100 L/h, the influence of concentration polarization could be well overcome, and a high level of pervaporation could be achieved. The pervaporation coefficients of the four-component system were obtained based on Fick’s law. The dehydration rate increased significantly with the increase in pervaporation temperature, which could effectively enhance the esterification reaction. The model could well predict the experimental results, and the experimental results were in good agreement with the theoretical calculations. Full article

The solvent dehydration tower in Purified Terephthalic Acid (PTA) production is characterized by strong multivariable interactions, slow vapor–liquid dynamics, and high sensitivity to upstream disturbances, often limiting the effectiveness of conventional proportional–integral (PI) control. Despite increasing interest in model predictive control (MPC) for separation systems, its application to industrial-scale PTA dehydration under realistic disturbance scenarios and operational constraints remains limited. This study develops a 5 × 5 multivariable model predictive control (MMPC) strategy for an industrial PTA dehydration tower based on a validated nonlinear first-principles UniSim^® Design R500 model and a complete 25-element first-order plus dead time (FOPDT) prediction model identified from systematic dynamic tests. The proposed MMPC was evaluated against the existing industrial PI controller under four representative industrial disturbance scenarios, including feed temperature, feed flow rate, and feed composition variations in two inlet streams. The results show that the proposed MMPC reduced the Integral Absolute Error (IAE) and Integral Squared Error (ISE) by approximately 87–100%, depending on the disturbance scenario and controlled variable. The greatest improvement was obtained under feed composition disturbances, where the MMPC achieved IAE and ISE values of 117.9 and 21.5 for Stream 1, and 8.1 and 0.1 for Stream 2, respectively. The only exception was the inlet temperature disturbance, for which the existing industrial PI controller remained slightly superior because of the predominantly local thermal dynamics and relatively weak process interactions. These results demonstrate that MMPC is particularly effective for strongly coupled multivariable disturbances and provide a practical framework for implementing advanced control in industrial PTA dehydration systems using validated process models. Full article

Carbon capture and storage (CCS) technology can play an important role in meeting net-zero ambitions; however, its successful deployment depends on the transport and storage infrastructure for CO₂, as they are the backbone of the carbon management industry. Among the key integrity threats for dense-phase and supercritical CO₂ pipelines, acid precipitation or dropout in CO₂-rich streams containing reactive impurities (SO_x, NO_x, H₂S, H₂O, O_2, etc.) is one of the most serious. These impurities can alter phase behavior, promote formation of highly acidic liquid-phase condensates, and trigger severe localized corrosion and rapid wall-thickness loss. This review focuses on understanding the effects of specific combinations of impurities on CO₂ phase envelopes, acid formation, and corrosion mechanisms in pipelines under realistic flow and operating conditions. It further assesses mitigation and design strategies, including impurity specification and control, deep dehydration, operational envelope management, corrosion-resistant alloys, internal linings and advanced coatings, and emerging modeling tools for predicting corrosive dropout. The knowledge gap in long-term performance under multi-impurity conditions, thermo-hydraulic transients, and coupled corrosion damage is highlighted. Additionally, the importance of future experimental, modeling, and standards development work to enable safe, cost-effective material solutions for CCS technology deployment is proposed. Full article

Channeling control remains the most critical challenge in fluid injection for enhanced oil recovery (EOR). Polymer gels are widely applied in channeling control due to their capability to alter the permeability of flow channels. However, high temperature and high salinity lead to low efficiency of gels, causing injected fluid to flow away through high-permeability channels and thereby hindering petroleum production. To address this, this study developed and applied a new gel, synergistically combining a tailored temperature-/salt-resistant co-polymer with an optimized cross-linker. Laboratory evaluation experiments demonstrated that this gel could resist high temperature (>130 °C) and high salinity (>20 × 10⁴ mg/L), exhibit remarkable stability (gel dehydration rate <20% after 100 days aging), and achieve a plugging rate exceeding 98%. A pilot field case, designed based on laboratory outcomes, was successfully implemented in the Gasikule Block of the Qinghai Oilfield. The field validation indicated that this advanced gel system effectively restored reservoir pressure, thereby establishing critical prerequisites for subsequent EOR operations. This study advances the application of polymer gels in channeling control, demonstrating their superior performance and broad perspective in enhancing channeling control. Full article

Aiming at the characteristics of high viscosity and poor fluidity of high waxy ordinary heavy oil, a Janus silica-based nanosheet composite viscosity reducer was designed and prepared in this paper. The viscosity reducer was assembled by asymmetric Gemini viscosity reducer and silica nanosheets through dehydration condensation reaction, and its structure was verified by FT-IR, ¹HNMR, XPS and DLS. The viscosity reduction performance, emulsion stability, interfacial tension and flow performance of the viscosity reducer were systematically evaluated by taking heavy oil with wax content of 35.7% and viscosity of 237 mPa·s at 30 °C as the research object. The results showed that, at an oil-to-viscosity-reducer-solution volume ratio of 3:7 and a viscosity reducer mass fraction of 0.3%, the maximum viscosity reduction rate reached 94.5% at 30 °C, calculated relative to the viscosity of the dehydrated original heavy oil. The oil–water interfacial tension was significantly reduced, and the 24 h bleeding ratio, defined as the volume percentage of separated water relative to the initial aqueous phase volume, was only 7.3%, indicating good emulsion stability. The core flow experiment shows that the resistance coefficient is reduced to the lowest at 0.3% concentration, and the seepage capacity is significantly improved. The analysis of total hydrocarbon gas chromatography showed that the content of high-carbon wax components in the C₂₃-C₃₀ range decreased by 4.79 percentage points after treatment, indicating that the viscosity reducer preferentially interacted with high-carbon wax molecules and promoted wax-crystal dispersion, thereby weakening the three-dimensional wax-crystal network. The viscosity reducer has the synergistic effect of dispersing wax crystals, reducing interfacial tension and stabilizing emulsification, which provides a low-cost and high-performance technical approach for the efficient exploitation of high waxy ordinary heavy oil. Full article

Facing the harsh offshore environment characterized by severe space constraints and continuous platform motion, this study develops an optimized rotating packed bed (RPB) for compact and robust triethylene glycol dehydration. Through integrated experimental and computational investigation, the concentric-ring rotor was identified as superior among four configurations, consistently achieving dehydration equilibrium above 80% under lean TEG conditions. CFD analysis revealed its fundamental mechanism: synergistic matching between the centrifugal force field and annular flow paths yields the most uniform liquid distribution. This enabled the establishment of a strong predictive correlation (R² = 0.935) between simulated liquid uniformity and experimental dehydration performance. Guided by flow field diagnostics, targeted structural optimizations increased dehydration equilibrium from 86.1% to 92.25% while reducing system pressure drop by 73%. Parametric studies defined an optimal operating envelope at a gas-to-liquid ratio of 60:1 and system pressure of 2 MPa, achieving peak efficiency of 96.42% with robust performance across 50–150% load variations. This work demonstrates a simulation-guided pathway for intensifying separation processes, providing a validated framework for designing marine-adapted dehydration technology. Full article

Aim: We aimed to provide a structured ex vivo protocol for cardiopulmonary micro-CT that combines gelatin–barium sulfate (gelatin–BaSO₄) contrast medium with agar embedding in neonatal canine cardiopulmonary specimens. Materials and Methods: Heart–lung specimens from 23 puppies that died shortly after birth were collected, stored at −20 °C, and then slowly thawed prior to imaging. Before perfusion, body mass and heart–lung complex mass were recorded. Body mass ranged from 140 to 951 g, and heart–lung complex mass ranged from 1.2 to 51.2 g. The cranial and caudal venae cavae, the brachiocephalic trunk, and the left subclavian artery were ligated. A catheter was introduced into the thoracic aorta. Contrast was prepared by dissolving porcine gelatin in hot water and mixing with a commercial BaSO₄ suspension. The mixture was maintained at a warm temperature to remain free-flowing and was delivered at low pressure until uniform opacification of the coronary and pulmonary arteries was observed. After in situ gelation, the organs were embedded in warm agar and sealed to limit motion and dehydration. Scans were performed on a benchtop system (120 kV, ~83 µA, ~1200 projections, ~2 s exposures; voxel ~40 µm). Reconstruction was performed in XMReconstructor, with post-processing in Falcon and RadiAnt. The reconstructed micro-CT datasets were reviewed anatomically by a medical cardiologist and a veterinary cardiologist, whereas vascular filling was evaluated semi-quantitatively by three observers with expertise in veterinary anatomy and cardiology. Results: In all specimens examined, the main coronary artery course was assessable. Conclusions: The gelatin–BaSO₄ contrast medium combined with agar immobilization provides a simple, lead-free, and affordable approach for structured cardiopulmonary micro-CT in very small post-mortem specimens. In the examined specimens, the workflow provided visually consistent low-pressure vascular opacification without gross evidence of vessel rupture or motion-related acquisition failure under the conditions of this study. Practical mitigations included temperature/viscosity control, avoidance of phosphate buffers, container sealing, and minimization of particle aggregation, bubbles, and dehydration. The protocol may complement conventional autopsy in very small post-mortem specimens in similar ex vivo research settings. Full article

This study investigates the separation performance of transformer oil–water mixtures using gravity separation and chemical demulsification. The synthetic emulsion had an initial oil concentration (C₀) of approximately 246,000 mg/L. For gravity separation, the effects of compartment volume ratio, influent flow rate, initial water level, and oil discharge strategy were systematically evaluated. Under optimal conditions (volume ratio 2:1:1, flow rate 0.0055 L/s, initial water level 5 cm), the effluent oil concentration was reduced to as low as 0.020 mg/L, corresponding to a removal efficiency higher than 99.99%. For chemical demulsification, polyaluminum chloride (PAC), polyferric sulfate (PFS), polyacrylamide (PAM), and an organosilicon polyether demulsifier (MCL-D) were tested. The effects of pH, dosage, and temperature on demulsification efficiency (DE) and dehydration rate (DR) were investigated. Under optimal conditions (pH 3–5, dosage 300 mg/L, temperature 50 °C), MCL-D achieved the best performance, with a DE of 95.09% and a DR of 99.50%. Overall, gravity separation is effective for removing free and dispersed oil with low operational cost, whereas chemical demulsification is more suitable for treating stable emulsified oil. The combination of these two methods provides an efficient strategy for the treatment of transformer oil-containing wastewater. Full article

The paper utilizes the synergy of vibration and hot air flow to form a composite force field, and low-quality fine coal with viscous moisture is subjected to ash removal. The vibration signals of the bed surface at different positions are collected online using an accelerometer, and the dominant force affecting the vibration behavior of the bed is analyzed using signal time-domain analysis. By examining the impact of the synergy between vibration and airflow on the ash removal effect of low-quality, viscous moisture coal, the response of the drying and sorting behavior of low-quality fine coal to this synergy is elucidated. Based on the study of the experimental results of dehydration and ash removal of −6 + 1 mm fine coal, under the synergy of temperature and load force field, when the air flow temperature is 90 °C, v = 0.65 m/s, and f = 20 Hz, the collision force range between particles is 120 nN–370 N, which is different from that between particles. The liquid bridge force is large, which can achieve the fracture of liquid bridges between particles and strengthen the loose fluidization of particles. In addition, based on the study of the vibration characteristics of the bed surface at different positions, the vibration along the y-axis direction plays a dominant role in the density segregation behavior of the bed particles. With the increase in gas velocity and vibration frequency, the ash content of the selected clean coal exhibits a trend of first decreasing and then increasing. At the same time, the ash segregation degree initially increases and then decreases. Moreover, under the conditions of v = 0.65 m/s and f = 20 Hz, the separation effect of fine coal is the best. The separation accuracy E values of 1–6 mm without fine particles are 0.06 g/cm³, and the ash content of the clean coal is 12.55%. Full article

This work presents a mechanistic modeling approach for simulating methane emissions from triethylene glycol (TEG) dehydrators used in oil & gas (O&G) operations. The model was developed as a modular component of the Mechanistic Air Emissions Simulator (MAES) tool, incorporating species-specific absorption and emission dynamics through two-level, second-order polynomial regression (PR) models trained on ProMax simulation data: (1) species-level regression models that track the transfer rates of individual gas species within the dehydrator unit streams, and (2) outlet flow stream regression models that predict the fraction of inlet gas distributed among the outlet streams of the dehydrator unit. These behaviors were characterized over a range of glycol circulation ratios, wet gas pressures, and temperatures. The model was validated using root mean square error (RMSE) analysis. The species-level PR achieved low root mean square error (RMSE) values (<0.03) for light hydrocarbon species across all dehydrator components, ranging from 0.0009 for methane to 0.029 for normal pentane. Similarly, the outlet-level PR yielded RMSE values below 0.002 for the dry gas fraction, 0.001 for the flash tank fraction, and 0.002 for the still vent fraction, demonstrating strong agreement between predicted and reference ProMax values. When deployed at field facilities, the model significantly improved MAES-simulated dehydrator emissions, revealing that gas-assisted glycol pump emissions are the dominant contributors to both dehydrator-level and site-level methane emissions under uncontrolled conditions. Further analysis of the 154 dehydrator units reported by operators under the AMI 2024 project showed that 54 units (31%) used gas-driven glycol pumps, of which 6 units (11%) operated with uncontrolled flash tanks, and 22 units (40.7%) were identified as potentially oversized. Of the six dehydrator units with uncontrolled gas-assisted pumps, pump emissions accounted for 90.25% of total dehydrator emissions and 63.10% of total site-level emissions. These findings highlight substantial opportunities for emissions mitigation through equipment upgrades. Full article

Ginger (Zingiber officinale) is an essential crop that is widely cultivated for its medical and culinary value. In 2023, ginger was considered one of the highest value herbs, with approximately 9089.85 tons produced in Malaysia. However, the ginger cultivation suffers from plant diseases, which lead to plant death and eventually cause crop losses. Furthermore, the lack of studies in ginger leaf disease detection using deep learning techniques is a limitation that hinders the early diagnosis and management of ginger diseases. To address this limitation, we collected 968 ginger plant images cropped into single leaf images and labelled into 4 classes: leaf blight, dehydrated, damaged pest, and healthy, using the Encordplatform. The generated dataset consisted of 4033 leaf images. Through data augmentation, the dataset was expanded into 10,910 leaf images to improve the model’s generalization. As deep learning techniques are popular in plant disease detection, we evaluated several popular pre-trained models using TensorFlow and PyTorch libraries and compared the performance with that of other models. For all of these models, the same settings were applied with minimal modification to the model’s layers. Among the compared models, EfficientNetB3 achieved the highest accuracy of 94.3% in detecting ginger leaf diseases. It surpassed other models and exceeded the next-best model in this experiment, MobileNetV2, which achieved 89.66% accuracy, by 4.64%. Full article

The increasing energy demand and global dependence on conventional fuels have resulted in severe greenhouse gas (GHG) emissions, necessitating the development of sustainable bioenergy alternatives. Algal is recognized as a promising feedstock for the production of fourth-generation biofuels. This study optimizes catalytic pyrolysis of Arthrospira platensis for bio-oil production via a dual-bed catalyst system of iron-impregnated dolomite (Fe/DM) and a copper-impregnated spent fluid catalytic cracking catalyst (Cu/sFCC). A face-central composite design (FCCD) and response surface methodology (RSM) were used for the delineation of optimal conditions, ensuring that all experimental tests remained within feasible operating conditions of 500–600 °C, a reaction time of 45–75 min, a N₂ flow rate of 50–200 mL/min, and a catalyst loading of 5–20 wt%. The bio-oil yield was maximized at 39.73 ± 2.86 wt% at 500 °C for 45 min, a N₂ flow of 50 mL/min, and 5 wt% catalyst loading to feedstock with a 0.4:0.6 mass ratio of Fe/DM: Cu/sFCC. The dual-catalysts combined Brønsted and Lewis acid sites enhanced the catalytic activity, which promotes the cleavage of carbon–carbon and carbon–hydrogen bonds, including the mechanism of catalytic pathways such as dehydration, decarboxylation, oligomerization, aromatization, and further cracking reactions, and was successful in converting high-molecular-weight molecules into lighter hydrocarbons and significantly improving product selectivity, demonstrating a highly effective pathway for producing high-quality sustainable biofuel. Full article

In response to the requirements of wellbore plugging and lost circulation control, this study designed and prepared a new type of thixotropic polymer gel system. The optimal formula was obtained through systematic screening of the types and concentrations of high molecular polymers, cross-linking agents, flow pattern regulators, and resin curing agents. Comprehensive characterization of the gel’s gelling performance, thixotropic properties, high-temperature stability, shear resistance, and plugging capacity was conducted using methods such as the Sydansk bottle test, rheological testing, high-temperature aging experiments, plugging performance evaluation, as well as infrared spectroscopy, nuclear magnetic resonance, and thermogravimetric analysis, and its mechanism of action was revealed. The results show that the optimal formula is 1.2% AM-AA-AMPS terpolymer + 0.5% hydroquinone + 0.6% S-Trioxane + 0.8% modified montmorillonite + 14% modified phenolic resin. This gel system has a gelling time of 6 h, a gel strength reaching grade H, and a storage modulus of 62 Pa. It exhibits significant shear thinning characteristics in the shear rate range of 0.1~1000 s⁻¹, with a viscosity recovery rate of 97.7% and a thixotropic recovery rate of 90% after shearing. It forms a complete gel at a high temperature of 160 °C, with a dehydration rate of only 8.5% and a storage modulus retention rate of 80% after aging at 140 °C for 7 days. Under water flooding conditions at 120 °C, the converted pressure-bearing capacity per 100 m reaches 24.0 MPa. Mechanism analysis confirms that the system forms a stable composite network through the synergistic effect of “covalent cross-linking—hydrogen bonding—physical adsorption”, providing a high-performance material solution for wellbore plugging in high-temperature and high-salt environments. Full article

The high incidence of cardiovascular disease and the early failure of bioprosthetic valves due to calcification have driven the development of anti-calcification technologies. As a new storage technology, drying treatment is expected to delay the calcification process by reducing glutaraldehyde residues. However, the effects of drying treatment on the mechanical properties and valve functions of bovine pericardial materials are still unclear. The objective of this study is to evaluate the influence of drying and rehydration treatments on the mechanical integrity and geometric properties of bovine pericardium and the hemodynamic performance of bioprosthetic valves made with these tissues. Cross-linked bovine pericardial samples (n = 15) were divided into three groups—wet (control group progressed with normal glutaraldehyde), dehydrated (ethanol–glycerol dehydration), and rehydration (saline immersion) groups—and the geometric stability and nonlinear mechanical behaviors of the materials were analyzed via thickness measurements and uniaxial and biaxial tensile tests. Quantitative results showed that thickness remained stable across groups (wet: 0.356 ± 0.052 mm; dry: 0.361 ± 0.053 mm; rehydrated: 0.361 ± 0.053 mm, p > 0.05). Elastic modulus values were preserved (wet: 12.5 ± 1.8 MPa; dry: 13.1 ± 2.0 MPa; rehydrated: 12.7 ± 1.9 MPa, p > 0.05), and anisotropy ratio showed no significant changes (1.53 ± 0.06 vs. 1.57 ± 0.07, p > 0.05). The hemodynamic performance of bioprosthetic valves made with these materials was evaluated in vitro using a pulsating flow simulation. Hemodynamic parameters demonstrated excellent preservation: effective orifice area (wet: 2.625 ± 0.11 cm²; rehydrated: 2.585 ± 0.12 cm², Δ = 1.5%, p = 0.32) and regurgitation fraction (wet: 39.35 ± 2.9%; rehydrated: 42.78 ± 3.2%, p = 0.15) showed no statistically significant differences. The geometric properties of the material were not significantly changed by the drying treatment, and the material maintained its nonlinear viscoelastic characteristics and anisotropy. The rehydrated bioprosthetic valves did not differ significantly from those in the wet group in terms of the effective orifice area, regurgitation fraction, and transvalvular pressure difference, and the hemodynamic performance remained stable. Full article