Energy Science & Engineering最新文献

Condensate banking is a key challenge for gas condensate reservoirs with low permeability as it reduces gas relative permeability as much as ~60% near the wellbore. Condensate banking occurs when the bottom-hole pressure in the near-well bore region falls below the dew-point pressure of the gas. This study investigates condensate-banking treatment using a combined low-salinity waterflooding (LSW) and electrokinetic enhanced oil recovery (EK-EOR) techniques. The theoretical framework proposed in this paper is derived from the principles of fluid-rock interaction, electrokinetic phenomena, and water salinity. Methodologically, results from IFT laboratory experiments were fed into simulation models and used to evaluate the effectiveness of LSW-EKEOR treatment. Numerical simulations were performed using a synthetic reservoir model that captures typical reservoir conditions, including pressure, temperature, fluid properties, and rock characteristics. The results show that combining LSW with EKEOR increases condensate recovery by 228%, primarily by reducing gas condensate accumulation—particularly in high-permeability zones. Additionally, the approach suggests a potentially superior environmental performance by lowering the energy required for treatment and reducing chemical use. The discussion explores the broader implications of this technique for future oil recovery processes, emphasizing its potential to reduce operational costs and carbon footprints in mature fields.

Household members relying on wood or charcoal stoves are currently exposed to greenhouse gases like carbon monoxide (CO), carbon dioxide (CO₂), and so on. Measuring CO₂ and CO concentrations helps evaluate the energy efficiency of the charcoal stove and identify opportunities for improvement (it may also help adjust the stove's operation to minimize pollutant emissions and maximize energy efficiency), on the one hand, and helps verify compliance with environmental and safety regulations and standards, on the other hand. We were motivated in this study first of all by the desire to reduce the households' fuel consumption, and to assure the comfort, security, and health of households' members, as well as the desire to preserve fossil resources; and second by the investigation the performance of our cookstove prototype when compared to three (03) other stoves purchased in local market. In this study, we analyzed the carbon dioxide concentration emitted by a more sophisticated improved biomass cookstove, the so called “stove SAG”. Its performances for a Simple Water Heating Test (SWHT) were compared to those of stoves IC, CS and MC available in Cameroonian market. The attractiveness, comfort and security assured by stove SAG as well as its low pollution allows to recommend it for massive use in developing countries in general and particularly in Cameroon.

In the photovoltaic industry, high module efficiency products are preferred in the residential market because these products can be used on the rooftop of houses or buildings with limited surface areas. There are two ways to increase the module efficiency: boosting module output for the same input energy or by reducing inactive area in the modules. When reducing the module size, the space between cells in a string can be eliminated by overlapping them. However, this overlapping areas can cause critical reliability issues such as cell crack, which can lead to decreasing module power during its lamination process. We demonstrate that this type of cell crack on the overlapping area can be resolved by applying wire flattening technology and developing encapsulation materials with the dynamic sheer viscosity data at different temperatures. The combination of the flattening technology and precured high melting index of ethylene vinyl acetate (EVA) are the key technologies, which result in less stress on the overlapped area, eliminate the cell cracks, and finally prevent the future potential reliability issue in the field. The cell overlapping technology presented in this article can be implemented to increase the module efficiency by +0.4%. Additionally, this study can contribute to the development of the high module efficiency module products for larger solar cells, such as M10 and M12 size.

Solar radiation management (SRM) is a geoengineering strategy designed to combat global warming by reflecting sunlight away from Earth, thereby reducing solar heating. While SRM has the potential to lower global temperatures, it's distinct from addressing the root cause of climate change: greenhouse gas emissions. This study utilized system dynamics (SD) modeling to illustrate the relationships between various factors, including Solar Radiation Utilization. Simulation results for Spatial Position, Protection Principles, and Solar Radiation Utilization ultimately demonstrate a gradual increase in Global Warming Mitigation. Our study indicates that infrared-centric solar shielding effectively reduces global warming. We recognize the inherent uncertainties in the precise position and angle of such shielding, so we conducted simulations across two distinct spatial configurations. The comparative statistics from these simulations reveal that Case 2 resulted in a greater maximum value for global warming mitigation. This finding clearly shows the impact that the placement of solar shielding has on its overall effectiveness. Further research could explore optimizing this placement for even more substantial results.

Guangdong Province, a significant wind energy producer in China, is frequently impacted by landing typhoons along its coastal areas. Therefore, it is crucial to analyze the characteristics and influencing factors of wind power generation during typhoons at coastal wind farms in Guangdong. This study examines power generation data from the Lingnan Wind Farm during Typhoon Chaba and calculates indexes including wind shear, temperature and pressure change. Results show that the average power generation of Lingnan Wind Farm was 44.4 MW/h during the study period, and when Typhoon Chaba approaches the wind farm within a proximity of less than 300 km, the average power generation increases by 43%. Conversely, when Chaba is more than 600 km away from the wind farm, the average power generation decreases by 10%. The analysis employing a random forest model identifies wind speed at 80 m height, 24-h pressure change, and pressure as the most influential factors throughout the study period. This underscores the significance of surface pressure and pressure variations at the wind farm for predicting wind power output at coastal wind farms during a typhoon process. The random forest model yields mean absolute error and root mean square error values of 9.4 MW/h and 11.6 MW/h, respectively, in the prediction of wind power generation.

This study investigates the micro-pore structure characteristics and genesis of low-resistivity reservoirs in the Wufeng and Longmaxi Formation of the Sichuan Basin. A comprehensive analytical approach—combining core analysis, gas adsorption, high-pressure mercury intrusion, and X-ray photoelectron spectroscopy (XPS) was employed to systematically characterize the pore structure of low-resistivity shale reservoirs and their relationship with electrical resistivity. The results reveal that low-resistivity shale reservoirs typically exhibit smaller pore volume and specific surface area, along with a higher degree of organic matter graphitization. This organic matter graphitization process significantly reduces the rock's resistivity. Pore structure evolution is governed by both compaction and tectonic deformation, leading to macropore reduction and meso-/micropore redistribution. Morphological transformations in organic matter pores—including pore collapse and wall contact—further facilitate electron migration and contribute to resistivity decline. By analyzing microstructural features of the Wufeng–Longmaxi shale, this study highlights the dominant influence of organic matter maturity, graphitization, and pore structure dynamics on resistivity, offering a theoretical framework for understanding the genesis and guiding exploration of low-resistivity shale gas reservoirs.

Gas turbine exhaust temperatures typically exceed 500°C, with waste heat recovery significantly improving thermal efficiency. As a mainstream recovery technology, the organic rankine cycle (ORC) utilizes cyclopentane working fluid that has high evaporation temperatures but carries flammability risks. The combined dry and flooded heat exchangers stabilize flow while ensuring superheat, requiring strict liquid level safety. This study investigates dynamic characteristics and control strategies of a flooded ORC system with cyclopentane. Within safe liquid level ranges, pump speed affects system power by merely 0.48% maximum, eliminating the need for regulation; cooling water flow control yields no benefits, while an optimal 0.1 split ratio exists in heat transfer oil. The system maintains safe levels through pump speed adjustment according to operating condition variations and maximizes output power via heat transfer oil split ratio modulation. This study provides theoretical foundations for the operation and control of cyclopentane and flooded ORC systems.

This paper presents an adaptive population size (NP)–based accelerated Particle Swarm Optimization (AAPSO) algorithm for duty cycle–based maximum power point tracking (MPPT) in photovoltaic (PV) systems. The proposed method directly modulates the duty cycle of a DC–DC converter, enabling rapid and precise adjustments to the maximum power point (MPP) under both uniform and partial shading conditions. AAPSO enhances conventional PSO by adopting a social-only variant and an adaptive Population size (NP) mechanism that begins with a large population for exploration and gradually reduces it to balance exploration and exploitation. To ensure robustness, the algorithm is executed 100 times, and performance is analyzed using statistical metrics and run-length distribution (RLD). Simulation results demonstrate approximately 99.8% tracking efficiency with a 100% tracking accuracy across all runs, while convergence counts are reduced nearly threefold compared to conventional Particle Swarm Optimization (CPSO) and two recent adaptive PSO-based MPPT methods from the literature. Experimental validation using a Ćuk converter prototype further confirms its practical feasibility. Overall, this study contributes an adaptive, duty cycle–based constrained PSO framework that integrates robustness, scalability, and statistical reliability for MPPT in large-scale PV systems.

In petroleum recovery processes, crude oil emulsions serve a crucial yet complex dual role. While facilitating hydrocarbon transport from subterranean reservoirs to surface facilities, excessively stable emulsions create significant challenges in downstream dehydration operations. The heightened stability of these colloidal systems necessitates increased demulsifier dosages and elevated separation temperatures, thereby substantially escalating operational expenditures. This technological dichotomy underscores the critical need for a comprehensive understanding of emulsion formation mechanisms, comparative evaluation of demulsification methodologies, and fundamental insights into destabilization processes—all essential for optimizing field operations. Building upon systematic analysis of emulsion characteristics and stabilization mechanisms, this study presents a critical synthesis of contemporary physical and chemical demulsification technologies. We conduct a comparative assessment of their technical advantages and operational limitations, with particular emphasis on advancing chemical demulsification strategies. The paper provides a rigorous classification and mechanistic analysis of diverse demulsifier categories, elucidating their interfacial activity and molecular-level interactions at oil–water interfaces. Looking toward future developments, we propose promising directions for next-generation demulsifier design and emerging hybrid separation technologies. These forward-looking perspectives aim to inform the development of cost-effective dehydration solutions while addressing current technological gaps in heavy crude processing and environmentally sustainable demulsification.

In this paper, the research on casing running is analyzed. By analyzing the stress and deformation of casing string with centralizer, the calculation model of friction, bending and centralizer pointing force in the process of horizontal down-hole running of casing string is derived, and the friction between casing and running hole wall is solved by iterative method. The mathematical model is used to entangle the bending force of casing. When the string is bent along the bending direction of borehole trajectory, the bending force is related to the casing outer diameter, cross-sectional area and string length. Then, the influence of casing additional force, such as drilling fluid viscous resistance, keyway rock breaking resistance, casing buckling additional load, casing running dynamic load and rotating casing running, on casing friction is analyzed in detail. The dynamic load of running casing makes the casing in curved and vertical sections bear large alternating load of tension and pressure, and rotating casing running may be an effective measure to reduce the friction of running casing. To run casing safely in extended reach horizontal well, the floating casing technology was simulated and analyzed. The safety of the horizontal well casing has been compromised, providing a casing cement sheath safety guarantee for future CO₂ injection production measures in oil and gas wells.