Chemical Engineering & Technology最新文献

The present study investigates the steady incompressible natural convective flow of power law fluid in a squared enclosure having a T-shaped fin under the magnetic field and thermal radiation effects. The governing partial differential equations (PDEs) are transformed into nondimensional equations by employing dimensionless variables. The resulting system of dimensionless PDEs is solved numerically. The numerical simulations showed that the velocity and temperature profiles increases at higher Rayleigh number. Further, the addition of a magnetic field, quantified by the Hartmann number, decreases the fluid velocity and kinetic energy, reflecting the resistive effects of magnetic forces on the flow dynamics. The local and average Nusselt numbers decreases for higher radiation parameter. The obtained outcomes provide valuable insights for applications used in advanced thermal management systems, requiring fluid flow control and enhancing heat transfer.

Microfluidic dual Y-junction channels play a vital role in biomedical, chemical, and industrial applications. Yet studies on non-Newtonian fluid behavior in such complex geometries remain limited. The current study presents a computational fluid dynamics (CFD)-based analysis of Newtonian, shear-thinning (n = 0.00035), and shear-thickening (n = 1.23) fluids through a dual Y-junction channel, using COMSOL Multiphysics 6.0. A five-rectangle dual Y-channel was modeled to study velocity and pressure distributions using different types of fluid, as mentioned above. Results show Newtonian fluids exhibit linear pressure drops and smooth velocity profiles, whereas shear-thinning fluids display symmetric velocity peaks and nonlinear pressure variations. On the other hand, shear-thickening fluids demonstrate multimodal velocity with complex pressure recovery patterns. These insights aid in optimizing microfluidic designs for applications such as polymer processing, lab-on-chip systems, and biological fluid transport.

This review provides recent findings about the membranes fabricated using green solvents concerning their pore sizes and structure. We summarized preparations of green membranes and solvent recovery after membrane fabrication using polymer membranes. Recent studies on machine learning (ML), offering new efficient routes for membrane preparation were discussed. Regardless of the type of solvent, the most important parameters that control porosity of the membranes are thermodynamic and kinetic parameters. The field of solvent recovery with the aid of ML will evolve in the next decade and help to fully satisfy the principles of green chemistry and minimization of environmental pollution.

This study presents the synthesis of a multifunctional polymer nanocomposite (hereinafter, chitosan-4-hydroxybenzaldehyde/CuO [CHI-4HBA/CuO]) based on 4-hydroxybenzaldehyde (4HBA)-modified chitosan Schiff base and CuO nanoparticles. The CHI-4HBA/CuO nanocomposite was characterized using field emission scanning electron microscopy with energy-dispersive x-ray spectroscopy (FESEM–EDX), Brunauer–Emmett–Teller (BET) surface area analysis, differential scanning calorimetry–thermogravimetric analysis (DSC–TGA), x-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FTIR). The adsorption properties of CHI-4HBA/CuO were investigated through the removal of organic dye (eosin Y, EOY). Box–Behnken design (BBD) was used to optimize the adsorption of EOY. The CHI-4HBA/CuO demonstrated a BET surface area of 24.43 m²/g and a total pore volume of 0.02135 cm³/g. The optimal adsorption conditions (0.075 g dose, pH ∼ 4, 39 min) yielded 91.43% EOY removal efficiency. The CHI-4HBA/CuO demonstrated an adsorption capacity of 250.43 mg/g.

Pipeline corrosion is a major cause of leakage in the oil and gas industry, posing serious safety and environmental risks. This study proposes an accelerated evaluation strategy integrated with predictive modeling to enable rapid and accurate estimation of pipeline corrosion rates. Steel pipelines were subjected to hydrochloric acid (0.1–1.0%) immersion tests at 10–35°C, and data obtained under strong acidic conditions were used to establish correlations applicable to milder environments. Based on these datasets, a multi-parameter coupled model was developed in MATLAB with pH and temperature as core inputs. Validation against experiments confirmed high reliability, with prediction errors consistently below 10%. The model is linked to the refinery's DCS and HAZOP framework, enabling real-time monitoring and early warning for a wax oil hydrogenation unit, providing a practical tool for corrosion assessment, risk reduction, and safer pipeline operation.

This study investigates Williamson nanofluid slip flow along a permeable melting nonlinear stretch sheet with activation energy, inclined magnetic field, heat source/sink, thermo-solutal buoyancy forces, and thermophoretic velocity. Partial differential equations (PDEs) governing the physical phenomena are formulated and converted to nonlinear ordinary differential equations (ODEs) through similarity transformations. We applied the Runge–Kutta–Fehlberg fourth-fifth order method (RKF45) for numerical solutions of ODEs. The key outcomes obtained indicate that the velocity profile decreases with a higher velocity slip parameter and angle of inclination, while it increases with the melting parameter. The temperature distribution declines with increasing endothermic/exothermic reaction parameter, activation energy parameter, and melting parameter, while the concentration field increases with the activation energy parameter and melting parameter.

This study presents a multiphase transfer–reaction model integrating reaction kinetics, hydrodynamics, and gas–liquid mass transfer to simulate sodium sulfide's non-catalytic (WAO) and catalytic (CWAO) wet air oxidation in bubble column reactors. Developed to optimize reactor parameters under 373–423 K and 3.28 MPa, the model addresses high chemical oxygen demand (COD) in petrochemical spent caustic. For WAO, a 1.6 m-diameter, 12.5 m-high reactor with 0.04 m/s superficial gas velocity achieves 95% COD degradation at 423 K. FeSO₄-catalyzed CWAO reduces reactor size, shortens residence time (same efficiency), and boosts oxygen utilization. Compared with computational fluid dynamic (CFD)-reaction coupling, this empirical model cuts computational cost while retaining accuracy, fitting industrial scale-up. This study provides a sustainable framework for the design of spent caustic oxidation reactors, balancing environmental compliance with process efficiency.

Multifeature (MF) design is a potential approach for the secondary design of microchannel heat sinks (MHSs). In this paper, turning microchannels with variable cross sections (TM-VC) were designed. The effects of different coupling methods on the convective heat transfer performance were studied. The results revealed that MF designs can effectively enhance heat transfer performance. Under the same pumping power consumption, compared with that of single-feature microchannels and traditional straight microchannels, the heat transfer performance of turning microchannels with inner ribs and outer cavities (TM-OCIR) increased the most—up to 19.3% and 35%, respectively. The local entransy theory was also employed to analyze and elucidate the heat transfer mechanism of the TM-VC. The results showed that the turning effect can enhance the inner rib effect, leading to lower entransy dissipation and higher entransy gain (EG), thus achieving higher convective heat transfer efficiency.

Carica papaya leaves are renowned as a traditional remedy to treat dengue fever, with carpaine identified as the principal alkaloid. This study evaluated the effects of solvent type, duration, and technique on carpaine yield, phenolic recovery, and antioxidant capacity from papaya leaves. Extractions were performed with ethanol or water at different durations (3–30 min) for soaking with agitation (SA), ultrasound-assisted (UE), and microwave-assisted extraction (ME). ME with ethanol (15 min) extracted the highest amount of carpaine, whereas ME with water (7 min) provided the highest extraction yield, phenolic contents, and antioxidant capacities. Computer simulation confirmed ethanol as a more favorable medium for carpaine extraction due to enhanced heat and mass transfer. Overall, ME demonstrated superior efficiency for both carpaine and phenolic recovery at shorter durations, underscoring its potential for scalable production of bioactive extracts from papaya leaves.