Thermochemical processes utilizing biomass demonstrate promising prospects for the generation of syngas. In this work, a gasification process employing combination of an indigenous low-grade coal with two distinct biomass sources, namely rice husk (RH) and wood sawdust (WS), was explored. The gasification of the selected feedstock was performed using a double-staged multi-opposite burner (MOB) gasifier. A 3D computational fluid dynamics (CFD) model was employed to analyze the effect of kinetic and diffusion rates on the overall gasification performance of an entrained flow biomass gasifier. DPM was employed to track the particles’ trajectory, while the gas phase was treated as the continuous phase, and its behavior was predicted using a standard k-epsilon turbulent model. To calculate both the homogeneous and heterogeneous reaction rates, the finite rate/eddy dissipation model was implemented. The findings indicate that the char conversion efficiency exceeded 95% across all instances. Among the different reaction schemes, scheme E (which involved complete volatile and char combustion reactions) produced better results in comparison with published results, with less than 1% error. Hence, scheme E was validated and utilized for the rest of the simulated cases. The feeding rate has an inverse effect on the overall performance of the gasifier. An increase in feed rate decreases the CO and H2 composition in syngas. The maximum CO value was observed to be 57.59% at a 1.0 O/C ratio with a 0.005 kg/s feed rate, and the maximum H2 value was observed to be 16.58% in the same conditions for Lakhra coal samples. In summary, Lakhra coal exhibited better performance than other biomass samples due to its better fixed carbon and volatiles in its composition.
10 September 2025 in Case Studies in Thermal Engineering
The titanium dioxide nanoparticles (TiO2NPs) were synthesized and functionalized with bovine serum albumin (BSA) to yield TiO2@BSA nanocomposites for targeted drug delivery. The chemotherapeutic drug vinorelbine (VRL), used for non-small cell lung and breast cancer, was loaded into the nanocomposites by a cost-efficient sol-gel method. The UV-vis spectrum exhibited an absorption peak at 361 nm, confirming the formation of TiO2 NPs. In the FTIR spectrum, the grafting of BSA was indicated by specific band shifts. XRD and FESEM revealed well-dispersed spherical particles with an average crystallite size of ⁓20 nm, and EDX confirmed elemental composition. The zeta potential of −29 mV indicated colloidal stability with a drug loading efficiency of 62%. In vitro release studies demonstrated pH-responsive behavior, with 98% cumulative release at an acidic pH (5.5) compared to 20% at physiological pH (7.4), indicating the suitability of this formulation for tumor-targeted delivery. Higuchi and Korsmeyer-Peppas models were used for the kinetics study, indicating that the mechanism was controlled by diffusion and swelling. Cytotoxicity evaluation via MTT assay showed enhanced uptake and anticancer activity of VRL-loaded TiO2@BSANPs against MCF-7 cells compared with free VRL. These results suggest TiO2@BSA nanocarriers as efficient, stable, and selective platforms for cancer therapy.
Computational fluid dynamics (CFD) was used to investigate influence of different gas sparger configurations and the presence of horizontal baffles on hydrodynamic characteristics in a flat bubble column. CFD results of time-averaged local and global gas holdup, liquid axial velocity, and Sauter mean diameter were experimentally validated. Subsequently, the validated CFD model was extended to investigate the effects of different gas sparger configurations, i.e., S1, S3, S4, S5, S8, and S72, and baffles arrangements, i.e., Config-A and Config-B on overall hydrodynamics at different superficial gas velocities (Ug = 0.0014 m/s and 0.0073 m/s). CFD results demonstrated significant influence of both sparger and Ug. Gas holdup and interfacial area increased with smaller, more numerous sparger openings, such that S72 achieved ~1.55 times higher holdup and ~2 higher interfacial area than that of S1. Spargers with fewer and larger openings induced stronger turbulence, which intensified early breakup and coalescence and broadened the bubble size distribution. Results revealed that spargers with many small openings (S72) produced the narrowest distribution, retaining a high fraction of bubbles of initial size (5 mm), whereas spargers with fewer larger openings (S1) generated broader distributions with significant coalescence, especially at higher Ug. The inclusion of baffles enhanced liquid circulation and gas–liquid mixing and contact. However, intensified turbulence below each baffle significantly increased coalescence, producing larger bubbles and resulting in only marginal changes in interfacial area despite increased gas holdup.