Chemical Engineering & Technology最新文献

Styrene is a typical hydrophobic volatile organic compound (VOC) that poses potential risks to both the environment and human health, making its efficient removal of great significance. Adding surfactants is an effective method to enhance efficiency of biotrickling filter (BTF) in removing hydrophobic VOCs. This study conducted experiments with and without adding rhamnolipid (RL, concentration 150 mg/L) as a control to investigate its impact on BTF's performance in removing styrene. Results showed that during BTF's initiation phase, compared with BTF1, which required 9 days for the removal efficiency (RE) to reach 100%, BTF2 achieved 100% RE in only 6 days. After initiation, as the styrene concentration at the inlet increased and the empty bed residence time decreased, the RE of BTF2 was on average 5% higher than that of BTF1 during the same period. Ultimately, BTF2 achieved a maximum elimination capacity (EC) of 186.27 g/m³/h, whereas BTF1's maximum EC was 149.51 g/m³/h. Following a starvation period, BTF2 restarted within 32 h, whereas BTF1 required 44 h. Finally, microbial community analysis revealed that the genera Psedomonas, Gordonia, and Comamonadaceae played major roles in styrene removal, while BTF2 supplemented with RL exhibited a higher abundance of dominant populations. In conclusion, adding RL to the nutrient solution positively affected BTF's styrene removal performance. It serves as an effective method to enhance BTF's removal of hydrophobic VOCs.

During railway coal transportation, coal dust dispersion causes serious economic and environmental issues. To improve low-temperature performance, this study develops an antifreeze-type, high-efficiency dust suppressant. By utilizing the hydrogen bonding between glycerol (Gly) and water molecules, the connections between water molecules are weakened, thereby preventing freezing at low temperatures. Meanwhile, hydrogen bonding and physical cross-linking between the branched-chain-rich xanthan gum (XG) molecules and the long-chain polymer polyacrylamide (PAM) molecules cause the dust suppressant solution to form a gel-like film layer, which enhances the solidification efficiency and strength. The optimal formula is 0.2% XG, 45% Gly, 0.01% PAM, and 54.79% water. This dust suppressant solution exhibits good antifreeze and solidification properties, providing new insights for reducing transportation losses of railway coal transport and mitigating dust-related environmental pollution.

Based on the developed multi-cavity rotating charger, an investigation into the triboelectric charging of PA, PP, PU, and ABS particles was conducted. First, the force and motion models of the particles were established. A collision model of particles inside the charger has been established, and the effects of rotational speed, tilt angle, and inner cavity diameter on the triboelectric collision of particles have been explored. Second, the triboelectric charging experiments of polymers were carried out using the developed multi-cavity rotating charger. Single-factor and orthogonal experiments revealed that factors influencing on charge-to-mass difference as: tilt angle > inner cavity diameter > rotational speed. Finally, the optimal charging parameter combination for the four-component polymer particles was determined through experiments. The research on particle charging provides theoretical and experimental support for their subsequent electrostatic separation.

This work formulates an energy-saving strategy to reduce excessive energy consumption in quaternary-mixture separation from printing volatile organic compounds. First, A conventional extractive distillation (CED) scheme was designed to fully separate the mixture containing two azeotropic groups. Total annual cost (TAC) and total energy consumption (TEC) were employed as objective functions to optimize column parameters using response surface methodology. Subsequently, heat integration and heat pumps were applied to intensify the CED process, resulting in five energy-saving configurations. These configurations were evaluated based on TAC, TEC, CO₂ emissions, and thermodynamic efficiency (TE). The CHHED-2 scheme including both heat integration and heat pump is the most energy-efficient, cost-effective, and environmentally friendly option. As compared to the original CED process, TAC, TEC, CO₂ emission could be decreased by 19.03%, 26.62%, 33.90%, respectively, TE increasing by 8.1%.

A series of sulfonic acid-functionalized ionic liquids (ILs) bearing different counter anions was synthesized using imidazole (IM) or 1-methylimidazole (MIM) as the cation, functioning effectively as Brønsted acid catalysts. Synthesized ILs exhibit distinct characteristic properties, which offer advantages in various aspects. Microwave-assisted fructose dehydration was examined for a series of ILs in IPA (isopropyl alcohol), which has a low-boiling point (LBP) and is a reaction medium. Of the tested series of ILs, 1-methylimidazole-based IL having p-TsOH (p-toluene sulfonic acid) anion showed excellent performance for fructose dehydration as well as the characteristic “smart” property of solidification at room temperature, which contributed to the ease of separation. Additionally, an intensification study was conducted to investigate the impact of reaction parameters. Reactions under optimized conditions of 120°C in IPA as a reaction medium and 120 s reaction time yielded a maximum of 62% for HMF and 95% fructose conversion. The [Benz-SO₃H MIM]⁺[OTs]⁻ was successfully recycled and reused due to its “smart” properties, showing consistent performance in terms of yield and conversion across five recycle runs. The use of “smart” ILs for 5-hydroxymethylfurfural (5-HMF) synthesis facilitates easy product separation with higher yield. It provides an added advantage of ease of recycling and separation, thereby contributing to a reduction in the overall production cost at a larger scale.

The Carreau fluid behavior is observed in multiple practical applications and a few familiar processes, such as blood flow, sewage sludge, due to paints or varnishes, waxy crude oils, etc. Its wide range of applications motivates us to focus on the two-dimensional laminar Carreau flow past an inclined stretching cylinder in the current analysis, which is significant in biomedical engineering and industrial processes. Additionally, real fluids are sensitive to temperature, and hence their thermal conductivity fluctuates with the surrounding temperature. Therefore, to attain a more reliable result in the present study, the thermal conductivity of the fluid is assumed as a function of temperature, and the model is influenced by the oblique magnetic field that is applied to the system externally. The flow model is mathematically framed through partial differential equations. The finite difference technique is adopted to discretize the governing equations. The original nonlinear system of equations is linearized using a quasi-linearization scheme. The strong convergence criteria are implemented in the code to ensure the convergence of the computational results. The final outcomes are extracted using the Thomas algorithm. The flow characteristics are studied and interpreted physically under the influence of different emerging parameters. The friction factor and heat transfer rate are also computed with an engineering interest. At a high shear rate, the flow characteristics are found to be higher in Newtonian fluid than in non-Newtonian fluid. The fluid velocity and temperature are altered with the angle of oblique cylinder, and they are higher with a lower angle of inclination. The flow parameters that influence the streamlines and isotherms are illustrated and discussed. It is concluded from the computations that the higher angle of inclination of the cylinder reduces the frictional force due to the fluid flow and increases the heat transfer rate near the wall. Also, when the oblique angle of the magnetic field is enhanced, the skin-friction coefficient reduces, and the heat transfer rate increases in both the Newtonian and non-Newtonian fluid flows.

Optimized heat and mass transfer in spinning shear-thinning materials is important for cardiovascular dynamics. Shear-thinning fluids model blood rheology in arteries and veins under spinning motion. The physical and biological properties of Williamson fluids are analyzed between the two rotating disks. The governing equations include accelerated heat and mass transfer, Soret and Dufour effects, in nonlinear magnetized radiated shear-thinning flow between bounded surfaces. Results show that a magnetic field reduces axial flow speed by up to 25% while increasing pressure by about 18%, whereas unsteady motion increases flow speed by about 15%. Concentration and temperature gradients enhance heat and mass transfer rates by 10%–20%. Stretching of the disks reduces resistive forces at both surfaces, and higher unsteadiness leads to a 12%–15% decrease in heat and mass fluxes.

This study proposes an enhanced Improved Refined Rotation RetinaNet (iR³Det) to address overlapping crystal detection challenges in crystallization processes. By integrating multi-scale Retinex image enhancement for improved visibility and fast neural architecture search for object detection (NASFCOS)-Feature Pyramid Network (FPN) into the neck network for refined feature representation, the method reduces missed detections while resolving crystal overlaps. Validated on in situ images of β-l-glutamic acid (β-LGA) during seeded batch-cooling crystallization, iR³Det demonstrates superior accuracy in extracting morphological parameters from adherent crystals compared to original R³Det and traditional segmentation methods. The algorithm effectively balances detection precision for both isolated and overlapping crystals, enabling reliable crystal size distribution analysis critical for crystallization process monitoring and control. This approach provides a robust solution for real-time crystal morphology characterization in dynamic industrial crystallization environments.