AIChE Journal最新文献

As the primary proton-conducting carrier in high-temperature proton exchange membrane fuel cells (HT-PEMFCs), the leaching process of phosphoric acid (PA) substantially accelerates performance decay and reduces the lifespan of PEMFCs. A three-dimensional Lattice Boltzmann Method model is presented to simulate the PA leaching process in HT-PEMFCs by coupling the catalytic layer structures generated by the improved quartet structure generation set method. The model demonstrates high efficiency, accuracy, and realism. Based on this model, the process of PA droplets invading the catalytic layer is described in detail, and the influence of factors such as porosity on fluid dynamics is analyzed. The results indicate that in the catalytic layers with different porosities, ε = 54% is associated with reduced droplet invasion and an acceptable pressure increase; smaller droplets, lower gas velocity conditions, thicker catalytic layers, and larger contact angles have been shown to be more conducive to mitigating the impact of PA invasion.

Wet scrubbers are widely used to mitigate fossil fuel emissions, making improvements in their efficiency an impactful pursuit. In this study, we analyze an atypical approach to liquid distribution in wet scrubbers that uses liquid drops flowing down vertical fibers which offers several benefits. These include extended residence time, reduced pressure drop, monodisperse drop size distributions and tunability of all of these, including the drop number density. The residence time and drop number density are the most significant of the aforementioned effects and are strongly affected by viscosity. Accordingly, we chose to study silicone oils, available in a range of viscosities, to investigate the scavenging coefficient of fiber-guided drops, and demonstrate their potential to enhance wet scrubber performance. Additionally, we identify optimal system parameters for effectively capturing particles across a range of particle diameters, paving the way for more efficient wet scrubbers.

Photothermal-driven methanol/water reforming offers as a sustainable route for low-temperature, on-site hydrogen (H₂) production by coupling solar energy with liquid fuel compatibility. Herein, a HRGO/Cu₂O@CuMOF core-shell heterojunction catalyst was in situ constructed via a homologous coordination etching strategy. This design introduces dual-interface synergy and confined spatial architecture: HRGO-Cu⁺ interface enhances water adsorption and activation, accelerating OH· radical generation for C–H bond cleavage in methanol; Cu₂O-CuMOF junction facilitates charge separation and stepwise dehydrogenation through spatially confined intermediate transformation. Benefiting from this cooperative architecture, the catalyst achieves a high H₂ production rate of 77.2 mmol g_cat⁻¹ h⁻¹ at 210°C, nearly 8 times of thermal reforming, with activation energy significantly reduced by 29.6%. Notably, the catalyst can initiate H₂ generation as low as 100°C, and maintains excellent activity and integrity over 72 h. This work offers a scalable strategy for constructing MOF-based heterojunctions with confined interface synergy, advancing sustainable photothermal H₂ production.

This work pursues a generalized filtered reaction rate (FRR) model for reactive gas–solid flows via fine-grid two-fluid model (TFM) simulations. The power-law kinetic with various reaction orders (n) is considered. It is well known that the solid-catalyzed reaction rate is bounded by the kinetic regime (KR) and external mass transfer-controlled regime (EMTR). It is found that the FRR model maintains excellent predictive performance both for n > 1 in two different regimes and n < 1 in the KR. However, an underprediction is observed at n < 1 within the EMTR. Thus, a modified formula for the FRR model in the EMTR is proposed. Then a generalized FRR model is derived. The assessment for the model is performed via a priori analysis and a filtered TFM simulation. The priori analysis and filtered TFM simulations quantitatively demonstrate that the model exhibits robust predictive capability.

Concentrated suspensions of very high phase fractions (>10%) significantly complicate hydrodynamic characteristics in multiphase reactors. The inline image method proposed recently provides the possibility to peer into dense particle swarm dynamics, previously considered an impossible mission. In this work, the method was further developed to determine the particle-resolved flow field and comprehensive datasets of particles within a swarm. Transient swarm microstructure demonstrated two aggregation states, that is, doublets and multiplets, accompanied by frequent collisions and friction. Statistical analysis indicated the damping effect on slip velocity and net force induced by the particle swarm became significant as solid holdup reached 13.2%, which markedly enhanced particle suspension. Through correlation analysis of dynamic datasets and relevant mechanisms, the viscous effect and hindrance effect exerted by the particle swarm were quantitatively elucidated for the first time. Accordingly, a correlation was proposed to predict the swarm effect on axial slip velocity, and good agreement was demonstrated across wide concentration ranges.