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The present study focuses on synthesizing a high‐temperature stable membrane working under low relative humidity (RH) by aminating the traditional polyethersulfone polymer with aniline for fuel cell applications. A condensed‐phase optimized molecular potentials for atomistic simulation studies force field‐based molecular dynamics simulation was used to explore the microscopic properties and transport of water and hydronium (H3O+) ions across the electrolyte at varied temperatures and RHs. COMSOL calculates oxygen and hydrogen concentrations after examining the polymer–ion interaction with the radial distribution function (RDF). The high H3O+ diffusion coefficient of the aniline‐treated membrane shows the benefit of the modification. The RDF confirmed the high interaction of the amine group with H3O+ and water. The high proton conductivity of 0.18 Scm−1 at 150°C with 33% RH for the aniline‐treated membrane was obtained, which was further investigated in COMSOL software to determine the hydrogen and oxygen concentration at the anode and cathode sides, respectively. Both electrodes' water transportation profiles were simulated numerically. The aniline‐treated membrane's good findings suggest high‐temperature proton exchange fuel cell membrane potential. [ABSTRACT FROM AUTHOR]

Hydrodynamics characterization in terms of flow regime behavior is a crucial task to enhance the design of bubble column reactors and scaling up related methodologies. This review presents recent studies on the typical flow regimes established in bubble columns. Some effort is also provided to introduce relevant definitions pertaining to this field, namely, that of "void fraction" and related (local, chordal, cross-sectional and volumetric) variants. Experimental studies involving different parameters that affect design and operating conditions are also discussed in detail. In the second part of the review, the attention is shifted to cases with internals of various types (perforated plates, baffles, vibrating helical springs, mixers, and heat exchanger tubes) immersed in the bubble columns. It is shown that the presence of these elements has a limited influence on the global column hydrodynamics. However, they can make the homogeneous flow regime more stable in terms of transition gas velocity and transition holdup value. The last section is used to highlight gaps which have not been filled yet and future directions of investigation. [ABSTRACT FROM AUTHOR]

Bubble and slurry bubble column reactors (BCRs/SBCRs) are used for various chemical, biochemical, and petrochemical applications. They have several operational and maintenance advantages, including excellent heat and mass transfer rates, simplicity, and low operating and maintenance cost. Typically, a catalyst is present in addition to biochemical processes where microorganisms are used to produce industrially valuable bio-products. Since most applications involve complicated gas-liquid, gas-liquid-solid, and exothermic processes, the BCR/SBCR must be equipped with heat-exchanging tubes to dissipate heat and control the reactor's overall performance. In this review, past and very recent experimental and numerical investigations on such systems are critically discussed. Furthermore, gaps to be filled and critical aspects still requiring investigation are identified. [ABSTRACT FROM AUTHOR]