A comprehensive review of PBI-based high temperature PEM fuel cells

Energy efficiency improvements by investigating the water flooding management on proton exchange membrane fuel cell (PEMFC)

Hierarchical zeolites combine the intrinsic catalytic properties of microporous zeolites and the enhanced access and transport of the additional meso- and/or macroporous system. These materials are the most desirable catalysts and sorbents for industry and become a highly evolving field of important current interests. In addition to the enhanced mass transfer leading to high activity, selectivity, and cycle time, another essential merit of the hierarchical structure in zeolite materials is that it can significantly improve the utilization effectiveness of zeolite materials resulting in the minimum energy, time, and raw materials consumption. Substantial progress has been made in the synthesis, characterization, and application of hierarchical zeolites. Herein, we provide an overview of recent achievements in the field, highlighting the significant progress in the past decade on the development of novel and remarkable strategies to create an additional pore system in zeolites. The most innovative synthesis approaches are reviewed according to the principle, versatility, effectiveness, and degree of reality while establishing a firm link between the preparation route and the resultant hierarchical pore quality in zeolites. Zeolites with different hierarchically porous structures, i.e., micro-mesoporous structure, micro-macroporous structure, and micro-meso-macroporous structure, are then analyzed in detail with concrete examples to illustrate their benefits and their fabrications. The significantly improved performances in catalytic, environmental, and biological applications resulting from enhanced mass transport properties are discussed through a series of representative cases. In the concluding part, we envision the emergence of "material-properties-by-quantitative and real rational design" based on the "generalized Murray's Law" that enables the predictable and controlled productions of bioinspired hierarchically structured zeolites. This Review is expected to attract important interests from catalysis, separation, environment, advanced materials, and chemical engineering fields as well as biomedicine for artificial organ and drug delivery systems.

Hierarchically Structured Zeolites: From Design to Application.

Depleting energy resources have become the driving force for their conservation. Increasing the system efficiencies is one method by which sustainability of energy may be ensured, for which miniaturization has successfully provided solutions. Miniature heat exchangers, owing to their high thermal performance, have the potential to provide energy efficient systems. In addition, their characteristics of compactness, small size and lesser weight have attracted widespread applications. Various works on micro- and minichannel heat exchangers as heat sinks and heat exchangers have been reviewed in this paper. Currently employed fabrication techniques and different applications have been summarized. An overview of the single-phase thermo-hydraulic studies in micro- and minichannel heat sinks has been presented. Literatures related co-current, counter-current and cross-current micro- and minichannel heat exchangers have been discussed. Finally, the persisting lacunae of this technology drawn from the review have been pointed out.

Review of micro- and mini-channel heat sinks and heat exchangers for single phase fluids

Electronics cooling with nanofluids: A critical review

CFD study of liquid-cooled heat sinks with microchannel flow field configurations for electronics, fuel cells, and concentrated solar cells

Cfd study on flow distribution uniformity in fuel distributors having multiple structural bifurcations of flow channels

Jet fuels are strategic fuels widely used in airplanes. Through appropriate reforming and shifting processing, jet fuels can be converted into syngas, which is a suitable fuel to solid oxide fuel cells for many auxiliary and backup power units. Integrated micro fuel processors in combination with solid oxide fuel cell (SOFC) stacks using jet fuels have been viewed as attractive portable power sources. Because the sulfur in jet fuels easily causes catalyst poisoning for fuel processing reactions and the electrochemical reactions in fuel cells, ultra-deep sulfur removal in jet fuels and many other hydrocarbon fuels has become a very important and active research subject worldwide in the last 15 years. Amongst the state-of-the-art technologies, selective adsorption for removing sulfur (SARS) is emerged to be very attractive. SARS has been regarded as the most promising approach because it obtains ultra-deep desulfurization efficiency at ambient temperature and atmospheric pressure without hydrogen consumption. In this paper, we survey the current status and prospect of the SARS technology for jet fuels, and will discuss some important issues remaining for the SARS technology in the future. The final goal of this survey is to find/innovate a promising method for jet fuel desulfurization, which is most suitable for supplying fuels to solid oxide fuel cell auxiliary and backup power units.

Selective adsorption for removing sulfur: a potential ultra-deep desulfurization approach of jet fuels

In this study, a significant number of experimental tests to PEM fuel cells were conducted to investigate the effect of gas flow fields on fuel cell performance. Graphite plates with various flow field or flow channel designs, from literature survey and also novel designs by the authors, were used for the PEM fuel cell assembly. The fabricated fuel cells all have an effective membrane area of 23.5 cm2. The results showed that the serpentine flow channel design is still favorable, giving the best single fuel cell performance amongst all the studied flow channel designs. A novel symmetric serpentine flow field was proposed for relatively large size fuel cell application. Four fuel cell stacks each including four cells were assembled using different designs of serpentine flow channels. The output power performances of fuel cell stacks were compared and the novel symmetric serpentine flow field design is recommended for its very good performance.

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Hong Liu

Papers

CFD study of liquid-cooled heat sinks with microchannel flow field configurations for electronics, fuel cells, and concentrated solar cells

Cfd study on flow distribution uniformity in fuel distributors having multiple structural bifurcations of flow channels

Selective adsorption for removing sulfur: a potential ultra-deep desulfurization approach of jet fuels

Experimental Study and Comparison of Various Designs of Gas Flow Fields to PEM Fuel Cells and Cell Stack Performance

Optimization of PEM fuel cell flow channel dimensions—Mathematic modeling analysis and experimental verification