Three-dimensional analysis of a plate methanol steam micro-reformer and a methanol catalytic combustor with different flow channel designs

Hsueh, Ching-Yi; Chu, Hsin-Sen; Yan, Wei‐Mon; Leu, Guang-Ching; Tsai, Jong-Ian

doi:10.1016/j.ijhydene.2011.07.099

Cited by 48 publications

(13 citation statements)

References 31 publications

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“…This scheme has been supported and experimentally validated by different researchers [81][82][83][84][85][86][87]. The three parallel reactions are shown in Equations (1)-(3).…”

Section: Reaction Mechanism Of Methanol Steam Reformingmentioning

confidence: 75%

Review on Copper and Palladium Based Catalysts for Methanol Steam Reforming to Produce Hydrogen

Shuai

2017

Catalysts

108

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Abstract:Methanol steam reforming is a promising technology for producing hydrogen for onboard fuel cell applications. The methanol conversion rate and the contents of hydrogen, carbon monoxide and carbon dioxide in the reformate, significantly depend on the reforming catalyst. Copper-based catalysts and palladium-based catalysts can effectively convert methanol into hydrogen and carbon dioxide. Copper and palladium-based catalysts with different formulations and compositions have been thoroughly investigated in the literature. This work summarized the development of the two groups of catalysts for methanol steam reforming. Interactions between the activity components and the supports as well as the effects of different promoters were discussed. Compositional and morphological characteristics, along with the methanol steam reforming performances of different Cu/ZnO and Pd/ZnO catalysts promoted by Al 2 O 3 , CeO 2 , ZrO 2 or other metal oxides, were reviewed and compared. Moreover, the reaction mechanism of methanol steam reforming over the copper based and palladium based catalysts were discussed.

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“…This scheme has been supported and experimentally validated by different researchers [81][82][83][84][85][86][87]. The three parallel reactions are shown in Equations (1)-(3).…”

Section: Reaction Mechanism Of Methanol Steam Reformingmentioning

confidence: 75%

Review on Copper and Palladium Based Catalysts for Methanol Steam Reforming to Produce Hydrogen

Shuai

2017

Catalysts

108

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“…Compared to other designs, single channel designs show even flow distributions and higher flow velocities, which reduces the stagnant film adjacent to the channel walls and improves the heat-transfer rates [13][14][15][16]. High reaction rates are also observed in this designs which lead higher conversions.…”

Section: Single Channel Reformersmentioning

confidence: 87%

“…The performance of single channel reactors lays between plug flow and laminar reactors [12]. This type of design improves significantly the mixing, reaction and heat-transfer rates [13][14][15].…”

Section: Single Channel Reformersmentioning

confidence: 99%

Study of different designs of methanol steam reformers: Experiment and modeling

Ribeirinha

Boaventura

Lopes

et al. 2014

International Journal of Hydrogen Energy

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Three reformers with different designs (multi-channel, radial and tubular) were developed for thermal integration with a high temperature polymeric electrolyte membrane fuel cell (HT-PEMFC). They were characterized experimentally at temperatures between 443 K and 473 K, using the commercial catalyst G66 MR from Süd-Chemie (CuO/ZnO/Al2O3). The reactors were modelled and simulated using a computational fluid dynamics (CFD) analysis. The models were validated using experimental data.The results showed that the multi-channel design is the best solution for thermal integration with a HT-PEMFC, presenting high methanol conversion and low pressure drop. Regarding the heat transfer ability, the multi-channel showed also the best performance, presenting the lowest temperature sink among the studied reformers. The low flow velocities and the absence of metallic surfaces in the radial reformer had detrimental effect on the heat transfer. Concerning the flow distribution a coefficient of variation of 0.6 % was observed in the multichannel reformer. A quasi plug flow behavior was found in the tubular and a multichannel (channels region only) reformer, while in the radial a not fully developed laminar flow was found.At temperatures lower than 473 K was found that the reformate stream did not require further purification to be fed to a HT-PEMFC due to the low CO concentration (<1600 ppm).The advantages and limitations of each design is discussed based on experimental data and CFD modeling.

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“…Until recently, most of the numerical and experimental investigations have focused on the steady-state performance of catalytic micro-combustors and micro-reformers (Fanaee and Esfahani, 2014;Hsueh et al, 2011;Leu et al, 2013;Sari and Zohrabian, 2014). On the other hand, a limited number of investigates investigated the transient response and particularly the light-off (ignition process).…”

Section: Frontiers In Heat and Mass Transfermentioning

confidence: 99%

Effect of Wall Thermal Conductivity on Hydrogen-Assisted Catalytic Ignition Characteristics of Propane-Air at Micro-Scales in Different Feeding Modes

Chen¹,

Gao²,

Xu³

2015

Frontiers in Heat and Mass Transfer

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Effect of wall thermal conductivity on hydrogen self-ignition and hydrogen-assisted ignition of propane-air mixtures in different feeding modes from ambient cold-start conditions were investigated numerically with chemical kinetic model in Pt/γ-Al2O3 catalytic micro-combustors. For the steady and transient state, effect of wall thermal conductivity on self-ignition characteristics of lean hydrogen-air mixtures was presented, and hydrogenassisted combustion of propane-air mixtures was investigated numerically in the co-feed mode and the sequential feed mode. The computational results indicate the large thermal inertia of the micro-combustor solid structure leads to slow temperature dynamics, and transient response is dominated by the thermal inertia. The heat localization in poorly conducting walls leads to fast ignition and shorter steady state time. In general, the concentration of hydrogen required for propane ignition increased with increasing wall thermal conductivity, decreasing inlet velocity, and decreasing inlet equivalence ratio of propane-air mixtures. In the co-feed mode, the combustion characteristics of hydrogen-assisted propane qualitatively resemble the selectively preheating initial portion of the combustion chamber wall. In the sequential feed mode, the time taken to reach steady state, the hydrogen cut-off time, the propane ignition time and the cumulative propane emissions increased with increasing wall thermal conductivity; the ignition characteristics are similar to partially preheating the initial segment for low and moderate wall thermal conductivity values (0.5 and 20 W/m· K); however, the ignition characteristics are close to completely heating the micro-combustor wall for high wall thermal conductivity values (200 W/m· K).

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Three-dimensional analysis of a plate methanol steam micro-reformer and a methanol catalytic combustor with different flow channel designs

Cited by 48 publications

References 31 publications

Review on Copper and Palladium Based Catalysts for Methanol Steam Reforming to Produce Hydrogen

Review on Copper and Palladium Based Catalysts for Methanol Steam Reforming to Produce Hydrogen

Study of different designs of methanol steam reformers: Experiment and modeling

Effect of Wall Thermal Conductivity on Hydrogen-Assisted Catalytic Ignition Characteristics of Propane-Air at Micro-Scales in Different Feeding Modes

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