Portable power production from methanol in an integrated thermoeletric/microreactor system

Karim, Ayman M.; Federici, J.A.; Vlachos, Dionisios G.

doi:10.1016/j.jpowsour.2007.12.119

Cited by 89 publications

(38 citation statements)

References 17 publications

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“…• C. These results are in agreement with similar studies that show higher fuel-air flow rate results in higher rate of heat release by the catalysis reaction manifested as an elevated stable temperature [15,25]. The diminishing rate of corresponding increase in temperature can be attributed to the saturation of the active catalytic sites leading to incomplete conversion of reactants to products.…”

Section: Flow Rate Dependencesupporting

confidence: 91%

“…In other words, the loss in Pt porosity and specific surface area, such as seen in Figure 5(c), demonstrated only minor influence on the reactivity of the catalyst for the conditions and materials tested. Catalyst stability similar to that observed here has been demonstrated before by Karim and coworkers [15] with Pt nanoparticles deposited on anodized alumina substrate. However, the higher operating stable temperatures with the repeatable cycling studies make these results unique and warrant further investigation of operational regimes for this system as required for potential applications in a portable power production device.…”

Section: Catalyst Materials Characterizationsupporting

confidence: 89%

“…The results obtained in this fundamental study will also potentially be used to enhance the performance and sustain chemical reaction in a microscale combustor. In the past 10 years, much research has been performed on microscale combustion aimed at developing a small-scale generator that can replace batteries and rapidly be recharged by simply adding fuel [4,[4][5][6][7][8][9][10][11][12][13][14][15][16][17]. Since hydrocarbon fuels have an energy density of ∼40 MJ/kg, a device having an overall systemlevel efficiency (chemical-to-electrical energy) in excess of 1% would have a comparable energy density to the stateof-the-art Li-ion batteries (∼0.5 MJ/kg) [18,19].…”

Section: Introductionmentioning

confidence: 99%

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Catalysis of Methanol‐Air Mixture Using Platinum Nanoparticles for Microscale Combustion

Applegate

Pearlman

Bakrania

2012

Journal of Nanomaterials

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High surface area, active catalysts containing dispersed catalytic platinum nanoparticles (d p ∼ 11.6 nm) on a cordierite substrate were fabricated and characterized using TEM, XRD, and SEM. The catalyst activity was evaluated for methanol oxidation. Experimental results were obtained in a miniature-scale continuous flow reactor. Subsequent studies on the effect of catalyst loading and reactor flow parameters are reported. Repeat tests were performed to assess the stability of the catalyst and the extent of deactivation, if any, that occurred due to restructuring and sintering of the particles. SEM characterization studies performed on the postreaction catalysts following repeat tests at reasonably high operating temperatures (∼500• C corresponding to ∼0.3T m for bulk platinum) showed evidence of sintering, yet the associated loss of surface area had minimal effect on the overall catalyst activity, as determined from bulk temperature measurements. The potential application of this work for improving catalytic devices including microscale reactors is also briefly discussed.

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Section: Flow Rate Dependencesupporting

confidence: 91%

Section: Catalyst Materials Characterizationsupporting

confidence: 89%

Section: Introductionmentioning

confidence: 99%

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Catalysis of Methanol‐Air Mixture Using Platinum Nanoparticles for Microscale Combustion

Applegate

Pearlman

Bakrania

2012

Journal of Nanomaterials

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“…Furthermore, ignition determines the time length required for start-up and the associated pollutant emissions during this period. The start-up of a propane-fueled, platinum-coated micro-combustor, with added hydrogen to facilitate light-off, has been demonstrated experimentally (Norton and Vlachos, 2005), while the self-ignition of methanol-air mixtures in similar micro-reactors coupled to thermo-electrical devices have been investigated (Karim et al, 2008). The former work mainly focused on developing a start-up strategy for the specific micro-combustor and micro-reactor, while the latter demonstrated the feasibility of integrating a self-igniting catalytic micro-combustor to a power generating system.…”

Section: Frontiers In Heat and Mass Transfermentioning

confidence: 99%

“…Applications range from catalytic micro-thrusters for space applications (Volchko et al, 2006), to micro-reactors used for fuel reforming in micro solid oxide fuel cells (Cheekatamarla et al, 2008), and to scaled-down thermal engines, wherein catalytic microcombustors are used for direct chemical-to-thermal energy conversion (Gomez et al, 2007;Karim et al, 2008). Noble metal catalysts (such as Pt, Pd, Rh, etc.)…”

Section: Introductionmentioning

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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Micro Process Technology and Novel Process Windows – Three Intensification Fields

Borukhova¹,

Hessel²

2013

Process Intensification for Green Chemistry

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Portable power production from methanol in an integrated thermoeletric/microreactor system

Cited by 89 publications

References 17 publications

Catalysis of Methanol‐Air Mixture Using Platinum Nanoparticles for Microscale Combustion

Catalysis of Methanol‐Air Mixture Using Platinum Nanoparticles for Microscale Combustion

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

Micro Process Technology and Novel Process Windows – Three Intensification Fields

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