Micro-tubular flame-assisted fuel cells for micro-combined heat and power systems

Milcarek, Ryan J.; Wang, Kang; Falkenstein‐Smith, Ryan; Ahn, Jeongmin

doi:10.1016/j.jpowsour.2015.12.018

Cited by 49 publications

(26 citation statements)

References 25 publications

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“…Fuel utilization of the syngas as high as 34% at an operating voltage of 0.5 V has been reported in this setup when using methane fuel (Milcarek et al, 2016c). A peak power density of 430 mW.cm -2 has also been achieved with methane fuel, which is comparable to the power densities achieved with hydrogen fuel in many commercial systems (Milcarek et al, 2016d). The FFC maintains another advantage of the DFFC which is high fuel flexibility as many different solid, liquid and gaseous fuels can be used to generate electrochemical power (Horiuchi et al 2004).…”

Section: Introductionsupporting

confidence: 53%

“…A recent innovation on the DFFC design is to continue to utilize the flame for reforming of hydrocarbons to syngas and as a thermal energy source for the SOFC, while also utilizing a dual chamber configuration with sealing only on one end of a micro-tubular SOFC (mT-SOFC) (Milcarek et al, 2016a;Milcarek et al, 2016b;Milcarek et al, 2016c;Milcarek et al, 2016d). This DFFC operating in a dual chamber configuration has been termed a Flame-assisted Fuel Cell (FFC).…”

Section: Introductionmentioning

confidence: 99%

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Micro-tubular flame-assisted fuel cells

Milcarek

Garrett

Ahn

2017

JFST

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Micro-tubular solid oxide fuel cells operating in fuel-rich combustion exhaust are explored in this work and their benefits in reducing the balance of plant in fuel cell systems is discussed. The current state of performance of these micro-tubular flame-assisted fuel cells operating with methane fuel is described and the benefits of operating in propane fuel are explored. An experimental investigation of propane combustion at different fuel/air equivalence ratios is conducted. Temperature measurements of the propane combustion are recorded with thermocouples while the gas species present in the exhaust are measured with a gas chromatograph. Propane is found to have advantages over methane due to a higher upper flammability limit and higher percentages of hydrogen and carbon monoxide, i.e. syngas, generated in the combustion exhaust. A micro-tubular flame-assisted fuel cell is tested using the four probe technique in model propane combustion exhaust at different equivalence ratios and temperatures. A method for comparing the performance of the fuel cell in the combustion exhaust to a hydrogen fuel baseline is developed and comparisons are made. The benefits of operating in propane compared to methane are explored with the potential for fuels like propane and butane being distinguished by their higher upper flammability limits and potential for higher concentrations of syngas in the combustion exhaust.

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Section: Introductionsupporting

confidence: 53%

Section: Introductionmentioning

confidence: 99%

Micro-tubular flame-assisted fuel cells

Milcarek

Garrett

Ahn

2017

JFST

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“…The fuel-rich exhaust is then fed through a mT-SOFC where the remaining fuel is electrochemically converted to water and carbon dioxide. This concept was proposed recently operating in a furnace exhaust [36]. To gain a comprehensive understanding of the potential of this energy conversion concept, the fuel cells performance at different equivalence ratios and temperatures needs to be assessed.…”

Section: Introductionmentioning

confidence: 99%

Micro-tubular flame-assisted fuel cells running methane

Milcarek

Garrett

Wang

et al. 2016

International Journal of Hydrogen Energy

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Direct flame fuel cells (DFFCs) have been investigated as an alternative means of combustion based power generation devices, but current challenges for this technology have included low fuel utilization and efficiency. In order to overcome these obstacles a new micro-tubular flame-assisted fuel cell (mT-FFC) concept is developed in this work and its performance is assessed at different equivalence ratios and temperatures. The concept is based on fuel-rich combustion exhaust, with the combustion equivalence ratio controlled and the exhaust flowing through the fuel cell for complete electrochemical energy conversion. The results were compared to a hydrogen baseline with the same electron potential as the fuel-rich exhaust. The mT-FFC concept offers significant advantages including high fuel utilization and greater performance stability compared to DFFCs.

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“…In addition, the direct internal reformation of CH 4 reached equilibrium with/without electrochemical reactions since the mole fraction of CH 4 changed little at the low-temperature region. The temperature increase caused by the electrochemical reactions promoted the forward movement of chemical equilibrium of the direct internal reformation reaction of CH 4 , which promoted the conversion of CH 4 to H 2 and CO, and led to a decrease of the mole fraction of CH 4 . The mole fraction of H 2 O increased at the high-temperature region due to the electrochemical reaction of H 2 .…”

Section: Resultsmentioning

confidence: 99%

“…Meanwhile, it also provides heat for the SOFC to start up and operate. [2][3][4] FFCs have emerged as an attractive system owing to its simple setup and rapid startup. Until now, FFCs were investigated using various combustion concepts and different SOFC configurations.…”

mentioning

confidence: 99%

Mathematical Modeling of a Porous Media Burner Based Methane Flame Fuel Cell

Wang¹,

Zeng²,

Shi³

et al. 2017

J. Electrochem. Soc.

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A detailed two-dimensional axisymmetric computational model of a flame fuel cell (FFC) unit was developed and presented. The FFC unit is based on the integration of a fuel-rich methane flame in a porous media burner and a micro-tubular solid oxide fuel cell (SOFC). The model considered the coupling effects of the chemical reactions and electrochemical reactions and the heat-transport, masstransport and charge -transport processes in the FFC. The simulated temperature distribution and electrochemical characteristics showed good agreement with experimental data. The coupling mechanism of the fuel-rich flame and the SOFC anode were clarified. The Ni catalyst in the anode and the electrochemical reactions promoted the conversion of CH 4 in porous media fuel-rich combustion. A flame fuel cell (FFC) is a novel kind of solid oxide fuel cell (SOFC) in which a fuel-rich flame is directly integrated with an SOFC. 1 The fuel-rich flame acts as a partial oxidation reformer for the SOFC at the anode to convert C x H y to CO and H 2 . Meanwhile, it also provides heat for the SOFC to start up and operate. [2][3][4] FFCs have emerged as an attractive system owing to its simple setup and rapid startup. Until now, FFCs were investigated using various combustion concepts and different SOFC configurations. [5][6][7][8][9][10][11][12][13][14][15] The effects of operational conditions on FFC performance were studied and discussed in these early experimental studies. In a previous study, an FFC unit was implemented and studied by integrating a porous media burner with a micro-tubular SOFC. 16 In an FFC unit, the anode of the micro-tubular SOFC is directly integrated with the fuel-rich flame. The chemical and electrochemical reactions, as well as the heat transport, are coupled between the anode and the fuel-rich flame. The coupling effects will further influence the combustion characteristics of the porous media burner as well as the electrochemical performance of the SOFC. However, it is a difficult task to clarify the coupling effects via experimental methods due to the chemical and thermal complexity within the FFC unit. 17 Consequently, a modeling technique is necessary to clarify the complex physical and chemical processes.Compared with the vast number of experimental studies on FFCs, numerical studies have been relatively lacking. Vogler et al. developed a computational model of an FFC based on a flat-flame burner and a planar SOFC. 17 They found that the products of the electrochemical conversion in the SOFC did not influence the flame, and that the flame and the SOFC were chemically decoupled. However, this conclusion was drawn given the fact that a stagnation flame takes place at a certain flamelet that was far away from the SOFC. However, when a porous media burner was applied in the FFC unit, the fuel-rich combustion exhausts flowed along the anode of the micro-tubular SOFC, and chemical reactions still occurred due to the high temperature of the SOFC region.To that end, a modeling approach was undertaken to investigate the...

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Micro-tubular flame-assisted fuel cells for micro-combined heat and power systems

Cited by 49 publications

References 25 publications

Micro-tubular flame-assisted fuel cells

Micro-tubular flame-assisted fuel cells

Micro-tubular flame-assisted fuel cells running methane

Mathematical Modeling of a Porous Media Burner Based Methane Flame Fuel Cell

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