Use of ash-free “Hyper-coal” as a fuel for a direct carbon fuel cell with solid oxide electrolyte

Dudek, Magdalena; Tomczyk, P.; Socha, Robert P.; Hamaguchi, Maki

doi:10.1016/j.ijhydene.2014.04.057

Cited by 61 publications

(30 citation statements)

References 30 publications

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“…H 2 O could not be detected by the GC, but the amount must be very small because the AFC was kept dry and the H 2 O composition in the AFC was about 2 wt% [7]. Identical gas generation behaviour for AFC has also been reported [3]. Therefore it is clear that the large mass transfer resistance of the AFC+N 2 fuel shown in Fig.…”

Section: Resultsmentioning

confidence: 82%

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Characteristics of Solid Fuel Oxidation in a Molten Carbonate Fuel Cell

Lee¹,

Kim²,

Kim³

et al. 2016

Journal of Electrochemical Science and Technology

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Oxidation behaviours of ash free coal (AFC), carbon, and H 2 fuels were investigated with a coin type molten carbonate fuel cell. Because AFC has no electrical conductivity, its oxidation occurs via gasification to H 2 and CO. An interesting behaviour of mass transfer resistance reduction at higher current density was observed. Since the anode reaction has the positive reaction order of H 2 , CO 2 and H 2 O, the lack of CO 2 and H 2 O from AFC results in a significant mass transfer resistance. However, the anode products of CO 2 and H 2 O at higher current densities raise their partial pressure and mitigate the resistance. The addition of CO 2 to AFC reduced the resistance sufficiently, thus the resistance reduction at higher current densities did not appear. Electrochemical impedance results also indicate that the addition of CO 2 reduces mass transfer resistance. Carbon and H 2 fuels without CO 2 and H 2 O also show similar behaviour to AFC: mass transfer resistance is diminished by raising current density and adding CO 2 .

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Section: Resultsmentioning

confidence: 82%

“…Since AFC has no electric conductivity, it only works as a fuel by gasification to H 2 and CO. Most AFC oxidation was carried out in a DCFC (direct carbon fuel cell) based on SOFC (solid oxide fuel cell) technology [3,4]. To date, no report is available for a DCFC run by AFC based on MCFC technology.…”

Section: Introductionmentioning

confidence: 99%

Characteristics of Solid Fuel Oxidation in a Molten Carbonate Fuel Cell

Lee¹,

Kim²,

Kim³

et al. 2016

Journal of Electrochemical Science and Technology

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“…The data for de-ashed coal (Hyper-coal, HP Japan) have also been added [31,32] As a result of the analysis of data presented in Figure 10, it can be stated that the highest values of Pmax were recorded for DC-SOFC (1) supplied with upgraded coal (with ash content no higher than 5 wt.%). The values are close to Pmax obtained for the same DC-SOFC (1) supplied with Hyper-coal samples [31,32] or carbon black samples (CB2).…”

Section: Resultsmentioning

confidence: 99%

“…In the case of cell (2), carbon can be oxidised according to reaction (1) as well as in a sequence of reactions (2) and (3): C + CO2→ 2CO (2) and CO + O 2-→ CO2 + 2e -(3) [31]. In this section, the electrochemical performance of DC-SOFC (2) supplied with coal samples will be discussed.…”

Section: Electrochemical Oxidation Of Carbon-based Solid Fuels On Thementioning

confidence: 99%

Utilisation of coal for energy production in fuel cells

et al. 2016

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Abstract. In this paper a brief characterization of fuel cell technology and its possible application in sustainable energy development was described. Special attention was paid to direct carbon fuel cell technology. The direct carbon fuel cell is an electrochemical device which directly converts the chemical energy of carbonaceous based fuel into electricity without 'flame burning'. The electrical efficiency of a DCFC is indeed very high (in practice exceeding 80%), and the product of conversion consists of almost pure CO2, eliminating the most expensive step of sequestration: the separation of carbon from flue gases. In this paper the process of electrochemical oxidation of carbon particles on the surface of oxide electrolytes at 8% mol Y2O3 in ZrO2 (8YSZ) as well as cermet anode Ni-8YSZ was analysed. The graphite, carbon black powders were considered as reference solid fuels for coal samples. It was found that the main factors contributing to the electrochemical reactivity of carbon particles is not only the high carbon content in samples but also structural disorder. It was found that structurally disordered carbon-based materials are the most promising solid fuels for direct carbon solid oxide fuel cells. Special impact was placed on the consideration of coal as possible solid fuels for DC-SOFC. Statistical and economic analyses show that in the coming decades, in developing countries such as China, India, and some EU countries, coal-fuelled power plants will maintain their strong position in the power sector due to their reliability and low costs as well as the large reserves of coal and lignite in the world. Coal is mined in politically stable areas, which guarantees its easy and safe purchase and transport. The impact of the physiochemical properties of raw and purified coal on the performance of the DC-SOFC was studied. An analysis of the stability of electrical parameters was performed for a DC-SOFC operating under a load over an extended period of time. The tests indicated that DC-SOFCs fed with de-ashed coal were characterized by stable operation, with a power density greater than 100 mW/cm 2 from a single cell.

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“…The surface chemistry is considered to play a vital role in such applications and hence the modification of surface chemistry by various treatments is seen as a promising way for improved performance of carbon materials in catalysis, adsorbent and energy storage applications. In the case of DCFC as well, the modification of the surface functional group or surface activation of carbon fuel is thought to influence the performance [37].…”

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confidence: 99%

Progress and Challenges in the Direct Carbon Fuel Cell Technology

Chen

Gao

Long

et al. 2015

ILCPA

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Fuel cells are under development for a range of applications for transport, stationary and portable power appliances. Fuel cell technology has advanced to the stage where commercial field trials for both transport and stationary applications are in progress. Direct Carbon Fuel Cells (DCFC) utilize solid carbon as the fuel and have historically attracted less investment than other types of gas or liquid fed fuel cells. However, volatility in gas and oil commodity prices and the increasing concern about the environmental impact of burning heavy fossil fuels for power generation has led to DCFCs gaining more attention within the global study community. A DCFC converts the chemical energy in solid carbon directly into electricity through its direct electrochemical oxidation. The fuel utilization can be almost 100% as the fuel feed and product gases are distinct phases and thus can be easily separated. This is not the case with other fuel cell types for which the fuel utilization within the cell is typically limited to below 85%. The theoretical efficiency is also high, around 100%. The combination of these two factors, lead to the projected electric efficiency of DCFC approaching 80% -approximately twice the efficiency of current generation coal fired power plants, thus leading to a 50% reduction in greenhouse gas emissions. The amount of CO 2 for storage/sequestration is also halved. Moreover, the exit gas is an almost pure CO 2 stream, requiring little or no gas separation before compression for sequestration. Therefore, the energy and cost penalties to capture the CO 2 will also be significantly less than for other technologies. Furthermore, a variety of abundant fuels such as coal, coke, tar, biomass and organic waste can be used. Despite these advantages, the technology is at an early stage of development requiring solutions to many complex challenges related to materials degradation, fuel delivery, reaction kinetics, stack fabrication and system design, before it can be considered for commercialization. This paper, following a brief introduction to other fuel cells, reviews in detail the current status of the direct carbon fuel cell technology, recent progress, technical challenges and discusses the future of the technology.

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Use of ash-free “Hyper-coal” as a fuel for a direct carbon fuel cell with solid oxide electrolyte

Cited by 61 publications

References 30 publications

Characteristics of Solid Fuel Oxidation in a Molten Carbonate Fuel Cell

Characteristics of Solid Fuel Oxidation in a Molten Carbonate Fuel Cell

Utilisation of coal for energy production in fuel cells

Progress and Challenges in the Direct Carbon Fuel Cell Technology

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