Direct Carbon Fuel Cell

Top PDF Direct Carbon Fuel Cell:

An Available Method Utilizing the Waste Heat in a Direct Carbon Fuel Cell

An Available Method Utilizing the Waste Heat in a Direct Carbon Fuel Cell

Compared with the prevailing hydrogen fuel, carbon is more convenient for storage and transportation and is less fire/explosion hazard. DCFC (direct carbon fuel cell) is a unique electrochemical device which can directly converts the chemical energy of carbon or biomass into electricity without the need for gasification or the moving machinery associated with conventional electric generators [4-6]. Almost all the carbon-rich materials such as coal, natural gas, petroleum, and biomass can be easily converted or purified to the fuel of DCFC. Thus, the DCFC is considered as one of the most attractive solution in the automotive and power generation industry [6-10].
Show more

15 Read more

Performance Analysis of a Direct Carbon Fuel Cell Cogeneration System Combined with a Two-Stage Thermoelectric Generator

Performance Analysis of a Direct Carbon Fuel Cell Cogeneration System Combined with a Two-Stage Thermoelectric Generator

A new cogeneration system model consisting of a DCFC (direct carbon fuel cell), a TTEG (two-stage thermoelectric generator) and a regenerator is proposed, where the DCFC directly and efficiently converts the chemical energy of carbon into electricity and waste heat, and the TTEG harvests the waste heat for additional electricity production. For a given heat flow rate, the TTEG is optimized using maximum power output as an objective function. An analytic relationship between the operating current density of DCFC and the dimensionless electric current of optimized TTEG is derived. The mathematical formulas for the power output and efficiency of the cogeneration system are specified under different operating conditions. The proposed hybrid system is found to be more efficient than the sole DCFC and DCFC-TEG hybrid system. It is found that the maximum attainable power density allows about 50% larger than that of the stand-alone DCFC. Furthermore, the effects of operating current density, operating temperature, heat conductivity, number of thermocouples, figure of merit of the thermoelectric materials and DCFC anode dimension on the cogeneration system performance are discussed in detail.
Show more

17 Read more

Mechanism of enhanced performance on a hybrid direct carbon fuel cell using sawdust biofuels

Mechanism of enhanced performance on a hybrid direct carbon fuel cell using sawdust biofuels

One of the most efficient ways to utilize sawdust are direct carbon fuel cells (DCFC), in which solid carbon energy is converted into electricity at 80% efficiency[4], higher efficiencies than most other conversion technologies. The molten carbonate and solid oxide electrolyte based DCFC prototypes have been extensively studied[5, 6]. A recent design is the hybrid direct carbon fuel cell (HDCFC), which is a composite of a solid oxide fuel cell and molten carbonate fuel cell which gives higher power density by extending active reaction sites and limiting the cathode corrosion[7, 8].
Show more

21 Read more

A Study of Direct Carbon Fuel Cell/Heat-Driven Refrigerator Coupled System

A Study of Direct Carbon Fuel Cell/Heat-Driven Refrigerator Coupled System

This paper presents a general framework of coupled power system composed of heat driven refrigerator and direct carbon fuel cell (DCFC). Based on the three heat source refrigerator and DCFCs pattern, the efficiency and equivalent power output of the coupled system are obtained. By numerical calculation, some expressive curves of the coupled system are analyzed. The conclusions show that the performance of the coupled system of DCFC/heat driven refrigerator is stronger than that of single fuel cell during the operating interval.

7 Read more

Biomass Fuels for Direct Carbon Fuel Cell with Solid Oxide Electrolyte

Biomass Fuels for Direct Carbon Fuel Cell with Solid Oxide Electrolyte

The XRD pattern of the pellet heated at 850oC in argon flow gas revealed the presence of very small amounts of nonstoichiometric phase NixC and of unknown phase as a product of undesirable reaction (Fig.6a). This observation is in rather good agreement with the conclusion of T. Horita which postulate possible formation of nickel carbide (Ni3C) in the conditions of the DC-SOFC operation. To explain how this phenomenon affects the performance of the fuel cell, additional investigations are required, especially these performed in long durations of DC-SOFC operating. The Fig 6b. presents the X-ray diffraction pattern recorded for sample (mixture Ni and C) heated at the same conditions but under CO2 gas flow. In this case only Ni and impurities of NiO phase were observed. These results clearly showed that further investigations of chemical stability of the Ni-YSZ anode in contact with carbon powder during conditions typical for operating the DC-SOFC are required.
Show more

25 Read more

Development of tubular hybrid direct carbon fuel cell and pyrolysis of biomass for production of carbon fuel

Development of tubular hybrid direct carbon fuel cell and pyrolysis of biomass for production of carbon fuel

In conclusion, the use of these types of fuel (coal, oil and natural gas), technology that combusts fuel to produce energy and the sharp increase in total global population are responsible for the rapidly worsening state of the environment, economy and human health. Furthermore, the demand for energy is growing so quickly that the fuel reserves are not enough to provide energy for the next few centuries. For all of these reasons, new energy sources must be studied and improved in order to make all countries energetically independent. Currently, clean sources of energy and technology called ‘renewable energy’ are being used to reduce the effect of pollution. However, they are not yet well- developed enough to totally replace convention fuel, despite the fact that in the last 20 years the use of renewable energy has grown to reach 16% of the total energy supplied to the world, with 10% coming from traditional biomass which is used primarily for heating, 3.4% from hydroelectricity and 2.6% from solar panels and wind turbines [20].
Show more

297 Read more

Electrochemical performance of different carbon fuels on a hybrid direct carbon fuel cell

Electrochemical performance of different carbon fuels on a hybrid direct carbon fuel cell

Recently hybrid direct carbon fuel cells (HDCFC) has attracted great attention, combining the advantages of solid oxide fuel cells and molten carbonate fuel cells, to convert energy of carbon to electricity directly without chemical combustion. In this work, three processed carbon fuels including activated carbon, carbon black and graphite have been employed to investigate influence of the chemical and physical properties of carbon on the HDCFC performance in different anode atmospheres at 650–800 °C. The results reveal that the electrochemical activity is strongly dependent on crystalline structure, thermal stability and textural properties of carbon fuels. The activated carbon samples demonstrate a better performance with a peak power density of 326 mW cm -2 in CO 2 at 750 °C, compared to 147 and 59 mW cm -2 with carbon black
Show more

23 Read more

Investigation of Pretreated Switchgrass, Corn Stover, and Hardwood Fuels in Direct Carbon Fuel Cells

Investigation of Pretreated Switchgrass, Corn Stover, and Hardwood Fuels in Direct Carbon Fuel Cells

An electrolyte-supported direct carbon fuel cell, with a multi-layered LSCF cathode and a dense/porous GDC anode layer, was used for testing different biomasses with various pretreatments. Initial experiments were focused on establishing a testing baseline using carbon black and coal as the carbon source. The performance of raw and pretreated switchgrass with different thermal processes (torrefaction and pyrolysis) was assessed. The low performance obtained in the cells tested with raw switchgrass indicated the efficacy of a thermal pretreatment of the biomass. However, it was demonstrated that the increase of the pretreatment temperature beyond that for torrefaction does not have a positive effect on the utilization of the switchgrass in the fuel cell. Indeed, the performance of the cell at a voltage of 0.7 V and 800°C decreased by 20% when utilizing pyroylized switchgass as the fuel. Considering torrefaction as the most suitable pretreatment process for swtichgrass (not only in terms of performance in the fuel cell, but also in terms of the overall energy balance of the process), this pretreatment was also applied to hardwood and corn stover. The performance of those fuels was similar, but slightly lower than that obtained using torrefied switchgrass. These results have been confirmed by evaluating both the V-I-P measurements and the anodic polarization resistance at 800°C. In order to investigate the differences in performance, the biomasses have been fully characterized in terms of surface area (BET), microscopy (SEM), proximate and ultimate analysis, and trace elemental analysis through acid digestion and ICP-OES. Relating the performance of the cells with the characteristics of the biomass, it was demonstrated that neither the surface area nor the amount of fixed carbon in the fuel exhibited a positive influence in the performance of the cell. Sulfur was in low concentration (if any) in the samples. The presence of the trace elements in the samples does not appear to show any catalytic or poisoning activity. The influence of potassium (well-known as an active catalyst for the oxidation of carbon) contained in the biomass showed low influence on performance, since the high potassium level in the carbonate anode mixture masked any effect.
Show more

19 Read more

Ceramic Electrolytes in the CeO2-Gd2O3-SrO System – Preparation, Properties and Application for Solid Oxide Fuel Cells

Ceramic Electrolytes in the CeO2-Gd2O3-SrO System – Preparation, Properties and Application for Solid Oxide Fuel Cells

There is growing interest in direct carbon fuel cell technology, which has allowed us to directly convert the chemical energy of carbon fuel into electricity, without burning and the emission of toxic and greenhouse gases. All the work on DCFC fuel cells is aimed at a practical and economically feasible conversion of carbonaceous solids (coal, biomass, municipal solid waste, char, etc.) directly into electric power [16-19].

16 Read more

Electrocatalytic Properties of Carbon Nanofiber Web–Supported Nanocrystalline Pt Catalyst as Applied to Direct Methanol Fuel Cell

Electrocatalytic Properties of Carbon Nanofiber Web–Supported Nanocrystalline Pt Catalyst as Applied to Direct Methanol Fuel Cell

The structure and composition of metal nanoparticles on carbon nanofiber supports are very important because they have a great effect on its catalytic activity. X-ray diffraction patterns of bare CNF web and Pt nanoparticles coated CNF webs under different sweep times are shown in Fig.1. The results clearly showed amorphous behavior for the bare CNF with a broad peak at 23° corresponds to the (002) planes of graphitized CNF. Upon Pt incorporation, the crystallinity was found to be increased. In the case of small sweep time of 5, two minute peaks were observed at 39.75° and 46.27° along (111) and (200) crystallographic directions. This shows the growth of Pt particles over CNF web. Upon increase of sweep time from 5 to 10, the intensity of these peaks was found to increase. In addition to these two peaks, three peaks were also observed at 67.64°, 81.47° and 85.8° along (220), (311) and (222), respectively. Subsequent increment in sweep time leads to the increase in intensity of these peaks. All the four peaks were similar to the results obtained by Yanhui Xu et al [31] for Pt
Show more

12 Read more

Platinum Based Catalysts on Various Carbon Supports and Conducting Polymers for Direct Methanol Fuel Cell Applications: a Review

Platinum Based Catalysts on Various Carbon Supports and Conducting Polymers for Direct Methanol Fuel Cell Applications: a Review

Over the past decade, many researchers have focused their research on the development of electrocatalyst in order to enhance its electrocatalytic activity in methanol MOR for DMFC system [37, 38]. Platinum (Pt) is a single-metal catalyst that shows significantly high cata- lytic activity for the MOR. However, pure Pt alone in a DMFC system may be easily poisoned by the intermedi- ate species, i.e., carbon monoxide (CO), and the high cost of the Pt catalyst limits its commercial application as an electrocatalyst, thereby lowering the kinetic rate of methanol oxidation in DMFC system [48–50]. These three points are the main obstacles and limitations of using Pt alone as an electrocatalyst for DMFC. However, to overcome these hindrances, several studies have been conducted to synthesize Pt-based alloy electrocatalysts to achieve better electrocatalytic performance with less Pt usage [11, 47, 51, 52]. Normally, the average size of Pt particles and its morphology can be determined through scanning emission micrograph (SEM) or transmission electron micrograph (TEM) analysis, which are most common methods in catalysis field that can be used to characterize the physical properties of electrocatalysts. Table 1 shows the average particle sizes of the Pt parti- cles with different of synthesis methods, properties, and their performances.
Show more

25 Read more

Performance of Porous Carbon as Catalyst Support for Anode from Rice Husk in a Direct Methanol Fuel Cell

Performance of Porous Carbon as Catalyst Support for Anode from Rice Husk in a Direct Methanol Fuel Cell

This paper tried proposes a novel method for producing a new porous carbon as catalyst support for DMFC with RH, which is an agricultural by-product. To analyze the structure of the porous carbon from RH, nitrogen adsorption-desorption curves were used to calculate the specific surface area and pore volume. And the surface of the porous carbon from RH was examined by means of SEM and FE-TEM. The properties of the catalyst were analyzed through the XRD pattern. Also, cycle voltammetry, anode stripping method, and single-cell test were used for electrochemical analysis of the PtRu/C catalyst. The results show the first attempts to use porous carbon from RH as catalyst support for fuel cells.
Show more

15 Read more

Experimental and modeling study of high performance direct carbon solid oxide fuel cell with in situ catalytic steam carbon gasification reaction

Experimental and modeling study of high performance direct carbon solid oxide fuel cell with in situ catalytic steam carbon gasification reaction

Electric potentials are specified at the two electrodes while two ends of the cell are electrically insulated. Inflow gas mole fraction and flow rate (SCCM) are given at the inlets. The outflow condition is specified at the outlets of the gas channels. Zero flux is specified at the end of the electrodes and pressure condition is specified at the outlets of the two gas channels. The model is solved at given operating conditions such as electric potentials, temperature, inlet gas flow rate and mole fraction. The output of the model includes distributions of the electrochemical reaction rates, chemical reaction rates and mole fraction of gas species in the cell. The commercial software COMSOL MULTIPHYSICS ® is employed for the numerical
Show more

37 Read more

Molten Metal Anodes for Direct Carbon-Solid Oxide Fuel Cells

Molten Metal Anodes for Direct Carbon-Solid Oxide Fuel Cells

44 Next, the current generated by the cell was measured while decreasing the potential at 10 mV/s. After the cell potential reached zero, the potential was ramped up at 10 mV/s. The data shows that the current reached a maximum as the potential was lowered and then began to decrease. The decrease in current was not reversed by increasing the potential. In fact, the observed currents were much lower than before. Results obtained at 1073 K were qualitatively similar to those at 973 K as shown in Fig. 2.1. The impedance measurements in Fig. 2.2 demonstrate that the changes occurring in the cell are associated with the anode. Figure 2.2a is the Cole–Cole plot of the reduced cell at 973 K in dry He before applying any current. The high frequency intercept with the real axis, which corresponds to the ohmic resistance of the cell, occurs at 5.37 Ω.cm 2 and is reasonably close to the expected value of 4.7 Ω.cm 2 for the measured YSZ electrolyte thickness of this cell, 890 µm, based on tabulated conductivity of YSZ at 973 K, 0.0188 S/cm 6 . The non-ohmic impedance, determined from the difference between the low and high frequency intercepts, is approximately 3 Ω.cm 2 . Because the contribution from the LSF-YSZ cathode at this temperature is between 0.1 and 0.2 Ω.cm 2
Show more

122 Read more

Platinum Nanoparticles Supported on Carbon Nanodots as Anode Catalysts for Direct Alcohol Fuel Cells

Platinum Nanoparticles Supported on Carbon Nanodots as Anode Catalysts for Direct Alcohol Fuel Cells

particle sizes below 10 nm [1,2].They generally possess a sp 2 conjugated core and contain suitable oxygen content in the form of multiple oxygen-containing functional groups such as carboxyl, hydroxyl and aldehyde. Synthesis of carbon nanodots can be classified into two main groups: Top down (chemical) and bottom up (physical) methods [3,4]. The top-down method employs treating starting materials such as graphite powder or multi-walled carbon nanotubes (MWCNTs) in harsh chemical conditions [4]. Bottom-up approach involves applying external energy such as ultrasonication [5], microwave pyrolysis [6] and hydrothermal treatment of small molecules such as starch [7], citric acid [8] glucose [5] and leeks [9]. CNDs have widely been applied in bioimaging [2, 10-13] , sensing [9-11,13,14],catalysis [8,15,16] optoelectronics [17] and energy conversion [5,16,18]. In this work, we report the use of CNDs as an electrocatalyst support material in direct alcohol fuel cells. Direct alcohol fuel cells (DAFCs) are attractive as power sources, they employ low molecular weight cheap green fuels [19,20]. They have fascinating advantages such as high efficiency, high energy density [21], low working temperature [22], greatly simplified design [23] and quiet operation without vibration or noise. Ethanol is an attractive liquid fuel for sustainable energy systems since it is renewable [22,23,26] cheap and non-toxic [27]. Methanol, on the other hand, has been considered the most promising fuel because it is more efficiently oxidized than other alcohols. The challenges hindering the commercialization of DAFCs includes the poor alcohol electro-oxidation reaction kinetics [27,28], the poisoning effect of the anode catalysts by some intermediates, such as adsorbed CO [31-34] and the high cost of the platinum electrocatalyst [34,35]. These problems could be resolved by using nano- scale platinum, platinum alloys and/or platinum-free catalysts [38]. The activity of a catalyst for alcohol electro-oxidation depends on the particle size distribution and dispersion of catalyst and closely linked to the characteristics of the support used [4,39]. A good support material should have a high surface area which may be obtained through high porosity. It should also bond and interact with the electrocatalysts to improve the activity and durability of the metal nanoparticles [40]. In addition, the support material for a fuel cell catalyst must have sufficient electrical conductivity so that the support can act as a path for the flow of electrons [41]. Supporting electrolytes such as NaOH, KOH, H 2 SO 4 or HClO 4 play a vital role in determining the overall fuel cell performance. Hence stability and
Show more

14 Read more

Application of infiltrated LSCM GDC oxide anode in direct carbon/coal fuel cells

Application of infiltrated LSCM GDC oxide anode in direct carbon/coal fuel cells

and/or CO gases (liberated from xerogel or from gasification reactions) in the anode electrochemical reactions which stabilises the cell performance. After 1.5h, the current density gradually declines and levels off to ~3mA cm -2 at the end of the test which lasts for 17hrs in total without interruption in the middle. A decrease in OCV value from 1.12V to 1.06V was noticed before and after the potentiostatic operation. This latter value is close to the equilibrium for carbon oxidation at 750 o C, consequently, carbon oxidation seems to be residual process on HDCFC anode, but at a sluggish kinetics. The phenomena mentioned above is supported by the impedance comparison before and after stability test, shown in Fig. 8(b). An extremely large cell resistance is observed after ~17hrs discharge at 0.7V, with both the high frequency arc characterized at 3000Hz and the other one at low frequency zone significantly larger than those before discharge.
Show more

25 Read more

Fabrication of Electrical Conductive NiCu– Carbon Nanocomposite for Direct Ethanol Fuel Cells

Fabrication of Electrical Conductive NiCu– Carbon Nanocomposite for Direct Ethanol Fuel Cells

microscope (TEM) (JEOL Ltd., Japan) equipped with EDX for the investigation of the crystallinity of nanocomposite. X-ray diffraction technique with Cu Kα (λ=1.54056 Å) (Rigaku Co., Japan) was used to determine the crystallinity structure of nanocomposite. The catalytic activity of introduced nanocomposite was achieved by using an electrochemical cell with three-electrode system. The synthesized nanocomposite, platinum wire, and Ag/AgCl were used as working electrode, counter electrode, and reference electrode, respectively. The catalytic activity was measured using the cyclic voltammetry test (CV) in 1 M KOH solution. The sweep potential ranged from 0 to 0.8 V. 2 mg from nanocomposite powder was mixed with 20 μL Nafion solution (5 wt%) and 400 μL isopropanol. 15 μL from the prepared slurry was poured on the glassy carbon electrode (GCE). Electrode was dried at 80
Show more

8 Read more

Role of coal characteristics in the electrochemical behaviour of hybrid direct carbon fuel cells

Role of coal characteristics in the electrochemical behaviour of hybrid direct carbon fuel cells

Studies reported so far about DCFCs have put much emphasis on analysing the influence of the fuel properties on the cell performance. Due to the complexity of these systems that operate with solid fuels, especially in the case of HDCFCs where two electrolytes are present, carbons or homogeneous carbon materials with very well-known properties are normally used, such as activated carbons, carbon black or graphite. However, as some researchers have pointed out, real world fuels, such as coals, should be investigated in order to achieve the industrial application of the DCFCs. 4 In this regard, studies evaluating different fuel possibilities, like biomass, refuse fuels or coals, are beginning to emerge. However, the information currently available is still little and not sufficient to understand the reaction mechanism of DCFCs, especially in the case of HDCFCs. Therefore, a more systematic analysis is required to gain a deeper understanding of how properties of a material as heterogeneous as coal impact on the HDCFCs behaviour. This will help to determine the most appropriate coals and their possible pre-treatments to improve their electrochemical reactivity and, thereby, to finally achieve a commercial implementation of this technology.
Show more

14 Read more

Waste Water Treatment in Direct Borohydride Fuel Cell with Bipolar Membrane

Waste Water Treatment in Direct Borohydride Fuel Cell with Bipolar Membrane

Electrode made of carbonaceous fiber covered by non-catalyzed carbon black layer “BlackPearls 2000” (ElectroCellAB) was used as cathode. Electrode 40% Pt 0.5 mg/cm 2 with XC 72R carbonaceous black on Car- bon Cloth was used as an anode. Anode and cathode compartments of DBFC were separated with bipolar mem- brane Fumasep ® FBM (Fumatech Inc.). UV irradiation was performed by the use of quartz construction “tube in tube”, that was placed in circulation contour of a catholyte. UV lamp with wave length 253 nm (8 W) was placed into inner tube, catholyte circulated between tubes. Current, voltage and pH were measured by M2015 ammeter, M106 high-resistance voltmeter and HI 8424 microcomputer pH-meter, correspondingly.
Show more

12 Read more

State of Research Developments in Direct Methanol Fuel cell

State of Research Developments in Direct Methanol Fuel cell

Lu et al. [20] developed a carefully designed transparent DMFC to visualize, in situ, the bubble flow in the anode of a DMFC. Normally, the transparent cells used in the visualization studies are constructed with a pair of stainless steel plates mated with a polycarbonate plate, forming a window to allow direct observation of flow behaviour. The polycarbonate plate is concave in design while the stainless steel plate had a matching convex pattern to avoid flow leakage. The channels are machined through the stainless steel plate and the surface that contacts with the MEA are coated with Cr (Chromium) and Au (Gold) to minimize the contact resistance. They used two types of MEAs based on Nafion 112 to investigate the effects of the backing pore structure and wettability on cell polarization and two-phase flow dynamics. One employed hydrophobic carbon paper backing material and the other hydrophilic carbon cloth. For the hydrophobic carbon paper they observed that carbon dioxide bubbles nucleate at certain locations and form large and isolated bubble slugs in the channel. For the hydrophilic carbon cloth it was shown that bubbles are formed more uniformly and of smaller size.
Show more

13 Read more

Show all 10000 documents...