Performance assessment of a direct formic acid fuel cell system through exergy analysis

Reis, Alper; Mert, Suha Orçun

doi:10.1016/j.ijhydene.2015.07.131

Cited by 16 publications

(6 citation statements)

References 32 publications

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“…pumps has to be taken into account. The value can thus be considered to be consistent with the value of 24% estimated by Reis and Mert for exergetic (not energetic) efficiency …”

Section: Energy Balancesupporting

confidence: 88%

Hydrogen Storage in Formic Acid: A Comparison of Process Options

2017

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Formic acid (53 g H2/L) is a promising liquid storage and delivery option for hydrogen for fuel cell power applications. In this work we compare and evaluate several process options using formic acid for energy storage. Each process requires different steps, which contribute to the overall energy demand. The first step, i.e. production of formic acid, is thermodynamically unfavorable. However, the energy demand can be reduced if a formate salt is produced via a bicarbonate route instead of forming the free acid from hydrogen and carbon dioxide. This bicarbonate/formate approach also turns out to be comparatively more efficient in terms of hydrogen release than the formic acid route even though less energy efficient, catalytic decomposition of formic acid has the advantage of reaching higher volumetric power densities during hydrogen release. Efficiencies of all process options involve aqueous media and are dependent on concentration. Heating water leads to additional energy demand for hydrogen release and thus lowers the overall efficiency. Separation and purification of hydrogen contribute a minor impact to the overall energy demand. However, its effect on efficiency is not negligible. Other process options like thermal decomposition of formic acid or direct formic acid fuel cells thus far do not appear competitive.

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“…pumps has to be taken into account. The value can thus be considered to be consistent with the value of 24% estimated by Reis and Mert for exergetic (not energetic) efficiency …”

Section: Energy Balancesupporting

confidence: 88%

Hydrogen Storage in Formic Acid: A Comparison of Process Options

2017

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“…The increasing power density values resulted from the higher Nafion-117 conductivity associated with a higher temperature, leading to a slower decline in ohmic loss (Figure 2a). The result confirms that by increasing the temperature, the efficiency of the power densities was also increased due to the activation overpotential produced in the electrolyte membrane [12]. The predicted power density data using the modified model were in excellent agreement with the experimental results for the entire temperature range.…”

Section: Effect Of Formic Acid Concentration On Cell Performance Usinsupporting

confidence: 78%

“…Perales-Rondón et al demonstrated the formic acid oxidation mechanism of different Pt single crystal electrodes using extensive density functional theory (DFT) calculations and the proposed theoretical values were validated with experimental results [11]. Recently, Reis et al reported the system model and simulated this by using sub-routine development that made predictions through a wide variety of operating parameters, such as membrane thickness, electrode stoichiometry, pressure, temperature, current density and reference properties for DFAFC [12]. Ha et al introduced an empirical model to demonstrate the cell performance difference between active and passive DFAFCs [13].…”

Section: Introductionmentioning

confidence: 99%

Experimental and One-Dimensional Mathematical Modeling of Different Operating Parameters in Direct Formic Acid Fuel Cells

et al. 2017

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Abstract:The purpose of this work is to develop a one-dimensional mathematical model for predicting the cell performance of a direct formic acid fuel cell and compare this with experimental results. The predicted model can be applied to direct formic acid fuel cells operated with different formic acid concentrations, temperatures, and with various electrolytes. Tafel kinetics at the electrodes, thermodynamic equations for formic acid solutions, and the mass-transport parameters of the reactants are used to predict the effective diffusion coefficients of the reactants (oxygen and formic acid) in the porous gas diffusion layers and the associated limiting current densities to ensure the accuracy of the model. This model allows us to estimate fuel cell polarization curves for a wide range of operating conditions. Furthermore, the model is validated with experimental results from operating at 1-5 M of formic acid feed at 30-80 • C, and with Nafion-117 and silane-crosslinked sulfonated poly(styrene-ethylene/butylene-styrene) (sSEBS) membrane electrolytes reinforced in porous polytetrafluoroethylene (PTFE). The cell potential and power densities of experimental outcomes in direct formic acid fuel cells can be adequately predicted using the developed model.

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Section: Introductionmentioning

confidence: 99%

“…Fuel cells are a relatively new type of energy converters that converts chemical energy into electrical energy with relatively high efficiency and developed in the second half of the 20th century. 12 The difference between a fuel cell and a typical battery is that, a fuel cell continues to produce energy if fuel and oxidant are supplied unlike a typical battery which ultimately goes dead. Several types of fuel cells are classified by the kind of electrolyte, electrochemical reactions that take place in the cell, the temperature range in which the cell operates, and the fuel required.…”

Section: Introductionmentioning

confidence: 99%

Formic acid synthesis and utilization for solar energy storage through solar‐driven chloralkali process and fuel cells

Mardini

Biçer

2021

Energy Storage

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The objective of this work is to propose an integrated system for formic acid synthesis via photovoltaic (PV) assisted‐chloralkali process and clean power generation by the fuel cell. The initial step is to develop process flow diagrams and to apply heat integration techniques to conserve energy in the synthesis of formic acid and direct formic acid fuel cell (DFAFC). The proposed system forms formic acid from gaseous H2 produced from chloralkali unit and captured CO2. The electricity requirements of both PV‐assisted chloralkali and compression stages are supplied from the PV units. The results imply that the chloralkali process necessitates about 7.22 MW power to produce hydrogen at 25°C and 1 bar with an energy efficiency of 84%. H2 and CO2 gases are compressed to 60 bars with a total energy requirement of 951 kW. In the heat integration part, different scenarios are developed to determine the minimum heating and cooling requirements for maximum heat recovery. The results of such heat integration were achieved to conserve the energy in the formic acid process with total hot and cold utilities of 599 kW and 1884 kW, respectively.

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Performance assessment of a direct formic acid fuel cell system through exergy analysis

Cited by 16 publications

References 32 publications

Hydrogen Storage in Formic Acid: A Comparison of Process Options

Hydrogen Storage in Formic Acid: A Comparison of Process Options

Experimental and One-Dimensional Mathematical Modeling of Different Operating Parameters in Direct Formic Acid Fuel Cells

Formic acid synthesis and utilization for solar energy storage through solar‐driven chloralkali process and fuel cells

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