Simulation of the performance for the direct internal reforming molten carbonate fuel cell. Part I: distributions of temperature, energy transfer and current density

Abstract

SUMMARYThis study examined the temperature distributions of the anode and cathode gases of the cell body as well as the current density distributions at each point of the direct internal reforming molten carbonate fuel cell (DIR-MCFC) using numerical modelling. The model was based on assumptions and experimental data from a 5 cm  5 cm sized unit cell operation. The results showed there was an approximately 138C temperature difference between the initial point (0, 0) and end point (1, 1) of the cell body and the temperature increased steadily along with the direction of the anode gas flow. The temperature distribution of the anode gases showed a similar trend to those of the cell body. The temperature of the anode gases was an average 118C lower than that of the cell body. The temperature distributions of cathode gases were relatively higher than those of the anode gases and the cell body. The temperature distributions at each point of the cell body, including the anode and cathode gases, could be explained by the different rates of the electrochemical, methane steam reforming and water-gas shift reactions at each point in the cell body. The current density distribution at the entrance of the cell was the highest at 290 mA cm À2, and decreased steadily to 150 mA cm À2 at the exit. These results were also confirmed by the amount of hydrogen reacted in the electrochemical reaction (referred to Part II). Finally, modelling simulations showed a non-uniform distribution of the temperature and current density throughout the DIR-MCFC were observed. In addition, it was confirmed that the distributions of the reaction rates and gas compositions at each point of the cell also showed a great deal of difference throughout the DIR-MCFC. The non-uniformity of these temperature distributions can lead to deterioration in the cell performance. These might provide the necessary information for solving these problems.

A methodology for improving the performance of molten carbonate fuel cell/gas turbine hybrid systems

“…Figure 3 shows the polarization curve produced by the model and points, voltage–current density measured experimentally, found in the articles by Wee et al . 39, 40. As can be seen, there is a good agreement between the values produced with the simulation model suggested in the present article, and the experimental values found in the literature.…”

“…In Table II the composition of anodic exhaust gases of the fuel cell, produced by the simulation model reported in the present article, is compared both with the same composition produced by a more detailed simulation model (two‐dimensional and stationary) as proposed in the articles by Wee et al . 39, 40 and with the experimental data found in the articles by Wee et al . 39, 40.…”

“…In order to test experimentally the simulation model for an MCFC with DIR (DIR) fed by methane reference was made to the experimental data reported in articles by Wee et al . 39, 40 among the few for an MCFC with the same considered type of reforming. In order to compare the experimental data reported in 39, 40 with the output data of the simulation model, the same values of input data used from Wee et al .…”

“…39, 40 among the few for an MCFC with the same considered type of reforming. In order to compare the experimental data reported in 39, 40 with the output data of the simulation model, the same values of input data used from Wee et al . in their experimental test, which are reported in Table I, were supplied to the MCFC calculation code.…”

Three-dimensional modeling of polarization characteristics in molten carbonate fuel cells using peroxide and superoxide mechanisms

“…Thermal conductivity of anode, k a (W m À1 K À1 ) [42,43] 78 Thermal conductivity of cathode, k c (W m À1 K À1 ) [42,43] 0.9 Thermal conductivity of electrolyte, k e (W m À1 K À1 ) [43] 2.0 Specific heat of anode, c p,a (J kg À1 K À1 ) [46] 444 Specific heat of cathode, c p,c (J kg À1 K À1 ) [46] 44,352 Specific heat of electrolyte, c p,e (J kg À1 K À1 ) [46] 4000…”