Simulation of the performance for the direct internal reforming molten carbonate fuel cell. Part II: comparative distributions of reaction rates and gas compositions

Abstract

SUMMARYThis study examined the distributions of the three reaction rates and the compositions of the gases at each point of the unit cell in DIR-MCFC using a numerical simulation. The electrochemical reaction rates at the anode gas entering position were almost two times faster than those at the anode gas outlet position and most of the feeding CH 4 reacted in the region from the position x ¼ 0 to the position x ¼ 0:3: In addition, the water-gas shift reaction became faster from near the half position of the unit cell to the gas outlet position. Therefore, in the rear position of the unit cell, the steam reforming reaction played an important role as a supplementary reaction for providing the H 2 needed in the electrochemical reaction. The rates of the two catalytic reactions in the case without the electrochemical reaction were relatively slower than those in the DIR-MCFC. Unlike the distributions of temperature, the current density, gas compositions and the reactions rates at each point of the DIR-MCFC cell, the exit gas compositions from the simulation in particular could be comparative to those of the experimental results. Although there was an approximately 10% difference between both of them, the extent of the difference was considered to be reasonable for this simulation considering the experimental values that could be included in this simulation such as the lower conversion of the reactions, the lower current density and any other values.

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.…”

“…39, 40 and with the experimental data found in the articles by Wee et al . 39, 40. In addition, in this case there is a good agreement between the experimental data and the data produced by the simulation model of the authors proposed in the present article.…”

“…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.…”