Internal reforming

Abstract

In addition to its high conversion efficiency, the solid oxide fuel cell (SOFC) is very attractive from the fuel flexibility point of view. Natural gas has been regarded as the most suitable fuel for the SOFC. Methane, natural gas and hydrocarbons can be readily converted upon direct introduction by a reforming reaction on the Ni/yttria‐stabilized zirconia fuel electrode in the direct internal reforming operation. Internal reforming is attractive not only from the point of view of the simple system, but also the high efficiency due to combined generation with the endothermic reforming reaction. Carbon deposition is one of the damaging factors for the cell for direct internal reforming. The carbon deposition region is determined from thermodynamic equilibrium. Even in the calculated carbon free region, deposition was sometimes observed due to decomposition of hydrocarbon and rapid growth on the Ni catalyst. The selection of the oxide component as well as a metallic component in the cermet should be effective in achieving high performance in the electrode reaction and in avoiding carbon deposition. Stress analysis has been carried out for the internal reforming operation of planar cells. Internal reforming has been successfully carried out in 1 kW planar, several tens of kilowatt scale MOLB type and 10 kW tubular type modules.

Other Fuel Cells

“…Modern PAFCs can be higher than this, as shown in Figure 7. 19. For operation in the electric mode only, around 40% chemical-to-electrical conversion is realized, which is better than many combustion systems for submegawatt power application.…”

“…High-quality waste heat combined with a bottoming or cogeneration system enables a potential for high overall system efficiencies (∼80%) utilizing a bottoming or cogeneration cycle [19]. This also provides a tolerance to a variety of fuel stocks and enables internal reformation of complex fuels.…”

“…19 Polarization curve from 200 kWe PC25 PAFC system operating at 180 • C and atmospheric pressure. Pt-CO/C supported cathode catalyst, and SiC:ZrSiO 4 electrolyte matrix.…”

Modelling of tubular-designed solid oxide fuel cell with indirect internal reforming operation fed by different primary fuels

“…Generally, SOFC is operated at high temperatures (1073-1473 K), thus hydrocarbon fuels (e.g., methane) can be applied as a primary fuel when the system is operated with internal reforming (IR-SOFC). This operation uses the heat generated from the exothermic electrochemical reaction to conduct the endothermic (steam) reforming of hydrocarbons [2][3][4][5].…”

“…Among other 0378 potential primary fuels, ethanol and methanol are also interesting candidates due to their ready availability, high specific energy, sulfur-free content and storage transportation convenience [5]; moreover, they can be produced renewably from both chemical and biological processes. In addition to these three types of fuel, biogas is another attractive candidate-particularly for agricultural countries since it is a promising renewable fuel that can be produced biologically from the waste residues.…”