Nickel-Based Anodes for Single-Chamber Solid Oxide Fuel Cells: A Catalytic Study
Single-chamber solid oxide fuel cells (SOFCs) are an alternative concept to traditional SOFCs. Conventional anodes, which consist of a cermet of metallic Ni and an ionic conductor, have to work under a mixture of hydrocarbon and oxygen. This paper presents a catalytic study of C 3 H 8 oxidation by Ce 0.9 Gd 0.1 O 1.95 and nickel. The influences of temperature and oxygen to propane ratio on the nickel oxidation state are clarified, thanks to catalytic tests and electrical conductivity measurements. The results show that the temperature must be higher than a critical value to maintain the nickel particles in the metallic state. Furthermore, at high temperatures, the conversion of the initial mixture leads to the water-gas-shift equilibrium.
Voltage Oscillations in Single‐Chamber Fuel Cells Operating under a C3H8/O2 Mixture
Single‐chamber fuel cells (SCFCs) are an alternative way to conventional SOFCs. Effectively, they do not require any more sealing between anodic and cathodic compartment's as the cell is fed with a mixture of hydrocarbon and oxygen. This paper deals with voltage oscillations observed with an SCFC composed of GDC (Ce0.9Gd0.1O1.95) supported electrolyte, Ni‐GDC anode and a BSCF (Ba0.5Sr0.5Co0.8Fe0.2O3–δ) cathode, operating in the temperature range 500–600 °C and under various propane and oxygen mixtures, with a C3H8/O2 ratio between 0.2 and 0.66. Electrical and Thermo‐Programmed Oxidation (TPO) measurements combined with SEM observations allowed us proving that these oscillations are due to carbon nanowires deposition/oxidation cycles. A mechanism is proposed to explain this behavior.
Numerical Simulation of Induction Heating Process of Continuous Casting Slab
Compared with traditional blazing furnace, the Continuous Casting-Direct Rolling is an advanced manufacturing steel technology, which can reduce energy waste, decrease pollution and enhance efficiency. The characteristics of steels during induction heating are complex, the change of material properties with temperature makes exact analysis methods very difficult to implement. Therefore, a powerful computer aided numerical tool (i.e., finite difference analysis) is selected to numerically model the induction heating process in this paper. The mathematic model coupling with electromagnetic field and thermal field was established, and it was solved by finite difference method (FDM), thus the slab temperature distribution and its variation with time were obtained, and the characteristics in whole induction heating process were studied. To validate the program feasible, the results were evaluated and compared with experiment results, which showed that the simulation results are reliable and effective. The skin effect in heating process from the two results was studied and demonstrated, the temperature change caused by different parameters such as the induced power intensity and the corner radian were also presented, which indicate that the slab temperature can be heated uniformly through adjusting these parameters, thus the continuous casting slab can meet the rolling requirement.