Energy saving fuel elements with used hydrogen.

Abstract

Performed research work to determine the effect on the fuel cells of the temperature and change the shape of the elements (plates) in contact with hydrogen. It has been confirmed that the plate change takes two stages. In the first short time step, the maximum form of plate change is achieved. The temperature-dependence of the maximum bending of the plate obeys the extreme law. In the second, substantially longer phase, the plate is straightened. At low temperatures, the residual stationary bending of the plate is 20-30% of the maximum bending value. With increasing temperature, the bending rate of the plate increases and at 320-350oS the phenomenon becomes completely reversible. The mechanism of changing fuel cell form is discussed. As a result of the study, the experimental regularities of the hydrogen-induced form of change of the palladium plate are established, it is determined that a temporary "metal-hydrogen" gradient material is formed at hydrogen saturation and hydrogen concentration stresses always arise. This, in turn, provides for efficient planning and determination of the time of penetration of hydrogen into the metal, controlling the shape change, and allowing the fuel cell to operate. It is determined that the maximum bending of the plate with increasing temperature changes according to the extreme law and in the temperature range 220-260oS the bending reaches the maximum value. It is shown that the maximum bending of the plate is determined by two fundamental properties of the Pd-H system, namely, the diffusion coefficient and the equilibrium solubility of hydrogen in palladium. The scientific novelty is the use of the known material palladium, which in contact with hydrogen becomes a temporary gradient alloy with variable physical properties. It is established that the heat exchange in the plate and the energy equilibrium around the plate are based on the velocity on the heat flux that occurs during reactions in the fuel cells and the heat losses that occur in the fuel cell. The practical importance of the work lies in the possibility of using the developed algorithm in practice in the manufacture of specific devices operating on the basis of a fuel cell - hydrogen, with the possibility of modeling this process in Matlab. But improving the working conditions of fuel cells and hydrogen sensors, because at low temperatures there is a relatively small residual bending of the plate, and accordingly the shape of the fuel cell.