Etude de conception d’un réservoir de stockage du pré-mélange hydrogène-gaz naturel comprimé.

Abstract

Considered as the energy transporter of the future, hydrogen seems to be the miracle solution to overcome the current energy and environmental crisis. This may be true provided that all the problems underlying in its life cycle (production, distribution, storage and use) are resolved. The work of this thesis is part of the theme of hydrogen storage more specifically that on board vehicles, which remains one of the most critical problems for the transition to a hydrogen-based transport system. In fact, many technological obstacles continue to slow down the deployment of its commercialization, the most important of which remains the increase in the temperature of compressed hydrogen gas (CHG), during the rapid filling of the storage tank of a vehicle. Our contribution in this vast line of research will be the examination of the possibility of setting up a model of filling a hyperbaric tank. Our attention will focus especially on the thermal phenomena that occur during this process. A two-dimensional axisymmetric computational fluid dynamics (CFD) model for the fast filling of a vehicle cylinder at 150 liter CHG and 35 MPa pressure is established. The simulation based on the standard k-ε turbulence model and the Redlich-Kwong equation of state will make it possible to study the evolution of the gas temperature during the fast filling process of the reservoir. A new fuel consisting of a mixture of Natural Gas doped with Hydrogen (HCNG) is studied. The temperature distribution of this gaseous fuel during the filling phase of a cylindrical tank is examined. Rates of 0%, 8%, 15% and 20% hydrogen were considered. The results obtained show unambiguously that the addition of hydrogen to methane leads to an increase in the temperature of the mixture during the filling process of the tank, all the more important as the rate of hydrogen is greater. In addition, it has been noted that this increase in temperature is more accentuated in the case of compressed hydrogen gas (CHG) than in that of compressed natural gas (CNG). The effect of several parameters, initial pressure, mass filling rate and filling time, on the temperature evolution of CHG was examined. Simulation results show that reducing the mass filling rate or increasing the initial pressure can significantly reduce the temperature of the compressed hydrogen (CHG) in the storage tank. Regarding the filling time, it was noted that the slower filling results in a lower gas temperature rise.