چكيده به لاتين
The production and storage of environmentally friendly energy is one of the main problems of nowadays. Among the wide range of renewable energy options, solar energy is one of the sources that shows the potential for reducing energy supply problems. This energy source has its drawbacks, despite all the advantages, including its extreme dependence on the hours of the day, the moon, the season, and the geographical area. selecting this energy as sustainable energy requires storage. So far, many methods have been used to absorb and store solar energy, but most of these methods are very expensive and sometimes pollute the environment. In the present study, the method of storing solar energy in natural gas (methane) through the process of methane steam reforming by converting it to hydrogen was investigated. Hydrogen produced by this method can replace the hydrogen produced for daily use of this fuel or can be used as a source of solar energy. A two-dimensional steady-state axisymmetric model is developed to analyze performance of a thermochemical porous reactor. To conduct the simulation, finite volume method coupled with kinetics thermochemical reaction and Local Non-thermal equilibrium (LTNE) model with modified P1 approximation are employed to obtain the temperature distribution for both the fluid and the porous media. The study has been conducted for the certain pertinent parameters of inlet velocity, inlet steam to methane ratio, porosity, average cell diameter, and reactors length and results are investigated in terms of hydrogen generation, temperature, velocity and reaction rate distribution and a new configuration was provided for this thermochemical reactor. Numerical results indicate that, increasing inlet flow rate leads to a lower temperature and causes the reaction to perform incompletely. Also, by considering Gaussian distribution for irradiation, temperature and consequently hydrogen mole fraction is higher at the centerline of the foam compared to walls of the reactor. The configuration introduced with all the improvements, improved the reactor performance by 135%.
