Hydrogen gas (density = 1.165 kg/m^3 ) is stored at 25°C in a permeable cylindrical container which has an outer diameter of 0.25 m, a wall thickness of 5 mm and a length of 2 m. The cylinder is exposed to ambient air.
If the container is charged to an initial pressure of 5 bars, at what would be the mass diffusion rate (in kg/s) of hydrogen through the cylinder? Hydrogen solubility in the container is 0.5X10^(-3) kmol/m^3 bar and diffusivity at 293K and 1 bar is 0.4x10^(-13) m^2 /s.