Question

The purification of hydrogen gas is accomplished by diffusion through a palladium sheet. Compute the number of kilograms of hydrogen that pass per hour through a 6-mm thick sheet of palladium having an area of 0.25 m2 at 600°C. Assume a diffusion coefficient of 1.7 × 10–8 m2/s that the respective concentrations at the high- and low-pressure sides of the plate are 2.0 and 0.4 kg of hydrogen per cubic meter of palladium, and that steady-state conditions have been attained. Express your answer in engineering format in kg/hour to two significant figure

Answer 1

Answer;

= 4.08 × 10^-3 kg/h

Explanation;

This problem calls for the mass of hydrogen, per hour, that diffuses through a Pd sheet.

M = JAt = -DAt (ΔC/Δx)

Where D = 1.7 × 10^–8 m2/s, A is area; 0.25 m², t =3600s/h

ΔC =( 0.4 - 2.0) kg/m³, Δx = 6 mm or 6 × 10^-3 m

Therefore;

= -(1.7 × 10^–8 m2/s)(0.25 m²)(3600 s/h) [(0.4 - 2.0) kg/m³)/6 × 10^-3]

= 4.08 × 10^-3 kg/h