Ammonia, at 25 ◦C, flows through a pipe at a rate of V˙ = 10 m3/h. In order to maintain the pressure in the tube at 1 bar, a small tube of inner diameter 3 mm, has been welded onto the pipe, providing...

Ammonia, at 25 ◦C, flows through a pipe at a rate of V˙ = 10 m3/h. In order to maintain the pressure in the tube at 1 bar, a small tube of inner diameter 3 mm, has been welded onto the pipe, providing a link to the surrounding air, Fig. 1.60. This tube is spiral wound and 20 m long, so that the loss of ammonia by diffusion is very low. How much ammonia in m³/h is lost and what is the mole fraction of air in the large pipe? The density of ammonia is 0.687 kg/m³, the diffusion coefficient of ammonia in air at 25 ◦C is D = 0.28 · 10⁻⁴
m²/s