2 replies to this topic

[A mukherjee]

Hii everyone,
I have to calculate the air flow required to be removed from Prepurification unit during depressurization....Also I need to calculate the amount of air required during the repressurization of bed. Can any one give me any idea regarding this?
Thnxx in advance..

[Zauberberg]

pVM = zmRT will give provide you with a ballpark figure.

p - final pressure (re-pressurization)
V - total system volume

That will give you the total mass of air inside the system, at given conditions. The flow will not be constant (dynamic nature of pressurization/depressurization), and it will depend on the source Air pressure.

[Himanshu Sharma]

if you are using a constant pressure source for pressurization you may apply Bird stewart lightfoot or Grote equation in reverse direction.

Generation of your model with calculus is a cumbersome task ( i did it 2-3 times for my systems),However above equations work most of the times,

Linear flow equation suffice when pressure difference is not that large but else ways it has serious drawbacks for maximum flow sizing in case of RO or control valve since maximum flow that should pass thru them is way too high than by what you get as linear averaging.(try imagining sum of least squares errors)