Air-lift Pump Sizing

[TexasCHe]

PLEASE CHECK THEORY AND ASSUMPTIONS

I have four air-lift pumps operating simultaneously. The injection points are ~ten feet under the water surface and each of the pumps appears to move about 75 GPM. I figure what appears to be 75 GPM is about half air and half liquid so each air lift has 38 GPM or 5 CFM air running it. Total air demand (static plus friction) is somewhere around 120 in. H2O plus say another 30 inches H2O for a total pressure to operate of 150 inches H2O. And an air flow rate demand of 4 X 5 CFM or 20 CFM. Therefore a blower to replace an existing plant air system (going away) would need to be able to deliver somewhere around:

180 inches H2O (6.5 psig or 21.196 psia)
24 CFM

(with a 1.20 contingency factor)

Do these figures and logic appear correct? And if a blower capable or producing say 180 inches H2O and 150 CFM was selected and chocked how would it react and operate?

Thanks!

 

[bimr]

You might consider as an alternative, an electrically powered pump as it will be much more economical to operate.