5 replies to this topic

[empower70]

n-Hexane + wax mixture is heated with LP steam. The purpose of paddle agitator is mixing and heat transfer.


Details/Data:

Paddle quantity:2

Paddle dia:2.4 meter

Agitator rpm: 25

Vessel ID: 3.32 meter

Baffle quantity: 2

Opearting pressure: 0.2 kg/cm2g

[latexman]

References that speak to mixing are Perry's Handbook (any Edition), Oldshue's Fluid Mixing Technology, Lightnin's A Guide to Fluid Mixing, and Chemineer's reprint from Chemical Engineering Magazine Liquid Agitation.

For design viscosity less than 100 cP, I got 5.3 kW for a pitched blade turbine with 4 blades.

[empower70]

Thanx latexman,
Most conventional references, I guess, give design for single paddle agitator.
Is it ok to multiply power for 2 paddle agitators by 2?

empower70.

[latexman]

Is it ok to multiply power for 2 paddle agitators by 2?

That is the usual practice. It is conservative, but not overly conservative.

[empower70]

Thanx latexman.
In the meantime, i would appreciate, if u could share website/hyperlink for the references u have mentioned, for estimating power for the said application.

Regards,
empower70

[srtools1980y]

hi!
the best reference is '' horsepower tables for agitator impellers,'' l.t.advani, gulf publishing co.
isbn 0-87201-368-5
pity it's out of print. try amazon used books.

Literature cited :-

1. L.T.Advani – Horsepower Tables for Agitator Impellers –
Gulf Publishing Company.1976.
2. Holland F.A. --Chem. Engg.- 69 (19) (1962)
3. McCabe & Smith – Unit Operations of Chem.Engg.-
McGraw Hill.
4. Holland & Chapman – Liquid Mixing in Stirred Tanks –
Van Nostrand Reinhold.
5. Dudley – Gear Handbook – McGraw Hill.
6. Chemineer Inc. – Chem. Engg. Refresher – Liquid Agitation –
Chem. Engg. Magazine – 1975/76.
7. Greaves – Gearbox Ratings & Selection Catalogue.


Note : In literature cited at serial no. 1, the net hp. is in tabular format,
generated on an IBM 1401 computer, using inputs such as impeller
type, impeller dia., liquid SG, viscosity & impeller speed.