Gas Cyclone Efficiency

[Fusin]

I'm looking for some correlations to determine cyclone efficiency with cyclone drawing & feed distribution particle sizes.

I read some information about D50. Can I calculate the particule size for other than D50? I would like to be able to traced the partition curve.

Thanks in advance!

 

[siretb]

I am not sure this is what you want.
Sticking to simplicity, the efficiency for a given particle size, of same density, can be given by
Collection efficienct=1./(1.+(d50/d)^beta))
where beta is an exponent, usually between 2 and 3, and often closer to 2. than to 3.
There are numerous formulas relating the efficiency of a cyclone of given geometry. The above formula allows you to have an idea, using a beta of 2.

 

[Fusin]

If I increase the gas flow (I keep the same % of solids and the same distribution size), I suppose than the velocity inside the cyclone will increase and the efficiency will decrease... Am I wrong? I would like to quantify this affirmation.

 

[Fusin]

Does anyone know a way to calculate the number of turns made by gas stream in cyclone?

 

[chief]

You can increase the efficiency of a cyclone separator by fitting a Spiral path to direct the inlet gas flow. Fibonacci ratios seem to work best for the actual cyclone construction. The number of paths can be approximated to the pitch of the inlet spiral.

Offshore Engineering&Design

 

[siretb]

Fusin:
In a gas cyclone, if you increase the flowrate the velocities will increase and so will the efficiency.
However you pay a great price for this: the pressure drop much increases.
For reverse flow gas cyclones, there is no mystery: the collection efficiency is directly linked to the pressure drop.
I know not everyone will agree, but I would say, that for a given particule size distribution, there are no classical designs that will be much better than others.
So if you have particule sizes large enough (say > 10 microns) I would not bother for any special feature and I would not do what chief suggests.
For a given pressure drop, you'll get an efficiency.

Again increasing the flowrate gives a better efficiency
If you need more, please stete your actual PSD (particule size distribution), particule load and flowrate range

 

[MortenA]

The data you are asking for is in my basic unit operation course text book (its a danish book so i wont bother with the reference). I would think its in Perry too or any similar text book.

Best regards

Morten

 

[Fusin]

thanks you all for your comments!

I find what I need in the Perry 7th...
A last question : when i'm calculating the load of solids in m3 of gas (fig. 17-40, Perry, 7th), should I consider standard m3 (60°F & 14.7 psig) or actual m3 (operating conditions)?

 

[siretb]

Actual concentration (grams per actual cubic meter, with no correction whatsoever (O2, wet/dry or so)