6 replies to this topic

[Gaston_Engineer]

Hello Everybody

 

I am designing a three-phase separator. I am following the Monnery and Svrcerk method. 

 

The only thing I have trouble is with the formula attached,

 

The residence time is used to check the diameter selected of the boot. I think that there is a typing mistake, I belive that it should say  D_B instead of D_p (Particle diameter). 

 

I have done the calculations and my assumtion seems to be right, because the size of a drop (particle) it is in the range on microns. 

 

Could somebody tell me if it is OK, please?

 

Thanks in advance

 

Gaston.

[breizh]

Hi,

Consider the article attached to support your work.

Yes it's Db , see the document ,highlighted in yellow.

Breizh

[Bobby Strain]

Is this an academic exercise? The minimum boot diameter is indeed determined by the light phase rising velocity and the heavy phase flow. And you will get a greatly oversized separator using this old method. One would never design with this method for a real application. It's for an academic exercise. You can visit my website where you will find a sample that is pretty good. And another free application that will size the boot in a liquid settler. The best design software is by subscription.

 

Bobby

[Pilesar]

Bobby, you mentioned before how the published separator design guides give oversize. Can you explain further? A dozen years ago or so I compared eight to twelve separator design methods from the sources I could find. I ended up putting the ones that seemed most reasonable and complete into spreadsheet. So my designs are tweaked until all or most of the methods are satisfied or where they are not satisfied, I come up with an explanation for myself. Usually the GPSA method I consider most reliable. I have designed separators as engineer with E&C and with owner companies using this procedure. I admit my separator designs are conservative -- that is my goal -- but they are also defensible using 'industry standard' published methods. Are they too big? Probably. I do see existing separators that are much smaller than I would make them which operate with no complaints and I cannot explain why they work. But my conscience demands I have engineering principles and a basis for my designs. That demand would not be satisfied by a 'black box' subscription software that I could not replicate by hand calcs. I hope your business is very successful and I am not trying to talk anyone out of using your software. Would you please elaborate on the basis for your separator designs?

[Bobby Strain]

Pilesar,

       Register at my site and I will give you access to the program. Let me know when you register. And, to make your experience best, read the help. You can communicate with me via the email you find on the login page.

 

Bobby

[Gaston_Engineer]

Hello 

 

Breiz / Bobby Strain / Pilesar

 

First, I want to thank you all for your responses. 

 

Breiz:

 

Thank you very much for your explanation and for the article. That was very clarifying to me.

The version of the article that I have, has many printing errors.  

 

 

Bobby;

 

Tahnk you for answer me. 

This is not an academic exercice, I needed just for giving a preliminary design in order to have an idea about the size of the equipment. It's very likely that my design is a bit oversize.

 

I know there is a lot of software for sizing different process equipment, but right now I can not afford any of them. However, I will visit your website.

 

 

Pilesar:

 

Thank you for your comments. I have already checked the GPSA, and I got some ideas. 

 

 

Gaston

[Bobby Strain]

Gaston,

    If you will send the sizing parameters to the email at my site, or post them here, I'll check your results when you have them. Also, for you and Pilesar, once you register, you can download a few useful libraries and spreadsheets and applications.

 

Bobby