34 replies to this topic

[Neelakantan]

@processengbd

 

an off-side question; fear I may be panned by other for this!

you said you are an iso certified company with a good engineering team; what are the internal comments on the question?

 

regards

neelakantan

[pallavikhatri]

Dear All

I have a query related to the type of three phase separator that is to be selected.

As specified in Shell DEP, "a three phase separator with a boot is selected when the vol. flowrate of heavier phase is less than 5% of the inlet flow and de-oiling of the heavy phase is not critical" while for " a separator with a weir arrangement is used where the IL is ill defined and the de-oiling of heavy phase is required."

My query is,

 

1) How can we define that the interface is well defined or ill-defined.

 

2) I have a three phase feed where my heavy phase flow is less than 5% and the deoiling of the heavy phase is also required. So in this case what type of separator should i select- three phase separator with a boot or with a weir arrangement? Also pls suggest whether  a three phase settler with a boot can also have a weir plate at the end?

 

Regards

Pallavi

Edited by pallavikhatri, 09 June 2014 - 12:50 PM.

[Bobby Strain]

We might be able to help if you tell us what the fluid is.

 

Bobby

[pallavikhatri]

The fluid is water, oil and gases rich in C1 to C4. Basically this is the condensate stream at the outlet of a slug catcher which is going to a flash drum to recover the gases.

 

Regards

Pallavi

[Neelakantan]

the idea of using a boot is to provide a 'height for de-hydrocarbonating" of heavier phase assume gravity settling is effective. you can have a bigger vessel dia to provide the same height for the heavy phase or provide a leg/boot.

 

in your case, if the condensate is not emulsive (based on the chemicals u/s), you can use a vessel with weir and boot

 

regards

neelakantan

 

PS:

1) why you use shell DP? client is specifying?

2) what are the client process spec/ design basis?

Edited by Neelakantan, 10 June 2014 - 01:52 AM.

[pallavikhatri]

Dear Neelankantan

Thanks for your reply.

 

Yes the fluid in my case is not emulsive. In my case the quantity of the heavy fluid is less than 5% so in this case a boot is sufficient. Then what is the use of providing a weir in the separator since the L/L interface will be formed inside the boot if I am not wrong?

 

Regards

Pallavi

[Neelakantan]

weir side is for L/G interphase level control; vessel side will have fixed level (overflow level)

http://www.enggcyclo...uid-separation/

 

regards

neelakantan

[pallavikhatri]

Thanks for sharing this link but still it is not clear from the link that how providing a boot will enhance the separation.

 

Regards

Pallavi

[Bobby Strain]

Sounds like you need to review the fundamentals of liquid-liquid separation. And the phase behavior in three-phase separators.

 

Bobby

[Neelakantan]

@palllavi,

submit your calculations of the three phase separator without boot but with a weir only; then me or more knowledgeable members can help you to see how size (dia) may reduce if you use a boot!

 

regards

neelakantan