4 replies to this topic

[rasprocess]

Hi

I have designed a 3 phase separator for separation of vapor, hydrocarbon liquid and water. more than of 20% weight entering liquid to drum is water, therefore baffle must be used instead of boot. i calculated diameter and height of drum correctly, but i dont know how to calculate the location of vertical buffle in drum.
I would appreciate u if u give me some help.

[Bobby Strain]

If you don't know where to locate the baffle, how are you sure that you have properly sized the drum?

Bobby

[rasprocess]

Hi

diameter and length of drum is calculated and has negligible deviation from data mentioned in datasheet. but baffle location ( baffle distance from the end of drum ) is not correct.

[Fr3dd]

Dear rasprocess,

I think you may be a little bit confused here. for this calculation, you need to imagine that the vessel is divided in three parts:
1- The section where the separation is performed.
2- The section where the light liquid is "stored" for pumping
3- The section where the heavy liquid is "stored" for pumping

Depending on the configuration chosen (bucket & weir, or submerged weir), the calculation of the vessel dimensions may vary a little bit. All of this calculation are based on the time needed for the liquid droplets to settle according to stokes law. This will help you determine the diameter and lenght of the separation section. There are some rules of thumb regarding the baffle height and the interphase height that will help you with baffle sizing. After all this is done, you will determine the size of your weirs (section 2 and 3) based on the light and heavy liquid expected flowrate and the holdup time you need for your specific application.

I think the latter is what will give you the position of the baffle from the end of drum. If you obtained the same dimensions on your calculations but did not considered all the factors I mentioned, you may need to double check your calculations. The baffle is like the "second step" in the three-step calculation of your vessel.

Regards,

Edited by Fr3dd, 05 November 2012 - 09:39 AM.

[Bobby Strain]

If you give us information on the separator and fluids, maybe we can be helpful.

Bobby