19 replies to this topic

[BabRafiq1]

Dear members,

I'm designing a 3phase separator but unable to find information about ID calculation nozzles for gas and liquids. Any one can recommend any book, article or any thing of help.

Thanx,  

[breizh]

Hi,

Consider to study this resource .

Good luck

Breizh 

[Chemitofreak]

The mixed stream and gas outlet nozzles are sized based on Rho*V2 criteria. For liquid outlet use the velocity criteria 

[breizh]

Hi,

To add to my previous reply consider the resource  attached.

https://www.red-bag....sel-sizing.html

 

Breizh

[Bobby Strain]

There is an error in the red-bag guide. The units are not SI but US units. Density is in lb/ft³ and velocity is ft/sec.

 

Bobby

Attached Files

•  Nozzles.pdf   34.93KB   113 downloads

Edited by Bobby Strain, 28 August 2022 - 11:41 AM.

[breizh]

Hi,

Another reference , pay attention to the units system :

https://petrowiki.sp...eparator_sizing

 

Breizh 

[james.corrobro@gmail.com]

INLET NOZZLE SIZING 

 

If no inlet device is used: 

ρ_mv²_m,in ≤ 1000 Pa 

 

where ρ_m is the mean density of the mixture in the feed pipe 

ρ_m = (Q_lρ_l + Q_hρ_h + Q_Gρ_G)/(Q_l + Q_h + Q_G) 

 

and v_m,in is the velocity of the mixture in the inlet nozzle 

 

v_m,in = (Q_l + Q_h + Q_G)/(π d₁² / 4) 

 

If a half-open pipe is used as inlet device: 

ρ_mv2_m,in ≤ 1500 Pa 

 

If a Schoepentoeter is used as inlet device: 

ρ_mv²_m,in ≤ 6000 Pa 

 

 

GAS OUTLET NOZZLE SIZING

 

The diameter of the gas outlet nozzle should normally be taken as equal to that of the outlet 

pipe, but also the following criterion shall be satisfied: 

 

ρ_Gv²_G,out ≤ 3750 Pa

 

LIQUID OUTLET NOZZLES 

 

The diameter of the liquid outlet nozzles shall be chosen such that the liquid velocity does 

not exceed 1 m/s. The minimum diameter is 50 mm (or 2 inch). 

 

Above criteria are from Shell DEP 

[james.corrobro@gmail.com]

Inlet nozzle velocity

It is a common practice to design the inlet nozzle based on the momentum (ρv²) of the entering fluid. The nozzle size depends on the presence of internals in the inlet nozzle.

The following guidelines are often used to size the inlet nozzle:

 

 (ρv²)_max inlet nozzle: no inlet device ≤ 1000 kg/ms²

 half-open pipe inlet ≤ 1500 kg/ms²

 

Gas outlet nozzle velocity

As the gas outlet nozzle is not required to be designed for a two-phase flow, a higher momentum can be used for the design.

Normally, the following value is used:

 (ρv²)_max gas outlet nozzle: ≤3600 kg/ms²

 

Liquid outlet velocity

Liquid outlet nozzles are generally designed based on the liquid superficial velocity of 1 m/s.

[Bobby Strain]

Shell has issued many updates over the years. And the criteria change. It would help if you also provide the year of the Shell Dep issue.

 

Bobby

[james.corrobro@gmail.com]

2007 Edition

[Bobby Strain]

I have both the 2004 and 2008 editions and both have the same values. But the values are not the ones you posted. The values are greater in both these editions. I note that the red-bag guide has the same values that you posted. I wonder where they all came from.

 

Bobby

[breizh]

Hi Bobby,

extract from my edition January 2008 .

Breizh 

[james.corrobro@gmail.com]

There are several criteria available in different references including Shell DEP, GPSA and books for nozzle sizing. 

I'd rather use a slightly stringent criteria for nozzle sizes. 

 

Additional References:

GPSA Section 7:

 

It  is  also  necessary  to  maintain  the  inlet  velocity  head,  J,  within proper limits for the selected inlet device to insure good gas distribution and minimum liquid shattering.

Where,J   =  (ρV²)

The maximum mixed phase velocity head range used in the industry guidelines varies for the different inlet devices. Some typical maximums are

4000-6000 max. typ, up to 10,000 max lb/ft sec² for diffuser distributor

650-1500 max lb/ft sec² for no inlet distributor

1000-2500 max lb/ft sec² for inlet half pipe or elbow distributor

1000-2500 max lb/ft sec² for v-baffle or other simple inlet diverter designs

In addition, some users limit the inlet vapor phase velocity to 30 ft/s or 60 ft/s. The velocity should always be below the erosion velocity for the service

 

 

 

From: Bahadori, A. (2014). Natural Gas Processing: Technology and Engineering Design. Netherlands: Elsevier Science.

 

See attached

 

 

Attached Files

•  ref.pdf   294.16KB   41 downloads

[james.corrobro@gmail.com]

Thanks for pointing it out. I think I have an old version of DEP.

 

Don't know what you mean by red bag guide

 

There are several criteria available in different references for nozzle sizing. As long as these are properly referenced in a calculation and the basis is made clear, there should not be any issues. 

 

 

I have both the 2004 and 2008 editions and both have the same values. But the values are not the ones you posted. The values are greater in both these editions. I note that the red-bag guide has the same values that you posted. I wonder where they all came from.

 

Bobby

[Bobby Strain]

You can find the Red-Bag guide in the links at my website. While you are there, use the sample horizontal separator design program. The link is in the text body at the home page. It's probably better than anything you have used.

 

Bobby

Edited by Bobby Strain, 15 September 2022 - 12:47 PM.

[james.corrobro@gmail.com]

Thanks, I will check it out

 

 

You can find the Red-Bag guide in the links at my website. While you are there, use the sample horizontal separator design program. The link is in the text body at the home page. It's probably better than anything you have used.

 

Bobby

[james.corrobro@gmail.com]

@bobby - what is the criteria for de-rating of K used in your website calculations?

 

I am trying to see GPSA and another reference but don't get the same value as your website

 

You can find the Red-Bag guide in the links at my website. While you are there, use the sample horizontal separator design program. The link is in the text body at the home page. It's probably better than anything you have used.

 

Bobby

 

Attached Files

•  snapshot1.JPG   72.54KB   4 downloads

[Bobby Strain]

I think what I use are the original factors from York. The demister is high capacity wire mesh here.

Pcorr = 1
            K1 = 0.42
            If PressOp > 35 Then _
                Pcorr = 1 - 0.17 * System.Math.Log10(PressOp / 35)
            If PressOp < 15 Then _
                Pcorr = 1 + 0.45 * System.Math.Log10(PressOp / 15)
            K1 = K1 * Pcorr
            mesharea = CFSV / (K1 * SepFactor)  'area in sq. ft.

 

You missed the horizontal separator sample. It's not in the menu, but a link in the home page text.

http://www.bobby-str...lSeparator.aspx

 

Bobby

Edited by Bobby Strain, 15 September 2022 - 04:15 PM.

[james.corrobro@gmail.com]

Thanks, Bobby

I think what I use are the original factors from York. The demister is high capacity wire mesh here.

Pcorr = 1
            K1 = 0.42
            If PressOp > 35 Then _
                Pcorr = 1 - 0.17 * System.Math.Log10(PressOp / 35)
            If PressOp < 15 Then _
                Pcorr = 1 + 0.45 * System.Math.Log10(PressOp / 15)
            K1 = K1 * Pcorr
            mesharea = CFSV / (K1 * SepFactor)  'area in sq. ft.

 

You missed the horizontal separator sample. It's not in the menu, but a link in the home page text.

http://www.bobby-str...lSeparator.aspx

 

Bobby

[Bobby Strain]

You can now access the sample separator from the menu. You don't need to register or login.

 

Bobby