12 replies to this topic

[Ali4269278331]

hello to everyone

i need to help about pipe segment in Aspen Hysys.

segment.1: 6in, 2bar.45oC.sch 40(STD).carbon steel. milled. 70mt

segment. 2:16in, 0.09bar. 42oC. sch40STD).carbon steel. milled. 10mt in horizontal + 4mt in vertical orientation

fluid:crudeoil(intermediate or heavy component are too much) with a little bit gas. C1.C2.C3.C4.C5.C6.C7.C8.C9.C10.C11.C12+

heat loss:3oC

 

my calculation with Hysys was 0.47 bar. if possible for any guys, please check it.

 

thanks

[Pilesar]

Hysys usually does a decent job of calculation. Why do you need Hysys checked? It is probably the input that needs checking! My back-of-the-envelope calculation: Friction pressure drop in the second segment will be 2 bar times the ratio of the diameters to the fourth power multiplied by the ratio of the lengths. (6/16) to power of 4 multiplied by (14/70) * 2 = 0.008 bar. Add the pressure drop due to elevation change. I don't know what 'mt' units of measure means so that is my best guess for a rough check. Check that the vertical segment is input correctly into Hysys if the difference is due to elevation change.

[shvet1]

What does "mt' stand for?

Edited by shvet1, 17 October 2024 - 11:55 PM.

[breizh]

Hi,

Probably meter !

Breizh

[shvet1]

if so then 

 

my calculation with Hysys was 0.47 bar. if possible for any guys, please check it. 

 

checked

dP can be 0.047, 4.70 or 47.00 bar depending on design flowrate and actual vapor fraction (do not confuse with gas content).

[katmar]

Pilesar is absolutely correct - the pressure drop calculation is a trivial matter and it is the input that is important. Does Hysys allow you to enter the composition as "a little bit of gas"? If there is any error it will be in the determination of the density and viscosity of the fluid, and you have not given nearly enough information to check those values. Nor have you given the values that Hysys reported for the density and viscosity.

Giving us some clues on what the flow rate is would also be helpful if you want the pressure drop checked.

[breizh]

Hi,

Katmar , Pilesar and Shvet1 came with good points. Without any process information, how can we support you? 

 

Share at least , flow rate, composition , viscosity, density  of the 2 phases ( liquid/gas) , surface tension .

We have to understand that the temp expressed in Celsius are 45 and 42 C.

 

A sketch could help. Not clear your data about pressure, confirm the location, values and unit (absolute or effective)

 

Note:

For those using the same software you should provide your input file.

 

A long way to go. Let you study the documents attached .

Breizh 

Attached Files

•  Pressure Drop 2 phases flow.pdf   713.46KB   6 downloads
•  2 phase flow.xls   128KB   9 downloads

[shvet1]

@Ali

What for do you model crude oil hydraulic? Where this pipe is (will be) located? Which ind sector is it: up/mid/downstream?

 

@katmar

the pressure drop calculation is a trivial matter 

A controversial point regarding 2-phase models which OP's case has a potention to be.

Not not touching phase equilibrium, even the transport properties of hydrocarbons are a challenging issue, for this reason SimSci (Pro/II, Pipephase) have developed propriate hydrocarbons transport properties correlations.

 

a user takes +/-15% accuracy of a some liquid hydraulic model (Fanning, Crane, Darcy, Idelchik etc.)

multiply +/-30% accuracy of field input data (incorrect specification, future expansion etc.)

multiply +/-30% accuracy of rougness deterioration and actual local resistances vs modelled

multiply +/-20% accuracy of assumptions of liquid vs 2/3-phase fluid behaviour

mulitply +/-15% accuracry of phase equiplibrium and properties models (Peng-Robinson, API TDB, Lee-Kesler etc.)

and on top of all this multiply +/-500% accuracy of vaporization rate vs predicted pressure drop

and what does one get in result?

Edited by shvet1, 18 October 2024 - 07:00 AM.

[katmar]

@shvet1 - perhaps it was a bit too strong for me to call it trivial but what I was getting at was that the mechanical calculation of the pressure drop once the OP has the input data is the easy part and that was all that the OP seemed to be asking for.

 

If you look at the list that you have made of potential errors they are virtually all what I would call input data and not the actual calculation.  These were the sort of information that I was implying that the OP should provide.  Once you have all that information cranking the handle on the calculator is close to trivial.

 

But you have expressed it far better than I did, so hopefully the message has got through.

[Ali4269278331]

What does "mt' stand for?

mt is abbreviation for meter.

[Ali4269278331]

Hi,

Katmar , Pilesar and Shvet1 came with good points. Without any process information, how can we support you? 

 

Share at least , flow rate, composition , viscosity, density  of the 2 phases ( liquid/gas) , surface tension .

We have to understand that the temp expressed in Celsius are 45 and 42 C.

 

A sketch could help. Not clear your data about pressure, confirm the location, values and unit (absolute or effective)

 

Note:

For those using the same software you should provide your input file.

 

A long way to go. Let you study the documents attached .

Breizh 

thanks dear Breizh

So, i have just pressure, temp, pipe size, distance,sch, pipe material, phase composition. your excel file was very good.i will try to send simulation model.

[Ali4269278331]

Pilesar is absolutely correct - the pressure drop calculation is a trivial matter and it is the input that is important. Does Hysys allow you to enter the composition as "a little bit of gas"? If there is any error it will be in the determination of the density and viscosity of the fluid, and you have not given nearly enough information to check those values. Nor have you given the values that Hysys reported for the density and viscosity.

Giving us some clues on what the flow rate is would also be helpful if you want the pressure drop checked.

dear Katmar, your idea are correct. but i donot have many PVT data. i work in operation field. 

 

Pilesar is absolutely correct - the pressure drop calculation is a trivial matter and it is the input that is important. Does Hysys allow you to enter the composition as "a little bit of gas"? If there is any error it will be in the determination of the density and viscosity of the fluid, and you have not given nearly enough information to check those values. Nor have you given the values that Hysys reported for the density and viscosity.

Giving us some clues on what the flow rate is would also be helpful if you want the pressure drop checked.

[shvet1]

 

mt is abbreviation for meter.

 

 

Why "mt"? Why not "me" or "mr"?

 

 

 

So, i have just pressure, temp, pipe size, distance,sch, pipe material, phase composition. 

 

my calculation with Hysys was 0.47 bar.

 

 

You have a Hysys model which gave you 0.47 bar. Can you please share with us how you have obtained it not knowing the flowrate?

And where from have you got the pressure?

Edited by shvet1, 21 October 2024 - 12:24 AM.