8 replies to this topic

[Ebrahim]

Dear all:

I am new here and I am glad that I found this site.
For a pipe line pressure drop determination in hisys
I need to estimate C6+ cut of crude oil properties. (Tc,Pc,Vc,acentricity).
Any advice will be very much appreciated.
For estimating other properties also i need at least 2 from 3 properties:
molecular weight.
Normal boiling point.
Ideal liquid density.
Best Regards for all.

Ebrahim

[Hamid]

Dear Ebrahim,

The easiest way for you is that you can consider a 2 or 3 heavier component as the source of your calculations. For example you may take C8 or C9 properties.Unless otherwise you should define a lube cut.

[Ebrahim]

Dear hamid

but new problem is: " properties or too deep for C7 and C8 ..."
much deeper for light and heavier for example
Tb (c7) =98 c and Tb (c10) = 174 c. (about 75 percents deviation!)
Another problem is complexity of this cut. (C7 to C20 and higher also metals, salts, etc)
I think a good estimate is by experience in this case.

[mbeychok]

Musavi:

We need more information. What is flowing in the pipeline? Is it a gas? How much C6+ does it have? What is the temperature?

For example, if the pipeline is carrying natural gas, the C6+ it contains is probably very little and it probably goes no further than perhaps C8.

As another example, if the pipeline is carrying associated gas (i.e., gas separated from raw, produced crude oil), then the C6+ it contains will probably be more than would be present in a natural gas. Also, the C6+ probably extends somewhat further than C8.

In any event, if the pipeline is carrying a gas, then it is quite improbable that it contains anything heavier than C9 or C10 unless the gas temperature entering the pipeline is very high and the pipeline is heated to maintain that temperature ... all of which I seriously doubt.

[Ebrahim]

mbeychok:

Operating :
Pressure : 74 barg
Max : 109 barg
Temperature : 25 C

Composition (% mole)

H2O : 1.2945
N2 : 3.3198
CO2 : 1.7483
H2S : 0.5303
C1 : 81.2961
C2 : 5.1958
C3 : 1.9251
iC4 : 0.4125
nC4 : 0.6974
iC5 : 0.2849
nC5 : 0.2849
C6 + : 2.5242

[mbeychok]

Musavi:

Thanks for the additional information. At that pressure (75barg) and temperature (25 °C), I am surprised that there is any C6+ still present in the gas phase. Perhaps it was present as entrained liquid ... could that be? In any event, I don't think that your C6+ would extend beyond perhaps C7.

I don't know what accuracy you require, but I should think you could just use the properties of a mixture of nC6 and nC7.

[Ebrahim]

Dear Milton Beychok


Thanks very mush for your responses.

[Vicky Motwani]

Dear sir,

we are facing a problem of liquid entrained with gas: typical properties of the gas are

C1 : 80.27, C2: 7.33, C3: 4.09, iC4: 0.77, nC4: 0.89, iC5: 0.22, nC5: 0.16, C6+ :(varies between 0.16 to 0.86 %) inlet pr is 64 kg/cm2, temp range 23-30 C.
Its a sample from inlet KOD of Gas sweetening unit and the source is from slug catcher where gas comes from offshore as gas + associated condensate.

I have few problems. can this composion gives any idea of entrainment in slug catcher ?

if yes wat could be the possible reason ?

I have seen liquid(more like NGL) while draining inlet KOD.

I also want to calculate my cricondentherm of inlet composion but what to do with C6+ ??
I am using hysis for it .

Please help

[marchem]

for cricondentherm calc's there is specific software including utilities to characterize C6+,
you may read the document in this page

http://www.prode.com...hydrocarbon.htm

if you calculate a phase envelope with full composition (including very low amounts of heavy components) you'll get values of dew points not comparable with measured values as the software is very sensible to these small amounts, there are different procedures to filter composition, selection requries knowledge of the matter or specific tests (i.e. comparing calculated results against measured data), you may contact the software developer.