14 replies to this topic

[process16]

hello

i need to know the viscosity of a crude oil with a specific gravity of 0.760 in a diff temperatures

we  dont have  a lab  to do TBP  test  so i need a  graph of estimation

does any one  have  an idea??

 

Edited by tarek12, 04 April 2015 - 07:52 AM.

[P.K.Rao]

For knowing viscosity, you don't have to do TBP. Just do viscosity at any temperature and density at any temperature. Come back to me with this data. I will give approximte viscosities of the same material from 40 to 100 deg C. 

[process16]

For knowing viscosity, you don't have to do TBP. Just do viscosity at any temperature and density at any temperature. Come back to me with this data. I will give approximte viscosities of the same material from 40 to 100 deg C. 

this is the  prob  we  dont have the TBP, all what do we know is the specific gravity

i  dont know if there is an estimating  or no?

[marchem]

as said P.K.Rao to obtain an accurate estimate you should start from some measured value for viscosity,

API TDB includes some methods as for example Abbot et Al. which allows to estimate kinematic viscosity from API gravity and Watson characterization factor, there are also other methods which you may consider depending from data available

[PingPong]

Oil with a specific gravity of 0.760 (55 API) is normally called a condensate, not a crude oil.

 

But that does not really matter, because, just as crude oils, condensates have a name.

With that name you should be able to find all properties of the stuff.

[P.K.Rao]

Yes. UOP 375 gives UOP K (Watson Charecteriztion Factors) from Viscosity and API Gravity. But they are applicable to petroleum distillates. Please see the scope of the method:

 

"This method is for calculating the UOP Characterization Factor of petroleum oils from API gravity and

distillation or viscosity data. Average molecular weight of petroleum oils is estimated from API gravity and

distillation data. The UOP Characterization Factor, commonly called K, is indicative of the general origin

and nature of a petroleum stock. Values of 12.5 or higher indicate a material predominantly paraffinic in

nature. Highly aromatic materials have characterization factors of 10.0 or less."

 

For calculating UOP K, ASTM D 86 or ASTM D 1160 distilaation values are required. These methods are not applicable to crude oils. I will calculate and give by separate method which I developed but yet to publish.

[process16]

Oil with a specific gravity of 0.760 (55 API) is normally called a condensate, not a crude oil.

 

But that does not really matter, because, just as crude oils, condensates have a name.

With that name you should be able to find all properties of the stuff.

its an algerian crude oil, this is why the specific  gravity is low

[Napo]

Dear Tarek12,

 

You can do an estimation by means some correlations, but you need to take precautions.

 

I send you information. I hope help you.

 

Your crude oil is very light, 54.7 °API (= 0,76 SG), Whats is the crude oil name?.

 

Regards,

 

Napo.

Attached Files

•  Crude viscosity.pdf   579.48KB   79 downloads
•  Crude viscosity 2.pdf   524.91KB   62 downloads

[process16]

well thank  you freinds , for whom asked about the crude  oil 

its  an algerian crude  oil  with a  specifique  gravity  of 0.760 at 20°c as  i said  befor

i wanna do a  tubulair  heat exchanger  calculation , this is why iam asking about  viscosity

well i got  a file about Kuop of the  crude  oil

Kuop =12

 

So how  we can get viscosity?

about thermal conductivity is  there an idea to get prcise  value  or i can  use  just general chart????

thank u!!!

Edited by tarek12, 05 April 2015 - 08:37 AM.

[P.K.Rao]

If you have got KUOP, it is fine. Use UOP 375 method. Caculate API gravity. From K UOP and API Gravity, and the profiles given in UOP 375, you can get Viscosities at 100 deg F, 122 deg F and 210 deg F. From any of these two viscosities, calculate viscosity at any other  desired temperature using the viscosity-temperature relation,

loglog(V) = A + B*log(T). T is the absolute temperature degrees Kelvin or degrees Rankine and V is the viscosity at temperature T (cSt or SUS)

or use ASTM D 341

 

A and B are constants

Edited by P.K.Rao, 08 April 2015 - 09:53 PM.

[PingPong]

its  an algerian crude  oil  with a  specifique  gravity  of 0.760 at 20°c as  i said  befor

The name of the country is not the same as the name of the crude oil.

I know Algerian Condensate (~65 API) and Saharan Blend (~45 API) but I never saw an Algerian crude oil or condensate of 55 API.

 

Moreover a K-UOP of 12 is very low for a crude oil or condensate of 55 API.

[JMW]

PK Rao refers to the ASTM D341 viscosity temperature equation. There is a spreadsheet for this calculation here: http://www.cheresour...wnloads&mid=987

[Chellani]

Crude assay is the most reliable source for viscosity. I know that there are few (rather a lot of) correlations available but none of them is reliable. Few process simulators are also using these correlations but users always have problem when they don't provide viscosity of cuts in the crude assays.

[PingPong]

Crude assay is the most reliable source for viscosity. I know that there are few (rather a lot of) correlations available but none of them is reliable. Few process simulators are also using these correlations but users always have problem when they don't provide viscosity of cuts in the crude assays.

I fully agree with you.

[titim]

i from algeria, and i work in a refinery, an algerian crude with 0,76 SG??? it's a condensate note a crude 'sahara blend