Viscosity Conversion
Viscosity Conversion
(OP)
Hello,
Can some one help me, I would like to have some sort of correlation to convert the heavy petroleum cuts (such as Vacuum bottom) Viscosity @ 100 °C to 50 °C. Any reference that I can refer to? Thank you.
Can some one help me, I would like to have some sort of correlation to convert the heavy petroleum cuts (such as Vacuum bottom) Viscosity @ 100 °C to 50 °C. Any reference that I can refer to? Thank you.





RE: Viscosity Conversion
The typical viscosity of our Vacuum is 2800 cts @ 100 °C, I would like to know the viscosity @ 50 °C. Thank you.
RE: Viscosity Conversion
I haven't got this paper which sounds relevant for your problem
S.A. Beg, M.B. Amin and I. Hussain, "Generalized Kinematic Viscosity - Temperature Correlation for Undefined Petroleum Fractions", The Chemical Engineering Journal, 38, 123-136, 1987.
Perry's Chem.Eng. Handbook includes a section on correlation/prediction of absolute viscosity that might be of use. A generalized viscosity vs temperature chart is presented which, if your viscosity was 2800 centipoise at 100C, would indicate the viscosity at 50C to be approaching 1,000,000 centipoise, so I would check out alternative references.
Regards
RE: Viscosity Conversion
RE: Viscosity Conversion
While some methods may be a bit complex, the correlations are available. Viscosity is pretty difficult to predict with great accuracy though...so I'm not sure if anything will give you what you want for very viscous materials (i.e., atmospheric resid). Someone else may be able to comment on this.
Good luck!
Bob
RE: Viscosity Conversion
The other option is to find plotted vis data for similar fraction. Most similar fractions have similar slopes. Thus, you can use your data point and their slope to extrapolate, I've done this in the past.
As mentioned, if you are getting up into the 1 MM cst range, the accuracy of the results is going to be only so so at the best.
RE: Viscosity Conversion
By plotting a gas oil of the same crude oil origin on log-log paper you'd get a straight line. By drawing a parallel for VB, you probably would estimate the viscosity @ 50 Celsius. To transform back to cS must divide by densities.
Better, as TD2K suggests, use two actually measured kinematic viscosities at two different temperatures and by linear extrapolation on a Refutas type of chart, find the viscosities at other temperatures.
RE: Viscosity Conversion
RE: Viscosity Conversion
I don't know what you need this value for or what accuracy you need. Are you doing a fuel oil blend calculation?
RE: Viscosity Conversion
If you visit www.solartronmobrey.com and follow the bunker fuel link you can download a spreadsheet which allows you to run this equation on any product for which you have the viscosity at two temperatures. You can also download a powerpoint which explains how we use a number of calibration curves to use a single viscosity measurement to find the viscosity at base temperature. Of course, we use this in our viscosity computers for continuous process measurement but you could adapt the spreadsheet to allow you to do this with lab sample data.
However, i suspect you could use a cone and plate viscometer in the lab to measure the viscosity at 50degC (or if it is solid, at two other temps and use the spreadsheet to assess the theoretical viscosity at 50degC. Cone and plate viscometers are supplied by london research equipment (www.london-research.com I think)