I am trying to calculate massflow (
I am trying to calculate massflow (
(OP)
I am trying to calculate massflow (of ethane)from our supplier.
They measure this flow using coriolis massflow meter.
However the Reference Gravity used for their calculation(in DCS control logic) is not same as we use on our end.Our Reference Gravity is about 10% lower to their RG.
What difference can this make ?
They measure this flow using coriolis massflow meter.
However the Reference Gravity used for their calculation(in DCS control logic) is not same as we use on our end.Our Reference Gravity is about 10% lower to their RG.
What difference can this make ?





RE: I am trying to calculate massflow (
Good luck,
Latexman
RE: I am trying to calculate massflow (
Sorry!
Good luck,
Latexman
RE: I am trying to calculate massflow (
None the less, one should never disregard any anomaly.
10% is a big difference and presumably the reference gravity has some significance somewhere or it would not be reported by both parties.
So the questions are:
- do you need standard volume?
- what is the significance of reference gravity?
- why do the values differ?
- how does each party determine the reference gravity?
- what is the standard that defines how it should be determined?
If you don't need it in any way then have it removed from both parties records as it is obviously only going to cause ongoing confusion.JMW
www.ViscoAnalyser.com
RE: I am trying to calculate massflow (
The coriolis meters measures density at flowing conditions ie under pressure. Because you are above the criticle point when measureing, the ethane has a high compressibility. So, the density at flowing is going to be more dense that at standard conditions.
The gospal for ethane measurement standards is the GPA publications GPA2154-03. It list pure ethane as having a density of 2.9716 lb/gallon. Your contract may stipulate this density or even adjust for the 1.5% methane and .5% propane in the mixture.