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Posted by Anonymous on March 12, 2001 at 07:54:54:
Can anybody share her/his experience of using on line indirect methods (
NIR/NMR or other) for measurement of petroleum fraction properties? These
methods are used as replacement for the on line analyzers that are measuring,
for example, X% distillation point, freezing point, cloud point etc.
I'm interested especially in the behavior of these methods during feed
composition changes. E.g.: measurement of atmospheric crude column products
during a crude switch. Are the measurements consistent with the lab? As the
indirect methods are usually based on chemical composition/molecular structure
statistics sometimes the measurements may change quite drastically while the
lab results do not.
To put it in other words:
Have you used an NIR/NMR that A) Can handle any feed/stream composition even
for molecular composition not processed in the unit during commission.
B) Is accurate enough for your purpose.
It will be very helpful if the person who responds will write here some data
regarding the performance of these methods.
E.g.: NIR/NMR reproducibility compared to the ASTM reproducibility, the existence
of bias when comparing against lab results, the bias Vs feed/stream composition
and any information which the reader thinks is helpful.
Thanks