Emerson Exchange 365

• Not Answered

Precision Gas Measurement with Coriolis Mass Flow Meter.

Coriolis Mass flow meter is well know flow technology for fluids measurement ...  but I'd like post a new topic to be open discussed- What is dfference between gas measurement and liquid measurement ? is there any  Coriolis's advantage on Gas measurement opposed other flow technologies ? Why?

Major Chu

• Precision Gas Measurement

Major Chu

• 16 Feb 2012 11:06 AM
• Cancel

5 Replies

• BillGraber

  

  • 16 Feb 2012 11:16 AM

  Not sure I know the entire answer on this - but part of it may be related to the fact that Gas flow has a lower density - so the mass flow is typically less.  Direct Mass would still have advantages in Gas flows being measured in mass or Base Volumetric unts (like SCFH or NM3/Hr) - but the accuracy of the meter will not be as high as liquid.

  • Cancel
• Naimish Raval

  

  • 29 Feb 2012 10:46 PM

  In reply to BillGraber:

  Coriolis  works gr8 for Gas measurement (with AGA 11 compliant), as it has lesser dependence on P & T (AGA 8 super comprisibility). This is gr8 solution for all NG applications (Except cross country pipeline)...  Few distinction POV (Point of View) picth :

  1. Nearly as accuate as online Ultrasonic (even without Wet Cal)

  2. It is very compact, simplified installation with smaller skid footprint & lesser TCO.

  3. Economic SG analyzer - 3098 will get easy transition from mass to volume (Doesn't required online GC)

  AND lastly, it doesn't bring higher pressure drop, nor expensive and available up to 16" process connection. Questions?  

  • Cancel
• Caracas27

  

  • 18 Nov 2015 1:58 PM

  Hi, Major Chu
  
  1.- What is dfference between gas measurement and liquid measurement ?
  - the difference betwen gas and liquid its basicly about properties of the flowing, for example, the Compresibility Factor, it is most dificult know the density of a gas than a liquid, in fact is necesary a norm for calculate the compresiblity factor (AGA 8).
  There are more differences , but for me, this is the most important
  
  2.-with respect to the benefits of Coriolis .
  - I agree with Naimish Raval , you'll also find lots of information in the pages of the manufacturers ( endress , Emerson , FMC , etc )

  • Cancel
• Marc Buttler

  

  • 18 Nov 2015 3:59 PM

  In reply to Caracas27:

  Hi Carlos Ramos.
  
  The biggest difference between gas and liquid measurement definitely has to do with the compressibility. Many liquid measurements can and are still done on an actual volume basis because liquids are much less compressible than gases and the volume at reference conditions can usually be determined easily from the actual volume measured with a simple temperature correction (and sometimes a small pressure correction). Gas measurements, on the other hand, must almost always be corrected to standard volume at reference conditions using AGA 8 calculations and pressure and temperature measurements. Actual volume measurement of a gas is almost entirely useless because it will change so much as pressure and temperature change. You need to also worry that the pressure and temperature measurements you are using to convert an actual volume measurement of gas into standard volume might be different at the pressure and temperature sensors than it was in the flow meter where the flow was measured.
  
  Coriolis meters are great for measuring both gases and liquids because they can measure both mass directly and volume at the same time. So, with a Coriolis meter, you can measure liquid in both mass and volume at the same time, depending on your need, and you can measure gas in mass and standard volume very easily without the need for any pressure or temperature measurement. This is possible because the mass and standard volume are related to each other by the base density (the density of the gas at reference conditions) and nothing else. This is shown in AGA 11 equation D.2 (standard volume = mass / base density). Because the base density is defined as the density at reference conditions and not at actual conditions, it never changes as temperature and pressure change. It will only change if the composition of the gas mixture changes.

  • Cancel
• Caracas27

  

  • 18 Nov 2015 4:48 PM

  In reply to Marc Buttler:

  Hi Marc
  
  thanks for your coment, its very interesting

  • Cancel