Online communities continue to grow and prosper as the capabilities of social sites and software platforms continue to advance. I received an email from a student in France who asked:
I would like information on the products you offer in mass flow measurement for fuel gases. What measuring devices do you have in your product portfolio that would give the following as outputs: mass flow, compressibility factor, isentropic coefficient, maybe also volumetric flow. The measurement device should work within these ranges: piping size 6 to 10 inch massflow 0 to 20 kg/s temperature 0 to 200 degC pressure 0 to 60 bar
I knew that the Micro Motion Online Community would be a good place to post this question and see what guidance members of the community might have. Emerson’s Tom O’Banion, a chemical industry marketing director for the Micro Motion team, posted a great reply. I’ll highlight the main portions from his response [hyperlinks added]:
We have several flow divisions, which offer technologies such as Coriolis, Vortex, dP flow, as well as Turbine and Ultrasonic (the last two through our Daniel division). As well, we have an Analytical division that offers Gas Chromatographs.
Which technology we’d recommend depends on the goals of the application.
I work for the Coriolis division and am very experienced in gas flow measurement.
What we offer is a line of Coriolis meters from around 3 mm to line sizes exceeding 14″ (350 mm). Their accuracy and turndown are a function of flow rate and operating pressure. Generally, with an operating pressure above 30 bar, we can offer a superb turndown of 20:1 or better and typical mass flow accuracies of 0.35% of rate. For specific conditions, a sizing is done, and a unique size meter is chosen. This is similar for Vortex (volume flow) and dP (various primary elements such as orifice plates, venturis, averaging pitot tubes, etc). dP is easier to vary the primary element size, as it fits “inside” the pipe vs. being a meter body.
The flowmeters don’t offer compressibility factor or isentropic coefficient (these require a GC). Coriolis doesn’t need these variables for flow. You may need them for other purposes. Coriolis has these advantages on Fuel Gas:
- Mass flow is not sensitive to composition changes
- Coriolis does not have flow effects from elbows and swirl, so requires no straight run
- Measures mass flow directly, so no PVT corrections
- IF the standard density is known (for Fuel Gas, requires knowledge of the composition) we can configure the mass measurement into a volumetric output (e.g. NM3/hr or scfm)
- Generally very wide useable range
- Ability to handle 60 bar and 200 deg C conditions
Moving this exchange out from the confines of emails into online communities provides the opportunity for the next person with similar questions to discover this thread through search and add his or her perspectives. It’s definitely a communications trend headed in the right direction!