Mass Flow Measurement of mixed vapor

[controlnovice]

We have an application where we need the Mass Flow measurement of a mixed vapor. Unfortunately, we don't know the concentration of each of the gases but we know it will can range from 100% N2 to 80%Butadiene, 15%Pentene, and 5% N2.

Looked at Ultrasonic flow (Panametric), but were told the N2 will not work and our velocity is not high enough. We are expecting 0 - 100 lbs/hr of BD max...but again, the composition can change. Max flow is 100lbs/hr, normal flow 8 lbs/hr.

Any suggestions?

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[zdas04]

Find a plan "B" because there is no meter that is ever going to do this.

With a VERY capable computer (say a Cray?) you could put an online GC in the stream and use an orifice meter with a new gas composition input a couple of times a minute. You are not going to find that calculation in a basic RTU, you'll have to write it yourself.

David Simpson, PE
MuleShoe Engineering

"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.

 

[danw2]

What's the maximum medium temperature?
Line size?
What is the N2 velocity that it is "not high enough"?

 

[IRstuff]

Are you looking for a individual species mass flow, or just the aggregate?

a GC sounds plausible:

http://products.baseline-mocon.com/...gas-chromatograph/item-1025?&bc=100|1006|1048

TTFN
faq731-376

 

[roydm]

Perhaps a thermal mass flowmeter will tell you the overall flow but certainly not the percentage of each.

Check the individual gases as though each was 100% of the flow see what it looks like.

Do you have an analyzer that gives the composition?

Line size?

 

[dcasto]

Try here.

http://www2.emersonprocess.com/en-us/brands/micromotion/related-information/pages/measuring-gas.aspx

Or a mass meter like an orifice meter and a gravitometer

http://www.google.com/search?client...measurement&ie=UTF-8&oe=UTF-8&channel=browser

or densitometer.

 

[zdas04]

Micro Motion meters require a fluid analysis as input. They also require more mass flow than this application. Bad choice of technology for this stream.

David Simpson, PE
MuleShoe Engineering

"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.

 

[controlnovice]

We'll have the BTU content of the stream.....if that helps any....

Either from GC (not fast enough response), or Calorimeter....

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This is normally the space where people post something insightful.

 

[hacksaw]

lets see the Cray I supercomputer was really something in the day, but only matched a 486 running at 400 mhz! gee how have things changed, the modern cell phone beats that these days...

 

[zdas04]

Each Cray processor was about an i486, but there were a bunch of them running a massively parallel architecture. I ran a couple of early fluid models on one and it ran the models in seconds with all the data where the mainframes of the time took hours for a subset of the data. It really was a pain to adjust the code to take advantage of that many parallel threads (determining what could be run in parallel and what had to run sequentially and what could run whenever there was a free processor). The Cray I had capabilities that my BlackBerry can't come close to (may I should get an iPhone?).

David Simpson, PE
MuleShoe Engineering

"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.

 

[icentacontrols]

For aggregate mass flow rather than individual components, if the velocity is not too high you may be able to do this with a Coriolis mass flow meter or perhaps industrial mass meter depending on pressure, temperature etc

 

[IRstuff]

If nothing else, the standard nVidia GPU easily blows away a Cray XMP.

TTFN
faq731-376

 

[controlnovice]

Coriolis is a no go as we would need much, much higher pressures on our vapor stream...

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This is normally the space where people post something insightful.