×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Mass Flow Measurement of mixed vapor

Mass Flow Measurement of mixed vapor

Mass Flow Measurement of mixed vapor

(OP)
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?

______________________________________________________________________________
This is normally the space where people post something insightful.

RE: Mass Flow Measurement of mixed vapor

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.

RE: Mass Flow Measurement of mixed vapor

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

RE: Mass Flow Measurement of mixed vapor

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?

RE: Mass Flow Measurement of mixed vapor

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.

RE: Mass Flow Measurement of mixed vapor

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

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

______________________________________________________________________________
This is normally the space where people post something insightful.

RE: Mass Flow Measurement of mixed vapor

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...

RE: Mass Flow Measurement of mixed vapor

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.

RE: Mass Flow Measurement of mixed vapor

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

RE: Mass Flow Measurement of mixed vapor

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

______________________________________________________________________________
This is normally the space where people post something insightful.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources