FLOWMETER TECHNOLOGY

[compo]

Appreciate any feedback on flow meter selection types and suppliers who have the capabilty to accurately measure hydrocarbon gas predomin. methane over a wide temperature range and specifically at the cold end- gas temperatures range from -80 to -100degC, upper end 100degC. The application is mandatory measurement of flared gases from our flare knock out drum.

 

[quark]

Density compensated averaging pitot tube type (Anubar) can be an option in your case. I saw them being used for methane, NG and other gases.

Try Fischer Rosemount and Endress+Hauser. I doubt whether Yokogawa has these models.

 

[JLSeagull]

-100degC to 100degC
Sounds like a stainless steel line, lots of straight run, correct?
What flow rate range or ranges? Flare applications often require extreme turndown to indicate the sweep and some normal venting - and to cover major blowdown releases. Turndown is a significant issue with selecting the type of flow meter or meters.
What pipe size?
How accurately?
What ambient?
I assume electronic.

I have seen multiple range thermal mass flow meters in flare applications except not that cold.
The head type flow meters have less turndown than some technologies. The annubar is an example of a head type flow element. We accept higher claims for turndown these days due to the high transmitter accuracy. In a warm climate the temperature is not a significant factor. Mount the transmitter two meters from the element and the transmitter is not exposed to the extreme cold. However, if this is Siberia then heat trace may be the solution.
There are many choices for other technologies. These include vortex shedders, ultrasonic transit time transmitters, etc.

Corriolis meters might be good for cold service but not big flow.

 

[Ashereng]

-100°C to 100°C. That is into cryogenic range. That is quite a range.

A 4" Micromotion coriolis can do 108,654 SCFM at 50 psi pressure drop on natural gas (MW 16.675) at 68°F and 500 psi. It has a process fluid temperature range of -50°C to 125°C, if you can get away with -50°C.

I have never gone down that cold. I really can't think of anything else aside from nuclear, and I don't have any experience with that.

"Do not worry about your problems with mathematics, I assure you mine are far greater."
Albert Einstein
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[Ashereng]

compo,

You may want to consider moving this post to

Measurement & control instrumentation engineering Forum
(5048 members)
forum698

You may have more luck.

"Do not worry about your problems with mathematics, I assure you mine are far greater."
Albert Einstein
Have you read FAQ731-376 to make the best use of Eng-Tips Forums?

 

[JLSeagull]

Installation methods to handle -100 deg C are common in ethylene and gas processing.

 

[Ashereng]

JL, Can you provide an example?

"Do not worry about your problems with mathematics, I assure you mine are far greater."
Albert Einstein
Have you read FAQ731-376 to make the best use of Eng-Tips Forums?

 

[JLSeagull]

I will post a new topic in Measurement & control instrumentation regarding cold service installation details.