Can You Suggest Flowmeter for Corrosive Gas ?

Of what material is the line constructed, please?

Not my area of expertise but would an ultrasonic flowmeter work? No need for anything inside the pipeline.

An orifice plate meter (D/P) with temperature compensation should work well.

If a review of the meter performance information from a reputable manufacturer is too confusing, a call to the technical support department is free and will solve which meter will work best in your application.

Please suggest Orifice Material of construction ( Moc )

The same material as is the pipe in which it is to be installed?

@ PWSlack - line is of SS316

@ Nigh - yes ultrasonic is a good solution and we also thought of that. but this gas is coming from battery limit and we are not sure if gas contains some particulate matter or not. So transit time ultrasonic may give erroneous reading if it is not clean.

@Shockhiscan - Actually we are not able to use orifice as pressure drop required is too small. we did consider venturi though, but its a very expensive solution.

I thought that ultrasonic needed to have particulates or bubbles in order to have something to measure?

I think doppler type ultrasonic needs dirty liquid or gas bubbles to reflect from... but its for liquids only

The ultrasonic based on transit time needs fluid to be clean... but a colleague of mine recommended Emersons Multipath ultasonic flowmeter.

The operating pressure of Operating pressure 60kpag is a little less than 9 psig.

I am unaware of any transit time ultrasonic clamp-on flow meter than can measure gas at that line pressure in metal pipe. I'd want to see it before I'd buy it.

Siemens has a good chance of measuring flow at that pressure in plastic pipe, but then there's the question on the use of plastic pipe.

@Iris - Though this was not a clamp-on type ultrasonic which we were planning to use. but yes you are right... the operating pressures are too low and therefore this solution will not be appropriate.
According to this operating pressure is 345-27,579 kPa

http://www2.emersonprocess.com/siteadmincenter/PM%20Daniel%20Documents/T-20-Series-Gas-USM-Transducers-Flyer.pdf

It depends on the <...plastic...> and it depends upon the <...acid...> in the gas, neither of which have been disclosed so far. Is there a Process Engineer at the facility who can advise?

Pitot tube and an inclined manometer would fit the spec at the moment. Check out the Dwyer catalogue (usual disclaimer).

Material of pipe is SS316

And fluid is acid gas (very high H2S concentation with presence of water vapor).

Pitot tube or annubar we are not preferring as we are not sure if the gas is dirty or not.The acid gas is coming in from battery limit. Process engineer is not sure if gas may have some particulates.

yes, we are in talks with some vendors to provide an ultrasonic solution for such low operating pressures if possible.

Flexim G801 , noncontact type uitra sonic meter.should be a better solution

http://www.flexim.com/en/fluxus-g801