Brine flow measurement, non-contact

[NoHoCa]

Our client wants to measure the flow rate of a brine stream (reject from RO/NF). It's closed pipe on the discharge of a centrif pump. They say they don't like mag meters but would consider ultrasonic if it's not "too expensive". I'm thinking coriolis is elegant but perhaps costs more.

Probably a 4" line, 900 gpm (up to 10,000 lb/min). TDS ~5000 ppm with occasional slugs. TSS 5ppm plus slugs of filter backwash. Chlorine (gas) residual 2000 ug/L.

I'm unsure of transit time measurement because maybe there's too much junk in the water? Doppler? Thanks for any thoughts.

 

[sparky970]

Does you client have a reason for not wanting to use a mag flow tube?

 

[NoHoCa]

I suspect they've experienced electrode fouling on similar applications. Usually they're this adamant when they've been bitten.

 

[khan101]

Try CiDra flowmeters. They are non-intrusive and do not require a shutdown for maintenance or installation. Slightly higher side on cost but maintenance free and reliability is excellent. You can look for cidra sonartrac flowmeters on internet.

 

[roydm]

You Say "Non Contact"
Personnaly I wouldn't touch a Doppler with a barge pole.
I have had some success with Transit time where there are no bubbles of gas. Try a portable before you commit to one.
A coreolis should work but your line velocity is high for a 4", it would also be very expensive, good choice where you dont have much straight pipe
The range looks about right for a 4" Vortex meter (a typical has range 30 - 992 gpm) they work well for most liquids but need considerable straight pipe e.g. 20/10 Diameters for good accuracy.
Let us know how you get on.
Regards
Roy

 

[sparky970]

A magmeter with Ti electrodes and grounding rings would work good for this application. We use this on our brine feed to our electrolyzers. Don't forget material selection and grounding is very important for the magmeter to work properly and resist corrosion.

 

[NoHoCa]

I'm doing all I can to dissuade them from transit time.

Turns out a budgetary quote on a 4" coriolis meter is about $50k, which is impossible for a non-revenue generating measurement.

Mag with upgraded electrodes will be our hard sell, although I did find some merit in considering vortex (which I hadn't used before). According to the Rosemount material selection guide for their mag flow tubes, Hastelloy electrodes should be fine with 'brackish' water. Thanks very much for all the input. Flow meters are so particular and it's nice to have input from a variety of users and industries.

NoHoCA
(ME not CE, perhaps I'll redo my membership here to clarify)

 

[roydm]

NoHoCa,
A 4" vortex should be less than $3,000. They are very reliable and simple to wire.
The engineering company I work for buy about 100 per year for liquid and steam service.
Good Luck
Roy

 

[ilan7]

NoHoCa
If not ultrasonic I'll recommad using V-con flow meter. Much better then Orifice and Annubar. See

http://www.mccrometer.com/

 

[Standingback]

I apreciate that experience often leads us to make rational decisions, but my experience of current time of flight and even dopplar devices is that modern devices are head and shoulders above similar technology of 5 yrs ago. so my opinion has changed with time.

I would suggest hiring a trial unit of whatever technology you go for, and not get sucked by manufacture's claims.

A new non intrusive device which may overcome the issue of bubbles and solids is a time of flight/doppler hybrid.

http://sciencelinks.jp/j-east/article/200703/000020070307A0005064.php

or

http://www.sciencedirect.com/scienc...serid=10&md5=094bbf25230ebddf220e18a51b42999e

I haven't seen it in Usa of europe yet, but I beleive it is available in Japan

http://www.fic-net.jp/eng/library/catalog/pdf/ECXNO632b.pdf

I trust this helps,
Mlv

http://www.coulton.com