Sour gas flowmeters

[elektroeng]

Gents,

We are revamping a claus unit and have some problems with our exting orrifice flow meters. I was wondering if there are any smarter sollutions.

We've looked into :
- thermal flowmeters, not much references, need constant gas composition for correct measurement, the sensor can load up with impurity's.
- ultrasonic flowmeters, relatively expensive but can work when heated and traced properly.

Do you have any suggestions, experiences or tips ?

Thank you very much,
Regards

 

[Jason5000]

Acid gas, fuel, air, or are you trying to meter some process gas downstream of the reaction furnace?

 

[elektroeng]

Hi,

Its the sour gas feed into the claus unit that we want to measure.

We have two sour gas suppliers :
- one coming from a HDS unit that has been treated in an amine unit.
- one coming directly from our sour water stripper units.

=> both streams contain H2S gas going into the claus unit.

 

[dcasto]

You need a meter that does not require contact with the fluid or having the process opened up to maintain. Normally I would specify orifice meters.

Today, I'd go with external ultrasonic meters. lowest risk to humans.

 

[Jason5000]

As dcasto says you can always go with the old faithful orifice plate. I've also seen Venturi meters used in this application so you get lower DP, therefore lower backpressure on your amine units. You'll end up with lower regen bottoms temp, which is better for your amine, and less energy input required to the regenerator. I've heard of vortex meters being used on sour water stripper off gas too. I've never seen it in practice, but I have seen vortex meters in other fouling services like sulfur pit sweep meters. A little nitrogen purge on the impulse lines for your sour water stripper off gas might not hurt if you have any salt issues, but be careful as not adjusting any purge properly can throw off the meter reading.

 

[marianito]

Hi everybody:
We are starting to built a new Claus complex in a refinery in Argentina, and the sour gas flow meters are venturis made of stainless steel, I think they would be Daniel, because the available pressure is very very low.
For the clauss off gas, the basic engineer contractor put an annubar, but we don't see too much future..

best regards
mariano

mariano

 

[JLSeagull]

The technology selection depends upon the line size, operating conditions, fluid composition, etc. If you don't like the averaging pitot, consider a V-Cone, vortex shedder, etc. Few select venturi flow meters these days due to the many technology choices. Other technologies may be less costly and more accurate, have higher turndown or require a shorter meter run.