What methods are used for dirty natural gas flow rate measurements (ex. on the gas-well's)?
The differential pressure-based meters are bad for it, because of high pressure loss, low rangeability and flow conditioning. Also, the impurities accumulate near the orifice plate. Moreover, the pressure drop may cause hydrates drop.
What do you think about using ultrasonic meters on the gas-well's?

 

Ultrasonics, work but are expensive. They will give you some accurate measurement. Turbines may be an option.

 

For biogases and so forth Schlumberger make the MTS mechanical turbine with high resolution pulse output option but if you are talking gas wells perhaps you could try Smith meters. I think they have a hoop mode straight flow path coriolis gas mass meter. If it isn't Smith it might be FMC. I'll try to find out for sure.

 

Turbines have moving parts. Also, dirt or impurities in the gas can damage the meter. Does anybody use this meter for dirty gas?

 

I have used EMCO insertion turbines with good success on blast furnace gas and other dirty gases. However, in order to work a certain application criteria must be followed. ASME Flow nozzles, or wedge meters are other options depending on line size. Contact me if you would like more information, we specialize in tough applications.

John Catch
[email protected]
http://inflowinc.com