MEASURING TWO PHASE FLOW
MEASURING TWO PHASE FLOW
(OP)
Wondered if there is a way to measure two phase flow (steam and water) in a 20" pipe? thanks to all.
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MEASURING TWO PHASE FLOW
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MEASURING TWO PHASE FLOWMEASURING TWO PHASE FLOW(OP)
Wondered if there is a way to measure two phase flow (steam and water) in a 20" pipe? thanks to all.
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RE: MEASURING TWO PHASE FLOW
No more things should be presumed to exist than are absolutely necessary - William of Occam
RE: MEASURING TWO PHASE FLOW
In the process of designing 80 km of steam pipeline, my solution has been to measure the vapor phase at the destination (in this case, 250 injection wells) and subtract it from the total mass into the system. This will only work if you have some point in the system that gives you a baseline of the total flow to the system.
Another method would be to measure the condensate extracted. This is somewhat tricky, in that you'll need to measure the condensate before it's depressurized, since much if it will flash to vapor once depressurized.
Otherwise, you'll need to separate the phases, measure, and recombine the flow.
RE: MEASURING TWO PHASE FLOW
RE: MEASURING TWO PHASE FLOW
We inject two chemicals at a known rate. One chemical dissolves in the water phase and the other becomes a vapor in the steam phase. We them take steam and water samples and the concentrations of the two chemicals with give the steam and water phase flow rates. We get very good results.
We manufacture and sell the equipment if you are interested.
Regards,
Kevin Koorey
Century Resources, Wairakei. PO Box 341 Taupo, New Zealand
Phone +64 7 376 0924, fax +64 7 374 8508
kkoorey@centurydrilling.co.nz
RE: MEASURING TWO PHASE FLOW
RE: MEASURING TWO PHASE FLOW
The problem is (and will remain) that there is no such thing as steady state multi-phase flow. Every correlation assumes a particular sort of flow (e.g., annuluar, mist, wavy, etc.) and develops empirical data to "measure" that. In the real world flow regime is very dependent on total energy available (at a given instant) and at each band of energy the phases interact differently. I've watched multi-phase flow in clear plastic piping and at the same volume flow rate, pressure, and temperature you'll see every sort of flow regime at a given point in the piping over time. I've despaired of ever getting a measurement methodology that can compensate for very non-steady conditions.
David
RE: MEASURING TWO PHASE FLOW
We have measured two phase flow indirectly for a steam cooling system where water is sprayed into the steam path to cool it (Turbine bypass).
Normally it is recommended that the mixed flow rate is above saturation. Flow and temperature are measured down stream. If the mixture is below saturation then temperature remains at boiling point no matter what the mixture and flow cannot be effectively measured.
In this case we hade to measure the temperature, pressure and flow for both the coolant and steam. We developed a feed forward algorithm which equates the heat balance using enthalpy. The feed forward control system was linked to the coolant valve position.
Im not sure if this helps your application.
RE: MEASURING TWO PHASE FLOW
I have to assume that it is steam line and not super heated.
Coriolis will not work no one makes a 20" meter. Plus if we are talking about high pressure steam we have high heat issues that may affect the ability of an ultrasonic meter to work correctly due to high heat.
An orifice meter in combination with dp, pressure, and temperature transmitters measures mass flow quite well in steam service in combination with good staturated steam tables from good source. Crane Technical Paper No. 14.
Rosemount makes a flow transmitter with the above three integrated into one device. Rosemount 3095 multivariable
flow meter does steam mass flow calculations from ASME steam tables.
On your orifice taps I would make the taps at 45° angle up from horizontal. If you suspect lots of liquid carry over
on your orifice plate I would put a 1/4" weep hole at bottom
of plate to let liquid through. Also I would double the required distance for required pipe run. On a 20" line we are talking long line 30 pipe diameters upstream and 20 pipe diameters down stream. Also put your Thermowell for
RTD beyond 20 diameters downstream. I would install the Flow Transmitter as close as possible to the orifice taps with seal pots to reduce temperature on transmitter.
Hope this helps and Rosemount can give you some guidance with the 3095 Mass flow measurement for steam.
Mark
RE: MEASURING TWO PHASE FLOW
RE: MEASURING TWO PHASE FLOW
As dbevil stated, you can measure the condensate after draining it.
Also, is there no place to measure steam flow at the source while it is still "dry"?
RE: MEASURING TWO PHASE FLOW
Good point you'r raising.
Simple answer: We have a Geothermal (Natural) field with 8 wells, each produce mix of steam and water. We would like to measure the flow of each well for predicting well maintenance and cleaning. Other point is when we have a desturbance at the main header to know which of the well is responsible and take care of this well only.
See, not everyone got dry and clean steam...
RE: MEASURING TWO PHASE FLOW
RE: MEASURING TWO PHASE FLOW
RE: MEASURING TWO PHASE FLOW
I got caught claiming there where no big coriolis meters. Rheonics make at least an 18" i've heard, so maybe bigger. Plus i know who has the technology to make mass meters any size you want and no bigger than an equivalent turbine meter... but try getting them to manufacture!
Solartron ISA make multiphase meters (as do many others) for hydrocarbons and the Dualstream II is a two phase meter for natural gas production. (www.solartron.com)
So if enough people need something, someone will sooner or later solve the problem. In this day and age it may mean that someone already has your solution and is just shy about letting the world know about it!
RE: MEASURING TWO PHASE FLOW
RE: MEASURING TWO PHASE FLOW
I concur with other observations, ultrasonics is perhaps the best bet.
Kenneth J Hueston, PEng
Principal
Sturni-Hueston Engineering Inc
Edmonton, Alberta Canada
RE: MEASURING TWO PHASE FLOW
For your question what we do with the liquid phase: We convert the heat into Electricity. Please stop at:
http://www.ormat.com/index_technology.htm
and see the Binary cycle Energy Converter.
RE: MEASURING TWO PHASE FLOW
Alternately an impact device could measure the momentum and etc. etc..
If one is measuring steam and condensate then there is going to be a lot of wear. A U tube device measuring flow will experience the same results.
If one takes a model such as Briggs....or another and uses different size lines with measurements in each line then perhaps an empirical relationship could be developed.
Sure that there is a way but don't know a device capable of doing it, only ideas.
RE: MEASURING TWO PHASE FLOW
http://www.gepower.com/panametrics/en_us/pdf/papers/ur234.pdf
RE: MEASURING TWO PHASE FLOW
If you are just trying to see which wells are running down you can monitor the wellhead pressure of each well and the manifold pressure. The differnace will be proportial to the flow from each well.
We use this method along with the tracer flow testing above.
Cheers
Kevin
RE: MEASURING TWO PHASE FLOW
RE: MEASURING TWO PHASE FLOW
Other thing is to try and measure the two phase flow with the Portable Ultrasonic Flow Meter.
Thanks to all - ilan
RE: MEASURING TWO PHASE FLOW
As a senior engineer, you just delegate the task of designing and implementing a two-phase flow meter to Reuven. I guarantee it will get done, and very interestingly.
I like Kevin's approach. If you can do careful flow tests on the wells, with James tubes and weir boxes, you can generate curves for steam and brine flow vs wellhead pressure. Then, when the wells are in service, the curves can be used to reasonably approximate the operational steam and brine flows.
There are orifice plate correlations for two-phase flow, but as was previously mentioned they are very dependent on flow regime. Also, to get reasonable results, the pressure drop across the orifice must be fairly high, more than 20 psi, which is not good for the well production. I don't like any orifice plate in a two-phase line for that reason alone. Millions are spent on the well and piping system in order to get the fluid to the plant and it doesn't make sense to me to put any intentional restriction in the pipeline.
I like Kevin's dual tracer concept also, but have never used it.
RE: MEASURING TWO PHASE FLOW
RE: MEASURING TWO PHASE FLOW
I will eliminate the Orifices as per your comments.
What Reuven has to do here?
RE: MEASURING TWO PHASE FLOW
Reuven has a world-wide reputation for resourcefulness and correcting engineer's mistakes in the field. I was joking about him devising a two-phase flow meter.
I know of two patents for geothermal two-phase flow, although I don't know the details of the devices. One patent is held by Paul Spielman, a reservoir engineer at Coso, and the other by Doug Jung at Two-phase Engineering and Research in Santa Rosa, CA.
Neither of the devices have reached the commercial stage as yet, but it might be worthwhile to contact the inventors. It seems that there should be a strong demand for commercial two-phase flow meters.
Bob
RE: MEASURING TWO PHASE FLOW
May be you all will find it interesting to know.
I contacted a small company with great idea.
They developed a small sensor, based on heating cooling and temp. measuring (all in one sensor) that can calculate in two phase flow (Steam and water or cooler gas - liquid systems like air conditioning system) the precentage of liquid in the gas flow. The instrument gives an on line measuring which is fed into the PLC / DCS for dataloging or control.
The instrument is already in use by aircrafts air conditioning system and the company is now checking the option to convert it to steam - water aplications. If any of you think it interesting please leave a note to Dr. Gadi Golan from ATCT (www.ATCT.co.il) at: Gady@atct.co.il
This instrument is not yet at the company site but I hope it get there soon.
RE: MEASURING TWO PHASE FLOW
Ken Shumway
Ford, Bacon and Davis, LLC
RE: MEASURING TWO PHASE FLOW