Steam Flow Measurement
Steam Flow Measurement
(OP)
I want to measure steam flow and temperature without shutting down the system. System is 100 psig saturated steam nominal three boilers of 1000 bhp each.
What is the best type of measurement devices for this application?
What is the best type of measurement devices for this application?





RE: Steam Flow Measurement
http://www.invensys.com
RE: Steam Flow Measurement
There are other methods, with various accuracies and expense. There are also several vendors, including Foxboro (Invensys) already mentioned, Rosemount (Emerson), ABB, Honeywell, etc.
Is this just a temporary measurement? Since you don't want to shutdown, it may be. In that case, you might look into an Annubar that can be inserted through a valve. You could also insert a separate thermometer, I guess. I don't think a clamp-on ultrasonic flowmeter will work in steam, but you might check with Panametrics or Controlatron.
RE: Steam Flow Measurement
Temperature of saturated steam at 100 psig is approximately 327.99 deg F (164.44 deg C) from steam tables.
When running at full capacity, you should have approximately 103500 lbm/hr of steam flow. Size your flowmeter accordingly. (34.5 lbm/bhp-hr x 1000 x 3)
Good luck trying to measure your parameters without shutting down the system. We use vortex flowmeters from Foxboro, but they're installed in the piping downstream of the boilers. You'll have to check on the suitability of clamp-on ultrasonic meters for steam like ICman said. I think I remember seeing a presentation by a Panametrics rep that said steam could be measured with their ultrasonic, but I don't know if the transducers had to be wetted or could be clamp-on.
xnuke
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.
RE: Steam Flow Measurement
Other issue is the calibration of this meter. If we calibrate the meter to say 100psig operating pressure but the boiler can only do 80 psig because of the combustion settings are not working properly, we will have false readings. By density adjustment a differential or velocity type meter will have an error equal to:
For differential devices like orifice plates,
%=(SQRT(S.V.actual/S.V.specified)-1)x100
For velocity devices like vortex,
%=((S.V.actual/S.V.specified)-1)x100
% is percent over or under reading.
S.V. is specific volume of saturated steam at operating pressure.
(See Spirax Sarco Design of Fluid Systems Manual page 60)
This usually means an over reading of the real lbs/hr when really the boiler has not reached its rated capacity.
Is there someone with the same situation?
RE: Steam Flow Measurement
RE: Steam Flow Measurement
if the plant you dont want to shutdown you can put on
vortex flowmeter at bloiler feed water end and further can directly relate with the steam with its density correction at that pressure of 100psig also pressure increase in steam is proportional to temperature here we can say approx. 162oC. Forbes & marshall(India-mumbai)can very well guide on this matter.
adil
RE: Steam Flow Measurement
Mark
RE: Steam Flow Measurement
or if the pressure is high you can use ultrasonic flowmeters... Panametrics came up with those.