April Proving Ultrasonic flowmeters with small volume provers

Transcription

1 April 2018 Proving Ultrasonic flowmeters with small volume provers

2 Proving concepts Overview Uni-directional ball provers Bi-directional ball provers Master meters Small volume provers 2

3 Perception today - It doesn t work in combination with ultrasonic flowmeters - Only in combination with master turbine meter - Only with significant number of multiple passes per run to comply to API uncertainty of 0.027% 3 main manufacturers of Small Volume Provers: Emerson Honeywell FMD (Flow Measurement Devices) - All with different displacer launching technology: Plenum Pressure Chain Belt drive 3

4 API requirements In the API Ch. 4.3, 3 methods are described to calibrate a flowmeter with a SVP: 1. Performing 5 proving runs (groups) of each 1 pass 2. Performing up to 20 proving runs (groups) of each 1 pass 3. Performing 5 to 20 proving runs (groups) with multiple passes per run (as an example 3, 5 or 10) Runs Repeatability Band % (R) Uncert. % 3 0,02 0, ,03 0, ,05 0, ,06 0, ,08 0, ,09 0, ,10 0, ,12 0, ,13 0, ,14 0, ,22 0,027

5 Small volume prover test Output 5

6 Start Flow Ultrasonic flowmeter with LOW sampling rate 12 st nd Pass Bad repeatability LAUNCH STOP Time Pre-run 6

7 What influences the results of calibrating ultrasonic flowmeters How to overcome these influences - When the displacer is launched a pressure disturbance will be generated, resulting in a flow rate spike, with the risc that it will NOT be damped out when the displacer reaches the measurement section i.e. first detector switch. - Meter Under Test volume pulses are not symmetrical distributed - Short measurement time of < 1 seconds - Low sampling rate of the ultrasonic flowmeter resulting in high repeatability without reaching API requirements (or only with a high number of passes per run) - For Small Volume Prover manufactures to reduce the effect of launching the displacer to avoid significant flow rate spikes - For Ultrasonic flow meter manufacturers to improve the sampling rate significantly to follow every minor flowrate deviation, to reach the API repeatability requirement of 0.05% for 5 runs with 5 (or less) passes per run.

8 Start Flow Ultrasonic flowmeter today much faster sampling time 1 st Pass 2 nd Pass Good repeatability LAUNCH STOP Time Pre-run 8

9 Why it is working today Enhanced software with advanced signal processing methods provides improved measurement accuracy. Maximum possible output frequency of 10 khz Using the floating average technology, 250 output frequency updates per second Based on field tests, a minimum pass duration time is recommended as 1 second for a 4 inch flowmeter up to 2 seconds for a 12 inch flowmeter. With 1 second pass duration time, a repeatability can be reached of 0.05 % for 5 runs with 5 (or less) passes each, reaching an uncertainty of %, to be in compliance with API. High speed sampling Enhanced filtering an algorithms Build in diagnostics and data logging One converter fits multiple sensors Integrated audit trail 9

10 Maximum flowrates confirmed by SVP manufacturers based on recent data sheets Manufacturer V b (litres) Q max (m 3 /hr) Duration for 1 pass (sec) A B C Based on 1 and 2 seconds, pass duration time Manufacturer Q Duration for 1 pass 1 sec 2 sec A B C

11 Process flowrates for an ultrasonic flowmeter based on 7m/s example for a 12 inch Size 10 m/s m 3 /hr 7 m/s m 3 /hr 12 inch Based on a pass duration time of 1 second and Process flowrate based on 7 m/s A 12 inch ultrasonic flowmeter can be calibrated with a Small Volume Prover A 16 inch ultrasonic flowmeter can be calibrated upto 5 m/s i.e m 3 /hr 11

12 Test at flow lab. Meter size : 8 inch meter Medium : Water Prover : FMD-060 (150 liters) Max. flowrate : m 3 /h 12

13 SVP proving of an 8 inch ultrasonic meter 13

14 Test set up for the calibration of a 8 inch ALTOSONIC 5 with a Small Volume Prover Base volume SVP: 284 litres Max flowrate : 800 m 3 /hr Velocity A-5 : 7 m/s Number of runs : 5 Passes per run : 3 Criterion : API Medium : water 14

15 Calibration results of a 8 inch ALTOSONIC 5 R=0.05 % R=0.05 % R=0.04 % R=0.04 % 15

16 8 inch ALTOSONIC 5 calibrated with a Small Volume Prover Time Flowrate (m 3 /hr) A-5 velocity (m/s) Pass time (sec) Avg pulses for 3 passes K-factor (p/m 3 ) summary 11: , ,470 avg pulses 8, , ,458 max puls 8, , ,458 min puls 8, , ,469 R (%) , ,474 STDEV (%) : , ,463 avg pulses 8, , ,471 max puls 8, , ,471 min puls 8, , ,468 R (%) , ,478 STDEV (%)

17 8 inch ALTOSONIC 5 calibrated with a Small Volume Prover Time Flowrate (m 3 /hr) A-5 velocity (m/s) Pass time (sec) Avg pulses for 3 passes K-factor (p/m 3 ) summary 11: , ,406 avg pulses 8, , ,411 max puls 8, , ,409 min puls 8, , ,419 R (%) , ,409 STDEV (%) : , ,399 avg pulses 8, , ,400 max puls 8, , ,400 min puls 8, , ,407 R (%) , ,412 STDEV (%)

18 Summary of calibrations Flowmeter size (inch) SVP Base Volume (litres) Flowrate (m 3 /hr) Pass duration (sec) Number of passes/run Number of runs Avg Pulses per run R (%) Uncertainty (%)

19 Field application Meter size Medium Prover : 12 inch meter : Crude : FMD-200 ( 500 liters) Customer is satisfied 19

20 Conclusions Ultrasonic flowmeters can be calibrated with Small Volume Provers The number of multiple passes/run depends on the single pass duration Minimum pass duration depends on flowmeter size, 4 inch flowmeter require 1 sec/pass large flowmeters (12 inch) require 1.8 sec/pass Calibration procedure and criteria are based on API recommendations High symetrical frequency/pulse output is mandatory for acceptable API results Buffering will result in a-symetric pulses and consequently bad repeatability The basis for SVP calibration, is 5 runs with 3..5 passes per run 20

21 Thank you for your attention!