TransCanada / Daniel Using Advances Diagnostics to Identify Measurement Uncertainties Thomas Hart, TransCanada Martin Schlebach, Emerson/Daniel April 2018
Introduction Columbia Gulf is a subsidiary of TransCanada, one of the largest underground natural gas pipeline systems in North America Columbia Gulf delivers natural gas at a pipeline interconnect in Louisiana Single run ultrasonic meter with flow conditioner plate Installed in 2008 flow calibrated prior to installation Customer observed instability in USM diagnostics CEESI was consulted by Customer Audit noted a Profile Factor shift from initial flow calibration 2
Agenda Site overview, metering assembly configuration Initial Diagnostic indicators Analysis of data with potential causes and solutions Computational Fluid Dynamics used to help determine potential causes Review of initial 2008 calibration Field installation and testing Results of 2016 recalibration 3
Site Layout
Meter Configuration DIRECTION CHANGE 16 Daniel Senior Sonic ELEVATION CHANGE INLET TEE ELEVATION VIEW METER RUN OUTLET TEE FILTER SEPARATOR PLAN VIEW CONTROL VALVE NOISE REFLECTIVE TEES 5
Upstream 6
Downstream 7
Downstream 8
Original Field Diagnostics
Daniel USM Diagnostics Flow Velocities no flowrate changes to explain velocity shift Swirl Angle Profile Factor no flowrate changes to explain velocity shift actual flowrate changes Velocity Diagnostics Frequency Turbulence 10
10:10:08 10:10:20 10:10:32 10:10:45 10:10:57 10:11:09 10:11:20 10:11:32 10:11:45 10:11:57 10:12:09 10:12:20 10:12:32 10:12:45 10:12:56 10:13:08 10:13:20 10:13:33 10:13:44 10:13:57 10:14:08 10:14:21 10:14:33 10:14:44 10:14:56 10:15:08 10:15:21 10:15:32 10:15:44 10:15:56 10:16:08 10:16:20 10:16:32 10:16:44 10:16:56 10:17:09 10:17:20 10:17:33 10:17:44 10:17:56 10:18:09 10:18:20 10:18:32 10:18:44 10:18:56 10:19:09 10:19:21 10:19:32 10:19:44 10:19:57 Velocity (ft/s) Flow Velocities Maintenance Log 1 16 14 12 Flow Velocities FlowVelA (ft/s) FlowVelB (ft/s) FlowVelC (ft/s) FlowVelD (ft/s) AvgFlow (ft/s) 10 8 6 4 2 State 1 State 2 State 3 Three Flow Velocity regimes were identified 0 Time 11
10:10:08 10:10:20 10:10:32 10:10:45 10:10:57 10:11:09 10:11:20 10:11:32 10:11:45 10:11:57 10:12:09 10:12:20 10:12:32 10:12:45 10:12:56 10:13:08 10:13:20 10:13:33 10:13:44 10:13:57 10:14:08 10:14:21 10:14:33 10:14:44 10:14:56 10:15:08 10:15:21 10:15:32 10:15:44 10:15:56 10:16:08 10:16:20 10:16:32 10:16:44 10:16:56 10:17:09 10:17:20 10:17:33 10:17:44 10:17:56 10:18:09 10:18:20 10:18:32 10:18:44 10:18:56 10:19:09 10:19:21 10:19:32 10:19:44 10:19:57 Turbulence (%) Turbulence Maintenance Log 1 Turbulence 16 14 TurbulenceA (%) TurbulenceB (%) TurbulenceC (%) TurbulenceD (%) 12 10 8 6 4 2 0 Time 12
9:46:27 AM 9:46:40 AM 9:46:52 AM 9:47:04 AM 9:47:15 AM 9:47:27 AM 9:47:40 AM 9:47:52 AM 9:48:04 AM 9:48:15 AM 9:48:27 AM 9:48:40 AM 9:48:52 AM 9:49:04 AM 9:49:15 AM 9:49:27 AM 9:49:40 AM 9:49:52 AM 9:50:03 AM 9:50:16 AM 9:50:28 AM 9:50:40 AM 9:50:52 AM 9:51:04 AM 9:51:15 AM 9:51:28 AM 9:51:40 AM 9:51:52 AM 9:52:03 AM 9:52:15 AM 9:52:28 AM 9:52:40 AM 9:52:52 AM 9:53:03 AM 9:53:16 AM 9:53:27 AM 9:53:40 AM 9:53:51 AM 9:54:04 AM 9:54:16 AM 9:54:28 AM 9:54:39 AM 9:54:51 AM 9:55:04 AM 9:55:15 AM 9:55:28 AM 9:55:39 AM 9:55:52 AM 9:56:04 AM 9:56:15 AM Velocity (ft/s) Flow Velocities Maintenance Log 2 35 Flow Velocities FlowVelA (ft/s) FlowVelB (ft/s) FlowVelC (ft/s) 30 FlowVelD (ft/s) AvgFlow (ft/s) 25 20 15 10 State 1 State 2 State 3 5 Random and frequent shifts between Flow Velocity regimes were observed 0 Time 10 Minutes 13
MS4118 Ultrasonic Meter Issue The 16 Daniel Senior Sonic was showing the following symptoms: High Turbulence on all paths Profile Factor and Symmetry not consistent with Wet Calibration results Intermittent Turbulence pattern shift between high and low Turbulence Intermittent convergence and divergence of Path Velocities Intermittent Profile Factor and Symmetry shift from normal patterns Intermittent reversal of Swirl Angle polarity Daniel guidance prompted the following troubleshooting efforts: Investigate potential cathodic protection interference with meter electronics Investigate potential pulsation from upstream / downstream compression Investigate potential turbulence due to inlet / outlet piping configuration Install elliptical deflectors in upstream and downstream inspection tees 14
Initial 2008 CEESI Calibration 15
CFD Assumptions CFD was performed by Emerson to assist in proving the turbulence resulted from upstream tee geometry. Upstream flow entering the metering skid is uniform and is free from any fluctuations or periodic harmonics from a compressor further upstream. Control valve located downstream is steady and fixed at one position does not cause dynamic fine tuning operation due to its PID controller. Downstream pressure is stable and constant and is fixed at one value. Temperature is steady and constant. 16
Chordal Velocity Profile Development No Deflector Installed 17
Chordal Velocity Profile Development No Deflector No Deflector Installed 18
Flow Velocity Profile State 3 Separated flow 19
Elliptical Deflectors Both upstream and downstream inspection tees have flat end closures. The deflectors were installed so that the leading edge of the curved surface is even with the branch connection pipe i.d. On-Site Tests were performed for: d/s deflector only both u/s and d/s deflectors u/s deflector only Tests were performed at 100, 150, 200, and 250 MMscfd flowrates. 20
Modified Skid - Deflectors Elliptical deflector makes inlet tee resemble a 90 degree ell. 07/17/12 07/18/12 Cloudy and light rain 07/19/12 07/20/12 Sunny 21
Elliptical Deflectors 22
With Deflectors 07/17/12 07/18/12 Cloudy and light rain 07/19/12 07/20/12 Sunny 23
With and without Deflectors Deflector Installed No Deflector Installed 24
Diagnostics Pre/Post Deflector Installation Profile Factor With Deflectors 25
Turbulence Pre/Post Deflector Installation Turbulence With Deflectors 26
2016 Deflector Test & Recalibration
2016 CEESI tests with and without Deflectors 28
Long Term Diagnostic Data Installed condition data with Elliptical Deflector in upstream tee of meter run Improved Profile Factor, Turbulence, and Swirl Angle stability 29
Observations With Upstream T Joints Upstream T causes large scale swirl motions. Not all these swirling motions get attenuated at the CPA plate. Direction of swirl can be unstable. Flow instability indicates the formation of a standing wave and harmonic distortion due to the combination of upstream and downstream tee configuration. These instabilities cause large scale free stream disturbances in the middle of the pipe causing large scale fluctuations in the flow profile. 30
Observations With Deflectors Replacing upstream T with deflectors reduces swirl significantly. Most of the swirling motions get attenuated on or before CPA plate. There are only a few small scale instabilities upstream of Daniel ultrasonic gas flowmeter. Moderate swirl is seen at Daniel ultrasonic gas flowmeter. 31
Conclusions Installing deflectors in inspection hatches will improve flow downstream of CPA plate to the meter making flow suitable for flow measurement. Altering the piping configuration with deflectors will change the acoustic tuning and should eliminate the formation of longitudinal standing waves. It is important to try and send as much of the piping components as practical to the calibration facility to try and mimic the proposed field installation. This would include the meter assembly, and any end treatments. 32
Thank You Questions? 33