gas erosional velocity discussion
TRANSCRIPT
Gas Erosional Velocity Discussion
2012 Pipeline Knowledge Retention Conference Houston, Texas November 6-7, 2012
Panel Members
Chris Williams Cheniere
Eileen Steinbach DCP Midstream
Ron Matthews Emeritus
Anders Johnson Kinder Morgan
Ken Skweres Spectra
Thomas Rey Gregg Engineering
Erosion Velocity Discussion
� Definition
� Importance
� Factors
� Examples
� Measurement techniques
� Mitigating options
� Safety is No.1 prudent designs No. 2
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2012 Pipeline Knowledge Retention Conference Houston, Texas November 6-7, 2012
Note the points made in these presentations are for discussion purposes only. Engineered systems must be designed by qualified individuals that account for the site specific conditions.
3Erosion – Definition
�Erosion is the loss of material due to solid or liquid particle impact on the material’s surface
� “It is a battle of the steel’s yield stress and fracture
mechanics vs. the surface morphology” 1
� Important for piping systems since loss of material
leads to wall thinning and loss of pressure containing
capabilities
�For correctly designed transmission line systems,
problems due to erosion are rare
1 “Understanding equipment erosion”; Ray Cocco, PBE October 2012, www.powderbulk.com
4Factors Affecting Erosion
�Particle Speed & Mass
�Material MOE/Ductility
�Particle Angle of Attack
�Particle Concentration
�Material Surface Roughness
2012 Pipeline Knowledge Retention Conference Houston, Texas November 6-7, 2012
Note the points made in these presentations are for discussion purposes only. Engineered systems must be designed by qualified individuals that account for the site specific conditions.
5Where Erosion Shows Up
�Bends/Changes in Direction
2012 Pipeline Knowledge Retention Conference Houston, Texas November 6-7, 2012
Note the points made in these presentations are for discussion purposes only. Engineered systems must be designed by qualified individuals that account for the site specific conditions.
6Where Erosion Shows Up
�Blind Tee’s
�Headers
7Where Erosion Shows Up
�Reducers
�Re-enforced Welds
8Calculating Permissible Velocity
�API RP 14E
�Basic Equation� Vmax in f/s
�Terms
� Note – This is not a ‘one size fits all’ equation there are many factors which we will explore in a real world example
Equation9
Note the points made in these presentations are for discussion purposes only. Engineered systems must be designed by qualified individuals that account for the site specific conditions.
10Case Studies
� Meter Station example
�DCP Midstream
2012 Pipeline Knowledge Retention Conference Houston, Texas November 6-7, 2012
Note the points made in these presentations are for discussion purposes only. Engineered systems must be designed by qualified individuals that account for the site specific conditions.
Velocity concerns associated
with particle entrainment in a
meter tube
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2012 Pipeline Knowledge Retention Conference Houston, Texas November 6-7, 2012
Note the points made in these presentations are for discussion purposes only. Engineered systems must be designed by qualified individuals that account for the site specific conditions.
Particle build-up/dropout
observed in the meter tube12
Meter tube has been in service for several years – no indications of wall
loss within the tube. However observed particle dropout warrants further
investigation. Ascertain what is happening to the downstream piping
Note the points made in these presentations are for discussion purposes only. Engineered systems must be designed by qualified individuals that account for the site specific conditions.
Gas analysis
� Pipeline quality gas
� 1023 BTU
� Upstream filtration
� No indication of free liquids
� Solids observed in the meter tube
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2012 Pipeline Knowledge Retention Conference Houston, Texas November 6-7, 2012
Note the points made in these presentations are for discussion purposes only. Engineered systems must be designed by qualified individuals that account for the site specific conditions.
Pipe Velocities – Pipe, Fittings,
and Appurtenances
Flow Rate
(MCFD)
Pressure
(PSIG)
Pipe I.D.
(INCHES)
Temp
(Deg. F)
Velocity
(FPS)E
lbow
110,000 230 15 40 63
124,000 230 15 40 71
150,000 230 15 40 85
200,000 230 15 40 114
220,000 230 15 40 125
275,000 230 15 40 157
Valv
e
110,000 230 9 40 174
124,000 230 9 40 196
150,000 230 9 40 237
200,000 230 9 40 316
220,000 230 9 40 348
275,000 230 9 40 435
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Check velocities through the entire flow path – time of day, time of year
Observations
� Pipe O.D. 16”
� Pipe wall 0.500”
� Pipe Grade X-42
� Seamless pipe
� Velocity estimated to exceed 100 feet/second based on meter flow and delivery pressure hundred of hours per year
� No readily discernable excessive wear using ultrasonic thickness measurements
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2012 Pipeline Knowledge Retention Conference Houston, Texas November 6-7, 2012
Note the points made in these presentations are for discussion purposes only. Engineered systems must be designed by qualified individuals that account for the site specific conditions.
Measurement Techniques and
Analyses
� Ultrasonic thickness indicator
� Grid pattern established for measurements
� X-ray
� Magnetic Particle (SCC)
� Examine upstream piping
� Component(s) in question
� Downstream piping
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2012 Pipeline Knowledge Retention Conference Houston, Texas November 6-7, 2012
Note the points made in these presentations are for discussion purposes only. Engineered systems must be designed by qualified individuals that account for the site specific conditions.
Measurement Techniques and
Analyses
� Ultrasonic thickness indicator readings
� Downstream piping wall variations were observed but are not unlike any inspection of seamless pipe
� 93.5% of nominal 500 wt = .4675" minimum allowed wall thickness
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Note the points made in these presentations are for discussion purposes only. Engineered systems must be designed by qualified individuals that account for the site specific conditions.
Recommendations
� Annual check of high velocity piping where entrained particles may be present using ultrasonic measurements
� Complete flow path study
� Meter tube inspection
� Gas analysis
� Coupons – optional
� X-ray
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2012 Pipeline Knowledge Retention Conference Houston, Texas November 6-7, 2012
Note the points made in these presentations are for discussion purposes only. Engineered systems must be designed by qualified individuals that account for the site specific conditions.
Conclusion
� Pipeline gas velocity is not a sole determinant
� In this example there was no readily discernable excessive wear based on the ultrasonic thickness measurements in spite of possible particle entrainment and bends in the flow path
� Traditional “rules of thumb” may be overly conservative for pipeline quality natural gas systems
� Careful checks should be made but automatic pipe replacements avoided unless there is a reason to believe there is a safety issue
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2012 Pipeline Knowledge Retention Conference Houston, Texas November 6-7, 2012
Note the points made in these presentations are for discussion purposes only. Engineered systems must be designed by qualified individuals that account for the site specific conditions.
Thank You
Questions?
2012 Pipeline Knowledge Retention Conference Houston, Texas November 6-7, 2012
Note the points made in these presentations are for discussion purposes only. Engineered systems must be designed by qualified individuals that account for the site specific conditions.
Chris Williams Cheniere
Eileen Steinbach DCP Midstream
Ron Matthews Emeritus
Anders Johnson Kinder Morgan
Ken Skweres Spectra
Thomas Rey Gregg Engineering
References:
� DNV Recommended Practice RP O501, “Erosive Wear in Piping Systems; http://www.dnvusa.com/industry/maritime/rulesregulations/dnvrules/offshorecodes/recommendedpractises.asp
� “Understanding equipment erosion”; Ray Cocco, PBE October 2012; www.powderbulk.com
� Course No O-5001, “Gas Pipeline Hydraulics”; www.pdhengineer.com
� API RP 14E, “Recommended Practice for Design and Installation of Offshore Production Platform Piping Systems”; http://www.api.org/publications-standards-and-statistics.aspx
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2012 Pipeline Knowledge Retention Conference Houston, Texas November 6-7, 2012
Note the points made in these presentations are for discussion purposes only. Engineered systems must be designed by qualified individuals that account for the site specific conditions.