Erosional velocity

Erosional velocity

Erosional velocity is a velocity of the multiphase flow at which pipe erosion occurs.

Erosional velocity equation

Pipe erosion begins when velocity exceeds the value of

$v=\frac{C}{\sqrt{\rho}}$

C/SQRT(ρ) in ft/s, where ρ = gas density (in lb/ft3) and C = empirical constant (in lb/s/ft2) (starting erosional velocity). We used C=100 as API RP 14E (1984) suggested C=100 for continuous and 125 for non continuous service.

This is the empirical relationships for estimating whether erosion will occur in a system at a certain velocity used at PQplot.

Erosion

Erosion is normally expressed as a rate of metal loss, usually mm/year. It usually occurs in turns or protrusions; or with solids content.

One can relate Erosional velocity to a metal loss rate (see RP O501).

References

• Mokhatab S, Poe WA, Speight JG (2006) "Handbook of Natural Gas Transmission and Processing", Section 11.6 - Design Considerations on sales gas pipelines, subsection 11.6.1 - Line Sizing Criteria, Elsevier, 2006.

• RECOMMENDED PRACTICE RP O501 EROSIVE WEAR IN PIPING SYSTEMS. REVISION 4.2 - 2007. DET NORSKE VERITAS (pdf)