The American Petroleum Institute have guidelines (see API RP14E) for the flow velocity below which erosion damage is minimized. This maximum flow velocity is a function of velocity and density, and given by this equation.

where ρ is the gas/liquid density at the flow temperature and pressure, C is an empirical constant, and V is the maximum recommended velocity. This equation is only valid for horizontal flow with shear stress as the limiting factor

If ρ is in lb ft

^{−3}and V is in ft s

^{−1}, then C has units of lb

^{0.5}ft

^{−0.5}s

^{−1}. API RP14E recommends that C=100 lb

^{0.5}ft

^{−0.5}s

^{−1}for continuous service of liquid with solids, or C=125 lb

^{0.5}ft

^{−0.5}s

^{−1}for intermittent service (or values of up to 200 lb

^{0.5}ft

^{−0.5}s

^{−1}if the pipelines are corrosion resistant).

However, recent studies have recommended that higher C values are used, with values of 887 for 13Cr piping for "clean gas service" (see the paper "Improved Procedures for Estimating the Erosional Rates in High Offtake Gas Wells: Applications of University of Tulsa Flow Loop Derived Correlation" for more detail).

## 2 comments:

Dear Shamir before anything I want to thank you and to congratulate you for your site which is helping a lot in my job.

I used the ErosionalVelocity.xlsx spreadsheet and I think that the "fluid density" calculation formula must be "=(0,1204594*sl*P*(1-gor)+0,003484922*gor*sg*P)/(1,204151*0,0001*P*(1-gor)+gor*T*Z) " instead "=(0,1204594*sl*P+0,003484922*gor*sg*P)/(1,204151*0,0001*P+gor*T*Z)"

Hi Jorge. I believe you are wrong. If I use your formula and increase the gas to liquid volume ratio to a large number (lets say 1E10, meaning there's only gas inside the pipeline), I get negative densities.

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