1. PIPELINE DESIGN ‘ THE ENGINEERING APPROACH’ SESSION OBJECTIVES THE ENGINEERING EQUATIONS TRANSMISSION LINE GAS FLOW LIQUID SYSTEM

2. SESSION OBJECTIVES At the end of the session students should be able to: 1.Describe the elements of the engineering equations 2.Perform pressure drop calculation using empirical formulae

3. THE ENGINEERING EQUATIONS Few flow problems can be solved with an acceptable degree of accuracy when using equations designed to fit idealized application. Flow regimes and associated pressure drop discontinuities are complex phenomena and require complex equations to predict their relationships. For engineering design purposes, several empirical formulae have been developed to fit particular circumstances in predicting flow capacity and pressure drop

4. Bernoulli’s Theorem Assumption: steady, frictionless, constant density flow along a streamline

5. Flow in Pipes and Reynolds Number Dimensionless number that may be considered as the ratio of the dynamic forces of mass flow to shear stress due to viscosity

6. Pressure Loss Due to Friction Flow is always accompanied by friction. A general equation for pressure drop due to friction is the Darcy-Weisbach equation

7. Pressure Loss Due to Friction Moody Diagram

8. Friction Factor and Effect of Pipe Roughness Laminar Flow (Re<2000) –Friction factor, f has a direct relationship to the Reynolds number –Pipe roughness has no effect on the friction factor –f=16/Re Turbulent Flow (Re>4000) –Friction factor, f depends on Reynolds number and the relative roughness of the pipe,  /D –f=0.042/Re 0.194 (large pipe >8”) –f=0.042/Re 0.172 (small pipe ≤8”)

10. Equivalent Length of Valves and Fittings The pressure drop effects of valve and fittings can be accounted for by addition of the equivalent lengths of the fittings to the actual piping length

11. EXERCISE A 10 in crude line handles 40260 bbl/day of oil of API gravity 39 o. The oil viscosity is 9.5 cp. The flow line is 6.15 miles long and discharges to a tank at atmospheric pressure (14.5 psi). The tank installation is 328 feet higher than the pump discharge. The pipe wall roughness is assumed to be 1500 in. Determine the necessary pump discharge pressure.