liquid pipeline.ppt
- 2. PIPING SCHEDULE • NOMINAL PIPE SIZE IS EQUAL TO O.D. ( FOR PIPE SIZE 14 INCH AND LARGER PIPE SIZES ). ID 2 # PIPE SCH. 80 ( X STRONG ) ID 1 # PIPE SCH. 40 ( STD PIPE ) OD ID 3 # PIPE SCH. 160 ( XX STRONG ) • PIPES WITH THE SAME NOMINAL PIPE SIZE HAVE THE SAME O.D BUT DIFFERENT I.D. • NOMINAL PIPE SIZE IS NOT EQUAL TO THE OD. OR ID. OF THE PIPE
- 7. PUMPING STATION TERMINAL STATION BOOSTER STATION STORAGE TANK
- 8. PIPE LINE HYDRAULIC CACULATIONS B H total = h + Pipeline head losses + Terminal Head C PUMPING STATION TERMINAL A h
- 9. PRESSURE DROPAFFINITY LAWS IF THE FLOW RATE CHANGES FOR SAME PIPE SIZE P1 Q1 2 P2 Q 2 IF THE PIPE SIZE CHANGES FOR SAME FLOW RATE P1 P2 D2 5 D 1 IF THE PIPE SIZE AND FLOW RATE CHANGE P1 Q1 2 P2 Q 2 D2 5 D 1
- 10. R N It is the ratio between fluid inertia force and shear force R N It is a number expressing the degree of turbidity of fluids fluid inertia force R N fluid shear force Fluids flow Laminar Critical Turbulent R N < 2000 R N = 2000 - 4000 RN > 4000 fluid shear force A d RN (Dimensionless form ) R N 2 2 = = = = = L L L L fluid inertia force = mass acceleration = L 3 2 2 2 = L L
- 11. 1- LIQUIDS a- RN < 2000 ƒ = 64 / R N b- RN > 4000 ƒ depends upon (surface roughness ) Friction factor ƒ c- Max . Gas Velocity = Sonic Velocity V S = ( k.g.R.T ) 1 2 2- GASES FOR COMPRESSORS a- Adiabatic process P1 V1 P 2 V 2 T 1 T 2 b- Isothermal process (t = constant ) FOR PIPE LINES ƒ Lv2 ƒ L v 2 2 g D D 2 g = = K P = P P v 2 2 g
- 12. El = 100 ft 10 mi of 48 pipe, e =0.0003 ft El = 230 ft 2 1 6 Re 1.01x10 4 7.5x10 D e 0.0185 f
- 13. 13 Introduction • Head • Resistance of the system • Two types: static and friction • Static head • Difference in height between source and destination • Independent of flow Pumping System Characteristics destination source Static head Static head Flow
- 14. 14 Introduction • Static head consists of • Static suction head (hS): lifting liquid relative to pump center line • Static discharge head (hD) vertical distance between centerline and liquid surface in destination tank • Static head at certain pressure Pumping System Characteristics Head (in feet) = Pressure (psi) X 2.31 Specific gravity
- 15. 15 Introduction • Friction head • Resistance to flow in pipe and fittings • Depends on size, pipes, pipe fittings, flow rate, nature of liquid • Proportional to square of flow rate • Closed loop system only has friction head (no static head) Pumping System Characteristics Friction head Flow
- 16. 16 Introduction Pump performance curve • Relationship between head and flow • Flow increase • System resistance increases • Head increases • Flow decreases to zero • Zero flow rate: risk of pump burnout Pumping System Characteristics Head Flow Performance curve for centrifugal pump
- 17. 17 Introduction Pump operating point Pumping System Characteristics • Duty point: rate of flow at certain head • Pump operating point: intersection of pump curve and system curve Flow Head Static head Pump performance curve System curve Pump operating point
- 18. Assessment of pumps • Pump shaft power (Ps) is actual horsepower delivered to the pump shaft • Pump output/Hydraulic/Water horsepower (Hp) is the liquid horsepower delivered by the pump How to Calculate Pump Performance Hydraulic power (Hp): Hp = Q (m3/s) x Total head, hd - hs (m) x ρ (kg/m3) x g (m/s2) / 1000 Pump shaft power (Ps): Ps = Hydraulic power Hp / pump efficiency ηPump Pump Efficiency (ηPump): ηPump = Hydraulic Power / Pump Shaft Power hd - discharge head hs – suction head, ρ - density of the fluid g – acceleration due to gravity
- 19. Assessment of pumps • Sizing a Pump • a. Head and Pressure • Head in feet = Head in Psi X 2.31 • Sp.Gr • Head in Psi = Head in feet X Sp. Gr. • 2.31 • b. Brake Horse Power • i Centrifugal Terminology • BHP = Gpm X H (in feet) X Sp. Gr. • 3960 X Efficiency • BHP = Bbl/hr X H (in feet) X Sp.Gr • 5657 X Efficiency • ii Reciprocating Terminology • BHP = Gpm X psi • 1714 X Efficiency • BHP = Bbl/hr X psi • 2449 X Efficiency Sizing a Pump In the above expressions, gpm = US gallons per minute bph = Barrels per hour H = Total head in feet of liquid (Differential) psi = lb per square inch (Differential) Sp.gr = specific gravity of liquid to be pumped Motor Wattage Electrical HP input to Motor = Pump BHP Efficiency KW input to Motor = Pump BHP X 0.7457 Motor Efficiency
- 20. Pumps and Pumping Stations • Pumps add energy to fluids and therefore are accounted for in the energy equation • Energy required by the pump depends on: – Discharge rate – Resistance to flow (head that the pump must overcome) – Pump efficiency (ratio of power entering fluid to power supplied to the pump) – Efficiency of the drive (usually an electric motor) 2 2 1 1 2 2 1 2 2 2 pump L v p v p z H z H g g 2 2 L f minor f i v H h h h K g
- 21. Pump • (Total) Static head – difference in head between suction and discharge sides of pump in the absence of flow; equals difference in elevation of free surfaces of the fluid source and destination • Static suction head – head on suction side of pump in absence of flow, if pressure at that point is >0 • Static discharge head – head on discharge side of pump in absence of flow Total static head Static suction head Static discharge head
- 22. Pump • (Total) Static head – difference in head between suction and discharge sides of pump in the absence of flow; equals difference in elevation of free surfaces of the fluid source and destination • Static suction lift – negative head on suction side of pump in absence of flow, if pressure at that point is <0 • Static discharge head – head on discharge side of pump in absence of flow Total static head Static suction lift Static discharge head
- 23. Pump Total static head (both) Static suction lift Static discharge head Static suction head Static discharge head Static suction head Static suction lif Static discharge head Static d t Total static h ischarge he d ead a Note: Suction and discharge head/lift measured from pump centerline
- 24. Pump • (Total) Dynamic head, dynamic suction head or lift, and dynamic discharge head – same as corresponding static heads, but for a given pumping scenario; includes frictional and minor headlosses Total dynamic head Dynamic suction lift Dynamic discharge head Energy Line
- 25. Example. Determine the static head, total dynamic head (TDH), and total headloss in the system shown below. Total static head 730 ft 630 ft 100 ft pd =48 psig ps =6 psig El = 630 ft El = 640 ft El = 730 ft 2.31 ft TDH 48 6 psi 124.7 ft psi TDH Static head 124.7 100 ft 24.7 ft L H
- 26. Pump Power • P = Power supplied to the pump from the shaft; also called ‘brake power’ (kW or hp) • Q = Flow (m3/s or ft3/s) • TDH = Total dynamic head • = Specific wt. of fluid (9800 N/m3 or 62.4 lb/ft3 at 20oC) • CF = conversion factor: 1000 W/kW for SI, 550 (ft-lb/s)/hp for US • Ep = pump efficiency, dimensionless; accounts only for pump, not the drive unit (electric motor) TDH CF p Q P E Useful conversion: 0.746 kW/hp