Pump Station Design YP Seminar FINAL-PRINT Station Design.pdfPump Station Design & Layout ... Pumping Station Design,3rd Edition by SkSanks, Th b lTchobanoglous, Bosserman Pump Handbook,

David Bennett, P.E. Freese and Nichols  IncFreese and Nichols, Inc.November 16, 2010

Hydraulic Theory / Terminology System and Pump Curves System and Pump Curves Pump Performance

d l Pump Types (Water) and Selection Pump Station Design & Layoutp g y

What is a pump?A  hi  th t i t  ki ti   d  t ti l    A machine that imparts kinetic and potential energy to a liquid to force a discharge from the machine. A machine that moves a volume of liquid from a lower to higher elevation or energy level. A machine that moves liquid along a pipeline.

General form:E  E  E  E ET = Ep + Ev + Ez

Conservation of energy E1 = E2

Including losses & pumps:g p p Ep1 + Ev1 + Ez1 + EA = Ep2 + Ev2 + Ez2 + Ef

In terms of pressure head: In terms of pressure head: Hp1 + Hv1 + Hz1 + HA = Hp2 + Hv2 + Hz2 + Hf

Open to AtmosphereH  H  0 Hp1 = Hp2 = 0

For Large Reservoir Hv1 = Hv2 = 0

Simplified equationp q Hz1 – Hf1 + HA – Hf2 = Hz2

Hazen Williams:87.4

85.185.1)/100(002083.0(D

QCLH f

b h

D

Lv2

Darcy‐Weisbach:Dg

LvfH f 2

Minor Losses  Flow through valves  fittings  bends vKH

2 Flow through valves, fittings, bends Changes in flow path, direction, size

l l bl l l

gKHm 2

Minor losses are negligible in long pipelines

Static suction head / lift Static suction head / lift Head Terms Discharge Head (H ) Discharge Head (HA) Static Head (Hz) Pressure Head (HP)Pressure Head (HP) Velocity Head (Hv) Friction Head (Hf)( f)

Energy Grade Line (EGL) EGL = Hp + Hv + Hz + Hfp

Hydraulic Grade Line (HGL) HGL = Hp + Hz + Hf = EGL – Hv

Total Dynamic Head (TDH) TDH = Static (Hz) + Friction (Hf )

Determine static head Determine pipe size and length Determine pipe size and length Quantify friction and minor losses

l f Plot sum of: Static head Friction head from piping and minor losses

600

500

550

600

Plot: Hz + Hf vs. Q

400

450

300

350

feet)

200

250

Head (f

Hf = Friction Head

50

100

150

Friction Head

TDH = Hz + HfHz = Static Head

0

50

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22Flow (mgd)

Friction Head

Static Head

600

450

500

550

Plot System Curves for each Static Head 

250

300

350

400

d (feet)

condition

100

150

200

250

Hea

Maximum Static Head

0

50

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22Flow (mgd)

Average Static Head

Minimum Static Head

500

550

600

System ALWAYS runs at the intersection of the Pump and 

400

450

500

System Curves

300

350

feet)

200

250

Head (f

50

100

150

Maximum Static Head

Average Static Head

Mi i St ti H d

PUMP OPERATION

0

50

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22Flow (mgd)

Minimum Static Head

1 Pump

500

550

600

2 ‐ PUMPS

Parallel Pumps Add Q at given H

400

450

500IN PARALLEL

300

350

feet)

A

2A

3A

1 PUMP

200

250

Head (f B

2B 3B

C 2C 3C

1 ‐ PUMP

50

100

150

Maximum Static HeadAverage Static HeadMinimum Static Head1 Pump

C 2C 3C

3 ‐ PUMPSIN PARALLEL

0

50

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22Flow (mgd)

1 Pump2 Pumps3 Pumps

500

550

600

2A Series Pumps

Add H at Given Q

400

450

500

2B

300

350

feet)

A

2 ‐ PUMPSIN SERIES

200

250

Head (f A

B2C

50

100

150

Maximum Static Head

Average Static Head

Minimum Static Head

C

1 ‐ PUMP

0

50

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22Flow (mgd)

1 Pump in Series

2 Pumps in Series

Best Efficiency Point (BEP)

Preferred Operating Region (POR): 80% to 110% of BEP is ideal

PORAOR

110% of BEP is ideal Allowable Operating Region (AOR): 50% of 

BEPg ( )

BEP to runout is OK Brake Horsepower IMPELLER

SIZESPUMPEFFICIENCY % (BHP)

Net Positive Suction Head (NPSH)

SIZES EFFICIENCY %

Head (NPSH)

Water Horsepower 3960H)gpm(Q

550H)cfs(QWHP

Brake HP (pump input) Ep3960H)gpm(QBHP

Total HP (wire‐to‐water) EmEp3960H)gpm(QTHP

g = Specific Weight of Water (62.4 lb/ft3)l f fQ = Flow in cfs or gpm H = TDH (ft)

Ep = pump efficiency Em = motor efficiencyEp x Em = wire‐to‐water efficiency* If using VFD, wire‐to‐water efficiency = Ep x Em x Ed

C Cavitation Formation of vapor bubbles Drop below vapor pressure Loss of capacity, noise, vibration damage to pump

NPSH –TDH of fluid @ suction   f eye of pump

NPSHa – “Available”NPSH    H  H H H H NPSHa = Hbar + Hs – Hvap – Hf – Hm

NPSHr – “Required” NPSH    NPSH NPSHa > NPSHr

Insufficient NPSHa  = Cavitation

V i bl F  D i  (VFD)

500

550

600

Affinity Laws (N – rpm)

Variable Frequency Drive (VFD)

400

450

500

1 PUMP (100%)

Flow:2

1

2

1

NN

QQ

2NH

300

350

feet)

1 PUMP (100%)90%

80%

Head:2

1

2

1

NN

HH

311 NBHP

200

250

Head (f

70% Power:

2

1

2

1

NN

BHPBHP

50

100

150Maximum Static HeadAverage Static HeadMinimum Static Head1 PumpVFD@ 90%

0

50

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22Flow (mgd)

VFD @ 90%VFD @ 80%VFD @ 70%

V i bl F  D i  (VFD)

500

550

600 Variable Frequency Drive (VFD)

Advantagesh fl d d

400

450

500

1 PUMP (100%)

Match flow to demand Fewer yet larger pumps Reduced pressure surges

300

350

feet)

1 PUMP (100%)90%

80%

Reduced pressure surges Potential for lower operating 

costs

200

250

Head (f

70% Longer equipment life Reduced inrush current

50

100

150Maximum Static HeadAverage Static HeadMinimum Static Head1 PumpVFD@ 90%

0

50

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22Flow (mgd)

VFD @ 90%VFD @ 80%VFD @ 70%

V i bl F  D i  (VFD)

500

550

600

Disadvantages Higher capital / O&M costs

Variable Frequency Drive (VFD)

400

450

500

1 PUMP (100%)

Higher capital / O&M costs Increased equipment, larger 

electrical room

300

350

feet)

1 PUMP (100%)90%

80%

Less electrical efficiency Higher potential for vibration Heat dissipation

200

250

Head (f

70%

Heat dissipation

50

100

150Maximum Static HeadAverage Static HeadMinimum Static Head1 PumpVFD@ 90%

0

50

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22Flow (mgd)

VFD @ 90%VFD @ 80%VFD @ 70%

Horizontal Centrifugal End SuctionEnd Suction End suction, top discharge Wide variety of sizes Wide variety of sizes Low cost Most commonly  Most commonly manufactured pump

Many qualified Many qualified manufacturers

Horizontal Centrifugal Split CaseSplit Case Casing split axially Rugged  heavy duty Rugged, heavy duty High efficiencies Easy to maintain Easy to maintain Large footprint Bearings must be  Bearings must be protected from dust

Vertical Turbine –LineshaftLineshaft High head capability w/multiple stagesw/multiple stages

Tailor heads by adding bowls or stagesg

Installed in cans or sump Small footprintp Tight shaft tolerances

Vertical Turbine –SubmersibleSubmersible Submersible motor mounted at well bottom

No shafting or bearings above the bowl 

blassembly Quiet operation Practical at long depths Practical at long depths Frequent maintenance requires pulling unitq p g

Long electric cables

Design and Peak Flows, PressuresO ti   diti  &  t  h d  Operating conditions & system head curves

Select type, orientation & number of pumps Initial pump selection ‐ consult w/manufacturers Match pump and system curves Match pump and system curves Efficiencies, Horsepower, NPSH Performance curve analysis, operating points Capacity and/or Head increase optionsp y / p

k Raw Water Intake Located at lake or river Vertical configuration w/sump or cans is typical

B t  St ti Booster Station Horizontal or vertical configuration Installed along pipeline to boost pressure

High Service High Service Horizontal or vertical configurationI ll d   WTP Installed at WTP

Complicated hydraulics / system

Sump, Wet Well & Can design Piping & Valve design Piping & Valve design Pump control system (motor, drive  valves)drive, valves)

Power supply (main, standby) Instrumentation & SCADA HVAC & Ventilation Structural Design Architectural and LightingArchitectural and Lighting Site Design, Access, O&M

Pumping Station Design, 3rd Editionb  S k  T h b l  B by Sanks, Tchobanoglous, Bosserman

Pump Handbook, 4th Edition by Karassik, Messina, Cooper, Heald

Hydraulic Institute Standards (HIS)y ( ) AWWA ASTM ASTM ANSI

Any Questions??

David Bennett, P.E.Freese and Nichols, Inc.Freese and Nichols, Inc.San Antonio Office4040 Broadway Street Suite 600San Antonio, Texas 78209p 210.298.3800 f [email protected]