design and testing of new centrifugal pump design for bitumen froth applications

The Design and Testingof a

New Centrifugal Pump Designfor

Bitumen Froth Applications

Presentation for the Calgary Pump Symposium, Nov. 13, 2009

© 2009 GIW Industries Inc.R. Visintainer / Nov-2009

Froth and ViscousFroth and ViscousLossesLoss s

© 2009 GIW Industries 2 R. Visintainer

Bitumen Froth Losses – Head (Pressure)

Summary of the primary losses in viscous froth and h f ff i h

Clear water: pump d i & d

the factors affecting them.

design & speed.

Viscosity effect: bitumen properties, temperature.

Density effect: % air.

Airlock: % air viscosityAirlock: % air, viscosity, froth properties, flowrate, system & pump design.

© 2009 GIW Industries 3 R. Visintainer

Bitumen Froth Losses – NPSHR




design & speed.



Airlock: % air viscosityAirlock: % air, viscosity, froth properties, flowrate, system & pump design.

4 R. Visintainer© 2009 GIW Industries

Strategies for Improving Froth Pump Performance

Improve suction inlet conditions:Increase NPSHA

Improve suction inlet conditions:Increase NPSHAIncrease NPSHADecrease % airIncrease pump inlet diameter

Increase NPSHADecrease % airIncrease pump inlet diameter

Increase pump head without increasing speed:Increase impeller diameterHigh head impeller design

Increase pump head without increasing speed:Increase impeller diameterHigh head impeller design

Control airlock:Adjust froth properties

Control airlock:Adjust froth properties

Focus of this research project.

Prevent (or delay) airlock formationAirlock ventingPrevent (or delay) airlock formationAirlock venting

5 R. Visintainer© 2009 GIW Industries

T t S tTest Setup

© 2009 GIW Industries6 R. Visintainer

Froth Test Rig – GIW Hydraulic Lab


Froth Test Rig – Sparger Design


Froth Test Rig – Clear Suction Spool


Froth Test Rig – Testing Parameters

• Viscosity:

o 1 cSt (water)

o 500 to 10,000 cSt (corn syrup)

• Air: 0% to 30%

• Flow: 1000 – 3000 m3/hrFlow: 1000 3000 m /hr

• Head: 10 to 60 m

• Speed: 300 to 800 rpm

• Suction pressure: 0.0 to 1.0 atm


Ai l kAirlock


Airlock – Low Re Number (laminar)

Airlock forms as elongated bubble in suction piping.


Airlock – High Re Number (turbulent)

Notice density difference between froth in impeller p

passages and casing. Also formation of airlock

bubble in suction.


Airlock – Some Typical Results

airlock


“Excess Air” Concept – Suction Inlet Coalescence

Onset of airlock coincides with appearance of coalesced air in

suction piping.


Strategies for Controlling Airlock

Adjust froth properties:Decrease % air in the process

Adjust froth properties:Decrease % air in the processIncrease suction inlet velocity (works against improved NPSHR)Prevent “excess” air from reaching the suction inlet (i d d i f d l d )

Increase suction inlet velocity (works against improved NPSHR)Prevent “excess” air from reaching the suction inlet (i d d i f d l d )(improved design of sumps and launders)

Prevent (or delay) airlock formation:Airlock disturbance (open shrouded designs)

(improved design of sumps and launders)

Prevent (or delay) airlock formation:Airlock disturbance (open shrouded designs)Airlock disturbance (open shrouded designs)Improved NPSHR performanceHigh head impeller design

Airlock disturbance (open shrouded designs)Improved NPSHR performanceHigh head impeller design

Focus of this research projectAirlock venting:

Suction inlet venting (removes coalesced air) Internal pump venting

Airlock venting:Suction inlet venting (removes coalesced air) Internal pump venting

Focus of this research project.

Internal pump ventingInternal pump venting


Airlock Venting System



PSUCTION > PVENT

excess air

excess air

Suction pressure must exceed vent pressure (usually atmospheric) by at least 10 kPa

froth

excess air

froth



Vent pipe: Use hard pipe with heat strips in bitumen applications.


Airlock Venting System – Some Typical Results

vent closed, typical airlock losses

vent opened,airlock losses controlled


Airlock Venting System – Some Typical Results


Airlock Venting System – Viscous Froth

OPERATION OF AIR VENT - AIR LOCK REMOVAL500-700 rpm, 3000 m3/hr, corn syrup at approx 3,000 cSt, 15% air plus 5% excess air added at sparger

Airlock venting


High HeadHigh HeadImpeller Designp g


High Head vs. Conventional Designs




design & speed.



Airlock: % air viscosityConventional design(without venting) Airlock: % air, viscosity,

froth properties, flowrate, system & pump design.

( g)



Advantage of High Head design operating at same

d d NPSHR


speed and NPSHR.

design & speed.

Viscosity effect: bitumen properties,

Hi h H d d i

High Head design(with venting)

temperature.


Airlock: % air viscosity

High Head design(without venting)

Airlock: % air, viscosity, froth properties, flowrate, system & pump design.


High Head Impeller Design – CFD Analysis

CFD analysis used to optimize NPSHR

fperformance.

HIGH SUCTION SIDE VELOCITY@ DESIGN FLOWRATESHOCKLESS ENTRY

NEGATIVE NPSHR IMPACT



Turbulence helps to disturb airlock formation

Conventional Closed Shroud Design Expanded, Open Shrouded Design



Higher head = more gas compression

Expanded, Open Shrouded DesignConventional Closed Shroud Design



Some sacrifice in Efficiency

Increased Head

Improved NPSHR at higher flows


High Head Impeller NPSHR Performance

V i bl d NPSHR t tiVariable speed NPSHR testingWater froth - 0.03% soap

100% BEPQ600 - 810 rpm


Viscous Viscous Effects


Viscous Froth Simulation

Corn syrup at 3,000 cSt


Viscous Froth Simulation

Corn syrup froth at 15% air and 3,000 cSt


Viscous Testing and Analysis – Typical Results

Viscosity Correlations

HEAD

1 000 to 10 000 cSt1,000 to 10,000 cSt10-15% air

0% excess air0.05 to 0.1 atm Psscaled to 700 rpm




FLOW

1 000 to 10 000 cSt1,000 to 10,000 cSt10-15% air




Viscosity CorrelationsEFFICIENCY

1 000 to 10 000 cSt1,000 to 10,000 cSt10-15% air





POWER

1 000 to 10 000 cSt1,000 to 10,000 cSt10-15% air



KeyKeyLearningsg


Key Learnings

• Given enough air, the pump will airlock.

• The “Excess Air” concept:• The Excess Air concept:

Airlock occurs when the liquid is carrying more air than it can hold.

For conventional designs in clear water: 3% to 5%.

Depending on composition of froth, can increase to 40% or more.

• Airlock can be delayed by…

… airlock venting systems (requires suction pressure > atmospheric).

… high head impeller designs adjusted for good NPSHR performance.

Hi h h d i ll d i i f th f b• High head impeller design can improve froth pump performance by…

… reducing operating speed thus improving NPSHR performance.

… more airlock disturbance.

… better air compression within the impeller.


Questions&

DiscussionDiscussion


design and testing of new centrifugal pump design for bitumen froth applications

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