icue presentation - johnson g

8/7/2019 ICUE Presentation - Johnson G

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ICUE Conference Energy Efficient Motors Workshop

An Industrial Perspective ofSlurry Pumping Systems

Graeme Johnson

Paterson & Cooke Consulting Engineers (Pty) Ltd


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Presentation Overview

Where are slurry pumps used?

Examples of small and a large systems

Why do they consume so much power?

How can we reduce power consumption?


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Mining industry is main user of slurry pumps

In-plant process pumping relatively short distances

Ore or concentrate slurry pumping 10 to 500 km

pumping distance

Tailings (slimes) slurry pumping to deposition sites typically 1 to 10 km pumping distance (largest slurrypumping power consumer)


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Typical tailings pumping system

SLURRY TANK

TAILINGS DISPOSAL

SITE

PUMPS IN SERIES


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Typical tailings deposition site (dam)


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Example of small tailings pumping system

12 x 75 kW pumps (2 trains of 6 in series)


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Individual 75 kW slurry pump


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Slurry: Nickel tailings

Tonnage: 150 t/h

Volumetric flow rate: 190 m3/hPipe diameter: 170 mm

Pipeline length: 5800 m

Discharge pressure: 2700 kPa (26 bar)Number of pumps: 6 duty & 6 standby

Absorbed power: 330 kW


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Example of large tailings pumping system



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Slurry: Kimberlite slimes

Tonnage: 1570 t/h

Volumetric flow rate: 3640 m3/h

Pipe diameter: 450 mm


Discharge pressure: 2600 kPa (26 bar) Number of pumps: 12 duty & 6 standby



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Example of large PD pumping system

3 x 1500 kW pumps (2 operating, 1 standby)


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Example of large PD pumping system

Slurry: Kimberlite slimes

Tonnage: 610 t/h

Volumetric flow rate: 768 m3/h


Discharge pressure: 8 MPa (80 bar)

Motor rating: 1500 kW No of pumps: 2 duty, 1 standby



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Slurry pumping is basically an inefficient way oftransporting solids, but very convenient

Large flow rates

Long pumping distances

Must pump at high velocity high pipeline friction

Viscous slurries high pumping pressures .


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Example of a Viscous Slurry

m=1.56


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Pump efficiency reduced due to solids de-rating

Robust pump impeller design - low efficiency

Efficiency drop-off due to wear of pump impellers

Normally belt or gearbox speed reduction drive losses

Variable pumping duty ..


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Variable pumping duty

Varying flow rate

Pumping distance varies Not all pumps operate at all times wind milling

SLURRY TANK

TAILINGS DISPOSAL

SITE

PUMPS IN SERIES


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Mind shift required capital costs vs operating costs

Traditionally in SA capital cost was minimised at theexpense of operating costs (low power cost and highcost of capital)

Each pumping system must be carefully designed &optimised for specific application


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Normally power consumption reduction will involve extracapital cost

Rule of thumb design procedures often result ininefficient systems

Regular maintenance ensures maximum pumpefficiency


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icue presentation - johnson g

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