ENERGY RECOVERY OF HIGH PRESSURE

COLD INCOMING WATER IN DEEP LEVEL MINES

Presented by Danie le RouxAugust 2012

Conventional water reticulation of deep level mines

Opportunities for energy recovery

• Three Chamber Pump System (3CPS)• Displaces hot water with incoming cold

water• Consists of six high pressure and six low

pressure valves• Dissipater bypass system• Control system

How does a 3CPS work?

How does a 3CPS work?

How does a 3CPS work?

Principles of a 3CPS?

Control System of a 3CPS?

Opportunities for energy recovery

• Pump as Turbine (PaT)• Pump running in reverse• Powered through incoming cold water• Maintains back pressure• Generates electricity

Principles of a Pump as a Turbine

FT

MV1

MV1

CV1

CV1

MV2

MV2Existing PRVCONTROL VALVEMANUAL

VALVE

MAG-FLOW METER

REVERSE –RUNNING PUMP

HIGH PRESSURE

BYPASS LINE

VARYING DEMAND

Switch gear

Electricity at 50Hz

Conventional water reticulation of deep level mines

Ideal mine – all incoming pressure recovered

• Three x 3CPS being installed in Gold Mines (2 completed, 1 in process of completion)

• Eskom funded 50% • Payback to client reduced from 6 years to 3 years.

• Operating Specifications:• Designed flow rate 240 – 380l/s• Operating pressure 11 – 19MPa• Pump energy saving 3.5 + 4.3 + 5.8 = 13.6MW

Case Studies

Case Studies – 3CPS installed

Case Studies – Eskom site visit

• Significant opportunity to recover pressure of incoming cold water in deep level mines

• Higher Levels: a 3CPS or Pelton Turbine• Lower Levels: a PaT • There is no mine in SA where all the pressure

is currently recovered• Large savings are possible

Conclusion