1

WET ASH SYSTEMWET ASH SYSTEMDate 14 August 2008

2

CONTENTSCONTENTS

1. Background

2. Ash plant design

3. Type of ash systems

4. Wet Ash System overviewi. Layoutii. Operating Philosophy

5. Technical data

6. Wet ash Hydrovacs

7. Wet ash pumps

8. Ash pipelines

9. Disposal of wet ash

10. Ash dams area

11. Ash water return dams

12. Protections and safety precautions

13. Conclusion and Recommendation

3

BACKGROUNDBACKGROUND

Ash is non-combustible

material in coal

Types of ash created

during combustion

- Coarse Ash (10%)

- Fly Ash (90%)

Disposal of ash

4

ASH PLANT DESIGNASH PLANT DESIGN

Plant geographic position

Environmental regulation

Size of the power plant

Market of by-product

5

TYPE OF ASH SYSTEM IN ESKOMTYPE OF ASH SYSTEM IN ESKOM

Wet Ash Systems

- Water is the primary ash transport medium

-Use excessive water consumption

Dry Ash Systems

-Semi dry with conveyor belts used for transportation

6

WET ASH SYSTEM OVERVIEWWET ASH SYSTEM OVERVIEW

7

TECHNICAL DATATECHNICAL DATA

Sluice Pump Motor 3.3 kV

Sluice Pump Capacity 1020m³/hour

Sluice Pump Pressure 1500kPa

Ash Sump - Coarse Ash 850tons/day

Ash Sump - Fly Ash 3400tons/day

Ash Dam Capacity 1500tons/day

Ash Water Return Pump (x8) 22.5m³/min (each)

Booster Pump Capacity 55.3m³/min

8

WET SYSTEM HYDRO-VACWET SYSTEM HYDRO-VAC

Mechanical agitator

Ash inlet

To ash sump

Pressure gauge

Water inlet

9

WHEN HYDROVAC IS BLOCKEDWHEN HYDROVAC IS BLOCKED

10

WET ASH PUMPWET ASH PUMP

Motor

Discharge

Suction

11

ASH AND WATER PIPELINESASH AND WATER PIPELINES

Ash pipes

Water return pipes

12

DISPOSAL OF WET ASHDISPOSAL OF WET ASH

EvaporationPipeline from Power Plant

Ash Dam

13

ASH DAM AREAASH DAM AREA

14

ASHASH WATERWATER RETURN DAMRETURN DAM

15

PROTECTIONSPROTECTIONS

Ash Sump Levels

- Trip Ash pump < 1.25m

- Start Ash pump > 3.9m

- High sump Level alarm >4.5m

- Trip sluice pumps > 4.5m

Ash Pump

- Bearing high temp alarm < 75ºC

- Bearing high temp trip > 85ºC

16

SAFETY PRECAUTIONSSAFETY PRECAUTIONS

• Safety Equipment:

- Gumboot,- Safety gloves, Dust mask,

- Overalls, Ear protection and Hard hat

• No standing in front of hoppers

• Ensure ash hopper outer door is shut

• Ensure sluice way nozzles are working

17

CONCLUSION AND RECOMMENDATIONCONCLUSION AND RECOMMENDATION

Environmental impact

Pipeline wear rates investigation

18

PIPELINE WEAR FACILITYPIPELINE WEAR FACILITY

19

RECOMMENDATIONRECOMMENDATION

20

THANK YOUTHANK YOU

QUESTIONS???