Dry Ash Handling-presentation

7/31/2019 Dry Ash Handling-presentation

http://slidepdf.com/reader/full/dry-ash-handling-presentation 1/23



BURNING OF COAL IN A THERMAL POWER STATION

• Heat of coal generates steam in the Boiler which is fed to the steam

Turbine coupled with the Generator for ‘ GENERATION OF

ELECTRIC POWER’.

• It leaves behind huge quantities of residue called as ASH.



• FURNACE BOTTOM ASH

• ECONOMISER COARSE ASH• FLY ASH

TO

CHIMNEY

BOILER

BUNKER

BOTTOM ASH COARSE ASHFLY ASH

ESP+APH

HOPPERS

ECO

HOPPERS

MILLING SYSTEM



POWER GENERATION IN A THERMAL POWER STATIONIS DIRECTLY AFFECTED BY:

• The coal supply

• Ash Evacuation from the Boiler / Hoppers

•The Milling plant performance / Availability

•Main plant & auxiliary equipments performance/Availability



CLASSIFICATION OF ASH HANDLING SYSTEM

A) Operation duty• Operating Continuously

• Operating Intermittently

B) Method of Handling

• Wet Disposal System• Dry Disposal System

C) Means of Handling

•Pipe Lines

• Belt Conveyors

• Trucks / Mobile Equipments



TO REDUCE LAND & WATER REQUIREMENT

TO MINIMISE UNDERGROUND WATER & SURROUNDINGWATERWAYS POLLUTION

TO FACILITATE UTILISATION OF ASH IN BULK QUANTITIES



The fly ash is evacuated from fly ash hoppers & transported to ash

Storage Silos in two steps

> From the ESP & APH Hoppers to Buffer Hoppers throu

‘ VACUUM SYSTEM’.

> From Buffer Hoppers to ash storage Silos thro ‘PRESSURE

SYSTEM’.



TACs 1,2,3

FA LINES 1,2 TO ASH SILOs

BUFFER HOPPERS 1A/2A

VACUUM PUMPS

1A/2A

APH HOPPERS

A1

A7

A8

A14

FLY ASH ESP HOPPERS

PASS-ATOTAL ESP HOPPERS/PASS =28 NOs.

•EACH PASS HAVING 4 VAC LINES

•EACH VAC LINE HAVING 7 HOPPERS

•APH HOPPERS ARE CONNECTED TO

PASS B AND C



BUFFER HOPPER

Pr.COLLECTORSEC. COLLECTOR

TAC LINE # 1

TAC LINE # 2

VAC P/P

FROM ESP HOPPERS

BAG FILTERS

BHVIV

DASV

PCVEV

PCPEV

SCVEV

SCPEV

PCUDG

PCLDG

SCUDG

SCLDG

AIR LOCK TANKS

ALTUG ALTUG

ALTLGALTLG

FROM TAC LINESFROM TAC LINES

3-WAY V/V 3- WAY V/V

TO ESP DUCT



REAL TIME SEQUENTIAL OPERATION

T

I

MTIME (SEC) PCVEV PCPEV SCVEV SCPEV UDG LDG

0-60 OPEN CLOSE CLOSE OPEN OPEN CLOSE

65-125 CLOSE OPEN OPEN CLOSE CLOSE OPEN

ASH COLLECTION

(ESP HOPPERS TO BUFFER HOPPER VIA PR/SEC COLLECTORS)



OPERATION MODE

1. AUTO

MHV SELECTION MHV OPENING AND MHV CLOSING- ALL

OPERATIONS ARE PERFORMED IN AUTO DEPENDING ON

LINE VAC

2. MANUAL

MHV SELECTION IS WITH THE OPERATOR’S CHOICE

MHV SELECTION OPENING & CLOSING

LINE VAC 115 MMWC – SELECTED MHV CLOSING &

NEXT MHV SELECTION

LINE VAC 250 MMWC – SELECTED MHV OPENING



BUFFER HOPPER

TAC LINE # 1

TAC LINE # 2

AIR LOCK TANKS

ALTUG ALTUG

ALTLGALTLG

FROM TAC LINESFROM TAC LINES

3-WAY V/V 3- WAY V/V

TO ESP DUCT S/V



REAL TIME SEQUENTIAL OPERATION

REMOVAL OF ASH

(BUFFER TANK TO TAC LINES VIA AIR LOCK TANK)

TIME (SEC) 3-WAY Pr EQ. V/V ALTUG ALTLG

0-45 OPEN OPEN CLOSE

50-95 CLOSE CLOSE OPEN



FLY ASH EVACUATION – PROCESS (Contd.)

EACH UNIT HAS 4 BUFFER HOPPERS & TWO ASH TRANSPORT LINES.

ASH IS TRANSFERRED FROM VAC SYSTEM TO PRESSURESYSTEMWITH THE HELP OF PLCCONTROLLED UPPER GATE, LOWER.GATE & PRESSURE EQUALISING VALVES

EACH BUFFER HOPPER IS PROVIDED WITH PULSE JET CLEANEDBAG FILTERS TO SEPARATE ASH FROM CONVEYING AIR.



FLY ASH EVACUATION - PROCESS

FA HOPPERS ARE DIVIDED INTO GROUPS.

FA IS REMOVED FROM GROUPS IE ONE HOPPER FROM EACH GROUPSIMULTANEOUSLY IE ONE HOPPER FROM EACH GROUP AT A TIME.THRO’ PLC SYSTEM

VARYING LINE VACUUM IS USED TO CONTROL THE SYSTEM OPERATION

WHEN HOPPERS BECOME EMPTY VAC. FALLS AND THEN MHV CLOSES,

ANOTHER HOPPER IS SUBSEQUENTLY SELECTED.



A NO. OF PROTECTION / INTERLOCKS ARE PROVIDED FOR SYSTEM OPERATION.

3 SILOS FOR 2 UNITS OF 500 MW

SEG V/Vs LOCATED ON EACH SILO IN EACH FLY ASH TRANSPORT LINE ARE

USED TO CONTROL SILO SELECTION.

THE SYSTEM HAS PROVISION FOR STORAGE OF SEGREGATED ASH FROM ESP

HOPPER INDESIRED SILO FOR PURPOSE OF MEETING DIFFERENT REQMTS

FOR ASH SALE/UTILISATION.

SILO IS ALSO PROVIDED WITH BAG FILTERS, VENT FANS, HYDROMIX DUST

CONDITIONERSROTARY FEEDERS, AERATION BLOWERS ETC.



ASH STORAGE SILO

TAC LINES TAC LINES

HMDC

ROTARY FEEDERS

TO CLOSED TRUCKSTO OPEN TRUCKS

( CAPPACITY- 500 MT)

VENT FAN



FROM FAHP

FROM FAHP

FROM VAC P/P

FROM ESP HOPPERS

VIVs WHWV

ASH SLURY P/PS

WETTING HEAD

COLLECTOR TANK

WSV

WSV

WHWV

VBVB

ASH SLURY PIT



BOTTOM ASH / COARSE ASH EVACUATION

BOTTOM ASH EVACUATION SYSTEM:

BOTTOM ASH - WATER IMPOUNDED BA HOPPER- BOTTOM ASH GATE-- CLINKER GRINDER —

- HYDROEJECTOR- ASH SLURY LINES-- ASH SLURY PIT

> EACH BAH HAS TWO SECTION.

> EACH BAH HAS TWO OUTLETS.

> EACH OUTLET IS HAVING ONE BA GATE,ONE CLINKER GRINDER & ONE HYDROEJECTOR

> EACH UNIT IS HAVING TWO ASH SLURY LINES, BOTH OPERATING SIMULTANEOUSLY.

.> TOTAL 02 ASH SLURY PIT FOR TWO UNITS.

> BAH OVERFLOW- OVERFLOW TANK- OVERFLOW P/PS- SETTLING TANKS

> ECO HOPPER FLU. APPT ECO SLURY TANK ECO SLURY P/PS ASH SLURY PIT



ISOLATING GATE

ESPHOPPER

HP / LP

WATER

FLUSHING APPARATUS

SLURRY TO

ASH SLURRY PIT

ASH SLURRY PIT

GATE

GATE

ASH SLURRY LINES

TO ASH POND

STAGE # 1 ASH DISPOSAL SYSTEM

• EACH ESP HAVING 56 NOS OF HOPPERS

• THERE ARE 3 NOS OF ASH SLURRY PUMP HOUSES

• ONE PUMP HOUSE IS COMMON FOR TWO UNITS

• EACH PUMP HOUSE HAVING 3 SERIES OF ASH SLURRY PUMPS

• EACH PUMP HOUSE IS HAVING 3 NOS OF ASH DISPOSAL LINES

• ANY P/P CAN BE SELECTED FOR ANY ASH SLURRY LINE

LOW LIFT P/P

HIGH LIFT P/P

Dry Ash Handling-presentation

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