Possible Routes for Possible Routes for

Beneficiating High Ash Indian Beneficiating High Ash Indian

Coals for Thermal Power Coals for Thermal Power

StationStationByBy

Kalyan SenKalyan SenCentral Fuel Research Institute,

Dhanbad, India

Kalyan senKalyan sen

Characteristics of Indian CoalsCharacteristics of Indian Coals

Favorable Qualities: Low sulfur Content

(<0.6%) High AFT ( >1100 oC) Low iron content Low Cl2 content (<0.1%)

Low toxic trace elements High reactive inertinites

Constrains:Genetic:• High inertinite content• High moisture content

Operational:Mechanised mining in large OCP

Organizational:Multiple sources/Linkages

Beginning Beginning of the conscientious effort :of the conscientious effort :

Coalfield Year Cap (Mty) Linkage

Singrauli 1997 4.5 Dadri

Korba 1998 2.5 Dhanu

S.Karanp 1999 2.5 -

Jharia 1999 1.0 -

E.Bokaro 1999 2.7 -

IP6.51997N.Karanp

Washery

Bina, NCL

Dipika, BSES

Piparwar, CCL

Converted

Gidi, CCL

Dugda I, BCCL

Kargali, CCL

Kalinga (8.0 Mty) at Talcher : coming Kalinga (8.0 Mty) at Talcher : coming

washerieswasheries

Identified Barriers For Beneficiation of Indian Non-coking Coal

•Economic Barrier

•Policy Barrier

•Technological Barrier

barriersbarriers

parameters to be considered Characteristics ash value < 50 - 55% Heat value Petrographic reactives

Optimum Beneficiation Optimum Beneficiation StrategyStrategy

The beneficiation strategy should focus not on maintaining a prefixed overall ash limit but on restricting the non-combustibles to an optimally minimum level corresponding to the limiting quality parameter/s

0

10

20

30

40

50

60

70

80

90

1.30 1.40 1.50 1.60 1.70 1.80 1.90 2.00

Relative Density

Cha

ract

eris

tic

Ash

% 50-55%

d 50

Range of cut density (d50 ) for power grade cleans from Indian noncoking coals

Characteristic Ash

Characteristic Ash

Level Scheme Methodology Ash%reducn

Cleans (%)

M % over ROM coal

I Dry benefin. Separation of stone/shale based on differential breakage potentiality

3-4 >90 Nil

IICrushing, screening & coarse coal cleaning

Coarse coal (13/30mm) washed & mixed with untreated fines; dewatering screens.

<10 70-90 2-3%

IIICrushing, screening and total cleaning

Coarser fraction washed at optimum efficiency levels: fine coal by Spiral: dewatering

>10 <60 3-4%

Possible beneficiation schemes for power coal  

routesroutes

0

20

40

60

80

100

20 25 30 35 40

Ash %

Yie

ld %

Theoretical RotaryBr.

HM washerIm 0.08

Batac JigIm 0.12

Baum JigIm 0.18

WocIm 0.2 **

Predicted yields of Cleans at different washers for a non-coking coal (100-3mm, Ash 41.0 %)

** Raw coal crushed to 25 mm (25-3mm), ash 40.8%

pred-yieldpred-yield

CONCLUSION:

Improvement of the overall efficiency and

environmental performance of the coal-

energy chain demands

• beneficiation of Indian coal as an integral

component for thermal power generation

• proper identification and removal of the

barriers that act against implementation of

the coal washing strategyContinued….

• modification/ modernisation of the existing

washeries or installation of new washeries with

improved process design in view of changed

feed characteristics of the ‘difficult-to-wash’

coals.

• beneficiation strategy based on some intrinsic

quality parameters that guarantee the

presence of desired reactive combustibles in

the product.

CONCLUSION:

Thank Thank youyou

Beneficiation of Indian non-coking coal appears to be the best option, if not a bare necessity for achieving quality consistency of the supply to TPS and subsequent improvement in cleaner energy production.

Economic Barriers

From producers’ point of view:•Additional cost of washing•Shortfall in target supply at the desired

level of quality parameters•Present system of grading and pricing of coal•Resource constraints for coal companies

Contd…..

economiceconomic

Economic Barriers

From users’ point of view:

• Reluctance to enter into commercially enforceable agreement

• Additional cost of washing• Lack of appreciation of benefits of washing • Availability of cheaper imported coal at port site • Lack of ineterest by SEB’s for setting up new

washeries

economic2economic2

Policy Barrier

•Present regulatory framework that needs

to be reviewed as investor-friendly

•Lack of proper ambience for inviting

private investors

•Imbalance due to existing duty structure

•Existing system of coal linkages

policypolicy

Technological Barrier

• Difficult to wash coal: need costlier deep beneficiation• Suitable washing scheme for desired

products• High moisture content, 6-10%• Loss of coal in Washery rejects• No suitable techno-economic outlet for

rejects

tech-barrierstech-barriers