FINE COAL BENEFICIATION

Roe-Hoan Yoon, DirectorCenter for Advanced Separation Technologies

Virginia Tech, Blacksburg, Virginia 24060

U.S.-India Coal Working Group8th Annual MeetingNew Delhi, IndiaMarch 24, 2011

2

Indian Coal

ProblemMineral matter is finely disseminated in coal matrixDifficult to obtain low-ash product

• Causes low thermal efficiency in power plants

• Requires sweetener for metallurgical application

>$3 billion import

SolutionFine grinding for liberation of mineral matter

• Fine coal cleaning• Fine coal dewatering

2 mm

3

Finer coal produces lower-ash coal.

0

20

40

60

80

100

0 6 12 18 24 30

Product Ash (%)

Com

bust

ible

Rec

over

y (%

)

-100 mesh-325 mesh

Release AnalysisAssam Coal II

4

Another Example

0

20

40

60

80

100

0 6 12 18 24 30

Product Ash (%)

Com

bust

ible

Rec

over

y (%

)

28 x 100 mesh-100 mesh-325 mesh

Release AnalysisAssam Coal I

5

But fine coal cleaning is difficult and costly.

SieveBends

Dense Media

Cyclone

BasketCentrifuges

Dense Media Vessel

DewateringScreens

Raw CoalScreens

Coal Spirals Screen-BowlCentrifuges

ClassifyingCyclones

Med

ium

Solid-Solid Solid-LiquidSize-SizeC

oars

eFi

neU

ltraf

ine Froth Flotation Disc Filter

Incr

easi

ng D

iffic

ultie

sIn

crea

sing

Diff

icul

ties

6

Middle Fork, Virginia

Then…Coal industry discards fine coal Impoundment

• ~2-2.5 billion tons in the U.S.Underground injection

MicrocelTM Technology developed at CAST

>$50 million profit from one pond

…and Now

Microcel Technology

7

Microcel Technology in Australia Licensed to Eriez

Red Mountain (BMA)

The technology is used to recover coal in operating plants.

8

Moura Dawson (Anglo Coal)

9

A missing link

ash/sulfur

Fine CoalCleanCoal

water

WaterFlotation

Dewatering

?

10

Dewatering Aid TechnologyLicensed to Nalco Company

0 5 10 15 20 25 30 35 400

3

6

9

12

15

18

21

24

27

30

Vol

ume

(cm

3 )

Time (sec)

Base Line100 g/ton Flocculants1 lb/ton Dewatering Aid2 lb/ton Dewatering Aid3 lb/ton Dewatering Aid5 lb/ton Dewatering Aid 17

19

21

23

25

27

0 0.50 1.00 1.50Reagent Dosage (lb/t)

Cak

e M

oist

ure

(%)

LaboratoryIn-Plant

Pinnacle impoundment, WV

11

Hyperbaric Centrifuge TechnologyLicensed to Decanter

Screen-bowl Centrifuge

Hyperbaric (or CentrabaricTM) Centrifuge

12

Commercial Installation

Jim Walter Resources(Walter Energy Inc.)

Brookwood, Alabama

As a result of successful test results with the first unit, the company bought more units. Other companies may follow the suite.

13

Proposed Flowsheet for Indian Coking Coal

SlurryFeed

Note: Not all clarified and

process water streams are

shown.

ExistingPlant

ColumnFlotation

Waste

Four-StageConditioner

Thickener

Disc Filter

Clean Coal

FiltratePump

VacuumReceiver

VacuumPump

Conveyor

SpargerCompressor

RotaryDistributor

ClassifyingCyclones

O/FPumpU/F

PumpFeedSump

RodMill

14

Summary

CAST technologiesCommercially available technologiesMicrocelTM, Dewatering aids, Hyperbaric centrifugeA novel dewatering technology

Under development

Proposed workTo design and build a 75-100 tph fine coal beneficial plantMETSO Minerals-India, Prime

Engineering Construction

Virginia Tech, SubcontractorLab workFlowsheet design

BenefitsIncrease domestic supply of metallurgical coal

Decrease import of metallurgical coalImprove coal quality and reduce CO2 emissions

15

Acknowledgement

The National Energy Technology Laboratory for financial supportLicensees of the technologies developed at CAST

Metso MineralsEriez ManufacturingNalco CompanyDecanter Machine Company