fine coal beneficiation
TRANSCRIPT
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