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Center for Advanced Separation Technologies CASTCAST
COST EFFECTIVE TECHNOLOGY
FOR BENEFICIATION AND RECOVERY OF FINE COAL
Roe-Hoan Yoon, Director
Center for Advanced Separation Technologies
Virginia Tech, Blacksburg, Virginia 24060
Presented at:
U.S.-India 6th Coal Working Group Meeting
L’Enfant Plaza Hotel, Washington, D.C.
September 23, 2009
Center for Advanced Separation Technologies CASTCAST
Indian Coal
� Problem� Difficult to clean
• Finely disseminated mineral matter
� Coking coal requires low ash coal• <8% ash
• Imported coal is used as sweetener– High cost
� Solution� Fine grinding for improved
liberation
� Fine coal cleaning
� Fine coal dewatering 2 mm
Center for Advanced Separation Technologies CASTCAST
0
20
40
60
80
100
0 6 12 18 24 30
Product Ash (%)
Co
mb
usti
ble
Reco
very
(%
)
28 x 100 mesh
-100 mesh
-325 mesh
Release Analysis
Assam Coal I
Fine coal produces lower-ash coal.
Center for Advanced Separation Technologies CASTCAST
But fine coal cleaning is costly and difficult.But fine coal cleaning is costly and difficult.
SieveBends
Dense Media
Cyclone
BasketCentrifuges
Dense Media Vessel
DewateringScreens
Raw CoalScreens
Coal Spirals Screen-BowlCentrifuges
ClassifyingCyclones
Med
ium
Solid-Solid Solid-LiquidSize-SizeC
oar
seF
ine
Ult
rafi
ne Froth Flotation Disc Filter
Increasing Difficulties
Increasing Difficulties
Center for Advanced Separation Technologies CASTCAST
Advanced Fine Coal Cleaning Technologies
Developed at Virginia TechUnder DOE Sponsorship
� Advanced Flotation� Microcel technology� New FLS technology
� Advanced Dewatering� Dewatering aids
• Licensed to Nalco
• Pinnacle pond recovery
� Hyperbaric centrifuge• Licensed to Decanter
• Field tests are ongoing
All of the technologies are commercially available.
Center for Advanced Separation Technologies CASTCAST
Bubble Generation in Microcel
MicrocelSpargers
Pump
In-LineMixer
BubbleGenerator
MicrocelSpargers
Pump
In-LineMixer
BubbleGenerator
MicrocelSpargers
Pump
In-LineMixer
BubbleGenerator
Center for Advanced Separation Technologies CASTCAST
Microcel Column InstallationRed Mountain (BHP Billiton)
Center for Advanced Separation Technologies CASTCAST
Advanced Flotation
Pilot-Scale Test Unit Installed at Virginia Tech
World’s largest and most efficient flotation machine
(located at Kennecott).Simulation of fluid flows using Computational Fluid
Dynamics (CFD)
Center for Advanced Separation Technologies CASTCAST
Dewatering AidComparison of Lab and Plant data
Center for Advanced Separation Technologies CASTCAST
Hyperbaric Centrifuge
� Pilot-scale tests
� Moisture reduction
• ≈50% using conventional filter
• 13.4% using hyperbaric
centrifugation.
• >97% recovery on a coal with
90% -325 mesh
� Marketed by Decanter Machine Inc.
Mobile Test Rig for Field Demonstration of the New
Hyperbaric Technology
Testing at Arch Coal’s Cardinal Preparation Plant in Southern West Virginia
Center for Advanced Separation Technologies CASTCAST
Proposed Flowsheetfor Indian Coking Coal
Slurry
Feed
Note: Not all
clarified and
process water
streams are
shown.
Existing
Plant
Column
Flotation
Waste
Four-Stage
Conditioner
Thickener
Disc Filter
Clean Coal
Filtrate
Pump
Vacuum
Receiver
Vacuum
Pump
Conveyor
Sparger
Compressor
Rotary
Distributor
Classifying
Cyclones
O/F
PumpU/F
PumpFeed
Sump
Rod
Mill
Center for Advanced Separation Technologies CASTCAST
Summary
� India can increase the domestic production of coking coal.
� fine grinding to improve liberation,
� advanced flotation to remove ash, and
� advanced dewatering to remove moisture.
� Advanced technologies:
� Microcel flotation
� Novel dewatering aids
� Hyperbaric centrifugation
� Demonstration plant
� 75 -100 tonnes/hour
� Virginia Tech design
� Contract is being negotiated.