Simplified & High Efficient Coal Process Technology For Mongolian Coal
Jimmy YuVP, Ph.D, PEng.
Tangshan Guohua Technology Corporation
Beijing Guohua Technology Group
Tangshan, Heibei, China 063020
BEIJING GUOHUA TECHNOLOGY GROUP
OUTLINE
Characteristics of Mongolia Coal
Simplified & Highly Efficient HM Process Technology
Conclusions
Introduction
Advanced fine coal slurry treatment circuits
Advantages of the new HM Process Over Traditional Process
INTRODUCTION
Most of coals in North America are easy to wash.
Clean coal yield & recovery is usually low using conventional processing technologies to process difficulty-wash coalHigh efficient and simplified process technologies are needed to develop to recover more clean coal and to save capital & operating costs at the same time.
However, most of coals in China and some of Mongolia coals are difficult to wash or require high separation density.
Characteristics of Mongolian Coal
One Example of Mongolian Coking Coal Samples
Either 1) To produce clean coal ash content at 8%, separation density required is over 1.9 kg/L, or 2) Produce low ash clean coal at 5.5% with 1st stage separation density 1.45 and middling
at 23% ash with 2nd stage separation density 1.9 and pure rejectOr 3) Combine clean coal and middling as final clean coal at ash content of 8% and pure reject.
PROBLEMS WITH TRADITIONAL PROCESS FOR DIFFICULTY-WASH COALS
Circuit is complicated with a lot of equipment involved
A large amount of secondary coal fines generatedduring washing process
High Capital investment and high operating cost
Low separation efficiency at high separation density
Complicated and costly circuit for fine coal treatment
PROBLEMS WITH TRADITIONAL PROCESS FOR DIFFICULTY-WASH COALS
North America
Spiral
Cyclone Derrick
Deslime screen
Sizing screen
H.M. Drum
W.O. cyclone
Classifying cyclone
Slurry pumped outside plant
Spiral feed pump tank
Classifying cyclone feed pump tank
Classifying cyclone
Classifying cyclone
What Is Simplified & High Efficient HM Process ?1.1
Typical New Heavy Medium Flowsheet
SIMPLIFIED & HIGHLY EFFICIENT HM PROCESS SOLVES THE PROBLEMS
Raw coal
3-product H.M. cyclone
Middlings sieve bend
Clean coal sieve bend
Circulating water
Clean coal H.M. drain, rinse& classifying screen
Fine coal H.M. cycloneMiddlings H.M. draining & classifying
screen
Reject HM draining screen
Reject
Reject magnetic separator
Centrifuge Middling magnetic separator
Clean coal magnetic separator Centrifuge
Flow spilter
Flow spilter
Raw coal H.M. tank Middlings Clean coalTo clean fine
sieve bendTo 1st stage thickener
Rejects
Middlings Clean coal
Raw coal
3-product H.M. cyclone
Clean coal sieve bend
Circulating water
Clean coal H.M. D & R& classifying screen
Reject D&R
screenReject
Reject magnetic separator
Clean coal magnetic separator
Centrifuge
Flow spilter
Raw coal H.M. tank
Clean coal
clean fine sieve bend
Rejects
Clean coal
Clean coal
1st stage thickener
Fine coal H.M. tank
Reject D&R
screen
Typical Thermal Coal HM Process Circuit uisng Gravity-fed non-desliming 3-product cyclone
ADVANTAGES OF NEW HM PROCESS OVER TRADITIONAL PROCESS
1. The new HM process with non-desliming significantly simplifies HM process using less equipment (without desliming screens, hydro-cyclone, spirals, TBS and etc.) and smaller plant space required, which results in lower capital investment
2. Gravity-fed reduces secondary coal fines generation considerably
3. Lower operating cost due to simple process, less equipment & much higher separation efficiency than traditional processes
4. Using low single density HM suspension to achieve stable high separation density
5. Much higher clean coal yield due to higher separation efficiency compared to traditional HM process especially for high ash and difficulty-washing coal or when requiring high separation density
ADVANTAGES OF NEW HM PROCESS OVER TRADITIONAL PROCESS
1. The new HM process with non-desliming significantly simplifies HM process using less equipment (without desliming screens, hydro-cyclone, spirals, TBS and etc.) and smaller plant space required, which results in lower capital investment
PROBLEMS WITH TRADITIONAL PROCESS FOR DIFFICULTY-WASH COALS
North America
Spiral
Cyclone Derrick
Deslime screen
Sizing screen
H.M. Drum
W.O. cyclone
Classifying cyclone
Slurry pumped outside plant
Spiral feed pump tank
Classifying cyclone feed pump tank
Classifying cyclone
Classifying cyclone
ADVANTAGES OF NEW HM PROCESS OVER TRADITIONAL PROCESS
2. Gravity-fed reduces secondary coal fines generation considerably
Industrial plant tests indicate: The secondary slime generated during washing process
with gravity-fed H.M. cyclone is 5~7 percentage points (in total feed) less than that
produced during process with pressurized feeding cyclone. It is very important and
beneficial to the design of thermal coal plant.
Pump feed Gravity feed Difference
Slurry Volume (m3/h) 700 700
Solid Content (g/L) 135 102
Amt of -0.5 mm (t/h) 94.5 71.4 32.4%
Test at Linhuan Plant: Difference of Amount of -0.5 mm Fines between Gravity-fed & Pump-fed
※ Each cyclone feed rate: 302 t/h
ADVANTAGES OF NEW HM PROCESS OVER TRADITIONAL PROCESS
3. Lower operating cost due to simpler process, less equipment, & much higher separation efficiency (higher centrifugal force and lower separation size limit) than traditional processes
• Higher centrifugal force: HM suspension feed pressure is double the traditional HM process (17 times of cyclone diameter instead of 8 times)
• Lower separation size limit: effectively separate coal particle size down to 0.25 mm in the 3-product cyclone and down to 0.1 mm in fine coal HM cyclone
0.5~0.25 mm 0.099kg/L
588~606 t/h,
0.1~0.074 mm 0.08 kg/L No ultrafine magnetite needed
588~606 t/h,
> 0.5 mm (I) 0.02-0.025 (II) 0.025-0.045
Coal Size Fraction Epm Value Throughput Capacity
ADVANTAGES OF NEW HM PROCESS OVER TRADITIONAL PROCESS
3. Lower operating cost due to simpler process, less equipment, & much higher separation efficiency (higher centrifugal force and lower separation size limit) than traditional processes
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2
Coal feed particle size (mm)
Ep Value
Spiral
TBS
GTC H.M. Cyclone
0.060.07
0.120.123
0.225
0.275
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2
Coal feed particle size (mm)
Ep Value
Spiral
TBS
GTC H.M. Cyclone
0.060.07
0.120.123
0.225
0.275
The Performance (Ep Values) ofSpiral, TBS & HM Cyclone VS. Coal Size
Reference: “Performance of the Teetered Bed Separator at the Murray Energy Century Preparation Plant”- Paper published in Coalprep 2009 Kentucky
ADVANTAGES OF NEW HM PROCESS OVER TRADITIONAL PROCESS
4. Using low single density HM suspension to achieve stable high separation density
Raw feed
Clean
Heavy medium
Middling
Reject
s.g./1.4
s.g. 1.8
E.g.,
Heavy medium
Vortex finder Apex
ADVANTAGES OF NEW HM PROCESS OVER TRADITIONAL PROCESS
5. Much higher clean coal yield due to higher separation efficiency compared with traditional HM process especially for high ash and difficulty-washing coal requiring high separation density
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2
Coal feed particle size (mm)
Ep Value
Spiral
TBS
GTC H.M. Cyclone
0.060.07
0.120.123
0.225
0.275
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2
Coal feed particle size (mm)
Ep Value
Spiral
TBS
GTC H.M. Cyclone
0.060.07
0.120.123
0.225
0.275
Raw coal
HM
Clean coal Middlings
Reject
1st Stage HM 2nd Stage HM
1.851.45 D
ensi
ty
Den
sity
Time Time
1) Unstable separation density with traditional process
2) Higher separation efficiency for fine coal fraction
Magnetite Consumption★
< 1.0 kg/t at many normal circumstances in the plants designed by
TGTC using gravity-fed non-deslime 3-product H.M. Cyclone
process;
For example, 0.55 kg/t in Wenfeng plant
0.51kg/t in Tianwei plant
since the plants were operated.
ADVANTAGES OF NEW HM PROCESS OVER TRADITIONAL PROCESS
ADVANCED FINE COAL SLURRY TREATMENT CIRCUIT
Clean Fine Circuit:(Coking coal)
2-Stage Flotations & 2-Stage Dewatering
Tailing�from�cleancoal�magnetic�separator
Filtrate�as�wash�water
Filter�press
Flotation�cells
Clean�fine�sieve�bend
Screen - bowl�centrifuge
The�buffer�tank/pump�for�flotation
Flotationcells
Flotation�concentrate�tank/pump
Filtrate
Tailing�from�cleancoal�magnetic�separator
Filtrate�as�wash�water
Filter�press
Flotation�cells
Clean�fine�sieve�bend
Screen - bowl�centrifuge
The�buffer�tank/pump�for�flotation
Flotationcells
Flotation�concentrate�tank/pump
Filtrate
Coarse fine circuit
Coarse fine circuit
Fine circuitFine circuit
Fine Tailings Circuit: 2-Stage Thickening & 2-Stage Dewatering
Coarse fine circuit
Coarse fine circuitFine circuitFine circuit
ADVANCED FINE COAL SLURRY TREATMENT CIRCUIT
OUTLINE
Conclusions
Majority of Chinese and some of Mongolia coals contain high ash,belong to difficulty-washing coals, or/and require high separationdensity during the process
The new HM process, using gravity-fed non-desliming 3-productcyclone, has been extensively used in more than 450 coal preparationplants in China (98 plants in Inner Mongolia) with completely close-circuit operation, will be suitable to Mongolia coal
Based on the large amount of industrial proven data, using the newdeveloped HM process will be expected to significantly increase cleancoal yield when used in Mongolia coal industry due to its much highseparation efficiency. Simultaneously, capital investment & operatingcosts can be considerably reduced by 20~40 %.
CONCLUSIONS
TANGSHAN GUOHUA TECHNOLOGY CO., LTD.
Mixed, non-deslimed gravity-fed 3-product heavy medium cyclone technology
Gravity-fed 3-product H. M. cyclone
DEVELOPMENT OF TECHNOLOGIES AND EQUIPMENTGravity-fed 3-product H.M. cyclone
Mixed, non-deslimed gravity-fed 3-product heavy medium cyclone technology
Gravity-fed and 3-product cyclone toproduce clean coal, middlings and reject atone time
Without desliming & without sizing rawcoal feed
Using single low density H.M. to realizehigh density separation
Large capacity: the largest cyclone3GDMC1500/1000 has a capacity of 550-650t/h without desliming
The gravity-fed 3-product cyclonetechnology has been used in over 400 plants inChina.
DEVELOPMENT OF TECHNOLOGIES AND EQUIPMENTGravity-fed 3-product H.M. cyclone
Features & Advantages:
Country Model and I.D.mm
# of product
Feedingmanner
Feed sizemm
Requirement for raw coal
Capacityt/h
Epmkg/L
Adjustment of2nd stage
separation density
Australia DSM1300 2 pressure 110~1.5 Deslimed 550 0.02~0.03 -
Britain LARCODEMS1350 2 Gravity-fed 120~1.5 Deslimed 450 0.02~0.03 -
Russia ΓTY900/630 3 Pressure 50~0.5 Deslimed 200 Epm1=0.03~0.04 Epm2=0.05~0.08
Shut-down to replace apex
China 3GDMC1500/1100A 3 Gravity-fed 110~0Non-deslimedNon-classified 606 Epm1=0.02~0.03
Epm2=0.04~0.06 On-line to adjust
Comparison of major technical specifications of domestic
and oversea large diameter heavy medium cyclones
Mixed, non-deslimed gravity-fed 3-product heavy medium cyclone technology
DEVELOPMENT OF TECHNOLOGIES AND EQUIPMENTGravity-fed 3-product H.M. cyclone
Performance of gravity-fed 3-product H. M. cyclone 2.1
Separation results using gravity-fed 3-product heavy medium cyclone
Plant Specifications of cyclone
Feed size mm
±0.1%
Ash,% Clean coal yield
%
Separation densitykg/L
Epkg/L
Raw Clean Coal Middlings Reject 1st stage 2nd stage 1st stage 2nd stage
Shanxi Wenfeng 1100/780 80-0 6.55 15.77 6.37 35.23 80.27 82.04 1.529 1.963 0.022 0.048
Anhui Linhuan 1200/850 95-0 14.30 36.03 9.79 37.79 85.17 61.79 1.540 1.860 0.020 0.040
Guizhou Laowuji 1300/920 80-0 38.26 34.22 9.54 24.47 76.99 56.65 1.430 1.688 0.025 0.045
Shanxi Jinyan 1400/1000 80-0 47.58 31.78 11.51 27.89 67.66 49.95 1.476 1.749 0.021 0.042
QipanjingInner
Mongolia1500/1100 100-0 47.06 46.92 10.19 25.39 71.37 25.31 1.415 1.670 0.022 0.024
Mixed, non-deslimed gravity-fed 3-product heavy medium cyclone technology
DEVELOPMENT OF TECHNOLOGIES AND EQUIPMENTGravity-fed 3-product H.M. cyclone
Coal Size Fraction > 0.5 mm (I) 0.02 – 0.025 (II) 0.025 – 0.05
Ep Value
The low separation size limit of gravity-fed 3-product H.M. cyclone and fine coal H.M. cyclone2.2
The plant test data on 3GDMC1500/1100 H.M. cyclone at Qipangjing :
Mixed, non-deslimed gravity-fed 3-product heavy medium cyclone technology
DEVELOPMENT OF TECHNOLOGIES AND EQUIPMENTGravity-fed 3-product H.M. cyclone
0.5~0.25 mm
Coal Size Fraction Epm Value Throughput Capacity
0.099kg/L 588~606 t/h,
The fine coal H.M. cyclone performance at the plant :
Coal Size Fraction Epm Value
0.1~0.074 mm 0.08 kg/L
There is no extra ultrafine
magnetite system needed
The Performance (Ep Values) of Spiral and TBS Versus Coal Particle Sizes
Reference: “Performance of the Teetered Bed Separator at the Murray Energy Century Preparation Plant”- Paper published in Coalprep 2009 Kentucky
DEVELOPMENT OF TECHNOLOGIES AND EQUIPMENT
Ep
Valu
es
Coal feed particle sizes (mm)
0.33
0.29
0.225
0.122
0.10 0.25 0.50
Coal slime slurry treatment technology
The “2+2” model of fine circuit process has been developed since 2006
The “2+2” model means:Fine clean coal circuit: 2-stage flotation and 2-stage dewateringFine tailings circuit: 2-stage thickening and 2-stage recovery
The purpose of “2+2” model slime circuit process:Recover all coal fines in plant and further reduce fine product H2O content
Realize closed water circuit in the plant with zero discharge of effluentSaving water with only 0.05-0.07 m3/t of water consumption in the plant
DEVELOPMENT OF TECHNOLOGIES AND EQUIPMENTFine Coal Circuit Process Technology
Fine Coal Slime Circuit Process Technology
To develop unique classified flotation process technology to handle low-
floatability and poor selectivity coal to reduce about 1% clean coal ash
content.
Addition of “coarse fine particles” into flotation froth to increase
capacity of de-watering equipments and reduce moisture content of
products;
Using two-stage de-watering, screen bowl centrifuge and filter press, to
reduce 5~10% of moisture content of clean fine coal.
Coal slime slurry treatment technology
DEVELOPMENT OF TECHNOLOGIES AND EQUIPMENTFine Coal Circuit Process Technology
Objectives:
Fine tailing process circuit flowsheet6.2
Objective:
① Maximizes the recovery of coarse fine reject, reduce its moisture contentand mix it with middlings;
② Realizes complete separation of solid and liquid for fine tailing slurry;
③ Addition of Ca++ and Mg++ ionic agglomerates as primary agentsand polypropylene type flocculant as a secondary agent to ensure completeclarifying of coal slurry and realize using clear water to wash coal.
Coal slime slurry treatment technology
DEVELOPMENT OF TECHNOLOGIES AND EQUIPMENTFine Coal Circuit Process Technology