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7172019 Artikel 3
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Fine coal dry cleaning using a vibrated gas-1047298uidized bed
Xuliang Yang Yuemin Zhao Zhenfu Luo Shulei Song Chenlong Duan Liang Dong
School of Chemical Engineering amp Technology China University of Mining and Technology 221008 Xuzhou China
a b s t r a c ta r t i c l e i n f o
Article history
Received 25 February 2012
Received in revised form 8 June 2012
Accepted 22 August 2012
Available online 19 September 2012
Keywords
Fine coal
Dry cleaning
Vibrated gas-1047298uidized bed
Segregation
Bubble-driven jigging
Fine coal (minus6 mm) cleaning in a dry way becomes more important with the extensive deployment of the mech-
anized mining and progressively serious water shortage especially in North-West China In this paper we
attempted to use the segregation in a vibrated gas-1047298uidized bed of dissimilar particles to provide a solution to
this problem The effects of several factors including the super1047297
cial air velocity bed height vibration intensityand1047298uidizing timeon the segregation performance wereexperimentally studiedThe bubble-driven jigging mech-
anismwas proposedto explain the separation processThe results showthat the probableerror E values of thesep-
aration of minus6+3 mm and minus3+1 mm size fraction of feed coal samples are 019 and 0175 respectively which
indicates that 1047297ne coal separation using a vibrated gas-1047298uidized bed can provide a simple and ef 1047297cient way for
coal cleaning in dry and cold regions in North-West China
copy 2012 Elsevier BV All rights reserved
1 Introduction
Dry cleaning of 1047297ne coal (minus6 mm) is an important issue in coal sec-
tor especially for China Large amounts of 1047297ne coal are produced during
coal mining as a result of the extensive deployment of the mechanizedmining technology and should be cleaned with the consideration of en-
ergy source conversation and environment protection In addition
Chinas coal reserves are mainly deposited in North-West China where
the arid geological environment and prolonged cold weather per year
present obstacles to the deployment of the coal wet cleaning technolo-
gies Thus it is urgent to develop a novel and ef 1047297cient dry cleaning tech-
nology for 1047297ne coal The cleaning technologies including air dense
medium 1047298uidized bed separator [12] air jigging [3] and FGX separator
[4] provide ef 1047297cient solutions to the dry cleaning of minus50+6 mm coal
Fan et al [56] studied magnetically stabilized 1047298uidized beds for separat-
ing1047297necoal(minus6+1 mm)Luoet al [7] introduced the vibrationenergy
to an air dense medium1047298uidized bed separator in order to provide a so-
lution to1047297necoal (minus6+ 1 mm) cleaningMacpherson et al[89] studied
the density-based separations of 1047297ne coal (minus8+1 mm) in the Re1047298ux
Classi1047297er with an airndashsand dense-medium and vibration Although
these three 1047297ne coal dry cleaning technologies give good separation
results they all encounter obstacles in the way of industrial applications
due to the problems of dense medium recovery product puri1047297cation
and low processing capacity Overall for 1047297ne coal (minus6 mm) there is no
effective dry cleaning technology that can work with great potential for
commercialization
Granular materials in a 1047298uidized bed can segregate due to differ-
ent material properties such as different densities andor sizes [10]
However stable 1047298uidization of coarse particles (+1 mm) that be-
longs to the type D material in the classi1047297cation by Geldart [11] is
very dif 1047297cult by ambient air solely The introduction of vibration en-
ergy to traditional gasndashsolid 1047298uidized beds can1047298uidize the coarsepar-
ticles effectively by enhancing the hydrodynamic interaction betweenair and particles and by eliminating the channeling of air 1047298ow within
the bed The segregation processes that occur simultaneously in vi-
brated gas-1047298uidized beds are solely and entirely by the bubbles [12]
Appropriate bubbling stability is responsible for a stable and effective
segregation behavior due to regular hydrodynamic interaction of the
two-phase 1047298ow [13] In this paper we focus on utilizing a vibrated
gas-1047298uidized bed to clean minus6+1 mm 1047297ne coal and studying the ef-
fects of different operational factors on the separation performance
2 Mechanism
In a vibrated gas-1047298uidized bed of coarse particles with different den-
sities the segregation is mainly caused by the bubbles When a bubble
rises through the granular bed a temporarily disturbed region having
considerable lower solid volume fraction than the surrounding bulk
phase is formed behind the bubble In this region particles with higher
density tend to sink preferentially over the lighter particles which
leads to local particle segregation The hindered settling velocity plays a
key role in this segregating process Brie1047298y high-density particles have
an opportunity to overtake low-density particles by falling rapidly
through the bubbles and also settling faster in the temporarily disturbed
regions Thebubblesimpose a periodic expansion and contraction on the
particle bed thereby causing separation mainly based on density rather
than size This process is analogousto theseparation technique of jigging
[13] and consequently the aforementioned separation mechanism can
be summarized as the bubble-driven jigging mechanism Like traditional
Fuel Processing Technology 106 (2013) 338ndash343
Corresponding author Tel +86 15162110730
E-mail address yangxuliang126com (X Yang)
0378-3820$ ndash see front matter copy 2012 Elsevier BV All rights reserved
httpdxdoiorg101016jfuproc201208019
Contents lists available at SciVerse ScienceDirect
Fuel Processing Technology
j o u r n a l h o m e p a g e w w w e l s e v i e r c o m l o c a t e f u p r o c
7172019 Artikel 3
httpslidepdfcomreaderfullartikel-3-568d98f1db858 26
jigging techniques good separation in a vibrated gas-1047298uidized bed also
requires enough bubble-driven jigging cycles In addition the achieve-
ment of optimal segregation is highly sensitive to several operational fac-
tors like the super1047297cial air velocity vibration intensity bed height and
1047298uidizing time for their signi1047297cant effects on the bubble behavior and
the 1047298uidization quality
3 Experimental
31 Coal particle properties
Fine coal is a multi-component granular system and has a consider-
able wide density distribution generally ranging from 12 to 24 gcm3
Thusnarrow size range of the feed is favorable to the particle segregation
basingon densitydifferencewhich will minimize the in1047298uence of particle
size difference on the hindered terminal settling velocity and reduce the
number of dissimilar particles having equal settling velocity For 1047297ne
coal separation using a vibrated gas-1047298uidized bed the ratio of the upper
limit size to the lower one is approximately no more than 31
In this paper two size fractions ieminus6+ 3 mm andminus3+1 mmcoal
were studied and their density distribution is given in Tables 1 and 2
respectively They both belong to high-ash coal which accounts for a con-
siderable large share of 1047297
ne coal in North-West China Both size fractionshave a large amount of high density materials of +18gcm3 of 3847
and 3768 respectively
32 Experimental apparatus
The schematic diagram of the experimental apparatus is shown in
Fig 1 The experimental apparatus of a vibrated gas-1047298uidized bed con-
sists of three main parts gas supply system vibration generating sys-
tem and 1047298uidized bed The 1047297ne coal particles are 1047298uidized in a vertical
cylinder with an inner diameter of 110 mm and a height of 400 mm
which is made from transparent plexiglass Ambient air after 1047297ltering
is dispersed by a sintered metal distributor and then enters the vessel
and 1047298uidizes the granular particles Air pressure is controlled over a
range from 01 to 025 MPa by a valve leading to the atmosphere thatregulates the pressure of the tank The vibrated bed deployed in this
studyis manufactured by China STI Co LTD and itsoperational param-
eters can be easily adjusted by a digital controller to generate vibration
motions with amplitude ranging from 0 mm to 10 mm and frequency
ranging from 1 Hz to 400 Hz OLYMPUS i-SPEED 3 high speed camera
system is used to study the particle motions within the bed in order
to reveal the separation process and verify the bubble-driven jigging
mechanism
33 Segregation evaluation
In this paper the segregation results are evaluated qualitatively and
quantitatively by the segregation pattern and the segregation degree
respectively The particle bed is 1047297
rstly 1047298
uidized for a certain time andthen the 1047298uidizing air is suddenly shut down The static particle bed is
divided into 1047297ve layers evenly in the axial direction and we take sam-
ples from each layer to test the ash content The segregation pattern is
obtained by plotting these ash content data with the dimensionless
bed height H lowast=H i H 0 as Y-axis where H i is the average bed height of
the ith sampling layer and H 0 is the total bed height of the static bed
A statistical indicator S is proposed to evaluate the segregation degree
quantitatively and the de1047297nition is shown in Eq (1)
S frac14
ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi Xn
ifrac141
Ai= A0minus1eth THORN2
nminus1
v uuut
eth1THORN
where Ai isthe ash content of coal ofthe ith sampling point A0 is the ini-
tial ash content of feed coal and n is the total sampling number It can
be clearly inferred from Eq (1) that when a granular system is perfectly
mixed Ai= A0 S =0 and a largervalueof S indicates better segregation
that is favorable for 1047297ne coal separation
4 Results and discussion
41 Effect of super 1047297cial air velocity on segregation
In a vibrated gas-1047298uidized bed the steady state of the granular sys-
tem is a result of the dynamic equilibrium between the competing pro-
cesses of mixing and segregation [14] The super1047297cial air velocity playsa critical role in achieving the optimal segregation results Besides the
dispersion uniformity of the 1047298uidizing air also has a signi1047297cant in1047298uence
on the bubble characteristics The optimal air velocity for segregation
highly depends on several factors including particle properties vibration
energy and bed height Thus a dimensionless super1047297cial air velocity
U lowast=(U minusU mb) U mb is introduced to study theeffect of super1047297cial air ve-
locity on segregation where U and U mb is the 1047298uidizing air velocity and
the minimum bubbling air velocity respectively
Fig 2 depicts the segregation results of the two types of feed coal
at different super1047297cial air velocities It can be seen that the two curves
both exhibit inverted V-shape and have single peak value that corre-
sponds to the best segregation degree For minus6+3 mm size feed coal
the U lowast value at this peak is equal to 02 while it is 015 forminus3+1 mm
Table 1
Results of the sink-1047298oat experiment of minus6+ 3 mm size fraction of coal
Density fraction
(gcm3)
Average density (gcm3) Weight fraction () Ash content ()
minus13 125 412 602
+13ndash14 135 2464 1031
+14ndash15 145 1694 1834
+15ndash16 155 606 2583
+16ndash17 165 292 3500
+17ndash18 175 685 4452
+18 22 3847 7597
Total 10000 4076
Table 2
Results of the sink-1047298oat experiment of minus3+ 1 mm size fraction of coal
Density fraction
(gcm3)
Average density (gcm3) Weight fraction () Ash content ()
minus13 125 602 581
+13ndash14 135 2352 1138
+14ndash15 145 1675 1768
+15ndash16 155 965 2424
+16ndash17 165 296 3681
+17ndash18 175 342 4424+18 22 3768 7652
Total 10000 3976
8
7
6
54
32
19
10 11
12
Fig 1 Schematic diagram of the experimental apparatus 1 Air 1047297lter 2 Roots blower
3 Tank 4 Pressure gauge 5 Valve 6 Rotameter 7 Vibrated bed 8 Air chamber 9
Air distributor 10 Vessel 11 High-speed camera 12 Image analysis system
339 X Yang et al Fuel Processing Technology 106 (2013) 338ndash 343
7172019 Artikel 3
httpslidepdfcomreaderfullartikel-3-568d98f1db858 36
size feed coal When the super1047297cial air velocity is larger than U mb the
excess air produces bubbles that divide the bed into particulate phase
and bubble phase Cibilaro and Rowe [12] pointed out that the mixing
and segregation processes in a gasndashsolid 1047298uidized bed mainly depend
on the bubbles Thus the bubble characteristics including bubble size
and bubble rise velocity signi1047297cantly determine the segregation
performance
Appropriate super1047297cial air velocity can generate the bubbles that
lead to the optimal segregation results When the bubble size is too
small there is no enough space for particle settling in the disturbed
region below the rising bubble When the bubble size is too big the
bubble rise velocity becomes too fast to provide enough time for par-
ticle settling in the disturbed region
42 Effect of vibration intensity on segregation
The verticalvibration may convenientlybe characterized by vibration
intensityΓ = Aω 2 g where A is the amplitude of the oscillationω =2π f is
the angular frequency f is the frequency of the oscillation and Γ is theratio of the maximum acceleration of the bed to the acceleration due to
gravity g The value range of A and the frequency f are 05ndash3 mm and
10ndash50 Hz respectively The minus6+3 mm and minus3+1 mm size friction
coal is separated at U lowast=015020 respectively under different vibration
intensity The segregation degree of the two types of feed coal is shown
in Fig 3 It can be seen that the two curves both exist with single peak
value which leads to the optimal segregation results In a vibrated
gas-1047298uidized bed of coarse particles the input vibration energy can
generate appropriate 1047298uidizing conditions for particle segregation by
eliminating the channeling of air 1047298ow within the bed and optimizing
the bubble characteristics due primarily to enhanced particle interaction
and particle piercing behavior However when the input vibration ener-
gy excesses the critical value the particle motion in the lower section of
the bed becomes severe enough to deteriorate thehindered settling pro-
cess which will lead to comparatively good mixing of the particle bed
43 Effect of bed height on segregation
Fig 4 depicts the segregation results of the two types of feed coal
with different initial bed height (H ) It can be seen that when bed
height is smaller than 70 mm the patterns of the two curves are
1047298at which indicates that the segregation degrees of the two types
of feed coal are both uniform But when the bed height is larger
than 70 mm the segregation performance of the two types of feed
coal both deteriorates dramatically This change is mainly derived
from the weaknesses of the vibration function to the 1047298uidizing condi-tion of the upper section of the particle bed when the bed height ex-
ceeds this critical value In addition bubble size at the upper section
of the bed with large bed height will become large enough to cause
large-scale particle circulations that deteriorate the segregation
process
44 Effect of 1047298uidizing time on segregation
According to the aforementioned separation mechanism the opti-
mal segregation requires enough bubble-driven jigging cycles in order
to provide enough time for particle segregation primarily depending
on the density differences Fig 5 demonstrates the segregation degree
of the two types of feed coal at different 1047298uidizing time We can see
clearly that the segregation degree of the two types of feed coal both in-creases with the 1047298uidizing time until it reaches to a critical value at
2 min and then the curves become 1047298at when the 1047298uidizing time ex-
ceeds 2 min These curves indicate that the two granular systems both
achieve a stable state of segregation after 2 min 1047298uidization and then
there is no improvement when enlarging the 1047298uidizing time
45 Veri 1047297cation of bubble-driven jigging mechanism
The aforementioned bubble-driven jigging mechanism canbe veri1047297ed
by theresults of image analysis of thepictures that are photographed by a
high-speed camera shown in Fig 6 Three particles labeled by 1 2 and 3
with particle size of minus3+1 mm represent clean coal gangue and mid-
dlings respectively These three particles are identi1047297ed visually by the dif-
ference in physical properties like shape color and luster using the image
50 60 70 80 90 100 110051
054
057
060
063
066
069
S
H (mm)
-3+1 mm
-6+3 mm
Fig 4 Segregation degree at different bed height
Fig 3 Segregation degree at different vibration intensity
005 010 015 020 025
02
03
04
05
06
07
-6+3 mm
-3+1 mm
S
U
Fig 2 Segregation degree at different super1047297cial gas velocities
340 X Yang et al Fuel Processing Technology 106 (2013) 338ndash 343
7172019 Artikel 3
httpslidepdfcomreaderfullartikel-3-568d98f1db858 46
magni1047297cation method and the identi1047297cation is concretely given in
Table 3 At 0 ms particles in the local region investigated are compact
and there are no visible particle motions When a bubble passes through
this region since 165 ms particles in this region become loose and differ-
ent in motion Particle 1 with lower density moves upwards along with
the bubble due to gas drag force while particle 2 and particle 3 settle
through the bubble quickly Since 615 ms in the disturbed region
below the bubble particle 2 settles faster than particle 3 And 1047297nally
after a bubble-driven jigging cycle the three investigated particles at
1065 ms are arranged in the axial direction with particle 1 (clean coal)
in the top particle 3 (middlings) in the middle and particle 2 (gangue)
in the bottom which is extremely consistent with the above description
of the bubble-driven jigging mechanism
46 Separation performance
Fig 7 depicts the segregation patterns corresponding to the opti-
mal segregation performance of the two types of feed coal and the
corresponding values of the aforementioned factors are listed inTable 4 Under this optimal conditions each feed coal is 1047297rstly sepa-
rated at a higher separation density to discharge thegangue andthen
the gangue-free coal is separated at a lower separation density to
produce the clean coal and the middlings The partition distribution of
three products of each feed coal is examined by carrying out the
sink-1047298oat experiments as given in Tables 5 and 6 respectively Based on
these data the partition curves of the two types of feed coal are plotted
in Fig 8 The separation results of the two types of feed coal are given in
Table 7 The probable error E values of minus6+3 mm and minus3+1 mm
size fraction of feed coal are 019ndash0225 and 0175ndash0195 respectively
With the comparison of the E value theminus3+ 1 mmfeed coalhasa better
separation ef 1047297ciency both at a high separation densityand a low one than
the minus6+3 mm feed coal This is because that minus3+1 mm feed coal is
easier to achieve uniform 1047298uidization with good bubbling behavior than
minus6+ 3 mm feed coal For each feed coal the E value at a high separation
density is smaller than that at a low one
5 Conclusion
In this study we focus on utilizing the segregation in a vibrated
gas-1047298uidized bed to provide a solution to the dif 1047297cult problem of 1047297ne
coal separation in a dry process which is greatly meaningful with re-
spect to the utilization of 1047297ne coal for energy resources in North-West
China In this process bubble-driven jigging cycles provide enough
space and time for the particles to segregate in the axial direction
depending on their hindered settling velocity differences The experi-
mental results show that the operational parameters including super1047297-
cial air velocity vibration intensity bed height and1047298uidizing time have
signi1047297cant in1047298uences on the segregation performance and the probablyerror E values of minus6+ 3 mm and minus3+1 mm size fraction of feed coal
are 019ndash0225 and 0175ndash0195 respectively According to the analysis
Fig 6 Particle segregation in a bubble-driven jigging cycle
Table 3
Physical properties of the clean coal middlings and gangue particles
Item Color Luster Shape
Clean coal Black Submetallicvitreous luster Round short-rod ellipse
Middlings Dark gray Bituminous luster Long-rod cuboid
Gangue Gray Dull luster Sheet strip
0 1 2 3 4035
040
045
050
055
060
065
070
075
S
T (min)
-6+3 mm
-3+1 mm
Fig 5 Segregation degree at different 1047298uidizing time
341 X Yang e t al Fuel Processing Technology 106 (2013) 338ndash 343
7172019 Artikel 3
httpslidepdfcomreaderfullartikel-3-568d98f1db858 56
of three product separation results the1047297ne coalseparation in a vibrated
gas-1047298uidized bed system is useful to and more effective for 1047297ne coal
cleaning in drought and cold regions
Acknowledgments
The research work involved in this paper received the 1047297nancial
support by the National Natural Science Foundation (No 51134022
51174203) the Key Project of Chinese National Programs for Fundamen-
tal Research and Development (973 program) (No 2012CB214904) the
National Natural Science Foundation of China for Innovative Research
Group (No 50921002) the Natural Science Foundation of Jiangsu Prov-
ince of China (No BK2010002) the Fundamental Research Funds for
the Central Universities (No 2010QNB11 2010ZDP01A06)
a
b
Fig 7 The optimal segregation patterns of the two types of feed coal
Table 4
Operational conditions leading to the optimal segregation performance of the two
types of the feed coal
Factors minus6+3 mm minus3+1 mm
U lowast 02 015
Γ 023 02
H (mm) 70 70
T (minutes) 2 2
Table 6
The sink-1047298oat results of the products of minus6+3 mm feed coal
Density
fraction
( g cm3)
Product weight fraction () Calculated feedstock () Partition
coef 1047297cient ()
Gangue Middlings Clean
coal
Total Reconcentration High
density
Low
density
minus13 015 054 321 390 375 391 1430
13ndash14 142 497 1825 2464 2322 576 2141
14ndash15 110 537 877 1524 1414 721 3797
15ndash16 072 317 326 716 644 1017 4929
16ndash17 057 174 121 352 295 1628 5915
17ndash18 250 390 144 784 534 3185 7304
+18 3338 385 048 3770 433 8852 8893
Total 3984 2354 3662 10000 6016
Table 5
The sink-1047298oat results of the products of minus3+1 mm feed coal
Density
fraction
( g cm3)
Product weight fraction () Calculated feedstock () Partition
coef 1047297cient ()
Gangue Middlings Clean
coal
Total Reconcentration High
density
Low
density
minus13 020 088 455 563 544 346 1626
13ndash14 087 455 1847 2389 2302 363 1978
14ndash15 098 568 977 1643 1545 597 3675
15ndash16 086 458 315 858 772 997 5927
16ndash17 042 153 069 263 222 1583 6895
17ndash18 212 121 041 374 162 5672 7492
+18 3477 386 046 3910 433 8893 8926
Total 40 21 2229 3750 10000 5979
12 14 16 18 20 22
0
20
40
60
80
100
P a r t i t i o n c o e f f i c i e n t ( )
Density (gcm3)
High-density separation
Low-density separation
-3+1 mm
12 14 16 18 20 22
0
20
40
60
80
100
-6+3 mm
High-density separation
Low-density separation
P a r t i t i o n c o e f f i c i e n t (
)
Density (gcm3)
a
b
Fig 8 Partition curves of the two types of feed coal
342 X Yang et al Fuel Processing Technology 106 (2013) 338ndash 343
7172019 Artikel 3
httpslidepdfcomreaderfullartikel-3-568d98f1db858 66
References
[1] Y Zhao L Tang Z Luo C Liang H Xing W Wu C Duan Experimental and numericalsimulation studies of the 1047298uidization characteristics of a separating gasndashsolid 1047298uidizedbed Fuel Processing Technology 91 (2) (2010) 1819ndash1825
[2] AK Sahu A Tripathy SK Biswal A Parida Stability study of an air dense medium1047298uidized bed separator for bene1047297ciation of high-ashIndian coal International Journalof Coal Preparation and Utilization 31 (3ndash4) (2011) 127ndash148
[3] CH Sampaio W Aliaga ET Pacheco E Petter H Wotruba Coal bene1047297ciation of Candiota mine by dry jigging Fuel Processing Technology 89 (2) (2008) 198ndash202
[4] B Zhang H Akbari F Yang MKMohanty J Hirschi Performance optimizationof the FGX dry separator for cleaning high-sulfur coal International Journal of CoalPreparation and Utilization 31 (3ndash4) (2011) 161ndash186
[5] M Fan Q Chen Y Zhao Z Luo Fine coal (6ndash1 mm) separation in magneticallystabilized 1047298uidized beds International Journal of Mineral Processing 63 (4)(2001) 225ndash232
[6] M Fan Q Chen Y Zhao Z Luo Y Guan Fundamentals of a magnetically stabilized1047298uidized bed for coal separation International Journal of Coal Preparation andUtilization 23 (1) (2003) 47ndash55
[7] Z Luo M Fan Y Zhao X Tao Q Chen Z Chen Density-dependent separation of dry 1047297ne coal in a vibrated 1047298uidized bed Powder Technology 187 (2) (2008)
119ndash
123[8] SA Macpherson SM Iveson KP Galvin Density based separations in the Re1047298uxClassi1047297er with an airumlCsand denseumlCmedium and vibration Minerals Engineering23 (2) (2010) 74ndash82
[9] SA Macpherson SM Iveson KP Galvin Density-based separation in a vibratedRe1047298ux Classi1047297erwithan airndashsand densendashmedium tracerstudies with simultaneousunder1047298owand over1047298ow removal Minerals Engineering 24 (10) (2011) 1046ndash1052
[10] PN Rowe AW Nienow Particle mixing and segregation in gas 1047298uidised beds Areview Powder Technology 15 (2) (1976) 141ndash147
[11] D Geldart Types of gas 1047298uidization Powder Technology 7 (5) (1973) 285ndash292[12] LG Gibilaro PN Rowe A model for a segregating gas 1047298uidised bed Chemical
Engineering Science 29 (6) (1974) 1403ndash1412[13] JF Davidson R Clift D Harrison Fluidization 2nd edn Academic Press Landon
1985[14] NS Naimer T Chiba AW Nienow Parameter estimation for a solids mixing
segregation model for gas 1047298uidised beds Chemical Engineering Science 37 (7)(1982) 1047ndash1057
Table 7
Separation results of 1047297ne coal in a vibrated gas-1047298uidized bed
Separation results minus6+3 mm minus3+1 mm
Feed ash content () 4076 3976
Low separation density ( g cm3) 155 152
High separation density ( g cm3) 189 177
Low density separation E 0225 0195
High density separation E 019 0175
Clean coal ash content () 1556 1442
Clean coal yield () 3662 3750Middlings ash content () 3247 3016
Middlings yield () 2354 2229
Gangue ash content () 7007 7102
Gangue yield () 3984 4021
343 X Yang et al Fuel Processing Technology 106 (2013) 338ndash 343
7172019 Artikel 3
httpslidepdfcomreaderfullartikel-3-568d98f1db858 26
jigging techniques good separation in a vibrated gas-1047298uidized bed also
requires enough bubble-driven jigging cycles In addition the achieve-
ment of optimal segregation is highly sensitive to several operational fac-
tors like the super1047297cial air velocity vibration intensity bed height and
1047298uidizing time for their signi1047297cant effects on the bubble behavior and
the 1047298uidization quality
3 Experimental
31 Coal particle properties
Fine coal is a multi-component granular system and has a consider-
able wide density distribution generally ranging from 12 to 24 gcm3
Thusnarrow size range of the feed is favorable to the particle segregation
basingon densitydifferencewhich will minimize the in1047298uence of particle
size difference on the hindered terminal settling velocity and reduce the
number of dissimilar particles having equal settling velocity For 1047297ne
coal separation using a vibrated gas-1047298uidized bed the ratio of the upper
limit size to the lower one is approximately no more than 31
In this paper two size fractions ieminus6+ 3 mm andminus3+1 mmcoal
were studied and their density distribution is given in Tables 1 and 2
respectively They both belong to high-ash coal which accounts for a con-
siderable large share of 1047297
ne coal in North-West China Both size fractionshave a large amount of high density materials of +18gcm3 of 3847
and 3768 respectively
32 Experimental apparatus
The schematic diagram of the experimental apparatus is shown in
Fig 1 The experimental apparatus of a vibrated gas-1047298uidized bed con-
sists of three main parts gas supply system vibration generating sys-
tem and 1047298uidized bed The 1047297ne coal particles are 1047298uidized in a vertical
cylinder with an inner diameter of 110 mm and a height of 400 mm
which is made from transparent plexiglass Ambient air after 1047297ltering
is dispersed by a sintered metal distributor and then enters the vessel
and 1047298uidizes the granular particles Air pressure is controlled over a
range from 01 to 025 MPa by a valve leading to the atmosphere thatregulates the pressure of the tank The vibrated bed deployed in this
studyis manufactured by China STI Co LTD and itsoperational param-
eters can be easily adjusted by a digital controller to generate vibration
motions with amplitude ranging from 0 mm to 10 mm and frequency
ranging from 1 Hz to 400 Hz OLYMPUS i-SPEED 3 high speed camera
system is used to study the particle motions within the bed in order
to reveal the separation process and verify the bubble-driven jigging
mechanism
33 Segregation evaluation
In this paper the segregation results are evaluated qualitatively and
quantitatively by the segregation pattern and the segregation degree
respectively The particle bed is 1047297
rstly 1047298
uidized for a certain time andthen the 1047298uidizing air is suddenly shut down The static particle bed is
divided into 1047297ve layers evenly in the axial direction and we take sam-
ples from each layer to test the ash content The segregation pattern is
obtained by plotting these ash content data with the dimensionless
bed height H lowast=H i H 0 as Y-axis where H i is the average bed height of
the ith sampling layer and H 0 is the total bed height of the static bed
A statistical indicator S is proposed to evaluate the segregation degree
quantitatively and the de1047297nition is shown in Eq (1)
S frac14
ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi Xn
ifrac141
Ai= A0minus1eth THORN2
nminus1
v uuut
eth1THORN
where Ai isthe ash content of coal ofthe ith sampling point A0 is the ini-
tial ash content of feed coal and n is the total sampling number It can
be clearly inferred from Eq (1) that when a granular system is perfectly
mixed Ai= A0 S =0 and a largervalueof S indicates better segregation
that is favorable for 1047297ne coal separation
4 Results and discussion
41 Effect of super 1047297cial air velocity on segregation
In a vibrated gas-1047298uidized bed the steady state of the granular sys-
tem is a result of the dynamic equilibrium between the competing pro-
cesses of mixing and segregation [14] The super1047297cial air velocity playsa critical role in achieving the optimal segregation results Besides the
dispersion uniformity of the 1047298uidizing air also has a signi1047297cant in1047298uence
on the bubble characteristics The optimal air velocity for segregation
highly depends on several factors including particle properties vibration
energy and bed height Thus a dimensionless super1047297cial air velocity
U lowast=(U minusU mb) U mb is introduced to study theeffect of super1047297cial air ve-
locity on segregation where U and U mb is the 1047298uidizing air velocity and
the minimum bubbling air velocity respectively
Fig 2 depicts the segregation results of the two types of feed coal
at different super1047297cial air velocities It can be seen that the two curves
both exhibit inverted V-shape and have single peak value that corre-
sponds to the best segregation degree For minus6+3 mm size feed coal
the U lowast value at this peak is equal to 02 while it is 015 forminus3+1 mm
Table 1
Results of the sink-1047298oat experiment of minus6+ 3 mm size fraction of coal
Density fraction
(gcm3)
Average density (gcm3) Weight fraction () Ash content ()
minus13 125 412 602
+13ndash14 135 2464 1031
+14ndash15 145 1694 1834
+15ndash16 155 606 2583
+16ndash17 165 292 3500
+17ndash18 175 685 4452
+18 22 3847 7597
Total 10000 4076
Table 2
Results of the sink-1047298oat experiment of minus3+ 1 mm size fraction of coal
Density fraction
(gcm3)
Average density (gcm3) Weight fraction () Ash content ()
minus13 125 602 581
+13ndash14 135 2352 1138
+14ndash15 145 1675 1768
+15ndash16 155 965 2424
+16ndash17 165 296 3681
+17ndash18 175 342 4424+18 22 3768 7652
Total 10000 3976
8
7
6
54
32
19
10 11
12
Fig 1 Schematic diagram of the experimental apparatus 1 Air 1047297lter 2 Roots blower
3 Tank 4 Pressure gauge 5 Valve 6 Rotameter 7 Vibrated bed 8 Air chamber 9
Air distributor 10 Vessel 11 High-speed camera 12 Image analysis system
339 X Yang et al Fuel Processing Technology 106 (2013) 338ndash 343
7172019 Artikel 3
httpslidepdfcomreaderfullartikel-3-568d98f1db858 36
size feed coal When the super1047297cial air velocity is larger than U mb the
excess air produces bubbles that divide the bed into particulate phase
and bubble phase Cibilaro and Rowe [12] pointed out that the mixing
and segregation processes in a gasndashsolid 1047298uidized bed mainly depend
on the bubbles Thus the bubble characteristics including bubble size
and bubble rise velocity signi1047297cantly determine the segregation
performance
Appropriate super1047297cial air velocity can generate the bubbles that
lead to the optimal segregation results When the bubble size is too
small there is no enough space for particle settling in the disturbed
region below the rising bubble When the bubble size is too big the
bubble rise velocity becomes too fast to provide enough time for par-
ticle settling in the disturbed region
42 Effect of vibration intensity on segregation
The verticalvibration may convenientlybe characterized by vibration
intensityΓ = Aω 2 g where A is the amplitude of the oscillationω =2π f is
the angular frequency f is the frequency of the oscillation and Γ is theratio of the maximum acceleration of the bed to the acceleration due to
gravity g The value range of A and the frequency f are 05ndash3 mm and
10ndash50 Hz respectively The minus6+3 mm and minus3+1 mm size friction
coal is separated at U lowast=015020 respectively under different vibration
intensity The segregation degree of the two types of feed coal is shown
in Fig 3 It can be seen that the two curves both exist with single peak
value which leads to the optimal segregation results In a vibrated
gas-1047298uidized bed of coarse particles the input vibration energy can
generate appropriate 1047298uidizing conditions for particle segregation by
eliminating the channeling of air 1047298ow within the bed and optimizing
the bubble characteristics due primarily to enhanced particle interaction
and particle piercing behavior However when the input vibration ener-
gy excesses the critical value the particle motion in the lower section of
the bed becomes severe enough to deteriorate thehindered settling pro-
cess which will lead to comparatively good mixing of the particle bed
43 Effect of bed height on segregation
Fig 4 depicts the segregation results of the two types of feed coal
with different initial bed height (H ) It can be seen that when bed
height is smaller than 70 mm the patterns of the two curves are
1047298at which indicates that the segregation degrees of the two types
of feed coal are both uniform But when the bed height is larger
than 70 mm the segregation performance of the two types of feed
coal both deteriorates dramatically This change is mainly derived
from the weaknesses of the vibration function to the 1047298uidizing condi-tion of the upper section of the particle bed when the bed height ex-
ceeds this critical value In addition bubble size at the upper section
of the bed with large bed height will become large enough to cause
large-scale particle circulations that deteriorate the segregation
process
44 Effect of 1047298uidizing time on segregation
According to the aforementioned separation mechanism the opti-
mal segregation requires enough bubble-driven jigging cycles in order
to provide enough time for particle segregation primarily depending
on the density differences Fig 5 demonstrates the segregation degree
of the two types of feed coal at different 1047298uidizing time We can see
clearly that the segregation degree of the two types of feed coal both in-creases with the 1047298uidizing time until it reaches to a critical value at
2 min and then the curves become 1047298at when the 1047298uidizing time ex-
ceeds 2 min These curves indicate that the two granular systems both
achieve a stable state of segregation after 2 min 1047298uidization and then
there is no improvement when enlarging the 1047298uidizing time
45 Veri 1047297cation of bubble-driven jigging mechanism
The aforementioned bubble-driven jigging mechanism canbe veri1047297ed
by theresults of image analysis of thepictures that are photographed by a
high-speed camera shown in Fig 6 Three particles labeled by 1 2 and 3
with particle size of minus3+1 mm represent clean coal gangue and mid-
dlings respectively These three particles are identi1047297ed visually by the dif-
ference in physical properties like shape color and luster using the image
50 60 70 80 90 100 110051
054
057
060
063
066
069
S
H (mm)
-3+1 mm
-6+3 mm
Fig 4 Segregation degree at different bed height
Fig 3 Segregation degree at different vibration intensity
005 010 015 020 025
02
03
04
05
06
07
-6+3 mm
-3+1 mm
S
U
Fig 2 Segregation degree at different super1047297cial gas velocities
340 X Yang et al Fuel Processing Technology 106 (2013) 338ndash 343
7172019 Artikel 3
httpslidepdfcomreaderfullartikel-3-568d98f1db858 46
magni1047297cation method and the identi1047297cation is concretely given in
Table 3 At 0 ms particles in the local region investigated are compact
and there are no visible particle motions When a bubble passes through
this region since 165 ms particles in this region become loose and differ-
ent in motion Particle 1 with lower density moves upwards along with
the bubble due to gas drag force while particle 2 and particle 3 settle
through the bubble quickly Since 615 ms in the disturbed region
below the bubble particle 2 settles faster than particle 3 And 1047297nally
after a bubble-driven jigging cycle the three investigated particles at
1065 ms are arranged in the axial direction with particle 1 (clean coal)
in the top particle 3 (middlings) in the middle and particle 2 (gangue)
in the bottom which is extremely consistent with the above description
of the bubble-driven jigging mechanism
46 Separation performance
Fig 7 depicts the segregation patterns corresponding to the opti-
mal segregation performance of the two types of feed coal and the
corresponding values of the aforementioned factors are listed inTable 4 Under this optimal conditions each feed coal is 1047297rstly sepa-
rated at a higher separation density to discharge thegangue andthen
the gangue-free coal is separated at a lower separation density to
produce the clean coal and the middlings The partition distribution of
three products of each feed coal is examined by carrying out the
sink-1047298oat experiments as given in Tables 5 and 6 respectively Based on
these data the partition curves of the two types of feed coal are plotted
in Fig 8 The separation results of the two types of feed coal are given in
Table 7 The probable error E values of minus6+3 mm and minus3+1 mm
size fraction of feed coal are 019ndash0225 and 0175ndash0195 respectively
With the comparison of the E value theminus3+ 1 mmfeed coalhasa better
separation ef 1047297ciency both at a high separation densityand a low one than
the minus6+3 mm feed coal This is because that minus3+1 mm feed coal is
easier to achieve uniform 1047298uidization with good bubbling behavior than
minus6+ 3 mm feed coal For each feed coal the E value at a high separation
density is smaller than that at a low one
5 Conclusion
In this study we focus on utilizing the segregation in a vibrated
gas-1047298uidized bed to provide a solution to the dif 1047297cult problem of 1047297ne
coal separation in a dry process which is greatly meaningful with re-
spect to the utilization of 1047297ne coal for energy resources in North-West
China In this process bubble-driven jigging cycles provide enough
space and time for the particles to segregate in the axial direction
depending on their hindered settling velocity differences The experi-
mental results show that the operational parameters including super1047297-
cial air velocity vibration intensity bed height and1047298uidizing time have
signi1047297cant in1047298uences on the segregation performance and the probablyerror E values of minus6+ 3 mm and minus3+1 mm size fraction of feed coal
are 019ndash0225 and 0175ndash0195 respectively According to the analysis
Fig 6 Particle segregation in a bubble-driven jigging cycle
Table 3
Physical properties of the clean coal middlings and gangue particles
Item Color Luster Shape
Clean coal Black Submetallicvitreous luster Round short-rod ellipse
Middlings Dark gray Bituminous luster Long-rod cuboid
Gangue Gray Dull luster Sheet strip
0 1 2 3 4035
040
045
050
055
060
065
070
075
S
T (min)
-6+3 mm
-3+1 mm
Fig 5 Segregation degree at different 1047298uidizing time
341 X Yang e t al Fuel Processing Technology 106 (2013) 338ndash 343
7172019 Artikel 3
httpslidepdfcomreaderfullartikel-3-568d98f1db858 56
of three product separation results the1047297ne coalseparation in a vibrated
gas-1047298uidized bed system is useful to and more effective for 1047297ne coal
cleaning in drought and cold regions
Acknowledgments
The research work involved in this paper received the 1047297nancial
support by the National Natural Science Foundation (No 51134022
51174203) the Key Project of Chinese National Programs for Fundamen-
tal Research and Development (973 program) (No 2012CB214904) the
National Natural Science Foundation of China for Innovative Research
Group (No 50921002) the Natural Science Foundation of Jiangsu Prov-
ince of China (No BK2010002) the Fundamental Research Funds for
the Central Universities (No 2010QNB11 2010ZDP01A06)
a
b
Fig 7 The optimal segregation patterns of the two types of feed coal
Table 4
Operational conditions leading to the optimal segregation performance of the two
types of the feed coal
Factors minus6+3 mm minus3+1 mm
U lowast 02 015
Γ 023 02
H (mm) 70 70
T (minutes) 2 2
Table 6
The sink-1047298oat results of the products of minus6+3 mm feed coal
Density
fraction
( g cm3)
Product weight fraction () Calculated feedstock () Partition
coef 1047297cient ()
Gangue Middlings Clean
coal
Total Reconcentration High
density
Low
density
minus13 015 054 321 390 375 391 1430
13ndash14 142 497 1825 2464 2322 576 2141
14ndash15 110 537 877 1524 1414 721 3797
15ndash16 072 317 326 716 644 1017 4929
16ndash17 057 174 121 352 295 1628 5915
17ndash18 250 390 144 784 534 3185 7304
+18 3338 385 048 3770 433 8852 8893
Total 3984 2354 3662 10000 6016
Table 5
The sink-1047298oat results of the products of minus3+1 mm feed coal
Density
fraction
( g cm3)
Product weight fraction () Calculated feedstock () Partition
coef 1047297cient ()
Gangue Middlings Clean
coal
Total Reconcentration High
density
Low
density
minus13 020 088 455 563 544 346 1626
13ndash14 087 455 1847 2389 2302 363 1978
14ndash15 098 568 977 1643 1545 597 3675
15ndash16 086 458 315 858 772 997 5927
16ndash17 042 153 069 263 222 1583 6895
17ndash18 212 121 041 374 162 5672 7492
+18 3477 386 046 3910 433 8893 8926
Total 40 21 2229 3750 10000 5979
12 14 16 18 20 22
0
20
40
60
80
100
P a r t i t i o n c o e f f i c i e n t ( )
Density (gcm3)
High-density separation
Low-density separation
-3+1 mm
12 14 16 18 20 22
0
20
40
60
80
100
-6+3 mm
High-density separation
Low-density separation
P a r t i t i o n c o e f f i c i e n t (
)
Density (gcm3)
a
b
Fig 8 Partition curves of the two types of feed coal
342 X Yang et al Fuel Processing Technology 106 (2013) 338ndash 343
7172019 Artikel 3
httpslidepdfcomreaderfullartikel-3-568d98f1db858 66
References
[1] Y Zhao L Tang Z Luo C Liang H Xing W Wu C Duan Experimental and numericalsimulation studies of the 1047298uidization characteristics of a separating gasndashsolid 1047298uidizedbed Fuel Processing Technology 91 (2) (2010) 1819ndash1825
[2] AK Sahu A Tripathy SK Biswal A Parida Stability study of an air dense medium1047298uidized bed separator for bene1047297ciation of high-ashIndian coal International Journalof Coal Preparation and Utilization 31 (3ndash4) (2011) 127ndash148
[3] CH Sampaio W Aliaga ET Pacheco E Petter H Wotruba Coal bene1047297ciation of Candiota mine by dry jigging Fuel Processing Technology 89 (2) (2008) 198ndash202
[4] B Zhang H Akbari F Yang MKMohanty J Hirschi Performance optimizationof the FGX dry separator for cleaning high-sulfur coal International Journal of CoalPreparation and Utilization 31 (3ndash4) (2011) 161ndash186
[5] M Fan Q Chen Y Zhao Z Luo Fine coal (6ndash1 mm) separation in magneticallystabilized 1047298uidized beds International Journal of Mineral Processing 63 (4)(2001) 225ndash232
[6] M Fan Q Chen Y Zhao Z Luo Y Guan Fundamentals of a magnetically stabilized1047298uidized bed for coal separation International Journal of Coal Preparation andUtilization 23 (1) (2003) 47ndash55
[7] Z Luo M Fan Y Zhao X Tao Q Chen Z Chen Density-dependent separation of dry 1047297ne coal in a vibrated 1047298uidized bed Powder Technology 187 (2) (2008)
119ndash
123[8] SA Macpherson SM Iveson KP Galvin Density based separations in the Re1047298uxClassi1047297er with an airumlCsand denseumlCmedium and vibration Minerals Engineering23 (2) (2010) 74ndash82
[9] SA Macpherson SM Iveson KP Galvin Density-based separation in a vibratedRe1047298ux Classi1047297erwithan airndashsand densendashmedium tracerstudies with simultaneousunder1047298owand over1047298ow removal Minerals Engineering 24 (10) (2011) 1046ndash1052
[10] PN Rowe AW Nienow Particle mixing and segregation in gas 1047298uidised beds Areview Powder Technology 15 (2) (1976) 141ndash147
[11] D Geldart Types of gas 1047298uidization Powder Technology 7 (5) (1973) 285ndash292[12] LG Gibilaro PN Rowe A model for a segregating gas 1047298uidised bed Chemical
Engineering Science 29 (6) (1974) 1403ndash1412[13] JF Davidson R Clift D Harrison Fluidization 2nd edn Academic Press Landon
1985[14] NS Naimer T Chiba AW Nienow Parameter estimation for a solids mixing
segregation model for gas 1047298uidised beds Chemical Engineering Science 37 (7)(1982) 1047ndash1057
Table 7
Separation results of 1047297ne coal in a vibrated gas-1047298uidized bed
Separation results minus6+3 mm minus3+1 mm
Feed ash content () 4076 3976
Low separation density ( g cm3) 155 152
High separation density ( g cm3) 189 177
Low density separation E 0225 0195
High density separation E 019 0175
Clean coal ash content () 1556 1442
Clean coal yield () 3662 3750Middlings ash content () 3247 3016
Middlings yield () 2354 2229
Gangue ash content () 7007 7102
Gangue yield () 3984 4021
343 X Yang et al Fuel Processing Technology 106 (2013) 338ndash 343
7172019 Artikel 3
httpslidepdfcomreaderfullartikel-3-568d98f1db858 36
size feed coal When the super1047297cial air velocity is larger than U mb the
excess air produces bubbles that divide the bed into particulate phase
and bubble phase Cibilaro and Rowe [12] pointed out that the mixing
and segregation processes in a gasndashsolid 1047298uidized bed mainly depend
on the bubbles Thus the bubble characteristics including bubble size
and bubble rise velocity signi1047297cantly determine the segregation
performance
Appropriate super1047297cial air velocity can generate the bubbles that
lead to the optimal segregation results When the bubble size is too
small there is no enough space for particle settling in the disturbed
region below the rising bubble When the bubble size is too big the
bubble rise velocity becomes too fast to provide enough time for par-
ticle settling in the disturbed region
42 Effect of vibration intensity on segregation
The verticalvibration may convenientlybe characterized by vibration
intensityΓ = Aω 2 g where A is the amplitude of the oscillationω =2π f is
the angular frequency f is the frequency of the oscillation and Γ is theratio of the maximum acceleration of the bed to the acceleration due to
gravity g The value range of A and the frequency f are 05ndash3 mm and
10ndash50 Hz respectively The minus6+3 mm and minus3+1 mm size friction
coal is separated at U lowast=015020 respectively under different vibration
intensity The segregation degree of the two types of feed coal is shown
in Fig 3 It can be seen that the two curves both exist with single peak
value which leads to the optimal segregation results In a vibrated
gas-1047298uidized bed of coarse particles the input vibration energy can
generate appropriate 1047298uidizing conditions for particle segregation by
eliminating the channeling of air 1047298ow within the bed and optimizing
the bubble characteristics due primarily to enhanced particle interaction
and particle piercing behavior However when the input vibration ener-
gy excesses the critical value the particle motion in the lower section of
the bed becomes severe enough to deteriorate thehindered settling pro-
cess which will lead to comparatively good mixing of the particle bed
43 Effect of bed height on segregation
Fig 4 depicts the segregation results of the two types of feed coal
with different initial bed height (H ) It can be seen that when bed
height is smaller than 70 mm the patterns of the two curves are
1047298at which indicates that the segregation degrees of the two types
of feed coal are both uniform But when the bed height is larger
than 70 mm the segregation performance of the two types of feed
coal both deteriorates dramatically This change is mainly derived
from the weaknesses of the vibration function to the 1047298uidizing condi-tion of the upper section of the particle bed when the bed height ex-
ceeds this critical value In addition bubble size at the upper section
of the bed with large bed height will become large enough to cause
large-scale particle circulations that deteriorate the segregation
process
44 Effect of 1047298uidizing time on segregation
According to the aforementioned separation mechanism the opti-
mal segregation requires enough bubble-driven jigging cycles in order
to provide enough time for particle segregation primarily depending
on the density differences Fig 5 demonstrates the segregation degree
of the two types of feed coal at different 1047298uidizing time We can see
clearly that the segregation degree of the two types of feed coal both in-creases with the 1047298uidizing time until it reaches to a critical value at
2 min and then the curves become 1047298at when the 1047298uidizing time ex-
ceeds 2 min These curves indicate that the two granular systems both
achieve a stable state of segregation after 2 min 1047298uidization and then
there is no improvement when enlarging the 1047298uidizing time
45 Veri 1047297cation of bubble-driven jigging mechanism
The aforementioned bubble-driven jigging mechanism canbe veri1047297ed
by theresults of image analysis of thepictures that are photographed by a
high-speed camera shown in Fig 6 Three particles labeled by 1 2 and 3
with particle size of minus3+1 mm represent clean coal gangue and mid-
dlings respectively These three particles are identi1047297ed visually by the dif-
ference in physical properties like shape color and luster using the image
50 60 70 80 90 100 110051
054
057
060
063
066
069
S
H (mm)
-3+1 mm
-6+3 mm
Fig 4 Segregation degree at different bed height
Fig 3 Segregation degree at different vibration intensity
005 010 015 020 025
02
03
04
05
06
07
-6+3 mm
-3+1 mm
S
U
Fig 2 Segregation degree at different super1047297cial gas velocities
340 X Yang et al Fuel Processing Technology 106 (2013) 338ndash 343
7172019 Artikel 3
httpslidepdfcomreaderfullartikel-3-568d98f1db858 46
magni1047297cation method and the identi1047297cation is concretely given in
Table 3 At 0 ms particles in the local region investigated are compact
and there are no visible particle motions When a bubble passes through
this region since 165 ms particles in this region become loose and differ-
ent in motion Particle 1 with lower density moves upwards along with
the bubble due to gas drag force while particle 2 and particle 3 settle
through the bubble quickly Since 615 ms in the disturbed region
below the bubble particle 2 settles faster than particle 3 And 1047297nally
after a bubble-driven jigging cycle the three investigated particles at
1065 ms are arranged in the axial direction with particle 1 (clean coal)
in the top particle 3 (middlings) in the middle and particle 2 (gangue)
in the bottom which is extremely consistent with the above description
of the bubble-driven jigging mechanism
46 Separation performance
Fig 7 depicts the segregation patterns corresponding to the opti-
mal segregation performance of the two types of feed coal and the
corresponding values of the aforementioned factors are listed inTable 4 Under this optimal conditions each feed coal is 1047297rstly sepa-
rated at a higher separation density to discharge thegangue andthen
the gangue-free coal is separated at a lower separation density to
produce the clean coal and the middlings The partition distribution of
three products of each feed coal is examined by carrying out the
sink-1047298oat experiments as given in Tables 5 and 6 respectively Based on
these data the partition curves of the two types of feed coal are plotted
in Fig 8 The separation results of the two types of feed coal are given in
Table 7 The probable error E values of minus6+3 mm and minus3+1 mm
size fraction of feed coal are 019ndash0225 and 0175ndash0195 respectively
With the comparison of the E value theminus3+ 1 mmfeed coalhasa better
separation ef 1047297ciency both at a high separation densityand a low one than
the minus6+3 mm feed coal This is because that minus3+1 mm feed coal is
easier to achieve uniform 1047298uidization with good bubbling behavior than
minus6+ 3 mm feed coal For each feed coal the E value at a high separation
density is smaller than that at a low one
5 Conclusion
In this study we focus on utilizing the segregation in a vibrated
gas-1047298uidized bed to provide a solution to the dif 1047297cult problem of 1047297ne
coal separation in a dry process which is greatly meaningful with re-
spect to the utilization of 1047297ne coal for energy resources in North-West
China In this process bubble-driven jigging cycles provide enough
space and time for the particles to segregate in the axial direction
depending on their hindered settling velocity differences The experi-
mental results show that the operational parameters including super1047297-
cial air velocity vibration intensity bed height and1047298uidizing time have
signi1047297cant in1047298uences on the segregation performance and the probablyerror E values of minus6+ 3 mm and minus3+1 mm size fraction of feed coal
are 019ndash0225 and 0175ndash0195 respectively According to the analysis
Fig 6 Particle segregation in a bubble-driven jigging cycle
Table 3
Physical properties of the clean coal middlings and gangue particles
Item Color Luster Shape
Clean coal Black Submetallicvitreous luster Round short-rod ellipse
Middlings Dark gray Bituminous luster Long-rod cuboid
Gangue Gray Dull luster Sheet strip
0 1 2 3 4035
040
045
050
055
060
065
070
075
S
T (min)
-6+3 mm
-3+1 mm
Fig 5 Segregation degree at different 1047298uidizing time
341 X Yang e t al Fuel Processing Technology 106 (2013) 338ndash 343
7172019 Artikel 3
httpslidepdfcomreaderfullartikel-3-568d98f1db858 56
of three product separation results the1047297ne coalseparation in a vibrated
gas-1047298uidized bed system is useful to and more effective for 1047297ne coal
cleaning in drought and cold regions
Acknowledgments
The research work involved in this paper received the 1047297nancial
support by the National Natural Science Foundation (No 51134022
51174203) the Key Project of Chinese National Programs for Fundamen-
tal Research and Development (973 program) (No 2012CB214904) the
National Natural Science Foundation of China for Innovative Research
Group (No 50921002) the Natural Science Foundation of Jiangsu Prov-
ince of China (No BK2010002) the Fundamental Research Funds for
the Central Universities (No 2010QNB11 2010ZDP01A06)
a
b
Fig 7 The optimal segregation patterns of the two types of feed coal
Table 4
Operational conditions leading to the optimal segregation performance of the two
types of the feed coal
Factors minus6+3 mm minus3+1 mm
U lowast 02 015
Γ 023 02
H (mm) 70 70
T (minutes) 2 2
Table 6
The sink-1047298oat results of the products of minus6+3 mm feed coal
Density
fraction
( g cm3)
Product weight fraction () Calculated feedstock () Partition
coef 1047297cient ()
Gangue Middlings Clean
coal
Total Reconcentration High
density
Low
density
minus13 015 054 321 390 375 391 1430
13ndash14 142 497 1825 2464 2322 576 2141
14ndash15 110 537 877 1524 1414 721 3797
15ndash16 072 317 326 716 644 1017 4929
16ndash17 057 174 121 352 295 1628 5915
17ndash18 250 390 144 784 534 3185 7304
+18 3338 385 048 3770 433 8852 8893
Total 3984 2354 3662 10000 6016
Table 5
The sink-1047298oat results of the products of minus3+1 mm feed coal
Density
fraction
( g cm3)
Product weight fraction () Calculated feedstock () Partition
coef 1047297cient ()
Gangue Middlings Clean
coal
Total Reconcentration High
density
Low
density
minus13 020 088 455 563 544 346 1626
13ndash14 087 455 1847 2389 2302 363 1978
14ndash15 098 568 977 1643 1545 597 3675
15ndash16 086 458 315 858 772 997 5927
16ndash17 042 153 069 263 222 1583 6895
17ndash18 212 121 041 374 162 5672 7492
+18 3477 386 046 3910 433 8893 8926
Total 40 21 2229 3750 10000 5979
12 14 16 18 20 22
0
20
40
60
80
100
P a r t i t i o n c o e f f i c i e n t ( )
Density (gcm3)
High-density separation
Low-density separation
-3+1 mm
12 14 16 18 20 22
0
20
40
60
80
100
-6+3 mm
High-density separation
Low-density separation
P a r t i t i o n c o e f f i c i e n t (
)
Density (gcm3)
a
b
Fig 8 Partition curves of the two types of feed coal
342 X Yang et al Fuel Processing Technology 106 (2013) 338ndash 343
7172019 Artikel 3
httpslidepdfcomreaderfullartikel-3-568d98f1db858 66
References
[1] Y Zhao L Tang Z Luo C Liang H Xing W Wu C Duan Experimental and numericalsimulation studies of the 1047298uidization characteristics of a separating gasndashsolid 1047298uidizedbed Fuel Processing Technology 91 (2) (2010) 1819ndash1825
[2] AK Sahu A Tripathy SK Biswal A Parida Stability study of an air dense medium1047298uidized bed separator for bene1047297ciation of high-ashIndian coal International Journalof Coal Preparation and Utilization 31 (3ndash4) (2011) 127ndash148
[3] CH Sampaio W Aliaga ET Pacheco E Petter H Wotruba Coal bene1047297ciation of Candiota mine by dry jigging Fuel Processing Technology 89 (2) (2008) 198ndash202
[4] B Zhang H Akbari F Yang MKMohanty J Hirschi Performance optimizationof the FGX dry separator for cleaning high-sulfur coal International Journal of CoalPreparation and Utilization 31 (3ndash4) (2011) 161ndash186
[5] M Fan Q Chen Y Zhao Z Luo Fine coal (6ndash1 mm) separation in magneticallystabilized 1047298uidized beds International Journal of Mineral Processing 63 (4)(2001) 225ndash232
[6] M Fan Q Chen Y Zhao Z Luo Y Guan Fundamentals of a magnetically stabilized1047298uidized bed for coal separation International Journal of Coal Preparation andUtilization 23 (1) (2003) 47ndash55
[7] Z Luo M Fan Y Zhao X Tao Q Chen Z Chen Density-dependent separation of dry 1047297ne coal in a vibrated 1047298uidized bed Powder Technology 187 (2) (2008)
119ndash
123[8] SA Macpherson SM Iveson KP Galvin Density based separations in the Re1047298uxClassi1047297er with an airumlCsand denseumlCmedium and vibration Minerals Engineering23 (2) (2010) 74ndash82
[9] SA Macpherson SM Iveson KP Galvin Density-based separation in a vibratedRe1047298ux Classi1047297erwithan airndashsand densendashmedium tracerstudies with simultaneousunder1047298owand over1047298ow removal Minerals Engineering 24 (10) (2011) 1046ndash1052
[10] PN Rowe AW Nienow Particle mixing and segregation in gas 1047298uidised beds Areview Powder Technology 15 (2) (1976) 141ndash147
[11] D Geldart Types of gas 1047298uidization Powder Technology 7 (5) (1973) 285ndash292[12] LG Gibilaro PN Rowe A model for a segregating gas 1047298uidised bed Chemical
Engineering Science 29 (6) (1974) 1403ndash1412[13] JF Davidson R Clift D Harrison Fluidization 2nd edn Academic Press Landon
1985[14] NS Naimer T Chiba AW Nienow Parameter estimation for a solids mixing
segregation model for gas 1047298uidised beds Chemical Engineering Science 37 (7)(1982) 1047ndash1057
Table 7
Separation results of 1047297ne coal in a vibrated gas-1047298uidized bed
Separation results minus6+3 mm minus3+1 mm
Feed ash content () 4076 3976
Low separation density ( g cm3) 155 152
High separation density ( g cm3) 189 177
Low density separation E 0225 0195
High density separation E 019 0175
Clean coal ash content () 1556 1442
Clean coal yield () 3662 3750Middlings ash content () 3247 3016
Middlings yield () 2354 2229
Gangue ash content () 7007 7102
Gangue yield () 3984 4021
343 X Yang et al Fuel Processing Technology 106 (2013) 338ndash 343
7172019 Artikel 3
httpslidepdfcomreaderfullartikel-3-568d98f1db858 46
magni1047297cation method and the identi1047297cation is concretely given in
Table 3 At 0 ms particles in the local region investigated are compact
and there are no visible particle motions When a bubble passes through
this region since 165 ms particles in this region become loose and differ-
ent in motion Particle 1 with lower density moves upwards along with
the bubble due to gas drag force while particle 2 and particle 3 settle
through the bubble quickly Since 615 ms in the disturbed region
below the bubble particle 2 settles faster than particle 3 And 1047297nally
after a bubble-driven jigging cycle the three investigated particles at
1065 ms are arranged in the axial direction with particle 1 (clean coal)
in the top particle 3 (middlings) in the middle and particle 2 (gangue)
in the bottom which is extremely consistent with the above description
of the bubble-driven jigging mechanism
46 Separation performance
Fig 7 depicts the segregation patterns corresponding to the opti-
mal segregation performance of the two types of feed coal and the
corresponding values of the aforementioned factors are listed inTable 4 Under this optimal conditions each feed coal is 1047297rstly sepa-
rated at a higher separation density to discharge thegangue andthen
the gangue-free coal is separated at a lower separation density to
produce the clean coal and the middlings The partition distribution of
three products of each feed coal is examined by carrying out the
sink-1047298oat experiments as given in Tables 5 and 6 respectively Based on
these data the partition curves of the two types of feed coal are plotted
in Fig 8 The separation results of the two types of feed coal are given in
Table 7 The probable error E values of minus6+3 mm and minus3+1 mm
size fraction of feed coal are 019ndash0225 and 0175ndash0195 respectively
With the comparison of the E value theminus3+ 1 mmfeed coalhasa better
separation ef 1047297ciency both at a high separation densityand a low one than
the minus6+3 mm feed coal This is because that minus3+1 mm feed coal is
easier to achieve uniform 1047298uidization with good bubbling behavior than
minus6+ 3 mm feed coal For each feed coal the E value at a high separation
density is smaller than that at a low one
5 Conclusion
In this study we focus on utilizing the segregation in a vibrated
gas-1047298uidized bed to provide a solution to the dif 1047297cult problem of 1047297ne
coal separation in a dry process which is greatly meaningful with re-
spect to the utilization of 1047297ne coal for energy resources in North-West
China In this process bubble-driven jigging cycles provide enough
space and time for the particles to segregate in the axial direction
depending on their hindered settling velocity differences The experi-
mental results show that the operational parameters including super1047297-
cial air velocity vibration intensity bed height and1047298uidizing time have
signi1047297cant in1047298uences on the segregation performance and the probablyerror E values of minus6+ 3 mm and minus3+1 mm size fraction of feed coal
are 019ndash0225 and 0175ndash0195 respectively According to the analysis
Fig 6 Particle segregation in a bubble-driven jigging cycle
Table 3
Physical properties of the clean coal middlings and gangue particles
Item Color Luster Shape
Clean coal Black Submetallicvitreous luster Round short-rod ellipse
Middlings Dark gray Bituminous luster Long-rod cuboid
Gangue Gray Dull luster Sheet strip
0 1 2 3 4035
040
045
050
055
060
065
070
075
S
T (min)
-6+3 mm
-3+1 mm
Fig 5 Segregation degree at different 1047298uidizing time
341 X Yang e t al Fuel Processing Technology 106 (2013) 338ndash 343
7172019 Artikel 3
httpslidepdfcomreaderfullartikel-3-568d98f1db858 56
of three product separation results the1047297ne coalseparation in a vibrated
gas-1047298uidized bed system is useful to and more effective for 1047297ne coal
cleaning in drought and cold regions
Acknowledgments
The research work involved in this paper received the 1047297nancial
support by the National Natural Science Foundation (No 51134022
51174203) the Key Project of Chinese National Programs for Fundamen-
tal Research and Development (973 program) (No 2012CB214904) the
National Natural Science Foundation of China for Innovative Research
Group (No 50921002) the Natural Science Foundation of Jiangsu Prov-
ince of China (No BK2010002) the Fundamental Research Funds for
the Central Universities (No 2010QNB11 2010ZDP01A06)
a
b
Fig 7 The optimal segregation patterns of the two types of feed coal
Table 4
Operational conditions leading to the optimal segregation performance of the two
types of the feed coal
Factors minus6+3 mm minus3+1 mm
U lowast 02 015
Γ 023 02
H (mm) 70 70
T (minutes) 2 2
Table 6
The sink-1047298oat results of the products of minus6+3 mm feed coal
Density
fraction
( g cm3)
Product weight fraction () Calculated feedstock () Partition
coef 1047297cient ()
Gangue Middlings Clean
coal
Total Reconcentration High
density
Low
density
minus13 015 054 321 390 375 391 1430
13ndash14 142 497 1825 2464 2322 576 2141
14ndash15 110 537 877 1524 1414 721 3797
15ndash16 072 317 326 716 644 1017 4929
16ndash17 057 174 121 352 295 1628 5915
17ndash18 250 390 144 784 534 3185 7304
+18 3338 385 048 3770 433 8852 8893
Total 3984 2354 3662 10000 6016
Table 5
The sink-1047298oat results of the products of minus3+1 mm feed coal
Density
fraction
( g cm3)
Product weight fraction () Calculated feedstock () Partition
coef 1047297cient ()
Gangue Middlings Clean
coal
Total Reconcentration High
density
Low
density
minus13 020 088 455 563 544 346 1626
13ndash14 087 455 1847 2389 2302 363 1978
14ndash15 098 568 977 1643 1545 597 3675
15ndash16 086 458 315 858 772 997 5927
16ndash17 042 153 069 263 222 1583 6895
17ndash18 212 121 041 374 162 5672 7492
+18 3477 386 046 3910 433 8893 8926
Total 40 21 2229 3750 10000 5979
12 14 16 18 20 22
0
20
40
60
80
100
P a r t i t i o n c o e f f i c i e n t ( )
Density (gcm3)
High-density separation
Low-density separation
-3+1 mm
12 14 16 18 20 22
0
20
40
60
80
100
-6+3 mm
High-density separation
Low-density separation
P a r t i t i o n c o e f f i c i e n t (
)
Density (gcm3)
a
b
Fig 8 Partition curves of the two types of feed coal
342 X Yang et al Fuel Processing Technology 106 (2013) 338ndash 343
7172019 Artikel 3
httpslidepdfcomreaderfullartikel-3-568d98f1db858 66
References
[1] Y Zhao L Tang Z Luo C Liang H Xing W Wu C Duan Experimental and numericalsimulation studies of the 1047298uidization characteristics of a separating gasndashsolid 1047298uidizedbed Fuel Processing Technology 91 (2) (2010) 1819ndash1825
[2] AK Sahu A Tripathy SK Biswal A Parida Stability study of an air dense medium1047298uidized bed separator for bene1047297ciation of high-ashIndian coal International Journalof Coal Preparation and Utilization 31 (3ndash4) (2011) 127ndash148
[3] CH Sampaio W Aliaga ET Pacheco E Petter H Wotruba Coal bene1047297ciation of Candiota mine by dry jigging Fuel Processing Technology 89 (2) (2008) 198ndash202
[4] B Zhang H Akbari F Yang MKMohanty J Hirschi Performance optimizationof the FGX dry separator for cleaning high-sulfur coal International Journal of CoalPreparation and Utilization 31 (3ndash4) (2011) 161ndash186
[5] M Fan Q Chen Y Zhao Z Luo Fine coal (6ndash1 mm) separation in magneticallystabilized 1047298uidized beds International Journal of Mineral Processing 63 (4)(2001) 225ndash232
[6] M Fan Q Chen Y Zhao Z Luo Y Guan Fundamentals of a magnetically stabilized1047298uidized bed for coal separation International Journal of Coal Preparation andUtilization 23 (1) (2003) 47ndash55
[7] Z Luo M Fan Y Zhao X Tao Q Chen Z Chen Density-dependent separation of dry 1047297ne coal in a vibrated 1047298uidized bed Powder Technology 187 (2) (2008)
119ndash
123[8] SA Macpherson SM Iveson KP Galvin Density based separations in the Re1047298uxClassi1047297er with an airumlCsand denseumlCmedium and vibration Minerals Engineering23 (2) (2010) 74ndash82
[9] SA Macpherson SM Iveson KP Galvin Density-based separation in a vibratedRe1047298ux Classi1047297erwithan airndashsand densendashmedium tracerstudies with simultaneousunder1047298owand over1047298ow removal Minerals Engineering 24 (10) (2011) 1046ndash1052
[10] PN Rowe AW Nienow Particle mixing and segregation in gas 1047298uidised beds Areview Powder Technology 15 (2) (1976) 141ndash147
[11] D Geldart Types of gas 1047298uidization Powder Technology 7 (5) (1973) 285ndash292[12] LG Gibilaro PN Rowe A model for a segregating gas 1047298uidised bed Chemical
Engineering Science 29 (6) (1974) 1403ndash1412[13] JF Davidson R Clift D Harrison Fluidization 2nd edn Academic Press Landon
1985[14] NS Naimer T Chiba AW Nienow Parameter estimation for a solids mixing
segregation model for gas 1047298uidised beds Chemical Engineering Science 37 (7)(1982) 1047ndash1057
Table 7
Separation results of 1047297ne coal in a vibrated gas-1047298uidized bed
Separation results minus6+3 mm minus3+1 mm
Feed ash content () 4076 3976
Low separation density ( g cm3) 155 152
High separation density ( g cm3) 189 177
Low density separation E 0225 0195
High density separation E 019 0175
Clean coal ash content () 1556 1442
Clean coal yield () 3662 3750Middlings ash content () 3247 3016
Middlings yield () 2354 2229
Gangue ash content () 7007 7102
Gangue yield () 3984 4021
343 X Yang et al Fuel Processing Technology 106 (2013) 338ndash 343
7172019 Artikel 3
httpslidepdfcomreaderfullartikel-3-568d98f1db858 56
of three product separation results the1047297ne coalseparation in a vibrated
gas-1047298uidized bed system is useful to and more effective for 1047297ne coal
cleaning in drought and cold regions
Acknowledgments
The research work involved in this paper received the 1047297nancial
support by the National Natural Science Foundation (No 51134022
51174203) the Key Project of Chinese National Programs for Fundamen-
tal Research and Development (973 program) (No 2012CB214904) the
National Natural Science Foundation of China for Innovative Research
Group (No 50921002) the Natural Science Foundation of Jiangsu Prov-
ince of China (No BK2010002) the Fundamental Research Funds for
the Central Universities (No 2010QNB11 2010ZDP01A06)
a
b
Fig 7 The optimal segregation patterns of the two types of feed coal
Table 4
Operational conditions leading to the optimal segregation performance of the two
types of the feed coal
Factors minus6+3 mm minus3+1 mm
U lowast 02 015
Γ 023 02
H (mm) 70 70
T (minutes) 2 2
Table 6
The sink-1047298oat results of the products of minus6+3 mm feed coal
Density
fraction
( g cm3)
Product weight fraction () Calculated feedstock () Partition
coef 1047297cient ()
Gangue Middlings Clean
coal
Total Reconcentration High
density
Low
density
minus13 015 054 321 390 375 391 1430
13ndash14 142 497 1825 2464 2322 576 2141
14ndash15 110 537 877 1524 1414 721 3797
15ndash16 072 317 326 716 644 1017 4929
16ndash17 057 174 121 352 295 1628 5915
17ndash18 250 390 144 784 534 3185 7304
+18 3338 385 048 3770 433 8852 8893
Total 3984 2354 3662 10000 6016
Table 5
The sink-1047298oat results of the products of minus3+1 mm feed coal
Density
fraction
( g cm3)
Product weight fraction () Calculated feedstock () Partition
coef 1047297cient ()
Gangue Middlings Clean
coal
Total Reconcentration High
density
Low
density
minus13 020 088 455 563 544 346 1626
13ndash14 087 455 1847 2389 2302 363 1978
14ndash15 098 568 977 1643 1545 597 3675
15ndash16 086 458 315 858 772 997 5927
16ndash17 042 153 069 263 222 1583 6895
17ndash18 212 121 041 374 162 5672 7492
+18 3477 386 046 3910 433 8893 8926
Total 40 21 2229 3750 10000 5979
12 14 16 18 20 22
0
20
40
60
80
100
P a r t i t i o n c o e f f i c i e n t ( )
Density (gcm3)
High-density separation
Low-density separation
-3+1 mm
12 14 16 18 20 22
0
20
40
60
80
100
-6+3 mm
High-density separation
Low-density separation
P a r t i t i o n c o e f f i c i e n t (
)
Density (gcm3)
a
b
Fig 8 Partition curves of the two types of feed coal
342 X Yang et al Fuel Processing Technology 106 (2013) 338ndash 343
7172019 Artikel 3
httpslidepdfcomreaderfullartikel-3-568d98f1db858 66
References
[1] Y Zhao L Tang Z Luo C Liang H Xing W Wu C Duan Experimental and numericalsimulation studies of the 1047298uidization characteristics of a separating gasndashsolid 1047298uidizedbed Fuel Processing Technology 91 (2) (2010) 1819ndash1825
[2] AK Sahu A Tripathy SK Biswal A Parida Stability study of an air dense medium1047298uidized bed separator for bene1047297ciation of high-ashIndian coal International Journalof Coal Preparation and Utilization 31 (3ndash4) (2011) 127ndash148
[3] CH Sampaio W Aliaga ET Pacheco E Petter H Wotruba Coal bene1047297ciation of Candiota mine by dry jigging Fuel Processing Technology 89 (2) (2008) 198ndash202
[4] B Zhang H Akbari F Yang MKMohanty J Hirschi Performance optimizationof the FGX dry separator for cleaning high-sulfur coal International Journal of CoalPreparation and Utilization 31 (3ndash4) (2011) 161ndash186
[5] M Fan Q Chen Y Zhao Z Luo Fine coal (6ndash1 mm) separation in magneticallystabilized 1047298uidized beds International Journal of Mineral Processing 63 (4)(2001) 225ndash232
[6] M Fan Q Chen Y Zhao Z Luo Y Guan Fundamentals of a magnetically stabilized1047298uidized bed for coal separation International Journal of Coal Preparation andUtilization 23 (1) (2003) 47ndash55
[7] Z Luo M Fan Y Zhao X Tao Q Chen Z Chen Density-dependent separation of dry 1047297ne coal in a vibrated 1047298uidized bed Powder Technology 187 (2) (2008)
119ndash
123[8] SA Macpherson SM Iveson KP Galvin Density based separations in the Re1047298uxClassi1047297er with an airumlCsand denseumlCmedium and vibration Minerals Engineering23 (2) (2010) 74ndash82
[9] SA Macpherson SM Iveson KP Galvin Density-based separation in a vibratedRe1047298ux Classi1047297erwithan airndashsand densendashmedium tracerstudies with simultaneousunder1047298owand over1047298ow removal Minerals Engineering 24 (10) (2011) 1046ndash1052
[10] PN Rowe AW Nienow Particle mixing and segregation in gas 1047298uidised beds Areview Powder Technology 15 (2) (1976) 141ndash147
[11] D Geldart Types of gas 1047298uidization Powder Technology 7 (5) (1973) 285ndash292[12] LG Gibilaro PN Rowe A model for a segregating gas 1047298uidised bed Chemical
Engineering Science 29 (6) (1974) 1403ndash1412[13] JF Davidson R Clift D Harrison Fluidization 2nd edn Academic Press Landon
1985[14] NS Naimer T Chiba AW Nienow Parameter estimation for a solids mixing
segregation model for gas 1047298uidised beds Chemical Engineering Science 37 (7)(1982) 1047ndash1057
Table 7
Separation results of 1047297ne coal in a vibrated gas-1047298uidized bed
Separation results minus6+3 mm minus3+1 mm
Feed ash content () 4076 3976
Low separation density ( g cm3) 155 152
High separation density ( g cm3) 189 177
Low density separation E 0225 0195
High density separation E 019 0175
Clean coal ash content () 1556 1442
Clean coal yield () 3662 3750Middlings ash content () 3247 3016
Middlings yield () 2354 2229
Gangue ash content () 7007 7102
Gangue yield () 3984 4021
343 X Yang et al Fuel Processing Technology 106 (2013) 338ndash 343
7172019 Artikel 3
httpslidepdfcomreaderfullartikel-3-568d98f1db858 66
References
[1] Y Zhao L Tang Z Luo C Liang H Xing W Wu C Duan Experimental and numericalsimulation studies of the 1047298uidization characteristics of a separating gasndashsolid 1047298uidizedbed Fuel Processing Technology 91 (2) (2010) 1819ndash1825
[2] AK Sahu A Tripathy SK Biswal A Parida Stability study of an air dense medium1047298uidized bed separator for bene1047297ciation of high-ashIndian coal International Journalof Coal Preparation and Utilization 31 (3ndash4) (2011) 127ndash148
[3] CH Sampaio W Aliaga ET Pacheco E Petter H Wotruba Coal bene1047297ciation of Candiota mine by dry jigging Fuel Processing Technology 89 (2) (2008) 198ndash202
[4] B Zhang H Akbari F Yang MKMohanty J Hirschi Performance optimizationof the FGX dry separator for cleaning high-sulfur coal International Journal of CoalPreparation and Utilization 31 (3ndash4) (2011) 161ndash186
[5] M Fan Q Chen Y Zhao Z Luo Fine coal (6ndash1 mm) separation in magneticallystabilized 1047298uidized beds International Journal of Mineral Processing 63 (4)(2001) 225ndash232
[6] M Fan Q Chen Y Zhao Z Luo Y Guan Fundamentals of a magnetically stabilized1047298uidized bed for coal separation International Journal of Coal Preparation andUtilization 23 (1) (2003) 47ndash55
[7] Z Luo M Fan Y Zhao X Tao Q Chen Z Chen Density-dependent separation of dry 1047297ne coal in a vibrated 1047298uidized bed Powder Technology 187 (2) (2008)
119ndash
123[8] SA Macpherson SM Iveson KP Galvin Density based separations in the Re1047298uxClassi1047297er with an airumlCsand denseumlCmedium and vibration Minerals Engineering23 (2) (2010) 74ndash82
[9] SA Macpherson SM Iveson KP Galvin Density-based separation in a vibratedRe1047298ux Classi1047297erwithan airndashsand densendashmedium tracerstudies with simultaneousunder1047298owand over1047298ow removal Minerals Engineering 24 (10) (2011) 1046ndash1052
[10] PN Rowe AW Nienow Particle mixing and segregation in gas 1047298uidised beds Areview Powder Technology 15 (2) (1976) 141ndash147
[11] D Geldart Types of gas 1047298uidization Powder Technology 7 (5) (1973) 285ndash292[12] LG Gibilaro PN Rowe A model for a segregating gas 1047298uidised bed Chemical
Engineering Science 29 (6) (1974) 1403ndash1412[13] JF Davidson R Clift D Harrison Fluidization 2nd edn Academic Press Landon
1985[14] NS Naimer T Chiba AW Nienow Parameter estimation for a solids mixing
segregation model for gas 1047298uidised beds Chemical Engineering Science 37 (7)(1982) 1047ndash1057
Table 7
Separation results of 1047297ne coal in a vibrated gas-1047298uidized bed
Separation results minus6+3 mm minus3+1 mm
Feed ash content () 4076 3976
Low separation density ( g cm3) 155 152
High separation density ( g cm3) 189 177
Low density separation E 0225 0195
High density separation E 019 0175
Clean coal ash content () 1556 1442
Clean coal yield () 3662 3750Middlings ash content () 3247 3016
Middlings yield () 2354 2229
Gangue ash content () 7007 7102
Gangue yield () 3984 4021
343 X Yang et al Fuel Processing Technology 106 (2013) 338ndash 343