cyclone separation
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UNIT OPERATIONS IUNIT OPERATIONS IUNIT OPERATIONS IUNIT OPERATIONS I
Separation of Particle from fluid: Cyclone
Separation of Particle from fluid: Cyclonefluid: Cyclonefluid: Cyclone
Apinan SoottitantawatApinan SoottitantawatApinan SoottitantawatApinan [email protected]
SeparationSeparation
There are many cases during the processing and handling of particulatesolids when particles are required to be separated from suspension in asolids when particles are required to be separated from suspension in agas or a liquid. How to separate them ?
Classification of separation techniques according to phases involvedp q g p
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Separation: CycloneSeparation: Cyclone
One of the widely used is Cyclone.
GasGas CycloneCyclone: Separate the particle solid (aerosol) from- GasGas CycloneCyclone: Separate the particle solid (aerosol) fromthe gas.
- HydrocycloneHydrocyclone: Separate the particle solid (aerosol) fromthe liquid.
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SolidSolid--gas separation (Dust Collection)gas separation (Dust Collection)
Purpose of the separationPurpose of the separation1 Ai ll ti t l i fl h l f l t fl1. Air-pollution control, as in fly-ash removal from power-plant flue
gases2. Equipment-maintenance reduction, as in filtration of engine intake
air or pyrites furnace-gas treatment prior to its entry to a contactsulfuric acid plant
3. Safety- or health-hazard elimination, as in collection of siliceous andymetallic dusts around grinding and drilling equipment and in somemetallurgical operations and flour dusts from milling or baggingoperationsoperations
4. Product-quality improvement, as in air cleaning in the production ofpharmaceutical products and photographic film
5 Recovery of a valuable product as in collection of dusts from dryers5. Recovery of a valuable product, as in collection of dusts from dryersand smelters
6. Powdered-product collection, as in pneumatic conveying; the spraydrying of milk eggs and soap; and the manufacture of high purity
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drying of milk, eggs, and soap; and the manufacture of high purityzinc oxide and carbon black
SolidSolid--gas separation (Dust Collection)gas separation (Dust Collection)
• In any application, the size of the particles to be removed from the gas determine the method to be used for their separationdetermine, the method to be used for their separation.
• Generally speaking, particles larger than about 100 mm can be separated easily by gravity settling.
• For particles less than 10 mm more energy intensive methods such as• For particles less than 10 mm more energy intensive methods such as filtration, wet scrubbing and electrostatic precipitation must be used.
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CycloneCyclone
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CycloneCyclone
• ใชแยกอนภาคขนาดใหญ > 10 μm
ไ ใ • กลไกในการแยกอนภาคคอ แรง
เหวยงและ แรงดงดดของโลก
• อนภ าคขอ ง ขอ ง แข ง ต กล ง สอ น ภ า คขอ ง ขอ ง แข งตกล ง ส
ดานลางของเครอง
• กาซจะถกปลอยออกทางดานบน
ของเครอง
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CycloneCyclone
Particles in the gas are subjected to centrifugal forces which move them radiallyoutwards, against the inward flow of gas and towards the inside surface of thecyclone on which the solids separate. The direction of flow of the vortex reversesnear the bottom of the cylindrical section and the gas leaves the cyclone via theoutlet in the top. The solids at the wall of the cyclone are pushed downwards byth t t d t f th lid itthe outer vortex and out of the solids exit.
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CycloneCyclone
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Cyclone: ComponentsCyclone: Components
(cylinder)
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Cyclone: Type of inletCyclone: Type of inlet รปแบบทอทางเขาของไซโคลนรปแบบทอทางเขาของไซโคลน
Tangential entryTangential entry Tangential entryTangential entryWith deflector vanesWith deflector vanes
Helical entryHelical entry InvoluteInvolute entryentryWith deflector vanesWith deflector vanes
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Cyclone: Solid discharge valveCyclone: Solid discharge valve
Rotary valveRotary valveSimple manual slide gateSimple manual slide gate Double flap valueDouble flap value
Discharge screw feederDischarge screw feeder
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Cyclone: Outlet of cycloneCyclone: Outlet of cyclone
InvoluteInvolute scroll outletscroll outlet Rotary valveRotary valveInvoluteInvolute scroll outletscroll outlet Rotary valveRotary valve
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Cyclone: Type of CycloneCyclone: Type of Cyclone
BasedBased onon gasgas inletsinlets::
1. Tangential Entry cyclone Tangential Entry cyclone จะปอนกาซผสมเขาในทางแนวเสนสมผส
ของหนาตดเครอง
15S.ApinanTop inletTop inlet Bottom inletBottom inlet
Cyclone: Type of CycloneCyclone: Type of Cyclone
BasedBased onon gasgas inletsinlets::
2. Axial Entry cycloneAxial Entry cyclone จะปอนกาซผสมเขาในทางดานบนของเครอง
อาศยแผนครบ ชวยปรบทศทางใหเปนในแนวเสนสมผส ซงสามารถ
ไ แบงไดเปนสองประเภทยอยคอ
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Cyclone: Type of CycloneCyclone: Type of Cyclone
BasedBased onon gasgas inletsinlets::
2. Axial Entry cycloneAxial Entry cyclone
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Cyclone: Type of CycloneCyclone: Type of Cyclone
BasedBased onon cyclonecyclone performanceperformance::
1. Conventional cyclone
2. High efficiency cyclone
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ประสทธภาพของไซโคลนแตละประเภทประสทธภาพของไซโคลนแตละประเภท
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สดสวนของไซโคลนมาตรฐาน สดสวนของไซโคลนมาตรฐาน
ชนดของไซโคลน
ไซโคลน ไซโคลนทใช
ไซโคลนอตรา
ประสทธภาพสง ทวไป การไหลสง
Body diameter D/D 1.0 1.0 1.0
Height of inlet H/D 0 44 0 5 0 8Height of inlet H/D 0.44 0.5 0.8
Width of inlet W/D 0.21 0.25 0.35
Diameter of gas De/D 0.4 0.5 0.75
Length of vortex S/D 0.5 0.6 0.85
Length of body Lb/D 1.4 1.75 1.7
Length of cone L /D 2 5 2 0 2 0Length of cone Lc/D 2.5 2.0 2.0
Diameter of dust outlet Dd/D 0.4 0.4 0.4
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LOGO
Over all and Grad Over all and Grad Over all and Grad Over all and Grad efficiency of collector efficiency of collector
( l )( l )(cyclone)(cyclone)
Apinan SootitantawatApinan [email protected]
Efficiency of separationEfficiency of separation
• It is useful to represent the efficiency with which various sizes or grades ofparticles are distributed between the outputs of separation devicesparticles are distributed between the outputs of separation devices.
1. Grade or fractional efficiency2. Overall efficiency
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Total Efficiency and Grade EfficiencyTotal Efficiency and Grade Efficiency
Materials Balance
cf MMM +=fMcf
f Component Balance
Mfmif ,
fccmiffmimi MfMfMf ,, +=M
Mmifcmif , FractionMassfmi =
cM
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Total EfficiencyTotal Efficiency
Total efficiency
ME ct =fM
MEt
MM
McM
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Grade Efficiency G(x)Grade Efficiency G(x)
Grade efficiency G(x)
fM
M MfMM
MMfMf
MM
xGmi
ccmi
fi
cii
,
,
,)( =
cM f
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Know Grade Efficiency G(x) to calculate EtKnow Grade Efficiency G(x) to calculate Et
M MfMG ccmici)(
MME c
t = Mff
MxG
mi
ccmi
feedi
cii
,
,
,)( =
MxGMM )(∑∑feedmii
feediiicct fxG
MMxG
MM
MME ,
, )()(
∑∑∑ ====
fGE )(∑ feedmiit fxGE ,)(∑=26S.Apinan
Know Et to calculate Grade Efficiency G(x)Know Et to calculate Grade Efficiency G(x)
Mf MMf
MfxG
f di
ccmii
,)( =MME c
t =Mf feedmi, MGrade efficiency G(x)
f cmit f
fExG ,)( =
feedmif ,
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Total & Grade Efficiency G(x)Total & Grade Efficiency G(x)
ME c MMM +=M
E ct = cf MMM +=
MfMfMf +=
ifccmiffmimi MfMfMf ,, +=
mi
cmit f
fExG ,)( =
mif
EfEff )1( +−= tcmitfmimi EfEff ,, )1( +−=
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Example: Total & Grade EfficiencyExample: Total & Grade Efficiency
Tests on a reverse flow gas cyclone give the results shown in th t bl b lthe table below:
Lower Upper Mass in feed (g) Coase product size (g)
0 5 10.00 0.10
5 10 15.00 3.53
10 15 25 00 18 0010 15 25.00 18.00
15 20 30.00 27.30
20 25 15.00 14.63
25 30 5.00 5.00
From these results determine the total efficiency of the cyclone and grade efficiency of each particle range
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Solution: Total efficiencySolution: Total efficiency
Lower Upper Di Mass in feed (g) Coase product size (g)0 5 2.5 10.00 0.10 5 10 7.5 15.00 3.53 10 15 12 5 25 00 18 0010 15 12.5 25.00 18.00
15 20 17.5 30.00 27.30
20 25 22 5 15 00 14 6320 25 22.5 15.00 14.63
25 30 27.5 5.00 5.00 Total 100 00 68 56
5668M
Total 100.00 68.56
68.0100
56.68===
MME c
t
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100M
Solution: Grade efficiencySolution: Grade efficiency
MfMMfMf
MM
xGmi
ccmi
feedi
ci ,,)( =fmifeedi,
Lower Upper Di Mass in feed (g) Coase product size (g) G(x)=Mci/Mi0 5 2.5 10.00 0.10 0.0100 5 10 7.5 15.00 3.53 0.2353
10 15 12.5 25.00 18.00 0.7200 15 20 17.5 30.00 27.30 0.9100 20 25 22.5 15.00 14.63 0.9753 25 30 27.5 5.00 5.00 1.0000
Total 100.00 68.56
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Grade efficiency curveGrade efficiency curve
1.00
0.80 , G
(x)
0.60
ficiency ,
0 20
0.40
Grade
Eff
0.00
0.20 G
0 10 20 30Diameter (μm)
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Example: Size distribution and cyclone efficiency Example: Size distribution and cyclone efficiency
Air in a foundry is dusty because of handling sand used to makemolds, shaking castings out of the sand molds, and so on. A, g g ,sample of the workplace air was draw through a cyclone at a rateof 0.15 L/min for a period of 100 s. The sampled air contained 240particles which were counted and size optically on the basis ofparticles, which were counted and size optically on the basis ofdiameter as shown in the table. (density of particle = 1.74 g/cm3)
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Example: Size distribution and cyclone efficiency Example: Size distribution and cyclone efficiency
It has been proposed to remove particle from the air with acyclone whose fractional (grade) efficiency is given below.y (g ) y g
1 Pl t th i di t ib ti f th l i b th f l h1. Plot the size distribution of the sample in both of normal graphand lognormal graph for number and mass basis.
2. Will this cyclone be able to bring the workplace air intoy g pcompliance with the OSHA standard that specifies that themaximum allowable concentration for nonrespirable nusancedust is 15 mg/m3?
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dust is 15 mg/m3?
Solution:Solution:
Dlower Dupper Di ΔD ni fi=ni/Σni hi=fni/ΔD niDp3 fmi=niDp3/ΣniDp3 hmi=fmi/ΔD5 6 5.5 1 0 0.0000 0.0000 0 0.0000 0.000000 6 9 7.5 3 0 0.0000 0.0000 0 0.0000 0.000000 9 13 11 4 2 0 0083 0 0021 2662 0 0002 0 0000499 13 11 4 2 0.0083 0.0021 2662 0.0002 0.000049 13 18 15.5 5 29 0.1208 0.0242 107992 0.0080 0.001596 18 26 22 8 54 0.2250 0.0281 574992 0.0425 0.005311 26 37 31 5 11 84 0 3500 0 0318 2625494 0 1940 0 01763826 37 31.5 11 84 0.3500 0.0318 2625494 0.1940 0.017638 37 52 44.5 15 54 0.2250 0.0150 4758541 0.3516 0.023443 52 73 62.5 21 14 0.0583 0.0028 3417969 0.2526 0.012028 73 103 88 30 3 0.0125 0.0004 2044416 0.1511 0.005036
Total 240 1.000 13532065 1.0000
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Solution:Solution:
0.0350
0 0250
0.0300 ction/μm Number fraction
0.0200
0.0250
r Mass frac
0.0150
tion
/μm o
Mass fraction
0.0050
0.0100
umbe
r fract
0.0000 1 10 100
Nu
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1 10 100Diameter (μm)
Solution:Solution:
2. Will this cyclone be able to bring the workplace air intocompliance with the OSHA standard that specifies that thecompliance with the OSHA standard that specifies that themaximum allowable concentration for nonrespirable nusancedust is 15 mg/m3?g
Step 1: Determine the initial over all dust mass concentration
Lparticles/96060/10015.0
240ionconcentratNumber =×
=
35 mparticles/1060.9ionconcentratNumber ×=
6ionConcentratNumberionconcentratMass
3mDρπ
×=
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massaverageofDiameter=mD
Solution:Solution:
Determine the diameter of average mass
Dlower Dupper Di ΔD ni fn,i=ni/nt niDp3 fiDp35 6 5.5 1 0 0.0000 0 0 6 9 7.5 3 0 0.0000 0 0 9 13 11 4 2 0.0083 2662 11
13 18 15.5 5 29 0.1208 107992 450 18 26 22 8 54 0.2250 574992 2396 26 37 31 5 11 84 0 3500 2625494 1094026 37 31.5 11 84 0.3500 2625494 10940 37 52 44.5 15 54 0.2250 4758541 19827 52 73 62.5 21 14 0.0583 3417969 14242 73 103 88 30 3 0.0125 2044416 8518
( ) 34383/13
3/13
⎟⎞
⎜⎛
∑∑ i dfdn
d i
Total 240 1.000 13532065 56384
( ) 34.38==⎟⎟⎠
⎜⎜⎝
= ∑∑iim df
Nd
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massaverageofDiameter=mD
Solution:Solution:
Determine the initial over all dust mass concentration
35 mparticles/1060.9ionconcentratNumber ×=
6ionConcentratNumberionconcentratMass
3mDρπ
×=
6)1034.38(kg/m17401060.9ionconcentratMass
3635
−××××=
π
335 mg/m3.49kg/m1093.4ionconcentratMass =×= −
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Solution:Solution:
Step 2: The minimumum over all efficiency to pass the standard (concentration for nonrespirable nusance dust is 15 mg/m3)concentration for nonrespirable nusance dust is 15 mg/m3)
Mass Balance
3mg/m3.34152.49 =−=−= finefeedc MMM
334M 6957.03.493.34
minimum, ===MME c
t 3.49M
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Solution:Solution:
Step 3: Determine the actual overall efficiency from gradeefficiencyefficiency
fxGE )(∑= feedmiit fxGE ,)(∑=
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Solution:Solution:
Dlower Dupper Di ni fi=ni/Σni fmi=niDp3/ΣniDp3 G(xi) G(xi)fmiDlower Dupper Di ni fi ni/Σni fmi niDp3/ΣniDp3 G(xi) G(xi)fmi5 6 5.5 0 0.0000 0.0000 0.42 0.0000 6 9 7.5 0 0.0000 0.0000 0.5 0.0000 9 13 11 2 0 0083 0 0002 0 6 0 00019 13 11 2 0.0083 0.0002 0.6 0.0001
13 18 15.5 29 0.1208 0.0080 0.68 0.0054 18 26 22 54 0.2250 0.0425 0.72 0.0306 26 37 31.5 84 0.3500 0.1940 0.8 0.1552 37 52 44.5 54 0.2250 0.3516 0.83 0.2919 52 73 62.5 14 0.0583 0.2526 0.93 0.2349 73 103 88 3 0.0125 0.1511 0.98 0.1481
240 1.000 1.0000 0.8662
8662.0)( , ==∑ feedmiit fxGE
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Solution:Solution:
EE standard,tt EE >
Consequently, the collector is capable of q y, psatisfying the OSHA standard.
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Collectors in seriesCollectors in series แบบอนกรมแบบอนกรม
1fM 2fM 2, −nfM 1, −nfM fMfeedMCyclone 1 Cyclone 2 Cyclone
n-1Cyclone
n
M M 1M Mc
t MME 1
1 =
1cM 2cM 1, −ncM ncM ,
22
ct M
ME = 1,1
−= ncnt
ME ,= nc
t
ME
feedM 1fM2,
1,−
−nf
nt M 1,,
−nfnt M
E
fM 1 M M Mfeed
ft M
ME 1
11 =−1
221
f
ft M
ME =−
2,
1,1,1
−
−− =−
nf
nfnt M
ME
1,
,,1
−
=−nf
nfnt M
ME
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Collectors in seriesCollectors in series แบบอนกรมแบบอนกรม
cME 11 = 2cME = 1, −ncM
E ncME
feedt M
E 11
2f
t ME =
2,
1,1,
−− =
nf
ncnt M
E1,
,,
−
=nf
ncnt M
E
feed
ft M
ME 1
11 =−1
221
f
ft M
ME =−
2
1,1,1
−
−− =−
nf
nfnt M
ME
1
,,1
−
=−nf
nfnt M
ME
2,nf 1,nf
nfcifeed MMM ,∑ +=Mass Balance
ict M
ME ∑= , nf
t MM
E ,1 =−feed
t M feedM,1,21 ...1 − ××××=− nfnfff
t
MMMME
45
1,2,1 −− nfnfffeedt MMMM
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Collectors in seriesCollectors in series แบบอนกรมแบบอนกรม
Therefore121 ffff MMMM
1,
,
2,
1,
1
21 ...1−−
− ××××=−nf
nf
nf
nf
f
f
feed
ft M
MMM
MM
MM
E
)1()1()1()1(1 EEEEE −×−××−×−=− )1()1(...)1()1(1 ,1,21 ntntttt EEEEE ××××= −
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Collectors in parallel: Collectors in parallel: แบบขนานแบบขนาน
M1cM
Cyclone 11fM
1,feedM
feedM fMM
,f
MCyclone 2
2fM2,feedM
2cM
∑∑∑ +=+= cifcififeed MMMMMMass Balance
47
∑∑∑ cifcififeed
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Collectors in parallel: Collectors in parallel: แบบขนานแบบขนาน
M1cM
Cyclone 11fM
1,feedM
feedM fMM
,f
MCyclone 2
2fM2,feedM
2cM
fffeedcit M
MM
MMM
ME −=
−== ∑ 1
48
feedfeedfeedt MMM
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Collectors in parallel: Collectors in parallel: แบบขนานแบบขนาน
M1cM
Cyclone 11fM
1,feedM
feedM fMM
,f
MCyclone 2
2fM2,feedM
2cM
111 1 fc
t MM
MME −== 22
2 1 fct M
MMME −==
49
11 feedfeed MM 22 feedfeedt MM
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Collectors in parallel: Collectors in parallel: แบบขนานแบบขนาน
)1( 111 tfeedf EMM −= )1( 222 tfeedf EMM −=)( 111 tfeedf 222 tfeedf
fif MM ∑feed
fi
feed
ft MM
E ∑−=−= 11
tiif d EM∑ − )1(
f d
tiifeedt M
EME ∑−=
)1(1 ,
feedM
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Grade efficiency curveGrade efficiency curve
1.00
0.80 , G
(x)
0.60
ficiency ,
0 20
0.40
Grade
Eff
0.00
0.20 G
0 10 20 30Diameter (μm)
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ประสทธภาพของไซโคลนแตละประเภทประสทธภาพของไซโคลนแตละประเภท
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Cyclone Grade Efficiency in PracticeCyclone Grade Efficiency in Practice
• There are the another way to show the efficiency of collector/separator as cut diameter (critical size criticalcollector/separator as cut diameter (critical size, critical diameter, xcrit, dpcirt)
• For cyclone, the grade efficiency curve for gas cyclones is y , g y g yusually S-shaped.
• The particle size for which the grade efficiency is 50%, cut size, x50, is often used as a single number measurement of the efficiency of the cyclone.
• x is sometimes simply referred to as the cut size of the• x50 is sometimes simply referred to as the cut size of the cyclone (or other separation device).
• The concept of x50 cut size is useful where the efficiency p 50 yof a cyclone is to be expressed as a single number independent of the feed solid size distribution, such as in
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scale-up calculation.
Cut size/ Cut diameter in cycloneCut size/ Cut diameter in cyclone
1.00
0.80 , G
(x)
0.60
ficiency ,
0 20
0.40
Grade
Eff
0.00
0.20 G
0 10 20 30Diameter (μm)
sizeCut xD ==54S.Apinan
5050sizeCut xDp ==
LOGO
Prediction of collection Prediction of collection efficiency efficiency efficiency efficiency
Apinan SootitantawatApinan [email protected]
Prediction of collection efficiencyPrediction of collection efficiency
• Theoretical approach (Laminar flow)
• Cut diameter approach (Lapple`s method)
• Leith and Licht`s method
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Prediction of collection efficiencyPrediction of collection efficiency
11. Theoretical approach (Laminar flow). Theoretical approach (Laminar flow)
VdN gppeρπ)(
2
WxG gppe
μρ
η9
)( ==
)2
(1 cbe
LLH
vortexofturnsofNumberN +≅=2be H
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Prediction of collection efficiencyPrediction of collection efficiency
Number of turns of vortex (Ne)Number of turns of vortex (Ne)
vortexofturnsofNumberNe = ffe
)(1 cLLN +≅ )2
( cbe L
HN +≅
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Prediction of collection efficiencyPrediction of collection efficiency
2. Cut diameter approach2. Cut diameter approach• A semiempirical approach developed by Lapple used larminar
flow treatment but introduced the concept of a cut size, dp50.p50• Therefore he could fine the cut diameter as
VdN ρπ 2
WVdN gppe
μρπ
η9
5.0 ==
Wμ9
μ
gpep VN
Wdρπμ
29
50 =
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gpeρ
Prediction of collection efficiencyPrediction of collection efficiency
Lapple`graphLapple`graph
1( )250 /1
1)(pip
i dddpG
+=
pp
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Prediction of collection efficiencyPrediction of collection efficiency
3. 3. LeithLeith & & LichtLicht’ s ’ s modelTheoreticalmodelTheoretical approach approach (Laminar flow)(Laminar flow)
• The laminar flow model has limitations, as gas flow in a cyclone is not simply laminar (nor is it fully turbulent, because the boundary layer has a significant depth).
• Leith&Licht have derived the equation which was in the formq
))(2exp(1)( 22/1 +−−== nCDpG ψη ))(p()( p ψηG(Dp) คอ ประสทธภาพในการเกบกกยอยของอนภาค dp
C คอ Configuration parameter
Ψ คอ Impaction parameter V t t
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n คอ Vortex exponent
Parameter of cycloneParameter of cyclone
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Prediction of collection efficiencyPrediction of collection efficiency
3.014.0)(1 ⎟⎞
⎜⎛ TD
2835.2)(1 ⎟
⎠⎞
⎜⎝⎛−=
TDn
D คอ Cyclone diameter (นว)
T คอ อณหภมกาซ(เคลวน)
⎬⎫
−⎟⎞
⎜⎛−+⎥
⎤⎢⎡
⎟⎠⎞
⎜⎝⎛++⎟
⎞⎜⎛ −+
+⎪⎨⎧
⎟⎠⎞
⎜⎝⎛ −⎥⎤
⎢⎡
⎟⎞
⎜⎛−=
SkDLddLkSHSDDC ebbe2222
1112π
⎭⎬⎟
⎠⎜⎝
+⎥⎥⎦⎢
⎢⎣
⎟⎠
⎜⎝
++⎟⎠
⎜⎝
+⎪⎩⎨ ⎟
⎠⎜⎝⎥⎥⎦⎢
⎢⎣
⎟⎠
⎜⎝ DDDDDDDDDDWH
C 132
12
D W H De Lb S คอพารามเตอรของไซโคลนD, W, H, De, Lb, S คอพารามเตอรของไซโคลน
k หาไดจาก 3/12
3.2 ⎟⎟⎞
⎜⎜⎛
=DDk
63S.Apinan
3.2 ⎟⎟⎠
⎜⎜⎝WH
Dk e
Prediction of collection efficiencyPrediction of collection efficiency
3.014.0)(1 ⎟⎞
⎜⎛ TD
2835.2)(1 ⎟
⎠⎞
⎜⎝⎛−=
TDn
D คอ Cyclone diameter (นว)
T คอ อณหภมกาซ(เคลวน)
⎬⎫
−⎟⎞
⎜⎛−+⎥
⎤⎢⎡
⎟⎠⎞
⎜⎝⎛++⎟
⎞⎜⎛ −+
+⎪⎨⎧
⎟⎠⎞
⎜⎝⎛ −⎥⎤
⎢⎡
⎟⎞
⎜⎛−=
SkDLddLkSHSDDC ebbe2222
1112π
⎭⎬⎟
⎠⎜⎝
+⎥⎥⎦⎢
⎢⎣
⎟⎠
⎜⎝
++⎟⎠
⎜⎝
+⎪⎩⎨ ⎟
⎠⎜⎝⎥⎥⎦⎢
⎢⎣
⎟⎠
⎜⎝ DDDDDDDDDDWH
C 132
12
D W H De Lb S คอพารามเตอรของไซโคลนD, W, H, De, Lb, S คอพารามเตอรของไซโคลน
k is the farthest distance that the vortex extends below the gas exit duct calculate from
3/12
3.2 ⎟⎟⎠
⎞⎜⎜⎝
⎛=
WHDDk e
64S.Apinan
below the gas exit duct calculate from ⎟⎠
⎜⎝WHe
Prediction of collection efficiencyPrediction of collection efficiency
And d is the diameter of conical section at k
cbd LLkSDDDd /))(( −+−−=
In addition
( )118
2
+= nDVd gppρψ ( )
18 Dgμψ
ρ คอ ความหนาแนนของอนภาคρp dp คอ ขนาดของอนภาคVg คอ ความเรวกาซเขาสไซโคลน
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gμg คอ ความหนดกาซ
Prediction of collection efficiencyPrediction of collection efficiency
The accuracy of each model/approach
66S.Apinan
Prediction of pressure dropPrediction of pressure drop
บงบอกพลงงานทตองใชในการแยกอนภาคของไซโคลน
คาความดนสญเสยทเพมขนของไซโคลนมผลทาใหประสทธภาพของไซโคลนเพมขนดวย
คาความเรวของอากาศทไหลเขาและคาความดนสญเสยกจะมผลตอประสทธภาพของ
ไซโคลน
1vig HVP 2
21 ρ=Δ
ΔP คอ คาความดนสญเสย, Pa
3ρg คอ ความหนาแนนอากาศ, kg/m3
Vi คอ ความเรวของอากาศทไหลเขาไซโคลน, m/s
H ส ส ใ ป i l t l it h d
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Hv คอ ความดนสญเสยในรปจานวนของ inlet velocity head
Prediction of pressure dropPrediction of pressure drop
⎤⎡⎥⎦
⎤⎢⎣
⎡= 2v D
HWKH⎦⎣ eD
Hv คอ the number of velocity head
K คอ คาคงทมคาเทากบ 16 สาหรบไซโคลนทมทอเขาตามแนวK คอ คาคงทมคาเทากบ 16 สาหรบไซโคลนทมทอเขาตามแนว
สมผส(tangential inlet), มคาเทากบ 7.5 สาหรบไซโคลนทมแผนบงคบ(vane)
H คอ ความสงทอเขาไซโคลน H คอ ความสงทอเขาไซโคลน, m
W คอ ความกวางทอเขาไซโคลน, mD คอ ขนาดของทออากาศออก m
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De คอ ขนาดของทออากาศออก, m
Pressure drop in gas cyclonePressure drop in gas cyclone
• Common ranges of pressure drops are as follows
Low-efficiency cyclones 2-4 in. water
Medium-efficiency cyclones 4-6 in. water
High-efficiency cyclones 8-10 in. water
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Factors that affect to the cyclone efficiencyFactors that affect to the cyclone efficiency
พารามเตอร ความดนสญเสย ประสทธภาพ
เพมขนาดของตวไซโคลน(D) ลดลง ลดลง
เพมความยาวของรปทรงกระบอกและสวนโคน(Lb&Lc) ลดลงเลกนอย เพมขน
เพมขนาดของทออากาศออก(De) ลดลง ลดลง
เพมพนททออากาศเขา(โดยความเรวของอากาศเทาเดม) เพมขน ลดลง
เพมความเรวของอากาศ เพมขน เพมขน
เพมอณหภม(โดยความเรวของอากาศเทาเดม) ลดลง ลดลง
เพมความเขมขนของอนภาค ลดลงเมอความเขมขน
เพมในปรมาณมากๆ
เพมขน
ไ เพมขนาดและ/หรอความหนาแนนของอนภาค ไมมผล เพมขน
70S.Apinan
Cyclones in seriesCyclones in series
• Connecting cyclones in series is often done in practice to iincrease recovery.
• Usually the primary cyclone would be of medium or low efficiency design and the secondary and subsequentefficiency design and the secondary and subsequent cyclones of progressively more efficient design or smaller diameter.
SS71S.Apinan
SeriesSeries
Cyclones in parallelCyclones in parallel
• The x50 cut size achievable for a given cyclone geometry d ti d d ith d iand operating pressure drop decreases with decreasing
cyclone size. • The size a single cyclone for treating a given volume flowThe size a single cyclone for treating a given volume flow
rate of gas is determined by that gas flow rate. • For large gas flow rates the resulting cyclone may be so g g g y y
large that the x50 cut size is unacceptably high.• The solution is to split the gas flow into several smaller
l ti i ll lcyclones operating in parallel. • In this way, both the operating pressure drop and x50 cut
size requirements can be achievedsize requirements can be achieved.
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Cyclones in series and parallelCyclones in series and parallel
Clean gas
ParallelParallel
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ปจจยทมผลตอสมรรถนะ ของ ไซโคลนปจจยทมผลตอสมรรถนะ ของ ไซโคลน
74S.Apinan
ขอดและขอจากดของไซโคลนขอดและขอจากดของไซโคลน
ขอด ขอเสย
- คาลงทนและคาเดนเครองตา - ประสทธภาพในการเกบกกสาหรบ
- ไมมสวนใดของอปกรณทตองเคลอนท
ทาใหปญหาในการรกษาบารงนอย
อนภาคทเลกกวา 10 ไมครอนคอนขางตา
- ไมสามารถใชกบอนภาคทมลกษณะหนด
- คาความดนสญเสยคอนขางตา
- เปนอปกรณทรวบรวมและกาจดอนภาค
เหนยว
- อาจมปญหาเกยวกบการกดกรอน
แบบแหง
- การกอสรางคอนขางใชพนทนอย
- สามารถออกแบบใหเหมาะสมกบชวง
ขนาดอนภาคได
75S.Apinan