Cyclone Separation

2105321053828221053210538282

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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LOGO

Gas CycloneGas Cyclone

Apinan SootitantawatApinan [email protected]

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



2. Axial Entry cycloneAxial Entry cyclone จะปอนกาซผสมเขาในทางดานบนของเครอง

อาศยแผนครบ ชวยปรบทศทางใหเปนในแนวเสนสมผส ซงสามารถ

ไ แบงไดเปนสองประเภทยอยคอ

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2. Axial Entry cycloneAxial Entry cyclone

17S.ApinanMultiple CycloneMultiple 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)


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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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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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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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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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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)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


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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


sizeCut xD ==54S.Apinan

5050sizeCut xDp ==

LOGO

Prediction of collection Prediction of collection efficiency efficiency efficiency efficiency


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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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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Number of turns of vortex (Ne)Number of turns of vortex (Ne)

vortexofturnsofNumberNe = ffe

)(1 cLLN +≅ )2

( cbe L

HN +≅

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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


Lapple`graphLapple`graph

1( )250 /1

1)(pip

i dddpG

+=

pp

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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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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

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3.2 ⎟⎟⎠

⎜⎜⎝WH

Dk e


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

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below the gas exit duct calculate from ⎟⎠

⎜⎝WHe


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


The accuracy of each model/approach

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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

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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.

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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

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ขอดและขอจากดของไซโคลนขอดและขอจากดของไซโคลน

ขอด ขอเสย

- คาลงทนและคาเดนเครองตา - ประสทธภาพในการเกบกกสาหรบ

- ไมมสวนใดของอปกรณทตองเคลอนท

ทาใหปญหาในการรกษาบารงนอย

อนภาคทเลกกวา 10 ไมครอนคอนขางตา

- ไมสามารถใชกบอนภาคทมลกษณะหนด

- คาความดนสญเสยคอนขางตา

- เปนอปกรณทรวบรวมและกาจดอนภาค

เหนยว

- อาจมปญหาเกยวกบการกดกรอน

แบบแหง

- การกอสรางคอนขางใชพนทนอย

- สามารถออกแบบใหเหมาะสมกบชวง

ขนาดอนภาคได

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Cyclone Separation

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