Download - Selection of Dense Medium Cyclone
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A th J B
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A th J B
Introduction
The sizing of cyclones for dense medium separation, like most other things inthis industry, is a combination of art and science.
The selection process within itself is not complex, but there are a number offactors which must be taken into consideration to ensure that the cyclone sizewhich has in the best separation efficiency is selected.
Main Cateories
The selection process can be divided into the following main categories i.e.
Inputs
This covers feed parameters, yield, and design parameters which resultin a mass balance.
!iameter
The full range of cyclone diameters which apply to the input data arecalculated.
Constraints
The outputs of the diameter process are then checked against thefollowing constraints:
Top size
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The categories can be graphically depicted as follows:
#ach of the categories will now be considered in greater detail.
Inputs
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#eed
The minimum information reuired is the following:
Tons per hour solids $dry%. &article density of the feed. Top size of the feed being treated.
'n order to ensure the best possible cyclone selection a full feedparticle size distribution is reuired, but is unfortunately not always
available.
$ield
The yield is reuired to determine the cyclone mass balance.
The best possible information can be derived if a feed washability isprovided. This enables the yield to be accurately determined and the
sinks density can be calculated.
(nce again, this information is not readily available for many processesdue to, amongst other factors, the density of separation.
The next test is for the yield to be supplied by the end user. This canbe determined by a mass balance around a plant or the results of pilotscale test work.
'f this is not available, then an estimate will have to be made basedupon similar operations ) applications.
! i P
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!iameters
The next step is to calculate the relevant parameters for all the cyclonediameters which can be used for all the application.
%op si&e
The process starts with the - mm diameter cyclone.
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Figure 1
The cyclone diameter must be incremented until one which can handlethe top size is found.
Cyclone Capacity
" table of cyclone capacities for cyclones fitted with a barrel extensionis shown in Table 1.
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Spigotcapacity
(m3/
-.
4-.
4.
3-.
3.
-.
.
1-.
Standard
5i 2apacity
6.7
13.1
1.
16.3
14./
8.7
1.1
3.3
4.8
38.3
/.7
48.4
37.3
1.
-. 3.-4.7
8.4
.
- 37 4 -1 71 77 81 /
Cyclone !iameter
Figure 2
Please note that both standard and high capacity spigots are available and the
calculation should be done for both. If the available spigot capacity is less than the
required spigot capacity, recalculate N based upon the maximum spigot capacity.
'e Cyclone !iameter
The number of cyclones reuired is the greater of ! and !9. 'f thenumber of reuired cyclones is more than 1, increment the cyclone
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Constraints
The output from the previous category must now be checked against theconstraints that apply to this application.
This is a graphical process to ensure that everything is taken intoconsideration.
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* #iner Comment
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"election
"ll the information reuired to make the final selection is nowavailable.
Materials o- Construction
The standard materials of construction which are available are:
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'f multiple cyclones have to be used, for !, it is possible toensure good distribution. 'f !>4, then it is better to considermodules with individual modules having !,3,4.
Inlet "hape
+here suare and rectangular inlets are available, the followingguidelines apply:
Suare inlets can be used where a large top size must be
accommodated or a low differential is reuired. ?ectangular inlets are used to ensure a high differential. This is
especially helpful for high density separations $>3.% as thecirculating medium density can be reduced and the inventory ofmedium is reduced.
Pulp !istri,ution
+here !>1, a distributor is reuired. " two way distributor can bedesigned to ensure that eual solids and liuid distribution is achieved.0or !>, distribution becomes increasing complex.
!ote that no static distributor can remove a bias which already exists.
#ngineered ceramic tiles are the preferred lining for pulp distributors asthey give good wear life and can easily be designed to fit any
distributor.
E.ample
" l ill t ti th f thi d f ll
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Summary of Results
No
ofCyclones
,TotalVolu 0
!c Inlet shape '"piot capacity
(m/0h)
37 Suare - 38
4 Suare ) ?ect. 3 3
-1 Suare ) ?ect. 6.7
71 Suare ) ?ect. 4.
81 ?ect. 1 /.7
'um,er o- Cyclones
1
36- 34- 3-/-47
3
1
1-
3
m
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Topsize
(mm
Cyclone !iameter
Both the 4 and -1 mm cyclones will be acceptable. 'n termsof distribution, cyclones is better than 3, which would supportthe choice of the -1 mm cyclone. The breakaway size for the-1 mm cyclone is 1.8 mm and the bottom deck is 1.7 mm soperformance will not be sacrificed.
Constraints
%op "i&e
7Suare
?ectangular
- 0eed topsize
4
3-
4/
43 4
34 33
3 3
4 -
1/ 1/
1
- 37 4 -1 71 77 81 /
Cyclone !iameter
32.33/
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Spigot Requirements
Spigotcapacity
(m3/
1.
Standard
5i 2apacity8.7
38.3/.7
48.437.3
?euired
6.713.1
1.
16.314./
1.14.8
1.
3.- 4.7
8.4
1.
.1
- 37 4 -1 71 77 81 /
Cyclone !iameter
'ot a constraint
' 1 2 and !c 1 345 mm
Inlet "hape
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Cyclone o!el
Cyclone
"iameter (mm)
C#$%%&'
#$%
Conclusion
The process ) procedure given provides the designer ) end user with a tool toenable him to properly evaluate and select the correct cyclone for a givenapplication taking all the relevant factors into account.
It all adds up6
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92 95 97 100 103
C#%%&'
#%
88 94
'%%
105 110 115 120 125
'#*
133 137 141 145 149
C$'%%&'
$'%
137 146
'$$
163 171 179 186 193
#%%
207 213 219 225 231
C'%%&'
'%
208 223
#3
249 261 273 284 295
3%$
315 325 334 343 352
C CY CLON ES ( WITH BA RREL) - CAPACITIES ( M3/H Sl urr y )
#ee d 7ead ( as a -uncti on o- Cyclo ne !i ameter )
8! 9! ! 45! 44! 42! 4;! 4
4/- - -1- -6 -4
For Other Co!"t"o# $#e For%ul& ' Sr Root ( H / H* ) + C / C*
& &
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%
246 263
#,*
294 308 322 335 348
3%
372 383 394 405 415
C,'%%&'
,'%
300 321
3%
358 376 393 409 424
3*
453 467 481 494 507
C+%%%&'
+%%
321 343
3
384 402 420 437 454
,%