164530597-3-Roller-Press-Fl-Smidth.pdf

B.1

B: Roller press Comminution manual B:

Contents

Roller press Layout…………………………………………… B.1 Pre-grinding......................... Pre-grinding.......... ...........................B.2 ............B.2 Semi-finish grinding.. grinding................ .......................B.3 .........B.3 Finish grinding grinding.............. ............................. ................... .... B.4 Roller press calculations Symbols.................. Symbols... ............................. .........................B.5 ...........B.5 Formulas Formula s ............... ............................. ......................... ........... B.6 Typical values........ values...................... ......................... ........... B.7

Page B.1

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B.2 Layout

Pre-grinding

Pre-grinding layout  Flow splitter controls ratio between material press and pressed material to ball mill 

 Roller



press specific power consumption: -2 to ~5 kWh/t material to ball mill

 Roller



Page B.2

press circulation factor  Roller press throughput/new feed: 1 - ~ 2.1

Roller press

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B.3 layout

Semi-finish grinding

Semi-finish grinding layout

• Separator controls ratio between material recycled to roller  press and pressed material to ball mill.

• Deagglomeration and separation may be combined in one machine

• Roller press specific power consumption: ~ 6 to ~ 14 kWh/t material to ball mill

•

Roller press circulation factor =

Roller press throughput/new feed: ~ 2,5 - 6 Page B.3

Roller press

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B.4 layout

Finish grinding

Finish grinding layout

• Separator controls ratio between material recycled to roller  press and pressed material to ball mill.

• Deagglomeration and separation may be combined in one machine

• Separator may be divided into a grit separator and separator  working in series

• Roller press specific power consumption (cement grinding): ~14 to ~ 30 kWh/t finished product

•

Roller press circulation factor =

Roller press throughput/new feed : ~ 6 to 14 Page B.4

Roller press

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B.5 Roller press Calculations

Symbols

D: W: n: v: s: F: B:

Roller diameter Roller width Roller speed Roller peripheral velocity Grinding bed thickness Roller force Hydraulic pressure

[m] [m] [rpm] [m/s] [m] [kN] [bar]

Piston area Number of hydraulic cylinders

[m ] [-]

Density of pressed material Torque factor

[kg/m ] [-] [kN/m ]

 A: c:

Ō: µ:

kT: M: N: E: C: P: Page B.5

Specific roller pressure Roller press capacity Power consumption Specific power consumption Roller press circulation factor New feed to roller press

2

3

[t/h] [kW] [kWh/t] [-] [Vh] Roller press

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B.6 Roller press Calculations

Formulas

Total roller force T is calculated from the hydraulic pressure and the number and area of the hydraulic cylinders:

T=c • A • B • 102

[kN]

Specific roller pressure k T is the total force divided by the projected roller area: 2

KT = T/(D • W)

[kN/m ]

Peripheral velocity v of the rollers is calculated from the roller  speed and the roller diameter:

v = P • D • (n/60)

[m/s]

Power consumption N of the roller press is calculated from the applied total force, the peripheral velocity and the rolling torque factor between material and roller surface :

N=µ•T•v

[kW]

or when using the specific roller pressure:

N = u • kT • D • W • v

[kW]

Throughput capacity M of the roller press is calculated from the thickness of the grinding bed, the density of the pressed material, the width of the rollers and the peripheral velocity :

M = 3,6 • s •

•W•v

[t/h]

Specific power consumption E1 applied to the material at each pass through the roller press is the power consumption divided by the throughput capacity: E1 = N/M

[kWh/t]

Roller press circulation factor C is the throughput capacity divided by the new feed rate: C = M/P Specific power consumption E applied to the product from the roller press system (finished product ->r product to ball mill) is the

[-]

specific power consumption applied to the material at each pass through the roller press multiplied by the circulation factor:

E = C • E1 Page B.6

[kWh/t] Roller press

Page B.6 R

oller press

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B.7 Roller press Calculations

Typical values

Typical roller press parameters Roller press velocity Specific roller pressure

[m/s] 2

[kN/m ]

1.3 — 1.6 6000 (Cement and slag) 4500 (Raw materials)

Torque factor Grinding bed

[-] [% of D]

1.8- 2.3

3

2.2- 2.7

Density of pressed materia [t/m ]

Page B.7

0.07 -0.1

Roller press