Formulas Kiln

(1)

Residence time in Kiln “t” = 1.77 (Phy)^1/2 L ________________

Alpha* D*N

Phy =Angle of repose for lime stone ~ 36 Degree

L = length of Kiln in meter Alpha = Kiln inclination in %

D = Effective diameter of Kiln in meter N = Rotation per minute rpm

(2)

Precalcination Zone = 2 min Calcination Zone = 10-12 min Burning Zone = 6 – 8 min Cooling Zone = 2 min

Preheater Zone = 1 min A B C D F = t = 20 -28 Minutes B C D A E Kiln Inlet Kiln Outlet 7.5m/sec

Mat velo Max

4.5m/sec Mat Velo Min

(3)

12 CaO Lime stone 2 SiO2 Silica oxide 2 Al2O3 Aluminium oxide Fe2O3 Iron oxide 1450*C 3Cao.SiO2 (C3S) Alite 2CaO SiO2 (C2S) Belite 3 CaOAl2O3 (C3A) Tricalcium Aluminate 4CaO.Al2O3.Fe2O3 (C4AF) Tetra Calcium Alumino Ferrite CLINKERISATION

(4)

**100* CaO**

LSF =

(2.8 SiO

2 + 1.18 Al

2 O

3 + 0.65 Fe

2 O

3 )

0.66 > LSF < 1.2

= =

LIME SATURATION FACTOR

(5)

SiO2

SR =

(Al2O3 + Fe2O3)

2.2 > SR < 2.6

= =

SILICA RATIO

(6)

Al2O3

AR =

Fe2O3

1.5 > AR < 2.5

= =

ALUMINA RATIO

AR < 1.5 IS CALLED FERROCEMENTS

(7)

CALORIFIC VALUE OF COAL

LHV = HHV – 50.1H – 5.6 M – 0.191O

H = % HYDROGEN

M = % MOISTURE O = % OXYGEN

LHV = LOW HEATING VALUE Kcal /Kg

HHV = HIGH HEATING VALUE Kcal /Kg

KCal / Kg x 4.187 x 10^(-3) = MJ/Kg

KCal / Kg x 1.8 = Btu / lb

ultimate analysis

(8)

COAL USED IN CEMENT INDUSTRY

• LHV = 6500 – 7000 Kcal / Kg

• ASH = 12~15 %

• VOLATILE MATERIAL = 18~ 22 %

(9)

D =Diameter in Meter

L = Length in meter

WEIGHT OF CYLINDRICAL( kiln) SHELL = W

(10)

THERMAL EXPANSION OF SHELL

A = Alpha x T x L

Alpha for steel (coefficient of linear expansion = 1.2x 10^ (-5) mm per Meter

T= dT =( Average temp – Ambient temp) Degre centigrade

L= Length of (Kiln) Shell

=L1 + L2 T2a T2bb T1 A1= (T2a+T1)/2 - T A1= (T2b+T1)/2 - T Ambient temp = T Skin Temperature Diagram L1 L2 A = A1 +A2 X L1 X L2

(11)

KILN SPECIFIC VOLUME LOADING =

TPD/ m3

or Specific Kiln capacity ~ 2.3 t / m3 at Kiln circumferential speed = 50 cm / sec

KILN SPECIFIC THERMAL LOADING = Kcal / m2.hr

Specific Kiln thermal loading

Qp

= 1.4 x 10 ^ 6 x D Kcal / m2. hr

Qp

should not exceed 3.46 x 10^6 Kcal/m^2.hr

COOLER SPECIFIC LOADING or Specific Cooler Capacity =

TPD/ m2

= 38 -43 metric ton of clinker per m^2 .24 hr

IMPOTANT PARAMETERS

(12)

KILN CAPACITY ASSESMENT

•Capacity of ID fan.

•Preheater cyclone design.

•Proclaimed Design & Volume.

•Kiln inclination & Volume.

•Kiln % filling, Specific volume loading &.Thermal

loading.

•Kiln Drive capacity.

(13)

For Gears:

Pitch Diameter = Module x No. of Teeth Blank Diameter = Module x (No of Teeth+2)

For Airslide Cloth

• Fabric Polyester 100%.

• Min=140*C & Max = 260*C.

• Permeability = 400m3/hr-m2 or 6m3/min-m2. at 80mbar

• Tensile strength : WEFT = 1200 Kg/cm2 : WARP = 600 Kg/cm2 • Air Required = 2.5-3.0(Closed type), (2 Cone silo Bins),(1.5Open Type)

(14)

V VI V IV III II IA IB Twin cyclones Twin cyclones PH fan-1 PH fan-2 Riser Duct KILN Girth gear SLC T.A.Duct I _II III 950*C PYRO STRING KILN STRING

(15)

CEMENT MILL FORMULAS

MILL CRITICAL VELOCITY = 76 / (D)^1/2

(16)

H D

MILL CROSS SECTION

H = 0.16D

Mill charging:

Dynamic Angle of Repose = 35 degree 20 minutes with Horizontal (Theta ) Theta

OR

Dynamic Angle of Repose = 54 degree 40 minutes with Vertical (Theta )’ Theta’

(17)

GRINDING MEDIA LOAD “ G”

G = 4620(R)^2.L

TAGGARTS FORMULA

Sy = specific gravity of ball 7.8-7.9 Ton / m3 gm = Bulk density of charge 4.5 Ton / m3 . Pi = 22/7 or 3.14 Constants:

G = gm.Sy.Pi. (R)^2.L

4

(18)

POWER CONSUMPTION OF MILL = P

P= 12G

SEPARATOR A %fines/F B%fines/D C%fine/G A % fines of separator feed

B % fines of Tailings/Reject C % fines of finished Product F TPH of separator feed D TPH of Tailings/Reject G TPH of finished Product s Ball Mill Seperator efficiency

n = C (A-B)

A(C-B))

L= G/D=A-C

B-A F = L(1+D)

1.

2. 3.

(19)

L / D = 3 Two Compartment Mill L / D = 4.5 Three Compartment Mill

Carman Lining Slegton – Magotteaux Lining Lining FLS Lining Classifying Liners

(20)

Important Conversions

1 Barrel = 42 Gallons = 159 litres = 5.615 Cuft

1 Kcal = 4.187 J KCal / Kg x 1.8 = Btu / lb

Characteristic OPC-43(IS8112) OPC-43(IS12269) PPC- (IS1489)Part-1

Blaine 225 225 300

3 Days(MPa) 23 27 16

7 Days 33 37 22

(21)

70 *

H L

L=H/2

(22)

(23)

(24)

(25)

GASCONDITIONING TOWER SPRAY

TOP VIEW

(26)

(27)

(28)

Kiln Data :

4.4 meter Diameter x 60 meter length Inclination = 3.5%

Shell thicknesses = 25 mm , 28 mm , 35 mm , 65 mm Kiln speed = 3.5 to 5.25 RPM

Preheater : Type : 6440 / PR 7044 VI Stage

2200 m

3500 m

2000 m

3200 m

Dip tube

(Diameter)

4400 m

7000 m

4000 m

6400 m

I Cyclone Twin

(Diameter)

Pyro string

Kiln string

Desc

(29)

Girth Gear :

Module = 39

No of Teeth = 148

Material of construction = CS 640 (Normalized Cast Steel) Dimensions = 550 mm (width)

Pinion :

Module = 39

No of Teeth = 28

Material of construction = 30 Cr Ni Mo V8 (Normalized CastSteel) Dimensions = 600 mm (width)

(30)

Tyre Assemblies three no’s :

Material of construction = GS 24 Mn 5 (Normalized Cast Steel) Dimensions = 5620 OD x 4581 ID x 775 (width)

Supporting Rollers Assemblies three no’s :

Material of construction = CS 640 (Normalized Cast Steel) Dimensions = 5620 OD x 4581 ID x 775 (width) Main Drive Tyre Supporting Roller Girth Gear Pinion Kiln Shell

(31)

Kiln Main Drive : Gear box = SDN 800 Ratio = 54.35:1 Motor KW = 710 Input RPM = 100 - 1000 Aux G.B SDA 250 54.35: 1 Motor 30 KW ; 1500 RPM Motor G.B Kiln Axis G.G Pinion Motor _G.B RWN-500 Concord Alingnomatic Geared Coupling RWB-178

(32)

(33)

(34)

MID KILN FEEDING

(35)

(36)

Degree Of Kiln filling & Kiln Cross Sectional loading:

% of Filling

or

Kilns Degree

Area of this segment (

A

1

)

=

Area of cross section of Kiln (

A

)

Segment

Theta 4.5 70 5.42 75 6.52 80 7.75 85 9.09 90 10.7 95 12.1 100 13.75 105 15.65 110 % of Kiln filling Centric Angle Theta

(Degree)

r^2 2

O – Sin O

A1 =

r = radius inside lining

(37)

13

12

11

10

9

2.0

3.0

3.5

4.0

4.5 Theta

%

Note : In practical Kiln operation the kiln load should not exceed 13%,since higher Kiln loads impair the heat tranfer

Rotary Kiln Slope versus Load

Thumb rule by

Bohman

> 3.4 m 3 3 m to 3.4 m 4 up to 2.8 m 5 Kiln diameter (m) % Kiln Slope

Material velocity in kiln

1). Burning Zone = 4.5 mm / sec Lowest

(38)

Rotary Kiln power input calculation :

W x bd x td x N x F x 0.0000092

rd

H.P =

W = Total vertical load on all roller shaft bearing,lb bd = roller shaft bearing diameter , inches

rd = roller diameter , inches

td = tire or riding rind diameter , inches N = rpm of Kiln shell

P = Coefficient or friction of roller bearings , 0.018 for oil lub bearings & 0.06 for grease lub bearings

1

This is Frictional Horse Power 1

(39)

This is Load Horse Horse Power 2

(D x Sin O) ^3 x N x L x K

H.P

=

2

D = Kiln dia .inside lining , ft

Sin O = read from diagram depending on %Load

N = rpm of Kiln shell

L = length of kiln in ft

K = 0.00076

_{Total power =}

₁ ₂

(40)

Arun Shourie

Relation Manager - Insurance

Dir: +91 (22) 4086 3835 / +91 99200 29366

Cement Monthly - Edelweiss

(41)

D

d

L

v

H

Burner Pipe

Location

40*

(42)

Kiln Diameter = D

Kiln lining thickness = a

Kiln Coating thickness = b

Angle of Repose of kiln load = O = 40* say

Kiln Load = K % Value from table below

Depth of bed in Kiln = Y % To be measured

D – a – b

2 X

K %

=

Z

V

=

Z Cos

O

H

=

Z

Sine

O

21 19.8 1.8.8 17.7 16.7 15.6 14.5 13.4 12.2 11 9.75 Depth of material bed in Kiln = Y % 15 14 13 12 11 10 9 8 7 6 5 Kiln load = K %

(43)

Standard Coal Factor : SCF

To determine the approximate combustion air needed to burn

a given unit wt of coal, formula given below can be used when

no ultimate analysis is available. The combustion air

requirement include here 5% of excess air

100 - a

100 B

7000

=

SCF

a = % Moisture in coal ( as fired )

B = Heat value of coal ( Kcal / kg as fired )

Kg of Air

Kg of Coal

(44)

% Loading of Kiln :

C x f x t

d x V

L

₌

C = Capacity of Kiln Ton / hr

f = Ton (Kg) dry feed / Ton ( kg) of Clinker t = residence time

d = Bulk density of dry feed ton (Kg) / m^3

V = Internal volume of kiln in m^3

Theoretical Flame

Temperature fuel oil :

T

Q

Vg x Cp

=

Q = heating value of oil , K cal / kg Vg = Volume of combustion gases , Nm^3 / Kg Cp = Specific heat of combustion gases =0.40 at 2000*C for fuel class “S”

(45)

Rotary kiln Capacity

Martin’s Formula

:

C = 2.826

v

Vg

C =

Kiln Capacity Ton / Hr

V =

Gas Velocity in gas discharge end , m / sec

Vg =

specific gas volume , m^3 / kg clinker

X D^3

(46)

Heat capacity of Rotary kiln

Q = 1.1 x 10 ^ 6 x D ^3 (Kcal / hr)

D =

Mean inside Kiln Diameter on Bricks, m

Kiln Thermal loading at cross

section of burning zone =

Qp =

1

2 =

Q / Fp

Fp =

0.785 x D^2 Inside cross-section of the kiln

burning zone m^2 where D is kiln shell diameter

Q p = 1.4 x 10 ^ 6 x D Kcal / m^2.hr

(47)

Heat transfer in cyclones preheater:

The rule is that the sizes of the gas ducts and of the cyclone should be in accordance with the formula:

V ^ 2

ID ^ 5

=

Constant

V = Gas volume

ID = Inside Diameter of ducts /

cyclones respectively

(48)

Preheater cyclone sizing

(V) ^ 2 x V

t

C

P

4 D = 0.536

D =

cyclone Diameter , m

V

t

= sp. gr. of gas at aver. Temp , Kg / m ^ 3

V =

Gas volume passimg cyclone , m ^ 3 / Sec

C =

Coefficient for pressure drop = 110

P =

Pressure drop in cyclone in mm WG

V

t

= V

0 273 + t + K

273

K = dust concentration in Gas , grams / m^ 3

(49)

70 *

H L

L=H/2

Length of Dip Tube = ½ Gas inlet height Single Stream

Small size high efficiency cyclone

(50)

Theoretical Heat consumption for

clinker burning :zur Strassen formula :

1.4

0.59

2.31 Fe

2

O

3

117

5.11

22.68 SiO

2

18.8

5.86

3.2 H

2

O

488.7

7.646

63.91 CaO

6.8

6.48

1.05 MgO

13.1

2.22

5.92 Al

2

O

3

kcal/kg

Factor Y

X %

Name

Heat Cons

Multiplication

Constituent

+

_

527.4

+

Net

118.4 _

Net %

99.27 Net Kcal / Kg

= 409.0

6.48*MgO

Q

= 2.22 Al203 + 6.48 MgO + 7.646 CaO + 5.86 H2O + 5.11 SiO2 + 0.59 Fe2O3

(51)

Thermal efficiency of cooler = E

A - B A

X 100 E

=

A = Heat loss of clinker leaving the kiln B = Heat loss of the clinker cooler

Secondary Air Temperature = t

3250 (347 – K )

( X . n )

=

K = Heat loss of the cooler , Kcal/Kg clinker

X = Specific Heat consumption of the kiln , Kcal / Kg clinker n = Excess Air number = 1.1