Formulas Kiln 504h4t

Residence time in Kiln “t” =

Phy

L

1.77 (Phy)^1/2 L ________________ Alpha* D*N

=Angle of repose for lime stone ~ 36 Degree = length of Kiln in meter

Alpha = Kiln inclination in % D

= Effective diameter of Kiln in meter

N

= Rotation per minute rpm

Kiln

Kiln

Inlet

Outlet

A

B

C

Preheater Zone = 1 min

D

E

A

7.5m/sec Mat velo Max

Precalcination Zone = 2 min

B =

Calcination Zone = 10-12 min

C

Burning Zone = 6 – 8 min

D

Cooling Zone = 2 min

F

t = 20 -28 Minutes

4.5m/sec Mat Velo Min

CLINKERISATION 12 CaO Lime stone

3Cao.SiO2 (C3S) Alite

2 SiO2 Silica oxide

2CaO SiO2 (C2S) Belite

1450*C 2 Al2O3 Aluminium oxide

Fe2O3 Iron oxide

3 CaOAl2O3 (C3A) Tricalcium Aluminate

4CaO.Al2O3.Fe2O3 (C4AF) Tetra Calcium Alumino Ferrite

LIME SATURATION FACTOR

100* CaO LSF = (2.8 SiO2 + 1.18 Al2O3 + 0.65 Fe2O3) 0.66 > LSF < 1.2 = = AR = > 0.64

SILICA RATIO

SiO2 SR = (Al2O3 + Fe2O3) 2.2 > =

SR < 2.6 =

ALUMINA RATIO

Al2O3 AR = Fe2O3 1.5 > =

AR < 2.5 =

AR < 1.5 IS CALLED FERROCEMENTS AR = 0.637 IS CALLED FERRARI CEMENT

CALORIFIC VALUE OF COAL LHV = HHV – 50.1H – 5.6 M – 0.191O

LHV = LOW HEATING VALUE Kcal /Kg HHV = HIGH HEATING VALUE Kcal /Kg M = % MOISTURE

H = % HYDROGEN

KCal / Kg x 4.187 x 10^(-3) = MJ/Kg KCal / Kg x 1.8 = Btu / lb

O = % OXYGEN

ultimate analysis

COAL USED IN CEMENT INDUSTRY • LHV = 6500 – 7000 Kcal / Kg • ASH = 12~15 % • VOLATILE MATERIAL = 18~ 22 % • MOISTURE = UP TO 12 %

D =Diameter in Meter

L = Length in meter WEIGHT OF CYLINDRICAL( kiln) SHELL = W

W = Pi x (L) x (D) x thk (mm) x 7.85 Metric Tons

THERMAL EXPANSION OF SHELL

A = Alpha x

TxL

Skin Temperature Diagram

L= Length of (Kiln) Shell =L1 + L2

Alpha for steel (coefficient of linear expansion = 1.2x 10^ (-5) mm per Meter T= dT =( Average temp – Ambient temp) Degre centigrade L1 A1= (T2a+T1)/2 - T A1= (T2b+T1)/2 - T Ambient temp = T

X L1 X L2

T2bb T1 T2a

A = A1 +A2

L2

IMPOTANT PARAMETERS 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

KILN % FILLING = 04 % Min - 16% Max

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. •System Design, Ducts, GCT, fan position & ESP.

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)

PH fan-1 Twin cyclones IA

PH fan-2 Twin cyclones

IB

II III IV

Riser Duct KILN STRING

V VI V

950*C T.A.Duct SLC

PYRO STRING

KILN I Girth gear

II

III

CEMENT MILL FORMULAS

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

MILL ACTUAL VELOCITY = 32 / (D)^1/2

D

Mill charging:

Theta’ Theta H

H = 0.16D MILL CROSS SECTION

Dynamic Angle of Repose = 35 degree 20 minutes with Horizontal (Theta ) OR Dynamic Angle of Repose = 54 degree 40 minutes with Vertical (Theta )’

GRINDING MEDIA LOAD “ G”

G = gm.Sy.Pi. (R)^2.L 4

G = 4620(R)^2.L TAGGARTS FORMULA

Constants:

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

POWER CONSUMPTION OF MILL = P L= G/D=A-C

2.

B-A

P= 12G

SEPARATOR B%fines/D A %fines/F

Seperator efficiency s

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

C%fine/G

Ball Mill

1. n = C (A-B) A(C-B))

3. F = L(1+D)

L/D=3 L / D = 4.5

Two Compartment Mill Three Compartment Mill

I – Chamber Drag Peb Liners

Carman Lining

Classifying Liners

Slegton – Magotteaux Lining Lining

FLS Lining

Important Conversions

1 Barrel = 42 Gallons = 159 litres = 5.615 Cuft 1 Kcal = 4.187 J

Characteristic Blaine 3 Days(MPa) 7 Days 28 Days

KCal / Kg x 1.8 = Btu / lb

OPC-43(IS8112)

225 23 33 43

OPC-43(IS12269)

225 27 37 53

PPC- (IS1489)Part-1

300 16 22 33

L

H 70 *

L=H/2

Length of Dip Tube = ½ Gas inlet height

Single Stream

ESP ELECTROSTATIC PRECIPITATOR

TOP VIEW

GASCONDITIONING TOWER SPRAY

SIDE VIEW

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

Desc

Kiln string

Pyro string

I Cyclone Twin (Diameter)

4000 m 6400 m

4400 m 7000 m

Dip tube (Diameter)

2000 m 3200 m

2200 m 3500 m

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)

Tyre Assemblies three no’s :

Material of construction = GS 24 Mn 5 (Normalized Cast Steel) Dimensions = 5620 OD x 4581 ID x 775 (width) ing Rollers Assemblies three no’s :

Main Drive

Material of construction = CS 640 (Normalized Cast Steel) Dimensions = 5620 OD x 4581 ID x 775 (width) Tyre ing Roller Girth Gear

Pinion

Kiln Shell

Kiln Main Drive :

Gear box = SDN 800 Ratio = 54.35:1

RWN-500

Motor KW = 710 Aux G.B SDA 250 54.35: 1

Input RPM = 100 - 1000

Motor 30 KW ; 1500 RPM

Motor RWB-178

G.B G.B

Motor

Pinion

Kiln Axis Concord Alingnomatic Geared Coupling

G.G

MID KILN FEEDING

Degree Of Kiln filling & Kiln Cross Sectional loading:

Area of this segment (A1)

% of Filling or Kilns Degree

= Area of cross section of Kiln (A)

Centric Angle Theta (Degree)

% of Kiln filling

110

15.65

105

13.75

100

12.1

95

10.7

90

9.09

85

7.75

80

6.52

75

5.42

70

4.5

Theta

Segment r = radius inside lining

A1 =

r^2

O – Sin O

2

A = II r^2

Rotary Kiln Slope versus Load Theta %

4.5

4.0

3.5

3.0

2.0

9

10

11

12

13

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

Thumb rule by Bohman % Kiln Slope

Kiln diameter (m)

5

up to 2.8 m

4

3 m to 3.4 m

3

> 3.4 m

Material velocity in kiln 1). Burning Zone = 4.5 mm / sec Lowest

2). Calcining Zone = 7.5 mm / sec Max

Rotary Kiln power input calculation :

H.P =

W x bd x td x N x F x 0.0000092

1

rd

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

Note : This is Frictional Horse Power

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 Load Horse 2 Horse Power

H.P = (D x Sin O) ^3 x N x L x K

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

Cement Monthly - Edelweiss From: Arun Shourie [mailto:[email protected]]

Arun Shourie Relation Manager - Insurance Dir: +91 (22) 4086 3835 / +91 99200 29366

Burner pipe centering location and alignment Burner Pipe Location

40* L v H

D

d

D–a–b

X

=

K%

Z

=

V

Z Cos O

H = Z Sine O

2 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 Kiln load = K %

5

6

7

8

9

10

11

12

13

14

15

Depth of material bed in Kiln = Y %

9.75

11

12.2

13.4

14.5

15.6

16.7

17.7

1.8.8

19.8

21

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 Kg of Air

B 7000

=

=

SCF

10.478 SCF

Kg of Coal a = % Moisture in coal ( as fired ) B = Heat value of coal ( Kcal / kg as fired )

% Loading of Kiln :

L

=

Cxfxt dxV

Theoretical Flame Temperature fuel oil : T =

Q Vg x

Q = heating value of oil , K cal / kg 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

Vg = Volume of combustion gases , Nm^3 / Kg = Specific heat of combustion gases =0.40 at 2000*C for fuel class “S”

Rotary kiln Capacity

Martin’s Formula : v 2.826 C = X D^3 Vg C = Kiln Capacity Ton / Hr V = Gas Velocity in gas discharge end , m / sec Vg = specific gas volume , m^3 / kg clinker D = Kiln Diameter on Bricks, m

Heat capacity of Rotary kiln

1 Q = 1.1 x 10 ^ 6 x D ^3 (Kcal / hr) D = Mean inside Kiln Diameter on Bricks, m 2

Kiln Thermal loading at cross section of burning zone = Qp = = 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 Qp should not exceed 3.46 x 10 ^ 6 kcal / m2.hr

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

Preheater cyclone sizing

D = 0.536

(V) ^ 2 x Vt 4

Vt = V0 273 + t + K 273

C P

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

D = cyclone Diameter , m V = Gas volume img cyclone , m ^ 3 / Sec Vt = sp. gr. of gas at aver. Temp , Kg / m ^ 3 C = Coefficient for pressure drop = 110 P = Pressure drop in cyclone in mm WG

Small size high efficiency cyclone

L

H 70 *

L=H/2

Length of Dip Tube = ½ Gas inlet height Pressure drop across cyclone = 55 – 60 mbar

Single Stream

Theoretical Heat consumption Q for clinker burning :zur Strassen formula : Constituent Constituent Name

X

%

Multiplication Factor Y

Al2O3

5.92

MgO

1.05 6.48*MgO6.48 63.91 7.646

CaO

2.22

Heat Cons Net kcal/kg

+ 13.1 + 6.8 + 488.7 + 18.8

H2O

3.2

5.86

SiO2

22.68

5.11

Fe2O3

2.31

0.59

_ 117 _ 1.4

Net %

99.27

Net Kcal / Kg

= 409.0

+ 527.4

_ 118.4

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

Thermal efficiency of cooler = E E=

A-B

X 100

A 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 Cooler fans designed for Specific Volume of 3 – 3.15 st.m^3/Kg clinker

Cooling of kiln Exit Gases (GCT)

Y=

Kg / min.Exit gas x 0.25 ( t 1 – t 2) Kcal / min

H t2 – H t3 t1 = Temperature of Kiln exit gases t2 = Temperature of gas to be achieved or maitained t3 = temperature of water (15*C) H t2 = Heat content of water at t2 H t3 = Heat content of water at t3

Y = Kg Water Spray / min