Cement Cooler Process

CLINKER COOLER

The information contained or referenced in this presentation is confidential and proprietary to FLSmidth and is protected by copyright or trade secret laws.

CONTENT • Principle • Types

of cooler

/ Generation of cooler

• Working

principle

• Optimizing

the cooler operation

• Instrumentation

and Control


PRINCIPLE OF COOLER


WHY DO WE NEED A CLINKER COOLER..?? 1. To recuper recuperate ate heat heat from clin clinker ker.. 2. Hot cl clink inker er - diffi difficu cult lt to con conve vey y 3. Hot clin clinker ker shows shows negati negative ve effect effect on grindi grinding ng process process 4. Prop Proper er Cooli Cooling ng improv improves es the the quali quality ty of of Cement Cement

WHY DO WE NEED A CLINKER BREAKER AT THE COOLER DISCHARGE..?? To crush the clinker to the acceptable feed size for cement mill (Ball Mill / VRM).


MODES OF HEAT TRANSFER INVOLVED IN CLINKER COOLING



Conduction



Convection



Radiation

Heat moves to clinker edge by conduction

Heat transfer by radiation and convection

Air flows over clinker cooling surface


TYPES OF FLOW Air

Air

Air Material

Material

Material

Parallel flow

Counterflow

Cross-flow

material material

material air T

T

T

air


TYPES OF COOLER


COOLER TYPES



Planetary cooler



Rotary cooler



Grate cooler 

1st Generation Grate Coolers – conventional grate



2nd Generation Grate Coolers – air-beam grate



3rd Generation Grate Coolers – stationary grate


PLANETARY COOLER

ADVANTAGES Operates without Excess Air

DISADVANTAGES High Clinker Temperature > 150

C

°

Simplicity – Low Investment

No TAD Capability

Common Drive (Only 1.5kwh/MT)

Limited Capacity – No Calciner The information contained or referenced in this presentation is confidential and proprietary to FLSmidth and is protected by copyright or trade secret laws.

ROTARY COOLER

ADVANTAGES Operates without Excess Air

DISADVANTAGES High Clinker Temperature > 225

C

°

Permits TAD Take-off

Separate Drive ~ 3.5 kWh/MT

Low Radiation Losses

Higher Investment and maintenance Cost The information contained or referenced in this presentation is confidential and proprietary to FLSmidth and is protected by copyright or trade secret laws.

1ST GENERATION CONVENTIONAL GRATE COOLERS Advantages of Conventional Grate Cooler Ability to handle large capacities Capable of achieving low clinker temperature Favourable heat recuperation Permits take out of hot tertiary air


2nd GENERATION AIR BEAM TECHNOLOGY COOLER

IKN – Pendulum Cooler FLSmidth – COOLAX – CFG Cooler

Advantages of Air beam technology Cooler Ability to handle large capacities Better recuperation compared to conventional grate cooler Improved Cooling air distribution The information contained or referenced in this presentation is confidential and proprietary to FLSmidth and is protected by copyright or trade secret laws.

3rd GENERATION STATIONARY GRATE COOLER –

FLSmidth – CB Cooler

Polysuis - POLYTRACK

KHD - Pyrofloor

Advantages of Stationary Cooler No fall Through Low Wear Parts Low Cooler Loss Low Maintenance and Power High Efficiency The information contained or referenced in this presentation is confidential and proprietary to FLSmidth and is protected by copyright or trade secret laws.

WORKING PRINCIPLE OF COOLER


Grate Plate Polysuis - POLYTRACK FLSmidth – CB Cooler KHD Cooler - PYROFLOOR

IKN Pendulum Cooler


FLOW REGULATOR


FLOW REGULATOR AND CENVENTIONAL TECHNOLOGY


OPERATION OF FLOW REGULATOR


VELOCITY PROFILE COMPARISION

PASSIVE

ACTIVE – Flow Regulator The information contained or referenced in this presentation is confidential and proprietary to FLSmidth and is protected by copyright or trade secret laws.

Flow regulator PRESSURE DROP


FLSMIDTH CROSS BAR COOLER Advantages of CB Cooler Horizontal Clinker transport Improved Transportation efficiency Highly flexible for new construction and upgrades


MEASUREMENTS & OPTIMISING THE COOLER OPERATION


OPTIMISING THE COOLER

TO ensure the cooler is operated efficiently, the following needs to be monitored 

Cooler Heat Balance.



Cooler Efficiency.



Cooler Losses.


COOLER MASS AND HEAT BALANCE

Cooler Inputs Clinker

Input

Cooling Fan

Air Input

Energy Input

Water

Injection

Cooler Outputs Secondary

and Tertiary Air Calculation

Excess

Air

Clinker

Temperature

Cooler

Radiation


Measurements taken in cooler for cooler heat balance 1. 2. 3. 4.

Cooler air fan flow Cooler excess air fan flow – temperature Tertiary air flow – temperature Clinker temperature. TAD - 3 Cooler excess air - 2 Kiln

Cooler

4

Cooler fans - 1 The information contained or referenced in this presentation is confidential and proprietary to FLSmidth and is protected by copyright or trade secret laws.

Cooler air fan flow measurement

V – Velocity – From Anemometer readings (m/s) A – Cross Section area of fan inlet area (m 2) ρ - Density of air (kg/m3) ρN –Density of air at Normal Conditions – 1.293 kg/m3 t – Temperature of ambient air Ps – Static Pressure at fan inlet


COOLER INPUT Clinker Input The amount of clinker is found by physical measurement of clinker coming out of the cooler including all dust. Clinker Input is considered as 1 kg which is taken as the basis for the Mass & Heat balance. Total Clinker from Drop Test

= 200 TPH

Clinker Input

= 200/200

= 1 kg/kg Clinker

Cooling Air Input Velocities of each fan to be measured at fan inlet using the anemometer. The flow can be found from the formula, Volumetric Flow Rate, Q [m 3/Sec]

= Velocity [m/Sec] x Fan Inlet Area [m 2]

Mass Flow Rate [kg/hr]

= Q [m3/Sec] x Density x [kg/m3] x3600

Specific Mass Flow

= Q [kg/hr] / Total Clinker [kg/hr] = 4,20,000/(200*1000) = 2.1 kg/kg Clinker

Fan Energy Input Power Consumed by all Cooler Fans

= 1198 kw

** The value is at meter , 1 % Line Loss and 5 %

Fan Energy

= 1198/200

Motor Loss is to be subtracted and convert it to heat

= 5.99** kwh/t

(kCal/kg Clinker) by using with 0.86

Water Injection Specific Water Flow [kg/kg Clinker] = Net Water Flow [kg/hr] / Total Clinker [kg/hr] The information contained or referenced in this presentation is confidential and proprietary to FLSmidth and is protected by copyright or trade secret laws.

COOLER OUTPUT SECONDARY AND TERTIARY AIR CALCULATION Typical stoichiometric combustion air amount: LMIN = ~1.42kg air/1000kcal (low heat value) Actual combustion air amount: LCOMBUSTION = LMIN * λ Where: Lambda: λ

1 

1

79.1 

20.9

x

O2 100



CO2



O2

LCOOLER = LCOMBUSTION - LP+T - Σ LFALSE The information contained or referenced in this presentation is confidential and proprietary to FLSmidth and is protected by copyright or trade secret laws.

Cooler Excess Air Fan

   

Flow measurement

–

f – Pitot Tube Constant (0.8-0.85) Pd – Dynamic Pressure (Pa) – from Pitot Tube Measurement g – Acceleration of gravity (m/s 2) A – Cross Section of duct (m2)


COOLER OUTPUT EXCESS AIR The cooler Excess air can be found by measuring the temperature and static pressure at cooler ESP inlet or ESP fan inlet or at Cooler ESP Stack. From Stack Cooler Excess air will be found by back calculation as follows. 1. Gas inlet condition 2. Leak air inlet condition 3. Gas outlet condition


COOLER OUTPUT

Clinker Temperature Clinker temperature is to be measured by taking clinker samples in an insulated closed container. Clinker considered for measurement must be sieved in – 12 mm and + 6 mm sieves. Coating pieces and red hot pieces must be removed. It is recommended to take the samples before Clinker crusher. This is mainly because coating pieces will be crushed in clinker crusher zone and this must be avoided.

Cooler Radiation Cooler radiation is calculated from the surface temperature and surface area. In general cooler radiation for modern cooler will be around 6 kcal/kg Clinker.


Specific heat calculation (Cp)


Summary of measurements Cooler input air – Mass – Temperature Cooler excess air – Mass – Temperature Tertiary Air – Temperature Clinker temperature at cooler outlet Fan Energy

    

Summary of calculation   

Secondary and tertiary air – Mass / Flow Radiation loss Specific heat of all parameter with reference to the measured temperature The information contained or referenced in this presentation is confidential and proprietary to FLSmidth and is protected by copyright or trade secret laws.

Typical Cooler Mass and Heat Balance Input

Flow kg/kg

Temp C

Cp Kcal/kg/ C

Ref = 0

Ref amb.

Clinker

1.000

1450

0.264

383.0

381.3

Dust

0.050

1450

0.264

19.2

19.1

Cooling Air

1.928

10

0.237

4.6

0.0

5.2

5.2

0.0

0.0

411.9

405.4

Fan Energy in kWh/t Water Injection

°

°

5.99 0.000

15

1

Total Heat, In Flow kg/kg

Temp C

Cp Kcal/kg/ C

Ref = 0

Ref amb.

Secondary Air

0.312

1119

0.262

91.5

90.7

Secondary Air Dust

0.020

1119

0.245

5.5

5.4

Tertiary Air

0.703

1020

0.262

187.9

186.2

Tertiary Air Dust

0.030

1020

0.244

7.5

7.4

Excess Air

0.914

375

0.238

81.6

79.4

Excess Air Dust

0.000

375

0.195

0.0

0.0

Clinker

1.000

165

0.194

32.1

30.3

6.0

6.0

0.0

0.0

411.9

405.4

Output

°

°

Radiation Heating + Evaporation of Water Total Heat, Out

0.00

579


AIR LOAD CALCULATIONS Cooler Air Load is the ratio of the amount of air supplied to the cooler loading area.

COOLER SPECIFIC AIR Cooler Specific Air is the ratio of the amount of air supplied to the clinker production.


EXAMPLE FOR AIR LOAD AND SPECIFIC AIR

Air flow

Specific Air

Area

Air Load

Fans m3/min

Kg/min

Kg/Kg Clk

m2

kg/min/m2

FN01-K11

1332.24

1555.74

0.28

13.65

113.97

FN02-K21

923.04

1077.89

0.19

10.92

98.71

FN03-K22

1374.77

1605.40

0.29

16.38

98.01

FN04-K31

860.55

1004.91

0.18

10.92

92.02

FN05-K32

1282.78

1497.98

0.27

16.38

91.45

FN06-K41

1457.404

1700.79

0.304

27.30

62.30

FN07-K51

1393.08

1626.78

0.29

27.30

59.59

FN08-K61

1305.31

1524.29

0.273

27.30

55.83

Total

9929.174

11594

2.077

150.15

Here is an example of air load calculation for a complete cooler. Kiln Feed = 550 TPH Kiln Production=8049 TPD Density= 1.167 kg/m3


COOLER LOADING The cooler loading is defined as the amount of clinker over the grate area.

Cooler Loading for the above example is calculated as

Cooler Type

Maximum Loading (TPD/m2)

Cooling Air (kg/kg Clk)

Rotary Cooler

38

3.3

Grate Cooler

50

2.55

Cross Bar Cooler

46

2.3


COOLER EFFICIENCY 

Better Clinker quality



Higher cooler efficiency - Lower specific fuel consumption



Lower clinker temperature - Handling clinker shall be much more easier



Other Indirect benefits … 

Reduction in PH fan power consumption


COOLER EFFICIENCY The efficiency of a cooler is defined as the relationship between the recuperated heat to the kiln and the total heat transferred to the cooler.

Where, Cooler Loss

= (TKO x SKTKO) + (MEX x TEX x SATEX) + RA

TKO

= Temperature of clinker leaving the cooler

SKTKO

= Specific Heat of Clinker leaving the cooler

MEX

= kg of excess air per kg of clinker

TEX

= Temperature of excess air

SATEX

= Specific heat of excess air

MCA

= kg of cooling air per kg of clinker

TCA

= Temperature of cooling air

SATCA

= Specific heat of cooling air

RA

= Cooler housing radiation in kcal/kg of clinker The information contained or referenced in this presentation is confidential and proprietary to FLSmidth and is protected by copyright or trade secret laws.

What is Cooler efficiency???

Cooler efficiency =

=


Heat Available / Heat Input • Heat content of clinker from kiln (Clinker–1450°C) • Heat

content of cooler air (ambient air)

Cooler


Heat loss   

Heat content of cooler vent gas Radiation Heat content of clinker at exit

Radiation

Cooler


Tertiary Air Cooler / Heat loss

Heat Recuperated

Radiation Secondary Air

Cooler

Heat Input


Basis of Cooler loss



Actual Cooler loss



VDZ Cooler loss



Standard Cooler loss


Actual Cooler loss (ref 0°C)

Actual Cooler loss = Heat Content of clinker at 0°C + Heat Content of excess air at 0°C + Radiation loss


VDZ Cooler loss (ref ambient air °C)

Verein Deutscher Zementwerke

–

German Cement Works Association

VDZ Cooler loss = Heat Content of clinker w.r.t amb°C + Heat Content of excess air w.r.t amb°C + Radiation loss


Standard Cooler loss (ref ambient air °C)

Standard Cooler loss basis •Combustion

air – 1.15 kg/kg clk

Standard Cooler loss (kcal/kg clinker) = Heat Content of clinker w.r.t amb°C + Heat Content of excess air w.r.t amb°C + Radiation loss


OVERALL COMPARISON

Total Cooler Loss

VDZ Cooler Loss (Net Cooler Loss Ref Cooling Air Temperature)

Standard Cooler loss (Normalize) Standard Cooler loss (kcal/kg clinker) °

= Heat Content of clinker w.r.t amb C + °

Heat Content of excess air w.r.t amb C + Radiation loss The information contained or referenced in this presentation is confidential and proprietary to FLSmidth and is protected by copyright or trade secret laws.

ACTUAL LOSS Vs STANDARD LOSS


Summary of cooler performance   

Cooler loss – From heat balance Cooler efficiency – From formula Clinker temperature – From measurement

Cooler parameters

Bench Mark Values

Standard Cooler loss (kcal/kg clinker)

≤ 95

Cooler efficiency (%)

≥ 75%

Clinker temperature (°C)

Your cooler

≤ 65+ambient


Possible reasons for cooler inefficiency      

Grate plates worn out (Applicable for 2 nd generation cooler) Insufficient cooler air Clinker bed – not optimum Too high cooler width / grate load Clinker PSD – Too fine clinker – This shall lead to red river, if not cooled initially. Clinker chemistry


Typical Comparison Table of all Cooler Loss Planetary Cooler

Conventional Grate Cooler

Radiation

97

Excess Air

0

Clinker (150 deg C) Total Loss

Radiation Excess Air (1.85 kg/kg @ 240 deg C)

25

Clinker (90 deg C)

122 kcal/kg

Total Loss

Rotary Cooler 75

Excess Air

0

Total Loss

108 17 131 kcal/kg

Air Beam Grate Cooler

Radiation

Clinker (225 deg C)

6

Radiation

45 120 kcal/kg

6

Excess Air (1.2 kg/kg @ 240 deg C)

70

Clinker (90 deg C)

17

Total Loss

93 kcal/kg

Cross Bar Cooler Radiation

6

Excess Air (1.0 kg/kg @ 240 deg C)

58

Clinker (90 deg C)

17

Total Loss

81 kcal/kg The information contained or referenced in this presentation is confidential and proprietary to FLSmidth and is protected by copyright or trade secret laws.

COOLER LOSS

A TYPICAL COMPARISION STUDY

–

Conventional Cooler

Air Beam Cooler

Cross Bar Cooler

Parameters Mass

Temp

Heat

Mass

Temp

Heat

Mass

Temp

Heat

Kiln Exit

1

1450

383

1

1450

383

1

1450

383

Cooling Air

3.10

35

26

2.55

35

21

2.15

35

18

Sec Air

0.45

1070

126

0.45

1220

145

0.45

1260

150

Tertiary Air

0.65

750

124

0.65

815

135

0.65

870

145

Excess Air

2.0

265

130

1.45

270

95

1.05

295

75

Clinker

1

100

19

1

100

19

1

100

19

Radiation

-

-

11

-

-

11

-

-

11

Total Loss

-

-

160

-

-

125

-

-

105

STD Loss

-

-

130

-

-

100

-

-

85

Note : Mass in kg/kg Clinker , Temp in deg C & Heat in kcal/kg

All the three coolers has the same combustion air but the cooler loss reduced by 55 kcal/kg in Cross Bar cooler when compared to conventional cooler. The excess air which is the major loss in cooler is reduced to 1 kg/kg Clinker and where as heat reduced to heat 75 kcal/kg. The Cooling air input is reduced from 3.10 to 2.15 kg/kg Clinker. The information contained or referenced in this presentation is confidential and proprietary to FLSmidth and is protected by copyright or trade secret laws.

EXAMPLE For clear understanding this can be discussed with an example. Let's consider, P = 200 TPH, NCV = 5500 kcal/kg, then saving in

Note:It

fuel is,

must

be

noted

we

have

projected only the heat savings.

Specific Heat Saving

Heat Saving

Fuel Saved

= Conventional Cooler Loss – SF Cooler Loss

We will have additional savings in

= 160 – 105

electrical consumption because of

= 55 kcal/kg

following reasons.

= 55 x 200 x 1000

Reduction

= 11 x 106 kcal/hr

reduces

the

required

for

= 11 x 106 /5500

input

cooling

number fans

of

required

air fans for

system.

= 2000 kg/hr = 2 tons/hr i.e., 48 tons/day

Subsequent reduction in excess air quantity will gave some benefits in

Assume Cost of 1 ton coal = 53 € Amount Saved per day

in

terms of power savings in cooler

= 53 € x 48

vent fan.

= 2,533 € /day Amount Saved per annum (330 Days) = 76320 € /annum The information contained or referenced in this presentation is confidential and proprietary to FLSmidth and is protected by copyright or trade secret laws.

1st Generation Cooler


2nd Generation Cooler


Cement Cooler Process

Recommend Documents