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Preheater calciner systems


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Successul on every level

An optimal process

Todays modern plant preheats raw

meal to calcination temperature in a

multi-stage cyclone preheater. Most

o the calcination process takes place

in a separately red, stationary calciner,

while the remaining calcination and

clinkerization process takes place in

a rotary kiln.

FLSmidth has precisely what cement

producers need to make it an optimal

process. With its low emissions,

fexibility and ease o operation,

the FLSmidth In-Line Calciner (ILC)

preheater has been a success since

its debut in 1976. And thanks to

our continual development o the

system ever since, the ILC is still at

the oreront o technology. Flexible

enough to meet uture demands as

well, the ILC can help plants stay in

the lead or many years to come.

How the ILC preheater works

Raw meal is introduced at the inlet gas

duct to the Stage I (top) cyclones. It is

subsequently preheated by hot,

countercurrent gas fow as it is

continuously collected and passed

down the other cyclone stages in the

preheater to the calciner. Fuel is burned

in the calciner to achieve 92-95% o

the total material calcination beore

collection in the bottom cyclone and

entrance into the kiln. Combustion air

or the calciner is taken rom the kiln

via the riser duct and through a separate

tertiary air duct rom the cooler.

Proven NOx reduction rom high

temperature stage-less combustion

is incorporated into the standard

design o the ILC preheater. Its a very

uncomplicated and eective way to

create low NOx emissions with only

one ring location, one meal split and

one tertiary air stream entering

tangentially to the calciner.

Our design is based on dividing the

meal rom the second-lowest stage

cyclone to the kiln riser and the calciner.

These eed points are separated by an

expanded riser duct that orms a NOx

reducing zone. That is, the calcining

chamber is built (at least partially) into

the kiln riser. All o the calciner uel is

introduced to the kiln riser duct with

less oxygen than required or complete

combustion, thereby orming a reducing

atmosphere.

Above the reduction zone is the main

calciner vessel, which is divided into

two or more sections separated by a

notch. The changes in cross-sectional

areas create turbulence that ensures

eective mixing o uel, raw meal and

gas, improving heat transer and

combustion. The calciner outlet loop

duct ensures optimum gas retention

time, urther mixing and complete uel

combustion.

Optionally, the second- or third-lowest

stage cyclone material can be urther

split to allow or diversion o a portion

o the meal directly into the upper

Key benets

- Eective emission control

- Easy operation

- Highly reliable

- Optimised uel and power

consumption

- Excellent suitability or

low-grade uels

- Flexibile design or easy

upgrades


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section o the calciner. This creates a

hot zone in the lower section o the

calciner that is conducive to burning

dicult uels and urther NOx

reduction.

Design characteristics

Fullcapacityrangeoftodays

plants o 13,000 tpd or more

Builtwithsingleormultiple

preheater strings with up to 6

cyclone stages

Ratioofringincalciner:55-65%

Calcinationatkilninlet:92-95%

Allowablebypassofkilngas:0-60%

Forbypassofkilngasupto100%,

special ILC version applies

Optionalhotzoneinlower

section o calciner

Availablewithorwithoutthe

HOTDISC combustion device

reactor or burning coarse

alternative uels

Operating characteristics

High-efciencycycloneswithlow

pressure drop resulting in low uel

and power consumption

LowestNOx emission rom unique

high-temperature reduction zone

SimultaneouslowCOemission

specially due to calciner notch

and outlet loop duct

Uncomplicatedoperationwith

single entry locations o calciner

uel and tertiary air

Suitableforringbothtraditional

and alternative uels

1 Calciner outlet loop duet

2 Meal dividing gate

or hot zone

3 Meal dividing gate or

NOxreducing zone

4 Calciner vessel notch

5 Optional hot zone

6 Tertiary air inlet

7 NOxreducing zone

8 Optional kiln gas bypass

9 Calciner ring point

1

2

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5

6

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8 95 stage In-Line Calciner

(ILC) preheater


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Creating a system thatmeets unique needs

Burn coarse alternative uels

Increasingly, plants are burning solid

waste uels to achieve a variety o

benets.ByintegratingtheILCwith

our HOTDISC combustion device, it is

possible to achieve unsurpassed uel

fexibility with minimal impact on

process stability and perormance.

The HOTDISC is a sae, simple and

eective combustion device that has

proven to be the best available

technology or substituting calciner

uel with coarse alternative uels.

With the HOTDISC, plants can burn

all kinds o solid waste in sizes up to

1.2 metres. This eliminates the need

or expensive shredding o lumpy

waste material.

An optimal solution

Preheater and calciner design has a

strong infuence on operational

eciency, emissions and ability to

eectively burn dierent types o

uels. Every FLSmidth preheater

calciner system is optimised or the

individual situation in which it is to be

used. FLSmidths decades o

experience in this area enables us to

deliver solutions that are ideal or

each plants specic challenges.

These are some o the key

actors that go into designing

anoptimalsolution:

1. Number o stages/cyclones

FLSmidths preheater calciner

systems are equipped with up to

six stages o cyclones. The number

o stages is normally determined by

the drying requirements in the

dierent grinding systems.

Emission requirements or other use

o the preheater exit gas can also

aect the number o stages, as can

practical matters such as local

building codes/height restrictions.

2. Number o strings

The number o strings o cyclones

is generally related to the plants

capacity requirements the more

capacity needed, the more strings

typically needed. Most commonly,

the system encompasses one or

two strings, but more may be

considered or the largest o

plants. A transition rom one to

two strings relates to the size o

the cyclones and the resulting

volume o the preheater

construction.

3. Size o cyclones

The selection o cyclone sizes is a

balance o having the smallest

cyclone dimensions while

maintaining the lowest overall

pressure drop through the

preheater. This is to minimise the

induced drat (ID) an power

consumption the most power-

consuming part o a kiln system.

The size o cyclones relates to the

maintaining o desired gas velocity

criteria and eciency.

Increasing the preheater cyclone

dimensions reduces the pressure

drop.Butforanygivencyclone

geometry, stable preheater

operation (without raw meal alling

through the riser ducts) requires a

certain minimum gas velocity.

Kiln gases

Ashes/residues

Preheated raw

meal inlet

Alternative

fuel inlet

Tertiary

air

Emergency cold

raw meal inlet

Kiln riser duct

HOTDISC

combustion

device

Rotating disc

Scraper


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Typical process fowsheeto an ILC kiln system

-465 mm WG (4.5 kPa)

293 C

650 C

890 C

478 C

799 C

1000 C

280 C

100 C

material

gas

fuel

1 Raw meal feed

2 Exhaust gas

3 Kiln gas bypass, if any

4 Clinker

5 Kiln burner

6 Calciner burners

7 Tertiary air duct

8 Tertiary air duct damper

9 Cooler excess air


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Preheater components

Cyclones

FLSmidth preheaters have been

based on proven low pressure loss

(LP) cyclones. The unique design o

the LP cyclone ensures high thermal

eciency and low pressure drop while

enabling a fexible and space-saving

layout. LP cyclones have no horizontal

suraces on the inside or material to

accumulate, thereby securing stable

operation. The top stage has a special

geometry to provide the lowest dust

loss while maintaining low pressure

drop. LP cyclones are not just or

completely new preheaters but may

be individually tted to upgrade

existing preheaters.

Central pipes

Central pipes (thimbles) are standard

in all cyclone stages to provide high

separation eciency. The lowermost

cyclones eature a cast, segmented

design with a hanging suspension

system and common elements

throughout. This enables easy

installation and maintenance.

Sluice faps and distribution

boxes

To prevent gas rom bypassing up

through the material pipes between

the cyclone stages, the pipes are

equipped with sluice faps (tipping

valves) designed or ull opening.

Good meal distribution in the cyclone

riser ducts is ensured by adjustable

spreader plates in the distribution

boxes.

Dividing gates

Robust dividing gates are used to

precisely and consistently distribute

meal to the dierent sections o the

riser duct and calciner. One gate is

capable o dividing meal into two,

three, or our dierent streams.

Tertiary air duct damper

To balance the combustion air fow

between the kiln and calciner, a

tertiary air duct damper is provided

or reliable regulation o the tertiary

air gases. The damper design eatures

a solid reractory blade or long,

reliable lie.

Cast segmented central pipe

Tertiary air duct damper

Material pipe sluice flaps

Meal dividing gate

Typical LP

cyclone


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Upgrades andspecial solutions

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1

2

3 4

ILC upgrades

It is possible to upgrade virtually any

existing kiln system into the modern

ILC regardless o whether it comes

rom FLSmidth or another supplier.

This includes not only conventional

suspension preheaters (SP) and other

calciner systems, but also complete

transormations o long dry and wet

kiln systems.

SLC-D preheater calciner system

As an optional preheater calciner system,

FLSmidth also oers the SLC-D. With

its high-temperature pre-combustion

chamber, the SLC-D (Separate-Line

with Downdrat Calciner) oers unique

fexibility in uel use. Choose it as a

new system, or quickly upgrade an

existing ILC or SP preheater.

The separate-line eatures o this

system enable a substantial portion o

the total retention time to be located

parallel to the kiln riser duct. The

placement o the combustion chamber

outside the preheater structure makes

this calciner design well suited or

upgrades, since downtime is minimal.

The SLC-D combines the advantages

o separate-line calciners with the low

NOx eatures o the in-line calciner

when a portion o the calciner uel is

directed to the kiln riser duct.

A hybrid arrangement that combines

the SLC-D with a HOTDISC combustion

device is also available to urther

optimize waste uel ring.

1 Primary ring point

2 Pre-combustion chamber

3 Tertiary air

4 Optional ring point

SLC-D type calciner

Example of an ILC upgrade

into an existing preheater


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Project Centre Denmark

FLSmidth A/S

Vigerslev All 77

DK-2500 Valby

Copenhagen

Tel:+4536181000

Fax:+4536301820E-mail:[email protected]

Project Centre USA

FLSmidth Inc.

2040 Avenue C

Bethlehem,PA18017-2188

Tel:+1610-264-6011

Fax:+1610-264-6170

E-mail:[email protected]

Project Centre India

FLSmidth Private Limited

FLSmidth House

34, Egatoor, Kelambakkam

(Rajiv Gandhi Salai, Chennai)

Tamil Nadu 603 103

Tel:+91-44-47481000Fax:+91-44-27470301

E-mail:[email protected]

www.fsmidth.comCopyright 2011 FLSmidth A/S. ALL RIGHTS RESERVED. FLSmidth is a (registered) trademark of FLSmidth A/S. This brochure makes no offers, representations

or warranties (express or implied), and information and data contained in this brochure are for general reference only and may change at any time.

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