��������Lime Technologies

TSR

Kilns

Contents Page

LIMESTONE ... TO LIME 4

Twin shaft regenerative process

TSR KILN MODELS 8

Cim-RT kiln rectangular sectionCim-TD kiln «twin-D» sectionCim-RD kiln round section

MAIN FEATURES 16

Loading systemsDischarging systemsRefractory liningFiring systemControl system

WORLDWIDE ASSISTANCE 26

ELIMSTONE

4

Lime is one of the oldest chemicals known to man, itwas used to plaster the pyramids of Egypt and, inthe Roman times, the “Calcis Coctores” (Limeburners), had already studied the shape and thefunction of primordial lime kilns named “fornaxcalcaria”.

From that time, the chemistry & technology of limeand limestone have progressively evolved,although most of the progress has occurred since1900, with the greatest step forward made since1955.

Today, lime is still an irreplaceable and affordablechemical largely used in modern industry: frommetallurgy, to the mining industry, in roads and thebuilding industry, in agriculture, in the chemicalindustry, for the desulphurization of waste gases,water treatment and in many other sectors.

The calcination of limestone is a simple chemicalprocess:

However experience and a well proven design arethe secrets for a successful lime burning project asseveral factors influence the choice of lime kilntechnology:

the raw material quality,the fuel characteristics andthe required specifications of the finishedproduct.

The ideal calcination process features: progressivepreheating (rather than a sharp temperature rise),with a gradual increase in calcination temperatureup to the point at which dissociation is complete,finally cooling down the burnt lime, avoiding asmuch as possible further retention time in order to prevent possible re-carbonation.

represent today the best option forhigh and medium reactivity lime production in termsof:

lower fuel consumption,lower maintenance costs,lower emission rates,higher quality lime.

The TSR kilns

To Lime

5

Lime

CaCO + Heat = CaO + CO3 2

LIMESTONE CHARGING

EXHAUST GAS TO FILTERCOMBUSTION AIR

BURNING SHAFT

CO-CURRENT

FLOW

NON-BURNING SHAFT

COUNTER-CURRENT

HEAT RECOVERY

LIME COOLING AIR

6

ProcessTwin Shaft

Regenerative

The Cimprogetti TSR is a two-shaft vertical kilnwhich utilizes the regenerative process for limecalcination.

When one shaft operates in the burning mode, theother shaft operates in the regeneration (non-burning) mode.Each shaft operates for an equal amount of time inthe burning and regeneration modes.

There are two distinguishing characteristics of theTSR kiln:

the parallel flow of hot gases and stone in theburning zone, which allows a mild burning of thelimestone without over-burning, andthe regenerative preheating of all combustionair using the limestone contained in thepreheating zone of the kiln (in the non-burningshaft) as a heat accumulator.

The two shafts are alternately loaded from the top,with pre-weighted limestone charges.

The fuel is introduced to only one of the two shaftsat a time, at the upper side of the burning zonewhere the material is still un-calcined and canabsorb most of the heat released by thecombustion.The combustion gases travel downwards, inparallel flow with the material and leave the burningshaft through the crossover channel, entering thenon-burning shaft travelling upwards in counterflow with the stone.The off-gases then cross the freshly loadedlimestone in the pre-heating zone located in theupper part of the non-burning shaft, where theytransfer most of their residual heat, before beingvented off at temperatures around 100 °C onaverage.The heat transferred by the hot gases to the freshlimestone in the non-burning shaft, is thenrecovered in the next cycle, from the combustion airentering that shaft from the top, when that givenshaft will shift to burning mode.The shifting between burning and non-burningmodes is called “inversion” and it takes place at setintervals.

In the lower part of the TSR kiln, the hot lime lumpsare progressively cooled down to temperaturesbelow 100 °C by means of cooling air introducedfrom the bottom of both shafts so as to be handledwith standard conveying equipment.

7

8

The TSR kiln family consists of two main groups:

«Direct Crossover» featuring a single and shortchannel placed between the shafts,«Radial Crossover» featuring circular channelsaround the shafts which are then connected in the central part.

The Cimprogetti direct crossover group includes:

the RT series, with rectangular cross section,which represents the “entry level” among theTSR kiln range.the TD series, featuring the exclusivesemicircular section design, which is the naturaltechnical evolution of the rectangular section,for capacities up to 500 tpd.

The Cimprogetti radial crossover group includes:

the RD design with its circular cross section,which represents the state-of-the-art in its fieldand the top of the TSR kiln range.

Models

Direct crossover channel

Radial crossover channel

TSR kilns range

9

KilnTSR

0

100

200

300

400

500

600

700

800

Ca

pa

city

(tp

d)

RD15

RT2

RT3

RT4TD3

TD4

TD5

TD7

TD9

TD11

FS4

FS12

RT5

RD12

DIRECT CROSSOVER GROUP RADIAL CROSSOVER GROUP

10

RectangularCim-RT kiln

Section

The Cim-RT is a twin shaft regenerative kilnfeaturing an improved rectangular cross section.It is the Cimprogetti entry level design in parallel flowregenerative kilns.

The key technological features of the process are:

the efficiency of the regenerative calcinationtechnology, proven by innumerable installationsaround the world;the simple cross section and the use of standardrefractory linings;the option to use all technological innovationsdeveloped for the higher performing TD and RDkiln families, namely for the charging anddischarging systems.

The Cim-RT is the logical choice for smaller plantsand/or specific applications like the mining industrywhen sound technology and reduced investmentare required.

Main performance data

Daily outpt (tons) 100 to 300

Stone grain size (mm) 25 to 100

Fuels gaseous, liquid and pulverized solid fuels

Heat consumption approx. 3520 kJ/kg of productapprox. 840 kcal/kg of product

Reactivity of lime very high to medium

11

12

Twin-DCim-TD kiln

Section

The Cim-TD lime kiln features the patented «D-shaped» shaft cross section and is Cimprogetti’sdistinguishing mark in TSR kilns.

The simplicity of the rectangular cross section andthe performance of the circular cross section arecombined to offer excellent value for moneyperformance.

The advanced semi-circular shape of the shaft, theSRT/ULD pressurized limestone charging anddistribution and the double deck discharge tablesmoving in four directions allow very good burninguniformity.

The Cim-TD kiln is mainly targetted at plants with:

medium and high outputs (300 to 500 tons perday) of burned lime or dolomitic lime orsmaller capacity kilns where a superior limequality (res. CO <1,5%) is a key requirement.2

Moreover, the short interconnecting channelbetween the shafts allows a design with a reducedrequirement for refractory materials and steelstructure.

The Cim-TD kiln is also available in the

iner tone configuration.F S

Main performance data

Daily outpt (tons) 150 to 550

Stone grain size (mm) 20 to 120

Fuels gaseous, liquid and pulverized solid fuels

Heat consumption approx. 3520 kJ/kg of productapprox. 840 kcal/kg of product

Reactivity of lime very high to medium

13

14

RoundCim-RD kiln

Section

To respond to the lime market trend movingtowards larger kiln capacities, Cimprogetti hasdeveloped the Cim-RD kiln design, featuring acircular cross section.

The Cim-RD kiln represents the state-of-the-art inits field while it retains the well proven designfeatures of the other Cimprogetti TSR kilns, formost of the process sub-systems (combustion andcooling air units, hydraulic power-pack, automationand control system logic, etc).

The kiln is made of two cylindrical parts , the uppercylinder, of smaller diameter, where limestonecharging and burning take place, and the largerdiameter lower cylinder where lime cooling and thelime discharge are effected.It features a “free flow” radial channel of adequate cross section, all around the shafts, for anunobstructed hot gas flow from one shaft to theother.

The Cim-RD kiln is also available in the

iner tone configuration.F S

Main performance data

Daily outpt (tons) 400 to 700

Stone grain size (mm) 20 to 120

Fuels gaseous, liquid and pulverized solid fuels

Heat consumption approx. 3520 kJ/kg of productapprox. 850 kcal/kg of product

Reactivity of lime high to very high

15

16

FeaturesThe

Theallows directing the fresh

limestone charges as necessaryto improve distribution and avoidsegregation.

ULD hydraulic distributiondevice

The SRT+ULD new charging system hasintroduced a number of innovations to the TSR kilncharging operation, in order to enhance flexibility,control segregation of materials and distribute thecharges to facilitate uniform calcination of thefinished product.

The table shows thecomparison between thedura t ion o f typ ica lstandard cycles and thee x t e n d e d c y c l e sresul t ing from SRTtechnology.

The allows the charging offresh limestone during the burning cycle (and notduring reversal) as normally made in this type ofkilns.Furthermore, charging is effected in two steps tobetter control the waste gas temperature (whichdetermines the practical limit to the cycle length)and therefore to extend the burning time byreducing the reversal (idle) time.The split charge may allow, in some cases,operation of the kiln with a much wider stonegradation (up to 1:6) by means of charging on asandwich mode without a substantial alteration ofthe kiln operation.In addition to the above, whenever the off-gasesare meant to be re-used for other downstreamprocesses, it is possible to benefit from the sideeffect of increasing the CO stream availability at2

the kiln stack, because of the much reducedreversal frequence and time.

SRT charging device

The Systems

17

Loading

In the, the lime discharge is effected from the

whole perimeter of the discharge tables to thebenefit of a more uniform and undisturbeddownwards flow of the material.This is an unique feature which sets the Cim-TD apart from competitors «direct crossover»kiln design where lime discharge is onlypossible through limited areas of theperimeter.

discharging system for the Cim-TDkiln

18

19

In the ,the lime discharge is effected from the wholeperimeter and it is also possible from the center(optional).

Four independent discharging drawers for eachshaft are foreseen, to allow the maximum controlover the whole discharge section.The cooling air distribution is also optimized andsplit both through the drawers circumference aswell as through the centre cone and the crossdivider in order to achieve the best efficiency withthe minimum cooling air demand.Differently from other designs, the four hydraulicdrawers can be operated independently one byone, two by two, or all together.

The additional flexibility given by the combination ofall three methods is purposely intended to optimizelime discharge even in the most demandingconditions.

discharging system for the Cim-RD kiln

The lime discharged from the drawers, is collectedin the bottom of the kiln itself.In standard regenerative kilns, the lime is thendischarged into collecting hoppers placedunderneath and fed to the product conveyor bymeans of vibrating feeders.As regenerative kilns work in positive pressure, thefinal lime discharge is a batch process which iseffected during the cycles reversal.

Cimprogetti to further enhance the performance ofits kilns which are equipped with the patented SRTcharging system (short reversal time), hasintroduced (optionally) a tight discharge hopperwhich works on the same principles as itsinnovative SRT charging device.

The resulting advantage is that the kiln has a furtherreduced reversal (idle) time with correspondingincrease in firing time.

SystemsDischarging

The

20

Twin-D inner shaft refractory lining

Rectangular inner shaft refractory liningThe

have been designed in orderto further improve the flow ofmaterial and hot gas, thecorners are rounded with theuse of 100% standard bricks.The refractory lining issubstant ia l l y made ofcommercial shapes availablefrom suppliers worldwide.

«Rounded corners» ofthe Cim-RT and Cim-TDcrossover channel kiln

The heart of a lime kiln is definitely its refractorylining, which should ideally be simple and robust,so as to be easily built everywhere in the world.

As shown in the side page, both the RT and TD kilnsare characterized by a rounded corner refractorydesign.

Thedesign adopts an innovative connection betweenupper and lower cylinders.This solution (Patent Pending) has been developedas a result of years of studies and mathematicalsimulations, in collaboration with a prominentGerman University and leading GermanInternational players in the refractory lining field.There are no pillars (hence the name “pillarless”) orhanging walls, featuring a “free flow” radial channelall around the shafts.

Furthermore the junction between the upper andlower sections of the kiln is made of bricks, with theevident advantage of having full control of therefractory material quality, thus increasing the lininglifetime and simplifying its maintenance.

«Pillarless» design of the Cim-RD kiln

The Lining

21

Refractory

Standard configuration F Siner tone

configuration

Mathematical simulation (CFD) of the shaft in combustion all over the limestone

Mathematical simulation (CFD) of the temperature into the shaft in combustion

22

23

Solid

Solid fuels:�Petcoke�Anthracite�Lignite�Coal�Saw dust...

Liq

uid

Liquid fuels:�LDO�MDO�HFO�Waste oils...

Gaseous�Natural gas

�Lean Gas such as:�COG�BF�Corex gas�Mixed gas...

By way of illustration, TSR kilns can be fired with:

SystemFiring

The

Nowadays, great importance is given to the abilityto use different fuels.The primary driving force for fuel selection is thecost, as it represents about 40-50% of the totalproduction cost of the quicklime.

Environmental regulations are the second majordriving force.

The third is product quality requirements.

Cimprogetti has also focused on the developmentof burner lances to give the best flame quality and safe working conditions.

24

Having always been sensitive to technicalinnovation and striving to add value to its plants,Cimprogetti has studied, designed and realized itsown control system, which is continuously updatedon the basis of the experience gained in the designand commissioning kilns worldwide.

Designed for industrial environments, where thesecurity of data and personnel is a primary issue,the control system manages all the problemsrelevant to the regulation, control and tracking ofdata and functions of plant operation while keepingits user friendly characteristics.

Last but not least, remote data transfer andanalysis of the kiln operation, alarm managementas well as on line scheduled maintenance support,are only but a few of the standard features of theCimrogetti control package.

Cimprogetti control system is the software of thelime experts.

The System

25

Control

From our headquarters or directly on site, ourspecialists are fully committed to support ourcustomers in all phases of a project...

be it a brand new installation,

or the modernization of existing units,

or simply to support plants operationalrequirements,

or training operators on all phases of kiln useand maintenance.

Assistance

26

Worldwide

Cimprogetti is your single source

supplier for

from the concept idea to feasibility

study, from the engineering design

and supply of equipment and

materials to turn-key plant realization.

Lime Technologies

27

Cim

prog

etti

s.p.

a. -

M-A

. Gre

llier

- 0

1.20

10

Cimprogetti S.p.A.Via Pasubio 5, ang. Via Einstein 24044 Dalmine (Italy)ph. +39 0354550 111 fax +39 0354550 335e-mail: inform@cimprogetti.com www.cimprogetti.com

Cap. soc. Euro 1.000.000 i.v. - c.f. e p. IVA 00221170160 - r.e.a. 119273S.p.A. a socio unico - soggetta a direz. e coord. di FMW Industrieanlagenbau GmbH (A)

A company

of the group

Lime Technologies

from A to Z

Since 1967