Bypass InteractionsChlorineSulphur

7/30/2019 Bypass InteractionsChlorineSulphur

http://slidepdf.com/reader/full/bypass-interactionschlorinesulphur 1/15

NEW REASONS FOR INSTALLING A CHLORIDE BY-PASS. INTERACTION BETWEENCHLORIDE AND SULPHUR.

By Ebbe Jøns, Søren Hundebøl and Kim Clausen – FLSmidth

Abstract

The growing use of alternative fuels and raw materials are increasing the input of chloride tomany kiln systems. Too high chloride is influencing economy in clinker production by causing

kiln stoppages, corrosion, and uneven clinker quality. The effects of chloride are stronglyinfluenced by the sulphur load in the kiln. This paper presents a modelling of the chloridecirculation in the kiln and how this is influenced by the sulphur load, deduced from simplethermodynamic considerations, and supported by statistical treatment of data collected frommore than 50 modern kiln systems.

A new reason for installing a by-pass is introduced: The use of the by-pass to counteract SO2

emissions caused by pyrite containing raw materials is documented.

Simple calculation rules are presented showing the basic differences in design of small (1-3%) and large (>10%) by-passes. Differences in chloride sensitivity between pre-heater andpre-calciner kilns are explained and illustrated. Finally some modern by-pass designs arepresented.

Introduction

Chlorine is one of the elements of most concern in cement production. There is hardly anyadvantage at all associated with the presence of chloride in raw materials or fuels used for cement production. One can ask where we possibly can benefit from chloride.

Calcium chloride finds use for production of low alkali clinker (Ref 1) and chlorides in the kilnsystem improve absorption of SO2 gas in the preheater, thus reducing the demand for secondary measures like hydrated lime addition (Ref 2). Both of these uses must becombined with a chloride by-pass to make them operational. A third reason for deliberateaddition of chloride to the kiln system is use of secondary fuels like bone meal. Cost savingsmust also in this case fully defend all drawbacks.

Involuntary presence of chloride in raw materials or fuels is all in all a costly matter for cementproducers, in increased fuel consumption, in kiln stops and in increased corrosion. Toaddress these issues, the paper first gives a brief review of the chemistry of chloride in the hotparts of the cement process, then the corrosion issues on the kiln shell and the riser pipes areshortly discussed, and finally the paper ends with an introduction to the effective preventivemeasure, a chloride by-pass.

The Chemistry of Chloride in Cement Kilns

Chloride can enter the cement process from raw materials and fuels. Often it is present in thecrystal lattice of clay minerals or present as organic bound chloride in fuels. It can also enter when secondary fuels and raw materials in the form of various industrial by-products areused.

The chlorine of organic bound compounds will be released as gaseous hydrochloric acid inthe first place. In the calciner and lower preheater stages the HCl will be absorbed by freelime:

CaO + 2 HCl = CaCl2 + H2O

In the burning zone, there is no reactive free CaO suspended in the flame, and HCl from kilnfuel will therefore go directly to the preheater and be converted to CaCl2 there.

978-1-4244-2081-0/08/$25.00 © 2008 IEEE



Regardless of the chemical nature of chloride/chlorine when/where it enters the kiln system itwill soon be present as part of the liquid phase in the charge in the transition and burningzone of the kiln. It is likely that all the salts in the hot meal on their way to the burning zoneare collected in one phase that gradually exchanges calcium with alkalis from the other phases (the main source of potassium is the clay component).

It is generally accepted that the liquid phase in clinker consists of two immiscible phases: Theclinker melt and the sulphate melt. Chloride is present in the sulphate melt together withsulphate, potassium, sodium and calcium. See figure 1.

Figure 1: Phase diagram for the sulphate-melt in clinker with the three primary precipitationsfield for Anhydrite, Langbeinite and Apthitalite. Chloride in clinker is at higher temperaturedissolved in the sulphate melt.

Chloride evaporates from the sulphate melt as the clinker passes the burning zone.Depending on conditions (time, temperature and content of sulphate melt) between 95 andalmost 100 % of the chloride evaporates. Chloride evaporates as potassium chloride KCl(g)or sodium chloride NaCl(g). Molten K2SO4 and mixtures of K2SO4 and CaSO4 are quite stableat high temperatures (at least if the kiln is operated with a sufficient excess of air). A reactionwith water vapour that produces HCl(g) is very limited at the burning zone temperature.

The gaseous chloride will move with the gas flow back to the preheater or calciner, where itwill condense to molten salt on cold raw meal. The chloride may take several turns back tothe burning zone. A small flow gets out of the circulation retained in the sulphate phase of theclinker and reaches the cooler.

In a few cases the mineral chloro-ellestadite ( (CaO)9(SiO2)3(SO3)3CaCl2 ) has been identifiedin clinker, and this is a compound with a certain stability at high temperatures. It may be

responsible for carrying some Cl out with the clinker. Phosphate impurities are thought tostabilize the ellestadite. (Ref 3,4)

It is the reactive molecule HCl(g) that is responsible for the initiation of kiln shell corrosion(Ref 6) and it is the condensation of alkali chlorides that participate in the sulphidation of thehot central tube in the lowest cyclone.

Kiln shell corrosion products are often FeS2 and Fe3O4, why SO2 could be expected to be theculprit, but there is no significant statistical correlation between sulphur input and kiln shellcorrosion. There is, however, a good correlation between chloride input and shell corrosion.(Ref 5)



A bypass is a well-known method of reducing the internal circulation. The bypass is taking outa proportion of the gas flow coming out of the rotary kiln in order to open a valve for thechloride to come out.

Mathematical description

The general picture of the circulation is this:

Figure 2: Simplified circulation pattern for chloride in the kiln used for making mass balancefor chloride.

If the input flow with the raw materials and the fuel is called F, the flow into the rotary kiln withthe hot meal is called H, the valve (or bypass) fraction is called b, and the fraction of thechloride evaporated in the burning zone e, we get the mass balance INPUT = OUTPUTthrough valve and clinker, respectively:

F = H e b + H (1-e)

Strictly speaking, in this equation F is the sum of input with raw materials, calciner fuel, andkiln fuel times (1-b).

From this equation the hot meal flow could be predicted, if we knew the values e and b:

H / F = 1 / (e b + (1-e) )

The figure e is generally close to 1. In the same kiln it may easily vary from 0.95 to 0.99,depending on the burning zone conditions.

A closed kiln system without a physical bypass has always some valve through the preheater.So in this case b and (1-e) are both small numbers. The figure b is probably fairly constant,but (1-e) is highly variable. The calculation of H/F is division of 1 with a small and unstable

sum, why it is a figure with high uncertainty.

If on the other hand the kiln system is equipped with a considerable bypass, the equationreduces to

H / F = 1 / b (for b >> 0)

A bypass reduces the circulation, and the hot meal chloride content tends to become morestable and relatively independent on the burning zone conditions.

The fraction of the chloride input coming out with the clinker is:

Feed&fuel clinker

valve

fuel



C / F = (1-e) / ( e b + (1-e) )

For small bypass values the clinker content depends strongly on the evaporation factor. For large bypass values, the figure approaches zero.

The size of the required by-pass can be determined either from a process stability point of view (maximum allowed chloride content in hot meal) or from a product quality point of view(maximum permissible chloride content in clinker). This is i llustrated in the figure below wherethe required by-pass is calculated to keep a maximum hot meal content of 1.0% (LOI – free

basis) and a maximum content of 0.04 % Chloride in the clinker.

By-pass size as function of Chloride feed rate

Max hot meal Cl = 1.0 % / Max clinker Cl = 0.04%

0.00

0.01

0.10

1.00

0.001 0.01 0.1 1

Input of chloride as kg/100kg clinker

R e q u i r e d b y - p a s s a s % o

f g a s f l o w

i n k i l n

0.995

0.99

0.97

0.95

0.9

Evaporation factor

Figure 3: Figure illustrating the difference between small and large by pass. Effectiveness of small by pass is very dependent on the evaporation factor.

It is clearly seen how important the evaporation factor is for design of a small by-pass whilethe simple rule

% by-pass = chloride input on clinker basis / critical Cl content in hot meal applies for larger by-passes, unless clinker quality aspects (particularly visible at lowevaporation factors) makes a larger by-pass necessary.

Thermodynamic discussion of factors controlling the evaporation

It is possible to deduce an expression for the evaporation factor, which is the ratio of (amountevaporated to the gas phase) / (amount retained in clinker) = e/ (1-e).

A crude approach is to consider the gas phase of the burning zone, normally called the flame,as a well-stirred system with a characteristic temperature, and the clinker leaving the burning

zone with a small content of sulphate melt is at least approaching thermal and chemicalequilibrium with the gas phase.

The most important chemical reaction in the burning zone is of course the reaction of belitewith free lime to form alite. This is another example of an equilibrium (free CaO = 0) that isapproached, but never reached completely.

If chemical equilibrium was obtained, the free energy of KCl in the gas phase must be equalto the free energy of KCl in the sulphate phase, where this salt is dissolved:

H1 – T S1 + RT ln pKCl/po = H2 – T S2 + RT ln xKCl



Here the enthalpy H and the entropy S have been introduced. T is the temperature (K). p o isthe standard pressure (1 atm).

From this it is directly derived, that the evaporation factor ought to be proportional to the molar flow of gas out of the burning zone Mgas, and inversely proportional to the molar flow of sulphate out of the burning zone with the clinker MSO3. But the most important is thetemperature:

e/ (1-e) = c * Mgas / MSO3 * po/p exp( - ǻH/RT)

The ǻH in the equation is the heat of vaporisation for KCl. At 1673 K this figure is 37800cal/mol. A temperature increase of 100

ogives an evaporation that is 2-3 times higher.

The main difference between a suspension preheater kiln and a calciner kiln is the specificgas flow, which typically is 0.4 times lower in the calciner kiln. This should mean that SP kilnshave higher evaporation factors than calciner kilns, if anything else was the same. The kilnsof the various systems (ILC, SLC, SLC-S, SLC-D) have more or less the same specific firingrate.

Kilns with high sulphur inputs and high sulphur content of the clinker should have lower evaporation of chloride than kilns with low sulphur inputs.

The barometric pressure p has an influence. Mountain plants should have higher evaporationthan plants at sea level.

Statistical data

The first plot shows the clinker content of Cl as a function of the total input.

Chloride input & output

0

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0 0.02 0.04 0.06 0.08 0.1 0.12

Cl (feed+fuel)

C l c l i n k e r

SP

calc

byp

Figure 4: Relationship between chloride input and chloride in clinker for different kiln systems(SP kilns, calciner kilns, and kilns with bypass). SP kilns are characterized with very low clinker chloride.

There are several examples of high chloride contents in clinker from calciner kilns, whereasthere are no really high values of clinker chloride from suspension preheater kilns in the FLS



database. The most plausible interpretation of the plot is that (1-e) is much lower in an SP kilnthan in a calciner kiln. It should be mentioned that 20-30 years ago the clinker was onlyanalyzed for chloride in very few cases. In lack of clinker chloride data we may look at the hotmeal to get an idea of the internal circulation.

The ratio of the chloride flow in the hot meal H (kg Cl/ton clinker) to the total chloride input F(kg Cl/ton clinker) is most directly demonstrating the evaporation factor (and the effect of abypass).

Chloride circulation

0

0.5

1

1.5

2

2.5

0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.1

Cl (feed+fuel)

C l h o t m e a l

SP

calc

byp

H/F = 50

H/F = 10

Figure 5: Chloride input versus chloride content in hot meal (LOI free basis). The tendency isthat SP kilns have higher evaporation factors. (High H/F)

The graph of figure 5 presents measured values of H as function of F. Data from 80 kilns

have been entered. Most values fall within the interval 10 < H/F < 50. As predicted by thetheory, the ratio is indeed unpredictable. The high scattering is of course a result of widelydifferent burning zone temperatures, and different sulphate contents.

The kilns with large bypasses are concentrated in the corner. Kilns with small bypasses arestill under influence of the burning zone conditions.

If calciner kilns and SP kilns had the same temperature, the evaporation should be higher inthe SP kiln than in the calciner kiln, as the gas volume from the latter is much smaller, andless KCl should be carried away. This statement may be true. We should, however, expectthe modern calciner kilns to be operated with a much higher thermal load, and they areprobably on the average somewhat hotter than the SP kilns in the burning zone. So the twoshotgun patterns for SP and calciner kilns fall more or less over the same area. There is atendency that only SP kilns fall outside the range H/F > 50.

The high scorers in the diagram represent kilns with raw materials of very poor burnability.

If the inverse ratio F/H is plotted against %SO3 of the clinker, it is perhaps better seen thathigh sulphate contents pull chloride out.



Cl evaporation

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0 0.5 1 1.5 2 2.5 3

SO3 clinker

C l ( f e e d ) / C l ( h o t m e

a l )

SP

calc

y = 0.015+0.03 x

r^2 = 0.51

Figure 6: Illustration of the effect of sulphate melt on evaporation of chloride. The higher thesulphate content in clinker, the lower the evaporation factor for chloride.

For calciner kilns we get b + (1-e) = 0.015 + 0.03 %SO3. (r 2

= 0.5)

This correlation is poor, but cannot be expected to be better due to variation in burning zonetemperatures. Data from kilns on mineralized clinker have not been entered.

Upgrading projects that preserve the kiln type (e.g replacing a planetary cooler with a moderngrate cooler) will generally mean increased thermal load on the kiln and consequently higher chloride circulation.

Conversion of SP kilns to calciner kilns will give lower chloride circulation, due to the muchlower specific gas flow from the burning zone. A very convincing demonstration of this isshown in the table.

Mode SO3 Cl K2O Na2O

SLC-D 1,71 0,82 2,75 0,12

SP 3,49 1,27 3,49 0,14

Hot meal flows kg/(100kg clinker)

Figure 7: Example of the effect of gas-solid ratio on chloride circulation.

What is the acceptable chloride content in the hot meal?

It has long been known that high chloride contents are acceptable, if the sulphate is low, andvice versa. The data from the 80 kilns are presented in figure 8:



Lower cyclone

0

0.5

1

1.5

2

2.5

3

3.5

0 1 2 3 4 5 6 7 8 9 10

SO3 hot meal

C l h o t m e a l

SP

calc

byp

Figure 8: Hot meal composition in operating kilns. The higher values of chloride and SO3 are predominantly from SP kilns.

All the kilns were kept in operation. Some of them required very frequent air-blasting of thelowermost cyclone, but nevertheless it can be seen from figure 2 that practical operation ispossible if the chloride and sulphate point is below the line from zero SO 3 and 2 kg Cl/100 kgclinker to zero Cl and 5 kg SO3/100 kg clinker.

The severity of cyclone blockages seems to increase with an index of this kind:

Cl /2 + SO3 /5

An interesting question is now, if it is an advantage or a disadvantage to put more sulphur into

the kiln (e.g. finding another fuel), given a specified chlorine input? Your immediate advice isprobably: Do not put more sulphur into the kiln! It may be true, that the increased sulphatecontent of the clinker will carry more chloride out, but the sulphate content of the hot meal willalso go up, and allow less chloride in the hot meal. It requires considerable knowledge toanswer the question correctly.

The formation of coatings in the riser pipe below the point where raw meal is introduced in thekiln gas flow is another problem related to circulating compounds. The severity is most likelybetter related to figures such as g Cl and g SO3 per Nm

3kiln gas. The temperature level plays

an important role.

The statistical data support the view that SP-kilns can take 30 to 40 % more chloride in the(LOI-free) hot meal than calciner kilns for same operational stability.

It has been shown that kilns are able to operate safely at higher chloride concentrations in thehot meal if they blow cold filter dust into the back end of the kiln. (Ref 9,11)

Distribution of chlorides in the preheater

The chlorides that were evaporated in the rotary kiln will usually be condensed again in theriser pipe or calciner on the added cold powder. The very fine particle fractions will absorbmore than the coarse fractions. As the fine particles have lower separation efficiency in acyclone than the coarse particles, a fraction of the condensed chlorides will not be sent back



to the kiln by the cyclone, but will go up into the preheater. A typical pattern will develop(figure 9 presenting %Cl profiles from three plants).

Preheater chloride

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

feed st 1 st 2 st 3 st 4

% C l

SP

ILC

SLC-D

Fig. 9. Chloride content (%) in raw meal flows of four-stage pre-heaters.

Modern ILC plants are often designed with a two-compartment calciner. The purpose is to runthe lower section of the calciner with high temperature (e.g. 1100

oC) in order to burn

petroleum coke or another difficult fuel and at the same time reduce the NOx emission. It mayfor these plants be demonstrated that a considerable amount of the alkali chloride enteringthe hot zone will remain gaseous or be evaporated. The chloride will get a higher probabilityof going up into the upper stages of the pre-heater. In these plants a considerable circulation

of chloride between the hot calciner section and the second and third lowermost cyclonesmay develop. This is illustrated in figure10. The relatively high flows of chloride can in somecases be an advantage.



Figure 10: Chloride circulation in an ILC kiln with a hot calciner section. The thickness of thelines is proportional to chloride flow. The different colors represent gaseous, liquid and solid alkali chloride (Ref 6).

The importance of chloride for the SO2 emission from the pre-heater

The main source of SO2 coming out of the preheater is pyrite FeS2 which is decomposed toFeS + S in the first place. The S burns quickly to SO2. A fraction of this sulphur dioxide will beabsorbed in the preheater. The FeS is somewhat more stable and will reach the hotter stagesof the preheater where there is an abundance of CaO, and the SO2 will nearly always beabsorbed completely.

The re-absorption of SO2 in the upper stages of a preheater has been shown to be verydependent on the chloride content of the raw meal. Very convincing trials were made in thepilot 2 installation of test centre Dania in year 2000. The emission could be suppressed from375 ppm down to 150 ppm or even 100 ppm by adding chloride salt in an amountcorresponding to 0.14 or 0.20% Cl in the raw meal, respectively.



Dania SO2 absorption test Oct. 2000

0

100

200

300

400

500

600

14.00 15.00 16.00 17.00 18.00 19.00 20.00 21.00 22.00 23.00

time

p p m S

O 2

- k g / h

SO2

kg/h

saltmix 1

Ca(OH)2

saltmix 2 saltmix 2

Figure 11: Graph showing relationship between chloride content in the preheater feed and SO2 emission out of the stack. (Ref 2)

Firing chlorine-containing waste into the kiln, calciner or Hot Disc may thus be beneficial inthe way, that some chloride will go up in the pre-heater section and facilitate the re-absorptionof SO2. A calciner operated with a hot zone may also give this advantage.

There is surprisingly a risk, that the S circulation will be quite unstable in the following way.Suppose at an instant that the Cl concentration is high in the pre-heater. This gives highabsorption of SO2, and the flow of sulphate into the kiln will increase. After a while anincreased level of sulphate will arrive in the burning zone. This will make the evaporation of chloride lower, and more chloride will leave the kiln system dissolved in the sulphate phase of the clinker. The flow of chloride into the preheater will now decrease, and consequently, more

SO2 will be lost from the preheater. The flow of sulphate into the kiln is now decreasing, andthe cycle may start all over.

The problem will be further aggravated, if the oscillations bring the values of (Cl, SO3) in thehot meal or kiln gas above the critical level, so that coatings start to build up in the cyclone,kiln riser or the upper part of the rotary kiln. A considerable inventory of sulphate may becollected, and later suddenly released (for instance when the preheater is cleaned).

The method of making the chloride a stable emission-workhorse is the following. The kilnshould be equipped with a bypass. The bypass dust is collected in a silo and mixed well. Afraction of it is metered to the kiln feed. The chloride is then promoting the re-absorption of SO2 in the preheater, will go down in the rotary kiln and finally escape it through the bypass. Itis important that the bypass has a size, so that the e value for Cl has no big influence on thefeed to hot meal ratio for chloride F/H. It is further very important to operate the kiln with highexcess of air, and the raw mix must have good burnability.

Powder characteristics of by-pass dust

When the hot kiln gases enter the calciner and preheater they will gradually be cooled downby mixing with colder material. That will lead to precipitation of the volatiles in the gas phaseon the surface of the colder powder by heterogeneous nucleation, impairing the flow behavior of the preheater charge. Most of the chlorides will for that reason be retained with the raw



meal and only a limited over presentation of chlorides is present in the preheater dust.(Typical filter dust chloride concentrations are 0.2-0.5% Cl.)

It is different in a by-pass where the gas is cooled by mixing with clean cold gas. Under suchconditions the chlorides will precipitate by homogeneous nucleation in the gas phase asvirtually pure alkali chlorides. It is for that reason possible to recover very pure salts from theby-pass by appropriate selective dust recovery. One should be aware of the bad flowcharacteristics of these dusts.

Chloride Salts

Raw meal

Preheater Dust By-pass dust

Figure 12: The fundamental difference between preheater dust and by pass dust. By passdust has a clear bimodal PSD.

Particle size distribution for typical by-pass dust

0

0.5

1

1.5

2

2.5

3

3.5

4

0.100 1.000 10.000 100.000 1000.000

Particle size in µm

V o l u m e % o

f f r a c t i o n

Figure 13: By pass dust sample. Particles below 4µm are almost pure alkali chlorides.

It has long been practiced to return the coarse fractions precipitated in the front sections of anelectrostatic precipitator to the kiln, while the fine fractions rich in chloride from the backsections are discarded (ref. 12). Small flows of bypass dust may be disposed of in the cementmill, provided that the quality requirements of the cement can be maintained.

By-pass design

A by-pass consists of

• Quench chamber to bring the temperature down below fusion point for chloride salts

• One or more dust collectors

• Device for further gas-cooling depending on dust collector

Many different designs are available on the market. (Ref 9,10)

The functioning of a quench chamber is shown in the CFD picture below. The better themixing in the quench chamber, the less air is required having impact on filter and fan sizing.



Fig 14: Simulation of temperature distribution after quench chamber with central pipe.

The simplest by-pass design is shown below and is relevant for small gas flows. The coolingis made by mixing with air in two steps, the first one for bringing the gas below the fusionpoint of the salts, the second step for adjusting the temperature required for the filter. Theshown dust collector is a jet-pulse filter. It can be combined with an up-stream cyclone for removal of coarse (low-chloride) dust. Such design is very low investment and is applicablefor temporary use or for low gas flows.

Fig 15: Simple by-pass flow sheet for small gas volumes

For higher gas flows it is economically feasible to invest in further gas cooling with water inorder to reduce the gas flow (in actual m3/h) through filter and fan. As shown below. This isnormally done with a cooling tower. It is also in this case possible to apply an up-streamcyclone for removal of coarse dust.



Fig 16: By pass flow sheet for larger gas volumes

In some plants, installation of a by-pass is complicated by high SO2 concentrations in the kilninlet. This can be solved either by leading the quenched gas back to the preheater or by

exchanging the cooling tower with a gas suspension absorber (GSA). Another (almostforgotten) solution is to use the still hot gas (after cleaning in an ESP) in the raw mill. In somecases it is possible to reduce SO2 circulation by changes in kiln operation (Increased oxygenin kiln or improved raw meal burn-ability).

Conclusions

The effectiveness of small by-pass depends strongly on the chloride evaporation factor.

From thermodynamic considerations it is deduced that the chloride evaporation factor depends on three parameters

•

Burning zone temperature• Kiln gas to charge ratio

• Sulphur concentration in the charge

The thermodynamic considerations are made plausible by statistical treatment of plant data.Plant data further support the view that ease of kiln operation is a function of hot mealcomposition and follows Cl/2 + SO3/5. This is true if one class of kiln systems (e.g. ILC kilns)is considered.

Chloride by-pass has secondary benefits apart from operational improvements:

• Prevent (or at least reduce the rate of) kiln shell corrosion

• Gives opportunity for using chloride containing alternative fuel

• Gives opportunity for improved SO2 absorption in the preheater

Due to the special two-component character of by-pass dust, chloride by-pass can bedesigned to deliver high concentration-low quantity end products.

By-pass dust from small by-pass can in many cases be utilized (disposed of) in the cementdepartment.



References:

1. Holden, E.R., Reduction of Alkalies in Portland Cement, Industrial and EngineeringChemistry, vol. 42. p. 337, 1950.

2. WO 02/28512 (Chloride patent) L.S.Jensen ,E.S. Jons. FLS 20023. Chlorellestadite in the preheater system of cement kilns as an indicator of HCl formation.

Simon Jegou Saint-Jean, E. Joens, N. Lundgaard, S. Hansen. Cement and ConcreteResearch 35 (2005) 431-437

4. Decreasing chloride level in cement rotary kiln atmosphere by sorption intohydroxyapatite structure. Pavel Martauz, J. Strigáz, M. Jamnicky. ZKG International 5(2007) 75-87

5. Investigation into shell corrosion of rotary cement kilns. E.Jons, M.J.L. Ostergaard.ZKGInternational. 2 (1999) 68-79

6. Volatile circulation in Kiln and Preheater. Internal FLS memo. Kim Clausen,20077. Experimentelle Untersuchung und Modellierung des Verhaltens von Spurenelementen im

Zementklinkerbrennprozess. Forschungsinstitut der Zementindustrie, AIFForschungsvorhaben, 2004

8. Formation of kiln riser duct coating. T. Enkegaard. Internal FLS memo, 19939. Ein neues Chlorid by-pass-System mit stabiler Ofenführung und Staubverwertung. K.

Sutou, H.Harada, N.Ueno. ZKG International 3 (2001) 121-12810. Practical capability of different Cl by-pass systems H. Schöffmann, M.Weichinger. VDZ

Congress 2002, 246-25111. EP 1296905 (Dust injection patent) S. Hundebol FLS 200112. GB 1145827 (Dust f ractionation patent) T. Heilmann FLS 1965.

Bypass InteractionsChlorineSulphur

Documents

Transcript of Bypass InteractionsChlorineSulphur