Dry process kiln systems - .kiln, SF Cross-Bar™ clinker cooler and Duoflex kiln burner Main features KILN SYSTEMS. Six standard Dry-process kiln system

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  • Highly reliable

    Low emission levels

    Efficient energy utilisation

    Dry process kiln systems

  • 2 Dry process kiln systems

    F.L.Smidth offers a range of six standarddry-process kiln systems, each with itsunique advantages depending upon theparticular application. In this way we areable to provide the industry with the mostsuitable kiln system configuration for anygiven set of conditions and requirements.

    F.L.Smidth has supplied over 2500 rotarykiln systems and more than 3500 clinkercoolers. This experience, coupled with thelatest advances in pyroprocessing systemdesign, makes our technology the logicalchoice for both new installations and mod-ernisation of existing cement making facilities.

    In modern cement plants, raw meal is pre-heated to calcination temperature in a mul-ti-stage cyclone preheater and most of thecalcination process takes place in a separate-ly fired calciner. The remaining calcinationand clinkerization process takes place in ashort length-to-diameter rotary kiln withoutinternals.

    Preference is commonly given to the coolingof clinker in the SF Cross-Bar cooler inwhich the two main functions, conveyingand cooling of clinker, are completely sepa-rated. The introduction of stationary air dis-tribution plates with self-regulatingmechanical flow regulators (MFR) has revo-lutionized cooler operation.

    This brochure describes each of the six kilnsystem configurations in detail and presentsgeneral guidelines for their selectiondepending upon capacity requirements andwhether the system is new or an upgradeof an existing installation. System compo-nents other than cyclones and calciners aredealt with in separate brochures that describetheir mechanical and operational features.

    Highly reliable systems for any production level

    A wide range of calciner systems tosuit specific require-ments

    Highly efficient lowpressure cyclones

    Effective emissioncontrol technology

    Optimized fuel andpower consumption

    Suitable for wastefuels

    Compact, space-savingpreheater designs

    Matching state-of-the-art technologiesfor clinkerization,cooling and firing:ROTAX-2 two-supportkiln, SF Cross-Barclinker cooler andDuoflex kiln burner

    Main features

    KI

    LN

    S

    YS

    TE

    MS

  • Six standard Dry-process kiln systemconfigurations

    SP: Suspension Preheater kiln

    ILC: In-Line Calciner

    SLC: Separate Line Calciner

    ILC-E: In-Line Calciner using Excess air

    SLC-D: Separate Line Calciner Downdraft

    SLC-I: Separate Line Calciner with In-line Calciner

  • 4 Dry process kiln systems

    Special advantages For small capacities

    the economical solution. Very low specific power consumption. Simple operation

    well suited for manual control. Accepts higher input of chlorides than

    precalcining systems with tertiary air duct(without bypass).

    SP: Suspension Preheater kiln

    Features Normal capacity range: 700-2800 tpd. Ratio of firing in riser duct: 0-15%. Bypass of kiln gas: 0-30%. Planetary cooler can be employed.

    5-stage SP kiln systemand SF Cross-Barcooler Typical temperatures inthe system are indicatedtogether with the neg-ative pressure in theexhaust gas exit basedon a system designedfor minimum overallpressure drop. This typeof kiln system can beconverted to the SLCprecalcining system byadding an extra calcin-ing string. If no futurecapacity increase is tobe considered, a plane-tary cooler may beconsidered.

    material

    gas

    fuel

    1. Raw meal feed

    2. Exhaust gas

    3. Kiln gas by-pass, if any

    4. Clinker

    5. Kiln burner

    6. Riser duct firing, if any

    7. Cooler excess air

  • Dry process kiln systems 5

    Special advantages Most economical solution for small and

    medium capacities. Low specific power consumption. Easy operation due to high excess air

    percentage in kiln. Low coating tendency in kiln inlet

    and riser duct. Long kiln lining life due to stable kiln

    coating. Less sensitive to chlorides and sulphur

    than precalcining systems with tertiary airduct (without bypass).

    Smaller kiln dimensions than SP system.

    ILC-E: In-Line Calciner using Excess air

    Features Normal capacity range: 800-3500 tpd. Ratio of firing in calciner: 10-25%. Bypass of kiln gas: 0-25%. Calcination at kiln inlet: 50-70% (com-

    pared to 30-40% for SP operation). Planetary cooler can be employed.

    material

    gas

    fuel

    1. Raw meal feed

    2. Exhaust gas

    3. Kiln gas by-pass, if any

    4. Clinker

    5. Kiln burner

    6. Calciner burners

    7. Cooler excess air

    ILC-E kiln system withfive-stage preheaterand SF Cross-BarcoolerTypical temperatures inthe system are indicat-ed, together with thenegative pressure in theexhaust gas exit, basedon a system designedfor minimum overallpressure drop. If nofuture capacity increaseis to be considered, aplanetary cooler maybe considered.

  • 6 Dry process kiln systems

    Special advantages High material and gas retention time in

    calciner due to its large volume and moderate swirl.

    Regulation range of up to 60% bypass of kiln gas using ILC-I version.

    Well suited for low-grade fuels. Long refractory life due to low thermal

    kiln load and stable kiln coating. Lowest NOx emission among traditional

    calciner kiln systems.

    ILC: In-Line Calciner

    Features Normal capacity range: 1500-5000 tpd,

    with multiple strings > 10,000 tpd. Ratio of firing in calciner: 55-65%. Normal bypass of kiln gas: 0-30%. Maximum bypass of kiln gas:

    0-100% using ILC-I version. Built-in low-NOx capabilities. Calcination at kiln inlet: 90-95%.

    ILC kiln system with five-stage preheater and SF Cross-Bar cooler Typical temperatures in thesystem are indicated,together with the negativepressure in the exhaust gasexit, based on a systemdesigned for minimum over-all pressure drop. Whendesigned for bypassing 30% or more of the kiln gases,the layout of the system willbe slightly different, as thetertiary air duct is connectedto the kiln riser duct at apoint below the calciner.This system is called the ILC-Icalciner system.

    material

    gas

    fuel

    1. Raw meal feed

    2. Exhaust gas

    3. Kiln gas by-pass, if any

    4. Clinker

    5. Kiln burner

    6. Calciner burners

    7. Tertiary air duct

    8. Tertiary air duct damper

    9. Cooler excess air

  • Dry process kiln systems 7

    Special advantages High material and gas retention times in

    the calciner/ combustion chamber whosedimensions are minimal since the kilngases do not pass through it.

    Very well suited for all fuel types, espe-cially low-volatile fuels, as the combustionin the calciner takes place in hot atmos-pheric air and the combustion tempera-ture in the calciner can be controlledindependently of the temperature of thecalcined material fed to the kiln.

    Low NOx operation is possible. Smallest possible tower dimensions, as

    the calciner can be installed separatelyfrom the cyclone tower.

    Especially well suited for retrofits of existing SP or ILC preheaters due to very short down time.

    SLC-D: Separate Line Calciner Downdraft

    Features Normal capacity range: 1500-5000 tpd,

    with multiple strings > 10,000 tpd. Firing in calciner: 55-60%. Bypass of kiln gas: 0-60%. Maximum bypass regulation range: 30%. Calcination at kiln inlet: 90-95%.

    SLC-D kiln system with five-stage preheater and SF Cross-Bar coolerTypical temperatures in thesystem are indicated,together with the negativepressure in the exhaust gasexit, based on a systemdesigned for minimumoverall pressure drop. Forproduction capacitiesexceeding approximately5000 tpd, the system isequipped with two or morepreheater strings, this alsobeing the case if a particu-larly low preheater tower isrequired.

    material

    gas

    fuel

    1. Raw meal feed

    2. Exhaust gas

    3. Kiln gas by-pass, if any

    4. Clinker

    5. Kiln burner

    6. Calciner burners

    7. Tertiary air duct

    8. Tertiary air duct damper

    9. Cooler excess air

    10.Raw meal dividing gate

  • Special advantages High material and gas retention times in the

    calciner whose dimensions are minimalsince the kiln gases do not pass through it.

    Very well suited for all fuel types, evenlow-volatile fuels, as the combustion inthe calciner takes place in hot atmosphericair, and (as an option) the combustiontemperature in the calciner can be con-trolled independently of the temperatureof the calcined material fed to the kiln.

    Long refractory life due to low thermalkiln load and stable kiln coating.

    Independent and accurate draft controlfor kiln and calciner strings by adjustingspeed of individual fans.

    No damper in tertiary air duct. Production down to 40% of capacity

    using kiln string only. Production down to 20% of capacity for

    three-string version.

    SLC: Separate Line Calciner

    material

    gas

    fuel

    1. Raw meal feed

    2. Exhaust gas

    3. Kiln gas by-pass, if any

    4. Clinker

    5. Kiln burner

    6. Calciner burners

    7. Tertiary air duct

    8. Cooler excess air

    9. Raw meal dividing gate

    10.Raw meal change-over gate

    SLC kiln system with SFCross-Bar cooler and five-stage preheater in the kilnand the calciner strings Typical temperatures in thesystem are indicated, togetherwith the negative pressurein the exhaust gas exits,based on a system designedfor minimum overall pressuredrop. The system offers thepossibility of controlling thetemperature level inside thecalciner, as part of the rawmeal from the second-low-est cyclone stage in the cal-ciner s