EP1235044A1 - Prekalzinationssystem eines Drehofens für die Zementherstellung - Google Patents

Prekalzinationssystem eines Drehofens für die Zementherstellung Download PDF

Info

Publication number
EP1235044A1
EP1235044A1 EP01301541A EP01301541A EP1235044A1 EP 1235044 A1 EP1235044 A1 EP 1235044A1 EP 01301541 A EP01301541 A EP 01301541A EP 01301541 A EP01301541 A EP 01301541A EP 1235044 A1 EP1235044 A1 EP 1235044A1
Authority
EP
European Patent Office
Prior art keywords
precalciner
oxygen
hot air
rotary kiln
air duct
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP01301541A
Other languages
English (en)
French (fr)
Inventor
Darius Ardeshir Wadia
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Priority to EP01301541A priority Critical patent/EP1235044A1/de
Publication of EP1235044A1 publication Critical patent/EP1235044A1/de
Withdrawn legal-status Critical Current

Links

Images

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
    • F27B7/00—Rotary-drum furnaces, i.e. horizontal or slightly inclined
    • F27B7/20—Details, accessories, or equipment peculiar to rotary-drum furnaces
    • F27B7/2016—Arrangements of preheating devices for the charge
    • F27B7/2025—Arrangements of preheating devices for the charge consisting of a single string of cyclones
    • F27B7/2033—Arrangements of preheating devices for the charge consisting of a single string of cyclones with means for precalcining the raw material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F23/00—Mixing according to the phases to be mixed, e.g. dispersing or emulsifying
    • B01F23/20—Mixing gases with liquids
    • B01F23/23—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids
    • B01F23/237—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids characterised by the physical or chemical properties of gases or vapours introduced in the liquid media
    • B01F23/2376—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids characterised by the physical or chemical properties of gases or vapours introduced in the liquid media characterised by the gas being introduced
    • B01F23/23761—Aerating, i.e. introducing oxygen containing gas in liquids
    • B01F23/237612—Oxygen
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F23/00—Mixing according to the phases to be mixed, e.g. dispersing or emulsifying
    • B01F23/30—Mixing gases with solids
    • B01F23/34—Mixing gases with solids by introducing gases in solid materials, e.g. in masses of powder or particles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F25/00—Flow mixers; Mixers for falling materials, e.g. solid particles
    • B01F25/30—Injector mixers
    • B01F25/31—Injector mixers in conduits or tubes through which the main component flows
    • B01F25/314—Injector mixers in conduits or tubes through which the main component flows wherein additional components are introduced at the circumference of the conduit
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F2101/00—Mixing characterised by the nature of the mixed materials or by the application field
    • B01F2101/501—Mixing combustion ingredients, e.g. gases, for burners or combustion chambers

Definitions

  • This invention relates to a precalciner rotary kiln system for cement manufacture.
  • An increase in temperature in the sintering zone of a rotary kiln may be obtained by use of oxygen enriched air preferably along with preheated combustion air.
  • Increase in flame temperature results in increased heat transfer by radiation in the sintering zone of a cement rotary kiln.
  • Stefan-Boltzmann Law cf "Efficient Use of Fuel” publication, His Majesty's Stationery Office (HMSO), London
  • the rate of heat transmission by radiation varies as the fourth power of the absolute temperature. Therefore, the higher the temperature difference between the hotter and cooler surfaces in the sintering zone of a rotary kiln, the greater is the heat transfer by radiation.
  • Literature references pertaining to use of oxygen enriched air in the sintering zone of a rotary kiln discuss pilot scale tests or short duration trials in larger capacity operating cement rotary kilns by dry or wet process route. These pilot scale trials are concerned with introduction of oxygen enriched air and fuel component through the kiln firing pipe into the sintering zone of a cement rotary kiln to increase the flame temperature and to obtain improved fuel efficiency and higher kiln outputs.
  • the primary air introduced through the firing pipe into the kiln constitutes only 10% of the combustion air requirement of the kiln (exclusive of the precalciner).
  • the scope for incorporation of oxygen through the kiln firing pipe would therefore be very restricted.
  • the path length of combustion air entering the kiln through the grate cooler at around 900°C is relatively short. This involves a steep gradient in temperature of the combustion air in the cooler transition zone. Introduction of oxygen in the kiln through this zone would involve difficulties in precise dosage control.
  • close control over flame shape and intensity is essential for maintaining a satisfactory protective clinker coating in the sintering zone to prolong refractory life in the sintering zone. This is very difficult to achieve.
  • An object of the invention is to provide a precalciner-rotary kiln system for cement manufacture which achieves accelerated combustion and increased production by introduction of oxygen in the precalciner (secondary furnace) where heat transfer is effected to raw material particles that are suspended in the hot gases.
  • Another object of the invention is to provide a precalciner rotary kiln system for cement manufacture which reduces power consumption of precalciner-cyclone preheater system by reducing the exit gas quantity leaving the precalciner-kiln system.
  • Another object of the invention is to provide a precalciner rotary kiln system for cement manufacture which is smooth and steady in operation.
  • Another object of the invention is to provide a precalciner rotary kiln system for cement manufacture which utilises surplus quantity of lower temperature air from the grate cooler (or other source) for instance to preheat cement raw meal.
  • a precalciner rotary kiln system for cement manufacture consisting of an oxygen source connected to the hot air duct leading to the precalciner of the precalciner rotary kiln system through a dosage unit.
  • 1 is a precalciner rotary kiln system consisting of a rotary kiln 2 whose firing pipe is marked 3.
  • the rotary kiln is fed by a four stage suspension cyclone preheater system 4 comprising a first stage of two cyclone preheaters 5 and 6 in parallel, a second stage of cyclone preheater 7, a third stage of cyclone preheater 8, a fourth stage of cyclone preheater 9 and a precalciner 10 connected to the cyclone preheaters 8 and 9.
  • 11 is an induced draft fan connected to the cyclone preheaters 5 and 6.
  • 12 is a grate cooler connected to the rotary kiln through a throat 13.
  • 15 is a low temperature hot air duct vent.
  • 16 is a hot air duct from the grate cooler to the precalciner.
  • 17 is a cyclone dust collector provided with the hot air duct.
  • 18 is a raw meal feed silo. 19 is the continuous pneumatic conveyor system feeding raw meal to the cyclone preheater system.
  • an oxygen source 20 connected to the hot air duct through a dosage unit 21 between the dust collector and the precalciner.
  • the dosage unit comprises an endless header pipe 22 provided around the hot air duct and connected to the oxygen source through an oxygen inlet line 23.
  • 24 is a support for the header pipe.
  • a plurality of nozzles 25 is connected to the header pipe and protrude into the hot air duct. The nozzles are staggered along the hot air duct tilted in the direction of flow of hot air through the hot air duct. Oxygen enters the hot air duct through the nozzles and mixes with hot air therein. Dust in the hot air passing through the hot air duct is trapped in the cyclone dust collector.
  • Residual dust entry into the nozzles is minimised by the tilted positioning of the nozzles in the direction of flow of the hot air.
  • the staggered positioning of the nozzles along the duct ensures better mixing of oxygen and hot air prior to entry into the precalciner.
  • the multistage suspension cyclone preheater system may be of a different configuration such as five or six stages or two or more strings of multi stage systems in parallel configuration with the precalciner connected to one string while the other strings handle kiln exit gases.
  • the temperature in the precalciner is required to be maintained below 900°C for achieving 90 to 95% decarbonation of cement raw meal in the precalciner prior to entry into the kiln.
  • Around 60 to 65% of total fuel to the kiln-precalciner system is fed to the precalciner.
  • oxygen enriched preheated combustion air By supply of oxygen enriched preheated combustion air to the precalciner, increased and accelerated combustion is achieved, along with a reduction in residence time and higher throughput for the precalciner, particularly when coal is used as a fuel. This is because of the favourably higher oxygen content and reduced volume of the incoming preheated combustion air which has a lower nitrogen content.
  • Optimum economy can be effected by use of 90% oxygen, for which capital and power cost is lower.
  • Introduction of oxygen into the precalciner is simple and far more precise as compared to introduction of oxygen into the kiln through the fuel firing pipe or by incorporation into the secondary stream from the cooler to the kiln. This is because of the lower combustion temperature in the precalciner (below 900°C), and a far more precise dosage control of oxygen.
  • overall fuel savings for the kiln and precalciner enable a reduction in total combustion air requirements from the grate cooler for both the kiln and precalciner.
  • the following comparative Table 1 gives a summarised indication of fuel efficiency, productive capability and other parameters for a precalciner-rotary kiln system with fuel consumption of 730 kcals/kg clinker with and without oxygen incorporation.
  • Data relating to the precalciner-rotary kiln system with oxygen incorporation are based on fuel distribution ratio of 40:60.
  • Data relating to the precalciner rotary kiln system without oxygen incorporation are based on established norms given in manufacturers' technical presentations and other literature sources.
  • kiln/precalciner distribution ratio of 40:60 has been indicated.
  • the objective is to achieve decarbonation of 90 to 95% in the precalciner before entry of raw meal into the kiln.
  • fuel efficiencies without and with oxygen incorporation are 730 and 703 kcals/kg clinker respectively, ie a net saving of 27 kcals/kg clinker with oxygen incorporation.
  • the split up combustion air composition without oxygen incorporation is 21% oxygen by volume, while that of the combustion air for the precalciner is 29% oxygen by volume.
  • the total combustion air stream for kiln and precalciner with oxygen incorporation has a higher oxygen content of 25% by volume. Because of the corresponding lower nitrogen content, exit gas volume vented from the preheater is reduced from 1.4 Nm 3 /kg clinker without oxygen to 1.25 Nm 3 /kg clinker with oxygen incorporation, ie a reduction of 0.15 Nm 3 /kg clinker. This reduction in exit gas volume enables a 12% increase in clinker production capacity based on utilisation of the reserve dimension capacity of the precalciner/cyclone preheater system. The above indicated fuel saving and increase in clinker production capacity are conservatively based.
  • a resultant higher precalciner combustion air temperature of over 900°C can be achieved with oxygen incorporation.
  • a lower temperature of 800°C has been indicated in Table I.
  • exit gas temperature would drop to below 280°C.
  • Table I a higher exit gas temperature of 300°C with oxygen incorporation has been indicated.
  • the hot combustion air coming from the grate cooler may be taken from an air/exit gas heat exchanger system located before the waste gas fan of the suspension cyclone preheater system 4. This would be relevant for a white cement plant where emerging hot clinker is commonly quenched in a water stream for obtaining a desired bluish tint.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Muffle Furnaces And Rotary Kilns (AREA)
  • Furnace Details (AREA)
EP01301541A 2001-02-21 2001-02-21 Prekalzinationssystem eines Drehofens für die Zementherstellung Withdrawn EP1235044A1 (de)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP01301541A EP1235044A1 (de) 2001-02-21 2001-02-21 Prekalzinationssystem eines Drehofens für die Zementherstellung

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP01301541A EP1235044A1 (de) 2001-02-21 2001-02-21 Prekalzinationssystem eines Drehofens für die Zementherstellung

Publications (1)

Publication Number Publication Date
EP1235044A1 true EP1235044A1 (de) 2002-08-28

Family

ID=8181729

Family Applications (1)

Application Number Title Priority Date Filing Date
EP01301541A Withdrawn EP1235044A1 (de) 2001-02-21 2001-02-21 Prekalzinationssystem eines Drehofens für die Zementherstellung

Country Status (1)

Country Link
EP (1) EP1235044A1 (de)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2005003665A2 (en) * 2003-07-04 2005-01-13 Holcim Ltd. Method and system for process gas entrainment and mixing in a kiln system
CN109353989A (zh) * 2018-09-27 2019-02-19 四川岷江雪盐化有限公司 一种氯酸钠生产低温余热回收和利用方法

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB713064A (en) * 1950-04-14 1954-08-04 Holmes & Co Ltd W C Improvements in method and apparatus for the oxidation of solutions and/or suspensions of oxidisable solids by means of oxygen-containing gases
US3913617A (en) * 1972-11-20 1975-10-21 Hoogovens Ijmuiden Bv Apparatus for mixing two gas flows
US4187071A (en) * 1975-03-10 1980-02-05 Klockner-Humboldt=Deutz Aktiengesellschaft Method for the treatment of finely grained material, particularly for the precalcining of cement
US4400138A (en) * 1981-10-19 1983-08-23 Baer William F Multiple jet eductor
US4913742A (en) * 1982-04-16 1990-04-03 Voest-Alpine Aktiengesellschaft Process of making cement clinker and apparatus for performing said process
WO1999006778A1 (en) * 1997-07-30 1999-02-11 Southdown, Inc. Oxygen enrichment of cement kiln system combustion

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB713064A (en) * 1950-04-14 1954-08-04 Holmes & Co Ltd W C Improvements in method and apparatus for the oxidation of solutions and/or suspensions of oxidisable solids by means of oxygen-containing gases
US3913617A (en) * 1972-11-20 1975-10-21 Hoogovens Ijmuiden Bv Apparatus for mixing two gas flows
US4187071A (en) * 1975-03-10 1980-02-05 Klockner-Humboldt=Deutz Aktiengesellschaft Method for the treatment of finely grained material, particularly for the precalcining of cement
US4400138A (en) * 1981-10-19 1983-08-23 Baer William F Multiple jet eductor
US4913742A (en) * 1982-04-16 1990-04-03 Voest-Alpine Aktiengesellschaft Process of making cement clinker and apparatus for performing said process
WO1999006778A1 (en) * 1997-07-30 1999-02-11 Southdown, Inc. Oxygen enrichment of cement kiln system combustion

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2005003665A2 (en) * 2003-07-04 2005-01-13 Holcim Ltd. Method and system for process gas entrainment and mixing in a kiln system
WO2005003665A3 (en) * 2003-07-04 2005-04-21 Holcim Ltd Method and system for process gas entrainment and mixing in a kiln system
CN109353989A (zh) * 2018-09-27 2019-02-19 四川岷江雪盐化有限公司 一种氯酸钠生产低温余热回收和利用方法

Similar Documents

Publication Publication Date Title
CN112105880B (zh) 具有特殊氧气添加的氧燃料熟料生产
CA3098598C (en) Oxyfuel clinker production without recirculation of the preheater exhaust gases
US4039277A (en) Apparatus for calcining powder materials
CN102112834B (zh) 在设备中制造水泥熟料的方法以及如此制造水泥熟料的设备
EP1037005B1 (de) Sauerstoffanreicherung von Gasen in einer Klinkerproduktionsanlage
CN102112833A (zh) 在设备中制造水泥熟料的方法以及如此制造水泥熟料的设备
KR890000861B1 (ko) 시멘트 클링커 제조방법
HUP0003051A2 (hu) Eljárás és berendezés cementklinker előállítására
KR910000710B1 (ko) 분말원료 소성장치
US4276020A (en) Method for heating powder material and apparatus for carrying out said method
CA1097501A (en) Method of burning granular or pulverulent raw material and kiln plant therefor
EP3738939A1 (de) Verfahren zum kalzinieren von rohmehl für die zementklinkerherstellung
EP0391463B1 (de) Reduktion der Stickstoffoxid-Emission aus einer Ofenanlage
US4366000A (en) Method and apparatus for preheating dry raw meal prior to introduction of the meal into a suspension cyclone preheater system supplying a rotary kiln
US3973980A (en) Process for the heat treatment of material in dust form
EP1235044A1 (de) Prekalzinationssystem eines Drehofens für die Zementherstellung
EP1017958B1 (de) Verbrennungs-sauerstoffanreicherung in zementofen-systemen
WO2021026713A1 (zh) 由在线型分解炉改造的可调节co2富集量水泥窑系统及其使用方法
US20230175778A1 (en) Installation for the thermal treatment of dispersible raw material, and method for operating such an installation
US4431453A (en) Process and apparatus for producing hydraulic cement
CN115380015A (zh) 用于生产水泥熟料的方法和装置
US4416697A (en) Method for preheating cement clinker raw materials
US4416696A (en) Method for heat treating cement clinker raw materials
CN117945676B (zh) 水泥熟料生产系统及水泥熟料生产方法
EP4303200A1 (de) Verfahren zum mindestens teilweisen kalzinieren eines rohmaterials in einem verfahren zum produzieren eines zementartigen materials

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE TR

AX Request for extension of the european patent

Free format text: AL;LT;LV;MK;RO;SI

AKX Designation fees paid

Designated state(s): AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE TR

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

18D Application deemed to be withdrawn

Effective date: 20020929