GB1563918A - Cement calcining apparatus - Google Patents
Cement calcining apparatus Download PDFInfo
- Publication number
- GB1563918A GB1563918A GB5113376A GB5113376A GB1563918A GB 1563918 A GB1563918 A GB 1563918A GB 5113376 A GB5113376 A GB 5113376A GB 5113376 A GB5113376 A GB 5113376A GB 1563918 A GB1563918 A GB 1563918A
- Authority
- GB
- United Kingdom
- Prior art keywords
- coal
- fuel
- burner
- furnace
- suspension
- 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.)
- Expired
Links
- 238000001354 calcination Methods 0.000 title claims description 31
- 239000004568 cement Substances 0.000 title claims description 17
- 239000003245 coal Substances 0.000 claims description 50
- 239000000446 fuel Substances 0.000 claims description 47
- 239000000725 suspension Substances 0.000 claims description 32
- 239000000463 material Substances 0.000 claims description 28
- 238000002485 combustion reaction Methods 0.000 claims description 21
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 claims description 8
- 238000005422 blasting Methods 0.000 claims description 6
- 239000000295 fuel oil Substances 0.000 claims description 6
- 229910002092 carbon dioxide Inorganic materials 0.000 claims description 4
- 239000001569 carbon dioxide Substances 0.000 claims description 4
- 239000012530 fluid Substances 0.000 claims description 4
- 238000004868 gas analysis Methods 0.000 claims description 4
- 239000000571 coke Substances 0.000 claims description 3
- 239000003921 oil Substances 0.000 claims description 3
- 238000000151 deposition Methods 0.000 claims description 2
- 239000002994 raw material Substances 0.000 claims description 2
- 238000007670 refining Methods 0.000 claims description 2
- 230000001105 regulatory effect Effects 0.000 claims description 2
- 239000010802 sludge Substances 0.000 claims description 2
- 239000004449 solid propellant Substances 0.000 claims description 2
- 230000001276 controlling effect Effects 0.000 claims 1
- 239000007789 gas Substances 0.000 description 8
- JTJMJGYZQZDUJJ-UHFFFAOYSA-N phencyclidine Chemical class C1CCCCN1C1(C=2C=CC=CC=2)CCCCC1 JTJMJGYZQZDUJJ-UHFFFAOYSA-N 0.000 description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- 235000008733 Citrus aurantifolia Nutrition 0.000 description 1
- 235000011941 Tilia x europaea Nutrition 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 238000007664 blowing Methods 0.000 description 1
- 239000000567 combustion gas Substances 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000008187 granular material Substances 0.000 description 1
- 239000004571 lime Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
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
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B7/00—Hydraulic cements
- C04B7/36—Manufacture of hydraulic cements in general
- C04B7/43—Heat treatment, e.g. precalcining, burning, melting; Cooling
- C04B7/434—Preheating with addition of fuel, e.g. calcining
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Ceramic Engineering (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Structural Engineering (AREA)
- Organic Chemistry (AREA)
- Curing Cements, Concrete, And Artificial Stone (AREA)
- Furnace Details (AREA)
- Feeding, Discharge, Calcimining, Fusing, And Gas-Generation Devices (AREA)
- Crucibles And Fluidized-Bed Furnaces (AREA)
- Muffle Furnaces And Rotary Kilns (AREA)
Description
(54) CEMENT CALCINING APPARATUS
(71) We, ONODA CEMENT CO. LTD., of 6276 Oaza Onoda, Onoda-shi, Yamaguchiken, Japan, a Company organised and existing under of the Laws of Japan, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to cement calcining apparatus.
Calcining furnaces are known in which the material to be calcined is carried in suspension n hot combustion gas to be efficiently preheated by heat exchange with the gas so that the material granules are well dried and heated.
In the cement industry, cement calcining apparatus with a suspension preheater has
been generally utilized in which material is
carried in suspension in hot gases drawn from
the kiln exhaust for such preheating.
Lately cement calcining apparatus has come to be put in practice in which a calcining device is provided in the preheater section to simultaneously effect combustion of fuel and
calcining of the material with the use of heavy oil as fuel.
Calcining in such a device has the advan
tages that the material and fuel are in a mixed
state and combustion and heat conduction
are performed in the shortest possible time,
and the material is effectively proclaimed for
most effective subsequent processing, e.g. in
cement production the material reaches the
kiln entrance at a lime standard of 85-90%.
It is known that the combustion of pul verizedcoal is such that firstly volatile fractions
are released and burnt and then the carbon is
burnt. In the past, the speed of blowing a
suspension of pulverized coal into a furnace
was generally at least 25-35 m/s for avoiding
low-back of flame, however, (1) when pulver
ized coal suspension is blown with this speed
into a calcining furnace, combustion may be
incomplete because of insufficient generation
of volatile fraction in the furnace;
(2) part of the pulverized coal may be
driven in a state of incomplete combustion
from the furnace into the material supply
cyclones and these tend to make secondary combustion, this causes clogging of cyclones;;
(3) as incompletely burnt pulverized coal may enter mixed with the material into the kiln, temperature distribution in the kiln varies, tending to produce caking.
For these reasons pulverized coal has not hitherto been conveneintly used as fuel for calcining cement material in this type of device. Further, combustion control using pulverized coal is more difficult as compared with fluid fuels (heavy oil or gas), because of the following.
(1) The combustion of the carbon in pulverized coal takes longer than with heavy oil or gas, thus it is necessary to provide more effective combustion in the calcining device.
(2) When starting up or with the plant under little or no load, it is necessary to lessen the amount of pulverized coal, however, for the sake of security, flow in the coal blast tube has to be maintained at 25-35 mlst As a result, the density of pulverized coal becomes thin and combustion in the calcining device becomes very low. For this reason, for the combustion of pulverized coal in the furnace of such system it has been proposed to provide a plurality of burner units, changes in load or output being met by some one or more of the burner units being turned on or off individually for control, while if using heavy oil or gas load control is more simple as it can be carried out not only by varying the amount of fuel blown in suspension.
The object of the present invention is to provide a calcining device in which pulverised fuels can be used while providing for a wide range of load control, enabling efficient combustion in a stable manner while avoiding clogging of cyclones due to secondary combustion, so as to obtain effectively calcined material ready for subsequent processing.
According to the invention there is provided calcining apparatus including a furnace into which material to be calcined is fed, a source for operatively providing a flow of pulverised fuel in suspension, a constant-feed burner in said furnace, constant-feed mechanism supplied with fuel from said flowin use and operable to feed it in suspension at a predetermined constant rate to said burner, and a load-control burner in said furnace having connection to said source independently of the constant-feed mechanism, the supply of fuel to the latter burner being selectively adjustable to control the total amount of pulverised fuel supplied to the furnace to meet variations in load.
Other features and objects of the invention will be better understood from the detailed description of a typical embodiment illustrated in the accompanying drawings, in which: Figure 1 is a diagrammatic front view of a cement plant using pulverised coal as fuel,
Fig. 2 is a longitudinal sectional view of a cement calcining furnace of said plant, and
Fig. 3 is a graph of gas analysis related to the speed or flow of pulverised coal in suspension in the calcining furnace.
In Fig. 2, numeral 4 generally designates a calcining furnace. 13, 14 are hot air entrances from a heat exchanger. 15 are raw material chutes for feeding in material to be calcined.
22 is a coal feed tube leading directly to a load control burner 24. 26 is a coal hopper with a constant rate mechanical feeder 27 for feeding coal by way of a coal blast tube 30 to a constant-feed burner 32. 23, 31 are flexible hoses for permitting adjustment of the burner nozzle positions to avoid damage of the furnace wall caused by contact of coal flame thereto or to avoid depositing of ash thereon.
In the cement apparatus including said calcining furnace 4 shown in Fig. 1, material supplied from a feeder 10 passes through cyclone 9, cyclone 8 and cyclone7 successively, is pre-heated by heat exchange with hot gas, and then enters thefurnace4. For combustion, hot air is supplied through entrances 13, 14 from a heat exchanger 3 at the exhaust from rotary kiln 2. A fuel source comprises a feeder 16 from which coal is fed to be pulverized in a coal crusher 17 and led via a bucket elevator 18 to enter a grading separator 19 in granulated form. Air is supplied by a fan 20 to convey the pulverised fuel flow in suspension by way of a flow separator 21 where it is divided into two streams. One for load control burner 24 and the other for constant-feed burner 32.The former stream passes directly through coal feed tube 22 to be blown in suspension in to the furnace 4 by the load control burner 24. The latter stream is collected in a cyclone 25 and stored in a hopper 26. Coal is drawn from hopper 26 by the constant rate feeder 27 and is conveyed with a fan 28 utilizing exhaust gas from cyclone 25 to enter in suspension through the constant-feed burner 32 into the furnace 4.
The material calcined in the furnace 4 is advanced to a mixing chamber 5 wherein the material is mixed with exhaust gas from main 1nln 2. The material thus further calcined is p-cd to cylone 6. Then the material is stwlied to the main rotary kiln 2.
When cement material is calcined with pulverised coal fuel in suspension from the constant-feed burner even at a minimum rate of about 20% of the coal fuel supplied by both burners at this maximum load, it is found that a good result can be obtained, thus adjustment to suit the load of the plant can be widely changed by regulating only the fuel supplied to the load control burner. Division of the coal for constant-feed blasting from that for load control is controlled by selective adjustment of the flow separator 21 independently of the constant feed mechanism associated with burner 32, the suspension of fuel for the latter being provided separately from the suspension formed at the fuel source by fan 20.
The coal blasting tubes- 24, 32 of the burners adjustments to the furnace may be made wide to slow the speed of flow of the suspension and to allow time for the generation of volatile fractions in the calcining furnace to promote the full combustion of the coal in the calcining furnace. This is illustrated in
Fig. 3. By slowing the speed of the coal fuel suspension (shown in the graph as "blasting speed") to 8-10 m/s, it shows in gas analysis 8-12% increase in carbon dioxide (CO2) in the furnace. By providing the supply of fuel to burner 32 at a predetermined rate above the minimum needed for stability of combustion in furnace 4 the independently from that supplied to the load control burner 24 which can be adjusted to meet variations in load, stable combustion may be maintained even at times of low load when burner 24 may be shut down completely.
In the above description reference is made only to pulverized coal. However, it is to be understood that other solid fuels having the same property is as pulverized coal, for example, F.O.C. (fluid oil cokes) by-produced as sludge in refining heavy oil may also be used.
WHAT WE CLAIM IS 1. Calcining apparatus including a furnace into which material to be calcined is fed, a source for operatively providing a flow of pulverised fuel in suspension, a constantfeed burner in said furnace, constant-feed mechanism supplied with fuel from said flow in use and operable to feed it in suspension at a predetermined constant rate to said burner, and a load-control burner in said furnace having connection to said source independently of the constant-feed mechanism, the supply of fuel to the latter burner being selectively adjustable to control the total amount of pulverised fuel supplied to the furnace to meet variations in load.
2. Apparatus as in Claim 1 including a separator in said flow in which the fuel supply to the constant feed mechanism is operatively separated from the supply to the load-control burner.
**WARNING** end of DESC field may overlap start of CLMS **.
Claims (8)
- **WARNING** start of CLMS field may overlap end of DESC **.load-control burner in said furnace having connection to said source independently of the constant-feed mechanism, the supply of fuel to the latter burner being selectively adjustable to control the total amount of pulverised fuel supplied to the furnace to meet variations in load.Other features and objects of the invention will be better understood from the detailed description of a typical embodiment illustrated in the accompanying drawings, in which: Figure 1 is a diagrammatic front view of a cement plant using pulverised coal as fuel, Fig. 2 is a longitudinal sectional view of a cement calcining furnace of said plant, and Fig. 3 is a graph of gas analysis related to the speed or flow of pulverised coal in suspension in the calcining furnace.In Fig. 2, numeral 4 generally designates a calcining furnace. 13, 14 are hot air entrances from a heat exchanger. 15 are raw material chutes for feeding in material to be calcined.22 is a coal feed tube leading directly to a load control burner 24. 26 is a coal hopper with a constant rate mechanical feeder 27 for feeding coal by way of a coal blast tube 30 to a constant-feed burner 32. 23, 31 are flexible hoses for permitting adjustment of the burner nozzle positions to avoid damage of the furnace wall caused by contact of coal flame thereto or to avoid depositing of ash thereon.In the cement apparatus including said calcining furnace 4 shown in Fig. 1, material supplied from a feeder 10 passes through cyclone 9, cyclone 8 and cyclone7 successively, is pre-heated by heat exchange with hot gas, and then enters thefurnace4. For combustion, hot air is supplied through entrances 13, 14 from a heat exchanger 3 at the exhaust from rotary kiln 2. A fuel source comprises a feeder 16 from which coal is fed to be pulverized in a coal crusher 17 and led via a bucket elevator 18 to enter a grading separator 19 in granulated form. Air is supplied by a fan 20 to convey the pulverised fuel flow in suspension by way of a flow separator 21 where it is divided into two streams. One for load control burner 24 and the other for constant-feed burner 32.The former stream passes directly through coal feed tube 22 to be blown in suspension in to the furnace 4 by the load control burner 24. The latter stream is collected in a cyclone 25 and stored in a hopper 26. Coal is drawn from hopper 26 by the constant rate feeder 27 and is conveyed with a fan 28 utilizing exhaust gas from cyclone 25 to enter in suspension through the constant-feed burner 32 into the furnace 4.The material calcined in the furnace 4 is advanced to a mixing chamber 5 wherein the material is mixed with exhaust gas from main 1nln 2. The material thus further calcined is p-cd to cylone 6. Then the material is stwlied to the main rotary kiln 2.When cement material is calcined with pulverised coal fuel in suspension from the constant-feed burner even at a minimum rate of about 20% of the coal fuel supplied by both burners at this maximum load, it is found that a good result can be obtained, thus adjustment to suit the load of the plant can be widely changed by regulating only the fuel supplied to the load control burner. Division of the coal for constant-feed blasting from that for load control is controlled by selective adjustment of the flow separator 21 independently of the constant feed mechanism associated with burner 32, the suspension of fuel for the latter being provided separately from the suspension formed at the fuel source by fan 20.The coal blasting tubes- 24, 32 of the burners adjustments to the furnace may be made wide to slow the speed of flow of the suspension and to allow time for the generation of volatile fractions in the calcining furnace to promote the full combustion of the coal in the calcining furnace. This is illustrated in Fig. 3. By slowing the speed of the coal fuel suspension (shown in the graph as "blasting speed") to 8-10 m/s, it shows in gas analysis 8-12% increase in carbon dioxide (CO2) in the furnace. By providing the supply of fuel to burner 32 at a predetermined rate above the minimum needed for stability of combustion in furnace 4 the independently from that supplied to the load control burner 24 which can be adjusted to meet variations in load, stable combustion may be maintained even at times of low load when burner 24 may be shut down completely.In the above description reference is made only to pulverized coal. However, it is to be understood that other solid fuels having the same property is as pulverized coal, for example, F.O.C. (fluid oil cokes) by-produced as sludge in refining heavy oil may also be used.WHAT WE CLAIM IS 1. Calcining apparatus including a furnace into which material to be calcined is fed, a source for operatively providing a flow of pulverised fuel in suspension, a constantfeed burner in said furnace, constant-feed mechanism supplied with fuel from said flow in use and operable to feed it in suspension at a predetermined constant rate to said burner, and a load-control burner in said furnace having connection to said source independently of the constant-feed mechanism, the supply of fuel to the latter burner being selectively adjustable to control the total amount of pulverised fuel supplied to the furnace to meet variations in load.
- 2. Apparatus as in Claim 1 including a separator in said flow in which the fuel supply to the constant feed mechanism is operatively separated from the supply to the load-control burner.
- 3. Apparatus as in Claim 2 whereinadjustment of the fuel supply to the load control burner is effected by controlling the division of said flow by the separator.
- 4. Apparatus as in Claim 1, 2 or 3 wherein the constant-feed mechanism comprises a cyclone, storage hopper and constant rate mechanical feeder, together with a fan for forming a suspension of the fuel independently of the suspension provided by said source in use.
- 5. Apparatus as in anyone of the preceding claims adapted to use pulverised coal as said fuel.
- 6. Apparatus as in any one of Claims 1 to 4 adapted to use fluid oil cokes as said fuel.
- 7. Calcining apparatus substantially as herein described with reference to and as shown in the accompanying drawings.
- 8. A cement plant including calcining apparatus according to any one of the preceding claims.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2469476A JPS52108423A (en) | 1976-03-09 | 1976-03-09 | Apparatus for baking cement by using minute powdery coal |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB1563918A true GB1563918A (en) | 1980-04-02 |
Family
ID=12145265
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB5113376A Expired GB1563918A (en) | 1976-03-09 | 1976-12-06 | Cement calcining apparatus |
Country Status (5)
| Country | Link |
|---|---|
| JP (1) | JPS52108423A (en) |
| AU (1) | AU507643B2 (en) |
| BR (1) | BR7608727A (en) |
| CA (1) | CA1079065A (en) |
| GB (1) | GB1563918A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0313871A2 (en) * | 1987-10-30 | 1989-05-03 | Krupp Polysius Ag | Process and device for the thermal treatment of fines |
| EP0526770A2 (en) * | 1991-07-13 | 1993-02-10 | Klöckner-Humboldt-Deutz Aktiengesellschaft | Thermic treatment installation for raw fines |
| CN112408823A (en) * | 2019-08-20 | 2021-02-26 | 中国科学院工程热物理研究所 | Fuel supply system and method for industrial kiln equipment and industrial kiln equipment |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4263856A (en) * | 1979-02-08 | 1981-04-28 | Combustion Engineering, Inc. | Providing supplemental pulverized coal for load regain |
| JPH02134240U (en) * | 1989-04-17 | 1990-11-07 | ||
| JP2018118861A (en) * | 2017-01-23 | 2018-08-02 | 三菱マテリアル株式会社 | Method for producing cement |
-
1976
- 1976-03-09 JP JP2469476A patent/JPS52108423A/en active Granted
- 1976-12-06 GB GB5113376A patent/GB1563918A/en not_active Expired
- 1976-12-21 CA CA268,388A patent/CA1079065A/en not_active Expired
- 1976-12-24 AU AU20921/76A patent/AU507643B2/en not_active Expired
- 1976-12-28 BR BR7608727A patent/BR7608727A/en unknown
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0313871A2 (en) * | 1987-10-30 | 1989-05-03 | Krupp Polysius Ag | Process and device for the thermal treatment of fines |
| EP0313871A3 (en) * | 1987-10-30 | 1990-04-11 | Krupp Polysius Ag | Process and device for the thermal treatment of fines |
| EP0526770A2 (en) * | 1991-07-13 | 1993-02-10 | Klöckner-Humboldt-Deutz Aktiengesellschaft | Thermic treatment installation for raw fines |
| EP0526770A3 (en) * | 1991-07-13 | 1993-06-23 | Kloeckner-Humboldt-Deutz Aktiengesellschaft | Thermic treatment installation for raw fines |
| CN112408823A (en) * | 2019-08-20 | 2021-02-26 | 中国科学院工程热物理研究所 | Fuel supply system and method for industrial kiln equipment and industrial kiln equipment |
| CN112408823B (en) * | 2019-08-20 | 2023-06-27 | 中国科学院工程热物理研究所 | Fuel supply system and method for industrial kiln equipment and industrial kiln equipment |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS52108423A (en) | 1977-09-10 |
| CA1079065A (en) | 1980-06-10 |
| AU507643B2 (en) | 1980-02-21 |
| BR7608727A (en) | 1977-10-25 |
| AU2092176A (en) | 1978-06-29 |
| JPS5522429B2 (en) | 1980-06-17 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PS | Patent sealed | ||
| PCNP | Patent ceased through non-payment of renewal fee |