CA1133249A - Process and installation for precalcinating powderous or granular substances - Google Patents
Process and installation for precalcinating powderous or granular substancesInfo
- Publication number
- CA1133249A CA1133249A CA360,312A CA360312A CA1133249A CA 1133249 A CA1133249 A CA 1133249A CA 360312 A CA360312 A CA 360312A CA 1133249 A CA1133249 A CA 1133249A
- Authority
- CA
- Canada
- Prior art keywords
- cyclone
- kiln
- junction
- fumes
- installation
- 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
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
- B04—CENTRIFUGAL APPARATUS OR MACHINES FOR CARRYING-OUT PHYSICAL OR CHEMICAL PROCESSES
- B04C—APPARATUS USING FREE VORTEX FLOW, e.g. CYCLONES
- B04C5/00—Apparatus in which the axial direction of the vortex is reversed
- B04C5/24—Multiple arrangement thereof
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B04—CENTRIFUGAL APPARATUS OR MACHINES FOR CARRYING-OUT PHYSICAL OR CHEMICAL PROCESSES
- B04C—APPARATUS USING FREE VORTEX FLOW, e.g. CYCLONES
- B04C5/00—Apparatus in which the axial direction of the vortex is reversed
- B04C5/24—Multiple arrangement thereof
- B04C5/30—Recirculation constructions in or with cyclones which accomplish a partial recirculation of the medium, e.g. by means of conduits
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B04—CENTRIFUGAL APPARATUS OR MACHINES FOR CARRYING-OUT PHYSICAL OR CHEMICAL PROCESSES
- B04C—APPARATUS USING FREE VORTEX FLOW, e.g. CYCLONES
- B04C9/00—Combinations with other devices, e.g. fans, expansion chambers, diffusors, water locks
-
- 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
- C04B7/432—Preheating without addition of fuel
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Ceramic Engineering (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Materials Engineering (AREA)
- Structural Engineering (AREA)
- Organic Chemistry (AREA)
- Furnace Details (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
This invention is related to an installation for calcinating powderous or granular matter, such as cement making raw material comprising a preheater constituted by at least one column of cyclones wherein a flow of the material to be treated is circulated, a rotary kiln fed with said material flow, and a cooler for cooling the product treated in said kiln, said installation further comprising a fumes outlet flue coaxial to said kiln for evacuating fumes from said kiln, said flue being constructed so as to constitute an extension of said kiln and to open into at least one junction cyclone which is connected to the last stage of said reheater by a gas outlet conduit.
This invention is related to an installation for calcinating powderous or granular matter, such as cement making raw material comprising a preheater constituted by at least one column of cyclones wherein a flow of the material to be treated is circulated, a rotary kiln fed with said material flow, and a cooler for cooling the product treated in said kiln, said installation further comprising a fumes outlet flue coaxial to said kiln for evacuating fumes from said kiln, said flue being constructed so as to constitute an extension of said kiln and to open into at least one junction cyclone which is connected to the last stage of said reheater by a gas outlet conduit.
Description
~i~32~9 PROCESS AND INSTALLATION FOR PRECALCINATING POWDEROUS
OR GRANULAR SUBSTANCES
~."
The present invention is related to a process and an COE~c~ jn~
installation for ~aleul~lng powderous or granular substances, such as raw material for making cement, which calcination is carried out prior to the burning (or firing) of said materials ;n a furnace or kiln.
Calcinating installations of this kind are larca~y known, which comprise a preheater constituted by one or more columns, a rotary kiln and a cooler adapted to cool the product treated in said kiln. Each column may be provided individually with a pre-calcinator adapted to calcinate entirely or partially the rawmaterial introduced into the kiln.
In the known installations the gases issuing from the top of the rotary kiln are directed toward the lower portion of the preheater by means of a conduit which deviates the flow path of the fumes issuing from the kiln from a substantially horizontal trajectory to a substantially vertical trajectory, which deviation occurs within the fumes chamber.
Furthermore, it is known that when a fuel having a sulphur , content higher than 1% is used in a rotary kiln of this type, consi-derable deposits will occur at the junction of the kiln and the exchanger. These deposits result inprogressively reducing the cross-sectional flow area of the gases issuing from the kiln, which entails a considerable decrease of the output of the installation.
These deposits are due partially to the abrupt change of the flow direction of the gases issuing from the kiln, which 1~332~9 hcl r, ~e b~=~eff`en~ brings about areas of turbulence or so-ca11ed "dead areas"
prone to lead to decantation and depositing of solid particles.
Two French patent applications filed by the Applicant (n 74-11 196 and n 74-30 711) disclose methods aimed at eliminating such deposits.
It is an object of the present invention to transform the transition zone between the kiln and the preheater so as to cp~
confer on such zone an ~pti~us aerohydrodynamic profile. With this object in view, the invention relates to an installation comprising a preheater constituted by at least one column of cyclones wherein a flow of matrial to be treated is circulated, a rotary kiln fed with said flow of material and a cooler for cooling the product treated in said kiln, and further comprising a flue for evacuating the fumes issuing from the kiln, said flue being coaxial to said kiln and pro-longating the same, while opening into at least one junction cyclone,which cyclone is connected to the last stage of the preheater by a gas outlet conduit.
In a preferred embodiment of the invention the said gas outlet conduit has an angled configuration. Thus the gases issuing from the k;ln are directed through a flue coaxial to said kiln, and are directed without any modification of the flow direction toward one or two cyclones from which they issue to flow then toward the preheater. The modification ofthe flow direction of the gases issuing from the kiln ;s thus not achieved in a fumes chamber but in a cyclone and is consequently achieved under optimum aerohydrodynamic conditions. Any 1~33'~9 matter issuing from any of the stages of the preheater is injected into the flue connecting the kiln to the junction cyclone with a view to decreasing the temperatureof the fumes issuing from the ki1n and to limiting the risk of formation of deposits in said flue.
S Depending on the flow rate for which the installation is designed, one or two junction cyclones may be provided.
The invention will be descrihed hereinafter in a more detailed manner with reference to the appended drawings which are given by way of illustration but not of limitation.
Fig. 1 of the drawing is a schematical view of an installation according to the ;nvention, wherein air issuing possibly from the cooler is injected into the lowermost end of the junction cyclone, while burners are provided within the latter.
Fig.2 shows a detail of the installation according to Fig. 1.
Fjg.3 is a horizontal sectional view of a modification of the installation shown in Fig. 1, comprising two junction cyclones.
Fig.4 schematically shows another modification of the installation according to the invention, wherein the matter passing through the junction cyclone is taken up by an air flow issuing possibly from the cooler, and is then directed toward the precalcinator.
In a first embodiment of the invention, as shown in Fig.1 the calcinating installation comprises a conventional rotary kiln 10 wherein the raw material is treated, or fired at a temperature of about 1500C by means of a counter-current flame,this kiln being 11332~9 connected according to a feature of the present invention, through a cyclone 12 to the last cyclone IV of a four-stage column forming a preheater 13. The matter issuing from the penul-timate cyclone III of said preheater 13 is directed toward a hor-izontal fumes outlet flue 14 connecting kiln 10 to junction cyclone 12 through a conduit 20. Said conduit 20 preferably is adapted to direct the matter in the form of a curtain or screen into the fumes issuing from the kiln, where said matter is taken up by said fumes and circulating in cyclone 12 with a view to removing suspended matter from the fumes, prior to being taken up again by gases issuing from a cooler by way of a conduit 21 into a lower conduit 19 of junction c.yclone 12, said matter then passing through an angled or cranked flue 22 toward the last cyclone stage IV of the preheater, whereafter said matter passes from said cyclone IV toward the kiln through conduit 23. Fuel is injected by burners 24 provided at the base of cyclone 12 so as to provide the energy required for total or partial decarbonation. The coolant carried by conduit 21 may be air.
Fig. 2 is a section view of a detail of the installation of Fig. 1, shown on a larger scale.
As clearly shown in Fig. 2 the conduit 20 through which flows the matter issuing from the penultimate cyclone III which discharges into flue 14 through a flattened injection nozzle, while conduit 23 discharges into flue 14 by way of outlet 25, which flue constitutes an extension of the ferrule 26 of kiln 10.
According to an aspect of the present invention two junction cyclones suchas cyclone12, connected to flue14 ofkiln 10,may beprovided.
11332~9 Such modification is shown in Fig. 3 which is a horizontal sectional view taken along line III-III in Fig. 2.
As shown, two junction cyclones 12a and 12b assoc;ated to conduits 23a and 23b connected to the preheater are provided in this embodiment.
Fig. 4 shows another embodiment of the present invention wherein the fumes issuing from kiln 10 pass through flue 14 coaxial to said kiln and enter the junction cyclone 12 according to the invention. The matter issuing from cyclone IV of the preheater is introduced through a conduit 25 and fiue 14 into said junction cyclone 12i said matter is then introduced at 19 into a cooling gas flow issuing possibly through 21 from the cooler, whereafter said matterenters a precalcinator 27 comprising burners 28 where it undergoespartial or total decarbonation prior to being separated ; 15 from the gases in cyclone IV' and prior to being finally introduced through conduit 23' into the rotary kiln.
The gases issuing at 30 and 30' from cyclone IV and IV' are introduced into a cyclone III prior to flowing through pairs of cyclones II and I. The two circuits carrying the gases issuing from the kiln as well as the cooling gas flow from conduit 21 may be balanced by means of an adjustable valve 32 provided in the conduit outlet 30 of cyclone IV.
The invention is not limited to the embodiments shown and described herein-above, numerous modifications and variants ; 25 may be envisaged by those skilled in the art without departing there-fore from the scope of the invention as defined in the appended claims.
OR GRANULAR SUBSTANCES
~."
The present invention is related to a process and an COE~c~ jn~
installation for ~aleul~lng powderous or granular substances, such as raw material for making cement, which calcination is carried out prior to the burning (or firing) of said materials ;n a furnace or kiln.
Calcinating installations of this kind are larca~y known, which comprise a preheater constituted by one or more columns, a rotary kiln and a cooler adapted to cool the product treated in said kiln. Each column may be provided individually with a pre-calcinator adapted to calcinate entirely or partially the rawmaterial introduced into the kiln.
In the known installations the gases issuing from the top of the rotary kiln are directed toward the lower portion of the preheater by means of a conduit which deviates the flow path of the fumes issuing from the kiln from a substantially horizontal trajectory to a substantially vertical trajectory, which deviation occurs within the fumes chamber.
Furthermore, it is known that when a fuel having a sulphur , content higher than 1% is used in a rotary kiln of this type, consi-derable deposits will occur at the junction of the kiln and the exchanger. These deposits result inprogressively reducing the cross-sectional flow area of the gases issuing from the kiln, which entails a considerable decrease of the output of the installation.
These deposits are due partially to the abrupt change of the flow direction of the gases issuing from the kiln, which 1~332~9 hcl r, ~e b~=~eff`en~ brings about areas of turbulence or so-ca11ed "dead areas"
prone to lead to decantation and depositing of solid particles.
Two French patent applications filed by the Applicant (n 74-11 196 and n 74-30 711) disclose methods aimed at eliminating such deposits.
It is an object of the present invention to transform the transition zone between the kiln and the preheater so as to cp~
confer on such zone an ~pti~us aerohydrodynamic profile. With this object in view, the invention relates to an installation comprising a preheater constituted by at least one column of cyclones wherein a flow of matrial to be treated is circulated, a rotary kiln fed with said flow of material and a cooler for cooling the product treated in said kiln, and further comprising a flue for evacuating the fumes issuing from the kiln, said flue being coaxial to said kiln and pro-longating the same, while opening into at least one junction cyclone,which cyclone is connected to the last stage of the preheater by a gas outlet conduit.
In a preferred embodiment of the invention the said gas outlet conduit has an angled configuration. Thus the gases issuing from the k;ln are directed through a flue coaxial to said kiln, and are directed without any modification of the flow direction toward one or two cyclones from which they issue to flow then toward the preheater. The modification ofthe flow direction of the gases issuing from the kiln ;s thus not achieved in a fumes chamber but in a cyclone and is consequently achieved under optimum aerohydrodynamic conditions. Any 1~33'~9 matter issuing from any of the stages of the preheater is injected into the flue connecting the kiln to the junction cyclone with a view to decreasing the temperatureof the fumes issuing from the ki1n and to limiting the risk of formation of deposits in said flue.
S Depending on the flow rate for which the installation is designed, one or two junction cyclones may be provided.
The invention will be descrihed hereinafter in a more detailed manner with reference to the appended drawings which are given by way of illustration but not of limitation.
Fig. 1 of the drawing is a schematical view of an installation according to the ;nvention, wherein air issuing possibly from the cooler is injected into the lowermost end of the junction cyclone, while burners are provided within the latter.
Fig.2 shows a detail of the installation according to Fig. 1.
Fjg.3 is a horizontal sectional view of a modification of the installation shown in Fig. 1, comprising two junction cyclones.
Fig.4 schematically shows another modification of the installation according to the invention, wherein the matter passing through the junction cyclone is taken up by an air flow issuing possibly from the cooler, and is then directed toward the precalcinator.
In a first embodiment of the invention, as shown in Fig.1 the calcinating installation comprises a conventional rotary kiln 10 wherein the raw material is treated, or fired at a temperature of about 1500C by means of a counter-current flame,this kiln being 11332~9 connected according to a feature of the present invention, through a cyclone 12 to the last cyclone IV of a four-stage column forming a preheater 13. The matter issuing from the penul-timate cyclone III of said preheater 13 is directed toward a hor-izontal fumes outlet flue 14 connecting kiln 10 to junction cyclone 12 through a conduit 20. Said conduit 20 preferably is adapted to direct the matter in the form of a curtain or screen into the fumes issuing from the kiln, where said matter is taken up by said fumes and circulating in cyclone 12 with a view to removing suspended matter from the fumes, prior to being taken up again by gases issuing from a cooler by way of a conduit 21 into a lower conduit 19 of junction c.yclone 12, said matter then passing through an angled or cranked flue 22 toward the last cyclone stage IV of the preheater, whereafter said matter passes from said cyclone IV toward the kiln through conduit 23. Fuel is injected by burners 24 provided at the base of cyclone 12 so as to provide the energy required for total or partial decarbonation. The coolant carried by conduit 21 may be air.
Fig. 2 is a section view of a detail of the installation of Fig. 1, shown on a larger scale.
As clearly shown in Fig. 2 the conduit 20 through which flows the matter issuing from the penultimate cyclone III which discharges into flue 14 through a flattened injection nozzle, while conduit 23 discharges into flue 14 by way of outlet 25, which flue constitutes an extension of the ferrule 26 of kiln 10.
According to an aspect of the present invention two junction cyclones suchas cyclone12, connected to flue14 ofkiln 10,may beprovided.
11332~9 Such modification is shown in Fig. 3 which is a horizontal sectional view taken along line III-III in Fig. 2.
As shown, two junction cyclones 12a and 12b assoc;ated to conduits 23a and 23b connected to the preheater are provided in this embodiment.
Fig. 4 shows another embodiment of the present invention wherein the fumes issuing from kiln 10 pass through flue 14 coaxial to said kiln and enter the junction cyclone 12 according to the invention. The matter issuing from cyclone IV of the preheater is introduced through a conduit 25 and fiue 14 into said junction cyclone 12i said matter is then introduced at 19 into a cooling gas flow issuing possibly through 21 from the cooler, whereafter said matterenters a precalcinator 27 comprising burners 28 where it undergoespartial or total decarbonation prior to being separated ; 15 from the gases in cyclone IV' and prior to being finally introduced through conduit 23' into the rotary kiln.
The gases issuing at 30 and 30' from cyclone IV and IV' are introduced into a cyclone III prior to flowing through pairs of cyclones II and I. The two circuits carrying the gases issuing from the kiln as well as the cooling gas flow from conduit 21 may be balanced by means of an adjustable valve 32 provided in the conduit outlet 30 of cyclone IV.
The invention is not limited to the embodiments shown and described herein-above, numerous modifications and variants ; 25 may be envisaged by those skilled in the art without departing there-fore from the scope of the invention as defined in the appended claims.
Claims (7)
1. An installation for calcinating powderous or granular matter, such as cement making raw material, comprising a preheater constituted by at least one column of cyclones wherein a flow of the material to be treated is circulated, a rotary kiln fed with said material flow, and a cooler for cooling the product treated in said kiln, said installation further comprising a fumes outlet flue coaxial to said kiln for evacuating fumes from said kiln, said flue being constructed so as to constitute an extension of said kiln and to open into at least one junction cyclone which is connected to the last stage of said preheater by a gas outlet conduit.
2. An installation according to claim 1, wherein said gas outlet conduit has an angled configuration.
~ . An illustration according to any one of claims 1 and 2, wherein said junction cyclone is fed at its lowermost end with air issuing from said cooler.
4. An installation according to claim 1, wherein burners are provided at the basis of said junction cyclone.
5. An installation according to claim 1, which comprises two junction cyclones connected to said fumes outlet flue.
6. An installation according to claim 1, wherein said preheater comprises two cyclone columns, wherein said junction cyclone is connected to the last cyclone of one of said cyclone columns, and wherein the last cyclone of the other cyclone column is associated to a precalcinator fed with an air flow issuing from said cooler, into which the material issuing from said junction cyclone is introduced.
7. A process of calcinating powderous or granular material in an installation comprising a preheater, a rotary kiln and a cooler, wherein fumes issuing from said kiln are treated in a cyclone with a view to removing suspended matter from said fumes, whereafter said fumes are introduced into the last stage of a cooler.
?
?
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR7923130 | 1979-09-17 | ||
| FR7923130A FR2464742A1 (en) | 1979-09-17 | 1979-09-17 | PROCESS FOR PRECALCINATION OF PULVERULENT OR GRANULAR MATERIALS AND INSTALLATION FOR CARRYING OUT SAID METHOD |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1133249A true CA1133249A (en) | 1982-10-12 |
Family
ID=9229710
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA360,312A Expired CA1133249A (en) | 1979-09-17 | 1980-09-16 | Process and installation for precalcinating powderous or granular substances |
Country Status (4)
| Country | Link |
|---|---|
| CA (1) | CA1133249A (en) |
| DE (1) | DE3032803A1 (en) |
| FR (1) | FR2464742A1 (en) |
| GB (1) | GB2065279B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4568276A (en) * | 1984-02-15 | 1986-02-04 | Kabushiki Kaisha Kobe Seiko Sho | Dust preheating system with incipient calciner |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| BE524779A (en) * | ||||
| IT1110652B (en) * | 1978-02-10 | 1985-12-23 | Italcementi Spa | COMBINED PLANT FOR THE TREATMENT IN LONG OVENS BY HALF DRY OF MELME OF RAW MATERIALS FROM CONCRETE TO BE TRANSFORMED INTO CLINKER |
-
1979
- 1979-09-17 FR FR7923130A patent/FR2464742A1/en active Granted
-
1980
- 1980-08-30 DE DE19803032803 patent/DE3032803A1/en not_active Withdrawn
- 1980-09-15 GB GB8029773A patent/GB2065279B/en not_active Expired
- 1980-09-16 CA CA360,312A patent/CA1133249A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| FR2464742A1 (en) | 1981-03-20 |
| GB2065279B (en) | 1983-07-06 |
| GB2065279A (en) | 1981-06-24 |
| FR2464742B1 (en) | 1981-10-02 |
| DE3032803A1 (en) | 1981-04-02 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |