CA1087543A - Method and apparatus for calcining coke - Google Patents
Method and apparatus for calcining cokeInfo
- Publication number
- CA1087543A CA1087543A CA292,870A CA292870A CA1087543A CA 1087543 A CA1087543 A CA 1087543A CA 292870 A CA292870 A CA 292870A CA 1087543 A CA1087543 A CA 1087543A
- Authority
- CA
- Canada
- Prior art keywords
- coke
- kiln
- temperature
- gases
- burner
- 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
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- Muffle Furnaces And Rotary Kilns (AREA)
- Coke Industry (AREA)
- Carbon And Carbon Compounds (AREA)
Abstract
SPECIFICATION
ABSTRACT OF THE DISCLOSURE
A method and apparatus or calcining coke in a rotary kiln in which the heat for initially raising the temperature of the coke to evolve moisture and volatile gases from the coke and to ignite the volatile gases is supplied by a burner located at the upper end of the rotary kiln at which the coke is introduced into the kiln and in which the temperature of the coke is controlled downstream of the burner to continue evolving volatile gases without substantial loss of carbon due to burning by the introduc-tion of air into the kiln and in which the volatile gases and the gases of combustion are discharged at the lower end of the rotary kiln and the calcined coke is separated from the gases.
ABSTRACT OF THE DISCLOSURE
A method and apparatus or calcining coke in a rotary kiln in which the heat for initially raising the temperature of the coke to evolve moisture and volatile gases from the coke and to ignite the volatile gases is supplied by a burner located at the upper end of the rotary kiln at which the coke is introduced into the kiln and in which the temperature of the coke is controlled downstream of the burner to continue evolving volatile gases without substantial loss of carbon due to burning by the introduc-tion of air into the kiln and in which the volatile gases and the gases of combustion are discharged at the lower end of the rotary kiln and the calcined coke is separated from the gases.
Description
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This invention relates to a method and apparatus of calcining cokes, such as delayed or petroleum cokes, for the purpose of re~oving undesirable volatiles from the ~ ;
green coke and to densify it in order to provide an improved carbon product, for example, a carbon product, suitable for making electrodes of the type used in aluminum reduction cells.
The calcining process requires that the coke be heated to a high temperature within the rotary kiln to achieve the de~
volatilization and densification of the coke without substantial burning or oxidation of the carbon. ~ `
The calcining of cokes in rotary kilns is conventionally carried out in counterElow coke calcining rotary kilnsl that i9 to say, a rotary kiln in which the green coke enters the kiln at the upper end and moves downhill due to the rotation and slope of the kiln until it is discharged at the firing end of the kiln with the evolved volatile gases and the gases of -combustion flowing through the kiln in the opposite direction and discharged from the upper encl of the kiln.
In one type of conventional coke calcining rotary kilnl the green coke enters the kiln at one end and is -discharged at the firing end of the kiln while combustion air for the burner fuel and at least part of the combustion -air for the volatiles is introduced into the kiln through a -hood at the lower firing end thereo. In this arrangement ` ~-air and oxygen-rich gases are in contact with the hot coke where itreadily oxidizesl thereby resulting in burning of carbon which otherwise could be part of the product. The kiln atmosphere is reducing only where the coke is relatively ~ ' ~ .
This invention relates to a method and apparatus of calcining cokes, such as delayed or petroleum cokes, for the purpose of re~oving undesirable volatiles from the ~ ;
green coke and to densify it in order to provide an improved carbon product, for example, a carbon product, suitable for making electrodes of the type used in aluminum reduction cells.
The calcining process requires that the coke be heated to a high temperature within the rotary kiln to achieve the de~
volatilization and densification of the coke without substantial burning or oxidation of the carbon. ~ `
The calcining of cokes in rotary kilns is conventionally carried out in counterElow coke calcining rotary kilnsl that i9 to say, a rotary kiln in which the green coke enters the kiln at the upper end and moves downhill due to the rotation and slope of the kiln until it is discharged at the firing end of the kiln with the evolved volatile gases and the gases of -combustion flowing through the kiln in the opposite direction and discharged from the upper encl of the kiln.
In one type of conventional coke calcining rotary kilnl the green coke enters the kiln at one end and is -discharged at the firing end of the kiln while combustion air for the burner fuel and at least part of the combustion -air for the volatiles is introduced into the kiln through a -hood at the lower firing end thereo. In this arrangement ` ~-air and oxygen-rich gases are in contact with the hot coke where itreadily oxidizesl thereby resulting in burning of carbon which otherwise could be part of the product. The kiln atmosphere is reducing only where the coke is relatively ~ ' ~ .
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cold, that is, at the upper intake end of the kiln where burning of the carbon would be minimal anyway.
In another type of conventional counterflow coke calcining rotary kiln of the type described in U.S.
patent No. 3,966,560, issued June 29, ~976, the kiln atmosphere is controlled entirely by the combustion of -the volatile gases under the control of the air introduced mid-kiln and by an intermittently operated burner at the coke discharge end of the kiln, so that the atmosphere of the upper coke-intake end of the rotary kiln is controlled ; ;~
solely by the upstream countercurrent flow of the volatile and combustion gases. In kilns o this type, the hot coke at the lower discharge end comes in contact with air cap-abl~ o burning the carbonl although the rate o carbon burnout is less than in counterflow calciners of the type in which all of the air for the burner fuel and for burning the volatiles is introduced through the firing hood.
The object of the present invention is to provide a method and apparatus for affording greater control over the atmophere within the rotary kiln to make possible an improved and more efficient calcination o the coke, particularly a high degree of devolatilization and densification of the coke with a minimum or burning ~;~
or oxidation of the carbon content.
The present invention achievQs this objective by a paxallel flow coke calcining method and apparatus in ~` ~
which the coke is initially heated by a burner at the ~ ;
upper coke-intake end of the rotary kiln to raise the coke ~- :
~
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1~87S~3 `~` ~
cold, that is, at the upper intake end of the kiln where burning of the carbon would be minimal anyway.
In another type of conventional counterflow coke calcining rotary kiln of the type described in U.S.
patent No. 3,966,560, issued June 29, ~976, the kiln atmosphere is controlled entirely by the combustion of -the volatile gases under the control of the air introduced mid-kiln and by an intermittently operated burner at the coke discharge end of the kiln, so that the atmosphere of the upper coke-intake end of the rotary kiln is controlled ; ;~
solely by the upstream countercurrent flow of the volatile and combustion gases. In kilns o this type, the hot coke at the lower discharge end comes in contact with air cap-abl~ o burning the carbonl although the rate o carbon burnout is less than in counterflow calciners of the type in which all of the air for the burner fuel and for burning the volatiles is introduced through the firing hood.
The object of the present invention is to provide a method and apparatus for affording greater control over the atmophere within the rotary kiln to make possible an improved and more efficient calcination o the coke, particularly a high degree of devolatilization and densification of the coke with a minimum or burning ~;~
or oxidation of the carbon content.
The present invention achievQs this objective by a paxallel flow coke calcining method and apparatus in ~` ~
which the coke is initially heated by a burner at the ~ ;
upper coke-intake end of the rotary kiln to raise the coke ~- :
~
. ' .
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.. . . .
~37543 temperature to a level at which moisture and volatile gases are evolved ~rom the coke and the volatile gases '~
are ignited. Air is then introduced into the rotary ' kiln downstream of the burner to burn the greater part of the volatile gases evolved from the coke without dis~
integration of the coke. The combustion and any unburned volatile gases are discharged from the lower end of the rotary kiln and the calcined coke is separated from the discharged gases.
In the parallel flow arrangement of the present invention, the kiln atmosphere can be controlled throughout the length of the kiln to densify and devolatize the coke ~ith a minimum loss of carbon. In the upper region of the kiln where the green coke is introduced, the au~iliary fuel utilized by the burner serves to raise the temperature ' of the green coke to the level at which the volatiles are ~-~
evolved and igniting is commenced. The rate of such initial ;
heating to evolve and ignite the volatile gases can be balanced to achieve rapid heating while minimizing the breakdown of coke partlcles which cause undesirable dusting.
From that point on the heat required for the further temperature rise of the coke until complete calcination is accomplished is supplied by the combustion of the volatiles evolved from the coke with t,he temperature within the kiln controlled by the introduction of air into the kiln as it is required. Thus, in the region of the kiln at which the temperature of the coke is elevated to a level at which it ~ `
readily oxidizes, the kiln atmosphere is kept reducing due ,'i~,~
to the controlled air supply through mid-kiln ports. This -~ . ' ;~
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level of control permits the high temperatures requixed for the desulphurization of the coke to be achieved without disintegration and oxidation of the coke. Most of the heat :-required for calcination is supplied by the combustion of the : ~ :
volatiles evolved, and since practically all of the volatiles can be burned in the kiln proper without oxidation of the coke itself, a smaller incinerator will be required to burn the volatile gases discharged from the kiln than in conve~tional counterflow coke calcining kilns.
In accordance with one broad aspect, the invention ; ;
relates to a method of calcining coke in a single chamber of a sloped rotary kiln in which the coke travels from the upper feed end to the lower discharge end thereof comprising introducing the green coke to be calcined into an oxiclizing atmosphere containing a flame emanating fuel burner at the upper end of the kiln where the temperature of the green coke is well below the ignition temperature of the carbon to prevent carbon loss, heating the green coke by the radiant heat of the burner accommodated at the upper intake end of the rotary kiln to raise the green coke temperature to a level at which moisture and volatile gases are evolved fxom the coke, introducing ambient, unheated air into the rokary kiln at spaced apart intervals commencing downstream o tha moisture evolving burner region to burn the greater part of the volatile gases while increasing the temperature of the coke to continue evolving ::
volatile gases, the air being introduced at controlled rates and caused to flow in a concurrent direction to the flow of gases and combustion from the burner and to the flow of volatiles while maintaining a substantially reducing atmosphere for the coke in the region at which the temperature of the coke is elevated to a level at which it is capable of readily o:xidizing, ~,~ 5 ~7S9~3 ~ ~
discharging the combustion and volatile gases from the Lower discharge end of the rotary kiLn and separating the calcined coke rom the com~ustion gases at the lower discharge end of the rotary kiln.
For a complete understanding of thie present invention, ~ ;
reference can be made to the detailed description which ~ollows and to the accompanying drawings in which:
Fig. 1 iS a diagrammatic sectional view o a rotary kiln embodying the present invention; and Fig. 2 is a chart showing the temperature profiles of the coke bed and the gases throughout the length of the rotary kiln in a typical application of the present invention.
Referring ~o Fig. 1 of the drawings, ~he parallel 10w proces~ for calcining coke 10 is carried out in a ro-tary kiln 11 which is rotated about its longitudinal axis 12 through a ring gear 13 mounted to the outer periphery of the kiln and a ~
pinion 14 in mesh therewith and driven by a variable speed motor ;-,~- ; -15. The rotary kiln is sloped from the upper end to the lower `
end to move the coke bed through the kiln as the kiln rotates.
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The upper end of the rotary kiln is enclosed by a hood 16 having spillage passage 17 therein~ The green coke to be calcined is fed through the hood into the upper end of the rotary kiln through a feed condùit 18.
A regular feed pipe without any seal to block the inflow of air can be used because there are no volatiles or combustion gases flowing through the kiln in counterflow direction to the feed of the coke. The lower discharge end of the rotary kiln opens into an incinerator 19 or into a duct which con-ducts the gases discharged from the kiln into an incinerator,heat boiler or the like to recover the available heat in the discharged gases. The duct or incinerator 19 also has a depending discharge passage 20 therein ~or separating the calcined coke from the gases.
The upper end of the rotary kiln contains a burner 21 which heats the upper coke intake zone of the :
rotary kiln to remove the moisture from the feed, to raise the temperature thereof to a level at which volatile gases are evolved and to ignite the volatile gases. Downstream of this zone, air is introduced into the rotary kiln to burn the volatile gases and to continue the devolatilization and densification of the coke. The air is supplied to the kiln in spaced stages by fans or blowers 22 which supply air into manifolds 23 with which radially disposed tuyeres or conduits 24 communicate to discharge the air -~ ~
from ports in a downstream direction along the longitudinal ~ -a~is of the rotary kiln. The fans or blowers 22 are shown mounted on the shPll of the rotary kiln, but the air can . ,': ':
-6- ~
'~ : ' '' .
: ' .
1~1875~L3 also be supplied by stationary fans to the kiln through ~`
suitable manifold ductwork mounted to the shell of the rotary kiln.
The volatiles continue to be evolved from the coke by the combustion of the volatile gases under the control of the air supplied to the kiln, and the temperature of the coke is raised to the level at which `
substantially complete devolatilization is achieved, that is to say, to produce a coke product containing less than 0.5% volatiles. The combustion gases along with any un-burned volatile gases are discharged into the duct or in-cinerator 19, and the calcined coke falls by gravity from the lower discharge end of the kiln into the discharge passage 20.
The parallel flow coke calcining system o~
the present invention can be controlled with high precision at each of the stages of the kiln to achieve a high level of devolatilization, desulphurization and densification of the coke without substantial burning or oxidation of the ~`
carbon. In the intake preheat zone of the kiln the rate of temperature increase can be controlled by the amount of ; -fuel burned by the burner 21 and b~ the shape and len~th ~;
of the flame, thereby insuring a high degree of initial volatile evolution necessary to bring the volatile gases . . .
to the ignition temperature at the proper point within the -~ - --kiln without excessive dusting of the coke. Thereafter, ; ~ ;
the introduction o mid-kiln air is supplied at a rate necessary to continue the evolving and burning of the vol-atiles and to increase the coke temperature. In the zone :.: : . . : :.
--~ 10i~375~3 defined by the last 30% of travel of the coke through the kiln the coke is heated in -the range of 2400 to 2800F., depending on the desired product quality and amount of sulphur content of the coke. The upper end of that range, that is to say, about 2800F., is the temperature required for thorough desulphurization of the coke.
Thorough devolatilization, densification and desulphuri-zation of the coke to less than 0.5% volatiles can be achieved through controlled burning of from 80 to 100 of the volatiles in contrast to burning about 25% of evolved volatiles in conventional counterflow rotary cal-ciners without mid-kiln air inlets and about 30 to 35 evolved volatiles in conventional counterflow rotary calciners with mid-kiln air inlets. Because the burner fuel is required only to raise the coke temperature to the level at which the volatiles start evolving and the re-mainder of the calcining heat is provided by burning all or substantially all of the evolved volatiles, as required, in the kiln proper, the auxiliary fuel consumption utilized by the burner is very low, in the order of 25~ of the total heat requirement. Moreover, a smaller incinerator will be required to complete the burning of the volatile gases.
The draft through the kiln to carry the vol-atile gases and combustion gases at the desired controlled rate toward the lower discharge end and then through the ~ -duct or incinerator 19 can be accomplished by a stack 25 or a blower downstream of the duct or the incinerator or waste heat boiler utilized for burning the unburned volatilesr .':
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:
1~7543 : ~
The present invention permits the kiln atmos~
phere to be controlled throughout the length thereof to suit the process. By controlling the flame shape and ~ -~
firing rate of the burner, the draft through the kiln and the air introduced into the kiln, the temperature rise of the feed can be controlled and the disintegration of the coke which would cause undesirable dusting and carbon loss can be avoided. Also, the oxidizing atmos- ~ ;
phere within the kiln is confined to the initial preheat zone where the coke temperature is well below the ignition temperature of the carbon. The hot coke does not come into contact with air or oxidizing gases because the kiln atmosphere can be properly controlled b~ controlling the air introduced for the combustion of the volatiles through the mid-kiln inlet ports, the amount of air being control led by speed control of the fans or inlet damper adjustment.
The invention has been shown and described in preferred form and by way of example only, and different variations and modifications can be made therein within the spirit of the invention. The invention, therefore, ;
is not intended to be limited to any particular form or embodiment except insofar as such limitations are expressly ;
set forth in the claims.
' ;~:
''' "'"
.. . . .
~37543 temperature to a level at which moisture and volatile gases are evolved ~rom the coke and the volatile gases '~
are ignited. Air is then introduced into the rotary ' kiln downstream of the burner to burn the greater part of the volatile gases evolved from the coke without dis~
integration of the coke. The combustion and any unburned volatile gases are discharged from the lower end of the rotary kiln and the calcined coke is separated from the discharged gases.
In the parallel flow arrangement of the present invention, the kiln atmosphere can be controlled throughout the length of the kiln to densify and devolatize the coke ~ith a minimum loss of carbon. In the upper region of the kiln where the green coke is introduced, the au~iliary fuel utilized by the burner serves to raise the temperature ' of the green coke to the level at which the volatiles are ~-~
evolved and igniting is commenced. The rate of such initial ;
heating to evolve and ignite the volatile gases can be balanced to achieve rapid heating while minimizing the breakdown of coke partlcles which cause undesirable dusting.
From that point on the heat required for the further temperature rise of the coke until complete calcination is accomplished is supplied by the combustion of the volatiles evolved from the coke with t,he temperature within the kiln controlled by the introduction of air into the kiln as it is required. Thus, in the region of the kiln at which the temperature of the coke is elevated to a level at which it ~ `
readily oxidizes, the kiln atmosphere is kept reducing due ,'i~,~
to the controlled air supply through mid-kiln ports. This -~ . ' ;~
''"''' ~ ' "
~7S4;~
level of control permits the high temperatures requixed for the desulphurization of the coke to be achieved without disintegration and oxidation of the coke. Most of the heat :-required for calcination is supplied by the combustion of the : ~ :
volatiles evolved, and since practically all of the volatiles can be burned in the kiln proper without oxidation of the coke itself, a smaller incinerator will be required to burn the volatile gases discharged from the kiln than in conve~tional counterflow coke calcining kilns.
In accordance with one broad aspect, the invention ; ;
relates to a method of calcining coke in a single chamber of a sloped rotary kiln in which the coke travels from the upper feed end to the lower discharge end thereof comprising introducing the green coke to be calcined into an oxiclizing atmosphere containing a flame emanating fuel burner at the upper end of the kiln where the temperature of the green coke is well below the ignition temperature of the carbon to prevent carbon loss, heating the green coke by the radiant heat of the burner accommodated at the upper intake end of the rotary kiln to raise the green coke temperature to a level at which moisture and volatile gases are evolved fxom the coke, introducing ambient, unheated air into the rokary kiln at spaced apart intervals commencing downstream o tha moisture evolving burner region to burn the greater part of the volatile gases while increasing the temperature of the coke to continue evolving ::
volatile gases, the air being introduced at controlled rates and caused to flow in a concurrent direction to the flow of gases and combustion from the burner and to the flow of volatiles while maintaining a substantially reducing atmosphere for the coke in the region at which the temperature of the coke is elevated to a level at which it is capable of readily o:xidizing, ~,~ 5 ~7S9~3 ~ ~
discharging the combustion and volatile gases from the Lower discharge end of the rotary kiLn and separating the calcined coke rom the com~ustion gases at the lower discharge end of the rotary kiln.
For a complete understanding of thie present invention, ~ ;
reference can be made to the detailed description which ~ollows and to the accompanying drawings in which:
Fig. 1 iS a diagrammatic sectional view o a rotary kiln embodying the present invention; and Fig. 2 is a chart showing the temperature profiles of the coke bed and the gases throughout the length of the rotary kiln in a typical application of the present invention.
Referring ~o Fig. 1 of the drawings, ~he parallel 10w proces~ for calcining coke 10 is carried out in a ro-tary kiln 11 which is rotated about its longitudinal axis 12 through a ring gear 13 mounted to the outer periphery of the kiln and a ~
pinion 14 in mesh therewith and driven by a variable speed motor ;-,~- ; -15. The rotary kiln is sloped from the upper end to the lower `
end to move the coke bed through the kiln as the kiln rotates.
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: ,' ,~. , `
` -5a-~L0~75~3 :
The upper end of the rotary kiln is enclosed by a hood 16 having spillage passage 17 therein~ The green coke to be calcined is fed through the hood into the upper end of the rotary kiln through a feed condùit 18.
A regular feed pipe without any seal to block the inflow of air can be used because there are no volatiles or combustion gases flowing through the kiln in counterflow direction to the feed of the coke. The lower discharge end of the rotary kiln opens into an incinerator 19 or into a duct which con-ducts the gases discharged from the kiln into an incinerator,heat boiler or the like to recover the available heat in the discharged gases. The duct or incinerator 19 also has a depending discharge passage 20 therein ~or separating the calcined coke from the gases.
The upper end of the rotary kiln contains a burner 21 which heats the upper coke intake zone of the :
rotary kiln to remove the moisture from the feed, to raise the temperature thereof to a level at which volatile gases are evolved and to ignite the volatile gases. Downstream of this zone, air is introduced into the rotary kiln to burn the volatile gases and to continue the devolatilization and densification of the coke. The air is supplied to the kiln in spaced stages by fans or blowers 22 which supply air into manifolds 23 with which radially disposed tuyeres or conduits 24 communicate to discharge the air -~ ~
from ports in a downstream direction along the longitudinal ~ -a~is of the rotary kiln. The fans or blowers 22 are shown mounted on the shPll of the rotary kiln, but the air can . ,': ':
-6- ~
'~ : ' '' .
: ' .
1~1875~L3 also be supplied by stationary fans to the kiln through ~`
suitable manifold ductwork mounted to the shell of the rotary kiln.
The volatiles continue to be evolved from the coke by the combustion of the volatile gases under the control of the air supplied to the kiln, and the temperature of the coke is raised to the level at which `
substantially complete devolatilization is achieved, that is to say, to produce a coke product containing less than 0.5% volatiles. The combustion gases along with any un-burned volatile gases are discharged into the duct or in-cinerator 19, and the calcined coke falls by gravity from the lower discharge end of the kiln into the discharge passage 20.
The parallel flow coke calcining system o~
the present invention can be controlled with high precision at each of the stages of the kiln to achieve a high level of devolatilization, desulphurization and densification of the coke without substantial burning or oxidation of the ~`
carbon. In the intake preheat zone of the kiln the rate of temperature increase can be controlled by the amount of ; -fuel burned by the burner 21 and b~ the shape and len~th ~;
of the flame, thereby insuring a high degree of initial volatile evolution necessary to bring the volatile gases . . .
to the ignition temperature at the proper point within the -~ - --kiln without excessive dusting of the coke. Thereafter, ; ~ ;
the introduction o mid-kiln air is supplied at a rate necessary to continue the evolving and burning of the vol-atiles and to increase the coke temperature. In the zone :.: : . . : :.
--~ 10i~375~3 defined by the last 30% of travel of the coke through the kiln the coke is heated in -the range of 2400 to 2800F., depending on the desired product quality and amount of sulphur content of the coke. The upper end of that range, that is to say, about 2800F., is the temperature required for thorough desulphurization of the coke.
Thorough devolatilization, densification and desulphuri-zation of the coke to less than 0.5% volatiles can be achieved through controlled burning of from 80 to 100 of the volatiles in contrast to burning about 25% of evolved volatiles in conventional counterflow rotary cal-ciners without mid-kiln air inlets and about 30 to 35 evolved volatiles in conventional counterflow rotary calciners with mid-kiln air inlets. Because the burner fuel is required only to raise the coke temperature to the level at which the volatiles start evolving and the re-mainder of the calcining heat is provided by burning all or substantially all of the evolved volatiles, as required, in the kiln proper, the auxiliary fuel consumption utilized by the burner is very low, in the order of 25~ of the total heat requirement. Moreover, a smaller incinerator will be required to complete the burning of the volatile gases.
The draft through the kiln to carry the vol-atile gases and combustion gases at the desired controlled rate toward the lower discharge end and then through the ~ -duct or incinerator 19 can be accomplished by a stack 25 or a blower downstream of the duct or the incinerator or waste heat boiler utilized for burning the unburned volatilesr .':
..~ . ' .
:
1~7543 : ~
The present invention permits the kiln atmos~
phere to be controlled throughout the length thereof to suit the process. By controlling the flame shape and ~ -~
firing rate of the burner, the draft through the kiln and the air introduced into the kiln, the temperature rise of the feed can be controlled and the disintegration of the coke which would cause undesirable dusting and carbon loss can be avoided. Also, the oxidizing atmos- ~ ;
phere within the kiln is confined to the initial preheat zone where the coke temperature is well below the ignition temperature of the carbon. The hot coke does not come into contact with air or oxidizing gases because the kiln atmosphere can be properly controlled b~ controlling the air introduced for the combustion of the volatiles through the mid-kiln inlet ports, the amount of air being control led by speed control of the fans or inlet damper adjustment.
The invention has been shown and described in preferred form and by way of example only, and different variations and modifications can be made therein within the spirit of the invention. The invention, therefore, ;
is not intended to be limited to any particular form or embodiment except insofar as such limitations are expressly ;
set forth in the claims.
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''' "'"
Claims (5)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A method of calcining coke in a single chamber of a sloped rotary kiln in which the coke travels from the upper feed end to the lower discharge end thereof comprising introducing the green coke to be calcined into an oxidizing atmosphere containing a flame emanating fuel burner at the upper end of the kiln where the temperature of the green coke is well below the ig-nition temeprature of the carbon to prevent carbon loss, heating the green coke by the radiant heat of the burner accommodated at the upper intake end of the rotary kiln to raise the green coke temperature to a level at which moisture and volatile gases are evolved from the coke, introducing ambient, unheated air into the rotary kiln at spaced apart intervals commencing downstream of the mois-ture evolving burner region to burn the greater part of the volatile gases while increasing the temperature of the coke to continue evolving volatile gases, the air being introduced at controlled rates and caused to flow in a concurrent direction to the flow of gases of combus-tion from the burner and to the flow of volatiles while maintaining a substantially reducing atmosphere for the coke in the region at which the temperature of the coke is elevated to a level at which it is capable of readily oxidizing, discharging the combustion and volatile gases from the lower discharge end of the rotary kiln and sepa-rating the calcined coke from the combustion gases at the lower discharge end of the rotary kiln.
2. A method of calcining coke as set forth in claim 1 in which the heat of the burner raises the temperature of the coke in an initial preheat zone to the ignition temperature of the volatile gases and in which the coke is heated downstream of said initial zone by the combustion of the volatile gases to a level in the order of 2400 to 2800°F. in the final 30% of the length of the rotary kiln to reduce the volatile content of the coke to less than 0.5% volatiles.
3. A method of calcining coke as set forth in claim 2 in which the rate of air is admitted to bring the temperature of the coke to a level of about 2800°F.
to substantially desulphurize the coke without substantial burning of the carbon content of the coke.
to substantially desulphurize the coke without substantial burning of the carbon content of the coke.
4. A method of calcining coke as set forth in claim 2 including burning at least 80% of the evolved volatiles in the kiln.
5. A method of calcining coke as set forth in claim 1 including evolving and burning volatiles and supply-ing air at various stages commencing at a cooler region of the kiln to burn the volatiles to carry on the calcination of the coke so that the fuel consumption of the burner does not exceed 25% of the total heat requirement for calcining the coke.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US77009877A | 1977-02-18 | 1977-02-18 | |
| US770,098 | 1977-02-18 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1087543A true CA1087543A (en) | 1980-10-14 |
Family
ID=25087472
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA292,870A Expired CA1087543A (en) | 1977-02-18 | 1977-12-12 | Method and apparatus for calcining coke |
Country Status (5)
| Country | Link |
|---|---|
| JP (1) | JPS53102901A (en) |
| AU (1) | AU3168177A (en) |
| BR (1) | BR7800954A (en) |
| CA (1) | CA1087543A (en) |
| IT (1) | IT1102370B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112877086A (en) * | 2021-01-25 | 2021-06-01 | 焦作钧菲津材科技有限公司 | Petroleum coke calcination control method |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2158088B (en) * | 1984-04-18 | 1988-12-29 | Exxon Research Engineering Co | Process and apparatus for the production of calcined coke |
-
1977
- 1977-12-12 CA CA292,870A patent/CA1087543A/en not_active Expired
- 1977-12-16 AU AU31681/77A patent/AU3168177A/en active Pending
-
1978
- 1978-01-09 JP JP61078A patent/JPS53102901A/en active Pending
- 1978-02-17 BR BR7800954A patent/BR7800954A/en unknown
- 1978-02-17 IT IT48090/78A patent/IT1102370B/en active
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112877086A (en) * | 2021-01-25 | 2021-06-01 | 焦作钧菲津材科技有限公司 | Petroleum coke calcination control method |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS53102901A (en) | 1978-09-07 |
| IT7848090A0 (en) | 1978-02-17 |
| AU3168177A (en) | 1979-06-21 |
| BR7800954A (en) | 1978-11-28 |
| IT1102370B (en) | 1985-10-07 |
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