CA1127463A - Combination of a coal grinding drying process and a coal heating process with increased heat recovery - Google Patents
Combination of a coal grinding drying process and a coal heating process with increased heat recoveryInfo
- Publication number
- CA1127463A CA1127463A CA353,351A CA353351A CA1127463A CA 1127463 A CA1127463 A CA 1127463A CA 353351 A CA353351 A CA 353351A CA 1127463 A CA1127463 A CA 1127463A
- Authority
- CA
- Canada
- Prior art keywords
- coal
- fuel
- air
- dust
- mill
- 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
- F27B7/38—Arrangements of cooling devices
- F27B7/383—Cooling devices for the charge
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B02—CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
- B02C—CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
- B02C21/00—Disintegrating plant with or without drying of the material
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23K—FEEDING FUEL TO COMBUSTION APPARATUS
- F23K1/00—Preparation of lump or pulverulent fuel in readiness for delivery to combustion apparatus
- F23K1/04—Heating fuel prior to delivery to combustion apparatus
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23K—FEEDING FUEL TO COMBUSTION APPARATUS
- F23K3/00—Feeding or distributing of lump or pulverulent fuel to combustion apparatus
- F23K3/02—Pneumatic feeding arrangements, i.e. by air blast
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P40/00—Technologies relating to the processing of minerals
- Y02P40/10—Production of cement, e.g. improving or optimising the production methods; Cement grinding
Abstract
ABSTRACT OF THE DISCLOSURE
The present invention provides a process of coal grinding, drying and coal firing in which the coal is ground and dried in a mill and a portion of exhaust air from the mill containing coal dust is passed as primary air to a coal firing furnace the improvement in which the portion of the coal dust-containing exhaust air of the mill which is not used as primary air is used for heating secondary air in the furnace or for cooling the hot material in the furnace or both.
The present invention provides a process of coal grinding, drying and coal firing in which the coal is ground and dried in a mill and a portion of exhaust air from the mill containing coal dust is passed as primary air to a coal firing furnace the improvement in which the portion of the coal dust-containing exhaust air of the mill which is not used as primary air is used for heating secondary air in the furnace or for cooling the hot material in the furnace or both.
Description
The present inven~ion relates to a process of coal grinding, drying and coal firing which is easy on the environment and saves energy by minimizing thè amount of primary air even at high moisture contents oE the coal.
In process furnaces ~lame formation has a substantial effect on energy consumption. For a low energy consumption a fast combustion with favourable heat transfer by a short and hot flame is required. Apar~ from other factors important parameters for this purpose are: the proportion of primary air, the temperature of both the primary air and the secondary air, and the injection impulse ratios. The proportion of primary air should be as small as possible and the temperatures of both the primary air and the secondary air as high as possible. The rate of injection and the torque component of the combustlon in the furnace should be freely selectable within an optimal range.
The following methods ~fcoal firing are known.
1. lndirect firlng
In process furnaces ~lame formation has a substantial effect on energy consumption. For a low energy consumption a fast combustion with favourable heat transfer by a short and hot flame is required. Apar~ from other factors important parameters for this purpose are: the proportion of primary air, the temperature of both the primary air and the secondary air, and the injection impulse ratios. The proportion of primary air should be as small as possible and the temperatures of both the primary air and the secondary air as high as possible. The rate of injection and the torque component of the combustlon in the furnace should be freely selectable within an optimal range.
The following methods ~fcoal firing are known.
1. lndirect firlng
2. direct firlng
3. semidirect firing with and without an additional filter.
In indirect firing the coal ~rinding drying unit is operated completely independently of the furnace firing. In fact in this process the determining factors for flame formation can be optimized independently of the grinding drying unit.
However, a separate filter for purifying the dust-containing grinding mill exhaust air and an intermediate storage bin for the ground dry coal are required. Such a process is hazardous because of coal-dust explosions and fires. Moreover, the expenditures for the required capital, maintenance and operation are high.
In direct firing the entire coal-dust containing grinding millexhaust air is injected into the process furnace.
~.
9 ~2~i3 The capital costs are substantially lower since, for example, a separate filter for purifying the dust-containing grinding mill exhaust air and an i~ltermediate storage bin for the ground dry coal are avoided. Because of the absence of these intermediate uni~cs and of the required intermediate steps the danger of coal-dust explosions and fires is substantially reduced. High proportions of primary air are a disadvantage. Therefore, optimal injection impulse ratios at the furnace burner cannot be attained.
In semidirect firing, the coal dust contained in the ex~aust air of the grinding mill is first removed in a cyclone.
A portion of this air is returned to the mill unit as recycled air and serves as additional carrier air in the mill while the residual air together with the coal dust separated in the cyclone is injected into the furnace. At high coal moisture and mill heating with low -cemperatures the amount of exhaust air resulting from the drying procedure is greater than that correspond-ing to the re~uired amount of carrier air. Therefore, in these cases a high amount of primary air must be accepted or an ~0 additional filter must be ins~alled, thus resulting in disadvantages similar to those in direct and indirect firing. Thus a high amount of prima~y air prevents the injection impulse ratios at the furnace burner from being optimized and an addifcional filter means additional capital costs and increased danger of coal dust explosions and fires.
The present invention provides a process in which the proportion of primary air can be kept selectively small irrespec-tive of the coal moisture content and the heating of the grinding mill and where the injection ratios at the burner nozzle are adjustable independently of the grinding drying process, without having to accept a separate coal dust filter or an intermediate s-torage bin and the safety risks and additional costs associated ~Z7~
therewith, as for example, in indirect firing, and in which the heat of the exhaust air of the ~rinding mill can be recovered.
According to the present invention there is provided a method for using solid fuel to heat a kiln which discharges heated materials to a cooler, comprising: pulverizing the fuel in a mill;
pneumatically conveying the pulverized fuel to a separator for sepa-rating fuel particles from fuel-dust-laden air; pneumatically con-veying the separated fuel particles to -the kiln for burning; and conveying at least a portion of the fuel-dust-laden air to the cooler.
Thus, according to a preferred embodiment of the inven-tion the proportion of coal-dust containing exhaust air of the grinding mill which is not required as primary air is used for heat-ing the secondary air and/or for cooling the heated material.
In another preferred embodiment of the present invention the portion of the mill exhaust air which is not required as pri-mary air and from which the dust has been removed by means of a pre-liminary purification, particularly with the aid of a cyclone, is used for cooling the heated material and/or for heating the secondary air so that the heat from the heated material can also be recovered for heating the exhaust air of the grinding mill.
~ n another preferred embodiment of the present inven-tion, the hot coal-dust containing exhaust air of the grinding mill is injected into the hot front end of the clinker cooler so that the heat is also recovered in this zone and that moreover, the residual coal dust ignites in this hot zone and thus is sub-stantially removed and also advantageously heats the secondary air.
In yet another preferred embodiment of the present inven-tion the exhaust air of the grinding mill, from which the dust has been remo~ed by means of a preliminary purification, is inject-ed below the grate of the clinker cooler.
' ! , ~'74~i3 In a further preferred embodiment of the present invention the exhaust air of the grinding mill, from which the dust has been removed by means o~ a preliminary purification, is injected above the ~rate of the clinker cooler.
In another manner of carry1ng out the process accordir.y to the invention hot air from the clinker cooler or from the top of the furnace is used for drying the coal.
In a further embodiment of the present invention hot exhaust gas of the furnace unit is used for drying the air.
However, in a further special embodiment separate firing is used for drying the coal.
The process according to the invention is suitable particularly for burning cement clinker, lime or expanded clay in a rotary furnace system with a series-connected planetary, flash, tunnel or fluidized hed cooler. Said process is also suitable for burning cement clinker, lime or expanded clay when using a shaft or carriage furnace. Moreover, the process according to the invention is suitable when using a roll mill or a ball mill for the grinding drying operation. Finally the ~0 process according to the invention is also suitable in cases in which pure coal firing or mixed firing with coal and other fuels is used. The above possibilities of using the process according to the invention are only examples.
Thus, in accordance with the present invention, it is possible to reduce the amount of primary air for the furnace burner to the minimum required for an optimal combustion, irrespective of the grinding drying system and the moistu~e content of the coal while simultaneously using the residual amount of yrlnding mill exhaust air without a separate filter system in a manner which is easy on the environment. ~oreover the process according to the invention saves energy since the heat from the hot exhaust alr of the mill is reused for heating i3 the secondary air. Furthermore, the residual coal dust of the exhaust air of the grinding mill is fed to the secondary air so that it need not be filtered out. More specifically this residual coal dust can be burned in the secondary air flow according to a special embodiment of the process of the invention.
This means a more direct and complete utilization of the entire coal dust of the exhaust air o~ the mill so that not only does the process accordlng to the invention save energy and raw material but it also is easy on the environment and less costly since the coal dust is removed and a separate filter system is no lon~er required.
Furthermore because of the absence of both an inter-mediate storage bin for the coal dust and the filter unit and since the corresponding gr~nding drying svstem can be operated and rendered ~nert with low hot air temperatures even at high coal moistures without heat economy l~sses the process according to the invention provides a hi~h de~ree of safety against coal dust explosions and fires, and even high coal moisture contents can be overcome without any problems by the extensive use of waste heat of the furnace and/or of the clinker cooler.
The process according to the invention is further illustrated by way of the accompanying drawing which diagram- ~ ~
matically shows a system operated by means of the process accord-ing to the invention. The system comprises particularly a cement-making furnace with a thrust-grating clinker cooler.
The coal dr~ed and ground in a coal mill 1 is separated in a high-speed cyclone 2 and is fed via a shut-off valve 3 into the primary air flow or int~ a partial air flow of the primary air 4.
The amount of gas or air required for drying and as the carrier air is sucked by the blower system 5 through the coal mill 1 and the high-speed cyclone 2. As the conveying medium
In indirect firing the coal ~rinding drying unit is operated completely independently of the furnace firing. In fact in this process the determining factors for flame formation can be optimized independently of the grinding drying unit.
However, a separate filter for purifying the dust-containing grinding mill exhaust air and an intermediate storage bin for the ground dry coal are required. Such a process is hazardous because of coal-dust explosions and fires. Moreover, the expenditures for the required capital, maintenance and operation are high.
In direct firing the entire coal-dust containing grinding millexhaust air is injected into the process furnace.
~.
9 ~2~i3 The capital costs are substantially lower since, for example, a separate filter for purifying the dust-containing grinding mill exhaust air and an i~ltermediate storage bin for the ground dry coal are avoided. Because of the absence of these intermediate uni~cs and of the required intermediate steps the danger of coal-dust explosions and fires is substantially reduced. High proportions of primary air are a disadvantage. Therefore, optimal injection impulse ratios at the furnace burner cannot be attained.
In semidirect firing, the coal dust contained in the ex~aust air of the grinding mill is first removed in a cyclone.
A portion of this air is returned to the mill unit as recycled air and serves as additional carrier air in the mill while the residual air together with the coal dust separated in the cyclone is injected into the furnace. At high coal moisture and mill heating with low -cemperatures the amount of exhaust air resulting from the drying procedure is greater than that correspond-ing to the re~uired amount of carrier air. Therefore, in these cases a high amount of primary air must be accepted or an ~0 additional filter must be ins~alled, thus resulting in disadvantages similar to those in direct and indirect firing. Thus a high amount of prima~y air prevents the injection impulse ratios at the furnace burner from being optimized and an addifcional filter means additional capital costs and increased danger of coal dust explosions and fires.
The present invention provides a process in which the proportion of primary air can be kept selectively small irrespec-tive of the coal moisture content and the heating of the grinding mill and where the injection ratios at the burner nozzle are adjustable independently of the grinding drying process, without having to accept a separate coal dust filter or an intermediate s-torage bin and the safety risks and additional costs associated ~Z7~
therewith, as for example, in indirect firing, and in which the heat of the exhaust air of the ~rinding mill can be recovered.
According to the present invention there is provided a method for using solid fuel to heat a kiln which discharges heated materials to a cooler, comprising: pulverizing the fuel in a mill;
pneumatically conveying the pulverized fuel to a separator for sepa-rating fuel particles from fuel-dust-laden air; pneumatically con-veying the separated fuel particles to -the kiln for burning; and conveying at least a portion of the fuel-dust-laden air to the cooler.
Thus, according to a preferred embodiment of the inven-tion the proportion of coal-dust containing exhaust air of the grinding mill which is not required as primary air is used for heat-ing the secondary air and/or for cooling the heated material.
In another preferred embodiment of the present invention the portion of the mill exhaust air which is not required as pri-mary air and from which the dust has been removed by means of a pre-liminary purification, particularly with the aid of a cyclone, is used for cooling the heated material and/or for heating the secondary air so that the heat from the heated material can also be recovered for heating the exhaust air of the grinding mill.
~ n another preferred embodiment of the present inven-tion, the hot coal-dust containing exhaust air of the grinding mill is injected into the hot front end of the clinker cooler so that the heat is also recovered in this zone and that moreover, the residual coal dust ignites in this hot zone and thus is sub-stantially removed and also advantageously heats the secondary air.
In yet another preferred embodiment of the present inven-tion the exhaust air of the grinding mill, from which the dust has been remo~ed by means of a preliminary purification, is inject-ed below the grate of the clinker cooler.
' ! , ~'74~i3 In a further preferred embodiment of the present invention the exhaust air of the grinding mill, from which the dust has been removed by means o~ a preliminary purification, is injected above the ~rate of the clinker cooler.
In another manner of carry1ng out the process accordir.y to the invention hot air from the clinker cooler or from the top of the furnace is used for drying the coal.
In a further embodiment of the present invention hot exhaust gas of the furnace unit is used for drying the air.
However, in a further special embodiment separate firing is used for drying the coal.
The process according to the invention is suitable particularly for burning cement clinker, lime or expanded clay in a rotary furnace system with a series-connected planetary, flash, tunnel or fluidized hed cooler. Said process is also suitable for burning cement clinker, lime or expanded clay when using a shaft or carriage furnace. Moreover, the process according to the invention is suitable when using a roll mill or a ball mill for the grinding drying operation. Finally the ~0 process according to the invention is also suitable in cases in which pure coal firing or mixed firing with coal and other fuels is used. The above possibilities of using the process according to the invention are only examples.
Thus, in accordance with the present invention, it is possible to reduce the amount of primary air for the furnace burner to the minimum required for an optimal combustion, irrespective of the grinding drying system and the moistu~e content of the coal while simultaneously using the residual amount of yrlnding mill exhaust air without a separate filter system in a manner which is easy on the environment. ~oreover the process according to the invention saves energy since the heat from the hot exhaust alr of the mill is reused for heating i3 the secondary air. Furthermore, the residual coal dust of the exhaust air of the grinding mill is fed to the secondary air so that it need not be filtered out. More specifically this residual coal dust can be burned in the secondary air flow according to a special embodiment of the process of the invention.
This means a more direct and complete utilization of the entire coal dust of the exhaust air o~ the mill so that not only does the process accordlng to the invention save energy and raw material but it also is easy on the environment and less costly since the coal dust is removed and a separate filter system is no lon~er required.
Furthermore because of the absence of both an inter-mediate storage bin for the coal dust and the filter unit and since the corresponding gr~nding drying svstem can be operated and rendered ~nert with low hot air temperatures even at high coal moistures without heat economy l~sses the process according to the invention provides a hi~h de~ree of safety against coal dust explosions and fires, and even high coal moisture contents can be overcome without any problems by the extensive use of waste heat of the furnace and/or of the clinker cooler.
The process according to the invention is further illustrated by way of the accompanying drawing which diagram- ~ ~
matically shows a system operated by means of the process accord-ing to the invention. The system comprises particularly a cement-making furnace with a thrust-grating clinker cooler.
The coal dr~ed and ground in a coal mill 1 is separated in a high-speed cyclone 2 and is fed via a shut-off valve 3 into the primary air flow or int~ a partial air flow of the primary air 4.
The amount of gas or air required for drying and as the carrier air is sucked by the blower system 5 through the coal mill 1 and the high-speed cyclone 2. As the conveying medium
4~3 and dryin~ medium upstrea~ of the coal mill 1 either hot cooler air through the cooler ~ix pipe 6 or hot air ~rom the furnace top through the furnace top air pipe 7, furnace exhaust gas through the furnace exhaust gas pipe 8, hot ~as from a combustion chamber 9, or combinations of cooler air, ~urnace top air, furnace flue gas and hot gas are used, the cooler air valve 10, the furnace air choke 11, the furnace flue gas choke 12 and the combustion chamber choke 13 or the cold air valve 30 being used for adjusting the flows. The dust-containing hot air is subjected to preliminary purification in a cyclone 14. The coal-dust containin~ exhaust air of the mill 1, from which the dust has been removed in the high-speed cyclone 2, is divided downstream of the blower system 5 and can be conveyed to the primary air blower 15, to the inlet of the mill 1 via the connecting pipe valve 19 through the connecting pipe 18 or to a cooling air blower 16 o~ the clinker cooler 17. The proportions o~ the various amounts can be optimized depending on the requirements of the system, the coal moisture content and the flame formation and can be adjusted in the range from 0 to ~0 100~. For this purpose the connecting pipe valve 19, the cooling air supply valve 20 and the auxiliary valve 21 as well as the primary air valve 22 and the valve 23 for admixing cold air are used.
By these adjusting means the proportion of primary air can be reduced optionally and the most varied burner nozzles 24 and combinations of firing, for example, with additional fuel 36, can be used without having to take into account the coal moisture content and the conditions at the grinding drying unit.
Thus, for example, particularly at high coal moisture contents a higher proportion of exhaust air is injected into the clinker cooler. The injection procedure is carried out, for 41~3 example, with an existing cooling air blower 16, like that shown in the Figure, or directly into one of the cooling chambers 31, the latter procedure is not shown in the Figure. ~lowever, the injection pr~cedure can also be distributed over several cooling air blowers 16 or it can even be carried out with a separate cooling air feed blower 34 into one or several cooling air chambers 31 or directly into the hot air end of the clinker, cooler 37 via the grate 25, but preferably into the cooling air chambers 31 closest to the hot air end of the clinker coolex.
The thermal heat of the exhaust air from the mill 1, can thus be fully utilized for heating the secondary air. Furthermore, the portion of non-thermal heat still contained in the mill exhaust air in the form of the residual coal dust content is i~nited on passing through the hot clinker layer and further heats the secondary air. The excess exhaust air from the cooler is passed via the exhaust air pipe 32 to the exhaust air dust collector 27, where~the dust is removed. With the aid of both the exhaust air blower 28 and the contrQl valve 29 the exhaust air, as a function of the pressure ln the furnace top, is released into the atmosphere.
In the l~rocess according to the invention the entire heat of the exhaust air, i.e., both the thermal heat and the heat contained in the residual coal dust of the exhaust air is recovered in contrast to the indirect firing. ~oreover a coal filter is no longer required because of the combustion of the residual coal dust content. This means a substantial saving and an increased operating safety. Furthermore, coal dust is no longer released into the free atmosphere so that the process according to the invention is much easier on the environment than the process known heretofore. Intermediate storage of coal dust is not required either so that the danger of coal dust explosions and fires is substantlally reduced. Of cause the overall capital, 1~7'~i3 maintenance and operating costs are lower.
In contras-t to the direct and semidirect processes the amount of primary air can be ~reely selected. Thus, the flame can be optimized and the amount of primary air can be kept subs~antially lower. This results in savings of fuel which can be as high as approximately 100 kcal per kg of clinker (0.42 GJ
per ton of clinker) for high coal moistures.
~0
By these adjusting means the proportion of primary air can be reduced optionally and the most varied burner nozzles 24 and combinations of firing, for example, with additional fuel 36, can be used without having to take into account the coal moisture content and the conditions at the grinding drying unit.
Thus, for example, particularly at high coal moisture contents a higher proportion of exhaust air is injected into the clinker cooler. The injection procedure is carried out, for 41~3 example, with an existing cooling air blower 16, like that shown in the Figure, or directly into one of the cooling chambers 31, the latter procedure is not shown in the Figure. ~lowever, the injection pr~cedure can also be distributed over several cooling air blowers 16 or it can even be carried out with a separate cooling air feed blower 34 into one or several cooling air chambers 31 or directly into the hot air end of the clinker, cooler 37 via the grate 25, but preferably into the cooling air chambers 31 closest to the hot air end of the clinker coolex.
The thermal heat of the exhaust air from the mill 1, can thus be fully utilized for heating the secondary air. Furthermore, the portion of non-thermal heat still contained in the mill exhaust air in the form of the residual coal dust content is i~nited on passing through the hot clinker layer and further heats the secondary air. The excess exhaust air from the cooler is passed via the exhaust air pipe 32 to the exhaust air dust collector 27, where~the dust is removed. With the aid of both the exhaust air blower 28 and the contrQl valve 29 the exhaust air, as a function of the pressure ln the furnace top, is released into the atmosphere.
In the l~rocess according to the invention the entire heat of the exhaust air, i.e., both the thermal heat and the heat contained in the residual coal dust of the exhaust air is recovered in contrast to the indirect firing. ~oreover a coal filter is no longer required because of the combustion of the residual coal dust content. This means a substantial saving and an increased operating safety. Furthermore, coal dust is no longer released into the free atmosphere so that the process according to the invention is much easier on the environment than the process known heretofore. Intermediate storage of coal dust is not required either so that the danger of coal dust explosions and fires is substantlally reduced. Of cause the overall capital, 1~7'~i3 maintenance and operating costs are lower.
In contras-t to the direct and semidirect processes the amount of primary air can be ~reely selected. Thus, the flame can be optimized and the amount of primary air can be kept subs~antially lower. This results in savings of fuel which can be as high as approximately 100 kcal per kg of clinker (0.42 GJ
per ton of clinker) for high coal moistures.
~0
Claims (12)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A method for using solid fuel to heat a kiln which discharges heated materials to a cooler, comprising: pulverizing the fuel in a mill; pneumatically conveying the pulverized fuel to a separator for separating fuel particles from fuel-dust-laden air; pneumatically conveying the separated fuel particles to the kiln for burning; and conveying at least a portion of the fuel-dust-laden air to the cooler.
2. The method of claim 1, wherein the step of pneu-matically conveying the separated fuel particles to the kiln for burning is accomplished by using a portion of the fuel-dust-laden air as primary air to convey the separated fuel particles to the kiln.
3. The method of claim 2, further comprising the step of using the fuel-dust-laden air conveyed to the cooler as secon-dary air for burning the separated fuel particles.
4. The method of claim 3, wherein the step of pneu-matically conveying at least a portion of the fuel-dust-laden air to the cooler includes the step of injecting said at least a por-tion of the fuel-dust-laden air beneath a support within the cooler for supporting the heated materials.
5. The method of claim 4, further comprising the step of conveying air from the cooler to the mill for drying the fuel.
6. The method of claim 4, further comprising the step of conveying the combustion gasses of the burned fuel particles to the mill for drying the fuel.
7. The method of claim 4, further comprising the step of burning make-up fuel in addition to pulverized solid fuel for heating the kiln.
8. The method of claim 4, 5,or 6, further compri-sing the step of recirculating a portion of the fuel dust-laden air back to the mill.
9. A method for using coal to heat a kiln which dis-charges heated clinkers to a grate in a clinker cooler, comprising:
pulverizing the coal in a coal mill; pneumatically conveying the pulverized coal to a cyclone; separating coal particles from coal-dust-laden air in the cyclone; splitting the coal-dust-laden air leaving the cyclone into at least first and second streams; using the first stream of coal-dust-laden air as primary air to blow the separated coal particles to the kiln for burning; injecting the se-cond stream of coal-dust-laden air into the clinker cooler beneath the grate thereof to burn the suspended coal dust; using the heated air obtained from the previous step as secondary air for burning the separated coal particles; and conveying the combustion gasses from the burned coal particles to the coal mill to dry the coal therein.
pulverizing the coal in a coal mill; pneumatically conveying the pulverized coal to a cyclone; separating coal particles from coal-dust-laden air in the cyclone; splitting the coal-dust-laden air leaving the cyclone into at least first and second streams; using the first stream of coal-dust-laden air as primary air to blow the separated coal particles to the kiln for burning; injecting the se-cond stream of coal-dust-laden air into the clinker cooler beneath the grate thereof to burn the suspended coal dust; using the heated air obtained from the previous step as secondary air for burning the separated coal particles; and conveying the combustion gasses from the burned coal particles to the coal mill to dry the coal therein.
10. The method of claim 9, further comprising the step of conveying heated air from the clinker cooler to the coal mill to dry the coal therein.
11. The method of claim 10, further comprising the step of cleaning the combustion gasses and air from the clinker cooler before conveying them to the coal mill.
12. The method of claim 11, wherein the step of split-ting the coal-dust-laden air leaving the cyclone in-to at least first and second streams comprises splitting the coal-dust-laden air leaving the cyclone into first, second, and third streams, and further comprising the step of recirculating the third stream back to the coal mill.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE2922904A DE2922904C2 (en) | 1979-06-06 | 1979-06-06 | Dust firing for a process furnace, in particular a furnace for the production of cement clinker |
| DEP2922904.7 | 1979-06-06 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1127463A true CA1127463A (en) | 1982-07-13 |
Family
ID=6072584
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA353,351A Expired CA1127463A (en) | 1979-06-06 | 1980-06-04 | Combination of a coal grinding drying process and a coal heating process with increased heat recovery |
Country Status (9)
| Country | Link |
|---|---|
| JP (1) | JPS581324B2 (en) |
| CA (1) | CA1127463A (en) |
| CH (1) | CH642733A5 (en) |
| DE (1) | DE2922904C2 (en) |
| DK (1) | DK148454C (en) |
| FR (1) | FR2458753A1 (en) |
| GB (1) | GB2050584B (en) |
| IT (1) | IT1140660B (en) |
| SE (1) | SE443040B (en) |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5673556A (en) * | 1979-11-22 | 1981-06-18 | Ube Industries | Coal pulverizer utilizing kiln exhaust gas |
| US4500286A (en) * | 1982-07-29 | 1985-02-19 | Nippon Furnace Kogyo Co., Ltd. | Primary air supply unit of rotary kiln |
| JPS61118414U (en) * | 1985-01-11 | 1986-07-26 | ||
| GB2177189B (en) * | 1985-06-28 | 1989-04-26 | Smidth & Co As F L | Method and cooler for cooling granular material |
| JPH0353110U (en) * | 1989-09-28 | 1991-05-23 | ||
| DE102006012301A1 (en) * | 2006-03-15 | 2007-09-20 | Cemag-Anlagenbau-Dessau Gmbh | Production of cement clinker |
| CN109967217A (en) * | 2019-03-28 | 2019-07-05 | 中国华能集团清洁能源技术研究院有限公司 | A kind of axial separation device and its separation method for medium-speed pulverizer |
| CN113200694A (en) * | 2021-05-26 | 2021-08-03 | 河南省豫鹤同力水泥有限公司 | Production process for reducing coal dilution and clinker heat consumption and improving coal powder heat value |
-
1979
- 1979-06-06 DE DE2922904A patent/DE2922904C2/en not_active Expired
-
1980
- 1980-02-19 FR FR8003567A patent/FR2458753A1/en active Granted
- 1980-02-20 IT IT20051/80A patent/IT1140660B/en active
- 1980-02-28 JP JP55025180A patent/JPS581324B2/en not_active Expired
- 1980-03-14 GB GB8008812A patent/GB2050584B/en not_active Expired
- 1980-04-14 CH CH283980A patent/CH642733A5/en not_active IP Right Cessation
- 1980-05-08 SE SE8003445A patent/SE443040B/en not_active IP Right Cessation
- 1980-06-04 DK DK240380A patent/DK148454C/en not_active IP Right Cessation
- 1980-06-04 CA CA353,351A patent/CA1127463A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| JPS55162528A (en) | 1980-12-17 |
| IT8020051A0 (en) | 1980-02-20 |
| GB2050584A (en) | 1981-01-07 |
| DE2922904C2 (en) | 1983-09-08 |
| DK240380A (en) | 1980-12-07 |
| FR2458753A1 (en) | 1981-01-02 |
| GB2050584B (en) | 1983-11-16 |
| IT1140660B (en) | 1986-10-01 |
| CH642733A5 (en) | 1984-04-30 |
| JPS581324B2 (en) | 1983-01-11 |
| SE443040B (en) | 1986-02-10 |
| DK148454C (en) | 1985-11-25 |
| DE2922904A1 (en) | 1980-12-11 |
| FR2458753B1 (en) | 1984-11-16 |
| DK148454B (en) | 1985-07-08 |
| SE8003445L (en) | 1980-12-07 |
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