CA1055872A - Coal heater temperature control - Google Patents
Coal heater temperature controlInfo
- Publication number
- CA1055872A CA1055872A CA232,062A CA232062A CA1055872A CA 1055872 A CA1055872 A CA 1055872A CA 232062 A CA232062 A CA 232062A CA 1055872 A CA1055872 A CA 1055872A
- Authority
- CA
- Canada
- Prior art keywords
- heat
- equipment
- coal
- heating
- heating equipment
- 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
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10B—DESTRUCTIVE DISTILLATION OF CARBONACEOUS MATERIALS FOR PRODUCTION OF GAS, COKE, TAR, OR SIMILAR MATERIALS
- C10B31/00—Charging devices
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10B—DESTRUCTIVE DISTILLATION OF CARBONACEOUS MATERIALS FOR PRODUCTION OF GAS, COKE, TAR, OR SIMILAR MATERIALS
- C10B57/00—Other carbonising or coking processes; Features of destructive distillation processes in general
- C10B57/08—Non-mechanical pretreatment of the charge, e.g. desulfurization
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F26—DRYING
- F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
- F26B17/00—Machines or apparatus for drying materials in loose, plastic, or fluidised form, e.g. granules, staple fibres, with progressive movement
- F26B17/10—Machines or apparatus for drying materials in loose, plastic, or fluidised form, e.g. granules, staple fibres, with progressive movement with movement performed by fluid currents, e.g. issuing from a nozzle, e.g. pneumatic, flash, vortex or entrainment dryers
- F26B17/101—Machines or apparatus for drying materials in loose, plastic, or fluidised form, e.g. granules, staple fibres, with progressive movement with movement performed by fluid currents, e.g. issuing from a nozzle, e.g. pneumatic, flash, vortex or entrainment dryers the drying enclosure having the shape of one or a plurality of shafts or ducts, e.g. with substantially straight and vertical axis
- F26B17/102—Machines or apparatus for drying materials in loose, plastic, or fluidised form, e.g. granules, staple fibres, with progressive movement with movement performed by fluid currents, e.g. issuing from a nozzle, e.g. pneumatic, flash, vortex or entrainment dryers the drying enclosure having the shape of one or a plurality of shafts or ducts, e.g. with substantially straight and vertical axis with material recirculation, classifying or disintegrating means
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F26—DRYING
- F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
- F26B3/00—Drying solid materials or objects by processes involving the application of heat
- F26B3/02—Drying solid materials or objects by processes involving the application of heat by convection, i.e. heat being conveyed from a heat source to the materials or objects to be dried by a gas or vapour, e.g. air
- F26B3/06—Drying solid materials or objects by processes involving the application of heat by convection, i.e. heat being conveyed from a heat source to the materials or objects to be dried by a gas or vapour, e.g. air the gas or vapour flowing through the materials or objects to be dried
- F26B3/08—Drying solid materials or objects by processes involving the application of heat by convection, i.e. heat being conveyed from a heat source to the materials or objects to be dried by a gas or vapour, e.g. air the gas or vapour flowing through the materials or objects to be dried so as to loosen them, e.g. to form a fluidised bed
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Organic Chemistry (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Life Sciences & Earth Sciences (AREA)
- Microbiology (AREA)
- Solid Fuels And Fuel-Associated Substances (AREA)
- Drying Of Solid Materials (AREA)
- Coke Industry (AREA)
- Control Of Combustion (AREA)
- Control Of Steam Boilers And Waste-Gas Boilers (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
The invention is a method for maintaining heating equipment for coal in standby condition at a desired level of temperature in the heating equipment, during routine interruption of the coal feed. The method includes: monitoring the tempera-ture in the heating equipment; providing an artificial heat load to the heating equipment; causing the artificial heat load to absorb substantially all of the heat, normally absorbed by the coal feed, from a heat source to cause the heat source to operate in its normal range of operation during routine inter-ruption of the coal feed; maintaining the heat output from the heat source at a heat output level during interruption of coal feed which is within its normal range of heat output when coal feed is being supplied; and controlling the amount of the arti-ficial heat load being provided at a level which will absorb sufficient heat in the heating equipment to maintain the tempera-ture in the heating equipment at a desired level.
The invention is a method for maintaining heating equipment for coal in standby condition at a desired level of temperature in the heating equipment, during routine interruption of the coal feed. The method includes: monitoring the tempera-ture in the heating equipment; providing an artificial heat load to the heating equipment; causing the artificial heat load to absorb substantially all of the heat, normally absorbed by the coal feed, from a heat source to cause the heat source to operate in its normal range of operation during routine inter-ruption of the coal feed; maintaining the heat output from the heat source at a heat output level during interruption of coal feed which is within its normal range of heat output when coal feed is being supplied; and controlling the amount of the arti-ficial heat load being provided at a level which will absorb sufficient heat in the heating equipment to maintain the tempera-ture in the heating equipment at a desired level.
Description
5S~'7~
COAL ~IEATER TEMPERATURE CONTROL
Back~round of the Invention This invention relates to industrial processes which call for the heating of coal, or the heating and drying of coal, to temperatures above 100C~ or 212F. More particularly, this invention relates to a method for maintaining heating equipment for coal in standby operating condition, at a desired operating temperature in the heating equipment, during routine interrup-tions in the supply of coal.
As an example, this invention has been adapted for use in a system ~nown as the "Pipeline Charging System". The Pipeline Charging System relates to heating (also known as "preheating") granular coal and conveyance of the coal (also known as "pre-heated coal"), as particles, through a pipeline to coke ovens for the conversion o the coal partiales into coke, rather than conveying the coal to the coke ovens by means of a coal charging car or larry car. In this example, the heating equipment for the coal is known as a "coal preheater" or as "preheating equipment".
Patents which relate generally to the Pipeline Charging System or various aspects of the ~ystem include the following U.S.
Patents: 3,512,723 to J. A. Geoffroy; and 3,523,065 and 3,457,141;
both to L. D. Schmidt.
In the example of a Pipeline Charging System, large quantities of heat are supplied to preheating equipment for the purpose of heating the coal, thereby producing preheated coal, prior to conveying the coal through the pipeline. It is de~ir-able to provide a method for maintaining ~he temperature of the various parts of the preheating equi~pment at a desired level of temperature at times when the supply of coal being fed to the preheating equipment is interrupted.
The supply of coal being fed to the preheating equipment may be interrupted for any one of the number of reasons during _I~ ~ '.
.. .. . .
SS~7~
operation of a coke plant. For example, any plant breakdown that delays the removal of the coke from the coke ovens may require interruption of the coal being fed ~o the preheating equipment. A malfunction in the preheating equipment or pipeline charging equipment may require interruption of the coal being supplied to the heating equipment. The normal effects of changes in personnel between the various shifts in the 2~ hour operation of a coke plant may require interruption of the coal supply.
It is desirable to avoid the necessity of stopping the supply of heat to the preheating equipment or of greatly reducing the supply of heat, which would cool the preheating equipment to a temperature below the normal range of operating temperatures o the heating equipment and probably cause the oxygen content in the atmosphere in the heating equipment to rise. Such cooling is undesirable because when operation is resumed, the preheating equipment will then have to be brought up to the desired tempera-ture again and-down to the desired oxygen content. Instead, it is desirable to have a method of maintaining the heating e~uip-ment at the desired temperature during interruptions of coal feed and maintaining the heat source in a standby operating condition which keeps it in its normal range of operation with reference to heat output and combustion characteristics during interruptions of coal feed.
An emergency system is already known and used for pre-venting the temperature of the preheating equipment from rising to a dangerously high level during such interruptions of the coal feed in order to avoid damage to the equipment and possible formation of explosive mixtures. This prior art emergency system includes the injection of water automatically into the preheating equipment to absorb the heat. However, this emergency system -causes substantially complete shutdown of the preheating equipment and does not maintain the heat output from a heat source in the ~2--. . . .
~ ~5~7~2 heating equipment at a heat output level during interruption of coal feed which is within its normal range of heat output when coal feed is being supplied. Thus, this emexgency syetem does not provide an~ method by which the temperature in the preheating equipment may be controlled in order to maintain the preheating equipment in standby operating condition, that i5, at the desired level of temperature, during routine interruption of the coal feed.
Summary of the Invention The invention is a method for maintaining heating equip-ment for coal in standby condition at a desired level of tempera-ture in the preheating equipment, during routine interruption of the coal feed. The method includes: monitoring the temperature in the preheating equipment; providing an artificial heat load to the preheating equipment; causing the artificial heat load ~o absorb substantially all of the heat, normally absorbed by the coal feed, from a heat source to cause the heat source to operate in its normal range of operation during routine interruption of the coal feed; maintaining the heat output from the heat source at a heat output level during interruption of coal feed which is within its normal range of heat output when coal feed is being supplied; and controlling the amount of the artificial heat load being provided at a level which wlll ab~orb sufficient heat in the heating equipment to maintain the temperature in the heating equipment at a desixed level.
The method further includes: adjusting the heat output from the heat source to a heat~level which is in the lower portion ^
of the normal range of heat output from the heat source. The method further includes: selecting a location in the heating equipment at which the artificial heat load is provided. The step of selecting such a location includes: selecting a point in the heating equipment between the source of heat and the equipment ~: ~ ......
~5~ ~7~
which the coal feed normally contacts.
The step of providing an artificial heat load includes;
injecting a supply of a fluid, pre~erably a liquid, such as water, as the artificial load into the heating equipment.
The step of injecting a supply of fluid includes pro-viding a pipeline through which the liquid is supplied to the heating equipment. The step of controlling the amount of arti-ficial heat load includes: providing a standby control valve for controlling the supply of artificial heat load -to the heating equipment. The step of controlling the amount of artificial heat load may further include adjusting the flow of liquid to the `
heating equipment to a flow rate which is based upon the normal heat output of the heat source supplying heat to the heating equipment.
The step of monitoring the temperature includes: posi-tioning a temperature sensing element in the heating equipment downstream of the location at which the artificial heat load is provided.
This invention provides a number of significant advan-tages which include the following: First, this invention pro-vides a method for maintaining standby operation o the heating equipment for heating coal without cobling the heating equipment below its normal OPerating temperature. Second, this invention provides a method for testing the heating equipment and asso-ciated equipment, at operating temperatures without supplying coal to the heating equipment. Third, this invention provides for additional safety in the operation of heating equipment and pipeline charging equipment by providing a method for cooling the heating equipment and pipeline charging equipment, in addi-tion to presently available emergency methods. Fourth, this invention provides a method for adjusting the burner of heating equipment to desired combustion conditions without overheating :. .
1~)5~72 part of the equipment when the burner heat output is within its normal range of operation. Fifth, this invention provides a method for improving safety conditions in coal heating equipment and reducing the possibility of explosions by establishing conditions under which any required amount of time may be used in adjusting the heat source, such as a burner, and in ad~usting the oxygen content in the heating equipment to any desired per-centage before coal is introduced in the heating equipment.
Description of the Drawings Fig. 1 i9 a schematic illustration of typical heating equipment as used with pipeline charging equipment in a coke plant, indicating a first embodiment of this invention.
Fig. 2 is a partial schematic illustration of the same heating equipment shown in Fig. 1, but indicating a second embo-diment of this invention.
Fig. 3 is a cros3-sectionaL view of a small portion of the heating equipment shown in Fig. 1. Fig. 3 shows typical apparatus used to provide an artificial heat load to the venturi throat of Fig. l.
Fig. 4 is a block diagram of apparatus used in one embodiment of this invention for controlling the flow of artifi-cial heat load.
Detailed Description This invention relates to a method for maintaining heating equipment for coal in a standby condition at a desired level of temperature in the heating equipment. The heating equipment is intended to heat the coal, or heat and dry the coal, to temperatures above 100C. or 212F. The method will be described in reference to a Pipeline Charging System in which the heating equipment is hereinafter called "preheating equipmentl'.
The coal is heated (hereinafter called "preheated coal") and then conveyed by pipeline charging to coke ovens. However, the method ~)5~72 of this invention may be used with other heating equipment for coal, other than the Pipeline Charging System.
Referring to Figs. l and 2, partially crushed, wet coal is supplied to a feed hopper 2, then to twin screw feeders 4, then to a flash drying chamber 6 above a ventuxi throat 8. A
fuel (such as a coke oven gas) and air are supplied to a burner 10 of a combustion chamber 12 for combustion therein, producing hot flue gases. A temperature sensing unit 3 signals a tempera-ture control unit S to adjust the flow of fuel through valve 7 to burner lO to that required to maintain the temperature at the temperature sensing unit 3 at a preselected level which normally is within the range o temperakures from 500F. to 575F. (260C.
to 300C.). A graup of sensing units (not shown) and controls (not shown) automatically adju~t the air input to burner 10 proportionately to the ~uel input to burner lO. Thus, the heat output of burner lO is adjusted to produce the desired temperature in the preheating equipment, as sensed by temperature sensing unit 3. The flue gases from the combustion chamber 12 travel up through the venturi throat 8 and contact the coal in the flash drying chamber 6. The hot flue gases heat the coal and evaporate a substantial part of the surface moisture on the coal, thereby producing partially dried, preheated coal. The partially dried coal moves up through a crush-disperser 14, rotating in a dilute fluid bed in which the coal is further dried and heated, then through an elutriation zone 16 and then through a coal duct 18 which leads to a set of cyclones 20. The coal then moves through a rotary feeder 22 and/or feeder pipes 23 to a distribution hopper 25, then to charge bin~ 26, then to pipelines 28 which c~nvey the coal, mixed with superheated steam, to coke ovens.
The method of this invention relates to the preheating equipment, referred to generally by the numeral 29. The pre-heating equipment 29 includes: the combustion chamber 12, burner .
~ 1l)551 372 l, venturi throat 8, flash drying chamber 6, crusher-disperser 14, elutriation zone 16, coal duct 18, and cyclones 20, among other equipment. More particularly, the method of this invention ..
relates to maintenance of the preheating equipment in standby operating condition, at a desired operating temperature in the preheating equipment, during routine interruptions in the supply of coal through screw feeders 4.
The method includes: monitoring the temperature in the preheating equipment 29; providing an artificial heat load to the preheating equipment 29; causing the artifical heat load to absorb substantially all of the heat from the heat source, such as burner 10, normally absorbed by the coal prior to interruption of the coal feed, to cause the heat source to operate in its normal range o~ operation; maintaining the heat output from the heat source at a heat output level during interruption of coal feed which is within its normal range of heat output when coal feed is being supplied; and controlling the amount of the artifi-cial heat load being provided at a level which will absorb suffi- ;~
cient heat in the preheating equipment 29 to maintain the tempera-ture in the preheating equipment at a desired level. In the embodiments of Figs. 1 and 2, the heat source is a burner 10 which is part of combustion chamber 12.
The method further includes adjusting the heat output from the heat source to a heat output level which is in the lower portion of the normal range of heat output from the heat source when the coal is being supplied to the preheating e~uipment, prior to interruption of the coal feed. In this embodiment, the heat output from the heat source is in the range of from 20 million BTU's per hour to 125 million BTU's per hour. As a first example, for a unit rated at a nominal input of about ~0 U.S. tons of coal per hour, the heat source may have a heat output capacity of about 20 million BTU's per hour. As a second example) for a ,,~' SSi~7~
unit rated at a nominal input of about 100 ~.S. tons of coal per hour, the heat source may have a heat output capacity of about 75 million BTU's per hour. As a third example, for a unit rated at a nominal input of about 150 U.S. tons of coal per hour, the heat source may have a heat output capacity of about 125 million BTU's per hour. Preferably, in the first example for a 40 U.S.
ton per hour unit, the artificial heat load is adjusted to require a heat output level fxom the heat source of approximately 5 million BTU's per hour during interruption oE coal feed. Prefer-ably, in the second example for a 100 U.S. ton per hour unit, the artificial heat load is adjusted to require a heat ou~put level from the heat source of approximately 20 million BTU's per hour during interruption of coal feed. Preferably, in the third example for a 150 U.S. ton per hour unit, the artificial heat load is adjusted to require a heat output level from the heat source of approximately 30 million BTU's per hour during interruption of the coal feed. Since the heat source is still fully in operation within its normal range of heat output during interruption of coal feed, operation of the preheating equipment can easily and conveniently be resumed, without delay in bringing the heat source back into operation.
The method ~urther includes selectiny a location in the preheating equipment 29 at which the artificial heat load is provided. The step o selecting such a location in the preheating equipment 29 includes selecting any convenient location in the preheating equipment 29 between the source of heat and the equip-ment which the coal feed normally contacts prior to interruption.
For example, the artificial heat load may be provided at the venturi throat 8 in a first embodiment of this invention as illus-trated in Fig. 1. In the alternative, the artificial heat load may be provided at the flash drying chamber 6 in a second embodi-ment of this invention as illustrated in Fig. 2. In the alternative, )5~7~Z
the artificial heat load may be provided at a location immediately under, that is, upstream of the crusher-disperser 14.
The step of providing an artificial load includes injecting a supply of a fluid, preferably a liquid, such as water, as the artificial load, into the preheating equipment. The step of injecting a supply of water includes providing a pipeline 30 through which a flow of water is supplied to the preheating equipment 29. The step of monitoring the temperature includes positioning a temperature sensing element 24 in the prehelting equipment 29 downstream of the location selected for providing the artificial heat load. In a first embodiment, the temperature sensing element 24 may be positioned in the preheating equipmeht 29 downstream of the crusher-disperser 14, such as in the elutria-tion zone 16, as illustrated in Fig. 1. In the alternative, in a second embodiment the temperature sensing element 2~ may be posi-tioned in the coal duct 18 of the preheating equipment 29 down-stream from the elutriation zone 16 of the preheating equipment, as illustrated in Fig. 2. The elutriation zone 16 is located above the crusher-disperser 14. The function of the elutriation zone 16 is to separate larger particles in the coal stream.
An emergency system is already known and used or pre-venting the temperature of the preheating equipment 29 from rising to a dangerously high level during interruptions of the coal feed. This emergency system operates automatically and uses a water supply pipeline 30. The same water supply pipeline may also be used for the method of this invention. The emergency system uses a valve 32 positioned in the water supply pipeline and the same valve may also be used for the method of this inven-tion. An additional flow control valve 32, not presently used for the emergency system, may be provided for controlling the flow of water through the valve during non-emergency conditions.
The emergency system also uses a temperature sensing element or _9_ . . . . .
1~35~
a series of temperature sensing elements. Preferably/ a separate, additional temperature sensing element 24 may be used for the - method of this invention.
In the embodiment illustrated in Fig. 1, where the location selected for providing the artificial load is the venturi throat 8, Fig. 3 illustrates a typical apparatus which may be used for injecting the artificial heat load, such a~ water into the venturi throat 8. A plurality of conduits 36, such as pipes, are provided to conduct the artificial heat load into the venturi ~10 throat 8. In this example, four such conduits 36 are provided.
In other embodiments, a greater or lesser number of conduits may be used. Preferably, each conduit 36 is arranged at an angle 38 with the horizontal of approximately 45. Preferably, a nozzle 40 is provided at the interior end of each conduit 36 within the venturi throat 8 for the purpose of projecting the artificial heat load across the high velocity flow of hot flue gases passing through the venturi throat 8. Spray nozzles 40 forming a cone pattern of approximately 45 are preferred. In the alternative, the artificial heat load may be projected through conduits 36 without the use of a nozzle, if a sufficient number of conduits are used ~uch that the maximum injection rate is no more than five gallons per minute per conduit 36.
Apparatus similar to that illustrated in Fig. 3 may be used to inject the artificial heat load into the flash drying chamber 6, according to the embodiment illustrated in Fig. 2, or into other parts of preheating equipment. Water pipes of 1/2 inch diameter have been found to work well in supplying water to the preheating equipment. Referring to Fig. 3, each of the conduits 36 may preferably be provided with a purging means 42 for purging the conduits 36 of dust, such as by use of air~when the conduits 36 are not in use. Optionally, each of the conduits 36 may also be provided with a convenience valve 46.
.
:, ' , , .. . .
S~7Z
The step of providing a supply of artificial heat load, such as water, may be accomplished in two ways: a simplified arrangement; or a more sophisticated arrangement. Referring to Figs. 1 and 2, in the simplified arrangement, a si~ple, on-off, flow valve 32 is used. A predetermined flow of artificial heat load is provided from a supply of artificial heat load 44 which provides fixed, metered flow at a predetermined flow rate. A
temperature switch (TS~ 35 operates a flow control 34 to turn the supply of water on and off by means of flow valve 32 automa-tically according to the temperature in the preheating equipment 29 or manually at the discretion of the operator.
Referring to Fig. 4, the more sophisticated arrangement permits an operator to adjust the flow of artificial heat load to the preheating equipment based upon the heat output o the heat source supplying heat to the preheating equipment 29. For example, ; the more sophisticated arrangement permits an operator to use a reduced flow of artificial heat load during warm-up of the equipment. It also permits an operator to adjust the artificial heat load over the entire operating range of heat source capacity should this be desired for any reason, such as for checking uni-formity of combustion at various operating rates. The more sophisticated method uses the temperature sensing element 24, a temperature indicating and control unit 48, a flow rate indicating and control unit 50, an adjustable flow control valve 52, and a flow rate sensing unit 54. The flow rate sensing unit 54 senses the flow of artificial heat load. The flow of artificial heat load is adjustable by means of the adjustable flow control valve 52. The flow rate sensing unit 54 transmits a si~nal to the flow rate indicating and control unit 50. As a result, the flow rate indicating and control unit 50 adjusts the flow control valve 52 to the desired flow rate of artificial heat load. The temperature sensing element 24 senses the temperature in the :: -. :
~ os~ z~reheating equipment and the temperature condition is registered in the temperature indicating and control unit 48.
In both the simplified method and the more sophisti-cated method, the temperature sensing element may be a thermo-couple means. In general, the flow rate should be in the range of 5 to 100 gallons per minute.
Preferably, the flow rate of the artificial heat load should provide a heat load of about 20~ to 50~ of the normal heat output capacity of the heat source, such as the burner 10, of the preheating equipment 29. The desired flow rate may be established as follows. Assume that the capacity of the heat source is 60 million BTU/hr, for example. The desired flow rate is one which will use 20 to 30 million BTU's/hour, preferably 25 million BT~'s/hour. In the example where the artificial heat load is water, the water is evaporated and the resultant steam is super-heated to about 500F. at about atmospheric pressure. (Coal drying and preheating equipment usually is operated at about at-mospheric pressure.~ For such conditions, each pound of water requires about 1250 BTU, and the water requirement is, therefore:
25~250 = 20,000 lbs/hr (+20%) which is about 40 gallons per minute (+20~).
Most of the water injected into the preheating equipment 29 evaporates before it reaches the elutriation zone 16. By keeping the heat source, such as burner 10, within its normal range of operation, the atmosphere within the preheating equip-:.
ment 29 will be main~ained in a safe, non-explosive condition.
Controlling the atmosphere in the preheating equipment ` 29 also prevents detrimental oxidation of the coal being preheated by maintaining a low oxygen concentration. Keeping the oxygen content below 5% eliminates the possibility of explosions from all possible sources. The oxygen content is normally held below 1~ to minimize possible damage to the coking properties of the ' ~''` .
:, .
-~. . , . . , . .. . , ,. ~ .... :
COAL ~IEATER TEMPERATURE CONTROL
Back~round of the Invention This invention relates to industrial processes which call for the heating of coal, or the heating and drying of coal, to temperatures above 100C~ or 212F. More particularly, this invention relates to a method for maintaining heating equipment for coal in standby operating condition, at a desired operating temperature in the heating equipment, during routine interrup-tions in the supply of coal.
As an example, this invention has been adapted for use in a system ~nown as the "Pipeline Charging System". The Pipeline Charging System relates to heating (also known as "preheating") granular coal and conveyance of the coal (also known as "pre-heated coal"), as particles, through a pipeline to coke ovens for the conversion o the coal partiales into coke, rather than conveying the coal to the coke ovens by means of a coal charging car or larry car. In this example, the heating equipment for the coal is known as a "coal preheater" or as "preheating equipment".
Patents which relate generally to the Pipeline Charging System or various aspects of the ~ystem include the following U.S.
Patents: 3,512,723 to J. A. Geoffroy; and 3,523,065 and 3,457,141;
both to L. D. Schmidt.
In the example of a Pipeline Charging System, large quantities of heat are supplied to preheating equipment for the purpose of heating the coal, thereby producing preheated coal, prior to conveying the coal through the pipeline. It is de~ir-able to provide a method for maintaining ~he temperature of the various parts of the preheating equi~pment at a desired level of temperature at times when the supply of coal being fed to the preheating equipment is interrupted.
The supply of coal being fed to the preheating equipment may be interrupted for any one of the number of reasons during _I~ ~ '.
.. .. . .
SS~7~
operation of a coke plant. For example, any plant breakdown that delays the removal of the coke from the coke ovens may require interruption of the coal being fed ~o the preheating equipment. A malfunction in the preheating equipment or pipeline charging equipment may require interruption of the coal being supplied to the heating equipment. The normal effects of changes in personnel between the various shifts in the 2~ hour operation of a coke plant may require interruption of the coal supply.
It is desirable to avoid the necessity of stopping the supply of heat to the preheating equipment or of greatly reducing the supply of heat, which would cool the preheating equipment to a temperature below the normal range of operating temperatures o the heating equipment and probably cause the oxygen content in the atmosphere in the heating equipment to rise. Such cooling is undesirable because when operation is resumed, the preheating equipment will then have to be brought up to the desired tempera-ture again and-down to the desired oxygen content. Instead, it is desirable to have a method of maintaining the heating e~uip-ment at the desired temperature during interruptions of coal feed and maintaining the heat source in a standby operating condition which keeps it in its normal range of operation with reference to heat output and combustion characteristics during interruptions of coal feed.
An emergency system is already known and used for pre-venting the temperature of the preheating equipment from rising to a dangerously high level during such interruptions of the coal feed in order to avoid damage to the equipment and possible formation of explosive mixtures. This prior art emergency system includes the injection of water automatically into the preheating equipment to absorb the heat. However, this emergency system -causes substantially complete shutdown of the preheating equipment and does not maintain the heat output from a heat source in the ~2--. . . .
~ ~5~7~2 heating equipment at a heat output level during interruption of coal feed which is within its normal range of heat output when coal feed is being supplied. Thus, this emexgency syetem does not provide an~ method by which the temperature in the preheating equipment may be controlled in order to maintain the preheating equipment in standby operating condition, that i5, at the desired level of temperature, during routine interruption of the coal feed.
Summary of the Invention The invention is a method for maintaining heating equip-ment for coal in standby condition at a desired level of tempera-ture in the preheating equipment, during routine interruption of the coal feed. The method includes: monitoring the temperature in the preheating equipment; providing an artificial heat load to the preheating equipment; causing the artificial heat load ~o absorb substantially all of the heat, normally absorbed by the coal feed, from a heat source to cause the heat source to operate in its normal range of operation during routine interruption of the coal feed; maintaining the heat output from the heat source at a heat output level during interruption of coal feed which is within its normal range of heat output when coal feed is being supplied; and controlling the amount of the artificial heat load being provided at a level which wlll ab~orb sufficient heat in the heating equipment to maintain the temperature in the heating equipment at a desixed level.
The method further includes: adjusting the heat output from the heat source to a heat~level which is in the lower portion ^
of the normal range of heat output from the heat source. The method further includes: selecting a location in the heating equipment at which the artificial heat load is provided. The step of selecting such a location includes: selecting a point in the heating equipment between the source of heat and the equipment ~: ~ ......
~5~ ~7~
which the coal feed normally contacts.
The step of providing an artificial heat load includes;
injecting a supply of a fluid, pre~erably a liquid, such as water, as the artificial load into the heating equipment.
The step of injecting a supply of fluid includes pro-viding a pipeline through which the liquid is supplied to the heating equipment. The step of controlling the amount of arti-ficial heat load includes: providing a standby control valve for controlling the supply of artificial heat load -to the heating equipment. The step of controlling the amount of artificial heat load may further include adjusting the flow of liquid to the `
heating equipment to a flow rate which is based upon the normal heat output of the heat source supplying heat to the heating equipment.
The step of monitoring the temperature includes: posi-tioning a temperature sensing element in the heating equipment downstream of the location at which the artificial heat load is provided.
This invention provides a number of significant advan-tages which include the following: First, this invention pro-vides a method for maintaining standby operation o the heating equipment for heating coal without cobling the heating equipment below its normal OPerating temperature. Second, this invention provides a method for testing the heating equipment and asso-ciated equipment, at operating temperatures without supplying coal to the heating equipment. Third, this invention provides for additional safety in the operation of heating equipment and pipeline charging equipment by providing a method for cooling the heating equipment and pipeline charging equipment, in addi-tion to presently available emergency methods. Fourth, this invention provides a method for adjusting the burner of heating equipment to desired combustion conditions without overheating :. .
1~)5~72 part of the equipment when the burner heat output is within its normal range of operation. Fifth, this invention provides a method for improving safety conditions in coal heating equipment and reducing the possibility of explosions by establishing conditions under which any required amount of time may be used in adjusting the heat source, such as a burner, and in ad~usting the oxygen content in the heating equipment to any desired per-centage before coal is introduced in the heating equipment.
Description of the Drawings Fig. 1 i9 a schematic illustration of typical heating equipment as used with pipeline charging equipment in a coke plant, indicating a first embodiment of this invention.
Fig. 2 is a partial schematic illustration of the same heating equipment shown in Fig. 1, but indicating a second embo-diment of this invention.
Fig. 3 is a cros3-sectionaL view of a small portion of the heating equipment shown in Fig. 1. Fig. 3 shows typical apparatus used to provide an artificial heat load to the venturi throat of Fig. l.
Fig. 4 is a block diagram of apparatus used in one embodiment of this invention for controlling the flow of artifi-cial heat load.
Detailed Description This invention relates to a method for maintaining heating equipment for coal in a standby condition at a desired level of temperature in the heating equipment. The heating equipment is intended to heat the coal, or heat and dry the coal, to temperatures above 100C. or 212F. The method will be described in reference to a Pipeline Charging System in which the heating equipment is hereinafter called "preheating equipmentl'.
The coal is heated (hereinafter called "preheated coal") and then conveyed by pipeline charging to coke ovens. However, the method ~)5~72 of this invention may be used with other heating equipment for coal, other than the Pipeline Charging System.
Referring to Figs. l and 2, partially crushed, wet coal is supplied to a feed hopper 2, then to twin screw feeders 4, then to a flash drying chamber 6 above a ventuxi throat 8. A
fuel (such as a coke oven gas) and air are supplied to a burner 10 of a combustion chamber 12 for combustion therein, producing hot flue gases. A temperature sensing unit 3 signals a tempera-ture control unit S to adjust the flow of fuel through valve 7 to burner lO to that required to maintain the temperature at the temperature sensing unit 3 at a preselected level which normally is within the range o temperakures from 500F. to 575F. (260C.
to 300C.). A graup of sensing units (not shown) and controls (not shown) automatically adju~t the air input to burner 10 proportionately to the ~uel input to burner lO. Thus, the heat output of burner lO is adjusted to produce the desired temperature in the preheating equipment, as sensed by temperature sensing unit 3. The flue gases from the combustion chamber 12 travel up through the venturi throat 8 and contact the coal in the flash drying chamber 6. The hot flue gases heat the coal and evaporate a substantial part of the surface moisture on the coal, thereby producing partially dried, preheated coal. The partially dried coal moves up through a crush-disperser 14, rotating in a dilute fluid bed in which the coal is further dried and heated, then through an elutriation zone 16 and then through a coal duct 18 which leads to a set of cyclones 20. The coal then moves through a rotary feeder 22 and/or feeder pipes 23 to a distribution hopper 25, then to charge bin~ 26, then to pipelines 28 which c~nvey the coal, mixed with superheated steam, to coke ovens.
The method of this invention relates to the preheating equipment, referred to generally by the numeral 29. The pre-heating equipment 29 includes: the combustion chamber 12, burner .
~ 1l)551 372 l, venturi throat 8, flash drying chamber 6, crusher-disperser 14, elutriation zone 16, coal duct 18, and cyclones 20, among other equipment. More particularly, the method of this invention ..
relates to maintenance of the preheating equipment in standby operating condition, at a desired operating temperature in the preheating equipment, during routine interruptions in the supply of coal through screw feeders 4.
The method includes: monitoring the temperature in the preheating equipment 29; providing an artificial heat load to the preheating equipment 29; causing the artifical heat load to absorb substantially all of the heat from the heat source, such as burner 10, normally absorbed by the coal prior to interruption of the coal feed, to cause the heat source to operate in its normal range o~ operation; maintaining the heat output from the heat source at a heat output level during interruption of coal feed which is within its normal range of heat output when coal feed is being supplied; and controlling the amount of the artifi-cial heat load being provided at a level which will absorb suffi- ;~
cient heat in the preheating equipment 29 to maintain the tempera-ture in the preheating equipment at a desired level. In the embodiments of Figs. 1 and 2, the heat source is a burner 10 which is part of combustion chamber 12.
The method further includes adjusting the heat output from the heat source to a heat output level which is in the lower portion of the normal range of heat output from the heat source when the coal is being supplied to the preheating e~uipment, prior to interruption of the coal feed. In this embodiment, the heat output from the heat source is in the range of from 20 million BTU's per hour to 125 million BTU's per hour. As a first example, for a unit rated at a nominal input of about ~0 U.S. tons of coal per hour, the heat source may have a heat output capacity of about 20 million BTU's per hour. As a second example) for a ,,~' SSi~7~
unit rated at a nominal input of about 100 ~.S. tons of coal per hour, the heat source may have a heat output capacity of about 75 million BTU's per hour. As a third example, for a unit rated at a nominal input of about 150 U.S. tons of coal per hour, the heat source may have a heat output capacity of about 125 million BTU's per hour. Preferably, in the first example for a 40 U.S.
ton per hour unit, the artificial heat load is adjusted to require a heat output level fxom the heat source of approximately 5 million BTU's per hour during interruption oE coal feed. Prefer-ably, in the second example for a 100 U.S. ton per hour unit, the artificial heat load is adjusted to require a heat ou~put level from the heat source of approximately 20 million BTU's per hour during interruption of coal feed. Preferably, in the third example for a 150 U.S. ton per hour unit, the artificial heat load is adjusted to require a heat output level from the heat source of approximately 30 million BTU's per hour during interruption of the coal feed. Since the heat source is still fully in operation within its normal range of heat output during interruption of coal feed, operation of the preheating equipment can easily and conveniently be resumed, without delay in bringing the heat source back into operation.
The method ~urther includes selectiny a location in the preheating equipment 29 at which the artificial heat load is provided. The step o selecting such a location in the preheating equipment 29 includes selecting any convenient location in the preheating equipment 29 between the source of heat and the equip-ment which the coal feed normally contacts prior to interruption.
For example, the artificial heat load may be provided at the venturi throat 8 in a first embodiment of this invention as illus-trated in Fig. 1. In the alternative, the artificial heat load may be provided at the flash drying chamber 6 in a second embodi-ment of this invention as illustrated in Fig. 2. In the alternative, )5~7~Z
the artificial heat load may be provided at a location immediately under, that is, upstream of the crusher-disperser 14.
The step of providing an artificial load includes injecting a supply of a fluid, preferably a liquid, such as water, as the artificial load, into the preheating equipment. The step of injecting a supply of water includes providing a pipeline 30 through which a flow of water is supplied to the preheating equipment 29. The step of monitoring the temperature includes positioning a temperature sensing element 24 in the prehelting equipment 29 downstream of the location selected for providing the artificial heat load. In a first embodiment, the temperature sensing element 24 may be positioned in the preheating equipmeht 29 downstream of the crusher-disperser 14, such as in the elutria-tion zone 16, as illustrated in Fig. 1. In the alternative, in a second embodiment the temperature sensing element 2~ may be posi-tioned in the coal duct 18 of the preheating equipment 29 down-stream from the elutriation zone 16 of the preheating equipment, as illustrated in Fig. 2. The elutriation zone 16 is located above the crusher-disperser 14. The function of the elutriation zone 16 is to separate larger particles in the coal stream.
An emergency system is already known and used or pre-venting the temperature of the preheating equipment 29 from rising to a dangerously high level during interruptions of the coal feed. This emergency system operates automatically and uses a water supply pipeline 30. The same water supply pipeline may also be used for the method of this invention. The emergency system uses a valve 32 positioned in the water supply pipeline and the same valve may also be used for the method of this inven-tion. An additional flow control valve 32, not presently used for the emergency system, may be provided for controlling the flow of water through the valve during non-emergency conditions.
The emergency system also uses a temperature sensing element or _9_ . . . . .
1~35~
a series of temperature sensing elements. Preferably/ a separate, additional temperature sensing element 24 may be used for the - method of this invention.
In the embodiment illustrated in Fig. 1, where the location selected for providing the artificial load is the venturi throat 8, Fig. 3 illustrates a typical apparatus which may be used for injecting the artificial heat load, such a~ water into the venturi throat 8. A plurality of conduits 36, such as pipes, are provided to conduct the artificial heat load into the venturi ~10 throat 8. In this example, four such conduits 36 are provided.
In other embodiments, a greater or lesser number of conduits may be used. Preferably, each conduit 36 is arranged at an angle 38 with the horizontal of approximately 45. Preferably, a nozzle 40 is provided at the interior end of each conduit 36 within the venturi throat 8 for the purpose of projecting the artificial heat load across the high velocity flow of hot flue gases passing through the venturi throat 8. Spray nozzles 40 forming a cone pattern of approximately 45 are preferred. In the alternative, the artificial heat load may be projected through conduits 36 without the use of a nozzle, if a sufficient number of conduits are used ~uch that the maximum injection rate is no more than five gallons per minute per conduit 36.
Apparatus similar to that illustrated in Fig. 3 may be used to inject the artificial heat load into the flash drying chamber 6, according to the embodiment illustrated in Fig. 2, or into other parts of preheating equipment. Water pipes of 1/2 inch diameter have been found to work well in supplying water to the preheating equipment. Referring to Fig. 3, each of the conduits 36 may preferably be provided with a purging means 42 for purging the conduits 36 of dust, such as by use of air~when the conduits 36 are not in use. Optionally, each of the conduits 36 may also be provided with a convenience valve 46.
.
:, ' , , .. . .
S~7Z
The step of providing a supply of artificial heat load, such as water, may be accomplished in two ways: a simplified arrangement; or a more sophisticated arrangement. Referring to Figs. 1 and 2, in the simplified arrangement, a si~ple, on-off, flow valve 32 is used. A predetermined flow of artificial heat load is provided from a supply of artificial heat load 44 which provides fixed, metered flow at a predetermined flow rate. A
temperature switch (TS~ 35 operates a flow control 34 to turn the supply of water on and off by means of flow valve 32 automa-tically according to the temperature in the preheating equipment 29 or manually at the discretion of the operator.
Referring to Fig. 4, the more sophisticated arrangement permits an operator to adjust the flow of artificial heat load to the preheating equipment based upon the heat output o the heat source supplying heat to the preheating equipment 29. For example, ; the more sophisticated arrangement permits an operator to use a reduced flow of artificial heat load during warm-up of the equipment. It also permits an operator to adjust the artificial heat load over the entire operating range of heat source capacity should this be desired for any reason, such as for checking uni-formity of combustion at various operating rates. The more sophisticated method uses the temperature sensing element 24, a temperature indicating and control unit 48, a flow rate indicating and control unit 50, an adjustable flow control valve 52, and a flow rate sensing unit 54. The flow rate sensing unit 54 senses the flow of artificial heat load. The flow of artificial heat load is adjustable by means of the adjustable flow control valve 52. The flow rate sensing unit 54 transmits a si~nal to the flow rate indicating and control unit 50. As a result, the flow rate indicating and control unit 50 adjusts the flow control valve 52 to the desired flow rate of artificial heat load. The temperature sensing element 24 senses the temperature in the :: -. :
~ os~ z~reheating equipment and the temperature condition is registered in the temperature indicating and control unit 48.
In both the simplified method and the more sophisti-cated method, the temperature sensing element may be a thermo-couple means. In general, the flow rate should be in the range of 5 to 100 gallons per minute.
Preferably, the flow rate of the artificial heat load should provide a heat load of about 20~ to 50~ of the normal heat output capacity of the heat source, such as the burner 10, of the preheating equipment 29. The desired flow rate may be established as follows. Assume that the capacity of the heat source is 60 million BTU/hr, for example. The desired flow rate is one which will use 20 to 30 million BTU's/hour, preferably 25 million BT~'s/hour. In the example where the artificial heat load is water, the water is evaporated and the resultant steam is super-heated to about 500F. at about atmospheric pressure. (Coal drying and preheating equipment usually is operated at about at-mospheric pressure.~ For such conditions, each pound of water requires about 1250 BTU, and the water requirement is, therefore:
25~250 = 20,000 lbs/hr (+20%) which is about 40 gallons per minute (+20~).
Most of the water injected into the preheating equipment 29 evaporates before it reaches the elutriation zone 16. By keeping the heat source, such as burner 10, within its normal range of operation, the atmosphere within the preheating equip-:.
ment 29 will be main~ained in a safe, non-explosive condition.
Controlling the atmosphere in the preheating equipment ` 29 also prevents detrimental oxidation of the coal being preheated by maintaining a low oxygen concentration. Keeping the oxygen content below 5% eliminates the possibility of explosions from all possible sources. The oxygen content is normally held below 1~ to minimize possible damage to the coking properties of the ' ~''` .
:, .
-~. . , . . , . .. . , ,. ~ .... :
Claims (13)
1. A method for maintaining equipment used for heating coal at a temperature within a temperature range normally used for heating said coal in said equipment, which comprises monitor-ing the temperature in the heating equipment introducing into said equipment a heat-absorbing liquid at a rate sufficient to absorb substantially all of the heat normally absorbed by said coal when fed to such equipment and to maintain said equipment at a tempera-ture within said temperature range maintained for heating said coal in said equipment.
2. The method of Claim 1 wherein the introduction of the heat-absorbing liquid is adjusted during the introduc-tion of coal into said heating equipment to maintain the tem-perature of said coal in said heating equipment at a tempera-ture within said temperature range maintained for heating coal in said equipment.
3. The method of Claim 1 wherein the oxygen content within the heating equipment is below 5%, by volume.
4. The method of Claim 1 wherein the heat-absorbing liquid is an aqueous solution.
5. The method of Claim 1 wherein the heat-absorbing liquid is water.
6. A method for maintaining heating equipment for coal in standby condition, at a desired level of temperature in the heating equipment provided with a heat source, during inter-ruption of the coal feed to said equipment which comprises the steps of monitoring the temperature in the heating equipment, injecting a heat-absorbing liquid into the heating equipment in amounts sufficient to absorb substantially all of the heat from the heat source of the heating equipment normally absorbed by the coal fed to said equipment prior to interrupting of the coal feed and to permit the heat source to operate in its normal range of heat output during injection of the heat-absorbing liquid into said equipment; and maintaining the heat output from the heat source at a heat output level during interruption of coal feed which is within its normal range of heat output as when the coal is being fed to said equipment.
7. The method according to Claim 6 wherein the heat output from the heat source is adjusted to a heat output level during interruption of coal feed which is in the lower portion of the normal range of heat output from the heat source when the coal feed is being supplied.
8. The method according to Claim 6 wherein the heat-absorbing liquid is introduced into the heating equipment be-tween the source of heat and the equipment which the coal feed normally contacts prior to interruption.
9. The method according to Claim 8 wherein said heating equipment includes a venturi throat and the heat-ab-sorbing liquid is injected into said equipment in said venturi throat.
10. The method according to Claim 8 wherein said heating equipment includes a flash drying chamber and the heat-absorbing liquid is injected into said equipment in said flash drying chamber.
11. The method according to Claim 8 wherein said heating equipment includes a crusher-disperser and the heat-absorbing liquid is injected into said equipment at a location immediately upstream of crusher-disperser.
12. The method according to Claim 6 wherein the heat-absorbing liquid is an aqueous solution.
13. The method according to Claim 6 wherein the heat-absorbing liquid is water.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US49815274A | 1974-08-16 | 1974-08-16 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1055872A true CA1055872A (en) | 1979-06-05 |
Family
ID=23979796
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA232,062A Expired CA1055872A (en) | 1974-08-16 | 1975-07-23 | Coal heater temperature control |
Country Status (17)
| Country | Link |
|---|---|
| JP (1) | JPS5146302A (en) |
| AR (1) | AR207472A1 (en) |
| AT (1) | AT362744B (en) |
| BE (1) | BE832162A (en) |
| BR (1) | BR7505230A (en) |
| CA (1) | CA1055872A (en) |
| DE (1) | DE2534383A1 (en) |
| ES (1) | ES439793A1 (en) |
| FR (1) | FR2281971A1 (en) |
| GB (1) | GB1467744A (en) |
| IT (1) | IT1041484B (en) |
| LU (1) | LU73126A1 (en) |
| MX (1) | MX146349A (en) |
| NL (1) | NL7508618A (en) |
| PL (1) | PL97850B1 (en) |
| TR (1) | TR18894A (en) |
| ZA (1) | ZA754754B (en) |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2378081A1 (en) * | 1977-01-24 | 1978-08-18 | Charbonnages De France | INSTALLATION AND METHOD OF REGULATING THE PREHEATING OF COKEFYING COAL |
| DE2750513C2 (en) * | 1977-11-11 | 1979-11-22 | 4300 Essen | Process for the operation of coal heating plants |
| LU91451B1 (en) * | 2008-06-02 | 2009-12-03 | Wurth Paul Sa | Method for producing pulverized coal |
| LU91450B1 (en) * | 2008-06-02 | 2009-12-03 | Wurth Paul Sa | Method for producing pulverized coal |
| US9340741B2 (en) | 2009-09-09 | 2016-05-17 | Gas Technology Institute | Biomass torrefaction mill |
| TR201807234T4 (en) * | 2013-12-12 | 2018-06-21 | Outotec Finland Oy | The method and arrangement for drying the particulate matter and the use of this method or arrangement. |
| CN106196896A (en) * | 2016-06-27 | 2016-12-07 | 安庆市微知著电器有限公司 | A kind of controlling temp type exsiccator |
| CN106885461A (en) * | 2017-03-27 | 2017-06-23 | 内蒙古凯程农牧业科技有限公司 | A kind of drying plant and furnace drying method |
-
1975
- 1975-01-01 AR AR259822A patent/AR207472A1/en active
- 1975-07-18 NL NL7508618A patent/NL7508618A/en not_active Application Discontinuation
- 1975-07-23 ZA ZA00754754A patent/ZA754754B/en unknown
- 1975-07-23 CA CA232,062A patent/CA1055872A/en not_active Expired
- 1975-07-29 ES ES439793A patent/ES439793A1/en not_active Expired
- 1975-07-31 LU LU73126A patent/LU73126A1/xx unknown
- 1975-08-01 DE DE19752534383 patent/DE2534383A1/en not_active Withdrawn
- 1975-08-05 IT IT69033/75A patent/IT1041484B/en active
- 1975-08-06 BE BE158969A patent/BE832162A/en unknown
- 1975-08-07 AT AT0614275A patent/AT362744B/en not_active IP Right Cessation
- 1975-08-13 MX MX160142A patent/MX146349A/en unknown
- 1975-08-14 FR FR7525425A patent/FR2281971A1/en active Granted
- 1975-08-15 JP JP50099424A patent/JPS5146302A/ja active Pending
- 1975-08-15 GB GB3409575A patent/GB1467744A/en not_active Expired
- 1975-08-15 BR BR7505230*A patent/BR7505230A/en unknown
- 1975-08-15 PL PL1975182746A patent/PL97850B1/en unknown
-
1977
- 1977-08-26 TR TR18894A patent/TR18894A/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5146302A (en) | 1976-04-20 |
| FR2281971A1 (en) | 1976-03-12 |
| ZA754754B (en) | 1976-07-28 |
| ES439793A1 (en) | 1977-03-16 |
| AU8405175A (en) | 1977-02-24 |
| LU73126A1 (en) | 1976-11-11 |
| BE832162A (en) | 1975-12-01 |
| BR7505230A (en) | 1976-08-03 |
| ATA614275A (en) | 1980-11-15 |
| AT362744B (en) | 1981-06-10 |
| AR207472A1 (en) | 1976-10-08 |
| FR2281971B1 (en) | 1979-05-18 |
| MX146349A (en) | 1982-06-16 |
| GB1467744A (en) | 1977-03-23 |
| DE2534383A1 (en) | 1976-02-26 |
| TR18894A (en) | 1977-11-10 |
| NL7508618A (en) | 1976-02-18 |
| PL97850B1 (en) | 1978-03-30 |
| IT1041484B (en) | 1980-01-10 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4037330A (en) | Method and means for dry cooling bulk materials | |
| JPH0122538B2 (en) | ||
| GB1198603A (en) | Method and Apparatus for High Temperature Waste Disposal. | |
| CA1055872A (en) | Coal heater temperature control | |
| US4008042A (en) | Coal heating temperature control | |
| CN103925607A (en) | Positive-pressure direct-firing pulverizing system based on segmented temperature control and control method thereof | |
| US4193554A (en) | Method and apparatus for the drying and fine-grinding of coal | |
| US4174947A (en) | Installation and process for regulating the preheating of coking coal | |
| US4530661A (en) | Apparatus for the calcination of fine grained material | |
| US5127772A (en) | Method and apparatus for the control of suspension density by use of a radiation source | |
| US3241505A (en) | System for regulating the supply of pulverized fuel slurry to a furnace | |
| GB981826A (en) | Fluidizable solid injection system for furnaces | |
| US4541572A (en) | Pulverizing, drying and transporting system for injecting a pulverized fuel into a blast furnace | |
| US2103453A (en) | Method of burning pulverized fuel | |
| US4270466A (en) | Method and apparatus for rendering an ignitable fuel-oxygen mixture inert | |
| US4356063A (en) | Pre-heated coal supply system for a coking oven battery | |
| US2292571A (en) | Method of burning dried sewage sludge and apparatus therefor | |
| CA1079065A (en) | Cement calcining apparatus | |
| US4750434A (en) | Mill/dryer gas temperature control | |
| US4321032A (en) | Process for the treatment of combustible granular and/or pulverulent material by drying and/or heating, and an installation for carrying out the process | |
| US2998200A (en) | System for producing pulverized coal | |
| US2484539A (en) | Means for rotary kiln temperature control | |
| US3121409A (en) | Method and apparatus for controlling the air supply to a pulverized coal firing system | |
| US3212879A (en) | Process and apparatus for controlling shaft furnaces | |
| US3306238A (en) | Fuel injection system for blast furnaces |