CA1201408A - Arrangement for heating cold wet coal with hot paticles - Google Patents
Arrangement for heating cold wet coal with hot paticlesInfo
- Publication number
- CA1201408A CA1201408A CA000409689A CA409689A CA1201408A CA 1201408 A CA1201408 A CA 1201408A CA 000409689 A CA000409689 A CA 000409689A CA 409689 A CA409689 A CA 409689A CA 1201408 A CA1201408 A CA 1201408A
- Authority
- CA
- Canada
- Prior art keywords
- coal
- solid particles
- arrangement
- heating
- hot
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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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
- 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
- C10B57/10—Drying
-
- 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
- F26B3/18—Drying solid materials or objects by processes involving the application of heat by conduction, i.e. the heat is conveyed from the heat source, e.g. gas flame, to the materials or objects to be dried by direct contact
- F26B3/20—Drying solid materials or objects by processes involving the application of heat by conduction, i.e. the heat is conveyed from the heat source, e.g. gas flame, to the materials or objects to be dried by direct contact the heat source being a heated surface, e.g. a moving belt or conveyor
- F26B3/205—Drying solid materials or objects by processes involving the application of heat by conduction, i.e. the heat is conveyed from the heat source, e.g. gas flame, to the materials or objects to be dried by direct contact the heat source being a heated surface, e.g. a moving belt or conveyor the materials to be dried covering or being mixed with heated inert particles which may be recycled
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Microbiology (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Organic Chemistry (AREA)
- Coke Industry (AREA)
- Solid Fuels And Fuel-Associated Substances (AREA)
- Drying Of Solid Materials (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
Cold wet coal is heated by admixing a plurality of hot solid bodies which have an initial temperature exceeding a desir-ed end temperature of the coal.
Cold wet coal is heated by admixing a plurality of hot solid bodies which have an initial temperature exceeding a desir-ed end temperature of the coal.
Description
l The present invention relates to a method of heating cold, wet coal, particularly coal for subsequent coking, as well as to an arrangement for heating coke. In addition to the above mentioned utility of the invention for heating coking coal, it is also applicable to the heating of coal for other purposes, for example for heating coal to be briquetted. 11ereinbelow the in-vention will be illustrated as an example for a coking coal.
Coal for coking is generally available with surrounding temperature 0-20C with a water content of up to 15~ and a grain size distribution of l-lO mm, wherein approxirnately 85~ of the grain size is less than 3 mm. For using it in coking ovens, cok-ing properties of coal are very important, such as dilatation, swelling degree, fluidity, etc. It is known that, by heating the coal to 200-250C, the coking time of the coking oven can be con-siderably reduced, for example from 20 hours to l~ hours, and by heating the water is removed to an insignificant residual content It is important that during heating the coking properties of the coal not be affected. In contrast, it has been found that by proper heating the coking of the coal in a coking oven can be im-proved so that coals which are difficult to coke without treat-ment can be used in coking ovens with success.
During heating particularly impact-type heating of in-dividual coal particles, comminution of coal can take place, which is undesirable, inasmuch as this increases the fine-grain fraction in an unacceptable manner. The coal heating must there-fore be performed very carefully. To prevent oxidation, the coal heating 1~USt be continuously performed without access of oxygen.
Various process principles are known for implementation of coal heating, some of which have been extensively used, such as for example heating by hot gas flying stream, or by indirect ~' L4~3 heating via heat exchange surfaces installed in the driers, or by direct heating by hot gas in moYable shakers, for example in a rotary drum. A11 these methods are characterized by high investment costs, considerable machine expenses, and great energy consumption. Moreover, displacement of the grain distribution to-wards finer grain takes place during these processes. Also, other coking properties, such as for example dilation and fluidity, are undesirably affected. A device for heating coal which is particularly advantageous in respect to energy consumption of the coking oven is described in the Canadian patent application 402,417, in which the energy recovered during cooling of the generated coke can be used for heating the coal. This device, however, also possesses some disadvantages.
Accordingly, it is an object of the present invention to provide a method of heating coal at low cost and which is ~nargy-economical, and with which coking properties of the coal are guaranteed, and comminution of coal particles is avoided.
Another object of the present invention is to provide an arrangement which attains the above mentioned advantageous re-sults.
In keeping with these objects, and with others which will become apparent hereinafter, one feature of the present in~
vention resides in a method of heating coal, in which hot solid particles with an initial temperature exceeding a desired end temperature of the coal are admixed with cold wet coal to heat the latter.
In accordance with another feature of the present in-vention, the solid particles have a continuously uniform shape without edges, sharp corners, projections, and grooves. Par-ticularly suitable are solid particles having a spherical shape.
~,",~, ¢~
1 Moreover, it is advan~tageous for good mixing of the coal with the heat-conductive solid particles when the solid particles are pro-vided in a narrow size range, for example formed as spheres with a diameter smaller than 40 mm.
In accordance with other features of the present inven-tion, the solid particles can be composed of metal materials, for example steel or cast iron, or of non-metallic materials, for ex ample ceramics or porcelain. The solid particles can also be com-posed of mechanically strong and temperature-resistant synthetic plastic materials.
The solid particles can be of natural origin, for ex-ample pebblestone, which can be found advantageously in a prede-termined shape and size. It is important for the selection of the material of the solid particles that they be wear-resistant.
Thus, in the event of non-metallic materials, mechanical wear re-sistance in accordance with DIN 52108 is advantageously smaller then 0.45 cm3/cm2.
Heat properties of the solid partieles are of particular importanee. It is reeommended to use solid particles with a heat permeability (J/m2KsO 5) whieh is smaller than 16,000, preferably smaller than 5,000. The thermal eonduetivity (m2/h) must be smaller than 700 10 4, advantageously smaller than 150 10 4.
The speeifie heat of the solid particles (J/kgK) must be greater than 400, advantageously greater than 800. In connection with this it is expeeted, as desired, that the quantity of the heat-transmitting solid partieles can be retained as small as possible rela-tive to the coal quantity to be heated. It is thereby ad-vantageous to select a material having maximum heat-accumulating properties.
To prevent the situation wherein the cold wet coal is ~ ?~
1 subjected to heat impacts, the temperature of the heat-trans-mitting solid particles is kept within certain limits. It has been recognized that the temperature of the solid particles must be selected so as to not exceed 500C, and the solid particles must be composed of a material whose heat permeability and thermal conductivity provide for fine transmission of the heat energy accumulated in the solid particles to the coal.
Steam produced during evaporation of the coil moisture shields the coal particles as protective gas against the undesir-able influence of the air oxygen upon the coke-favorable proper-ties of the coal.
~ eating of the solid particles can be performed in any manner. When a coke dry cooling device is available in a coking plant, it is advantageous to use heated cooling gas produced thereErom. This cooling gas can be supplied in a container accommodating the solid particles and gives out a part of its heat to the latter, prior to flowing back to the coke dry cooliny device.
Another possibility for heating the solid particles is to provide a separate combustion chamber and to use exhaust gas generated from a solid, liquid or gaseous fuel to heat the solid particles in heat exchange therewith. The installation of such a combustion chamber is advantageous when a coke dry cooling de-vice is not recommended. This combustion chamber guarantees heating of the coal in desirable quantities in the event of failure or operational disruptions of the coke dry cooling de-vice. Since the exhaust gases produced by combustion have an excessively high temperature for heating the coal of approximately 1,400C their temperature can be lowered, for example by admixing a water vapor in a required quantity.
1 - The novel features which are considered characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construc-tion and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawing.
FIG. 1 is a view showing a principal sketch of a method of heating coal in accordanee with the present invention;
FIG. 2 is a view schematically showing an arrangement for heating coal in accordance with the present invention, in-cluding a travelling layer drier formed as a vertically stand~ng container;
FIG. 3 is a view sukstantially corresponding to the view of FIG. 2, but showing the travelling layer drier with a different discharging and separating deviee;
FIG. 4 is a view substantially corre~ponding to the view of FIG. 2, but showing the travelling layer drier with a built-in shaking screen;
FIG. 5 is a view showing an arrangement in accordance with the present invention, formed as a multi-stage drier;
FIG. 6 is a view showing an arrange~ent in accordance with the present invention, which includes a travelling layer drier formed as a rotatable drum;
FIG. 7 is a view showing the inventive arrangement with a travelling layer drier formed as an inclined container;
and FIG. 8 is a view showing the inventive arrangement in-cluding a travelling layer drier formed as an evaporating chute.
In accordance with FIG. 1, wet coal is supplied from ~.?~
1 a coal bi.n via a feeding device B and heated solid particles are supplied from a solid particle heater C via a dosing device D, with the aid of a suitable distributing device E together to a device for heating the coal F. The coal and the solid particles travel together in a direct stream through the device F. The solid particles give out a part of the energy accumulated there-in to the coal. The removed coal moisture is withdrawn via a suitable steam space.
The thus heated coal is separated from the solid par-ticles in a suitable separating device G, for example a shaking sc:reen t and supplied in a suitable manner to a coke oven. The solid particles are returned back, for example by a bucket con-veyor H, to the solid particle heater C. The solid particle heater C can operate with smoke or exhaust gases produced by com-bustion. It is especially advantageous in the sense of energy consumption of the coking oven when hot gas of a coke dry cooling is utilized. The hot gas supply is identified by reference le-tter I, and -the hot gas withdrawal is identified by reference letter K.
In the embodiments shown hereinbelow for heating coal, gases from a coke dry cooling are utilized for this purpose.
In the arrangement shown in FIG~ 2, the wet coal is supplied from a supply bin 1 via a cellular wheel sluice 2 into a travelling layer drier 3 which is formed here as a vertically extending cylindrical contain~r. Sol~id particles, for example having the shape of steel balls, are continuously supplied from a heater 4 via the cellular wheel sluice 5 into the same travelling layer drier. The coal and the admixed balls flow continuously through the travelling layer drier from above downwardly, and the coal and balls are maintained in constant movement by a stirring ~L~2Q~
1 m~echanism 6 with stirring arms 7. The drive of the stirring mechanism is identified by reference numeral 8. The stirring mechanism guarantees that new coal grains always come in contact with the hot balls, so that the coal is subjected generally to a substantially uniform thermal treatment. The resistance dur-ing downward flow of the coal is overcome by its own weight and the weight of the balls, and the variable dwell time of the coal in the travelling layer drier is determined by withdrawal of the coal and the balls in the lower region.
The discharge of the coal and balls from the travel.ling layer drier 3 is carried out by a transporting screw 9 which leads to a pneurnatic separating device 10. The coal, heated to approximately 200C, is separated from the balls in the separat-ing device 10 with the aid of a carrier gas supplied via a con-duit 11, and is transported via a conduit 12 to a not shown coal tower with a preceding separator. The speciically heavier balls fall in an intercepting container 13 and are supplied with the aid of a transporting device 14 (a chain conveyor, a bucket con-veyor, etc.) to the heater 4. The discharge of the coal and balls from the travelling layer drier can be facilitated by a bin-emptying device 15 of suitable construction arranged in the lower region of the travelling layer drier.
The waste-gas-containing steam separated in the travelling layer drier 3 from the wet coal is withdrawn in dif-ferent planes via conduits 16 and supplied via a cyclone lB, a conduit 19 and a blower 20 into a circulating washer 21 in which washing of impurities takes place in addition to condensation.
Instead of the above shown washer construction, other construc-tions can also be utilized, such as for example a venturi washer.
The coal grains separated in the cyclone 18 travel via ~?~Q~8 1 a cellular wheel sluice 22 and a conduit 23 to the separating de-vice 10, from which they are supplied together with the heated coal to the above mentioned coal tower~
The liquid flowing from the circulating washer 21 is supplied via a conduit 24 and a pump 25 to a cooling tower 26 in which further cooling to approximately 20C takes place. The cooled liquid is supplied after this via conduit 27 into a cool-ing water distributor 28. From here the required cooling water is further supplied via conduits 29, 30 and 31 in different planes to the circulating washer 21. The gas escaping from the circulating washer is drawn via a conduit 32 and supplied to a not shown fireplace.
The hot stream of the cooling gas exiting from the upper part of a coke dry cooler 33 with a temperature of approximately 800C is withdrawn via a conduit 34. A conduit 35 branches from the latter and is arranged so that a partial stream of the gas is supplied via a heat exchanger 36 and then to the coke dry cooler again. The remaining hot cooling gas travels via conduit 37 to the heater 4 in which it is used for heat transmission to the balls accommodated in the latter. This gas leaves the heater via a conduit 38 and after passing a blower 39 with a tempera-ture of approximately 220C is supplied in the conduit 35. From this conduit one part of the gas is supplied via conduit 61 into a central region, and another part is supplied via a conduit 32 in a lower region of the coke dry cooler. From a conduit 38 branches a conduit 40 through which a partial stream of the gas can be blown via a fireplace 41 to the atmosphere. Moreover~ a bypass conduit 42 is provided behind the blower 39 and communi-cates with the conduit 37 to the heater 4. The hot gas flowing from the coke dry cooler via the conduit 34 can be admixed via 1 *he kypass conduit for temperature regulation with cold gas from the conduit 38.
In order to guarantee that, in the event of failure or operational distortions of the coke dry cooler 33, the heating of the balls in the heater 4 is not undesirably affected, a com-bustion chamber 43 is additionally provided. The combustion chamber 43 is supplied via conduit 44 with a gaseous, liquid or solid fuel, and via a conduit 45 with a required combustion air.
Since hot gas generated during combustion has an excessively high temperature of approximately 1 400C, water vapor is supplied via a conduit 46 which branches from the conduit 19. By addition of the water vapor, the combustion gas temperature is reduced to the desired value of for example 800-900C. With this tempera-ture, the combustion gas is supplied via a conduit 47 in the conduit 37 which leads to the heater 4. A not shown regulating valve is provided in the conduit 47, so that the withdrawn gas quantity is throttled in some cases and the combustion chamber 43 can be used if necessary as an additional heating source.
The arrangement shown in FIG. 3 differs Erom the arrangement shown in FIG. 2, in that the Separ~Rting device is formed here as a shaking screen 48 located under the travelling layer drier. The balls fall from it into the intercepting con-tainer 13, whereas the coal travels via a conduit 49 to a bucket conveyor 50 which transports the coal to a not shown coal tower.
The arrangement shown in FIG. 4 shows the vertically standing travelling layer drier 3, in which, however, the sepa-rating device is Eormed as a shaking screen 51 which is built in the lower region of the travelling layer drier. The separated balls are supplied into the intercepting container 13. The coal is transported with the aid of a transporting screw 52 and the conduit 49 to the bucket conveyor 50. For providing disaggrega-tion of the coal and avoiding nesting of balls in the center of the travelling layer drier, the heat transmitting solid particles are formed as steel balls, and additional electromagnets 53 are provided outside of the travelling layer drier in offset relation-ship relative to one another. The electromagnets 53 are period-ically activated so that the steel balls are maintained in dis-bributed condition in the drier. The dwell time of the coal in the travelling layer drier is determined in this embodiment by the transporting screw 52, on the one hand, and by the position of throttliny flaps 54 in the interior of the travelling bed drier.
The arrangement shown in FIG. 5 has the travelling lay-er drier 3 which is formed as a multi-stage or multi-storv drier.
The supplied coal and the balls are mixed by the stirring mecha-nism 6 with the stirring arms 7 and travel via openings in story bottoms 55 from one story to the other.
The arrangement shown in FIG. 6 has the travelling layer drier 3 which is formed as an inclined rotary drum. The coal and balls are supplied to the drum via a transporting screw 56 and mixed in the former. The discharge is also performed via a transporting screw 57 which supplies the material to the pneumat-ic separating device 10. The withdrawal of the steam from the drum is performed via a conduit 58 which, as can be seen from the drawings, extends into t~a interior of the drum. A plurality of driving elements to act on solid particles can be arranged within the rotary drum 3.
The arrangement shown in FIG. 7 has the travelling layer drier which is formed as an inclined container. The supply and discharge of the material is carried out here similarly to the arrangement of FIG. 6 by the transporting screw 56 and 57.
The steel balls are alternately displaced by electromagnets 60 which are provided at the upper and lower sides of the container and offset relative to one another. Thereby the steel balls move , . 11 1 along a sinusoidal path from the inlet to the outlet of the con-tainer. This prevents segregation of the material and provides for disaggregation of coal.
FIG. 8, finally, shows the arrangement in which the travelling layer drier 3 is formed as an inclined vibrating chute.
For preventing settling of the steel balls because of their great-er specific weight on the bottom of the chute, the electromagnets 60 provided at the upper side of the vibration chute are periodi-cally actuated and thereby provide for a continuous sinusoidal path of the steel balls.
When the method is performed and the arrangement is de-signed in accordance with the present invention, -the following, highly advantageous results are obtained. The invention provides for a great speciic heat exchange surface, which depending upon the radius of balls is equal to 200-600 m2/m3. There is a high heat exchange coefficient which amounts to 80-400 W/m2K. There are relatively small drying volumes, such as 4-16 m3 relative to 100 t/h o the dry coal. A great power density is obtained, equal to 1,050-3,200 3 . A low consumption of electrical energy is required, namely 20-60 kW for the transportation of the solid particles with a total consumption of approximately 600 kW, re-lative to 100 t/h of coal. It requires a little staff for opera-tion and maintenance of the device, and low maintenance costs.
It c~uses insignificant environmental problems. There is no danger of undesirably affecting the coking properties of the coal, since the input temperature of the solid particles is equal at maximum to approximately ~00C.
Two examples are presented hereinbelow in a table, wherein they are based on a coal quantity to be heated of 100 t/h and steel balls of steel 35.8 in one example, and silica brick balls, in the other example.
1 Solid Particles steel silica Material coal balls brick dosing quantity (t/h) 100 320 247 input temperature (C) 20 400 400 output temperature (C) 200 220 238 moisture of entering coal (%) 9 - -moisture of exiting coal (%) 0 diameter of apparatus ~m) - 1.5 1.5 10 length of apparatus (m) - 2.1 6.5 length of entire moisture separation (m) - 1.4 4.3 diameter of balls (mm) - 15 15 dwell ti.me of coal (S) - 100 139 travelling speed of coal (m/min) - 1.9 3 volume ratio (m3 coal/m3balls) - 2.8 1.2 mass ratio (t eoal/t balls) - 0.28 0.42 theoretieally required eireu-lating conductivity of balls (kW) - 15 10 speeiic surEaee of balls (m2/m3) - 300 300 20thermal eonduetivity (W/mK) 0.27 45 0.37 speeifie thermal capaeity (J/kg K) 1423 683 1013 1 It will be understood that each of the elements describ-ed above, or two or more together, may also find a useful applica-tion in other types of constructions dif~ering from the types described above.
While the invention has been illustrated and described as embodied in a method of and an arrangement for heating cold, wet coal, it is notintended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present inven-].0 tion.
Coal for coking is generally available with surrounding temperature 0-20C with a water content of up to 15~ and a grain size distribution of l-lO mm, wherein approxirnately 85~ of the grain size is less than 3 mm. For using it in coking ovens, cok-ing properties of coal are very important, such as dilatation, swelling degree, fluidity, etc. It is known that, by heating the coal to 200-250C, the coking time of the coking oven can be con-siderably reduced, for example from 20 hours to l~ hours, and by heating the water is removed to an insignificant residual content It is important that during heating the coking properties of the coal not be affected. In contrast, it has been found that by proper heating the coking of the coal in a coking oven can be im-proved so that coals which are difficult to coke without treat-ment can be used in coking ovens with success.
During heating particularly impact-type heating of in-dividual coal particles, comminution of coal can take place, which is undesirable, inasmuch as this increases the fine-grain fraction in an unacceptable manner. The coal heating must there-fore be performed very carefully. To prevent oxidation, the coal heating 1~USt be continuously performed without access of oxygen.
Various process principles are known for implementation of coal heating, some of which have been extensively used, such as for example heating by hot gas flying stream, or by indirect ~' L4~3 heating via heat exchange surfaces installed in the driers, or by direct heating by hot gas in moYable shakers, for example in a rotary drum. A11 these methods are characterized by high investment costs, considerable machine expenses, and great energy consumption. Moreover, displacement of the grain distribution to-wards finer grain takes place during these processes. Also, other coking properties, such as for example dilation and fluidity, are undesirably affected. A device for heating coal which is particularly advantageous in respect to energy consumption of the coking oven is described in the Canadian patent application 402,417, in which the energy recovered during cooling of the generated coke can be used for heating the coal. This device, however, also possesses some disadvantages.
Accordingly, it is an object of the present invention to provide a method of heating coal at low cost and which is ~nargy-economical, and with which coking properties of the coal are guaranteed, and comminution of coal particles is avoided.
Another object of the present invention is to provide an arrangement which attains the above mentioned advantageous re-sults.
In keeping with these objects, and with others which will become apparent hereinafter, one feature of the present in~
vention resides in a method of heating coal, in which hot solid particles with an initial temperature exceeding a desired end temperature of the coal are admixed with cold wet coal to heat the latter.
In accordance with another feature of the present in-vention, the solid particles have a continuously uniform shape without edges, sharp corners, projections, and grooves. Par-ticularly suitable are solid particles having a spherical shape.
~,",~, ¢~
1 Moreover, it is advan~tageous for good mixing of the coal with the heat-conductive solid particles when the solid particles are pro-vided in a narrow size range, for example formed as spheres with a diameter smaller than 40 mm.
In accordance with other features of the present inven-tion, the solid particles can be composed of metal materials, for example steel or cast iron, or of non-metallic materials, for ex ample ceramics or porcelain. The solid particles can also be com-posed of mechanically strong and temperature-resistant synthetic plastic materials.
The solid particles can be of natural origin, for ex-ample pebblestone, which can be found advantageously in a prede-termined shape and size. It is important for the selection of the material of the solid particles that they be wear-resistant.
Thus, in the event of non-metallic materials, mechanical wear re-sistance in accordance with DIN 52108 is advantageously smaller then 0.45 cm3/cm2.
Heat properties of the solid partieles are of particular importanee. It is reeommended to use solid particles with a heat permeability (J/m2KsO 5) whieh is smaller than 16,000, preferably smaller than 5,000. The thermal eonduetivity (m2/h) must be smaller than 700 10 4, advantageously smaller than 150 10 4.
The speeifie heat of the solid particles (J/kgK) must be greater than 400, advantageously greater than 800. In connection with this it is expeeted, as desired, that the quantity of the heat-transmitting solid partieles can be retained as small as possible rela-tive to the coal quantity to be heated. It is thereby ad-vantageous to select a material having maximum heat-accumulating properties.
To prevent the situation wherein the cold wet coal is ~ ?~
1 subjected to heat impacts, the temperature of the heat-trans-mitting solid particles is kept within certain limits. It has been recognized that the temperature of the solid particles must be selected so as to not exceed 500C, and the solid particles must be composed of a material whose heat permeability and thermal conductivity provide for fine transmission of the heat energy accumulated in the solid particles to the coal.
Steam produced during evaporation of the coil moisture shields the coal particles as protective gas against the undesir-able influence of the air oxygen upon the coke-favorable proper-ties of the coal.
~ eating of the solid particles can be performed in any manner. When a coke dry cooling device is available in a coking plant, it is advantageous to use heated cooling gas produced thereErom. This cooling gas can be supplied in a container accommodating the solid particles and gives out a part of its heat to the latter, prior to flowing back to the coke dry cooliny device.
Another possibility for heating the solid particles is to provide a separate combustion chamber and to use exhaust gas generated from a solid, liquid or gaseous fuel to heat the solid particles in heat exchange therewith. The installation of such a combustion chamber is advantageous when a coke dry cooling de-vice is not recommended. This combustion chamber guarantees heating of the coal in desirable quantities in the event of failure or operational disruptions of the coke dry cooling de-vice. Since the exhaust gases produced by combustion have an excessively high temperature for heating the coal of approximately 1,400C their temperature can be lowered, for example by admixing a water vapor in a required quantity.
1 - The novel features which are considered characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construc-tion and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawing.
FIG. 1 is a view showing a principal sketch of a method of heating coal in accordanee with the present invention;
FIG. 2 is a view schematically showing an arrangement for heating coal in accordance with the present invention, in-cluding a travelling layer drier formed as a vertically stand~ng container;
FIG. 3 is a view sukstantially corresponding to the view of FIG. 2, but showing the travelling layer drier with a different discharging and separating deviee;
FIG. 4 is a view substantially corre~ponding to the view of FIG. 2, but showing the travelling layer drier with a built-in shaking screen;
FIG. 5 is a view showing an arrangement in accordance with the present invention, formed as a multi-stage drier;
FIG. 6 is a view showing an arrange~ent in accordance with the present invention, which includes a travelling layer drier formed as a rotatable drum;
FIG. 7 is a view showing the inventive arrangement with a travelling layer drier formed as an inclined container;
and FIG. 8 is a view showing the inventive arrangement in-cluding a travelling layer drier formed as an evaporating chute.
In accordance with FIG. 1, wet coal is supplied from ~.?~
1 a coal bi.n via a feeding device B and heated solid particles are supplied from a solid particle heater C via a dosing device D, with the aid of a suitable distributing device E together to a device for heating the coal F. The coal and the solid particles travel together in a direct stream through the device F. The solid particles give out a part of the energy accumulated there-in to the coal. The removed coal moisture is withdrawn via a suitable steam space.
The thus heated coal is separated from the solid par-ticles in a suitable separating device G, for example a shaking sc:reen t and supplied in a suitable manner to a coke oven. The solid particles are returned back, for example by a bucket con-veyor H, to the solid particle heater C. The solid particle heater C can operate with smoke or exhaust gases produced by com-bustion. It is especially advantageous in the sense of energy consumption of the coking oven when hot gas of a coke dry cooling is utilized. The hot gas supply is identified by reference le-tter I, and -the hot gas withdrawal is identified by reference letter K.
In the embodiments shown hereinbelow for heating coal, gases from a coke dry cooling are utilized for this purpose.
In the arrangement shown in FIG~ 2, the wet coal is supplied from a supply bin 1 via a cellular wheel sluice 2 into a travelling layer drier 3 which is formed here as a vertically extending cylindrical contain~r. Sol~id particles, for example having the shape of steel balls, are continuously supplied from a heater 4 via the cellular wheel sluice 5 into the same travelling layer drier. The coal and the admixed balls flow continuously through the travelling layer drier from above downwardly, and the coal and balls are maintained in constant movement by a stirring ~L~2Q~
1 m~echanism 6 with stirring arms 7. The drive of the stirring mechanism is identified by reference numeral 8. The stirring mechanism guarantees that new coal grains always come in contact with the hot balls, so that the coal is subjected generally to a substantially uniform thermal treatment. The resistance dur-ing downward flow of the coal is overcome by its own weight and the weight of the balls, and the variable dwell time of the coal in the travelling layer drier is determined by withdrawal of the coal and the balls in the lower region.
The discharge of the coal and balls from the travel.ling layer drier 3 is carried out by a transporting screw 9 which leads to a pneurnatic separating device 10. The coal, heated to approximately 200C, is separated from the balls in the separat-ing device 10 with the aid of a carrier gas supplied via a con-duit 11, and is transported via a conduit 12 to a not shown coal tower with a preceding separator. The speciically heavier balls fall in an intercepting container 13 and are supplied with the aid of a transporting device 14 (a chain conveyor, a bucket con-veyor, etc.) to the heater 4. The discharge of the coal and balls from the travelling layer drier can be facilitated by a bin-emptying device 15 of suitable construction arranged in the lower region of the travelling layer drier.
The waste-gas-containing steam separated in the travelling layer drier 3 from the wet coal is withdrawn in dif-ferent planes via conduits 16 and supplied via a cyclone lB, a conduit 19 and a blower 20 into a circulating washer 21 in which washing of impurities takes place in addition to condensation.
Instead of the above shown washer construction, other construc-tions can also be utilized, such as for example a venturi washer.
The coal grains separated in the cyclone 18 travel via ~?~Q~8 1 a cellular wheel sluice 22 and a conduit 23 to the separating de-vice 10, from which they are supplied together with the heated coal to the above mentioned coal tower~
The liquid flowing from the circulating washer 21 is supplied via a conduit 24 and a pump 25 to a cooling tower 26 in which further cooling to approximately 20C takes place. The cooled liquid is supplied after this via conduit 27 into a cool-ing water distributor 28. From here the required cooling water is further supplied via conduits 29, 30 and 31 in different planes to the circulating washer 21. The gas escaping from the circulating washer is drawn via a conduit 32 and supplied to a not shown fireplace.
The hot stream of the cooling gas exiting from the upper part of a coke dry cooler 33 with a temperature of approximately 800C is withdrawn via a conduit 34. A conduit 35 branches from the latter and is arranged so that a partial stream of the gas is supplied via a heat exchanger 36 and then to the coke dry cooler again. The remaining hot cooling gas travels via conduit 37 to the heater 4 in which it is used for heat transmission to the balls accommodated in the latter. This gas leaves the heater via a conduit 38 and after passing a blower 39 with a tempera-ture of approximately 220C is supplied in the conduit 35. From this conduit one part of the gas is supplied via conduit 61 into a central region, and another part is supplied via a conduit 32 in a lower region of the coke dry cooler. From a conduit 38 branches a conduit 40 through which a partial stream of the gas can be blown via a fireplace 41 to the atmosphere. Moreover~ a bypass conduit 42 is provided behind the blower 39 and communi-cates with the conduit 37 to the heater 4. The hot gas flowing from the coke dry cooler via the conduit 34 can be admixed via 1 *he kypass conduit for temperature regulation with cold gas from the conduit 38.
In order to guarantee that, in the event of failure or operational distortions of the coke dry cooler 33, the heating of the balls in the heater 4 is not undesirably affected, a com-bustion chamber 43 is additionally provided. The combustion chamber 43 is supplied via conduit 44 with a gaseous, liquid or solid fuel, and via a conduit 45 with a required combustion air.
Since hot gas generated during combustion has an excessively high temperature of approximately 1 400C, water vapor is supplied via a conduit 46 which branches from the conduit 19. By addition of the water vapor, the combustion gas temperature is reduced to the desired value of for example 800-900C. With this tempera-ture, the combustion gas is supplied via a conduit 47 in the conduit 37 which leads to the heater 4. A not shown regulating valve is provided in the conduit 47, so that the withdrawn gas quantity is throttled in some cases and the combustion chamber 43 can be used if necessary as an additional heating source.
The arrangement shown in FIG. 3 differs Erom the arrangement shown in FIG. 2, in that the Separ~Rting device is formed here as a shaking screen 48 located under the travelling layer drier. The balls fall from it into the intercepting con-tainer 13, whereas the coal travels via a conduit 49 to a bucket conveyor 50 which transports the coal to a not shown coal tower.
The arrangement shown in FIG. 4 shows the vertically standing travelling layer drier 3, in which, however, the sepa-rating device is Eormed as a shaking screen 51 which is built in the lower region of the travelling layer drier. The separated balls are supplied into the intercepting container 13. The coal is transported with the aid of a transporting screw 52 and the conduit 49 to the bucket conveyor 50. For providing disaggrega-tion of the coal and avoiding nesting of balls in the center of the travelling layer drier, the heat transmitting solid particles are formed as steel balls, and additional electromagnets 53 are provided outside of the travelling layer drier in offset relation-ship relative to one another. The electromagnets 53 are period-ically activated so that the steel balls are maintained in dis-bributed condition in the drier. The dwell time of the coal in the travelling layer drier is determined in this embodiment by the transporting screw 52, on the one hand, and by the position of throttliny flaps 54 in the interior of the travelling bed drier.
The arrangement shown in FIG. 5 has the travelling lay-er drier 3 which is formed as a multi-stage or multi-storv drier.
The supplied coal and the balls are mixed by the stirring mecha-nism 6 with the stirring arms 7 and travel via openings in story bottoms 55 from one story to the other.
The arrangement shown in FIG. 6 has the travelling layer drier 3 which is formed as an inclined rotary drum. The coal and balls are supplied to the drum via a transporting screw 56 and mixed in the former. The discharge is also performed via a transporting screw 57 which supplies the material to the pneumat-ic separating device 10. The withdrawal of the steam from the drum is performed via a conduit 58 which, as can be seen from the drawings, extends into t~a interior of the drum. A plurality of driving elements to act on solid particles can be arranged within the rotary drum 3.
The arrangement shown in FIG. 7 has the travelling layer drier which is formed as an inclined container. The supply and discharge of the material is carried out here similarly to the arrangement of FIG. 6 by the transporting screw 56 and 57.
The steel balls are alternately displaced by electromagnets 60 which are provided at the upper and lower sides of the container and offset relative to one another. Thereby the steel balls move , . 11 1 along a sinusoidal path from the inlet to the outlet of the con-tainer. This prevents segregation of the material and provides for disaggregation of coal.
FIG. 8, finally, shows the arrangement in which the travelling layer drier 3 is formed as an inclined vibrating chute.
For preventing settling of the steel balls because of their great-er specific weight on the bottom of the chute, the electromagnets 60 provided at the upper side of the vibration chute are periodi-cally actuated and thereby provide for a continuous sinusoidal path of the steel balls.
When the method is performed and the arrangement is de-signed in accordance with the present invention, -the following, highly advantageous results are obtained. The invention provides for a great speciic heat exchange surface, which depending upon the radius of balls is equal to 200-600 m2/m3. There is a high heat exchange coefficient which amounts to 80-400 W/m2K. There are relatively small drying volumes, such as 4-16 m3 relative to 100 t/h o the dry coal. A great power density is obtained, equal to 1,050-3,200 3 . A low consumption of electrical energy is required, namely 20-60 kW for the transportation of the solid particles with a total consumption of approximately 600 kW, re-lative to 100 t/h of coal. It requires a little staff for opera-tion and maintenance of the device, and low maintenance costs.
It c~uses insignificant environmental problems. There is no danger of undesirably affecting the coking properties of the coal, since the input temperature of the solid particles is equal at maximum to approximately ~00C.
Two examples are presented hereinbelow in a table, wherein they are based on a coal quantity to be heated of 100 t/h and steel balls of steel 35.8 in one example, and silica brick balls, in the other example.
1 Solid Particles steel silica Material coal balls brick dosing quantity (t/h) 100 320 247 input temperature (C) 20 400 400 output temperature (C) 200 220 238 moisture of entering coal (%) 9 - -moisture of exiting coal (%) 0 diameter of apparatus ~m) - 1.5 1.5 10 length of apparatus (m) - 2.1 6.5 length of entire moisture separation (m) - 1.4 4.3 diameter of balls (mm) - 15 15 dwell ti.me of coal (S) - 100 139 travelling speed of coal (m/min) - 1.9 3 volume ratio (m3 coal/m3balls) - 2.8 1.2 mass ratio (t eoal/t balls) - 0.28 0.42 theoretieally required eireu-lating conductivity of balls (kW) - 15 10 speeiic surEaee of balls (m2/m3) - 300 300 20thermal eonduetivity (W/mK) 0.27 45 0.37 speeifie thermal capaeity (J/kg K) 1423 683 1013 1 It will be understood that each of the elements describ-ed above, or two or more together, may also find a useful applica-tion in other types of constructions dif~ering from the types described above.
While the invention has been illustrated and described as embodied in a method of and an arrangement for heating cold, wet coal, it is notintended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present inven-].0 tion.
Claims (8)
1. An arrangement for heating cold wet coal for a subsequent coking by hot solid particles, comprising means for sypplying cold wet coal means for supplying hot solid particles with an initial temperature exceeding a desired end temperature of coal; means for admixing the hot solid particles, supplied from said solid particles supplying means, with the coal supplied from said coal supplying means, so as to thereby heat the coal, said admixing means including at least one travelling layer drier positioned below said solid particle supplying means and said coal supplying means and connected thereto for receiving the wet coal and hot solid particles, said travelling layer drier including a vertically standing substantially cylindrical container, and a stirring mechanism for continually stirring said hot solid particles with the coal to ensure constant contact therebetween within said container; and means for separating the coal from the solid particles after heating of the coal, said separating means being arranged downstream of said container.
2. An arrangement as defined in claim 1, wherein said travelling layer drier of said admixing means is formed as a multiple-stage drier.
3. An arrangement as defined in claim 1, wherein said travelling layer drier of said admixing means is formed as a vibrating chute.
4. An arrangement as defined in claim 3, wherein the solid particles have magnetic properties, said vibrating chute having an outer side and being provided at said outer side with an electromagnet periodically actuated and acting upon the solid particles.
5. An arrangement as defined in claim 1, wherein said stirring mechanism is positioned within said container.
6. An arrangement as defined in claim 5, wherein said separating means includes a shaking screen arranged to separate the coal from the solid particles after heating the former.
7. An arrangement as defined in claim 5, wherein said separating means includes a pneumatic separating device arranged to separate the coal from the solid particles after heating the former.
8. An arrangement as defined in claim 5, wherein the solid particles have magnetic properties, said container having a wall and being provided on said wall with an electromagnet arranged outside of said wall and operative for acting upon the solid particles.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19813133491 DE3133491A1 (en) | 1981-08-25 | 1981-08-25 | METHOD AND DEVICE FOR HEATING COAL |
| DEP3133491.1 | 1981-08-25 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1201408A true CA1201408A (en) | 1986-03-04 |
Family
ID=6140020
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000409689A Expired CA1201408A (en) | 1981-08-25 | 1982-08-18 | Arrangement for heating cold wet coal with hot paticles |
Country Status (11)
| Country | Link |
|---|---|
| EP (1) | EP0073368B1 (en) |
| JP (1) | JPS5847093A (en) |
| AR (1) | AR228907A1 (en) |
| AT (1) | ATE24331T1 (en) |
| AU (1) | AU551656B2 (en) |
| BR (1) | BR8204941A (en) |
| CA (1) | CA1201408A (en) |
| DE (2) | DE3133491A1 (en) |
| ES (1) | ES8305404A1 (en) |
| IN (1) | IN158088B (en) |
| ZA (1) | ZA825368B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102012012417B4 (en) | 2012-06-25 | 2019-06-13 | Thyssenkrupp Industrial Solutions Ag | Method and apparatus for improved preheating of coal by heat exchange with the cooling gas of a Kokstrockenkühlanlage |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB407665A (en) * | 1932-06-17 | 1934-03-22 | Pierre Eugene Henri Forsans | Improvements in or relating to the treatment of coal and like materials |
| GB744742A (en) * | 1950-05-11 | 1956-02-15 | Weber Ludwig | A process for the gasification of fine-grained and like fuels |
| US3265608A (en) * | 1962-02-02 | 1966-08-09 | Technikoil Inc | Method for pyrolyzing solid carbonaceous materials |
| JPS4894050A (en) * | 1972-03-14 | 1973-12-04 | ||
| JPS5084959A (en) * | 1973-11-29 | 1975-07-09 | ||
| JPS5327162A (en) * | 1976-08-25 | 1978-03-14 | Yamato Sanko Seisakushiyo Kk | Drying apparatus utilizing heated ball medium |
| US4247987A (en) * | 1979-09-26 | 1981-02-03 | Exxon Research & Engineering Co. | Continuous countercurrent fluid-solids contacting process stabilized by a magnetic field |
-
1981
- 1981-08-25 DE DE19813133491 patent/DE3133491A1/en not_active Withdrawn
-
1982
- 1982-07-07 IN IN515/DEL/82A patent/IN158088B/en unknown
- 1982-07-27 ZA ZA825368A patent/ZA825368B/en unknown
- 1982-08-03 AR AR290208A patent/AR228907A1/en active
- 1982-08-10 EP EP82107206A patent/EP0073368B1/en not_active Expired
- 1982-08-10 DE DE8282107206T patent/DE3274746D1/en not_active Expired
- 1982-08-10 AT AT82107206T patent/ATE24331T1/en not_active IP Right Cessation
- 1982-08-13 ES ES514984A patent/ES8305404A1/en not_active Expired
- 1982-08-18 CA CA000409689A patent/CA1201408A/en not_active Expired
- 1982-08-24 BR BR8204941A patent/BR8204941A/en unknown
- 1982-08-24 AU AU87555/82A patent/AU551656B2/en not_active Ceased
- 1982-08-25 JP JP57147515A patent/JPS5847093A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| ZA825368B (en) | 1983-05-25 |
| JPS5847093A (en) | 1983-03-18 |
| IN158088B (en) | 1986-08-30 |
| EP0073368B1 (en) | 1986-12-17 |
| EP0073368A3 (en) | 1984-04-11 |
| ES514984A0 (en) | 1983-05-01 |
| EP0073368A2 (en) | 1983-03-09 |
| DE3274746D1 (en) | 1987-01-29 |
| BR8204941A (en) | 1983-08-02 |
| ES8305404A1 (en) | 1983-05-01 |
| AU551656B2 (en) | 1986-05-08 |
| ATE24331T1 (en) | 1987-01-15 |
| DE3133491A1 (en) | 1983-03-17 |
| AU8755582A (en) | 1983-03-03 |
| AR228907A1 (en) | 1983-04-29 |
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| MKEX | Expiry |