CN217556219U - Online cooling device of rotary hearth furnace - Google Patents
Online cooling device of rotary hearth furnace Download PDFInfo
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- CN217556219U CN217556219U CN202221024639.XU CN202221024639U CN217556219U CN 217556219 U CN217556219 U CN 217556219U CN 202221024639 U CN202221024639 U CN 202221024639U CN 217556219 U CN217556219 U CN 217556219U
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Abstract
The invention discloses an online cooling device of a rotary hearth furnace, belongs to the technical field of direct reduction of the rotary hearth furnace, and solves the problems of high carbon emission amount, low product metallization rate and no recovery of high-temperature sensible heat of metallized pellets in direct reduction of the rotary hearth furnace. The device is arranged on a rotary hearth furnace; the rotary hearth furnace comprises a reduction section, a first cooling section and a discharge end which are sequentially communicated; the online cooling device comprises a hydrogen-rich gas generation unit and a hydrogen-rich gas conveying unit which are connected, wherein the hydrogen-rich gas conveying unit comprises a conveying pipeline which is arranged at the top of the rotary hearth furnace and is communicated with the first cooling section of the rotary hearth furnace; a second cooling section is arranged between the reduction section and the first cooling section; a plurality of vertical flue gas baffles which are parallel to each other and have the same structure are arranged below the furnace top wall of the second cooling section. The invention can reduce the reduction energy consumption of the rotary hearth furnace.
Description
Technical Field
The invention relates to a direct reduction iron-making device of a rotary hearth furnace, in particular to an online cooling device of the rotary hearth furnace.
Background
The direct reduction process of rotary hearth furnace is one new non-coking coal ironmaking technology, and is used mainly in treating zinc containing dust and special iron ore resource.
The direct reduction process of rotary hearth furnace is one new non-coking coal ironmaking technology, and is used mainly in treating zinc containing dust and special iron ore resource. In the last 50 th century, the Ross corporation, midrex, USA, invented a rotary hearth furnace direct reduction method for carbon-containing pellets, named Fastmet technology, and performed 2t/h small-scale thermal consolidation experiments. In 1974, international nickel group (Inmetco) of canada started to study the process of treating stainless steel oxide dust waste by a rotary hearth furnace, and directly charging the metallized pellets pre-reduced by the rotary hearth furnace into an electric furnace for smelting, which is named as the Inmetco process. At the end of the last century, japan Kobe Steel works and Midrex corporation of America developed a new process for directly reducing iron in a rotary hearth furnace, so that metallized pellets are reduced and melted in the rotary hearth furnace to generate iron blocks, and simultaneously slag and iron are separated, so that the process is named as a third-generation iron making method (Itmk 3). The Itmk3 process has been tested industrially and has commercial production capacity. The rotary hearth furnace process has succeeded in treating zinc-containing dust of iron and steel enterprises, and is gradually popularized and applied to extraction of special iron ore resources.
In recent years, the rotary hearth furnace technology is rapidly developed in China, and a plurality of direct reduction production lines of the rotary hearth furnace are built in sequence in China. From the practical operation of the domestic rotary hearth furnace, the rotary hearth furnace has the characteristics of high resource utilization efficiency and high lead and zinc removal rate. Although the rotary hearth furnace technology has achieved great success in China and is gradually popularized and used for smelting some special iron ore resources, the rotary hearth furnace technology has the problems of low product metallization rate, high smelting energy consumption and no recovery of sensible heat of metallized pellets.
With the implementation of the policy of 'carbon peak reaching and carbon neutralization' in China, the reduction of the direct reduction carbon consumption of the rotary hearth furnace becomes the key point of the development of the rotary hearth furnace in the future. The first cooling section of the traditional rotary hearth furnace adopts water-cooled furnace top cooling, the cooling speed is low, and the cooled heat is not recovered.
Disclosure of Invention
In view of the above analysis, the present invention aims to provide an on-line cooling method for metallized pellets in a rotary hearth furnace, which solves the technical problems of low metallization rate, high carbon emission and no recovery of high-temperature sensible heat of metallized pellets in the direct reduction product of the traditional rotary hearth furnace.
The purpose of the invention is mainly realized by the following technical scheme:
the invention provides an online cooling device of a rotary hearth furnace, which is arranged on the rotary hearth furnace; the rotary hearth furnace comprises a reduction section, a first cooling section and a discharge end which are communicated in sequence;
the online cooling device comprises a hydrogen-rich gas generating unit and a hydrogen-rich gas conveying unit which are connected; the hydrogen-rich gas generating unit is used for providing hydrogen-rich gas;
a second cooling section is arranged between the reduction section and the first cooling section; a plurality of vertical flue gas baffles which are parallel to each other and have the same structure are arranged below the furnace top wall of the second cooling section, and a plurality of semicircular concave cavities are arranged at the bottom ends of the vertical flue gas baffles; the length direction of the vertical flue gas baffle is vertical to the material flowing direction;
the hydrogen-rich gas is conveyed to the first cooling section through the hydrogen-rich gas conveying unit after being generated by the hydrogen-rich gas generating unit, and the hydrogen-rich gas enters the second cooling section and the reduction section after cooling and deeply reducing the metallized pellets in the first cooling section.
In one possible design, the top of the reduction section is provided with a reduction section furnace top wall; the top of the first cooling section is provided with a first cooling section furnace top wall, and the top of the discharge end is provided with a discharge end furnace top wall; the distances from the furnace top wall of the reduction section, the furnace top wall of the first cooling section and the furnace top wall of the discharge end to the bottom of the rotary hearth furnace are sequentially reduced.
In one possible design, a three-way head is arranged on the conveying pipeline, a first end of the three-way head is communicated with the hydrogen-rich gas generating unit, a second end of the three-way head is connected with a first main pipe, and a third end of the three-way head is connected with a second main pipe; the first main pipe and the second main pipe are vertically arranged;
the first main pipe is provided with a plurality of first conveying branch pipes which are arranged in parallel and are vertical to the first main pipe; the second main pipe is provided with a plurality of second conveying branch pipes which are arranged in parallel and are vertical to the second main pipe, and the first conveying branch pipes are arranged below the second conveying branch pipes and are arranged in a staggered mode;
a plurality of first nozzles are arranged on the first conveying branch pipe; and the second conveying branch pipe is provided with a second nozzle, and the first nozzle and the second nozzle penetrate through the top wall of the first cooling section furnace.
In one possible design, the second nozzles are positioned at the gap between two adjacent first conveying branch pipes and are distributed at equal intervals with the two adjacent first nozzles on the first conveying branch pipes;
the first nozzle and the second nozzle can spray hydrogen-rich gas into the surface of the metallized pellets of the first cooling section.
In one possible design, the first nozzle and the second nozzle are both hollow tubular nozzles, one end of each hollow tubular nozzle, which is far away from the corresponding conveying branch pipe, is provided with a hemispherical spray head, the hemispherical spray head is provided with first spray holes which are annularly arranged and second spray holes which are positioned at the top end of the hemispherical spray head, and the diameter of each first spray hole is 1.0-1.5 times that of each second spray hole.
In one possible design, the hydrogen rich gas generation device includes a hydrogen rich gas tank, a pressurizer, a first hydrogen rich gas flow meter, and a first flow regulating valve;
the hydrogen-rich gas tank is connected with the conveying pipeline, and the pressurizer, the first hydrogen-rich gas flowmeter and the first flow regulating valve are sequentially arranged on the conveying pipeline.
In one possible design, the distance between the top wall of the discharge end and the furnace bottom is 5-20 cm.
In one possible design, the distance between the top wall and the bottom of the reduction section furnace is 10-200 cm.
In one possible design, the distance between the top wall and the bottom of the first cooling section furnace is 5-50 cm.
In one possible design, a screw discharger is provided at the discharge end of the rotary hearth furnace for discharging the cooled metallized pellets out of the rotary hearth furnace.
Compared with the prior art, the invention can realize at least one of the following beneficial effects:
(1) According to the on-line cooling device of the rotary hearth furnace, hydrogen-rich gas is directly sprayed to the surface of the metallized pellet instead of the water-cooled furnace wall of the first cooling section of the traditional rotary hearth furnace, the temperature of the metallized pellet to the first cooling section is 1100-1350 ℃, the hydrogen-rich gas is sprayed to the surface of the metallized pellet, the metallized pellet can be further reduced, the reduction rate of the metallized pellet is improved, the pellet metallization rate can be improved to more than 90%, and the product quality after direct reduction of the rotary hearth furnace is improved.
(2) In the on-line cooling device of the rotary hearth furnace, provided by the invention, hydrogen-rich gas is directly sprayed to the surface of the metallized pellet, so that the metallized pellet can be deeply reduced, the temperature of the metallized pellet can be reduced, the temperature of the metallized pellet is reduced from 1100-1350 ℃ to 700-1000 ℃, the discharging temperature of the pellet is reduced, and the service life of the spiral discharger is prolonged.
(3) In the on-line cooling device of the rotary hearth furnace, the hydrogen-rich gas conveying unit is used for directly blowing the hydrogen-rich gas to the surface of the metallized pellets, the temperature of the hydrogen-rich gas is improved while the temperature of the metallized pellets is reduced, the sensible heat of the high-temperature metallized pellets is recovered, the high-temperature hydrogen-rich gas enters the reduction section of the rotary hearth furnace to be combusted to provide heat for the reduction of the carbon-containing pellets, the direct reduction energy consumption of the rotary hearth furnace is reduced, the carbon emission of the rotary hearth furnace is reduced, and the efficient reduction of the pellets and the efficient utilization of the hydrogen-rich gas are cooperatively utilized.
In the invention, the technical schemes can be combined with each other to realize more preferable combination schemes. Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and drawings.
Drawings
The drawings, in which like reference numerals refer to like parts throughout, are for the purpose of illustrating particular embodiments only and are not to be considered limiting of the invention.
FIG. 1 is a view showing the structure of a first cooling zone of a rotary hearth furnace;
FIG. 2 is a flow diagram of a rotary hearth furnace hydrogen-rich reduction process;
FIG. 3 is a diagram showing the connection between the hydrogen-rich gas injection main pipe and the branch pipes;
FIG. 4 is a schematic view of the structure of a first nozzle provided in the first branch pipe;
fig. 5 is a schematic structural view of the first smoke barrier of the present invention.
Reference numerals:
1-bottom of rotary hearth furnace; 2-metallized pellets; 3-reduction section furnace top wall; 4-the first cooling section furnace top wall; 5-furnace top wall of discharge end; 6-a first manifold; 7-a second manifold; 8-a first delivery leg; 9-a second delivery branch; 10-a first nozzle; 11-a second nozzle; 12-a delivery conduit; 13-a first flow regulating valve; 14-a first hydrogen rich gas flow meter; 15-a hydrogen rich gas pressurizer; 16-a first nozzle hole; 17-a second nozzle; 18-a first smoke barrier; 19-a second smoke baffle; 20-a third smoke baffle; 21-a fourth smoke barrier; 22-a second cooling section; 23-a first cooling stage; 24-a spiral discharger; 25-semicircular cavities; 26-three way head.
Detailed Description
The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which form a part hereof, and which together with the embodiments of the invention serve to explain the principles of the invention and not to limit its scope.
The invention provides a rotary hearth furnace.A online cooling device is arranged on the rotary hearth furnace; the rotary hearth furnace comprises a feeding section (comprising a feeding hole), a reduction section, a first cooling section 23 and a discharging end which are sequentially communicated; the online cooling device comprises a hydrogen-rich gas generating unit and a hydrogen-rich gas conveying unit which are connected with each other; the hydrogen-rich gas generating unit is used for providing hydrogen-rich gas; the hydrogen-rich gas conveying unit comprises a conveying pipeline 12, and the conveying pipeline 12 is arranged at the top of the rotary hearth furnace and is communicated with a first cooling section 23 of the rotary hearth furnace; after the hydrogen-rich gas is generated by the hydrogen-rich gas generating unit, the hydrogen-rich gas is conveyed to the first cooling section 23 through the hydrogen-rich gas conveying unit, and the metallized pellets are cooled and deeply reduced by the hydrogen-rich gas in the first cooling section 23.
Specifically, as shown in fig. 1, fig. 2 and fig. 5, the on-line cooling device is arranged on the top of the rotary hearth furnace, and along the rotation direction of the bottom 1 of the rotary hearth furnace, the rotary hearth furnace comprises a feeding end, a reduction section (a reduction section 27 is arranged before pre-reduction, and the pre-reduction section is arranged conventionally, which is described in the present application), a first cooling section 23 and a discharging end which are communicated in sequence, the metallized pellets 2 enter the reduction section of the rotary hearth furnace through a feeder arranged at the feeding end, and form metallized pellets after reduction at the reduction section and enter the first cooling section 23; the hydrogen-rich gas generated by the hydrogen-rich gas unit is conveyed to the first cooling section 23 through the hydrogen-rich gas conveying unit and sprayed to the surface of the metallized pellet from the top of the first cooling section 23, the temperature of the hydrogen-rich gas is increased after the hydrogen-rich gas and the metallized pellet are subjected to heat exchange, the temperature of the metallized pellet is reduced, cooling is achieved, the metallized pellet 2 which is fully cooled by the hydrogen-rich gas is discharged out of the rotary hearth furnace through the discharge end, and online reduction and cooling of the metallized pellet 2 are achieved.
The cooling section of the traditional rotary hearth furnace adopts a water-cooled furnace top for cooling, the cooling speed is low, and the cooled heat is not recovered; compared with the prior art, the invention provides the method that hydrogen-rich gas is directly sprayed to the surface of the metallized pellet at the reduction section of the rotary hearth furnace, and on one hand, H in the hydrogen-rich gas is utilized 2 The high-temperature metallized pellet is quickly reduced, so that the metallization rate of the metallized pellet is further improved; on the other hand, the metallized pellets are cooled by utilizing the hydrogen-rich gas, and the cooled high-temperature hydrogen-rich gas provides heat for the reduction of the metallized pellets 2 in a reduction section in a combustion mode, so that the direct reduction energy consumption of the rotary hearth furnace is reduced.
In order to ensure that hydrogen-rich gas after heat exchange with metallized pellets can enter a reduction section, the top of the reduction section is provided with a reduction section furnace top wall 3; the top of the first cooling section 23 is provided with a cooling section furnace top wall 4, and the top of the discharge end is provided with a discharge end furnace top wall 5; the distances from the reduction section furnace top wall 3, the cooling section furnace top wall 4 and the discharge end furnace top wall 5 to the bottom 1 of the rotary hearth furnace are reduced in sequence.
Specifically, as shown in fig. 1, the height of the reduction section furnace top wall 3 from the furnace bottom is greater than the height of the cooling section furnace top wall 4 from the furnace bottom, and the height of the cooling section furnace top wall 4 from the furnace bottom is greater than the height of the discharge end furnace top wall 5 from the furnace bottom, so as to ensure that all hydrogen-rich gas after heat exchange with the metallized pellets enters the reduction section, thereby avoiding entering the discharge end; in addition, it should be noted that a flue is arranged on the top wall of the feeding section, a negative pressure fan is arranged outside the flue, the negative pressure generated by the negative pressure fan can pump out the flue gas (formed after the hydrogen-rich gas is further reduced and combusted) in the rotary hearth furnace, and meanwhile, the flow direction of the hydrogen-rich gas is ensured to be from the first cooling section 23 to the reduction section, so that the hydrogen-rich gas is prevented from entering the discharge end.
It should be noted that the rotary hearth furnace of the present invention includes a flue gas treatment unit, the flue gas treatment unit is connected to the negative pressure fan, and the flue gas sucked by the negative pressure fan enters the flue gas treatment unit. The flue gas treatment unit comprises a primary dust remover, a heat exchanger, a bag-type dust remover, a desulfurization tower, a denitration tower, an induced draft fan and a chimney; the flue gas treatment unit can recover and treat sensible heat, volatilized valuable metals, oxides thereof and dust in the flue gas.
In order to ensure that the hydrogen-rich gas sprayed to the surface of the metallized pellet is more uniform, the conveying pipeline 12 is provided with a tee joint 26, the first end of the tee joint 26 is communicated with the hydrogen-rich gas generating unit, the second end of the tee joint 26 is connected with a first main pipe 6, and the third end of the tee joint 26 is connected with a second main pipe 7; the first header pipe 6 is arranged perpendicular to the second header pipe 7; a plurality of first conveying branch pipes 8 which are arranged in parallel and are perpendicular to the first main pipe 6 are arranged on the first main pipe 6; the second header pipe 7 is provided with a plurality of second conveying branch pipes 9 which are arranged in parallel and are vertical to the second header pipe 7, and the first conveying branch pipes 8 are arranged below the second conveying branch pipes 9 and are arranged in a staggered manner; a plurality of first nozzles 10 are arranged on the first conveying branch pipe 8; and the second conveying branch pipe 9 is provided with a second nozzle 11, and the first nozzle 10 and the second nozzle 11 both penetrate through the cooling section furnace top wall 4.
Specifically, as shown in fig. 3, a plurality of first conveying branch pipes 8 arranged in parallel are arranged on the first main pipe 6, the first conveying branch pipes 8 are arranged at equal intervals, one end of each first conveying branch pipe 8 is communicated with the first main pipe 6, and all the first conveying branch pipes 8 are arranged perpendicular to the first main pipe 6; in addition, when explanation is needed, because the first conveying branch pipes 8 are located below the second conveying branch pipes 9, a transfer pipe is arranged between the three-way head and the second header pipe 7, one end of the transfer pipe is connected with the third end of the three-way head, the other end of the transfer pipe is connected with the second header pipe 7, the transfer pipe is arranged in the vertical direction, and the purpose of arranging the transfer pipe is to ensure that the second header pipe 7 is located above the first header pipe 6 in the spatial position, so that the second conveying branch pipes 9 arranged on the second header pipe 7 at equal intervals are located above the first conveying branch pipes 8, and the first conveying branch pipes 8 and the second conveying branch pipes 9 are arranged in a staggered manner; because the first conveying branch pipe 8 is provided with the plurality of first nozzles 10, the second conveying branch pipe 9 is provided with the second nozzles 11, and the first nozzles 10 and the second nozzles 11 penetrate through the cooling section furnace top wall 4, the first nozzles 10 and the second nozzles 11 are ensured to uniformly blow the hydrogen-rich gas to the surfaces of the metallized pellets.
Compared with the prior art, the invention can uniformly blow hydrogen-rich gas to the surface of the metallized pellets by arranging the first main pipe 6 and the second main pipe 7 vertically, arranging the plurality of first nozzles 10 on the first conveying branch pipe 8 and arranging the second nozzles 11 on the second conveying branch pipe 9, thereby realizing the rapid on-line cooling of the metallized pellets.
In order to further ensure that the hydrogen-rich gas is uniformly sprayed into the rotary hearth furnace and is fully contacted with the metallized pellets for heat exchange, the second nozzles 11 are positioned at the gap between two adjacent first conveying branch pipes 8 and are distributed at equal intervals with two adjacent first nozzles 10 on the first conveying branch pipes 8; the first nozzle 10 and the second nozzle 11 can spray hydrogen-rich gas into the surface of the metallized pellet 2 of the first cooling section 23, the metallized pellet is further reduced by the hydrogen-rich gas while the metallized pellet is cooled, the hydrogen-rich gas after the metallized pellet is cooled enters the reduction section, and heat is provided for the reduction of the metallized pellet 2 by the combustion of the hydrogen-rich gas in the reduction section.
In order to further increase the uniformity of hydrogen-rich gas injection, the first nozzle 10 and the second nozzle 11 have the same structure and are both hollow tubular nozzles, one end of each hollow tubular nozzle, which is far away from the corresponding conveying branch pipe, is provided with a hemispherical spray head, the hemispherical spray head is provided with a first spray hole 16 which is annularly arranged and a second spray hole 17 which is positioned at the top end of the hemispherical spray head, and the diameter of the first spray hole 16 is 1.0-1.5 times that of the second spray hole 17.
Illustratively, as shown in fig. 4, the hydrogen rich gas of the present invention enters the corresponding hemispherical head through the first delivery branch pipe 8 or the second delivery branch pipe 9, and since the gas pressure at the top end of the hemispherical head is higher than the gas pressure at other positions of the hemispherical head, the diameter of the first spray holes 16 is set to be 1.0 to 1.5 times the diameter of the second spray holes 17 in order to uniformly spray the hydrogen rich gas.
The hydrogen rich gas generation device of the present invention includes a hydrogen rich gas tank, a hydrogen rich gas pressurizer 15, a first hydrogen rich gas flow meter 14, and a first flow rate adjustment valve 13; the hydrogen rich gas tank is connected to the transfer line 12, and the hydrogen rich gas pressurizer 15, the first hydrogen rich gas flow meter 14, and the first flow rate regulating valve 13 are provided in this order on the transfer line 12.
The metallized pellets cooled by the on-line cooling device of the present invention are discharged from the rotary hearth furnace through the screw discharger 24 provided at the discharge end of the rotary hearth furnace.
Compared with the prior art, the online cooling device is utilized to directly blow hydrogen-rich gas to the surface of the metallized pellet, so that the metallized pellet can be deeply reduced, the temperature of the metallized pellet can be reduced, the temperature of the metallized pellet is reduced from 1100-1350 ℃ to 700-1000 ℃, the discharging temperature of the pellet is reduced, and the service life of the spiral discharger 24 is prolonged.
It should be noted that, in the present application, the distance between the top wall 3 of the reduction section and the furnace bottom is 10-200cm, and the distance is greater than the distance between the top wall 4 of the cooling section and the furnace bottom. The distance between the furnace top wall 3 and the furnace bottom of the reduction section is controlled within the range of 10-200cm, so that hydrogen-rich gas after heat exchange with the metallized pellets can enter the reduction section.
It should be noted that the distance between the cooling section top wall 4 and the furnace bottom is 5-50 cm. The spreading height of the metallized pellets 2 is 3-5cm, and the distance between the furnace top wall 4 and the furnace bottom of the cooling section is controlled within the range of 5-50cm, so that hydrogen-rich gas sprayed by the first nozzle 10 and the second nozzle 11 can be directly sprayed to the surfaces of the metallized pellets, and further, sufficient cooling is realized.
It should be noted that the distance between the top wall of the discharge end and the bottom of the furnace is 5-20 cm. The distance between the furnace top wall 5 and the furnace bottom at the discharge end is controlled within the range of 5-20cm, so that hydrogen-rich reducing gas after heat exchange with the metallized pellets can be prevented from entering the discharge end.
After the rotary hearth furnace feeding, in order to pave the mixtures (including metallized pellet 2 and carbon), be equipped with at the feed section of rotary hearth furnace and scrape the flitch, should scrape the both ends of flitch and fix respectively on the inside wall and the lateral wall of rotary hearth furnace, should scrape the flitch and can scrape the mixture that gets into the rotary hearth furnace and level.
It should be noted that, annular retaining walls are arranged on the inner side and the outer side of the rotary hearth furnace, and the height of the annular retaining walls is equal to the laying height of the metallized pellets 2 on the bottom of the rotary hearth furnace. The region that the stove bottom of inboard annular barricade, the annular barricade in the outside and rotary hearth furnace formed is the material and places the district, and inboard annular barricade and the annular barricade in the outside are used for preventing the material from arranging outward, can improve the charge capacity of material on the rotary hearth furnace bottom plate simultaneously.
In order to provide the throughput of the mixed materials and further improve the yield of the metallized pellets of the rotary hearth furnace, as shown in fig. 1 and 5 of the present invention, a second cooling section 22 is provided between the reduction section and the first cooling section 23 of the present invention; a plurality of vertical flue gas baffles arranged in parallel are arranged below the furnace top wall of the second cooling section, for example, four vertical flue gas baffles are arranged, namely a first vertical flue gas baffle 18, a second vertical flue gas baffle 19, a third vertical flue gas baffle 20 and a fourth vertical flue gas baffle 21, the vertical flue gas baffles are identical in structure and are rectangular steel plates, and a plurality of semicircular concave cavities 25 are arranged at the bottom ends of the first vertical flue gas baffle to the fourth vertical flue gas baffle.
Compared with the prior art, the vertical flue gas baffles arranged on the second cooling section 22 can increase the flow resistance of the hydrogen-rich gas in the first cooling section 23, so that the contact time of the hydrogen-rich gas and the metallized pellets is prolonged, and the deep reduction of the metallized pellets and the full cooling of the metallized pellets are realized.
It should be noted that a plurality of combustion nozzles are arranged on the inner furnace wall and the outer furnace wall of the reduction section, oxygen is injected into the rotary hearth furnace through the combustion nozzles, and necessary conditions are further provided for combustion of carbon in the mixture layer, the mixture is heated to a temperature required by direct reduction reaction through heat released by combustion of the carbon and unreacted hydrogen in the hydrogen-rich gas injected from the first cooling section and the second cooling section 22, and related valuable metal oxides in the mixture layer and the carbon are subjected to direct reduction reaction and are effectively recycled.
Example 1
The embodiment provides an on-line cooling device for metallized pellets of a rotary hearth furnace, which comprises a pressurizing machine, a first hydrogen-rich gas flowmeter 14, a first flow regulating valve 13, a conveying main pipe, conveying branch pipes, branch pipe nozzles, a first cooling section furnace top wall 4, a reduction section furnace top wall 3 and a discharge end top wall; the first conveying branch pipes 8 and the second conveying branch pipes 9 are uniformly and alternately distributed on the furnace top wall 4 of the first cooling section of the rotary hearth furnace, and a plurality of nozzles are distributed on each branch pipe, so that hydrogen-rich gas can be uniformly sprayed to the surface of metallized pellets at the bottom of the furnace, and the metallized pellets are deeply reduced and cooled. The distances from the first cooling section furnace top wall 4, the reduction section furnace top wall 3 and the discharge end top wall to the rotary hearth furnace bottom 1 are different, the distance from the discharge end top wall to the rotary hearth furnace bottom is small, the distance from the reduction section furnace top wall 3 to the rotary hearth furnace bottom is large, the resistance between the reduction section and the first cooling section is small, and hydrogen-rich gas can enter the reduction section from the first cooling section to provide heat for the reduction section.
The on-line cooling device for the metallized pellets of the rotary hearth furnace can uniformly spray hydrogen-rich gasThe high-temperature hydrogen-rich gas is blown to the surface of the high-temperature metallized pellet, the metallized pellet can be cooled while the hydrogen-rich gas is deeply reduced, and the high-temperature hydrogen-rich gas after cooling the metallized pellet enters a reduction section to be combusted to provide heat, so that the direct reduction energy consumption of the rotary hearth furnace is reduced. Pressurizing the hydrogen-rich gas to 2kPa by a pressurizer, and allowing the hydrogen-rich gas to enter a conveying pipeline 12 of the hydrogen-rich gas through a flowmeter and a first flow regulating valve 13, wherein the injection amount of the hydrogen-rich gas is 50m 3 And the hydrogen-rich gas enters the first main pipe 6 and the second main pipe 7 along the conveying pipeline 12 respectively, then enters the first conveying branch pipe 8 and the second conveying branch pipe 9, and is finally sprayed into the surface of the metallized pellet 2 of the first cooling section of the rotary hearth furnace through the first nozzle 10 on the first conveying branch pipe 8 and the second nozzle 11 on the second conveying branch pipe 9, so that the deep reduction and cooling of the high-temperature metallized pellet are realized. The distance between the furnace top wall 5 of the discharge end and the furnace bottom is 5cm, the distance between the furnace top wall 4 of the first cooling section and the furnace bottom is 10cm, and the distance between the furnace top wall 3 of the reduction section and the furnace bottom is 200cm. After the metallized pellets are reduced and cooled in the first cooling section by the hydrogen-rich gas, the hydrogen-rich gas enters the reduction section when the temperature reaches 800 ℃, and the hydrogen-rich gas is combusted in the reduction section to provide heat for the direct reduction of the carbon-containing pellets, so that the direct reduction energy consumption of the rotary hearth furnace is reduced. The embodiment improves the reduction degree of the metallized pellets through hydrogen-rich reduction, improves the cooling effect of the high-temperature metallized pellets, recovers the sensible heat of the metallized pellets, and reduces the coal gas consumption and carbon emission of the rotary hearth furnace.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention.
Claims (10)
1. The online cooling device of the rotary hearth furnace is characterized in that the online cooling device is arranged on the rotary hearth furnace; the rotary hearth furnace comprises a reduction section, a first cooling section and a discharge end which are sequentially communicated;
the online cooling device comprises a hydrogen-rich gas generation unit and a hydrogen-rich gas conveying unit which are connected with each other; the hydrogen-rich gas generation unit is used for providing hydrogen-rich gas;
the hydrogen-rich gas conveying unit comprises a conveying pipeline, and the conveying pipeline is arranged at the top of the rotary hearth furnace and is communicated with the first cooling section of the rotary hearth furnace;
a second cooling section is arranged between the reduction section and the first cooling section; a plurality of vertical flue gas baffles which are parallel to each other and have the same structure are arranged below the furnace top wall of the second cooling section, a plurality of semicircular concave cavities are arranged at the bottom ends of the vertical flue gas baffles, and the length direction of the vertical flue gas baffles is perpendicular to the material flowing direction;
the hydrogen-rich gas is conveyed to the first cooling section through the hydrogen-rich gas conveying unit after being generated by the hydrogen-rich gas generating unit, and the hydrogen-rich gas enters the second cooling section and the reduction section after being cooled and deeply reduced for the metallized pellets by the first cooling section.
2. The on-line cooling apparatus for a rotary hearth furnace according to claim 1, wherein a reduction-section furnace top wall is provided at the top of the reduction section; the top of the first cooling section is provided with a first cooling section furnace top wall, and the top of the discharge end is provided with a discharge end furnace top wall; the distances from the reduction section furnace top wall, the first cooling section furnace top wall and the discharge end furnace top wall to the bottom of the rotary hearth furnace are reduced in sequence.
3. The on-line cooling device of the rotary hearth furnace according to claim 2, wherein a three-way head is arranged on the conveying pipeline, a first end of the three-way head is communicated with the hydrogen-rich gas generating unit, a second end of the three-way head is connected with a first main pipe, and a third end of the three-way head is connected with a second main pipe; the first main pipe and the second main pipe are arranged vertically;
a plurality of first conveying branch pipes which are arranged in parallel and are perpendicular to the first main pipe are arranged on the first main pipe; the second main pipe is provided with a plurality of second conveying branch pipes which are arranged in parallel and are vertical to the second main pipe, the first conveying branch pipes are arranged below the second conveying branch pipes, and the first conveying branch pipes and the second conveying branch pipes are arranged in a staggered mode;
a plurality of first nozzles are arranged on the first conveying branch pipe; and the second conveying branch pipe is provided with a second nozzle, and the first nozzle and the second nozzle penetrate through the top wall of the first cooling section.
4. The on-line cooling apparatus for a rotary hearth furnace according to claim 3, wherein the second nozzles are located at a gap between two adjacent first transfer branch pipes and are equally spaced from the adjacent two first nozzles on the first transfer branch pipes;
the first nozzle and the second nozzle can spray hydrogen-rich gas into the surface of the metallized pellets of the first cooling section.
5. The on-line cooling apparatus of a rotary hearth furnace according to claim 4, wherein the first nozzle and the second nozzle are hollow tubular nozzles, a hemispherical head is provided at an end of the hollow tubular nozzle away from the corresponding delivery branch pipe, the hemispherical head is provided with a first nozzle hole arranged circumferentially and a second nozzle hole located at a top end of the hemispherical head, and a diameter of the first nozzle hole is 1.0 to 1.5 times a diameter of the second nozzle hole.
6. The on-line cooling apparatus for a rotary hearth furnace according to claim 1 or 5, wherein said hydrogen-rich gas generating means includes a hydrogen-rich gas tank, a pressurizer, a first hydrogen-rich gas flow meter, and a first flow regulating valve;
the hydrogen-rich gas tank is connected with the conveying pipeline, and the pressurizer, the first hydrogen-rich gas flowmeter and the first flow regulating valve are sequentially arranged on the conveying pipeline.
7. The on-line cooling apparatus for a rotary hearth furnace according to claim 6, wherein said discharge end top wall is spaced from the hearth by 5 to 20cm.
8. The on-line cooling apparatus for a rotary hearth furnace according to claim 2, wherein the distance between the top wall and the bottom of said reduction zone furnace is 10 to 200cm.
9. The on-line cooling apparatus of a rotary hearth furnace according to claim 3, wherein the distance between the top wall and the bottom of the first cooling zone is 5 to 50cm.
10. The on-line cooling device of the rotary hearth furnace according to any one of claims 2 to 9, wherein a spiral discharger is provided at a discharge end of the rotary hearth furnace, and the spiral discharger is used for discharging the cooled metallized pellets out of the rotary hearth furnace.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202221024639.XU CN217556219U (en) | 2022-04-29 | 2022-04-29 | Online cooling device of rotary hearth furnace |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202221024639.XU CN217556219U (en) | 2022-04-29 | 2022-04-29 | Online cooling device of rotary hearth furnace |
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