CN116026138A - Regenerative double chamber rotary kiln - Google Patents

Abstract

The application belongs to the technical field of chemical material production equipment, and particularly relates to a heat accumulating type double-hearth rotary kiln, which comprises a first rotary kiln hearth, a second rotary kiln hearth, a first preheating bin and a second preheating bin. According to the heat accumulating type double-hearth rotary kiln provided by the embodiment of the application, the high-temperature flue gas after calcination is utilized to preheat raw materials in the first preheating bin and the second preheating bin, so that the heat recycling of the high-temperature flue gas generated in the calcination process of the rotary kiln is realized, and the heat efficiency of the rotary kiln is greatly improved.

Description

Regenerative double chamber rotary kiln

technical field

The application belongs to the technical field of chemical material production equipment, in particular to a regenerative double-chamber rotary kiln.

Background technique

Rotary kiln refers to rotary rotary kiln, which belongs to building materials production equipment. Rotary kiln can be divided into cement kiln, metallurgical chemical kiln and lime kiln according to different materials. Lime rotary kiln is a widely used kiln for calcining small particle materials. It is suitable for steel, calcium carbide and non-ferrous metal production enterprises. It can directly calcinate 10-40mm fine-grained raw material limestone or dolomite. It has good raw material adaptability, It has the characteristics of large output, uniform product, high activity and stable production operation. Ordinary rotary kilns have poor energy efficiency in terms of waste heat reuse, resulting in low thermal efficiency of the entire rotary kiln system.

Contents of the invention

In view of this, the embodiment of the present application provides a regenerative double-chamber rotary kiln to solve the problem of low thermal efficiency of ordinary rotary kilns.

The embodiment of the present application provides a regenerative double chamber rotary kiln, including a first rotary kiln chamber, a second rotary kiln chamber, a first preheating chamber, a second preheating chamber and a transmission device; the first rotary kiln The chamber and the second rotary kiln chamber share the kiln head channel; the inner space of the first rotary kiln chamber and the second rotary kiln chamber communicate through the kiln head passage; in the first rotary kiln chamber and the second rotary kiln chamber The lower part of the chamber is respectively provided with corresponding transmission devices; the first preheating chamber communicates with the inner space of the first rotary kiln chamber through the corresponding unloading platform and the material inlet provided at the kiln tail of the first rotary kiln chamber; The second preheating chamber communicates with the inner space of the second rotary kiln chamber through the corresponding unloading platform and the material inlet arranged at the tail of the second rotary kiln chamber; A material outlet and a second material outlet; the first material outlet communicates with the inner space of the first rotary kiln; the second material outlet communicates with the inner space of the second rotary kiln; the second A material outlet and a second material outlet are respectively connected to the discharge equipment; a first kiln tail burner is set at the kiln tail of the first rotary kiln, and a first kiln head burner is set at the kiln head; The second kiln tail burner is set at the kiln tail of the two-rotary kiln chamber, and the second kiln head burner is set at the kiln head; the first preheating chamber and the second preheating chamber are respectively equipped with a plurality of plug-in burners .

Specifically, the regenerative double-chamber rotary kiln also includes a heat collecting cover; The outside of the warehouse and the discharge equipment; the heat collecting cover is a sealed heat collecting cover.

Specifically, when the regenerative double-chamber rotary kiln is used for calcining lime, the first preheating bin uses the high-temperature flue gas discharged from the second rotary kiln chamber to preheat materials, and the second preheating bin The high-temperature flue gas discharged from the first rotary kiln chamber is used to preheat materials.

Specifically, when the first rotary kiln chamber is in the calcining state and the second rotary kiln chamber is in the heat storage state, the low calorific value fuel is delivered to the plug-in burner in the first preheating chamber, and the low calorific value fuel is passed through the second A preheating chamber is preheated and enters the first rotary kiln together with the raw materials, where the raw materials are burned and calcined, and the flue gas after combustion passes through the first rotary kiln, the kiln head passage and the second rotary kiln in sequence chamber enters the second preheating chamber; when the second rotary kiln chamber is in the state of calcining and the first rotary kiln chamber is in the state of heat storage, low calorific value fuel is delivered to the plug-in burners in the second preheating chamber, and the After being preheated by the second preheating chamber, the fuel with low calorific value enters the second rotary kiln chamber together with the raw materials, where the raw materials are burned and calcined. The flue gas after combustion passes through the second rotary kiln chamber and the kiln head passage And the first rotary kiln chamber enters the first preheating chamber; the low calorific value fuel is a fuel with a calorific value less than or equal to 700 kcal/m ³ .

Specifically, the heat collecting cover is made of inner and outer thin plates, and filled with insulating materials such as rock wool or fiber blankets. There is an air duct in the heat collecting cover, and carbon dioxide and nitrogen are filled into the air duct in the heat collecting cover through the cooling fan of the heat collecting cover. Wait for the gas to cool the heat collection cover; the heated gas discharged from the heat collection cover enters the inner sleeve structure of the unloading platform, thereby cooling the metal parts of the unloading platform; the high-temperature gas discharged from the unloading platform is exchanged Preheat the fuel with low calorific value in the heater; seal the joints of the regenerative double-chamber rotary kiln; the ventilation pressure of the heat collecting cover is higher than the internal pressure of the first rotary kiln chamber and the second rotary kiln chamber , to prevent the gas from overflowing in the kiln; always use the lime cooling fan to input lime cooling air to the regenerative double-chamber rotary kiln to prevent the leakage of the reducing atmosphere in the flue gas; when the reducing atmosphere leaks, immediately turn on the lime cooling fan to spray into the air.

Specifically, thermal insulation materials are provided on the outer walls of the first preheating chamber and the second preheating chamber.

Specifically, the unloading platform adopts the unloading structure of diagonally discontinuous pushing materials; in order to ensure the service life of the unloading platform in the high temperature area, the unloading platform adopts an inner sleeve structure; the unloading platform includes bottom-up The supporting body, the supporting roller, the moving body, the lower steel plate and the upper steel plate are arranged in sequence; a plurality of supporting columns are arranged between the lower steel plate and the upper steel plate, and a cooling air channel is formed between the lower steel plate and the upper steel plate; the cooling air Refractory materials can be added inside and outside the channel, and the refractory materials can be brick masonry or pouring materials; refractory materials can be installed on the outer walls of the lower steel plate, upper steel plate and support column; Protective plate, the outer wall of the protective plate is provided with refractory materials; the unloading platform of the inner sleeve structure can allow the material to pass through, and the gas in the kiln can pass through in two directions; use other equipment with the same or similar functions to replace the unloading platform; Some or all components of the material platform can be cooled with heat transfer oil.

Specifically, the first rotary kiln chamber 1 and the second rotary kiln chamber 2 include, but are not limited to, swingable transmission devices.

Specifically, the regenerative double-chamber rotary kiln can use low calorific value fuel to calcinate lime, the rotation speeds of the first rotary kiln chamber and the second rotary kiln chamber can be the same or different, and the first rotary kiln chamber and the second rotary kiln chamber Materials with different particle sizes can be calcined, so that the production adaptability is better; fuels with the same or different calorific value are fed to different burners of the first rotary kiln and the second rotary kiln at different times.

The regenerative double-chamber rotary kiln provided in the embodiment of this application uses high-temperature flue gas to preheat the raw materials in the first preheating chamber and the second preheating chamber, and realizes the high-temperature flue gas generated during the calcination process of the rotary kiln. heat reuse. The regenerative double-chamber rotary kiln provided in the embodiment of this application uses two kiln bodies to alternately carry out calcination and heat storage, and fully utilizes the heat contained in the waste heat of flue gas to realize preheating of raw materials, which can reduce the temperature of exhaust gas in the entire kiln body system. To within 150 ℃, the thermal efficiency of the rotary kiln has been greatly improved, and the product performance and product adaptability have been improved. The regenerative double-chamber rotary kiln provided in the embodiment of the present application can use low calorific value fuel to calcinate lime, the rotation speeds of the two kiln chambers can be the same or different, and the two kiln chambers can calcinate materials with different particle sizes, thus making the production more adaptable good. Fuel with the same or different calorific value can be fed to different burners of the two kiln chambers at different times.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the accompanying drawings that need to be used in the descriptions of the embodiments or the prior art will be briefly introduced below. Obviously, the accompanying drawings in the following description are only for the present application For some embodiments, those of ordinary skill in the art can also obtain other drawings based on these drawings without paying creative efforts.

Fig. 1 is the top view of the regenerative double-chamber rotary kiln provided by the embodiment of the present application;

Fig. 2 is the front view of the regenerative double-chamber rotary kiln provided by the embodiment of the present application;

Fig. 3 is the structural representation of unloading platform;

Fig. 4 is the sectional view of A-A direction in Fig. 3;

Fig. 5 is a sectional view along B-B direction in Fig. 3 .

Among them: 1—the first rotary kiln chamber, 102—the first material outlet, 103—the first kiln tail burner, 2—the second rotary kiln chamber, 203—the second kiln tail burner, 3—the first preheating chamber , 4—second preheating chamber, 5—discharging equipment, 6—transmission device, 7—kiln head channel, 701—first kiln head burner, 702—second kiln head burner, 9—heat collecting cover, 10—unloading platform, 1001—supporting body, 1002—supporting roller, 1003—moving body, 1004—lower steel plate, 1005—upper steel plate, 1006—supporting column, 1007—cooling air channel, 1008—protective plate, 11—insert Type burner, 12—heat exchanger, 13—heat collecting cover cooling fan, 14—lime cooling fan.

Implementation

In the following description, specific details such as specific system structures and technologies are presented for the purpose of illustration rather than limitation, so as to thoroughly understand the embodiments of the present application. It will be apparent, however, to one skilled in the art that the present application may be practiced in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present application with unnecessary detail.

In order to illustrate the technical solutions described in this application, specific examples are used below to illustrate.

The embodiment of the present application provides a regenerative double-chamber rotary kiln for calcining lime. As shown in FIG. 1 , the regenerative double-chamber rotary kiln includes: a first rotary kiln chamber 1 , a second rotary kiln chamber 2 , a first preheating chamber 3 , a second preheating chamber 4 and a transmission device 6 .

The first rotary kiln chamber 1 and the second rotary kiln chamber 2 share the kiln head channel 7 . The inner space of the first rotary kiln chamber 1 and the inner space of the second rotary kiln chamber 2 are communicated through the kiln head channel 7 . A first material outlet 102 and a second material outlet are arranged below the kiln head channel 7 . The first material outlet 102 is connected to the first rotary kiln chamber 1 , and the second material outlet is connected to the second rotary kiln chamber 2 . Corresponding transmission devices 6 are respectively provided at the lower parts of the first rotary kiln chamber 1 and the second rotary kiln chamber 2 to drive each rotary kiln chamber to rotate. Alternatively, the first rotary kiln chamber 1 and the second rotary kiln chamber 2 include, but are not limited to, swingable transmission devices.

A first kiln tail burner 103 is set at the kiln tail of the first rotary kiln chamber 1, and a first kiln head burner 701 is set at the kiln head. A second kiln tail burner 203 is set at the kiln tail of the second rotary kiln chamber 2, and a second kiln head burner 702 is set at the kiln head. The first kiln head burner 701 faces the inner space of the first rotary kiln chamber 1 ; the second kiln head burner 702 faces the inner space of the second rotary kiln chamber 2 . A plurality of plug-in burners 11 are respectively arranged in the first preheating chamber 3 and the second preheating chamber 4 .

According to actual needs, hydrogen, natural gas, blast furnace gas, low calorific value gas and other combustible gases can be used as fuel for plug-in burners, kiln head burners and kiln tail burners, and solid fuels such as coal powder or gasoline can also be used. Liquid fuel, or a mixture of any two of gaseous, liquid, and solid fuels, or a mixture of gaseous, liquid, and solid fuels. The combustion-supporting gas can be air, oxygen-enriched gas or pure oxygen. When hydrogen is used as the fuel and air is used as the combustion-supporting gas, the gas operating in the inner space of the two kilns is a high-temperature mixed gas mainly consisting of nitrogen, water vapor and carbon dioxide. In this embodiment, 700 kcal blast furnace gas is selected as the fuel for the plug-in burner 10 .

The first preheating chamber 3 communicates with the inner space of the first rotary kiln chamber 1 through the corresponding unloading platform 10 and the material inlet provided at the kiln tail. The second preheating chamber 4 communicates with the inner space of the second rotary kiln chamber 2 through the corresponding unloading platform and the material inlet provided at the kiln tail.

In the regenerative double-chamber lime rotary kiln shown in Figure 1, the first preheating bin 3 uses the high-temperature flue gas discharged from the second rotary kiln chamber 2 to preheat the material, and the second preheating bin 4 uses the first rotary kiln chamber 1 The discharged high-temperature flue gas preheats the material.

A heat collecting cover 9 is arranged outside the first rotary kiln chamber 1 and the second rotary kiln chamber 2 to collect the heat released by the first rotary kiln chamber 1 and the second rotary kiln chamber 2 through the kiln shell. Corresponding heat collecting hoods are set outside the kiln head channel 7 between the first rotary kiln chamber 1 and the second rotary kiln chamber 2 to collect the flue gas lost through the kiln head channel during the flow between the two kiln bodies of heat. In the kiln head channel 7, only flue gas passes through, and no material passes through. Corresponding heat collecting covers 9 can be arranged outside the first preheating bin 3, the second preheating bin 4 and the discharge device 5, and can be arranged on the outer walls of the first preheating bin 3 and the second preheating bin 4 Insulation Materials. The heat collecting cover shall be a sealed heat collecting cover.

The operation process of the regenerative double-chamber lime rotary kiln provided in the embodiment of the present application is:

When the first rotary kiln chamber 1 is in the feed calcination stage and the second rotary kiln chamber 2 is in the heat storage stage, the preheated limestone from the roof of the first preheating chamber 3 is mixed with the air and the first preheating chamber 3 The low calorific value blast furnace gas ejected from each plug-in burner in the kiln enters the inner space of the first rotary kiln chamber 1 through the unloading platform 10 and the material inlet. Limestone enters from the kiln tail of the first rotary kiln chamber 1 together with air and low calorific value blast furnace gas, and the air and low calorific value blast furnace gas are preheated to 800° C. in the first preheating chamber 3 . Limestone is calcined while moving in the kiln chamber, and the final material travels to the kiln head. The calcined lime products run to the kiln head and are discharged from the first rotary kiln chamber 1 through the first material outlet 102 located below the kiln head channel 7 . The high-temperature lime discharged from the first rotary kiln chamber 1 enters the discharge device 5 through the first material outlet 102, and is cooled by the lime cooling fan 14 in the discharge device 5 with normal temperature air. The temperature of the air after cooling the lime rises and can be used as the combustion-supporting air for the first kiln head burner 701 and the second kiln head burner 702 . In the process of calcining limestone, a slightly excess amount of fuel can be fed into the first kiln tail burner 103, and most of the fuel is burned in the first kiln tail burner 103 to supplement the heat required for calcining lime; The gas diffuses to the vicinity of the first kiln head burner 701 and the second kiln head burner 702 , and supplementary combustion is carried out in the first kiln head burner 701 and the second kiln head burner 702 . Through the supplementary combustion of the first kiln head burner 701 and the second kiln head burner 702, the flue gas can be prevented from leaking from the kiln head. The above-mentioned combustion method can ensure the smooth circulation of flue gas between the two rotary kiln chambers, and the two kiln head burners for auxiliary calcination can form a reducing atmosphere in the rotary kiln in the heat storage state, which is beneficial to reduce The content of nitrogen oxides in the flue gas, thereby reducing or avoiding the subsequent denitrification treatment of the flue gas.

Inside the first rotary kiln chamber 1 , limestone decomposes under high temperature and releases a large amount of high-temperature CO ₂ . High-temperature _CO2 is mixed with high-temperature gas formed after fuel combustion to form high-temperature flue gas. The high-temperature flue gas enters the second rotary kiln chamber 2 from the first rotary kiln chamber 1 through the kiln head channel 7, and finally enters the second preheating chamber 4 to preheat the limestone cold material in the second preheating chamber 4. After preheating the limestone in the second preheating chamber 4, the temperature of the high-temperature flue gas is reduced to 150°C and can be directly discharged outside. In the second preheating bin 4, the limestone preheated by high-temperature flue gas preheats the low calorific value blast furnace gas injected from the plug-in burner of the second preheating bin 4, and the combustion-supporting air flows from the second preheating bin 4 The material inlet enters the second preheating bin 4, where the low calorific value blast furnace gas and combustion air can be preheated to 800°C in the second preheating bin 4, and enter the inner space of the second rotary kiln 2 together at the next beat.

After entering the next beat, the first preheating chamber 3 connected to the first rotary kiln chamber 1 is in the heat storage stage, and the second rotary kiln chamber 2 is in the feeding and calcining stage. The first rotary kiln 1 and the second rotary kiln 2 are alternately calcined or preheated, and the alternate operation is realized through the valves provided on the inlet and outlet of each material, and the time interval of the alternate operation is 10 minutes. In practical applications, the time interval of alternate operations can be freely adjusted as required.

It may not be possible to obtain a good calcination effect only by relying on the low calorific value blast furnace gas injected through the plug-in burner 10 for calcination. For this reason, the kiln tail burner and kiln head burner can be used to input fuel with higher calorific value or more blast furnace gas with low calorific value into the kiln chamber to supplement the heat required for calcination.

In this embodiment, 700kcal/ ^m blast furnace gas is used, 85% of the total air volume is fed into the kiln roof, and 30% of the blast furnace gas is fed into the plug-in burner 10, and the combustion air and blast furnace gas pass through the preheating chamber Finally, the temperature rises to 800°C, and then enters the rotary kiln. 60% blast furnace gas is fed into the kiln tail burner of the rotary kiln, and a flame is formed in the hearth of the rotary kiln to calcine the lime at a combustion temperature of 1350°C. The kiln head burner is fed with 3% blast furnace gas, so as to ensure that the gas and the lime cooling air accounting for 15% of the total air volume are fully burned in the rotary kiln, and there is no through-hole air in the whole system.

No matter in what state the lime cooling wind (air) should keep a certain amount to prevent the smoke from leaking from the ash outlet. If there is a reducing atmosphere when the flue gas is discharged, the kiln tail burner on the side of the regenerative kiln chamber should be supplemented with combustion to avoid the leakage of the reducing atmosphere. The heat collecting cover 9 is made of inner and outer thin plates, and filled with insulating materials such as rock wool or fiber blankets. The heat collecting cover 9 is provided with an air duct, which is filled with gases such as carbon dioxide and nitrogen to cool the heat collecting cover. The heated gas enters the inner sleeve structure of the unloading platform 10 after being discharged from the heat collecting cover, so as to cool the metal parts of the unloading platform 10 by wind. The high-temperature gas discharged from the unloading platform 10 preheats the low calorific value fuel in the heat exchanger 12 . Specifically, the unloading platform 10 discharges CO ₂ or N ₂ at 200°C, the CO ₂ or N ₂ at 200°C preheats the fuel with a low calorific value at room temperature in the heat exchanger 12, and the CO ₂ or N ₂ cools down to 50°C The heat exchanger 12 is discharged, and the heat exchanger 12 discharges the low calorific value fuel at 150°C. The plug-in burner 10, the kiln tail burner and the kiln head burner allow the low calorific value fuel of 150°C to enter the preheating chamber.

Seal each joint of the regenerative double-chamber rotary kiln. The ventilation pressure of the heat collecting cover 9 should be higher than the internal pressure of the first rotary kiln chamber 1 and the second rotary kiln chamber 2, so as to prevent the gas in the kiln from overflowing. The heat collecting cover shall be a sealed heat collecting cover.

As shown in FIG. 3 , FIG. 4 and FIG. 5 , the unloading platform 10 includes a support body 1001 , a support roller 1002 , a moving body 1003 , a lower steel plate 1004 and an upper steel plate 1005 arranged sequentially from bottom to top. A plurality of support columns 1006 are provided between the lower steel plate 1004 and the upper steel plate 1005 to form a fixed structure and separate the upper and lower steel plates. A cooling air passage 1007 is formed between the lower steel plate 1004 and the upper steel plate 1005 . Refractory materials can be added inside and outside the cooling air channel 1007, and the refractory materials can be brick masonry or pouring materials. The outer walls of the lower steel plate 1004, the upper steel plate 1005 and the support column 1006 can be provided with refractory materials. A protective plate 1008 is provided on the outer sides of the supporting body 1001, the supporting roller 1002, and the moving body 1003, and the outer wall of the protective plate 1008 is provided with a refractory material.

The supporting body 1001 is used to support the whole unloading platform. The lower steel plate 1004 and the upper steel plate 1005 are mainly used for load bearing, supporting the upper preheating bin and the raw materials in the preheating bin. The moving body 1003 can move linearly by using the supporting roller 1002 and its corresponding track, so that the unloading platform forms an opening for unloading. The supporting body 1001 and the moving body 1003 can be made of heat-resistant steel, such as I-beam. The support body 1001 and the protective plate 1008 provided on the outside of the moving body 1003 can form an air inlet channel and an air outlet channel with the I-beam. The protective plate 1008 provided outside the supporting roller 1002 can form an air duct. The cooling air passes through the moving body 1003 and the supporting roller 1002 in sequence, and finally is discharged from the supporting body 1001 . By continuously blowing cooling air to each air duct formed by the protective plate, the supporting body 1001, the supporting roller 1002 and the moving body 1003 can be effectively cooled by air, ensuring their normal operation in a high temperature environment.

The unloading platform 10 adopts the unloading structure of diagonally discontinuous pushing. In order to ensure the service life of the unloading platform in the high temperature area, the unloading platform 10 adopts an inner sleeve structure, and each air duct formed by the interlayer can protect the unloading platform from high temperature and improve the service life. The arrows in Fig. 3 to Fig. 5 show the flow direction of the cooling air in the interlayer of the unloading platform.

The unloading platform of the inner sleeve structure allows the material to pass through and the gas in the kiln to pass through in both directions. Other equipment with the same or similar functions can be used instead of the unloading platform. For part or all of the components that make up the unloading platform, heat transfer oil can be used for cooling.

The regenerative double-chamber rotary kiln provided in the embodiment of this application uses high-temperature flue gas to preheat the raw materials in the first preheating chamber and the second preheating chamber, and realizes the high-temperature flue gas generated during the calcination process of the rotary kiln. heat reuse. The regenerative double-chamber rotary kiln provided in the embodiment of this application uses two kiln bodies to alternately carry out calcination and heat storage, and fully utilizes the heat contained in the waste heat of flue gas to realize preheating of raw materials, which can reduce the temperature of exhaust gas in the entire kiln body system. To within 150 ℃, the thermal efficiency of the rotary kiln has been greatly improved, and the product performance and product adaptability have been improved. The regenerative double-chamber rotary kiln provided in the embodiment of the present application can use low calorific value fuel to calcinate lime, the rotation speeds of the two kiln chambers can be the same or different, and the two kiln chambers can calcinate materials with different particle sizes, thus making the production more adaptable good. Fuel with the same or different calorific value can be fed to different burners of the two kiln chambers at different times.

The above-described embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: it can still implement the foregoing embodiments Modifications to the technical solutions described in the examples, or equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the application, and should be included in the Within the protection scope of this application.

Claims (9)

1. A regenerative double-hearth rotary kiln, comprising: the device comprises a first rotary kiln chamber (1), a second rotary kiln chamber (2), a first preheating bin (3), a second preheating bin (4) and a transmission device (6);

the first rotary kiln chamber (1) and the second rotary kiln chamber (2) share a kiln head channel (7); the inner space of the first rotary kiln chamber (1) is communicated with the inner space of the second rotary kiln chamber (2) through a kiln head channel (7); corresponding transmission devices (6) are respectively arranged at the lower parts of the first rotary kiln chamber (1) and the second rotary kiln chamber (2);

the first preheating bin (3) is communicated with the inner space of the first rotary kiln chamber (1) through a corresponding discharging platform (10) and a material inlet arranged at the kiln tail of the first rotary kiln chamber (1); the second preheating bin (4) is communicated with the inner space of the second rotary kiln chamber (2) through a corresponding discharging platform and a material inlet arranged at the kiln tail of the second rotary kiln chamber (2);

a first material outlet (102) and a second material outlet are arranged below the kiln head channel (7); the first material outlet (102) is communicated with the inner space of the first rotary kiln chamber (1); the second material outlet is communicated with the inner space of the second rotary kiln chamber (2); the first material outlet (102) and the second material outlet are respectively connected with the discharging equipment (5);

a first kiln tail burner (103) is arranged at the kiln tail of the first rotary kiln chamber (1), and a first kiln head burner (701) is arranged at the kiln head; a second kiln tail burner (203) is arranged at the kiln tail of the second rotary kiln chamber (2), and a second kiln head burner (702) is arranged at the kiln head;

a plurality of inserted burners (11) are respectively arranged in the first preheating bin (3) and the second preheating bin (4).

2. A regenerative double-hearth rotary kiln according to claim 1, characterized by further comprising a heat-collecting hood (9); the heat collection cover (9) is arranged outside the first rotary kiln chamber (1), the second rotary kiln chamber (2), the first preheating bin (3), the second preheating bin (4) and the discharging equipment (5); the heat collecting cover (9) is a sealed heat collecting cover.

3. A regenerative double-hearth rotary kiln according to claim 1 or 2, characterized in that when the regenerative double-hearth rotary kiln is used for calcining lime, the first preheating bin (3) preheats material using high-temperature flue gas discharged from the second rotary kiln hearth (2), and the second preheating bin (4) preheats material using high-temperature flue gas discharged from the first rotary kiln hearth (1).

4. A regenerative double-hearth rotary kiln according to claim 3, characterized in that when the first rotary kiln hearth (1) is in a calcined state and the second rotary kiln hearth (2) is in a heat accumulating state, low-heat value fuel is conveyed to an inserted burner (11) in the first preheating bin (3), the low-heat value fuel enters the first rotary kiln hearth (1) together with raw materials after being preheated by the first preheating bin (3), the raw materials are combusted and calcined in the first rotary kiln hearth (1), and combusted flue gas enters the second preheating bin (4) through the first rotary kiln hearth (1), a kiln head channel (7) and the second rotary kiln hearth (2) in sequence; when the second rotary kiln chamber (2) is in a calcining state and the first rotary kiln chamber (1) is in a heat accumulating state, conveying low-heat-value fuel to an inserted burner in the second preheating bin (4), preheating the low-heat-value fuel by the second preheating bin (4), enabling the low-heat-value fuel to enter the second rotary kiln chamber (2) together with raw materials, combusting and calcining the raw materials in the second rotary kiln chamber (2), and enabling combusted flue gas to enter the first preheating bin (3) through the second rotary kiln chamber (2), a kiln head channel (7) and the first rotary kiln chamber (1) in sequence;

the low calorific value fuel has a calorific value of less than or equal to 700kcal/m ³ Is a fuel of (a).

5. A regenerative double-hearth rotary kiln according to claim 4, characterized in that the heat collecting cover (9) is made of inner and outer sheets and is filled with heat insulating materials such as rock wool or fiber blanket, an air duct is arranged in the heat collecting cover (9), and the air duct in the heat collecting cover (9) is filled with gases such as carbon dioxide, nitrogen and the like through the heat collecting cover cooling fan (13), so that the heat collecting cover (9) is cooled; the heated gas discharged by the heat collection cover (9) enters an inner sleeve structure of the discharging platform (10), so that the metal parts of the discharging platform (10) are cooled by wind; the high-temperature gas discharged by the discharging platform (10) preheats the low-heating-value fuel in the heat exchanger (12);

sealing each joint of the heat accumulating type double-hearth rotary kiln; the ventilation pressure of the heat collection cover (9) is higher than the internal pressure of the first rotary kiln chamber (1) and the second rotary kiln chamber (2), so that gas in the kiln is prevented from overflowing;

lime cooling air is always input into the heat accumulating type double-hearth rotary kiln by using a lime cooling fan (14) to prevent reducing atmosphere in flue gas from leaking; when the reducing atmosphere leaks, the lime cooling fan (14) is immediately started to spray air.

6. A regenerative double-hearth rotary kiln according to claim 5, characterized in that insulation materials are provided on the outer walls of the primary preheating bin (3) and the secondary preheating bin (4).

7. A regenerative double-hearth rotary kiln according to claim 6, characterized in that the discharge platform (10) adopts a diagonally intermittent pushing blanking structure; in order to ensure the service life of the discharging platform (10) in a high-temperature area, the discharging platform (10) adopts an inner sleeve structure; the discharging platform (10) comprises a supporting body (1001), a supporting roller (1002), a moving body (1003), a lower steel plate (1004) and an upper steel plate (1005) which are sequentially arranged from bottom to top; a plurality of support columns (1006) are arranged between the lower steel plate (1004) and the upper steel plate (1005), and a cooling air channel (1007) is formed between the lower steel plate (1004) and the upper steel plate (1005); the inside and outside of the cooling air channel (1007) can be added with refractory materials, and the refractory materials can be brick masonry or casting materials; the outer walls of the lower steel plate (1004), the upper steel plate (1005) and the support columns (1006) can be provided with refractory materials; a protection plate (1008) is arranged on the outer sides of the support body (1001), the support roller (1002) and the moving body (1003), and a refractory material is arranged on the outer wall of the protection plate (1008);

the discharging platform (10) with the inner sleeve structure can enable materials to pass through and enable gas in a kiln to pass through bidirectionally; replacing the discharge platform with other equipment with the same or similar functions; for some or all of the components that make up the discharge platform, the cooling may be performed using a thermally conductive oil.

8. A regenerative double-bore rotary kiln according to claim 7, wherein the first and second rotary kiln bores 1 and 2 include, but are not limited to, a rocking-capable transmission.

9. A regenerative double-hearth rotary kiln according to any one of claims 1 to 8, characterized in that lime can be calcined using low heating value fuel, the rotation speeds of the first rotary kiln hearth (1) and the second rotary kiln hearth (2) can be the same or different, and the first rotary kiln hearth (1) and the second rotary kiln hearth (2) can calcine materials with different particle sizes, so that the production adaptability is better; different burners of the first rotary kiln chamber (1) and the second rotary kiln chamber (2) are fed with fuels of the same or different heat values at different times.

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