CN116659249A

CN116659249A - External channel supporting type double-chamber lime kiln for mixing and blowing and production method

Info

Publication number: CN116659249A
Application number: CN202310723255.XA
Authority: CN
Inventors: 刘玉泉; 刘久盛
Original assignee: Tangshan Jinquan Metallurgical Technology Industry Co ltd
Current assignee: Tangshan Jinquan Metallurgical Technology Industry Co ltd
Priority date: 2023-06-19
Filing date: 2023-06-19
Publication date: 2023-08-29

Abstract

The application discloses a dual-purpose kiln external channel supporting type double-chamber lime kiln and a production method thereof, wherein an extended furnace body structure is adopted, an external circulating flue, an external flue type inclined supporting structure, a detachable spray gun, a flue ash removal pneumatic conveying device, a kiln top waste gas waste heat drying screening and spinning suspension preheater, a constant-temperature calcination reaction kettle, an electromagnetic induction heating temperature regulating device and the like are arranged on a kiln body, so that the production function conversion of a single-chamber vertical kiln and a dual-chamber vertical kiln can be realized, the mixing type production can be independently carried out by using massive solid fuel, the double-chamber heat storage and the injection of powdered fuel such as coal, biomass and the like and gas fuel can be realized, meanwhile, the problems of structural defects, production defects and potential safety hazards caused by arranging a bracket type supporting and hanging cylinder structure in the kiln of the traditional double-chamber kiln are solved; the proposal provided by the application is a great innovation and technical improvement of the traditional lime kiln structure and lime production mode.

Description

External channel supporting type double-chamber lime kiln for mixing and blowing and production method

Technical Field

The application relates to the technical field of industrial shaft kilns, in particular to a lime kiln for producing lime, and specifically relates to an external-kiln channel supporting type double-chamber lime kiln capable of realizing dual purposes of mixing and blowing, and a production method for producing lime by using the lime kiln.

Background

Lime is produced mainly through a shaft kiln process, the shaft kiln process is divided into a single-chamber shaft kiln and a double-chamber shaft kiln, and the fuel structure of the single-chamber shaft kiln is a mixed material type production process adopting solid blocky coal or mixed combustion of coke fuel and stone, and the production process cannot use powdered fuel such as coal dust and the like for production. The double-chamber lime kiln can realize the injection of coal powder fuel and gas fuel, but is limited by the process and cannot be produced by using massive solid fuel.

The existing single-hearth mixed lime shaft kiln has the defects that the variety of the selected fuel is single due to the limitation of a process structure, high-quality massive anthracite and massive coke with high price can only be used, and low-price fuels with high volatility such as bituminous coal, lignite, gas coal and the like can not be used, so that the process has high fuel cost and poor quality of lime products. In addition, the single-chamber shaft kiln can not realize the heat storage function, so that the fuel energy consumption is always higher than that of other kiln types. More importantly, along with the development of economy and society, china has gradually eliminated and banned the construction of single-chamber lime kilns adopting solid traditional fossil energy fuels such as coal, so that how to change and promote the production process of the traditional single-chamber mixed-material type vertical kiln, reduce the production cost of the fuel, improve the product quality and promote the transformation and generation of the selection of lime fuel for coal production has important significance for realizing the green and carbon reduction upgrading of the lime industry and solving the industry common bottleneck.

Parallel flow heat accumulating type double-chamber lime kiln is widely popularized worldwide due to the unique energy saving advantage, and the double-chamber lime shaft kiln has been developed for more than 60 years so far. The parallel-flow heat-accumulating type double-hearth lime kiln has a unique double-hearth structure, and the two kiln hearths can alternately realize the calcining and heat accumulating functions, so that the highest lime activity and the lowest fuel consumption can be realized. Therefore, the method has the technical advantages which are incomparable with other lime kilns, and especially can be used for producing powdery fuels such as high-volatility bituminous coal, lignite, gas coal and the like.

At present, two types of double-chamber shaft kilns are commonly used at home and abroad: bracket type structure and suspension cylinder type structure. The bracket supporting structure of the bracket type double-hearth kiln structure is arranged at the lower part of the calcining zone inside the kiln body, and the weight of the kiln body of the whole kiln body and the preheating zone are supported by arranging a plurality of bracket type columns made of refractory materials.

Firstly, due to the limiting characteristic of the bracket type structure, the structure has the following defects:

1. because the bracket column feet are arranged in the furnace, a plurality of dead angles are generated between the bracket column feet, so that air cannot circulate, the gas circulation atmosphere in the kiln is poor, and the combustion and cooling effects in the kiln are affected;

2. The bracket supporting part, the arch bridge part and the channel middle layer refractory material in the kiln are easy to collapse due to temperature fluctuation influence caused by material extrusion or repeated impact of cold air;

3. the fume circulation channel has serious dust accumulation, the dust accumulation is easy to form scabs, knots and other materials which are difficult to treat, and the production of the materials needs to be stopped periodically to remove the dust manually and the knots; further, because the flue gas channel is arranged in the kiln, construction and maintenance are extremely difficult;

4. the refractory material has the advantages of complex structure, high manufacturing requirement, high construction difficulty, large usage amount and high investment cost.

(II) the double-hearth kiln suspension cylinder structure as the second generation technology overcomes a part of the defects compared with the bracket type support structure, but the prior suspension cylinder technology also has the following defects:

1. the suspended cylinder double-chamber kiln has a complex structure, and the suspended cylinder part bearing two thirds of the kiln body weight is required to be manufactured by integral special heat-resistant steel materials, so that the manufacturing requirement is high, the manufacturing difficulty is high and the manufacturing cost is high;

2. the hanging type fixing structure of the hanging cylinder has the advantages that the maintenance difficulty is high, the accident risk is high, once the problem is difficult to repair, the serious person can even have an integral slump phenomenon;

3. The suspension cylinder needs to be cooled by the air supply of an independent fan, so that the power consumption is increased, and the cylinder body is easy to form over-temperature when power failure and fan failure occur, so that the whole operation life of the suspension cylinder is influenced; the structure is burnt out when cooling wind is absent for a long time, so that the cylinder body is extremely easy to damage and the whole collapse accident is caused;

4. the suspension ring on the suspension cylinder is required to adopt refractory castable, and meanwhile, the site casting is required to support the template, maintain, demold and bake, so that the construction difficulty and the construction period are obviously increased.

It can be seen that the thermal conditions in the kiln of the conventional double-chamber kiln need to be further improved.

The thermodynamic principle of the lime calcination in the double-chamber lime kiln is that the thermodynamic system of the shaft kiln is directly determined by the gas flow distribution condition in the kiln through solid phase and gas phase heat exchange among gaps and airflows of stone particles, and the air permeability in the kiln is determined by the cleanliness and the block ratio of limestone entering the kiln. If stones are not screened and cleaned, dust and powder ash are generated in the kiln body due to the fact that the stones are not cleaned, or wet stones in rainy seasons are adhered to soil, so that a kiln flue gas circulation channel is easy to block, air flow is not communicated, the temperatures of two kiln bores are unbalanced, and the quality of finished product ash is directly affected; moreover, the channel is easy to be blocked after a period of production, the air flow pressure of the kiln body is influenced, manual cleaning is needed, time and labor are wasted, safety is not ensured, the yield is also influenced, the damage to refractory bricks is larger, and the service life of the refractory materials is seriously influenced.

In the lime production mode, whether a single-hearth mixed kiln, a double-hearth kiln or a rotary kiln, the problems of narrow application range of raw material stones exist in the lime kiln types, the limestone granularity range used in the lime shaft kiln is 60-120 mm, and the limestone granularity range used in the rotary kiln is 20-40 mm. A large amount of small-grain limestone with a grain size of less than 20mm is sold as stone slag at a low price, resulting in great waste of mineral resources and an increase in stone mining costs.

The lime production mode is now developing towards energy conservation and comprehensive utilization of waste. Therefore, how to burn the offcut screen lower product of limestone used by the lime calciner into quicklime, reduces the production cost of enterprises, generates greater economic benefit and avoids the environmental protection problem caused by the discarding of the offcut screen lower product, and is the target of each lime factory.

Therefore, based on the current situation of the double-hearth lime kiln, how to solve the defects of the traditional double-hearth shaft kiln; how to organically combine the structural characteristics of the mixed-combustion single-chamber shaft kiln with the structural characteristics of the double-chamber lime kiln, so as to realize the fusion of two kiln type production modes and achieve fuel diversity and functional diversity; how to reform traditional compounding formula single chamber vertical kiln into two chamber kiln, realize single chamber kiln product upgrading synergy to and how to burn the lime of lime calcination kiln the offcut sieve of lime stone that uses down, realize energy-concerving and environment-protective while reducing manufacturing cost, be the technical problem who needs to solve at present.

Disclosure of Invention

The application provides an external channel supporting type double-chamber lime kiln for mixing and blowing, which is used for solving the problems of high production cost and relatively low lime production quality of the traditional lime kiln.

In order to achieve the above object, the present application provides the following technical solutions:

in one aspect, the application provides an external-kiln channel supporting type double-chamber lime kiln for mixing and blowing, which comprises two adjacent vertical kilns, wherein each vertical kiln comprises a kiln body, the kiln body is provided with a kiln top, a kiln bottom, a kiln wall and a kiln chamber, and a preheating zone, a calcining zone and a cooling zone are formed in each kiln chamber from top to bottom; the preheating zone and the calcining zone are both of straight cylinder type structures, and the cooling zone is of extended right cone type structure;

kiln top combustion air conversion valves, kiln top waste gas conversion valves, two-stage sealing feeding devices and lifting rotary composite distributing devices are arranged on the two kiln tops;

a plurality of detachable spray guns which are annularly arranged are arranged on the two kiln walls, and the outlets of the detachable spray guns are arranged at the joint part of the bottom of the preheating zone and the upper part of the calcining zone;

an external annular smoke circulation channel is arranged outside the kiln body at the lower part of each calcining zone, and a flue control valve is arranged at the tangential position between the external annular smoke circulation channels on the two kiln bodies;

A combustion-supporting air cap is arranged in each kiln chamber,

each kiln bottom is provided with a mineral discharging system and an ash discharging system, the mineral discharging system is used for conveying cooled calcium oxide to the ash discharging system, and the ash discharging system is used for discharging the calcium oxide out of the kiln.

In the technical scheme, the kiln top waste gas conversion valve is connected with an external dust remover pipeline, and the two-stage sealing feeding device and the lifting rotary composite distributing device are used for conveying mixed stone and blocky coal into the kiln; the lifting rotary composite distributor is provided with a mechanical arm type distributor which is used for arranging large-particle stones in the center of the kiln and small-particle stones at the periphery of the kiln wall.

Further, kiln top external air inlet pipeline valves are arranged on the two kiln tops.

Further, a chute type material scattering channel is also arranged on the lifting rotary composite distributing device.

Further, each kiln top is provided with a buffer bin which is used for receiving stones conveyed by an external elevator, and a kiln top fixed screening device and a preheating and drying device are arranged in the buffer bin of the kiln top; the kiln top fixed screening device is used for carrying out secondary screening on stones, the lower part of the kiln top fixed screening device is connected with an undersize material collecting bin, the outlet of the undersize material collecting bin is connected with a composite crushing device, the outlet of the composite crushing device is connected with a single-cylinder spinning suspension preheater, the outlet of the single-cylinder spinning suspension preheater is connected with a powder suspension calcination channel, and a plurality of baffle plates are arranged in the powder suspension calcination channel; the outlet of the powder suspension calcination channel is connected with a double-cylinder spinning suspension preheater, the outlet of the double-cylinder spinning suspension preheater is connected with a constant-temperature calcination reaction kettle, the constant-temperature calcination reaction kettle is connected with an exhaust gas outlet pipe of a powder release bin, and the constant-temperature calcination reaction kettle carries out constant-temperature flash calcination on lime powder through high-temperature exhaust gas fed into the constant-temperature calcination reaction kettle to decompose the lime powder into active lime.

Further, an electromagnetic induction heating temperature regulating device is arranged on the exhaust gas outlet pipe of the powder releasing bin and is used for heating the exhaust gas discharged from the powder releasing bin to a set temperature, and the exhaust gas heated to the set temperature is sent into the constant temperature calcination reaction kettle.

Further, the external annular flue gas circulation channel is fixed on the kiln wall through an inclined flue type supporting structure arranged below the external annular flue gas circulation channel, the inclined flue type supporting structure is an external flue type inclined supporting channel, and a plurality of external flue type inclined supporting channels are communicated with the external annular flue gas circulation channel.

Further, the external annular flue gas circulation channel is communicated with the powder suspension calcination channel through a flue gas circulation channel pressure-regulating release valve.

Further, a circulating flue ash collection bin is arranged between the two external flue type inclined support channels, the lower outlet of the circulating flue ash collection bin is communicated with an annular ash removal pneumatic conveying pipeline, and a pulse ash discharge valve is arranged on the pipeline for connecting the circulating flue ash collection bin and the annular ash removal pneumatic conveying pipeline.

Further, the annular ash removal pneumatic conveying pipeline is connected with an ash removal pneumatic conveying external pipeline, and the ash removal pneumatic conveying external pipeline is connected with a powder release bin; the powder release bin is internally provided with a cyclone dust removal and filtration device which is used for separating dust and smoke; the separated dust descends to the lower ash hopper, and the separated flue gas ascends to enter the powder suspension calcination channel through the pressure release adjusting device.

Further, the annular ash removal pneumatic conveying pipeline is connected with an ash removal pneumatic conveying internal connecting pipeline, and the ash removal pneumatic conveying internal connecting pipeline is used for discharging dust materials to the outside of the kiln.

Further, the ore discharging system comprises a plurality of peripheral discharging devices which are uniformly distributed according to the circumferential direction of the kiln wall, and a central discharging device which is arranged at the center of the plurality of peripheral discharging devices.

Further, the ash discharging system comprises a directional rotation ash discharging device and a metering device, wherein the blanking pipe of the peripheral discharging device and the blanking pipe of the central discharging device are communicated with the directional rotation ash discharging device, and the directional rotation ash discharging device is used for discharging calcium oxide into the metering devices; the metering device is connected with a furnace bottom ash discharging bin, the furnace bottom ash discharging bin is connected with a multi-stage sealing discharger, and the multi-stage sealing discharger is used for discharging the calcium oxide discharged in a metering mode out of the kiln body.

Further, the inner diameter of the kiln chamber gradually expands from the bottom of the calcining zone to the bottom of the cooling zone.

Further, each kiln bottom is provided with an air inlet, and a kiln bottom cooling air conversion valve is arranged on the air inlet.

Further, a combustion-supporting air cap is arranged in each kiln chamber, is positioned at the bottom of the kiln and is positioned above the ore discharging system.

On the other hand, the application provides a production method for producing lime by the external-kiln channel supporting type double-chamber lime kiln with dual purposes of mixing and blowing.

In the above technical scheme, the flue control valve is closed to realize the mixed material type production process, which specifically comprises the following steps:

s1: closing a flue control valve to enable each kiln chamber to form an independent flue gas circulation system, closing a kiln top combustion air conversion valve of any vertical kiln, opening a kiln top waste gas conversion valve, and forming negative pressure in the kiln chamber;

s2: the mixture of stone and massive coal is conveyed into the kiln by a two-stage sealing feeding device and a lifting rotary composite distributing device;

s3: when the material in the kiln descends to the position of the calcining zone, combustion air from the combustion-supporting air cap combusts with fuel in stone, and CO in the stone ₂ Decomposing to form calcium oxide;

s4: when the calcium oxide continuously descends to the lower part of the calcining zone, heat exchange and cooling are carried out on the calcium oxide and the combustion air from the bottom of the kiln, and the combustion air after heat exchange continuously ascends to the calcining zone to participate in combustion; after the burnt waste gas passes through the preheating zone to exchange heat with stone, the temperature of the waste gas is reduced, and the waste gas is discharged out of the kiln through a kiln top waste gas conversion valve;

S5: after the calcium oxide continuously descends to the lower space of the combustion-supporting air hood at the bottom of the kiln, the whole cooling process is completed, and then the calcium oxide sequentially enters the ore discharging system and the ash discharging system and is discharged out of the kiln through the ash discharging system.

Further, two shaft kilns are respectively denoted as a shaft kiln and a shaft kiln B, the kiln chamber of the shaft kiln A is denoted as a chamber A, and the kiln chamber of the shaft kiln B is denoted as a chamber B; the flue control valve is opened to realize the production process of coal dust injection and gas fuel, and the method specifically comprises the following steps:

s1: opening a flue control valve to enable waste gas of the chamber A and the chamber B to circulate mutually;

s2: opening a combustion air conversion valve at the top of the shaft kiln A, and blowing high-pressure combustion air into a preheating zone of the shaft kiln A to enable the calcining zone to be in a positive pressure state;

s3: powder coal fuel or gas fuel is conveyed into the chamber A through a detachable spray gun, so that the powder coal fuel or gas fuel is mixed with high-pressure combustion air from top to bottom to form hot combustion flame, the combustion flame penetrates through the calcining zone to form a high-temperature area of the calcining zone, stone is subjected to heat exchange in the high-temperature area of the calcining zone, and the flame and the stone move in the same direction in the heat exchange process to finish the parallel-flow calcining process; during this process the stone breaks down to form calcium oxide;

s4: slowly lowering calcium oxide to the position of the external annular smoke circulation channel, converging with countercurrent cooling air from bottom to top generated by a combustion-supporting air cap at the bottom of the kiln, and forming positive pressure airflow, wherein the converged airflow flows to the external annular smoke circulation channel;

S5: and in the same time period when the bore A completes the operation steps S1 to S4, the bore B carries out the following steps: closing a combustion air conversion valve at the kiln top; stopping the fuel supply to the removable lance thereon; opening a kiln top waste gas conversion valve to be connected with an external dust remover pipeline, and enabling the whole B chamber to form a negative pressure heat storage state under the action of the external dust remover; because of the pressure difference between the A chamber and the B chamber, the high-temperature waste heat flue gas in the external annular flue gas circulation channel of the A shaft kiln quickly flows into the B chamber and is converged with the high-pressure combustion air of the B chamber to form a new positive-pressure air flow, so that the high-temperature waste gas of the A chamber and stone of the B chamber penetrate through the whole calcining zone and the preheating zone from bottom to top to perform full heat exchange, and the countercurrent heat storage is completed; the flue gas after heat accumulation is discharged out of the kiln through a kiln top waste gas conversion valve and enters an external dust remover;

in the operation steps, reversing time lengths of the chamber A and the chamber B are set manually, the chamber A and the chamber B are subjected to reversing calcination according to the set reversing time lengths, and the operation steps are repeated.

Furthermore, the suspension type powder lime calcining process can be realized under both the mixed material type production process and the coal powder injection and gas fuel production process, and the suspension type powder lime calcining process comprises the following steps: a buffer bin is arranged at each kiln top, a kiln top fixed screening device and a preheating and drying device are arranged in the buffer bin, the kiln top fixed screening device is connected with a composite crushing device, the outlet of the composite crushing device is connected with a single-cylinder spinning suspension preheater, the outlet of the single-cylinder spinning suspension preheater is connected with a powder suspension calcination channel, the powder suspension calcination channel is connected with a double-cylinder spinning suspension preheater, the outlet of the double-cylinder spinning suspension preheater is connected with a constant temperature calcination reaction kettle, the constant temperature calcination reaction kettle is connected with an exhaust gas outlet pipe of a powder release bin, and an electromagnetic induction heating temperature regulating device is arranged on the exhaust gas outlet pipe of the powder release bin;

Crushing the screened stone powder and coal particle fuel to the target particle size of suspension calcination by a composite crushing device;

the crushed stone and fuel mixed powder sequentially enter a single-cylinder spinning suspension preheater and a double-cylinder spinning suspension preheater through a powder suspension calcination channel, finally enter the constant-temperature calcination reaction kettle, and are decomposed and calcined with waste gas from a powder release bin to generate active lime.

Compared with the prior art, the application has the following beneficial effects:

the application provides an external-kiln channel supporting type double-chamber lime kiln for mixing and blowing, wherein a flue control valve is arranged in a flue between two kiln chambers, so that the opening and closing of waste heat flue gas between the two kiln chambers are realized, and the independent production function of a single-chamber kiln in mixed material production and the heat storage function of the intercommunication of two kiln body flue gas in double-chamber heat storage production are realized; the detachable spray gun is arranged, so that the process adjustment is convenient when different fuel structures are adopted; the external passage supporting type double-chamber lime kiln provided by the application changes the production mode that the traditional single-chamber mixing type lime shaft kiln can only use solid fuels such as single blocky anthracite or coke, and can use powdery bituminous coal and biomass powder fuel with low injection price, thereby reducing the cost and realizing the benefit improvement; the external annular flue gas circulation channel arranged on the kiln body is more reasonable and safer in structure, the kiln inner cooling belt is of an expanded right circular cone structure, the trend of waste heat flue gas flow of the calcining belt and the cooling belt is more reasonable, and the material cooling time of the cooling belt is more sufficient and the lime activity is higher.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art. It should be understood that the specific shape and configuration shown in the drawings are not generally considered limiting conditions in carrying out the application; for example, those skilled in the art will be able to make routine adjustments or further optimizations for the addition/subtraction/attribution division, specific shapes, positional relationships, connection modes, dimensional proportion relationships, and the like of certain units (components) based on the technical concepts and the exemplary drawings disclosed in the present application.

FIG. 1 is a schematic structural view of a corbel-type double-hearth kiln;

FIG. 2 is a schematic view of a structure of a suspension cylinder type double-chamber kiln;

FIG. 3 is a schematic structural diagram of an external channel supported double-chamber lime kiln according to an embodiment of the application, wherein arrows in the diagram represent airflow directions when the external channel supported double-chamber lime kiln is used for carrying out a mixed material production process;

FIG. 4 is an illustration of a partial view taken from the upper portion of FIG. 3;

FIG. 5 is an illustration of a partial view taken from the middle of FIG. 3;

FIG. 6 is an illustration of a partial view taken from the lower portion of FIG. 3;

FIG. 7 is a schematic diagram of the structural principle of an external-kiln channel supported double-chamber lime kiln according to another embodiment of the application, wherein arrows in the diagram indicate the trend of air flow when the external-kiln channel supported double-chamber lime kiln is used for carrying out coal dust injection and gas fuel production processes;

FIG. 8 is an illustration of a partial view taken from the upper portion of FIG. 7;

FIG. 9 is an illustration of a partial view taken from the middle of FIG. 7;

FIG. 10 is an illustration of a partial view taken from the lower portion of FIG. 7;

FIG. 11 is a schematic diagram of an annular ash removal pneumatic conveying pipeline and a part of structures related to the annular ash removal pneumatic conveying pipeline arranged on an external kiln channel supporting type double-chamber lime kiln in an embodiment.

Reference numerals illustrate:

1. a kiln top combustion air conversion valve; 2. a kiln top waste gas conversion valve; 3. a two-stage sealed feeding device; 4. lifting and rotating the composite distributing device; 4-1, a manipulator type distributor; 4-2, a chute type material scattering channel; 5. a detachable spray gun; 6. an external annular smoke circulation channel; 7. an external flue type inclined support channel; 8. a flue control valve; 9. an ash collection bin of the circulating flue; 10. a pulse type ash valve; 11. annular ash removal pneumatic conveying pipeline; 12. ash removing pneumatic conveying external pipeline; 13. ash removing pneumatic conveying internal connecting pipeline; 14. a combustion-supporting air cap; 15. peripheral discharging devices; 16. a central discharge device; 17. a directional rotation ash discharging device; 18. a metering device; 19. a multistage seal discharger; 20. an exhaust gas enclosure; 21. buffering bin; 22. a screening device is fixed at the kiln top; 23. a undersize collection bin; 24. a pressure regulating release valve of the smoke circulation channel; 25. a powder suspension calcination channel; 25-1, baffles; 26. a composite crushing device; 27. a single-cylinder spinning suspension preheater; 28. a powder release bin; 29. a pressure release adjustment device; 30. an exhaust branch pipe; 31. a double-cylinder spinning suspension preheater; 32. calcining the reaction kettle at constant temperature; 33. an electromagnetic induction heating temperature regulating device; 34. a flue gas nozzle I; 35. and a flue gas nozzle II.

Detailed Description

The application will be further described in detail by means of specific embodiments with reference to the accompanying drawings.

In the description of the present application: unless otherwise indicated, the meaning of "a plurality" is two or more. The terms "first," "second," "third," and the like in this disclosure are intended to distinguish between the referenced objects without a special meaning in terms of technical connotation (e.g., should not be construed as emphasis on the degree of importance or order, etc.). The expressions "comprising", "including", "having", etc. also mean "not limited to" (certain units, components, materials, steps, etc.).

The terms such as "upper", "lower", "left", "right", "middle", etc. are generally used herein for convenience of visual understanding with reference to the drawings and are not to be construed as absolute limitations on the positional relationship of the actual product. Such changes in the relative positional relationship without departing from the technical idea of the present application are also considered as the scope of the present application.

Example 1

In order to solve the problems in the prior art, the application provides an external kiln channel supporting type double-chamber lime kiln (hereinafter referred to as external kiln channel supporting type double-chamber lime kiln) for mixing and blowing. The external passage supporting type double-chamber lime kiln is an active lime production device capable of realizing the production function conversion of a single-chamber shaft kiln and a double-chamber shaft kiln.

The application provides an external channel supporting type double-chamber lime kiln, which is a novel double-chamber vertical kiln, and adopts the measures of an external circulating flue, an external flue type inclined supporting structure, a detachable spray gun device, an expanded furnace body structure, a flue control valve, a full-automatic external flue kiln ash removal pneumatic conveying device, a multi-point rotary weighing ash discharging system, kiln top waste gas waste heat drying screening, suspension calcination powder and the like, thereby not only realizing the purpose of independently using massive solid fuel for mixed material production, but also realizing the purposes of double-chamber heat storage and powder fuel injection (such as coal, biomass and the like) and gas fuel (such as industrial tail gas, biomass gas, natural gas and the like) for producing high-activity lime, and also realizing the purpose of waste gas waste heat suspension calcination of powder lime.

In addition, the external passage supporting type double-chamber lime kiln provided by the application also solves the key problems of structural defects, production defects, potential safety hazards and the like caused by the arrangement of bracket supporting and hanging cylinder structures in the kiln of the traditional double-chamber kiln.

In order to highlight the differences between the solution proposed by the present application and the conventional double-bore shaft kiln, the structural principle of the conventional double-bore shaft kiln will be described with reference to fig. 1 and 2.

Fig. 1 is a schematic structural diagram of a corbel-type double-chamber kiln, as can be seen from the figure, two kiln chambers are arranged in parallel in the figure, wherein: a1 is a bracket type supporting part in the kiln, a plurality of supporting structures built by refractory bricks are annularly and uniformly distributed in the kiln body, and kiln body structures of the whole kiln body preheating zone and the calcining zone are supported. and a2 is an annular smoke channel in the kiln and is used for communicating smoke connecting two kiln bores. a3 is a fire poking hole, and a plurality of fire poking holes are arranged at the upper part of the annular channel and are used for manually cleaning ash. a4 is a fixed ash discharging device, and ash is discharged in a parallel micro-movement mode. The part a5 is provided with a plurality of manual tumor-clearing manhole devices, and the outside of the kiln body is provided with a plurality of fixed ash discharging devices used for manually clearing when the large-block material nodulation cannot be removed due to small movement quantity of the fixed ash discharging devices at the part a 4. and a6 is an air cannon, and high-pressure air is required to be adopted to clean the dust deposited in a2 part in production.

Fig. 2 is a schematic structural view of a suspension cylinder type double-chamber kiln, as can be seen from the figure, two kiln chambers are arranged in parallel in the figure, wherein: b1 is a hanging cylinder part in the kiln, a kiln shell of the calcining zone in the kiln body is connected with the upper part of the annular channel in an annular hanging way, the kiln body structure of the whole kiln preheating zone and the calcining zone is hung in the air, and a special high-pressure fan is needed to ventilate and cool in the hanging cylinder. b2 is an annular smoke channel in the kiln, which is used for communicating smoke of two kiln bores. b3 is a fire hole, and a plurality of fire holes are arranged at the upper part of the annular channel for manually cleaning ash. b4 is a fixed ash discharging device, and ash is discharged in a parallel micro-movement mode. The part b5 is provided with a plurality of manual tumor-clearing manhole devices, and the outside of the kiln body is provided with a plurality of fixed ash discharging devices used for manually clearing when the bulk material nodulation cannot be removed due to the small movement quantity of the fixed ash discharging devices at the part b 4. b6 is an air cannon, and high-pressure air is needed to clean the dust deposited in b2 during production.

It can be seen from fig. 1 and 2 that the conventional double-chamber kiln structure is arranged in the kiln, whether the bracket structure or the suspension cylinder structure is arranged in the kiln, and the smoke annular channel is required to be cleaned by an air gun and periodically shut down for cleaning dust, the cleaned deposited dust falls into the kiln, and cannot be cleaned out of the kiln, so that the key problems of easy sintering, caking and the like caused by long-time deposition of the deposited dust in a high-temperature zone of the smoke circulating channel are not fundamentally solved. Furthermore, the ash discharging device is fixed, and the ash discharging device cannot rotate, so that massive materials cannot be discharged, and the material level in the kiln cannot be adjusted.

The structural principle of the external kiln channel supporting type double-chamber lime kiln provided by the application is described in detail below with reference to the accompanying drawings.

The application provides an external-kiln channel supporting type double-hearth lime kiln, which comprises two adjacent vertical kilns, wherein each vertical kiln comprises a kiln body, the kiln body is provided with a kiln top, a kiln bottom, kiln walls and kiln hearths, and a preheating zone, a calcining zone and a cooling zone are formed in each kiln hearth from top to bottom; the preheating zone and the calcining zone are both straight cylinder structures, the cooling zone is of an extended right circular cone structure, and the inner diameter of the kiln chamber is gradually enlarged from the bottom of the calcining zone to the bottom of the cooling zone. The kiln top combustion air conversion valve 1, the kiln top waste gas conversion valve 2, the two-stage sealing feeding device 3, the lifting rotary composite distributing device 4 and the kiln top external air inlet pipeline valve are arranged on the two kiln tops. A plurality of detachable spray guns 5 which are annularly arranged are arranged on the two kiln walls, and the outlets of the detachable spray guns 5 are arranged at the joint part of the bottom of the preheating zone and the upper part of the calcining zone. An external annular smoke circulation channel 6 is arranged outside the kiln body at the lower part of each calcining zone, and a flue control valve 8 is arranged at the tangential position between the external annular smoke circulation channels 6 on the two kiln bodies. A combustion-supporting hood 14 is arranged in each kiln chamber. Each kiln bottom is provided with a mineral discharging system and an ash discharging system, the mineral discharging system is used for conveying cooled calcium oxide to the ash discharging system, and the ash discharging system is used for discharging the calcium oxide out of the kiln.

The kiln top waste gas conversion valve 2 is connected with an external dust remover pipeline, and the two-stage sealing feeding device 3 and the lifting rotary composite distributing device 4 are used for conveying mixed stone and blocky coal into the kiln; the lifting rotary composite distributor 4 is provided with a manipulator type distributor 4-1 which is used for arranging large-particle stones in the center of the kiln and arranging small-particle stones at the periphery of the kiln wall; the lifting rotary composite distributing device 4 is also provided with a chute type material scattering channel 4-2.

Each kiln top is provided with a buffer bin 21, the buffer bins 21 are used for receiving stones conveyed by an external elevator, and kiln top fixed screening devices 22 and preheating and drying devices are arranged in the buffer bins 21 of the kiln top; the kiln top fixed screening device 22 is used for carrying out secondary screening on stones, the lower part of the kiln top fixed screening device 22 is connected with the undersize collection bin 23, the outlet of the undersize collection bin 23 is connected with the composite crushing device 26, the outlet of the composite crushing device 26 is connected with the single-cylinder spinning suspension preheater 27, the outlet of the single-cylinder spinning suspension preheater 27 is connected with the powder suspension calcination channel 25, and a plurality of baffle plates 25-1 are arranged in the powder suspension calcination channel 25.

The powder suspension calcination channel 25 is connected with a double-cylinder spinning suspension preheater 31, the outlet of the double-cylinder spinning suspension preheater 31 is connected with a constant-temperature calcination reaction kettle 32, the constant-temperature calcination reaction kettle 32 is connected with an exhaust gas outlet pipe of the powder release bin 28, and the constant-temperature calcination reaction kettle 32 carries out constant-temperature flash calcination on lime powder through high-temperature exhaust gas fed into the constant-temperature calcination reaction kettle 32 to decompose the lime powder into active lime. Wherein: an electromagnetic induction heating temperature-regulating device 33 is arranged on the exhaust gas outlet pipe of the powder discharging bin 28, the electromagnetic induction heating temperature-regulating device 33 is used for heating the exhaust gas discharged from the powder discharging bin 28 to a set temperature, and the exhaust gas heated to the set temperature is sent into the constant temperature calcination reaction kettle 32.

The external annular flue gas circulation channel 6 is fixed on the kiln wall through an external flue type inclined support channel 7 arranged below the external annular flue gas circulation channel 6, and a plurality of external flue type inclined support channels 7 are communicated with the external annular flue gas circulation channel 6; the external annular flue gas circulation channel 6 is communicated with the powder suspension calcination channel 25 through a flue gas circulation channel pressure-regulating release valve 24.

A circulating flue ash collection bin 9 is arranged between the two external flue type inclined support channels 7, the lower outlet of the circulating flue ash collection bin 9 is communicated with an annular ash removal pneumatic conveying pipeline 11, and a pulse ash discharge valve 10 is arranged on the pipeline for connecting the circulating flue ash collection bin 9 and the annular ash removal pneumatic conveying pipeline 11.

The annular ash removal pneumatic conveying pipeline 11 is connected with an ash removal pneumatic conveying external pipeline 12, and the ash removal pneumatic conveying external pipeline 12 is connected with a powder release bin 28; the powder release bin 28 is provided with a cyclone dust removal and filtration device which is used for separating dust and smoke; the separated dust descends to the lower ash hopper, and the separated flue gas ascends to enter the powder suspension calcination channel 25 through the pressure release adjusting device 29; the annular ash removal pneumatic conveying pipeline 11 is connected with an ash removal pneumatic conveying internal connecting pipeline 13, and the ash removal pneumatic conveying internal connecting pipeline 13 is used for discharging dust materials to the outside of the kiln.

The ore discharging system of the present application includes a plurality of peripheral discharging devices 15 equally arranged in the circumferential direction of the kiln wall, and a center discharging device 16 arranged at the center of the plurality of peripheral discharging devices 15.

The ash discharging system comprises a directional rotation ash discharging device 17 and a metering device 18, wherein a discharging pipe of a peripheral discharging device 15 and a discharging pipe of a central discharging device 16 are communicated with the directional rotation ash discharging device 17, and the directional rotation ash discharging device 17 is used for discharging calcium oxide into the metering devices 18; the metering device 18 is connected with a furnace bottom ash discharging bin, the furnace bottom ash discharging bin is connected with a multi-stage sealing discharger 19, and the multi-stage sealing discharger 19 is used for discharging the calcium oxide discharged in a metering mode out of the kiln body.

1. The outer shell of the annular flue gas channel is connected with the furnace body shell by adopting steel, refractory materials are built in the outer shell, and the annular flue gas channels between the two kiln bores are connected in an intercommunicating manner.

2. The annular flue gas channel on the kiln body is communicated with the flue gas in the kiln, a plurality of independent inclined flue type supporting structures are adopted for carrying out structural support, the outer shell of each inclined flue type supporting structure is connected with the annular flue gas channel and the kiln shell through a steel structure, refractory materials are built in the annular flue gas channel, and the inside of each inclined flue type supporting structure is hollow.

3. The preheating zone and the calcining zone on the kiln body adopt straight cylinder structures, and refractory materials are built in the kiln body to meet the technological requirements of mixing type lime production; the cooling belt on the kiln body adopts an extended right circular cone steel structure, and refractory materials are built in the cooling belt to meet the technological requirements of the double-hearth kiln body during production.

4. A heat-resistant control valve is arranged at the tangential position between the smoke annular channels on the two kiln bodies, and when the double-hearth kiln body is adopted for production, the valve is opened to realize the intercommunication of the smoke of the two kiln vaults and the adjustment of the smoke flow; when the mixed material type production is adopted, the valve is closed to block the intercommunication of the smoke of the two kiln bores, so that the single-bore mixed material type production is realized.

5. And a circulating flue ash collection bin is arranged between every two inclined flue type supporting structures at the lower part of the external annular flue gas circulating channel, refractory materials are built or poured in the circulating flue ash collection bin, and a valve or a feeding device is arranged at an outlet at the lower part of the circulating flue ash collection bin and is connected with an annular pneumatic conveying pipeline.

6. The kiln body is provided with an ash discharging system which comprises a unidirectional rotation ash discharging device and a metering device, wherein the ash discharging system is a multi-point rotation weighing ash discharging system, and materials can be conveyed into the weighing device through a rotating mechanism so as to accurately control ash discharging amount and adjust furnace conditions.

7. A portable detachable spray gun is arranged in a kiln preheating zone, and a spray gun outlet is arranged at the joint part of the bottom of the preheating zone and the upper part of a calcining zone, so that the purpose of injecting solid powdery fuel and gas fuel during the production of the double-hearth kiln is realized; the spray gun structure is detachable, and the spray gun can be conveniently detached when the mixed material type production is adopted.

8. A kiln top fixed screening device 22 and a preheating and drying device are arranged in a buffer bin 21 at the kiln top, stone materials are screened for the second time, and screened powder directly enters a composite crushing device 26 for fine crushing; a single-cylinder spinning suspension preheater 27 is arranged at the lower part of the composite crushing device 26 to carry out primary preheating decomposition, so that the lime powder decomposition temperature reaches more than 300 ℃; a double-drum spinning suspension preheater 31 is arranged at the lower part of the single-drum spinning suspension preheater 27 to carry out secondary preheating decomposition, so that the lime powder decomposition temperature reaches more than 800 ℃; a constant temperature calcination reaction kettle 32 is arranged at the lower part of the double-drum spinning suspension preheater 31, and the constant temperature flash calcination is carried out on lime powder by using waste gas at the temperature of about 600-700 ℃ from a waste gas circulation channel of the lime kiln body, so that the lime powder is decomposed into active lime within 1 second.

9. An electromagnetic induction heating temperature regulating device 33 is arranged on an exhaust gas outlet pipeline of the powder releasing bin 28, so that the exhaust gas at the temperature of about 600-700 ℃ released by the powder releasing bin 28 is heated to about 1100 ℃ and is conveyed into the constant-temperature calcination reaction kettle 32 to increase the temperature, and the purpose of constant-temperature flash calcination is achieved; the electromagnetic induction heating temperature adjusting device 33 has the function of adjusting the temperature, so that the temperature of the constant temperature calcination reaction kettle 32 can be adjusted and can be kept constant within a temperature range.

The advantages of the external passage supporting type double-chamber lime kiln provided by the application are described in detail below in terms of structural function.

1. The kiln outer channel supporting type double-chamber lime kiln provided by the application is provided with the kiln outer waste heat smoke circulation channel, so that the kiln body structure is more reasonable and safer; the kiln outer flue is supported in an inclined way, so that combustion and flue gas in the kiln are circularly and uniformly distributed, and dead angles are avoided; the kiln inner cooling belt adopts an expansion type furnace body structure, the diameter of the kiln body is gradually enlarged from the bottom of the kiln body calcining belt, so that the trend of waste heat flue gas flow of the calcining belt and the cooling belt is more reasonable, the material cooling time of the cooling belt is more sufficient, and the lime activity is higher.

2. The external-kiln channel supporting type double-chamber lime kiln provided by the application is provided with a plurality of deposited ash removing devices at the lower part of a flue gas circulation channel outside the kiln body, and the deposited ash conveying and transferring are realized by adopting a pneumatic conveying mode, so that the defects that the traditional double-chamber kiln needs air cannon high-pressure ash removal and manual ash removal by stopping periodically are overcome.

3. The external-kiln channel supporting type double-chamber lime kiln provided by the application adopts a multi-point rotary weighing type ash discharging mode, so that multi-point unloading and material weighing are realized, and adjustment and weighing of different ash discharging amounts in different production processes are realized.

4. The kiln outer channel supporting type double-chamber lime kiln provided by the application is provided with the device for realizing kiln top screening and flue gas pressure equalizing and drying, so that stones are automatically screened on the kiln top for secondary screening, and are dried and preheated with part of waste gas of a flue gas circulation channel, thereby not only achieving the purpose of flue gas pressure equalizing, but also enabling the screening effect to be more obvious.

5. The external channel supporting type double-chamber lime kiln provided by the application also has the function of small-particle stone suspension calcination, and a stone powder fine powder crushing device, namely a composite crushing device 26 is arranged on the top of the kiln, so that stone powder screened on the top of the kiln can be crushed to be less than 1mm, and suspension heat exchange calcination is carried out on the stone powder and flue gas waste gas in a constant temperature calcination reaction kettle 32, so that the powder is directly converted into lime powder (calcium oxide powder), and the purposes of energy conservation and waste heat utilization are achieved.

6. The annular flue gas circulation channel 6 outside the kiln body of the kiln outer channel supporting type double-chamber lime kiln provided by the application is provided with a plurality of deposited ash removing devices at the lower part, and waste heat and waste gas released after the deposited ash is pneumatically conveyed are heated again in an electromagnetic induction mode, so that the temperature of the waste gas reaches the decomposition temperature of lime powder during suspension combustion, and the waste heat of the waste gas is recycled for lime production, thereby realizing energy conservation and emission reduction.

7. The flue control valve is arranged in the flue between the two kiln bores of the external-kiln channel supporting type double-bore lime kiln provided by the application, so that the opening and closing of waste heat flue gas between the two kiln bores are realized, the independent production function of a single-bore kiln in mixed material production and the heat storage function of the intercommunication of two kiln body flue gas in double-bore heat storage production are achieved, and the convenient detachable spray gun is adopted, so that the process adjustment in different fuel structures is convenient.

Example two

The external channel supporting type double-chamber lime kiln provided by the application can realize the function conversion and exchange between a mixed material type single-chamber countercurrent heat exchange production process and a double-chamber parallel-flow calcining countercurrent heat storage production process. The implementation of the batch type production process is described below.

The process principle of the mixed material type production process is as follows:

firstly, closing a block valve (namely a flue control valve 8) arranged at the middle communicating part of the flue gas channels of two kiln bores, so that each kiln bore forms an independent flue gas circulation system, and each independent kiln bore can independently operate. Then, an external induced air pipeline (connected with a kiln top flue gas dust remover) at the kiln top is opened, so that the preheating zone inside each independent kiln chamber is negative pressure.

Stone and solid block fuel (anthracite or coke with granularity of 20-40 mm) are mixed and then enter a preheating zone at the upper part in the kiln, and when the stone in the preheating zone slowly descends to the upper part of a calcining zone in the kiln, the stone reaches an initial decomposition temperature above 890 ℃. When the stone material after initial decomposition slowly descends to the middle part of the calcining zone in the furnace, the stone material reaches a temperature above 1100 ℃ which can be completely decomposed, carbon dioxide in the limestone in the area can be fully decomposed and released, and the limestone is decomposed into calcium oxide (lime). The decomposed calcium oxide slowly descends to the lower part of the calcining zone in the furnace and exchanges heat with the high-pressure cooling air input by the air inlet at the bottom of the kiln. The high pressure of the cooling air makes the heat exchanged hot air at 400-600 deg.c raise to the optimal lime stone decomposing temperature in 1000-1200 deg.c to utilize heat energy. The calcium oxide (lime) of the cooling belt slowly descends to the lower part of the cooling belt in the cooling process, and enters the ore discharging system after being cooled to the temperature of 50-150 ℃.

The ore discharging system is arranged at the bottom of a furnace (namely, the bottom of the kiln), and comprises a plurality of peripheral discharging bins and a furnace center discharging bin which are equally divided according to the periphery of the kiln wall, calcium oxide (lime) discharged by cooling is lowered onto a unidirectional rotation ash discharging device through peripheral and center discharging pipes, then the calcium oxide is discharged into a plurality of metering devices through rotation, the metered calcium oxide is discharged into the furnace bottom material ash discharging bin through a discharging controller, and materials are discharged out of the furnace through a two-stage sealing discharger.

The external channel supporting type double-chamber lime kiln provided by the application has the following specific operation flow for realizing the mixed material type production process:

(1) closing the flue control valve 8 to enable each kiln chamber to form an independent smoke circulation system capable of operating normally;

(2) closing a kiln top combustion air conversion valve 1, opening a kiln top waste gas conversion valve 2, connecting with an external dust remover pipeline, and forming negative pressure in a kiln chamber under the action of a dust remover induced draft fan;

(3) after stone and massive coal are mixed outside, the stone and massive coal are conveyed into the kiln through the two-stage sealing feeding device 3 and the internal channel of the lifting rotary composite distributing device 4, and uniform distribution in the kiln is realized through the lifting device and the rotating device of the lifting rotary composite distributing device 4; wherein: the lifting rotary composite distributor 4 is provided with a manipulator type distributor 4-1, so that large-particle stones can be arranged at the center of the kiln, and small-particle stones are arranged at the periphery of the kiln wall;

(4) the material in the kiln slowly descends under the action of the ash discharging device at the bottom of the kiln, when the material descends to the position of the calcining zone, combustion air from the combustion-supporting air cap 14 combusts with fuel in stones, and an optimal limestone decomposition temperature space body in the range of 1000-1200 ℃ is formed in the whole calcining zone, so that CO in the limestone is obtained ₂ Can be rapidly decomposed to form calcium oxide (lime);

(5) when the calcium oxide continuously and slowly descends to the lower part of the calcining zone, heat exchange and cooling are carried out on the calcium oxide and the combustion air from the bottom of the kiln, and the combustion air after heat exchange continuously ascends to the calcining zone to participate in combustion; after the burnt waste gas passes through a preheating zone and fully exchanges heat with stone, the temperature of the waste gas is reduced to 120-200 ℃, and the waste gas is discharged out of the kiln through a kiln top waste gas conversion valve 2 and enters a dust removal system;

(6) when the calcium oxide descends to the lower space of the kiln bottom combustion-supporting hood 14, the whole cooling process is completed, so that the calcium oxide is cooled to the range of 50-150 ℃ and then enters the peripheral discharging device 15 and the central discharging device 16; the material is discharged into the metering device 18 at fixed points by the rotation of the directional rotation ash discharging device 17; the material falling speed in the whole kiln depends on the rotation speed of the directional rotation ash discharging device 17 and the ash discharging amount set by the metering device 18; the weighed calcium oxide is discharged out of the kiln by a multi-stage sealing discharger 19.

Compared with the traditional mixing production mode, the mixing production mode carried out by the external kiln channel supporting type double-chamber lime kiln has the following advantages:

1. the production mode that the traditional single-chamber mixed lime shaft kiln can only use solid fuels such as single blocky anthracite or coke is changed, and the low-cost pulverized bituminous coal and biomass powder fuel can be used for blowing, so that the benefit is improved.

2. Can realize the injection of industrial tail gas (such as blast furnace gas, converter gas, coke oven gas, producer gas and the like) and biomass gas and other gas fuels in the single-hearth shaft kiln, and realize the environmental treatment and carbon reduction benefits.

3. Because the spray gun is arranged in the kiln and the spray gun adopts the cross-section arrangement, the combustion effect is more sufficient and uniform, the raw overburning rate of lime products is reduced by at least more than 10%, and the purposes of improving quality and enhancing efficiency of the products are realized.

4. The external passage supporting type double-chamber lime kiln provided by the application is a double-chamber vertical kiln, can be improved on the basis of the structure of the traditional single-chamber mixed lime vertical kiln, and is provided that two vertical kilns with the same kiln volume are required and the distance between the two vertical kilns is proper.

5. The main technical structural characteristics of the traditional coal-fired lime shaft kiln and the gas-fired lime shaft kiln are not changed, so that most lime shaft kiln can be transformed into the kiln outer channel supporting type double-chamber lime kiln provided by the application, and the industrial popularization is facilitated.

6. The traditional single-chamber mixed lime shaft kiln is transformed into a double-chamber lime shaft kiln, which meets the requirements of environmental protection, energy conservation and the like, and avoids the destiny of the traditional single-chamber mixed lime shaft kiln.

Example III

The external channel supporting type double-chamber lime kiln provided by the application can realize the function conversion and exchange between a mixed material type single-chamber countercurrent heat exchange production process and a double-chamber parallel-flow calcining countercurrent heat storage production process. The following describes the implementation of the pulverized coal injection and gas fuel production process.

A plurality of detachable fuel spray guns which are annularly arranged are respectively arranged in the two kiln chamber preheating zones and are buried in stones in the preheating zones. The two kiln bores are produced alternately, and when one kiln bore is calcined, the other kiln bore is in a heat storage state. The first and second kilns are reversed for calcination every 15 minutes or other set time.

In the production, firstly, a block valve arranged at the middle intercommunication part of the smoke channels of the two kiln bores is opened, so that the smoke of the two kiln bores can be communicated. Then, the external air inlet pipeline valve at the kiln top is opened, and high-pressure combustion air is blown into the kiln chamber preheating zone through the combustion-supporting fan, so that the calcining kiln chamber is always in a positive pressure state during calcining. In the process of flowing downwards from the preheating zone, the combustion air is preheated by heat exchange with the hot limestone in the preheating zone. When the preheated combustion air reaches the calcining zone, the preheated combustion air is mixed with the coal dust or gas and other fuels conveyed by the spray gun and then burnt. The high-temperature gas after combustion and the limestone after heat absorption flow downwards together, penetrate through the whole calcining zone, complete the decomposition of the limestone, decompose the limestone into calcium oxide (lime) and complete the co-current calcining production process.

When the high-temperature flue gas of the calcining zone reaches the junction of the bottom of the calcining zone and the upper part of the cooling zone, the high-temperature flue gas is mixed with cooling air from the kiln bottom to form new air flow, the flue gas flows to a plurality of inner channels which are obliquely supported by the flue channels outside the kiln and are converged in a flue gas circulation channel due to the positive pressure intensity in the kiln, and the converged waste heat flue gas flows to another kiln chamber which is in heat accumulation, and the high-temperature flue gas rises from bottom to top due to the fact that the pressure intensity in the heat accumulation kiln chamber is lower than that of the calcining chamber, penetrates through the whole calcining zone to reach the preheating zone, contacts with limestone in the preheating zone and exchanges heat, so that the countercurrent heat accumulation process is completed.

When the calcination is carried out in the calcination chamber, the fuel spray gun of the heat storage chamber is closed, the kiln top combustion air valve is also closed, waste gas rises and the newly input stone at the upper part of the preheating belt is released by waste heat, so that the waste gas is discharged from a kiln top waste gas pipeline after the temperature of the waste gas is reduced to the range of 60-150 ℃ and enters the kiln outer dust removal system.

The calcium oxide (lime) in the calcining chamber and the heat accumulating chamber cooling belt slowly descends to the lower part of the cooling belt in the cooling process, and enters the ore discharging system after being cooled to the temperature of 50-150 ℃.

The system of ore discharging part arranged at the bottom of furnace is provided with a plurality of peripheral discharging bins and furnace center discharging bins which are equally divided according to the periphery of the kiln wall, the cooled and discharged calcium oxide (lime) is lowered onto the unidirectional rotation ash discharging device through the peripheral and center discharging tubes, the calcium oxide is discharged into a plurality of metering devices through rotation, the metered calcium oxide is discharged into the furnace bottom material ash discharging bin through the discharging controller, and the materials are discharged out of the furnace through the two-stage sealing discharger.

The external passage supporting type double-chamber lime kiln provided by the application has the following specific operation flow (for convenience of distinguishing, two kiln chambers are denoted as a chamber and a chamber B):

(1) Opening a flue control valve 8 to enable the waste gas of the chamber A and the chamber B to circulate mutually;

(2) opening a combustion air conversion valve 1 on the top of the kiln chamber A, and blowing high-pressure combustion air into a kiln chamber preheating zone through a combustion fan to ensure that the calcining kiln chamber is always in a positive pressure state during calcining;

(3) the detachable spray gun 5 is started to convey powder coal fuel or gas fuel into the chamber A, and the powder coal fuel or gas fuel is mixed with high-pressure combustion air from top to bottom to form a flaming combustion flame; in the heat exchange process, flame and stone move in the same direction to finish the parallel flow calcination process; in the process, the limestone finishes decomposing carbon dioxide to form calcium oxide (lime);

(4) the decomposed calcium oxide slowly descends to the position of an external annular smoke circulation channel 6, and is converged with countercurrent cooling air from the bottom of the kiln to the top of a combustion-supporting air cap 14 to form positive pressure airflow; the converged air flows flow into the external annular smoke circulation channel 6 through the internal channels of the external flue type inclined support channels 7, and the external flue type inclined support channels 7 are arranged in a plurality and are all communicated with the inside of the annular smoke circulation channel 6;

(5) In the same time period for completing the whole operation process of the chamber A, the chamber B closes the combustion air conversion valve 1 on the kiln top, stops the fuel supply of the detachable spray gun 5 thereon, opens the kiln top waste gas conversion valve 2 to be connected with an external dust remover pipeline, and enables the whole chamber B to form a negative pressure heat storage state under the action of a dust remover induced draft fan; because of the pressure difference between the A chamber and the B chamber, the high-temperature waste heat flue gas in the annular flue gas circulation channel 6 of the A chamber flows into the B chamber quickly, and is converged with the high-pressure combustion air from the combustion air cap 14 of the B chamber to form new positive pressure air flow, and the high-temperature waste gas from the A chamber and stone of the B chamber penetrate through the whole calcining zone and the preheating zone from bottom to top to perform full heat exchange to finish countercurrent heat accumulation; the flue gas after heat accumulation is discharged out of the kiln through a kiln top waste gas conversion valve 2 and enters a dust remover;

(6) and the chamber A and the chamber B are subjected to reversing for calcining every 15 minutes or other set time, and the operation flow is repeated.

In the operation flow, the feeding of the chamber A and the chamber B is completed by the two-stage sealing feeding device 3 and the lifting and rotating composite distributing device 4; the furnace bottom discharging is completed by a peripheral discharging device 15, a central discharging device 16, a directional rotating ash discharging device 17 and a metering device 18; the weighed calcium oxide is discharged out of the kiln by a multi-stage sealing discharger 19.

In the process of finishing heat accumulation and calcination by the mutual conversion of the bore A and the bore B, the dust in the external annular flue gas circulation channel 6 falls into the circulating flue dust collection bin 9, the dust is conveyed to the annular ash removal pneumatic conveying pipeline 11 for dilute-phase pneumatic mixing by utilizing the naturally-formed high-pressure airflow pressure in the kiln, a pneumatic conveying air source is provided by an externally independently arranged fan, and the pressure of the pneumatic conveying air is smaller than that in the kiln. The annular ash removal pneumatic conveying pipeline 11 is provided with two external interfaces, wherein the ash removal pneumatic conveying external pipeline 12 is responsible for conveying dust materials into a powder release bin 28, a cyclone dust removal filter device is arranged in the powder release bin 28 to separate dust from smoke, the separated dust descends into a lower ash accumulation hopper, and the separated smoke ascends and is connected with a pipeline through a pressure release adjusting device 29 to enter a powder suspension calcination channel 25 to participate in suspension calcination of powder; the ash removal pneumatic conveying internal connecting pipeline 13 can directly convey dust materials into a lime bin at the lower part of the kiln body and discharge the dust materials out of the kiln together with finished lime.

Stone conveyed by an external elevator enters a buffer bin 21 arranged on the kiln top, is screened by a kiln top fixed screening device 22, and qualified stone on the screen is conveyed into the kiln by an internal channel of a two-stage sealing feeding device 3 and a lifting rotary composite distributing device 4; the chute type material scattering channel 4-2 is adopted for material distribution so as to meet the stone material distribution process requirement during fuel injection. The undersize materials enter the undersize material collection bin 23, fall into the ash removal pneumatic conveying external pipeline 12 from the powder suspension calcination channel 25 and are conveyed to the powder release bin 28 together.

The external annular flue gas circulation channels 6 of the A bore and the B bore are provided with flue gas circulation channel pressure regulating release valves 24 in front of the flue control valve 8, partial waste gas can be released to carry out pressure regulation when the internal flue gas of the external annular flue gas circulation channels 6 of the A bore and the B bore needs to be regulated, the released high-temperature waste gas enters the powder suspension calcination channel 25, and the flue gas rises to the kiln top fixed screening device 22 and the buffer bin 21 due to the action of the waste gas pressure to carry out heat exchange with stone, so that the purposes of drying the stone and heat exchange are achieved. The undersize powder continues to undergo suspension countercurrent heat exchange with the exhaust gas in the powder suspension calcination channel 25. The powder suspension calcination channel 25 is provided with a plurality of baffle plates 25-1 to prolong the heat exchange time of the flue gas and the stone powder, thereby achieving the purpose of fully utilizing the heat energy of the waste gas.

The powder suspension calcination channel 25 has multiple functions, and can realize the dispersion and suspension of raw stone powder in the air flow; the heat exchange between the gas phase and the solid phase is carried out in the whole closed ascending pipeline; the waste gas is circulated into a waste gas main pipeline at the kiln top, and then concentrated and discharged for dust removal treatment. The whole suspension combustion process is endothermic decomposition reaction, when the temperature of the waste gas is raised to 550 ℃, calcium carbonate begins to be decomposed into CaO by endothermic absorption, and CO is released ₂ And (3) gas. As the temperature increases, the decomposition rate increases, and a large amount of decomposition starts at 750 ℃. Decomposed CO ₂ The gas and part of the waste gas enter the kiln top waste gas conversion valve 2 through the waste gas branch pipe 30 or enter the waste gas main pipeline through the bypass pipeline.

The traditional double-hearth lime kiln can realize coal powder fuel and gas fuel injection, but is limited by the process and cannot be produced by using massive solid fuel, and currently, two main types of commonly used double-hearth shaft kilns are: bracket-type structures and suspension cylinder-type structures, as shown in fig. 1 and 2. Compared with the traditional double-hearth shaft kiln, the external-kiln channel supporting type double-hearth lime kiln provided by the application has at least the following advantages:

1. the kiln body calcining zone of the traditional double-hearth shaft kiln is changed to adopt the structural mode of supporting and hanging in the kiln, so that the production process is simpler and more practical, and the key problem that serious production accidents are possibly caused by collapse of the supporting and hanging in the kiln is solved.

2. The defect that the smoke circulation channel of the traditional double-hearth shaft kiln is arranged in the kiln is changed: construction and maintenance are difficult, dust is easy to accumulate in the channel, normal circulation of smoke in the channel is hindered, and the device is required to be stopped for periodic manual cleaning; the external flue gas circulation channel is arranged outside the kiln, and the pneumatic automatic ash removal and ash conveying are adopted, so that the external flue gas circulation channel is environment-friendly and safe, does not need manual cleaning, and is very convenient to construct, maintain and overhaul.

3. The application changes the inverted cone structure with big top and big bottom of the cooling belt of the traditional double-hearth shaft kiln body, adopts the right cone structure with big top and big bottom, and the cooling belt kiln shell is directly connected with the calcining belt kiln shell, so that the kiln body is more in line with the mechanical structure characteristics, the construction difficulty and the maintenance difficulty are reduced, and the air flow distribution in the kiln is more reasonable.

4. The application changes the disadvantages that the traditional double-chamber kiln fixed ash discharging device can not discharge large-block nodulation materials in the kiln due to the fact that ash can not be discharged in a rotating way and manual cleaning is needed.

5. The external passage supporting type double-chamber lime kiln provided by the application has the advantages of compact functional structure, reasonable layout and convenience in operation.

6. The kiln body structure is changed, so that the use level of the refractory materials in the kiln is reduced, the model selection of the refractory materials is wider, the construction is simpler, and the investment cost of the refractory materials is greatly reduced.

7. The external passage supporting type double-chamber lime kiln provided by the application can be obtained by reforming the traditional single-chamber shaft kiln, has low construction and use investment, and continues the characteristics of high return on investment and high cost performance of the traditional lime shaft kiln; compared with the investment of the traditional single-hearth mixed type coal-fired lime shaft kiln, the investment of the whole production system is not increased by removing an added power system, an in-kiln injection combustion system, a coal powder preparation system and the like which are required to be added; compared with the investment of the traditional double-chamber lime kiln, the investment of the same yield has a large reduction space.

Example IV

The external passage supporting type double-chamber lime kiln provided by the application can also realize suspended calcination of powder lime.

The mixed material type production process provided by the second embodiment or the coal dust injection and gas fuel production process provided by the third embodiment can synchronously realize the production of powder lime.

The general production flow for realizing suspended calcination of powder lime is that when stones are lifted to the kiln top, the stones firstly enter a kiln top fixed screening device 22 for screening, and the stones with the granularity of 0-20 mm after screening enter a composite crushing device 26 for crushing; then, part of high-temperature waste gas and smoke of the furnace body circulation channel is released through a powder suspension calcination channel 25 arranged between the two kiln bodies, and the waste gas and smoke are subjected to countercurrent suspension type waste heat exchange decomposition with fine powder stone with granularity of 0-3 mm after the kiln top is crushed in the descending process. The heat exchange decomposition process is realized from top to bottom by a single-cylinder spinning suspension preheater, a double-cylinder spinning suspension preheater and a constant-temperature calcination reaction kettle.

The following describes in detail the process flow of synchronously realizing suspended calcination of powder lime in the mixed material production process based on the mixed material production process provided in the second embodiment:

The lower part of the buffer bin 21 is provided with a composite crushing device 26 for crushing the screened stone dust and coal particle fuel to a particle size suitable for suspension calcination;

the crushed stone and fuel mixed powder sequentially enter a single-drum spinning suspension preheater 27 and a double-drum spinning suspension preheater 31 through a powder suspension calcination channel 25, and finally enter a constant-temperature calcination reaction kettle 32 for decomposition and calcination;

the waste heat of the waste gas of the powder suspension calcination channel 25 is adjusted by adjusting the flow and the pressure of the waste gas released from the inside of the external annular smoke circulation channel 6 through the smoke circulation channel pressure-adjusting release valves 24 respectively arranged on the two kiln chambers, the outlet of the smoke circulation channel pressure-adjusting release valves 24 is provided with a waste gas enclosing pipe 20, and the waste gas enclosing pipe 20 is provided with a plurality of smoke nozzles 34 which are uniformly distributed in an annular shape and communicated with the inside of the constant temperature calcination reaction kettle 32, so that the stone powder and the fuel powder are dispersed, suspended and combusted in the air flow, the constant temperature flash calcination of the lime powder is realized, and the lime powder is decomposed into active lime.

The whole suspension burnsThe burning process is endothermic decomposition reaction, when the temperature of the waste gas is raised to 550 ℃, calcium carbonate begins to decompose into CaO and release CO ₂ And (3) gas. As the temperature increases, the decomposition rate increases, and a large amount of decomposition starts at 750 ℃. When the powder enters the constant temperature calcination reaction kettle 32, the powder and the high-temperature waste gas with the temperature of more than 1000 ℃ from the electromagnetic induction heating temperature regulating device 33 are subjected to final high-temperature flash decomposition, so that carbon dioxide is thoroughly released, and limestone powder decomposition work is completed. The exhaust gas of the electromagnetic induction heating temperature regulating device 33 comes from the smoke after the powder is released from the powder releasing bin 28.

Decomposed CO ₂ The gas and part of the waste gas enter the kiln top waste gas conversion valve 2 through the waste gas branch pipe 30 or enter the waste gas main exhaust pipe through the bypass pipeline. In the process, the heat exchange between gas and solid phases is carried out in the single-cylinder spinning suspension preheater 27 and the double-cylinder spinning suspension preheater 31, so that the waste gas flows into a kiln top waste gas main pipeline to be concentrated and discharged for dust removal treatment.

When the mixed material type production process is adopted, the crushed fine powder stone and the coal fine powder fuel synchronously enter the powder suspension calcination channel 25, and as the ignition point of the coal fuel is lower than the temperature of the waste gas in the channel, the direct combustion can be realized to participate in stone decomposition and calcination. When the decomposition temperature is insufficient, the heat energy is supplemented by the electromagnetic induction heating temperature adjusting device 33.

Based on the production process of pulverized coal injection and gas fuel provided in the third embodiment, the process flow of lime for suspension calcination powder is synchronously realized under the production process of pulverized coal injection and gas fuel, which is the same as the process flow of lime for suspension calcination powder under the production process of mixed materials.

When the temperature of the exhaust gas and the smoke in the powder suspension calcination channel 25 can not reach the decomposition temperature of the fine powder stone during the production process of the pulverized coal injection and the gas fuel, the electromagnetic induction heating temperature regulating device 33 is arranged to supplement heat energy, so that the ideal decomposition and calcination temperature can be reached.

The kiln outer channel supporting type double-chamber lime kiln provided by the application has a suspension type combustion system, can perform constant-temperature flash calcination on fine powder stone (small particle powder) and decompose lime powder into active lime, thereby realizing the purpose of producing lime by small particle powder, reducing the production cost and simultaneously realizing energy conservation and environmental protection.

The external-kiln channel supporting type double-chamber lime kiln provided by the application adopts a waste gas waste heat gas suspension mode to calcine powder lime, can calcine limestone fine particles with the granularity below 10mm and other various types of raw materials, wherein the raw materials comprise crushed or ground materials, and powder in natural or tailings, such as limestone mud cakes and the like, and the system has wide adaptability; furthermore, the multistage suspension heat exchange system is formed by the single-cylinder spinning suspension preheater 27, the double-cylinder spinning suspension preheater 31 and the constant-temperature calcination reaction kettle 32, so that the convection conduction heat efficiency is high, the unit heat consumption of the system can be ensured to be low, and the energy is saved; in addition, the application skillfully utilizes the height of the lime kiln body structure and the technological structural characteristics of the two kilns after combination, screens and breaks the kiln top of the lime kiln, saves the structural and equipment cost of stone material feeding, a furnace body frame, a platform, a pipeline and the like, and effectively reduces the investment cost.

In conclusion, the kiln outer channel supporting type double-chamber lime kiln provided by the application adopts the coal-fired mixed-burning lime shaft kiln to reform into a lime production system for fuel injection, and the kiln body has the advantages of simple, compact and practical structure, high production efficiency, high yield and good economy; especially, the method has important significance in improving the overall lime production process level, reducing the production cost, improving the product quality, reducing pollution and reducing carbon, improving the ecological environment and the like.

Any combination of the technical features of the above embodiments may be performed (as long as there is no contradiction between the combination of the technical features), and for brevity of description, all of the possible combinations of the technical features of the above embodiments are not described; these examples, which are not explicitly written, should also be considered as being within the scope of the present description.

The application has been described above with particularity and detail in connection with general description and specific embodiments. It should be understood that numerous conventional modifications and further innovations may be made to these specific embodiments, based on the technical concepts of the present application; but these conventional modifications and further innovations may also fall within the scope of the claims of the present application as long as they do not depart from the technical spirit of the present application.

Claims

1. The external channel supporting type double-chamber lime kiln for mixing and blowing is characterized by comprising two adjacent vertical kilns, wherein each vertical kiln comprises a kiln body, the kiln body is provided with a kiln top, a kiln bottom, kiln walls and a kiln chamber, and a preheating zone, a calcining zone and a cooling zone are formed in each kiln chamber from top to bottom; the preheating zone and the calcining zone are both of straight-cylinder type structures, and the cooling zone is of an extended right-circular cone type structure;

kiln top combustion air conversion valves (1), kiln top waste gas conversion valves (2), two-stage sealing feeding devices (3) and lifting rotary composite distributing devices (4) are arranged on the two kiln tops;

a plurality of detachable spray guns (5) which are annularly arranged are arranged on the two kiln walls, and the outlets of the detachable spray guns (5) are arranged at the joint part of the bottom of the preheating zone and the upper part of the calcining zone;

an external annular smoke circulation channel (6) is arranged outside the kiln body at the lower part of each calcining zone, and a flue control valve (8) is arranged at a tangential position between the external annular smoke circulation channels (6) on the two kiln bodies;

a combustion-supporting blast cap (14) is arranged in each kiln chamber,

2. The dual-purpose kiln external channel supporting type double-chamber lime kiln for mixing and blowing according to claim 1, wherein the kiln top waste gas conversion valve (2) is connected with an external dust remover pipeline, and the two-stage sealing feeding device (3) and the lifting rotary composite distributing device (4) are used for conveying mixed stone and blocky coal into the kiln; the lifting rotary composite distributor (4) is provided with a manipulator type distributor (4-1) which is used for arranging large-particle stones in the center of the kiln and small-particle stones at the periphery of the kiln wall;

kiln top external air inlet pipeline valves are arranged on the two kiln tops;

the lifting rotary composite distributing device (4) is also provided with a chute type material scattering channel (4-2).

3. The dual-purpose kiln external channel supporting type double-chamber lime kiln for mixing and blowing according to claim 1, wherein each kiln top is provided with a buffer bin (21), the buffer bins (21) are used for receiving stones conveyed by an external elevator, and kiln top fixing screening devices (22) and preheating and drying devices are arranged in the buffer bins (21) at the kiln top; the kiln top fixed screening device (22) is used for carrying out secondary screening on stones, the lower part of the kiln top fixed screening device (22) is connected with an undersize collection bin (23), the outlet of the undersize collection bin (23) is connected with a composite crushing device (26), the outlet of the composite crushing device (26) is connected with a single-cylinder spinning suspension preheater (27), the outlet of the single-cylinder spinning suspension preheater (27) is connected with a powder suspension calcination channel (25), and a plurality of baffle plates (25-1) are arranged in the powder suspension calcination channel (25); the powder suspension calcination channel (25) is connected with the double-cylinder spinning suspension preheater (31), the outlet of the double-cylinder spinning suspension preheater (31) is connected with the constant-temperature calcination reaction kettle (32), the constant-temperature calcination reaction kettle (32) is connected with an exhaust gas outlet pipe of the powder release bin (28), and the constant-temperature calcination reaction kettle (32) carries out constant-temperature flash calcination on lime powder through high-temperature exhaust gas fed into the constant-temperature calcination reaction kettle to decompose the lime powder into active lime;

An electromagnetic induction heating temperature regulating device (33) is arranged on an exhaust gas outlet pipe of the powder release bin (28), the electromagnetic induction heating temperature regulating device (33) is used for heating exhaust gas discharged from the powder release bin (28) to a set temperature, and the exhaust gas heated to the set temperature is sent into a constant temperature calcination reaction kettle (32).

4. The dual-purpose kiln external channel supporting type double-chamber lime kiln for mixing and blowing according to claim 3, wherein the external annular flue gas circulation channel (6) is fixed on the kiln wall through an inclined flue type supporting structure arranged below the external annular flue gas circulation channel, the inclined flue type supporting structure is an external flue type inclined supporting channel (7), and a plurality of external flue type inclined supporting channels (7) are communicated with the external annular flue gas circulation channel (6);

the external annular smoke circulation channel (6) is communicated with the powder suspension calcination channel (25) through a smoke circulation channel pressure-regulating release valve (24);

a circulating flue ash collection bin (9) is arranged between the two external flue type inclined support channels (7), the lower outlet of the circulating flue ash collection bin (9) is communicated with an annular ash removal pneumatic conveying pipeline (11), and a pulse ash discharge valve (10) is arranged on the pipeline used for connecting the circulating flue ash collection bin (9) and the annular ash removal pneumatic conveying pipeline (11).

5. The dual-purpose kiln external channel supporting type double-chamber lime kiln for mixing and blowing according to claim 4, wherein the annular ash removing pneumatic conveying pipeline (11) is connected with an ash removing pneumatic conveying external pipeline (12), and the ash removing pneumatic conveying external pipeline (12) is connected with a powder releasing bin (28); a cyclone dust removing and filtering device is arranged in the powder releasing bin (28) and is used for separating dust and smoke; the separated dust descends to the lower ash hopper, and the separated flue gas ascends to enter a powder suspension calcination channel (25) through a pressure release adjusting device (29);

the annular ash removal pneumatic conveying pipeline (11) is connected with the ash removal pneumatic conveying internal connecting pipeline (13), and the ash removal pneumatic conveying internal connecting pipeline (13) is used for discharging dust materials to the outside of the kiln.

6. The dual-purpose kiln external channel supporting type double-chamber lime kiln for mixing and blowing according to claim 1, wherein the ore discharging system comprises a plurality of peripheral discharging devices (15) which are equally arranged according to the circumferential direction of the kiln wall, and a central discharging device (16) which is arranged at the center of the plurality of peripheral discharging devices (15);

the ash discharging system comprises a directional rotation ash discharging device (17) and a metering device (18), wherein a discharging pipe of the peripheral discharging device (15) and a discharging pipe of the central discharging device (16) are communicated with the directional rotation ash discharging device (17), and the directional rotation ash discharging device (17) is used for discharging calcium oxide into a plurality of metering devices (18); the metering device (18) is connected with a furnace bottom material ash discharging bin, the furnace bottom material ash discharging bin is connected with a multistage sealing discharger (19), and the multistage sealing discharger (19) is used for discharging the metering discharged calcium oxide out of the kiln body.

7. The dual-purpose kiln external channel supporting type double-chamber lime kiln for mixing and blowing according to claim 1, wherein the inner diameter of the kiln chamber is gradually enlarged from the bottom of the calcining zone to the bottom of the cooling zone;

each kiln bottom is provided with an air inlet, and a kiln bottom cooling air conversion valve is arranged on each air inlet;

a combustion-supporting air cap (14) is arranged in each kiln chamber, and the combustion-supporting air caps (14) are positioned at the bottom of the kiln and above the ore discharge system;

the structures of the two shaft kilns are bilaterally symmetrical.

8. A production method for producing lime by using the dual-purpose kiln external channel supporting type double-chamber lime kiln for mixing and blowing according to any one of claims 1-7, characterized in that the mixing production process and the pulverized coal and gas fuel injection production process are switched by switching the opening and closing state of a flue control valve (8) arranged between two external annular flue gas circulation channels (6).

9. The method for producing lime by using the external kiln channel supporting type double-chamber lime kiln for mixing and blowing according to claim 8, which is characterized by closing a flue control valve (8) to realize a mixing type production process and specifically comprises the following steps:

s1: closing a flue control valve (8) to enable each kiln chamber to form an independent flue gas circulation system, closing a kiln top combustion air conversion valve (1) of any shaft kiln, and opening a kiln top waste gas conversion valve (2) to form negative pressure in the kiln chamber;

S2: the mixture of stone and blocky coal is conveyed into the kiln by a two-stage sealing feeding device (3) and a lifting rotary composite distributing device (4);

s3: when the material in the kiln descends to the position of the calcining zone, combustion air from the combustion-supporting air cap (14) combusts with fuel in stone, and CO in the stone ₂ Decomposing to form calcium oxide;

s4: when the calcium oxide continuously descends to the lower part of the calcining zone, heat exchange and cooling are carried out on the calcium oxide and the combustion air from the bottom of the kiln, and the combustion air after heat exchange continuously ascends to the calcining zone to participate in combustion; after the burnt waste gas passes through the preheating zone to exchange heat with stone, the temperature of the waste gas is reduced, and the waste gas is discharged out of the kiln through a kiln top waste gas conversion valve (2);

s5: after the calcium oxide continuously descends to the lower space of the combustion-supporting air cap (14) at the bottom of the kiln, the whole cooling process is completed, and then the calcium oxide sequentially enters the ore discharging system and the ash discharging system and is discharged out of the kiln through the ash discharging system.

10. The method for producing lime by using the external-kiln channel supported double-chamber lime kiln for mixing and blowing according to claim 8, wherein two vertical kilns are respectively denoted as an A vertical kiln and a B vertical kiln, and the chamber of the A vertical kiln is denoted as an A chamber and the chamber of the B vertical kiln is denoted as a B chamber; the flue control valve (8) is opened to realize the production process of pulverized coal injection and gas fuel, and the method specifically comprises the following steps:

S1: opening a flue control valve (8) to enable waste gas of the chamber A and the chamber B to circulate mutually;

s3: powder coal fuel or gas fuel is conveyed into the chamber A through a detachable spray gun (5) so as to be mixed with high-pressure combustion air from top to bottom to form incandescent combustion flame, the combustion flame penetrates through the calcining zone to form a high-temperature area of the calcining zone, stone materials are subjected to heat exchange in the high-temperature area of the calcining zone, and the flame and the stone materials move in the same direction in the heat exchange process to finish the parallel-flow calcining process; during this process the stone breaks down to form calcium oxide;

s4: the calcium oxide slowly descends to the position of the external annular smoke circulation channel (6), is intersected with countercurrent cooling air from bottom to top generated by a combustion-supporting air cap (14) at the bottom of the kiln, forms positive pressure airflow, and the intersected airflow flows to the external annular smoke circulation channel (6);

s5: and in the same time period when the bore A completes the operation steps S1 to S4, the bore B carries out the following steps: closing a combustion air conversion valve at the kiln top; stopping the fuel supply to the removable lance (5) thereon; opening a kiln top waste gas conversion valve (2) to be connected with an external dust remover pipeline, and enabling the whole B chamber to form a negative pressure heat storage state under the action of the external dust remover; because of the pressure difference between the A chamber and the B chamber, high-temperature waste heat flue gas in an external annular flue gas circulation channel (6) of the A shaft kiln quickly flows into the B chamber and is converged with high-pressure combustion air of the B chamber to form new positive-pressure airflow, so that high-temperature waste gas of the A chamber and stone of the B chamber penetrate through the whole calcining zone and the preheating zone from bottom to top to fully exchange heat, and countercurrent heat storage is completed; the flue gas after heat accumulation is discharged out of the kiln through a kiln top waste gas conversion valve (2) and enters an external dust remover;

11. The method for producing lime by using the external kiln channel supported double-chamber lime kiln for mixing and blowing according to claim 8, wherein the suspension type powder lime calcining process can be realized under both the mixing production process and the pulverized coal and gas fuel injection production process;

the suspended calcination powder lime process comprises the following steps: a buffer bin (21) is arranged at each kiln top, a kiln top fixed screening device (22) and a preheating and drying device are arranged in each buffer bin (21), the kiln top fixed screening device (22) is connected with a composite crushing device (26), the outlet of the composite crushing device (26) is connected with a single-cylinder spinning suspension preheater (27), the outlet of the single-cylinder spinning suspension preheater (27) is connected with a powder suspension calcination channel (25), the powder suspension calcination channel (25) is connected with a double-cylinder spinning suspension preheater (31), the outlet of the double-cylinder spinning suspension preheater (31) is connected with a constant temperature calcination reaction kettle (32), the constant temperature calcination reaction kettle (32) is connected with an exhaust outlet pipe of a powder release bin (28), and an electromagnetic induction heating temperature regulating device (33) is arranged on the exhaust outlet pipe of the powder release bin (28);

Crushing the sieved stone dust and coal particle fuel to a target particle size for suspension calcination by the composite crushing device (26);

the crushed stone and fuel mixed powder sequentially enter a single-cylinder spinning suspension preheater (27) and a double-cylinder spinning suspension preheater (31) through a powder suspension calcination channel (25), finally enter a constant-temperature calcination reaction kettle (32), and are decomposed and calcined with waste gas from a powder release bin (28) to generate active lime.