CN111847907A

CN111847907A - Lime kiln and heat supply method thereof

Info

Publication number: CN111847907A
Application number: CN201910340082.7A
Authority: CN
Inventors: 周浩宇; 王赛辉; 刘前; 潘绍兵; 万忠炎; 曾文波; 李谦; 王业峰; 陈思墨
Original assignee: Zhongye Changtian International Engineering Co Ltd
Current assignee: Zhongye Changtian International Engineering Co Ltd
Priority date: 2019-04-25
Filing date: 2019-04-25
Publication date: 2020-10-30
Anticipated expiration: 2039-04-25
Also published as: UA128460C2; WO2020216289A1; BR112021013845A2; CN111847907B

Abstract

The application discloses a lime kiln and a heat supply method thereof, wherein a heat supply device comprises a fuel supply device and a spray gun group, and a coal gas supply device and a coal powder supply device share the spray gun group; a coal gas branch pipe regulating valve is arranged on each coal gas branch pipe, and a coal powder branch pipe regulating valve is arranged on each coal powder branch pipe; a flow detector is arranged on the spray gun; a first heat value detector and a first pressure detector are respectively arranged on the coal gas ring pipe, a second heat value detector is arranged on the coal powder ring pipe, and a second pressure detector is arranged inside the kiln chamber; the section of the kiln chamber is sequentially divided into a plurality of annular heat supply areas along the radial direction, the spray gun group comprises a plurality of spray gun matrixes, each spray gun matrix is correspondingly arranged in one annular heat supply area, each spray gun matrix comprises a plurality of spray guns uniformly distributed along the circumference, and the spray gun group is provided with N spray guns in total. This application can be according to the pressure state of gas ring pipe, adjusts the heat supply mode, realizes the switching of spray gun fuel to realize accurate heat supply, guarantee kiln thorax heat supply homogeneity, improved lime kiln performance.

Description

Lime kiln and heat supply method thereof

Technical Field

The application relates to the technical field of lime kilns, in particular to a lime kiln and a heat supply method thereof.

Background

The lime kiln is a core device in the lime production process, limestone raw materials are heated to 1100 ℃ in the lime kiln and calcined to generate a finished lime product, and fuel used for limestone calcination generally comprises coal gas and coal powder. Due to the different combustion characteristics of coal gas and pulverized coal, the type of fuel used in a particular lime kiln is generally fixed.

Fig. 1 is a schematic structural diagram of a conventional lime kiln, which comprises a kiln chamber 1 and a heat supply device, wherein the heat supply device comprises a fuel ring pipe 2 and a plurality of spray guns 31 connected with the fuel ring pipe 2, the spray guns 31 are uniformly distributed along the section of a calcining zone of the kiln chamber 1 so as to form a spray gun group 3, and each spray gun 31 in the spray gun group 3 is communicated with the inside of the kiln chamber 1. Limestone raw materials are loaded from the top of a kiln chamber 1, fuel is distributed to each spray gun 31 from a fuel ring pipe 2, the fuel is uniformly distributed to the inside of the kiln chamber 1 by each spray gun 31, combustion-supporting air is conveyed to the inside of the kiln chamber 1, the limestone raw materials are calcined and decomposed to generate calcium oxide and carbon dioxide waste gas under the action of gas combustion heat release, the carbon dioxide waste gas is discharged from the top of the kiln chamber 1, the temperature of finished calcium oxide is reduced to a preset discharging temperature under the action of cooling air at the bottom of the kiln chamber 1, and then the finished calcium oxide is discharged from the bottom of the kiln chamber 1, and quicklime production is completed.

In addition, although the spray guns 31 in the spray gun group 3 are uniformly distributed along the section of the calcining zone of the kiln chamber 1, the conventional lime kiln still has the problem of uneven heat supply, lime overburning occurs at a place with high temperature, lime unburning occurs at a place with low temperature, and the quality of the lime kiln product is influenced. The above factors severely restrict the performance of the lime kiln.

Disclosure of Invention

The application provides a lime kiln and a heat supply method thereof, which aim to solve the problem of poor performance of the existing lime kiln.

The lime kiln comprises a kiln chamber, a heating device and a combustion-supporting fan, wherein a combustion-supporting air pipe is communicated between the combustion-supporting fan and the kiln chamber, a combustion-supporting air stop valve is arranged on the combustion-supporting air pipe, the heating device comprises a fuel supply device and a spray gun group, the spray gun group is communicated with the interior of the kiln chamber, the spray gun group is provided with N spray guns in total, the fuel supply device comprises a coal gas supply device and a coal powder supply device, the coal gas supply device comprises a coal gas ring pipe and N coal gas branch pipes communicated with the coal gas ring pipe, each coal gas branch pipe is communicated with a feeding port end of one spray gun, the coal powder supply device comprises a coal powder ring pipe and N coal powder branch pipes communicated with the coal powder ring pipe, and each coal powder branch pipe is communicated with a feeding port end of one spray gun, so that the coal; a coal gas branch pipe regulating valve is arranged on each coal gas branch pipe, and a coal powder branch pipe regulating valve is arranged on each coal powder branch pipe; a flow detector is arranged on the spray gun; a first heat value detector and a first pressure detector are respectively arranged on the coal gas ring pipe, a second heat value detector is arranged on the coal powder ring pipe, and a second pressure detector is arranged inside the kiln chamber; the section of the kiln chamber is sequentially divided into a plurality of annular heat supply areas along the radial direction, the spray gun group comprises a plurality of spray gun matrixes, each spray gun matrix is correspondingly arranged in one annular heat supply area, and each spray gun matrix comprises a plurality of spray guns which are uniformly distributed along the circumference.

Combine the first aspect, in the first possible implementation of the first aspect, the spray gun includes the spray gun body, and the both ends of spray gun body are equipped with pan feeding mouth and discharge gate respectively, and the spray gun body includes that inlayer body and cover establish the outside outer body of inlayer body, is provided with interior fuel passageway in the inlayer body, forms annular outer fuel passageway between inlayer body and the outer body, and outer body is close to one section of discharge gate sets up a plurality of reposition of redundant personnel punch combinations along axial interval, reposition of redundant personnel punch combination includes a plurality of reposition of redundant personnel through-holes along circumference evenly distributed, and reposition of redundant personnel through-hole is the through-hole of downward sloping.

With reference to the first aspect or the first possible implementation manner of the first aspect, in a second possible implementation manner of the first aspect, the fuel supply device further includes N fuel switches, each fuel switch includes a gas inlet, a pulverized coal inlet and a fuel outlet, the gas inlet is communicated with the gas branch pipe, the pulverized coal inlet is communicated with the pulverized coal branch pipe, the fuel outlet is communicated with the material inlet end of the spray gun, and valve bodies are respectively disposed at the gas inlet and the pulverized coal inlet; the gas supply device also comprises a gas conveying fan, the gas conveying fan is communicated with the gas ring pipe through a gas conveying pipeline, and a gas stop valve is arranged on the gas conveying pipeline; the pulverized coal supply device also comprises a pulverized coal conveying fan, the pulverized coal conveying fan is communicated with the pulverized coal ring pipe through a pulverized coal conveying pipeline, and a pulverized coal cut-off valve is arranged on the pulverized coal conveying pipeline.

With reference to the second possible implementation manner of the first aspect, in a third possible implementation manner of the first aspect, the fuel supply device further includes a nitrogen purging device, the nitrogen purging device includes a nitrogen compression tank and a nitrogen ring pipe, the nitrogen ring pipe is communicated with N nitrogen branch pipes, the N nitrogen branch pipes are respectively provided with a nitrogen branch pipe regulating valve, the nitrogen compression tank and the nitrogen ring pipe are communicated through a nitrogen conveying pipeline, and the nitrogen conveying pipeline is provided with a nitrogen cut-off valve; the fuel switcher also comprises a nitrogen inlet which is communicated with the nitrogen branch pipe, the nitrogen inlet is provided with a valve body, and only one of the coal gas inlet, the coal powder inlet and the nitrogen inlet is communicated with the fuel outlet at the same moment by adjusting each valve body; when the nitrogen shut-off valve and the valve body at the nitrogen inlet are opened, the residual coal gas or coal powder in the fuel switcher is blown into the spray gun by the nitrogen.

With reference to the third possible implementation manner of the first aspect, in a fourth possible implementation manner of the first aspect, the valve body includes a rigid sealing ring, a sealing plug, and a return spring; a fixed supporting steel body is arranged in the center of the interior of the fuel switcher; the rigid sealing rings are respectively fixed on the peripheries of pipe orifices of the coal gas inlet, the coal powder inlet and the nitrogen inlet; one end of the reset spring is connected with the support steel body, and the other end of the reset spring is connected with the sealing plug; when the sealing plug is subjected to the pressure from the interior of the fuel switcher, the sealing plug is tightly pressed with the rigid sealing ring, so that the valve body is in a closed state; when the sealing plug is pressed from the outside of the fuel switcher, the return spring is compressed, and the sealing plug and the rigid sealing ring are separated, so that the valve body is in an open state.

With reference to the third possible implementation manner of the first aspect or the fourth possible implementation manner of the first aspect, in a fifth possible implementation manner of the first aspect, the gas supply device further includes a gas return pipeline, a gas return valve is disposed on the gas return pipeline, an outlet end of the gas return pipeline is communicated with an inlet end of the gas conveying fan, the inlet end of the gas return pipeline is communicated with the gas conveying pipeline, and the inlet end of the gas return pipeline is located between the gas cut-off valve and the outlet end of the gas conveying fan.

In combination with the fifth possible implementation manner of the first aspect, in the sixth possible implementation manner of the first aspect, the pulverized coal supply device further includes a pulverized coal backflow pipeline, a pulverized coal backflow valve is disposed on the pulverized coal backflow pipeline, an outlet end of the pulverized coal backflow pipeline is communicated with an inlet end of the pulverized coal conveying fan, the inlet end of the pulverized coal backflow pipeline is communicated with the pulverized coal conveying pipeline, and the inlet end of the pulverized coal backflow pipeline is located between the pulverized coal cutoff valve and the outlet end of the pulverized coal conveying fan.

In a second aspect, the present application provides a method for supplying heat to a lime kiln, for use in a lime kiln as set forth in the first aspect or in the first possible implementation manner of the first aspect, the method comprising:

when the pressure difference between the first pressure detector and the second pressure detector is greater than or equal to the minimum kiln entering pressure, the N coal powder branch regulating valves are closed, and the N coal gas branch regulating valves are opened, so that the N spray guns all convey coal gas fuel to the kiln chamber;

calculating the average gas supply W of each spray gun in the annular heat supply area_ijAdjusting the opening of each gas branch pipe adjusting valve to enable the measured value S of the flow detector_ijAnd W_ijMatching;

when the pressure difference is less than the minimum kiln entering pressure, calculating the switching number N_m；N_mThe number of theoretical spray guns for which fuel media need to be switched;

turning off N_xGas branch regulating valve, open N correspondingly_xA pulverized coal branch pipe regulating valve for regulating N in the spray gun group_xThe fuel conveyed by each spray gun is switched from coal gas to coal powder, N_xFor the actual number of lances required to switch the fuel medium, N_m≦N_x≦N；

Calculating a fuel supply amount T of each lance in the annular heat supply region_ijAdjusting said N_xRegulating valve for coal powder branch pipe and another N-N_xThe opening of the gas branch pipe regulating valve enables the measured value S of the flow detector _ijAnd T_ijMatching;

and opening a combustion-supporting air cut-off valve, improving the running frequency of a combustion-supporting fan, and enabling the combustion-supporting air quantity entering the kiln to be matched with the total fuel quantity, so that the switching process is finished.

Optionally, the calculating the number of handovers N_mThe method comprises the following steps:

according to the pressure difference between the first pressure detector and the second pressure detector, the maximum allowable number N of the gas spray guns in the spray gun group under the current gas loop pressure P1 is calculated_q；

Calculating the total number N of the spray guns and the maximum number N of the gas spray guns_qTo obtain the switching number N_m。

Optionally, the maximum number of gas lances N is calculated according to the following formula_q：

Where ρ is the gas density and v is_iDesign flow rate, h, for lance gas_tIs the coefficient of resistance of the gas ring pipe, h_iIs the coefficient of resistance, P, of the gas branch pipe₁Gas ring pipe pressure, P, measured for the first pressure detector₂α is a correction coefficient relating to the particle size of limestone particles inside the kiln chamber, which is the pressure inside the kiln chamber measured by the second pressure detector.

Optionally, in a third possible implementation manner of the first aspect, the method further includes:

presetting a plurality of uniform heat supply modes according to the total number N of the spray guns in the spray gun group and the distribution state of each spray gun on the section of the kiln chamber; the uniform heating mode is used for indicating N _mWhen the fuel medium is in the designated value range, the spray gun position of the spray gun group needing to switch the fuel medium and the actual spray gun number N_x。

Optionally, the number of handovers N is calculated_mThereafter, the method further comprises:

determining N_mA target uniform heat supply mode corresponding to the value range;

according to the indication of the target uniform heating mode, N of the corresponding part is calculated_xThe fuel medium of each spray gun is switched from coal gas to coal powder.

Optionally, the method further comprises:

marking each spray gun in the spray gun group in advance;

establishing N_mObtaining a uniform heat supply mode according to the corresponding relation between the value range and the spray gun set; the spray gun set comprises N spray gun groups_xThe number of individual lances that need to be switched over for the fuel medium.

Optionally, the method further comprises:

when a plurality of uniform heating modes are preset, determining a uniform heating threshold value N_y；

When the value range is as follows(N_y，N]When N is present_xN, so that the uniform heat supply mode supplies heat for single pulverized coal;

when the value range is (0, N)_y]Time, 0 < N_x≦N_yThe uniform heat supply mode supplies heat for the coal gas and the coal powder in a composite mode;

when the value range is 0, N_xEqual to 0, so that the uniform heat supply mode supplies heat for single coal gas.

Optionally, the total heat supply Q of the ring heating zone _iComprises the following steps:

Q₁＝Q÷ i＝1

Q_i＝Q×k_1i/ 2≤i≤Y

in the formula, Q₁The total heat supply quantity of a 1 st annular heat supply area is provided, and the 1 st annular heat supply area is positioned at the center of the section of the kiln chamber; q is the theoretical heat supply amount needed when the material is roasted under the height of a certain section of the kiln chamber; the heat transfer efficiency between the flue gas and the materials in the lime kiln is improved; k is a radical of_1iThe heating proportionality coefficient between the 1 st annular heating area and the ith annular heating area is calculated; y is the number of annular heating zones.

Alternatively, the average gas supply amount W of each lance in the annular heat supply region is calculated as follows_ij：

In the formula, Q_iFor total heat supply of the annular heating zone, X_iNumber of lances, h, included in the annular heating zone₁The specific heat value of the coal gas measured by the first heat value detector is more than or equal to 1 and less than or equal to j and less than or equal to X_i，1≦i≦Y。

Alternatively, the fuel supply T to each lance in the annular heating zone is calculated according to the following formula_ij：

In the formula, M_iFor annular heatingAverage heat supply per lance in a zone; q_iThe total heat supply for the annular heat supply area; x_iThe number of spray guns included in the annular heat supply area; for N in the on state_xSpray guns corresponding to the coal powder branch pipe regulating valve, h is h₂(ii) a For another N-N in the on state_xThe corresponding spray gun of the gas branch pipe regulating valve, h ═ h ₁(ii) a Wherein h is₁Specific calorific value of gas, h, measured by a first calorific value detector₂The unit heat value of the pulverized coal measured by the second heat value detector is more than or equal to 1 and less than or equal to j and less than or equal to X_i，1≦i≦Y。

With regard to the solution of the second aspect, the fuel supply device includes a gas supply device and a pulverized coal supply device, and the mutually independent gas supply device and pulverized coal supply device share a lance group, and each lance in the lance group is respectively communicated with one gas branch pipe and one pulverized coal branch pipe, so that the fuel medium delivered by each lance can be switched between gas and pulverized coal. During initial heat supply, the first pressure detector is used for measuring the pressure of the gas ring pipe, the second pressure detector is used for measuring the pressure inside the kiln chamber, when the pressure difference between the first pressure detector and the second pressure detector is larger than or equal to the minimum kiln entering pressure, the gas supply is sufficient, single gas is preferentially adopted for heat supply, and the average gas supply amount W of each spray gun in the annular heat supply area is calculated_ijAdjusting the opening of each gas branch pipe adjusting valve to enable the measured value S of the flow detector_ijAnd W_ijAnd matching to ensure the uniformity and accuracy of heat supply of the section of the kiln chamber.

In the heat supply process, if the pressure difference between the first pressure detector and the second pressure detector is smaller than the minimum kiln entering pressure, the coal gas pressure is shown to fluctuate, so that the pressure of a coal gas pipe network is too low, the coal gas pressure is not enough to support kiln entering, under the condition, the composite heat supply of coal gas and coal powder needs to be started, and the theoretical switching number N is calculated _mThen N in the gas supply is switched off_xA gas regulating valve for opening N in the pulverized coal supply device_xA pulverized coal regulating valve, wherein N_xGreater than or equal to N_mSo that there is at least N in the spray gun group_mThe fuel medium of each lance is switched from the original gas to coalPowder while ensuring additional N-N in the spray gun stack_xThe coal gas in each spray gun can be sprayed into the kiln chamber at a flow speed not lower than the design requirement, and the fuel medium of the designated spray gun can be automatically switched according to the pressure of the coal gas. Therefore, on the premise of first selecting single gas for heat supply, the method can ensure the stable operation of the lime kiln under the condition of low gas pressure, ensure the sufficient supply of the fuel medium in the kiln chamber, and the fuel medium of the lime kiln can be switched without being single, thereby improving the production stability and production adaptability of the lime kiln and being beneficial to the continuous and high-efficiency production of the lime kiln, in addition, the scheme divides the section of the lime kiln into a plurality of heat supply areas along the radial direction, and obtains the total heat supply quantity required by each heat supply area according to the difference of the heat dissipation quantity of each heat supply area, thereby accurately calculating and realizing the fuel supply quantity required by each independent spray gun, realizing accurate heat supply, uniformly heating the materials at different positions on the same horizontal section of the kiln chamber, avoiding overburning or unburning lime, thereby improve the quality of lime kiln product, consequently the performance of lime kiln can be showing to promote in this application.

In a third aspect, the present application provides a method for supplying heat to a lime kiln, which is used for the lime kiln according to the sixth possible implementation manner of the first aspect, and the method includes:

when the pressure difference between the first pressure detector and the second pressure detector is greater than or equal to the minimum kiln entering pressure, starting a single gas heat supply mode to enable all the N spray guns to convey gas fuel to the kiln chamber; the single coal gas heat supply mode is as follows: the coal gas shut-off valve, the coal gas conveying fan and the valve bodies at the coal gas inlets in the N fuel switchers are all in an open state, the coal powder shut-off valve and the valve bodies at the coal powder inlets in the N fuel switchers are all in a closed state, the coal powder conveying fan is in a standby state, and the nitrogen gas shut-off valve and the valve bodies at the nitrogen gas inlets in the N fuel switchers are all in a closed state; the coal gas return valve is in a closed state, and the coal powder return valve is in an open state; the N coal gas branch pipe regulating valves, the N coal powder branch pipe regulating valves and the N nitrogen branch pipe regulating valves are all in an open state;

calculating the average gas supply W of each spray gun in the annular heat supply area_ijRegulating the flow ofThe opening degree of each gas branch pipe regulating valve is saved, so that the measured value S of the flow detector_ijAnd W_ijMatching;

when the pressure difference is less than the minimum kiln entering pressure, calculating the switching number N _m；N_mThe number of theoretical spray guns for which fuel media need to be switched;

determining a uniform heating mode needing to be started, wherein the uniform heating mode is used for indicating N_mWhen the fuel medium is in the designated value range, the part of the spray gun group needing to switch the fuel medium and the actual number N of the spray guns_x，N_m≦N_x≦N；

Calculating a fuel supply amount T of each spray gun in the annular heat supply area after the uniform heat supply mode is started_ij；

Modulating N of said site_xThe opening degree of the coal powder branch pipe regulating valve corresponding to each spray gun and the other N-N_xThe opening degree of the gas branch pipe regulating valve corresponding to each spray gun enables the measured value S of each flow detector_ijAnd T_ijMatching;

Optionally, the method further comprises:

determining a uniform heat supply threshold value N according to the total number N of the spray guns in the spray gun group and the distribution state of each spray gun on the section of the kiln chamber_y；

When the value range is (N)_y，N]When N is present_xN, so that the uniform heat supply mode supplies heat for single pulverized coal;

Optionally, when the uniform heating mode supplies heat to the single pulverized coal, the uniform heating mode is started as follows:

sequentially closing valve bodies and gas stop valves at gas inlets in the N fuel switchers, and simultaneously opening a gas return valve to adjust the gas conveying and supplying machine to a standby state;

sequentially opening a nitrogen stop valve and valve bodies at nitrogen inlets in the N fuel switchers, and sequentially closing the valve bodies at the nitrogen inlets in the N fuel switchers and the nitrogen stop valve after the nitrogen blows residual pulverized coal in the fuel switchers to a spray gun;

close the buggy backward flow valve, improve buggy conveying fan's operating frequency, after buggy pressure reached the kiln requirement of entering, open the valve body of buggy trip valve and the buggy import department in N fuel switch in proper order, make the buggy in proper order through buggy conveying pipeline, buggy ring canal, N buggy branch pipe, the buggy import and the fuel outlet of N fuel switch and N spray gun, flow into inside the kiln thorax, then the even heat supply mode starts the completion.

Optionally, when the uniform heating mode is combined heating of coal gas and pulverized coal, the uniform heating mode is started as follows:

Turn off the rest of N-N_xA pulverized coal branch pipe regulating valve and a nitrogen branch pipe regulating valve corresponding to each spray gun, and simultaneously, closing N of the parts_xA gas branch regulating valve corresponding to each spray gun, and N for closing the part_xA valve body at the coal gas inlet of the fuel switcher corresponding to each spray gun;

sequentially opening nitrogen cut-off valve and N of the position_xThe valve body at the nitrogen inlet of the fuel switcher corresponding to each spray gun is used for sequentially closing N of the part after the nitrogen blows residual coal gas in the fuel switcher to the spray gun_xA valve body and a nitrogen shut-off valve 35 at the nitrogen inlet of the fuel switcher corresponding to each spray gun;

closing the coal powder reflux valve to improve the running frequency of the coal powder conveying fan, and opening the coal powder cut-off valve and the N of the part in sequence after the coal powder pressure reaches the requirement of entering the kiln_xThe valve body at the coal powder inlet of the fuel switcher corresponding to each spray gun makes the coal powder pass through the coal powder conveying pipeline, the coal powder ring pipe and the N_xCoalPowder branch pipe, N_xPulverized coal inlet and fuel outlet of individual fuel switch, and N_xAnd the spray gun flows into the kiln chamber.

according to the pressure difference between the first pressure detector and the second pressure detector, the maximum allowable number N of the gas spray guns in the spray gun group under the current gas loop pressure P1 is calculated _q；

Optionally, the total heat supply Q of the ring heating zone_iComprises the following steps:

Q₁＝Q÷ i＝1

Q_i＝Q×k_1i/ 2≤i≤Y

Alternatively, each injection in the annular heating zone is calculated according to the following formulaAverage gas supply W of the lance_ij：

In the formula, Q_iFor total heat supply of the annular heating zone, X _iNumber of lances, h, included in the annular heating zone₁The specific heat value of the coal gas measured by the first heat value detector is more than or equal to 1 and less than or equal to j and less than or equal to X_i，1≦i≦Y。

In the formula, M_iAverage heat supply for each lance in the annular heat supply zone; q_iThe total heat supply for the annular heat supply area; x_iThe number of spray guns included in the annular heat supply area; n for said site_xA spray gun, h ═ h₂For another N-N_xA spray gun, h ═ h₁(ii) a Wherein h is₁Specific calorific value of gas, h, measured by a first calorific value detector₂The unit heat value of the pulverized coal measured by the second heat value detector is more than or equal to 1 and less than or equal to j and less than or equal to X_i，1≦i≦Y。

And for the scheme of the third aspect, a coal gas supply device and a pulverized coal supply device are adopted in parallel, and the fuel switching control of the lime kiln is realized through a fuel switcher. During initial heat supply, the first pressure detector is used for measuring the pressure of the gas ring pipe, the second pressure detector is used for measuring the pressure inside the kiln chamber, when the pressure difference between the first pressure detector and the second pressure detector is larger than or equal to the minimum kiln entering pressure, the gas supply is sufficient, a single gas heat supply mode is preferentially adopted, and the average gas supply quantity W of each spray gun in the annular heat supply area is calculated _ijAdjusting the opening of each gas branch pipe adjusting valve to enable the measured value S of the flow detector_ijAnd W_ijAnd matching to ensure the uniformity and accuracy of heat supply of the section of the kiln chamber.

At the start ofAfter the single gas heat supply mode, if the pressure difference between the first pressure detector and the second pressure detector is smaller than the minimum kiln entering pressure, the gas pressure is fluctuated, so that the pressure of a gas pipe network is too low, and the gas pressure is not enough to support kiln entering, and under the condition, the heat supply mode is switched. Calculating the theoretical number of switching N_mAnd determining the uniform heat supply mode to be started next, wherein the uniform heat supply mode is preset according to the total number N of the spray guns in the spray gun group and the distribution state of each spray gun on the section of the kiln chamber in consideration of the uniformity of heat supply to the chamber, and only the N is calculated_mThen N can be found_mThe position of the spray gun to which the fuel needs to be switched corresponding to the value range and the actual number N of the spray guns_x. The coal gas inlet, the coal powder inlet and the nitrogen inlet inside the fuel switcher are respectively provided with a valve body, only the valve body at one inlet is opened at the same time, and other valve bodies are in a closed state, so that coal gas entering a coal powder ring pipe or coal powder entering the coal gas ring pipe due to mutual communication among the inlets is avoided, and fuel mixing caused by fuel backflow in a kiln chamber can be avoided, so that effective cutting-off of coal gas and coal powder is realized. The coal powder supply device and the coal gas supply device are combined and isolated through the fuel switcher, and by controlling the opening and closing state of each valve in the lime kiln and the running state of the fan, can quickly, automatically and flexibly switch the lime kiln fuel medium, realize diversified heat supply modes, thereby overcoming the defects of single type of heat supply fuel and poor production adaptability of the lime kiln, in addition, the scheme divides the section of the lime kiln into a plurality of heat supply areas along the radial direction, and obtains the total heat supply quantity required by each heat supply area according to the difference of the heat dissipation quantity of each heat supply area, thereby accurately calculating and realizing the fuel supply quantity required by each independent spray gun, realizing accurate heat supply, uniformly heating the materials at different positions on the same horizontal section of the kiln chamber, avoiding overburning or unburning lime, thereby improve the quality of lime kiln product, consequently the performance of lime kiln can be showing to promote in this application.

Drawings

FIG. 1 is a schematic structural diagram of a prior lime kiln;

FIG. 2 is a schematic view of the overall structure of a lime kiln according to an embodiment of the present application;

FIG. 3 is a structural diagram of a heating device of a lime kiln according to an embodiment of the present application;

FIG. 4 is a schematic diagram illustrating the division of the annular heat supply area on the section of the kiln chamber according to the first embodiment of the present application;

FIG. 5 is a distribution diagram of the spray guns in the spray gun group on the section of the kiln chamber according to the first embodiment of the application;

FIG. 6 is a distribution diagram of gas and pulverized coal injection lances in various homogeneous heating modes according to an embodiment of the present application;

FIG. 7 is a schematic view of the overall structure of a lime kiln according to the third embodiment of the present application;

FIG. 8 is a schematic view of a partial structure of a lime kiln according to a third embodiment of the present application;

fig. 9 is a schematic structural diagram of a fuel switch according to a third embodiment of the present application;

FIG. 10 is a schematic structural diagram of another fuel switch according to the third embodiment of the present application;

FIG. 11 is a schematic structural view of a spray gun body according to the fifth embodiment of the present application;

FIG. 12 is a circumferential cross-sectional view of a segment of the lance body adjacent the outlet as shown in example five of the present application;

FIG. 13 is a schematic view of the application range of the spray gun according to the fifth embodiment of the present application.

Detailed Description

In order to make those skilled in the art better understand the technical solutions in the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings.

As shown in fig. 2 and fig. 3, the lime kiln provided by the embodiment of the present application includes a kiln chamber 1, a heating device and a combustion fan 2, the heating device is used for supplying and conveying fuel required for calcining limestone to the kiln chamber 1, a combustion air pipe 21 is communicated between the combustion fan 2 and the kiln chamber 1, a combustion air cut-off valve 22 is arranged on the combustion air pipe 21, when the combustion fan 2 is started, and when the combustion air cut-off valve 22 is opened, combustion air can enter the kiln chamber 1 through the combustion air pipe 21, so as to provide combustion air for fuel combustion heat release.

In the present embodiment, the heat supply device includes a fuel supply device and a spray gun group 3, the spray gun group 3 is communicated with the inside of the kiln chamber 1, the spray gun group 3 is used for conveying the fuel provided by the fuel supply device to the inside of the kiln chamber 1, the spray gun group 3 has N spray guns 31 in total, that is, the total number of the spray guns 31 in the spray gun group 3 is N. The fuel supply device comprises a coal gas supply device 4 and a coal powder supply device 5, wherein the coal gas supply device 4 comprises a coal gas ring pipe 401 and N coal gas branch pipes 402 communicated with the coal gas ring pipe 401, each coal gas branch pipe 402 is communicated with a material inlet end of one spray gun 31, the coal powder supply device 5 comprises a coal powder ring pipe 501 and N coal powder branch pipes 502 communicated with the coal powder ring pipe 501, each coal powder branch pipe 502 is communicated with the material inlet end of one spray gun 31, and the coal gas supply device 4 and the coal powder supply device 5 share the spray gun group 3; a coal gas branch pipe regulating valve 403 is arranged on each coal gas branch pipe 402, and a coal powder branch pipe regulating valve 503 is arranged on each coal powder branch pipe 502; a flow detector 311 is arranged on the spray gun 31; the coal gas ring pipe 401 is respectively provided with a first heat value detector 404 and a first pressure detector 405, the coal powder ring pipe 501 is provided with a second heat value detector 504, and the interior of the kiln chamber 1 is provided with a second pressure detector 11.

Because the existing lime kiln can only use one of coal gas or pulverized coal fuel, if the type of the fuel needs to be changed, the flexibility is very poor only by modifying a heating system of the lime kiln. In addition, although the cost of lime kilns built in steel plants is low, coal gas is used as a byproduct of processes such as iron making and steel making, the supply is unstable, the gas quantity and the heat value of the coal gas are often greatly fluctuated, the production stability is difficult to ensure only by using the coal gas as a single fuel, and the lime production cost is increased by using only coal powder as a single fuel. Therefore, the heat supply fuel of the existing lime kiln is single, the fuel types can not be flexibly switched according to the working condition adaptability in the steel plant, the production adaptability of the lime kiln is poor, and the performance of the lime kiln is low.

In this embodiment, on the basis of the structure of the lime kiln shown in fig. 1, the heat supply device includes a parallel gas supply device and a parallel coal powder supply device, the mutually independent gas supply device and coal powder supply device share the spray gun group 3, the number of the gas branch pipes 402 and the number of the coal powder branch pipes 502 are equal to the number of the spray guns 31 included in the spray gun group 3, and are N, so that each spray gun 31 in the spray gun group 3 is respectively communicated with one gas branch pipe 402 and one coal powder branch pipe 502, and the gas branch pipe regulating valve 403 and the coal powder branch pipe regulating valve 503 corresponding to one single spray gun 31 are not opened at the same time, thereby preventing the gas branch pipes 402 from being communicated with the coal powder branch pipes 502, and ensuring that each spray gun.

For a single spray gun 31, when a coal powder branch pipe regulating valve 503 arranged on a coal powder branch pipe 502 communicated with the spray gun 31 is closed and a coal gas branch pipe regulating valve 403 arranged on a coal gas branch pipe 402 communicated with the spray gun 31 is opened, the fuel medium conveyed by the spray gun 31 is coal gas; when the coal gas branch pipe regulating valve 403 on the coal gas branch pipe 402 communicated with the coal gas branch pipe is closed and the coal powder branch pipe regulating valve 503 arranged on the coal powder branch pipe 502 communicated with the coal gas branch pipe is opened, the fuel medium conveyed by the spray gun 31 is coal powder. In this embodiment, the switching of the fuel medium delivered by each spray gun 31 between the coal gas and the coal powder can be rapidly controlled by adjusting the opening and closing states of the coal gas branch pipe regulating valve 403 and the coal powder branch pipe regulating valve 503, so that the problems that the existing lime kiln has single fuel and the fuel medium is flexibly switched according to the production condition of the lime kiln are effectively solved, and the production adaptability of the lime kiln is improved.

The coal gas fuel is used as a byproduct of processes of iron making, steel making and the like, and has the advantages of low cost, simple combustion device and the like compared with pulverized coal fuel, so that the coal gas fuel is used as a preferred fuel when the coal gas pressure meets the condition of entering the lime kiln and the initial heat supply of the lime kiln. During initial heating, the gas loop pressure P is measured using the first pressure gauge 405 ₁Measuring the pressure P inside the kiln chamber by using a second pressure detector 11₂When the pressure difference delta P between the two is larger than or equal to the minimum kiln entering pressure delta P_minWhen the pressure difference delta P is detected to be smaller than the minimum kiln entering pressure delta P in the single gas heat supply process, the single gas heat supply is preferentially adopted_minThe gas pressure is illustrated to fluctuate, so that the pressure of the gas pipe network is too lowIf the pressure of the coal gas is not enough to support the lime kiln, the fuel medium conveyed by part or all of the spray guns 31 in the spray gun group 3 can be switched from the coal gas to the coal powder, so that the stable operation of the lime kiln is ensured.

With the existing lime kilns as shown in fig. 1, the applicant found in the production practice that, on the one hand, the resistance coefficients of the lances are not uniform due to the differences in the manufacturing process of the lances and the different installation positions of the lances, resulting in uneven distribution of the fuel among the lances, and such unevenness cannot be corrected due to the lack of necessary detection and adjustment means, resulting in uneven distribution of the fuel over the firing section of the kiln chamber. On the other hand, theoretically, the heat dissipation capacity of each part of the section of the kiln chamber is different, correspondingly, in order to maintain the same temperature, the theoretical heat supply capacity required by each part of the section of the kiln chamber is different, the heat dissipation capacity at the center of the section of the kiln chamber is the minimum, and the theoretical heat supply capacity is also the minimum; and the heat dissipation perimeter at the edge of the section of the kiln chamber is the largest, and the heat dissipation capacity is the largest, so the theoretical heat supply capacity is also the largest. Due to the restriction of the two factors, even if the spray guns 31 in the spray gun group 3 are uniformly distributed along the section of the kiln chamber 1, accurate and uniform heat supply cannot be really provided for the lime kiln.

For this, the section of the kiln chamber 1 of the present embodiment is sequentially divided into a plurality of annular heat supply areas along the radial direction, for example, in fig. 4, the section is sequentially divided into 4 annular heat supply areas from inside to outside, which are respectively R1, R2, R3 and R4, wherein R1 is located at the center of the section of the kiln chamber 1, and R4 is located at the edge of the section of the kiln chamber 1; as shown in fig. 5, the spray gun group 3 includes a plurality of spray gun matrixes, each spray gun matrix is correspondingly arranged in an annular heat supply area, each spray gun matrix includes a plurality of spray guns 31 which are uniformly distributed along the circumference, for example, in fig. 5, the spray gun matrix of the annular heat supply area R1 includes 1 spray gun 31, the spray gun matrix of the annular heat supply area R2 includes 8 spray guns 31, the spray gun matrix of the annular heat supply area R3 includes 8 spray guns 31, the spray gun matrix of the annular heat supply area R4 includes 16 spray guns 31, and the total number of the spray guns in the spray gun group 3 is 33, that is, N is 33.

After the annular heat supply area division is completed, each area can be accurately determined according to different heat dissipating capacity of each areaTotal heat supply Q required in individual ring heat supply area_iThe fuel supply amount of each spray gun 31 can be accurately adjusted by matching with the first heat value detector 404, the second heat value detector 504, the coal gas branch pipe regulating valve 403, the coal powder branch pipe regulating valve 503 and the flow detector 311. Each lance 31 in the lance group 3 may be pre-numbered, for example in the form of a number qij, i being a number used to characterise the annular heating zone, j being a number used to characterise a lance in the matrix of lances within the zone, for example the lance numbered q23 in R2, to identify the lance number three in the second annular heating zone (R2), thereby facilitating accurate identification and control of each lance 31.

Taking the spray gun numbered Q23 in the annular heat supply area R2 as an example, the total heat supply amount of the annular heat supply area R2 is Q₂And the spray gun matrix in R2 includes 8 spray guns 31, the average heat supply S of each spray gun 31₂＝Q₂The first calorific value detector 404 is used for measuring the unit calorific value h of the gas₁The second heat value detector 504 is used for measuring the unit heat value h of the pulverized coal₂(ii) a When the lance numbered q23 delivers gas fuel, the fuel supply T is₂₃＝S₂/h₁Then, the opening of the gas branch regulating valve 403 corresponding to the spray gun q23 is regulated to make the measured value S of the flow detector 311 of the spray gun q23₂₃And T₂₃Matching; if the lance numbered q23 delivers pulverized coal fuel, the fuel supply T is determined₂₃＝S₂/h₂Then, the opening degree of the pulverized coal branch regulating valve 503 corresponding to the spray gun q23 is regulated to make the measured value S of the flow detector 311 of the spray gun q23₂₃And T₂₃And (4) matching. Therefore, the fuel supply quantity required by each spray gun 31 can be accurately obtained according to the heat dissipation quantity difference of each annular heat supply area, so that accurate and uniform heat supply of the lime kiln is realized, and the performance of the lime kiln is improved. In practical applications, the lime kiln of an embodiment may further comprise a computer control unit configured to perform the program steps as described in example two below.

An embodiment of the present application specifically provides a heat supply method for a lime kiln, which is used for the lime kiln according to the embodiment one, and the method includes the following program steps:

and S101, when the pressure difference between the first pressure detector and the second pressure detector is larger than or equal to the minimum kiln entering pressure, closing the N coal powder branch pipe regulating valves, and opening the N coal gas branch pipe regulating valves to enable the N spray guns to completely convey coal gas fuel to a kiln chamber.

And acquiring the gas loop pressure P1 through the first pressure detector 405 and acquiring the kiln chamber internal pressure P2 through the second pressure detector 11, wherein the differential pressure delta P is P1-P2, and the differential pressure delta P is a key parameter for judging whether the gas pressure meets the kiln entering condition. Then judging whether the delta P is more than or equal to the minimum kiln entering pressure delta P_minIf Δ P is greater than or equal to Δ P_minIf the gas pressure meets the condition of entering the kiln, the single gas heat supply mode can be started preferentially, and the single gas heat supply mode is as follows: the N coal powder branch pipe regulating valves 503 are all in a closed state, and the N coal gas branch pipe regulating valves 403 are all in an open state.

Step S102, calculating the average gas supply W of each spray gun in the annular heat supply area_ijAdjusting the opening of each gas branch pipe adjusting valve to enable the measured value S of the flow detector _ijAnd W_ijAnd (6) matching.

In the single gas heating mode, N spray guns 31 all convey gas into the kiln chamber 1, namely the fuel medium of each spray gun is the same, and the average gas supply W of each spray gun in the annular heating area is calculated according to the following formula_ij：

Q_iFor total heat supply of the annular heating zone, X_iNumber of lances, h, included in the annular heating zone₁The specific heat value of the coal gas measured by the first heat value detector is more than or equal to 1 and less than or equal to j and less than or equal to X _i1 ≦ i ≦ Y, Y being the number of annular heating zones. For the heating zone division diagram shown in FIG. 5, the R1 zone corresponds to X₁X corresponding to region 1, R2₂X corresponding to region 8, R3₃X corresponding to region 8, R4₄＝16。

Wherein, the total heat supply Q of the annular heat supply area_iComprises the following steps:

Q₁＝Q÷ i＝1

Q_i＝Q×k_1i/ 2≤i≤Y

in the formula, Q₁The total heat supply quantity of a 1 st annular heat supply area is provided, and the 1 st annular heat supply area is positioned at the center of the section of the kiln chamber; q is the theoretical heat supply amount needed when the material is roasted under the height of a certain section of the kiln chamber; the heat transfer efficiency between the flue gas and the materials in the lime kiln is improved; k is a radical of_1iThe heating proportionality coefficient between the 1 st annular heating area and the ith annular heating area is obtained. Since the 1 st annular heating zone (i.e. R1) is located at the center of the cross-section of the kiln chamber 1 and the heat dissipation is minimal, it is preferred to use it as a reference zone to calculate the total heat Q of the other annular heating zones _iI is greater than 1.

For the four annular heating zones shown in fig. 4, R1-R4 are calculated as follows, the total heating load for each zone being:

Q₁＝Q÷ i＝1

Q₂＝Q₁×k₁₂＝Q×k₁₂/

Q₃＝Q₁×k₁₃＝Q×k₁₃/

Q₄＝Q₁×k₁₄＝Q×k₁₄/

wherein k is₁₂The heating proportionality coefficient between R1 and R2 is different between R1 and R2 in the section of the kiln chamber and the heat dissipation amount is different, so that the total heating amount required by the two is different, and k is different₁₂The scale factor is used for representing the differentiation, and the value range of the scale factor is 1.15-1.3;

k₁₃the heating proportionality coefficient between R1 and R3 is different between R1 and R3 in the section of the kiln chamber and the heat dissipation amount is different, so that the total heating amount required by the two is different, and k is different₁₄The scale factor is used for representing the differentiation, and the value range of the scale factor is 1.3-1.5;

k₁₄the heating proportionality coefficient between R1 and R4 is different between R1 and R4 in the section of the kiln chamber and the heat dissipation amount is different, so that the total heating amount required by the two is different, and k is different₁₃Namely, the scale factor for representing the differences has a value range of 1.5-1.75.

Calculating the average gas supply W of each lance in the annular heat supply zone_ijThen, the opening degree of the gas branch regulating valve 403 corresponding to each spray gun 31 in the synchronous region can be adjusted so that the measured value S of the flow rate detector of each spray gun 31 is measured _ijAnd W_ijAnd matching, finishing the accurate heat supply regulation in the single gas heat supply mode. It should be noted that the division manner of the annular heating area is not limited to the embodiment and shown in fig. 4, and therefore k is_1iThe selection can be carried out according to a specific area division mode, and in other possible implementation modes, the annular heat supply area corresponding to the middle section or the edge of the section of the kiln chamber can be used as a reference area to obtain the differentiated proportionality coefficient between the reference area and other annular heat supply areas.

Step S103, when the pressure difference is smaller than the minimum kiln entering pressure, calculating the switching number N_m；N_mThe theoretical number of lances that need to switch the fuel medium.

After the single gas heating mode is started, whether the pressure difference delta P is larger than or equal to the minimum kiln entering pressure delta P or not still needs to be detected in real time_minIf yes, the gas pressure meets the kiln entering condition, and the current single gas heat supply state is kept; if the pressure difference delta P is less than the minimum kiln entering pressure delta P_minIf the pressure of the gas pipe network is not enough to support the coal entering the kiln, part or all of the fuel medium of the spray gun 31 needs to be switched from gas to coal powder.

Further, when the gas pressure does not satisfy the kiln entering condition, the maximum number N of gas spray guns allowed in the spray gun group 3 under the current gas ring pipe pressure P1 can be calculated according to the pressure difference Δ P _qAnd calculating the total number N of the spray guns and the maximum number N of the gas spray guns in the spray gun group 3_qTo obtain the switching number N_mI.e. N_m＝N-N_q。

According to the fluid mechanics theory, the pressure drop of the gas pipeline is calculated by the formula (a):

in the formula (a), rho is the gas density; v. of_tThe flow rate of the gas in the gas ring pipe; v. of_iDesigning the flow rate for the gas of the spray gun; h is_tThe resistance coefficient of the gas ring pipe; h is_iIs the resistance coefficient of the gas branch pipe. In the heating device of the lime kiln, because the working condition coal gas flow velocity is larger than 20m/s, the fluid in the pipe is in an excessive turbulent flow zone, and h is at the moment_iAnd h_tAre two constants independent of the gas flow rate.

Since the geometrical dimensions and other conditions of the respective lances 31 are the same, the gas flow velocity v of the gas in the gas loop pipe is the same when the gas flow velocity of the respective lances 31 is the same_tCan be calculated according to the following equation (b):

v_t＝N_q·v_i(b)

in summary, further:

the maximum number of gas lances N allowed in the lance group 3 can be determined from the formula (c)_qComprises the following steps:

in practice, the applicant has found that unlike other combustion devices, the lance 31 of a lime kiln is generally arranged buried inside a bed of limestone in which the fuel is burnt directly, which results in the need to overcome not only the resistance of the duct but also the additional resistance of the bed when the fuel is ejected from the lance 31. The resistance of the material layer to the fuel is related to the particle size and porosity of the material below the spray gun 31, and for the working condition of the lime kiln, the material at the spray gun 31 is a mixture of limestone raw material and calcium oxide powder, so that the corresponding resistance is difficult to accurately calculate. In order to ensure that the flow rate of the fuel sprayed from the spray gun 31 is not lower than the design requirement, a correction coefficient alpha related to the particle size of limestone material particles is multiplied on the basis of the formula (d) in the embodiment, and specifically, as shown in the formula (e), the correction coefficient alpha is a series of values smaller than 1 obtained through practical production experience.

The correction coefficient α is related to the particle size of limestone material particles, and specific values thereof can be referred to as shown in table 1 below.

TABLE 1

Limestone average particle size	＜30mm	30mm-40mm	40mm-60mm	＞60mm
					Correction factor alpha	0.4	0.6	0.75	0.8

Due to N_qOnly integer can be taken, and simultaneously, in order to ensure that the flow rate of the spray gun gas is not lower than the design requirement, N obtained by calculation of the formula (e) is used_qRounding down to obtain formula (f):

calculating the maximum number of gas lances N allowed in the lance group 3 by means of the formula (f)_qThen using N_m＝N-N_qCalculating the theoretical number of handovers N_m。

Step S104, closing N_xGas branch regulating valve, open N correspondingly_xA pulverized coal branch pipe regulating valve for regulating N in the spray gun group_xThe fuel conveyed by each spray gun is switched from coal gas to coal powder, N_xFor the actual number of lances required to switch the fuel medium, N_m≦N_x≦N。

During the operation of the single gas heating mode, if the pressure difference delta P is detected to be less than the minimum kiln entering pressure delta P_minThen the theoretical number of handovers N needs to be calculated_mThen N in the gas supply is switched off_xA gas branch pipe regulating valve 403 for opening N in the pulverized coal supply device_xA pulverized coal branch regulating valve 503, wherein N_xGreater than or equal to N_mSo that there is at least N in the spray gun group 3_mThe fuel medium of each spray gun 31 is switched from the original coal gas to the coal powder, and the other N-N in the spray gun group 3 is ensured _xThe coal gas in each spray gun 31 can be sprayed into the kiln chamber 1 at a flow speed not lower than the design requirement, and the fuel medium of the designated spray gun 31 can be automatically switched according to the pressure of the coal gas. It can be seen that on the premise of preferably selecting single gas for heat supply, the stable operation of the lime kiln can be ensured under the condition of low gas pressure, and the sufficient supply of fuel media in the kiln chamber is ensured, so that the production stability and the production adaptability of the lime kiln are improved, the continuous and efficient production of the lime kiln is facilitated, and the performance of the lime kiln is improved.

However, different fuels are adopted for composite heat supply, when one part of the spray guns in the spray gun group 3 conveys coal gas and the other part of the spray guns conveys coal powder, because the heat supply characteristics such as the heat intensity and the action range of different fuel media are different, the difference of the heat supply temperature of the spray guns at different positions in the kiln chamber 1 is large, the temperature distribution in the kiln chamber 1 is uneven, and the quality of the lime kiln product is affected.

To this end, in this embodiment, the method further includes: presetting a plurality of uniform heat supply modes according to the total number N of the spray guns in the spray gun group 3 and the distribution state of each spray gun 31 on the section of the kiln chamber 1; the uniform heating mode is used for indicating N _mWhen the fuel medium is in the designated value range, the spray gun position of the spray gun group 3 needing to be switched and the actual spray gun number N_x. Determining N_mThe target uniform heat supply mode corresponding to the value range is positioned, and then according to the indication of the target uniform heat supply mode, the N of the corresponding part is_xThe fuel medium of each spray gun is switched from coal gas to coal powder.

When presetting a plurality of uniform heating modes, firstly, determining a uniform heating threshold value N_yThreshold value N for uniform heat supply_yCan be determined according to the total number N of the spray guns and the distribution state of each spray gun on the section of the kiln chamber, when N is_mGreater than N_yIn the process, if coal gas and coal powder are adopted for composite heat supply, the uniformity of temperature distribution in the kiln chamber cannot be ensured.

When the value range is (N)_y，N]When N is present_xEqual to N, so that the uniform heat supply mode supplies heat for single pulverized coal;

when the value range is (0, N)_y]Time, 0 < N_x≦N_yThe uniform heat supply mode is to supply heat for the coal gas and the coal powder;

when the value range is 0, N_xEqual to 0, so that the uniform heat supply mode supplies heat for single gas.

Fig. 5 illustrates thirty-three spray guns 31 in the spray gun group 3, and spray gun matrixes are respectively arranged in four annular heat supply areas, wherein the spray gun matrix in the first annular heat supply area R1 comprises one spray gun 31, the spray gun matrix in the second annular heat supply area R2 comprises eight spray guns 31, the spray gun matrix in the third annular heat supply area R3 comprises eight spray guns 31, and the spray gun matrix in the fourth annular heat supply area R4 comprises sixteen spray guns 31, so that the structure can ensure that the thirty-three spray guns are uniformly distributed on the section of the kiln chamber 1, and the uniform distribution of the temperature of the kiln chamber is facilitated. The embodiment shows the distribution of the spray gun groups 3 Seven uniform heating modes, as shown in table 2 below, the uniform heating threshold N corresponding to the structure of the spray gun group_yAnd 9, wherein the uniform heat supply mode 1 is a single coal gas heat supply mode, the uniform heat supply modes 2-6 are coal gas and coal powder composite heat supply modes, and the uniform heat supply mode 7 is a single coal powder heat supply mode.

TABLE 2

N_mValue range of	Uniform heating mode
		N_m＝0	1
N_m＝1	2
		1＜N_m≤4	3
N_m＝5	4
		5＜N_m≤8	5
N_m＝9	6
		9＜N_m≤33	7

When N is present_mWhen equal to 0Corresponding to the uniform heating mode 1, as shown in fig. 6(a), in the uniform heating mode 1, the number of the gas injection lances is 33, and the number of the pulverized coal injection lances is 0, that is, N_xAnd (0) performing a heat supply mode by using gas as a single fuel medium.

When N is present_mWhen the number of the coal gas injection lances is 1, the number of the coal gas injection lances is 32 and the number of the coal powder injection lances is 1 in the uniform heating mode 2, that is, N, as shown in fig. 6(b) of fig. 6, which corresponds to the uniform heating mode 2_xThe pulverized coal injection lance is 1 injection lance at the center of the first annular heat supply area (namely the injection lance position needing to switch the fuel medium).

When 1 < N_mWhen the number of the coal gas spray guns is less than or equal to 4, the coal gas spray guns correspond to the uniform heat supply mode 3, as shown in 6(c) in figure 6, in the uniform heat supply mode 3, the number of the coal gas spray guns is 29, and the number of the coal powder spray guns is 4, namely N_xAnd 4, the pulverized coal spray guns are distributed at intervals in the spray gun matrix of the second annular heat supply area.

When N is present_mWhen the number is 5, the uniform heating mode 4 is corresponded, as shown in fig. 6(d), in the uniform heating mode 4, the number of the gas injection lances is 28, and the number of the pulverized coal injection lances is 5, that is, N_xAnd 5, 4 pulverized coal injection guns are distributed in the injection gun matrix of the third annular heat supply area at intervals, and the other 1 pulverized coal injection gun is the injection gun at the center of the first annular heat supply area.

When 5 < N_mWhen the number is less than or equal to 8, the number corresponds to the uniform heat supply mode 5, as shown in 6(e) in fig. 6, in the uniform heat supply mode 5, the number of the coal gas spray guns is 25, and the number of the coal powder spray guns is 8, namely N_xThe pulverized coal injection guns are all 8 injection guns of the injection gun matrix of the second annular heat supply area.

When N is present_mWhen the number is 9, the uniform heating mode 6 is corresponded, as shown in fig. 6(f), in the uniform heating mode 6, the number of the gas injection lances is 24, and the number of the pulverized coal injection lances is 9, that is, N _x8 of the pulverized coal injection guns are all the injection guns of the injection gun matrix of the third annular heat supply area, and the other 1 pulverized coal injection gun is the injection gun at the center of the first annular heat supply area.

When 9 < N_mWhen less than or equal to 33, namely N_mGreater than the uniform heat supply threshold N_yCorresponding uniform heat supplyMode 7, as shown in 6(g) of FIG. 6, in the uniform heat supply mode 7, the number of coal gas injection lances is 0, and the number of pulverized coal injection lances is 33, that is, N _x33, when the gas pressure is too low, the maximum number of gas lances N allowed in the lance group 3_qAnd if a coal gas and coal powder composite heat supply mode is still adopted, the temperature in the kiln chamber 1 cannot be ensured to be uniform, so the heat supply mode taking the coal powder as a single fuel medium is selected.

It should be noted that, in this embodiment and fig. 6, an optional uniform heating mode is shown when 33 spray guns are distributed according to fig. 5, and for different spray gun component distribution structures, the uniform heating threshold value can be adaptively determined according to actual situations and the corresponding uniform heating mode can be set, which is not limited in this application.

In order to facilitate the control of the uniform heating mode, in other optional solutions of this embodiment, the method further includes: marking each spray gun in the spray gun group in advance; establishing N_mThe value range and the corresponding relation of the spray gun set to obtain the uniform heat supply mode, wherein the spray gun set comprises N spray gun groups_xThe number of individual lances that need to be switched over for the fuel medium. For example, referring to fig. 5, the number of each spray gun may be sequentially numbered according to the distribution of the spray gun matrix, the number of the spray gun matrix in the first annular heat supply region is q11, the number of each spray gun in the second annular heat supply region is q21 to q28 in a clockwise sequence, the number of each spray gun in the third annular heat supply region is q31 to q38 in a clockwise sequence, and the number of each spray gun in the fourth annular heat supply region is q41 to q416 in a clockwise sequence.

According to the example of uniform heating mode given in fig. 6, the uniform heating mode can be expressed as:

uniform heating mode 1 is N_m0 and { empty set };

uniform heating mode 2 is N _m1 to { q11 };

the uniform heat supply mode 3 is more than 1 and less than N_mThe corresponding relation between the number less than or equal to 4 and { q21, q23, q25 and q27 };

uniform heating mode 4 is N_mA correspondence of 5 to { q11, q31, q33, q35, q37 };

the uniform heat supply mode 5 is more than 5N_mThe corresponding relation between the number less than or equal to 8 and { q21, q22, q23, q24, q25, q26, q27 and q28 };

uniform heating mode 6 is N_m(iii) a correspondence of 9 to { q11, q31, q32, q33, q34, q35, q36, q37, q38 };

the uniform heat supply mode 7 is that N is more than 9_m33 or less and { corpus } is used.

For example, when N is calculated_mWhen the temperature is 3, the uniform heating mode 3 is determined, and the corresponding spray gun set is inquired to be { q21, q23, q25 and q27}, the gas branch regulating valve 403 corresponding to the spray guns with the numbers q21, q23, q25 and q27 in the spray gun group 3 is closed, and the coal powder branch regulating valve 503 corresponding to the spray guns with the numbers q21, q23, q25 and q27 in the spray gun group 3 is opened, so that the fuel media of the spray guns with the numbers q21, q23, q25 and q27 are switched from coal gas to coal powder, and the spray guns corresponding to the numbers not included in the spray gun set { q21, q23, q25 and q27} still convey coal gas fuel.

Step S105, calculating the fuel supply quantity T of each spray gun in the annular heat supply area_ijAdjusting said N_xRegulating valve for coal powder branch pipe and another N-N_xThe opening of the gas branch pipe regulating valve enables the measured value S of the flow detector_ijAnd T_ijAnd (6) matching.

Refer to the total heating amount Q of each ring heating district shown in step S102_iOn the basis of which the fuel supply T to each lance in the annular heating zone is calculated according to the following formula_ijThe fuel is coal gas or coal powder:

in the formula, M_iAverage heat supply for each lance in the annular heat supply zone; q_iThe total heat supply for the annular heat supply area; x_iThe number of spray guns included in the annular heat supply area; for N in the on state_xSpray guns corresponding to the coal powder branch pipe regulating valve, h is h₂(ii) a For another N-N in the on state_xThe corresponding spray gun of the gas branch pipe regulating valve, h ═ h₁(ii) a Wherein h is₁Specific calorific value of gas, h, measured by a first calorific value detector₂The unit heat value of the pulverized coal measured by the second heat value detector is more than or equal to 1 and less than or equal to j and less than or equal to X_i，1≦i≦Y。

Taking the above-mentioned uniform heating mode 4 as an example for explanation, the uniform heating mode 4 has indicated the locations of the lances that need to switch the fuel medium and the actual number of lances N _x，N_xWhen 5 lances supply pulverized coal fuel to the furnace chamber, the fuel supply amount T of 5 lances (numbered q11, q31, q33, q35, and q37, respectively) at the corresponding positions was calculated_ijI.e. the amount of coal dust supplied, the amount of fuel supplied to the lance q11 being T₁₁Then the opening of the coal dust branch regulating valve 503 corresponding to the spray gun q11 is regulated to make the measured value S of the flow detector of the spray gun q11₁₁And T₁₁And the pulverized coal flow of the spray guns of q31, q33, q35 and q37 is adjusted in a matching way. At the same time, for another N-N not included in the set of { q11, q31, q33, q35, q37}, the spray guns_xFor a lance, e.g. q32, which delivers fuel which is still gas, the fuel supply is calculated as T₃₂That is, the gas supply amount, the opening degree of the gas branch regulating valve 403 corresponding to the q32 lance is adjusted so that the measured value S of the flow rate detector of the q32 lance is set to be equal to the value S measured by the gas branch regulating valve 403 corresponding to the q32 lance₃₂And T₃₂Matching and adjusting other N-N similarly_xGas flow of 1 lance, so that the entire lance group 3 provides precise heating of the kiln chamber 1.

And step S106, opening a combustion-supporting air cut-off valve, increasing the running frequency of a combustion-supporting fan, and enabling the combustion-supporting air quantity entering the kiln to be matched with the total fuel quantity, so that the switching process is finished.

After the fuel flow of each spray gun 31 in the spray gun group 3 is completely adjusted, the operating frequency of the combustion fan 2 is increased, the combustion fan 2 is started, the combustion air cut-off valve 22 is opened, the combustion air enters the kiln chamber 1 through the combustion air duct 21, the combustion air quantity is matched with the total fuel quantity delivered by the N spray guns in the spray gun group 3, the fuel switching process of the spray gun group 3 is finished, and the limestone in the kiln chamber 1 can be calcined to obtain the finished lime.

In the embodiment, on the premise of preferably selecting single gas for heat supply, the stable operation of the lime kiln can be ensured under the condition of low gas pressure, the sufficient supply of the fuel medium in the kiln chamber is ensured, the fuel medium of the lime kiln can be switched without being single, thereby improving the production stability and production adaptability of the lime kiln and being beneficial to the continuous and high-efficiency production of the lime kiln, in addition, the scheme divides the section of the lime kiln into a plurality of heat supply areas along the radial direction, and obtains the total heat supply quantity required by each heat supply area according to the difference of the heat dissipation quantity of each heat supply area, thereby accurately calculating and realizing the fuel supply quantity required by each independent spray gun, realizing accurate heat supply, uniformly heating the materials at different positions on the same horizontal section of the kiln chamber, avoiding overburning or unburning lime, thereby improving the quality of the lime kiln product, and the scheme can obviously improve the performance of the lime kiln.

As shown in fig. 7-9, a lime kiln according to another embodiment of the present application is provided, in addition to the structure of the lime kiln according to the first embodiment, the fuel supply device further includes N fuel switchers 6, the fuel switchers 6 correspond to the lances 31 one by one, fig. 7-9 only show the connection structure of one group of fuel switchers 6 and lances 31, and the connection structure of the remaining N-1 groups of fuel switchers 6 and lances 31 is the same, and therefore is not shown. The fuel switcher 6 is used for combining and isolating the coal gas supply device 4 and the coal powder supply device 5 from each other, so that the lime kiln can realize switching the fuel from coal gas to coal powder and switching the fuel from coal powder to coal gas, and mixed flow between the coal gas and the coal powder in the lime kiln can be avoided. Limestone raw materials are loaded into the kiln chamber 1 through the distributor 8, the spray gun 31 is used for spraying switched fuel (coal gas or coal powder) into the kiln chamber 1, then the combustion-supporting air cut-off valve 22 is opened, combustion-supporting air conveyed by the combustion-supporting fan 2 enters the kiln chamber 1 through the combustion-supporting air pipe 21, and the fuel is combusted to supply heat for calcining limestone so as to generate a lime finished product.

Each fuel switcher 6 comprises a coal gas inlet 61, a coal powder inlet 62 and a fuel outlet 64, wherein the coal gas inlet 61 is communicated with the coal gas branch pipe 402, the coal powder inlet 62 is communicated with the coal powder branch pipe 502, the fuel outlet 64 is communicated with the material inlet end of the spray gun 31, and the coal gas inlet 61 and the coal powder inlet 62 are respectively provided with a valve body 65; the gas supply device 4 further comprises a gas conveying fan 406, the gas conveying fan 406 is communicated with the gas ring pipe 401 through a gas conveying pipeline 407, and a gas stop valve 408 is arranged on the gas conveying pipeline 407; the coal powder supply device 5 further comprises a coal powder delivery fan 505, the coal powder delivery fan 505 is communicated with the coal powder ring pipe 501 through a coal powder delivery pipeline 506, and a coal powder shut-off valve 507 is arranged on the coal powder delivery pipeline 506.

In the gas supply pipeline, a gas delivery fan 406, a gas delivery pipe 407 and a gas ring pipe 401 form a gas main pipeline, and N gas branch circuits are generated from the gas ring pipe 401, and each gas branch circuit comprises a gas branch pipe 402, a fuel switcher 6 and a spray gun 31 which correspond to each other in sequence. When the gas cut-off valve 408 is in an open state and the gas conveying fan 406 normally works, the gas main pipeline is conducted, and the N gas branches are also conducted together, so that gas fuel is conveyed to the kiln chamber 1; when the gas stop valve 408 is in a closed state and the running frequency of the gas conveying fan 406 is lowered to a standby state, the whole gas supply pipeline is cut off, and gas is not supplied to the kiln chamber 1.

Similarly, in the coal powder supply pipeline, the coal powder delivery fan 505, the coal powder delivery pipe 506 and the coal powder loop pipe 501 form a coal powder main pipeline, and N coal powder branches are generated from the coal powder loop pipe 501, and each coal powder branch comprises a coal powder branch pipe 502, a fuel switcher 6 and a spray gun 31 which correspond to each other in sequence. When the coal dust cut-off valve 507 is in an open state and the coal dust conveying fan 505 normally works, the coal dust main pipeline is conducted, and the N coal dust branches are also conducted together, so that coal dust fuel is conveyed to the kiln chamber 1; when the coal powder cut-off valve 507 is in a closed state and the running frequency of the coal powder conveying fan 505 is reduced to a standby state, the whole coal powder supply pipeline is cut off, and at the moment, the coal powder is not supplied to the kiln chamber 1 any more.

Referring to fig. 9, taking the example that the lance 31 delivers the pulverized coal to the kiln chamber 1, the operating principle of the fuel switching 6 is explained, the valve body 65 at the pulverized coal inlet 62 is opened, and the valve body 65 at the coal gas inlet 61 is closed, so as to prevent the pulverized coal fuel from the pulverized coal branch pipe 502 from entering the coal gas supply pipeline through the coal gas inlet 61, and thus prevent the pulverized coal and the coal gas from mixing. At this time, only the pulverized coal inlet 62 is communicated with the fuel outlet 64, and pulverized coal flows in from the pulverized coal inlet 62, flows out from the fuel outlet 64, and then enters the lance 31. At the same time, only one of the coal gas inlet 61 and the pulverized coal inlet 62 is communicated with the fuel outlet 64, so that the pulverized coal and the coal gas are isolated. The valve body 65 may be a solenoid valve or other type of fluid control valve, and is not limited in this application.

Since the cross-sectional area of the fuel switch 6 is larger than the diameter of each inlet (the gas inlet 61, the pulverized coal inlet 62 and the nitrogen inlet 63), a small portion of the fuel may not be sufficiently discharged from the fuel outlet 64, resulting in a possibility of fuel remaining in the fuel switch 6. In addition, since the fuel outlet 64, the lance 31 and the kiln chamber 1 are communicated with each other, there may also occur a case where the fuel in the kiln chamber 1 flows back into the fuel switcher 6. For example, when it is required to switch the fuel of the lime kiln from gas to pulverized coal, because there may be residual gas in the fuel switcher 6, once the valve body 65 at the pulverized coal inlet 62 is opened, the residual gas may enter the pulverized coal supply pipeline from the pulverized coal inlet 62, resulting in the mixture of gas and pulverized coal, i.e. there is no effective isolation and cut-off of gas and pulverized coal. On one hand, if the mixed flow of the coal gas and the coal powder enters the kiln chamber 1, the combustion characteristics of the coal gas and the coal powder are different, the uniformity of the temperature distribution of a calcining zone in the kiln chamber 1 is influenced, and the product quality of the lime kiln is influenced; on the other hand, if the coal powder and the coal gas are mixed, explosion is also easily caused, so that potential safety hazards exist in the production of the lime kiln.

In contrast, in a preferred embodiment of the present invention, the fuel supply device further includes a nitrogen purging device 7, the nitrogen purging device 7 includes a nitrogen compression tank 71 and a nitrogen ring pipe 72, the nitrogen ring pipe 72 is communicated with N nitrogen branch pipes 73, the N nitrogen branch pipes 73 are respectively provided with a nitrogen branch pipe regulating valve 74, the nitrogen compression tank 71 and the nitrogen ring pipe 72 are communicated through a nitrogen conveying pipeline 75, and the nitrogen conveying pipeline 75 is provided with a nitrogen shut-off valve 76; the fuel switcher 6 also comprises a nitrogen inlet 63, the nitrogen inlet 63 is communicated with a nitrogen branch pipe 73, a valve body 65 is arranged at the nitrogen inlet 63, and only one of the coal gas inlet 61, the coal powder inlet 62 and the nitrogen inlet 63 is communicated with the fuel outlet 64 at the same time by adjusting each valve body 65; when the nitrogen shut-off valve 76 and the valve body 65 at the nitrogen inlet 63 are opened, the residual gas or pulverized coal in the fuel switch 6 is blown into the lance 31 by the nitrogen gas.

In the nitrogen supply line, the nitrogen compression tank 71, the nitrogen delivery pipe 75 and the nitrogen collar 72 constitute a nitrogen main line, and N nitrogen branches including the nitrogen branch pipes 73, the fuel switch 6 and the lance 31 are generated from the nitrogen collar 72 in sequence. When the nitrogen shut-off valve 76 is in an open state, the nitrogen main pipeline is conducted, the N nitrogen branches are also conducted, the valve bodies 65 at the nitrogen inlets 63 in the N fuel switchers 6 are opened, and the nitrogen blows the residual fuel in the fuel switchers 6 into the spray gun 31 and returns to the kiln chamber 1 through the spray gun 31; after the purging is finished, the nitrogen shut-off valve 76 and the valve body 65 at the nitrogen inlet 63 are closed, the whole nitrogen supply pipeline is cut off, the previous work of the switching process is finished, and the fuel can be switched based on the coal gas supply pipeline or the coal powder supply pipeline. Because nitrogen is inert gas and has no flammability, the fuel is blown into the kiln chamber 1 by nitrogen, the combustion of the fuel is not influenced, the explosion risk is avoided, the effective separation of coal powder and coal gas is realized by arranging the nitrogen blowing device 7, and the production safety of the lime kiln is improved.

In a preferred embodiment of the present invention, as shown in fig. 10, the present embodiment further provides a specific structure of a valve body 65, and unlike an electronic control valve, the valve body 65 includes a rigid sealing ring 651, a sealing plug 652 and a return spring 653; a fixed supporting steel body 66 is arranged in the center of the interior of the fuel switcher 6; the rigid sealing rings 651 are respectively fixed on the peripheries of pipe orifices of the coal gas inlet 61, the coal powder inlet 62 and the nitrogen inlet 63; one end of the return spring 653 is connected to the support steel body 66, and the other end is connected to the sealing plug 652; when the sealing plug 652 receives pressure from the inside of the fuel switch 6, the sealing plug 652 is tightly pressed against the rigid sealing ring 651, so that the valve body 65 is in a closed state; when the sealing plug 652 receives a pressure from the outside of the fuel switch 6, the return spring 653 is compressed, and the sealing plug 652 and the rigid seal ring 651 are separated, so that the valve body 65 is in an open state.

Taking the example that the spray gun 31 delivers the pulverized coal into the kiln chamber 1, the pulverized coal delivery air from the pulverized coal branch pipe 502 has a certain pressure, and when passing through the pulverized coal inlet 62, the sealing plug 652 is pushed from the outside, and the return spring 653 is compressed, so that the pulverized coal inlet 62 is opened, and the pulverized coal inlet 62 is communicated with the fuel outlet 64, and it can be seen that, for the valve body 65 at the pulverized coal inlet 62, the pressure of the pulverized coal delivery air from the pulverized coal branch pipe 502 on the sealing plug 652 belongs to the pressure from the outside of the fuel switcher 6; when the pulverized coal conveying air enters the inside of the fuel switcher 6 from the pulverized coal inlet 62, the air pressure of the pulverized coal conveying air can make the sealing plugs 652 at the gas inlet 61 and the nitrogen inlet 63 press the rigid sealing rings 651, so that the tightness of the gas inlet 61 and the nitrogen inlet 63 is ensured, and the sealing plugs 652 at the gas inlet 61 and the nitrogen inlet 63 are subjected to the pressure from the inside of the fuel switcher 6.

The supporting steel body 66 is arranged in the center of the fuel switcher 6 and is fixed, one end of the reset spring 653 is connected with the supporting steel body 66, the other end of the reset spring 653 is connected with the sealing plug 652, the sealing plug 652 can move along with the extension and contraction of the reset spring 653, after the fuel is conveyed, the reset spring 653 resets to drive the sealing plug 652 to be in compression joint with the rigid sealing ring 651, so that the opening and closing of the coal gas inlet 61, the coal powder inlet 62 and the nitrogen inlet 63 are controlled, and the inlets are prevented from being communicated with one another. A rigid sealing ring 651 is arranged around each inlet, the diameter of the rigid sealing ring 651 being slightly larger than the diameter of the inlet, and the sealing plug 652 being dimensioned larger than the diameter of the rigid sealing ring 651 to ensure sealing performance of each inlet. If the rigid sealing ring 651 is not arranged, the sealing plug 652 directly blocks the inlet of the fuel switcher 6, the sealing performance of the surface contact sealing is poor, and the rigid sealing ring 651 and the sealing plug 652 are in compression joint, so that the valve body 65 has good sealing performance, and the fuel switching effect is ensured. The valve body shown in fig. 10 has a simple structure, can reduce the equipment cost of the lime kiln, automatically controls the opening and closing of the valve body 6 by spontaneously sensing the pressure from the inside and the outside of the fuel switcher 6 without sending an electric control signal for control, and improves the sealing performance and the control efficiency of the valve body 65.

When the fuel in the kiln chamber 1 flows back, the fuel may enter the inside of the fuel switch 6 from the fuel outlet 64, and then the sealing plugs 652 of the valve bodies 65 at the gas inlet 61, the coal powder inlet 62 and the nitrogen inlet 63 are all subjected to the pressure from the inside of the fuel switch 6, and the three valve bodies 65 can be in a closed state by matching with the return spring 653, and the three inlets of the fuel switch 6 have good sealing performance, so that the returned fuel cannot enter the gas branch pipe 402, the coal powder branch pipe 502 and the nitrogen branch pipe 73. When the fuel is switched, the nitrogen purge device 7 may be used to re-blow the returned fuel remaining in the fuel switch 6 to the lance 31 and to return the fuel to the kiln chamber 1 through the lance 31.

When fuel is switched, taking the example of switching fuel from coal gas to coal powder, after the coal gas cut-off valve 408 is closed, the coal gas main pipeline is cut off, and the coal gas conveying fan 406 cannot stop operating suddenly, but the operating frequency needs to be gradually reduced to a standby state, so that the pressure of the coal gas conveying pipeline 407 between the coal gas cut-off valve 408 and the coal gas conveying fan 406 is increased, and the safety of the coal gas supply pipeline is further affected. Similarly, the same problem exists with pulverized coal supply lines.

In view of this, in a preferred embodiment of the present invention, referring to fig. 7, the gas supply device 4 further includes a gas return pipe 409, the gas return pipe 409 is provided with a gas return valve 410, an outlet end of the gas return pipe 409 is communicated with an inlet end of the gas conveying fan 406, the inlet end of the gas return pipe 409 is communicated with the gas conveying pipe 407, and the inlet end of the gas return pipe 409 is located between the gas shutoff valve 408 and an outlet end of the gas conveying fan 406, so that when the gas return valve 410 is opened, the gas conveying air can circulate between the gas return pipe 409 and the gas conveying fan 406 to release the pressure of the gas conveying fan 406, thereby ensuring the safety of the gas supply pipe.

The pulverized coal supply device 5 further comprises a pulverized coal return pipeline 508, a pulverized coal return valve 509 is arranged on the pulverized coal return pipeline 508, the outlet end of the pulverized coal return pipeline 508 is communicated with the inlet end of the pulverized coal conveying fan 505, the inlet end of the pulverized coal return pipeline 508 is communicated with the pulverized coal conveying pipeline 506, and the inlet end of the pulverized coal return pipeline 508 is located between the pulverized coal shut-off valve 507 and the outlet end of the pulverized coal conveying fan 505. The lime kiln of embodiment three may further comprise a computer control unit configured to perform the procedural steps of embodiment four below.

An embodiment four of the present application provides a heat supply method for a lime kiln, which is used for the lime kiln structure as described in the embodiment three, and the method includes:

firstly, when the pressure difference between the first pressure detector and the second pressure detector is greater than or equal to the minimum kiln entering pressure, the coal gas pressure meets the kiln entering condition, and then a single coal gas heat supply mode is preferentially started, so that all the N spray guns convey coal gas fuel to a kiln chamber; the single coal gas heat supply mode is as follows: the coal gas shut-off valve 408, the coal gas conveying fan 406 and the valve bodies 65 at the coal gas inlets 61 of the N fuel switchers 6 are all in an open state, the coal powder shut-off valve 507 and the valve bodies 65 at the coal powder inlets 62 of the N fuel switchers 6 are all in a closed state, the coal powder conveying fan 505 is in a standby state, and the nitrogen shut-off valve 76 and the valve bodies 65 at the nitrogen inlets 63 of the N fuel switchers 6 are all in a closed state; the coal gas return valve 410 is in a closed state, and the coal powder return valve 509 is in an open state; the N coal gas branch regulating valves 403, the N pulverized coal branch regulating valves 503, and the N nitrogen branch regulating valves 74 are all in an open state. After the single heat supply mode is started, the equipment in each link in the supply device is in the state as described above, in this case, the second step is performed to adjust the gas flow rate of each spray gun 31 in the spray gun group 3, so as to realize accurate heat supply of the lime kiln.

Second, calculate the average gas supply W for each lance in the annular heat supply zone_ijAdjusting the opening of each gas branch pipe adjusting valve to enable the measured value S of the flow detector_ijAnd W_ijAnd (6) matching. For the precise heating flow adjustment manner described in step S202 and step S206, refer to the related description and description in the second embodimentObviously, this embodiment is not described in detail.

Thirdly, when the pressure difference is less than the minimum kiln entering pressure, the switching number N is calculated_m；N_mThe theoretical number of lances that need to switch the fuel medium. For this step, reference may be made to the related description and illustration in the second embodiment, which is not described again in this embodiment.

Fourthly, determining a uniform heating mode needing to be started, wherein the uniform heating mode is used for indicating N_mWhen the fuel medium is in the designated value range, the part of the spray gun group needing to switch the fuel medium and the actual number N of the spray guns_x，N_m≦N_x≦N。

Determining a uniform heat supply threshold value N according to the total number N of the spray guns in the spray gun group and the distribution state of each spray gun on the section of the kiln chamber_y. The distribution state of each spray gun on the section of the kiln chamber comprises the division mode of an annular heat supply area, the quantity of the spray guns in each annular heat supply area, the distribution position and the distribution state of each spray gun in a spray gun matrix, and the like.

Please refer to the description and explanation of the second embodiment of the present application, which will not be described again. After calculating the switching number N_mThen, it can be based on N_mAnd determining the uniform heating mode required to be adopted according to the value range.

In one possible implementation, when N_m＝N_xAnd (5) keeping the single gas heating mode operated by the current lime kiln unchanged, namely keeping the state mode described in the first step.

In another possible implementation manner, when it is determined that the uniform heating mode is to supply heat to single pulverized coal, that is, the fuel of all the N injection guns needs to be synchronously switched from coal gas to pulverized coal, in the state of the single coal gas heating mode, the uniform heating mode is started as follows:

(A) sequentially closing the valve bodies 65 and the gas stop valves 408 at the gas inlets 61 of the N fuel switchers 6, and simultaneously opening the gas return valves 410 to adjust the gas conveying fans 406 to a standby state; at this time, the whole gas supply line is cut off, the heating apparatus does not supply gas into the kiln chamber 1, and the gas return valve 410 is used to release the pressure of the gas supply fan 406.

(B) After the nitrogen shut-off valve 76 and the valve body 65 at the nitrogen inlet 63 of the N fuel switches 6 are sequentially opened, and the nitrogen blows the pulverized coal remaining inside the fuel switches 6 to the lance 31, the nitrogen blowing process is ended, and the valve body 65 at the nitrogen inlet 63 of the N fuel switches 6 and the nitrogen shut-off valve 76 are sequentially closed. At the moment, residual coal gas in the N fuel switchers 6 is removed, the possibility of mixing of coal powder and coal gas in the switching process is effectively avoided, the whole nitrogen supply pipeline can be cut off, and coal powder fuel is prepared to be subsequently conveyed to the kiln chamber 1.

(C) The coal powder reflux valve 509 is closed, the running frequency of the coal powder conveying fan 505 is improved, after the coal powder pressure meets the requirement of entering the kiln, namely, after the coal powder can be guaranteed to be injected into the kiln chamber 1 through the spray guns 31, the coal powder stop valve 507 and the valve body 65 at the coal powder inlet 62 of the N fuel switchers 6 are sequentially opened, so that the coal powder sequentially passes through the coal powder conveying pipeline 506, the coal powder ring pipe 501, the N coal powder branch pipes 502, the coal powder inlet 62 and the fuel outlet 64 of the N fuel switchers 6 and the N spray guns 31 and finally flows into the kiln chamber 1, the uniform heat supply mode is started and completed, and the fuel in the N spray guns 31 can be synchronously switched into the coal powder from the coal gas in the mode.

In another possible implementation manner, when the uniform heat supply mode is determined to supply heat for the coal gas and the pulverized coal compositely, the indication of the uniform heat supply mode can indicate which parts of the spray guns in the spray gun group 3 are switched from coal gas to pulverized coal and the need to switch the combustion is metActual number of spray guns N of the charge medium_xNamely, the fuel of part of the N spray guns is switched from coal gas to coal powder, and the uniform heat supply mode is started in the following mode under the state of the single coal gas heat supply mode:

(D) turn off the rest of N-N_xThe pulverized coal branch regulating valve 503 and the nitrogen branch regulating valve 74 corresponding to each lance (i.e., not the lance at the designated position in the homogeneous heating mode) are closed, and at the same time, N of the position (i.e., the position at which the lance designated in the homogeneous heating mode, which needs to switch fuel, is located) is closed_xGas branch regulating valve 403 corresponding to each lance, and N for closing the portion_xThe valve body 65 at the gas inlet 61 of the fuel switch 6 for each lance.

For the remaining N-N_xThe spray guns 31 are adjusted in the step (D), the corresponding coal powder branch and the nitrogen branch are cut off, and only the coal gas branch is still conducted, so that the N-N_xThe fuel medium sprayed out by each spray gun 31 is still coal gas and cannot be influenced by subsequent nitrogen purging and switching to coal powder, and the coal gas sequentially passes through a coal gas conveying pipeline 407, a coal gas ring pipe 401 and N-N _xA gas branch pipe 402, N-N_xGas inlet 61 and fuel outlet 64 of each fuel switch 6, and N-N_xA lance 31, which flows into the kiln chamber 1. N for said site_xThe corresponding gas branch of each spray gun 31 is cut off, and the nitrogen supply pipeline can be opened according to the following step (E) to purge residual gas in the fuel switcher 6, so that the spray guns 31 can not blow out mixed fuel of gas and coal powder.

(E) The nitrogen shut-off valve 76 and the N of the part are opened in sequence_xThe valve body 65 at the nitrogen inlet 63 of the fuel switcher 6 corresponding to each spray gun sequentially closes N at the part after the nitrogen blows the residual coal gas in the fuel switcher 6 to the spray gun 31_xThe valve body 65 and the nitrogen shut-off valve 76 at the nitrogen inlet 63 in the fuel switcher 6 correspond to each lance. When the nitrogen shut-off valve 76 is opened, the nitrogen main pipe is communicated, and nitrogen enters the N part of the part from the nitrogen ring pipe 72_xN corresponding to each spray gun 31_xA nitrogen branch is formed, and corresponding N is_xIndividual fuel switchingBlowing residual gas in the device 6 and then sending the gas into each spray gun 31, cutting off a nitrogen branch to prepare for the subsequent step (F), and carrying out the step (F) of enabling N at the position_xThe fuel of each lance 31 is switched from coal gas to coal powder.

(F) Closing the coal powder reflux valve 509 to improve the running frequency of the coal powder conveying fan 505, and opening the coal powder stop valve 507 and the N of the part in sequence after the coal powder pressure reaches the requirement of entering the kiln_xThe valve body 65 at the coal powder inlet 62 of the fuel switcher 6 corresponding to each spray gun makes the coal powder pass through the coal powder conveying pipeline 506, the coal powder ring pipe 501 and the N coal powder ring pipe in sequence_xCoal dust branch pipes 502 and N_xPulverized coal inlet 62 and fuel outlet 64 of each fuel switch 6, and N_xA lance 31, which finally flows into the interior of the kiln chamber 1.

In this embodiment, the coal gas transportation fan 406 and the pulverized coal transportation fan 505 may be operated normally at the same time, and the pulverized coal transportation fan 505 is used to move to N of the above-mentioned portion_xOne lance 31 delivers pulverized coal and the gas delivery fan 406 delivers another N-N_xThe spray guns 31 are used for conveying coal gas, and each spray gun 31 is provided with the corresponding coal gas branch pipe regulating valve 403, coal powder branch pipe regulating valve 503 and nitrogen gas branch pipe regulating valve 74, so that the coal gas supply device 4 and the coal powder supply device 5 can supply fuel simultaneously, and mutual interference is avoided, and the coal gas and coal powder composite heat supply can be realized.

In the above single gas heat supply mode, the gas and pulverized coal composite heat supply mode, and the single pulverized coal heat supply mode, the valve body 65 at the three inlets inside the fuel switcher 6 may adopt a valve body structure as shown in fig. 6, such as a conventional solenoid valve, etc., or may adopt a specially designed pressure-sensitive automatic regulating valve as shown in fig. 10, as long as the sealing and opening and closing of the three inlets inside the fuel switcher 6 can be realized.

Fifthly, after the uniform heat supply mode is started, the fuel supply quantity T of each spray gun in the annular heat supply area is calculated_ij。

Sixth, adjusting N of the site_xThe opening degree of the coal powder branch pipe regulating valve corresponding to each spray gun and the other N-N_xThe opening degree of the gas branch pipe regulating valve corresponding to each spray gun enables the measured value S of each flow detector_ijAnd T_ijAnd (6) matching.

And seventhly, opening a combustion-supporting air cut-off valve, improving the running frequency of a combustion-supporting fan, and enabling the combustion-supporting air quantity entering the kiln to be matched with the total fuel quantity, so that the switching process is finished.

It should be noted that, after the single gas heat supply is preferentially started, if the pressure difference between the first pressure detector and the second pressure detector is smaller than the minimum kiln entering pressure, the mode is switched to the coal gas and coal powder composite heat supply mode, or the mode is switched to the single coal powder heat supply mode, and in the non-single gas heat supply mode, whether the pressure difference is larger than or equal to the minimum kiln entering pressure still needs to be detected in real time. The application has disclosed the running state of each equipment and valve in the heating device under the single gas heating mode, if the gas pressure meets the condition of entering the kiln under the current non-single gas heating mode, the current heating mode can be selected to be switched back to the single gas heating mode, so as to reduce the fuel cost of the lime kiln. In addition, the running states of all equipment and valves in the heating device are adjusted, so that the interconversion among different heating modes can be realized, the actually required heating effect is achieved, and the production adaptability of the lime kiln is improved.

In the embodiment, the coal powder supply device and the coal gas supply device are combined and isolated through the fuel switcher, the lime kiln fuel medium can be switched rapidly, automatically and flexibly by controlling the opening and closing state of each valve in the lime kiln and the running state of the fan, diversified heat supply modes are realized, and the defects of single type of heat supply fuel and poor production adaptability of the lime kiln are overcome. Therefore, the performance of the lime kiln can be obviously improved.

For the lances as referred to in the above embodiments, because the spreading range of each lance has limitations, the fuel sprayed by the lance is mainly concentrated at the outlet of the lance, but the fuel is not distributed in the area between the lance and the lance, i.e. the fuel is not uniformly distributed on the section of the kiln chamber, which results in high material temperature at the outlet of the lance and relatively low material temperature in the area between the lance and the lance, so that limestone calcination rates on the same section of the kiln chamber are different, which affects the quality of the finished quicklime.

To this end, as shown in fig. 11 and 12, based on the solutions described in the foregoing embodiments, a fifth embodiment of the present invention specifically provides a structure of a spray gun 31, which includes a spray gun body 3101, an inlet 3102 and an outlet 3103 are respectively provided on the spray gun body 3101, the spray gun body 3101 includes an inner layer pipe body 3104 and an outer layer pipe body 3105, the outer layer pipe body 3105 is sleeved outside the inner layer pipe body 3104, the inner layer pipe body 3104 and the outer layer pipe body 3105 are both hollow pipe-shaped structures, an inner fuel channel 3106 is provided in the inner layer pipe body 3104, the diameter of the inner layer pipe body 3104 is smaller than that of the outer layer pipe body 3105, so as to form an annular outer fuel channel 3107 between the inner layer pipe body 3104 and the outer layer pipe body 3105, a plurality of branch hole sets 3108 are provided at intervals along an axial direction at a section of the outer layer pipe body 3105 close to the outlet 3103, and the branch hole. Generally, the calcining process temperature of the lime kiln is about 1100 ℃, and the spray gun body 3101 can be made of high-temperature resistant materials and can be selected according to actual application.

The lance provided by the embodiment is based on a double-channel structure, fuel (including coal gas, coal powder and the like) flows in from an inlet 3102, then respectively enters an inner fuel channel 3106 and an outer fuel channel 3107, and finally is sprayed out from an outlet 3103 and each shunt through hole 3109, wherein the outlet 3103 is a main outlet of a lance body 3101, most of the fuel is sprayed out through the main outlet, each shunt through hole 3109 arranged on an outer layer tube body 3105 is equivalent to an auxiliary outlet of the lance body, and a small part of the fuel flowing into the outer fuel channel 3107 is sprayed out through the shunt through hole 3109, so that the spreading range of a single lance is effectively increased, the fuel is distributed to the area between the lance and the lance, the uniformity of temperature distribution on the same section of a kiln chamber is ensured, and the quality of quick lime finished products.

In practical application, in order to facilitate the material guiding of the spray gun, the spray gun body can be divided into a horizontal section 3110, an arc transition section 3111 and a vertical section 3112, and the horizontal section 3110 is connected with the vertical section 3112 through the arc transition section 3111; inlet 3102 is disposed at an open end of horizontal segment 3110, such as the left end of horizontal segment 3110 in fig. 11; outlet 3103 is provided at an open end of vertical section 3112, such as at a bottom end of vertical section 3112 in fig. 11, and a plurality of groups 3108 are provided on outer tubular body 3105 of vertical section 3112. In practical applications, the horizontal segment 3110, the circular arc transition segment 3111 and the vertical segment 3112 may be integrally formed, or may be welded in different sections, which is not limited in this application.

As shown in FIG. 13, the spreading range of the existing lime kiln spray gun is only the corresponding area S1 below the outlet, and the sprayed fuel falls on the area where S1 is located, so that the fuel cannot be distributed between the spray gun and the area between the spray guns, and the temperature distribution of the section of the kiln chamber is uneven. The fuel flowing into the outer fuel passage 3107, as shown here, falls into the region of the vertical segment 3112 and exits through each of the flow splitting apertures 3109, thereby widening the fuel spreading range, which is greater than S1. In other possible implementations, the central axis of the inner tube 3104 coincides with the central axis of the outer tube 3105 to ensure more uniform and symmetrical spreading of the fuel flowing from the flow splitting apertures 3109; the tap hole 3109 is a downwardly inclined hole, i.e. the center axis of the tap hole 3019 is inclined at an angle β to the center axis of the vertical section 3112, such that the spray range of the lance is S1+ S2, where S1 is constant and S2 is the maximum spray range of several tap hole groups 3108, such as the tap hole group with the highest height in the vertical direction of fig. 13, which is the largest. The value of S2 is related to the design height and the inclination angle beta of the group 3108 of distribution holes, and the higher the height of the group 3108 of distribution holes and the larger the inclination angle beta, the larger S2 and the larger the spreading range of a single lance. Therefore, in practical applications, the size of the lance body 3101, the distribution of the branch hole group 3108 on the vertical section 3112, and the size of the inclination angle β can be designed according to the number of lances, the distribution state of the lances, the size of the hearth, and other parameters.

The spray gun based on the double channels provided by the embodiment has the advantages that the spreading range of the spray gun is not limited, the fuel spreading range is increased to be S1+ S2 from the original S1, the fuel spreading range can be applied to an outlet and can also be applied to the area between the spray gun and the spray gun, so that the fuel distribution is more in place and uniform, the temperature distribution of the section of the kiln chamber of the lime kiln is more uniform, the quality of a quick lime finished product is improved, and the performance of the lime kiln is improved.

The same and similar parts in the various embodiments are referred to each other in this specification.

The above-described embodiments of the present application do not limit the scope of the present invention.

Claims

1. A lime kiln comprises a kiln chamber (1), a heat supply device and a combustion-supporting fan (2), wherein a combustion-supporting air pipe (21) is communicated between the combustion-supporting fan (2) and the kiln chamber (1), a combustion-supporting air stop valve (22) is arranged on the combustion-supporting air pipe (21), the heat supply device comprises a fuel supply device and a spray gun group (3), the spray gun group (3) is communicated with the inside of the kiln chamber (1), the spray gun group (3) is provided with N spray guns (31) in total, the lime kiln is characterized in that the fuel supply device comprises a coal gas supply device (4) and a coal powder supply device (5), the coal gas supply device (4) comprises a coal gas ring pipe (401) and N coal gas branch pipes (402) communicated with the coal gas ring pipe (401), each coal gas branch pipe (402) is communicated with a feed port end of one spray gun (31), the coal powder supply device (5) comprises a coal powder ring pipe (501) and N coal powder branch pipes (502, each coal powder branch pipe (502) is communicated with a material inlet end of one spray gun (31), so that the coal gas supply device (4) and the coal powder supply device (5) share the spray gun group (3); a coal gas branch pipe regulating valve (403) is arranged on each coal gas branch pipe (402), and a coal powder branch pipe regulating valve (503) is arranged on each coal powder branch pipe (502); a flow detector (311) is arranged on the spray gun (31); a first heat value detector (404) and a first pressure detector (405) are respectively arranged on the coal gas circular pipe (401), a second heat value detector (504) is arranged on the coal powder circular pipe (501), and a second pressure detector (11) is arranged in the kiln chamber (1); the section of the kiln chamber is sequentially divided into a plurality of annular heat supply areas along the radial direction, the spray gun group (3) comprises a plurality of spray gun matrixes, each spray gun matrix is correspondingly arranged in one annular heat supply area, and each spray gun matrix comprises a plurality of spray guns (31) which are uniformly distributed along the circumference.

2. The lime kiln according to claim 1, wherein the lance (31) comprises a lance body (3101), a feeding port (3102) and a discharging port (3103) are respectively arranged at two ends of the lance body (3101), the lance body (3101) comprises an inner layer pipe body (3104) and an outer layer pipe body (3105) sleeved outside the inner layer pipe body (3104), an inner fuel channel (3106) is arranged in the inner layer pipe body (3104), an annular outer fuel channel (3107) is formed between the inner layer pipe body (3104) and the outer layer pipe body (3105), a plurality of distribution hole groups (3108) are axially arranged at intervals at one section of the outer layer pipe body (3105) close to the discharging port (3103), the distribution hole groups (3108) comprise a plurality of distribution through holes (3109) uniformly distributed along the circumference, and the distribution through holes (3109) are downward inclined through holes.

3. The lime kiln according to claim 1 or 2, wherein the fuel supply device further comprises N fuel switches (6), each fuel switch (6) comprises a coal gas inlet (61), a coal powder inlet (62) and a fuel outlet (64), the coal gas inlet (61) is communicated with the coal gas branch pipe (402), the coal powder inlet (62) is communicated with the coal powder branch pipe (502), the fuel outlet (64) is communicated with the material inlet end of the lance (31), and the coal gas inlet (61) and the coal powder inlet (62) are respectively provided with a valve body (65); the gas supply device (4) also comprises a gas conveying fan (406), the gas conveying fan (406) is communicated with the gas ring pipe (401) through a gas conveying pipeline (407), and a gas stop valve (408) is arranged on the gas conveying pipeline (407); the coal powder supply device (5) further comprises a coal powder conveying fan (505), the coal powder conveying fan (505) is communicated with the coal powder ring pipe (501) through a coal powder conveying pipeline (506), and a coal powder cut-off valve (507) is arranged on the coal powder conveying pipeline (506).

4. The lime kiln according to claim 3, wherein the fuel supply device further comprises a nitrogen purging device (7), the nitrogen purging device (7) comprises a nitrogen compression tank (71) and a nitrogen ring pipe (72), the nitrogen ring pipe (72) is communicated with N nitrogen branch pipes (73), N nitrogen branch pipes (73) are respectively provided with a nitrogen branch pipe regulating valve (74), the nitrogen compression tank (71) and the nitrogen ring pipe (72) are communicated through a nitrogen conveying pipeline (75), and the nitrogen conveying pipeline (75) is provided with a nitrogen shut-off valve (76); the fuel switcher (6) further comprises a nitrogen inlet (63), the nitrogen inlet (63) is communicated with the nitrogen branch pipe (73), a valve body (65) is arranged at the nitrogen inlet (63), and only one of the coal gas inlet (61), the coal powder inlet (62) and the nitrogen inlet (63) is communicated with the fuel outlet (64) at the same time by adjusting each valve body (65); when the nitrogen shut-off valve (76) and the valve body (65) at the nitrogen inlet (63) are opened, the residual coal gas or coal powder in the fuel switcher (6) is blown into the lance (31) by the nitrogen.

5. Lime kiln according to claim 4, characterized in that the valve body (65) comprises a rigid sealing ring (651), a sealing plug (652) and a return spring (653); a fixed supporting steel body (66) is arranged in the center of the interior of the fuel switcher (6); the rigid sealing rings (651) are respectively fixed on the peripheries of pipe orifices of the coal gas inlet (61), the coal powder inlet (62) and the nitrogen inlet (63); one end of the return spring (653) is connected with the supporting steel body (66), and the other end is connected with the sealing plug (652); when the sealing plug (652) receives pressure from the inside of the fuel switcher (6), the sealing plug (652) is tightly pressed with the rigid sealing ring (651), so that the valve body (65) is in a closed state; when the sealing plug 652 receives a pressure from the outside of the fuel switch 6, the return spring 653 is compressed, and the sealing plug 652 and the rigid seal ring 651 are separated, so that the valve body 65 is in an open state.

6. The lime kiln according to claim 4 or 5, characterized in that the gas supply device (4) further comprises a gas return line (409), the gas return line (409) being provided with a gas return valve (410), the outlet end of the gas return line (409) being in communication with the inlet end of the gas delivery fan (406), the inlet end of the gas return line (409) being in communication with the gas delivery line (407), and the inlet end of the gas return line (409) being located between the gas shut-off valve (408) and the outlet end of the gas delivery fan (406), the gas delivery air being circulated between the gas return line (409) and the gas delivery fan (406) to release the pressure of the gas delivery fan (406) when the gas return valve (410) is opened.

7. The lime kiln according to claim 6, characterized in that the pulverized coal supply device (5) further comprises a pulverized coal return pipe (508), a pulverized coal return valve (509) is arranged on the pulverized coal return pipe (508), the outlet end of the pulverized coal return pipe (508) is communicated with the inlet end of the pulverized coal conveying fan (505), the inlet end of the pulverized coal return pipe (508) is communicated with the pulverized coal conveying pipe (506), and the inlet end of the pulverized coal return pipe (508) is located between the pulverized coal shut-off valve (507) and the outlet end of the pulverized coal conveying fan (505), when the pulverized coal return valve (509) is opened, pulverized coal conveying air is made to circularly flow between the pulverized coal return pipe (508) and the pulverized coal conveying fan (505) so as to release the pressure of the pulverized coal conveying fan (505).

8. A method for supplying heat to a lime kiln according to claim 1 or 2, characterized in that the method comprises:

Calculating a fuel supply amount T of each lance in the annular heat supply region_ijAdjusting said N_xRegulating valve for coal powder branch pipe and another N-N_xThe opening of the gas branch pipe regulating valve enables the measured value S of the flow detector_ijAnd T_ijMatching;

9. The method of claim 8, wherein the calculating the number of handovers N_mThe method comprises the following steps:

10. Method according to claim 9, characterized in that the maximum number of gas lances N is calculated according to the following formula_q：

11. The method according to any of claims 8-10, characterized in that the method further comprises:

according to the total number N of the spray guns in the spray gun group and the total number N of the spray guns in the kiln chamberThe distribution state on the cross section is preset with a plurality of uniform heat supply modes; the uniform heating mode is used for indicating N _mWhen the fuel medium is in the designated value range, the spray gun position of the spray gun group needing to switch the fuel medium and the actual spray gun number N_x。

12. Method according to claim 11, characterized in that the number of handovers N is calculated_mThereafter, the method further comprises:

13. The method of claim 11, further comprising:

marking each spray gun in the spray gun group in advance;

14. The method of claim 11, further comprising:

15. According to claim 8The method is characterized in that the total heat supply Q of the annular heat supply area_iComprises the following steps:

Q₁＝Q÷ i＝1

Q_i＝Q×k_1i/ 2≤i≤Y

16. The method of claim 15, wherein the average gas supply W for each lance in the annular heat supply zone is calculated according to the following formula_ij：

17. The method of claim 15, wherein the fuel supply T to each lance in the annular heating zone is calculated according to the formula_ij：

In the formula, M _iAverage heat supply for each lance in the annular heat supply zone; q_iThe total heat supply for the annular heat supply area; x_iThe number of spray guns included in the annular heat supply area; for N in the on state_xCoal powder branch pipe regulating valveCorresponding spray gun, h ═ h₂(ii) a For another N-N in the on state_xThe corresponding spray gun of the gas branch pipe regulating valve, h ═ h₁(ii) a Wherein h is₁Specific calorific value of gas, h, measured by a first calorific value detector₂The unit heat value of the pulverized coal measured by the second heat value detector is more than or equal to 1 and less than or equal to j and less than or equal to X_i，1≦i≦Y。

18. A method of supplying heat to a lime kiln according to claim 7, characterized in that the method comprises:

After the uniform heat supply mode is started, calculating each annular heat supply areaFuel supply T of individual lance_ij；

19. The method of claim 18, further comprising:

determining a uniform heat supply threshold value N according to the total number N of the spray guns in the spray gun group and the distribution state of each spray gun on the section of the kiln chamber _y；

20. The method of claim 19, wherein when the homogeneous heating mode supplies heat to the single pulverized coal, the homogeneous heating mode is activated as follows:

21. The method of claim 19, wherein when the uniform heating mode is a coal gas and pulverized coal combined heating mode, the uniform heating mode is activated as follows:

closing the coal powder reflux valve to improve the running frequency of the coal powder conveying fan, and opening the coal powder cut-off valve and the N of the part in sequence after the coal powder pressure reaches the requirement of entering the kiln_xThe valve body at the coal powder inlet of the fuel switcher corresponding to each spray gun makes the coal powder pass through the coal powder conveying pipeline, the coal powder ring pipe and the N_xCoal dust branch pipe, N_xPulverized coal inlet and fuel outlet of individual fuel switch, and N _xAnd the spray gun flows into the kiln chamber.

22. Method according to any of claims 18-21, wherein said calculating the number of handovers N_mThe method comprises the following steps:

according to the first pressure detector and the second pressure detectorThe maximum number of gas lances N allowed in the lance group at the current gas loop pressure P1 is calculated_q；

23. The method of claim 22, wherein the maximum number of gas injection lances N is calculated according to the following formula_q：

24. A method according to any one of claims 18 to 21, wherein the total heat supply Q of the loop heating area is_iComprises the following steps:

Q₁＝Q÷ i＝1

Q_i＝Q×k_1i/ 2≤i≤Y

in the formula, Q₁The total heat supply quantity of a 1 st annular heat supply area is provided, and the 1 st annular heat supply area is positioned at the center of the section of the kiln chamber; q is the theoretical heat supply amount needed when the material is roasted under the height of a certain section of the kiln chamber; the heat transfer efficiency between the flue gas and the materials in the lime kiln is improved; k is a radical of _1iThe heating proportionality coefficient between the 1 st annular heating area and the ith annular heating area is calculated; y is the number of annular heating zones.

25. The method of claim 24, wherein the average of each lance in the annular heating zone is calculated according to the formulaUniform gas supply W_ij：

26. The method of claim 24, wherein the fuel supply T to each lance in the annular heating zone is calculated according to the formula_ij：