WO2020216289A1 - 一种石灰窑及其供热方法 - Google Patents

一种石灰窑及其供热方法 Download PDF

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Publication number
WO2020216289A1
WO2020216289A1 PCT/CN2020/086384 CN2020086384W WO2020216289A1 WO 2020216289 A1 WO2020216289 A1 WO 2020216289A1 CN 2020086384 W CN2020086384 W CN 2020086384W WO 2020216289 A1 WO2020216289 A1 WO 2020216289A1
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WIPO (PCT)
Prior art keywords
gas
pulverized coal
fuel
spray gun
kiln
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PCT/CN2020/086384
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English (en)
French (fr)
Chinese (zh)
Inventor
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
中冶长天国际工程有限责任公司
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Priority to BR112021013845-5A priority Critical patent/BR112021013845A2/pt
Publication of WO2020216289A1 publication Critical patent/WO2020216289A1/zh

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    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2/00—Lime, magnesia or dolomite
    • C04B2/10—Preheating, burning calcining or cooling
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23D—BURNERS
    • F23D17/00—Burners for combustion conjointly or alternatively of gaseous or liquid or pulverulent fuel
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D17/00—Arrangements for using waste heat; Arrangements for using, or disposing of, waste gases

Definitions

  • the lime kiln is the core equipment in the lime production process.
  • the raw material of limestone is heated to 1100°C in the lime kiln and calcined to produce finished lime.
  • the fuel used for the calcination of limestone usually includes coal gas and coal powder. Due to the different combustion characteristics of coal gas and pulverized coal, the type of fuel used for a particular lime kiln is generally fixed.
  • Limestone raw materials are loaded from the top of the kiln 1, the fuel is distributed from the fuel ring 2'to each spray gun 31, and each spray gun 31 evenly distributes the fuel to the inside of the kiln 1, while delivering combustion-supporting air to the inside of the kiln 1.
  • the limestone raw material is calcined and decomposed to produce 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 1 and the finished calcium oxide is cooled to the preset temperature under the action of the cooling air at the bottom of the kiln 1 The discharge temperature is then discharged from the bottom of the kiln 1 to complete the production of quicklime.
  • this application provides a lime kiln, including a kiln, a heating device, and a combustion-supporting fan.
  • a combustion-supporting air pipe is connected between the combustion-supporting fan and the kiln.
  • the combustion-supporting air pipe is provided with a combustion-supporting air cutoff valve and the heating device Including fuel supply device and spray gun group, the spray gun group is connected with the inside of the kiln.
  • the spray gun group has a total of N spray guns.
  • the fuel supply device includes a gas supply device and a pulverized coal supply device.
  • the gas supply device includes a gas ring pipe and N gas
  • the pulverized coal supply device includes a pulverized coal ring pipe and N pulverized coal branch pipes connected with the pulverized coal ring pipe, and each pulverized coal branch pipe is connected with The inlet end of a spray gun is connected so that the gas supply device and the pulverized coal supply device share the spray gun group;
  • each gas branch pipe is provided with a gas branch pipe regulating valve, and each coal branch pipe is provided with a coal powder branch pipe regulating valve; on the spray gun
  • a flow detector is provided; a first calorific value detector and a first pressure detector are respectively set on the gas loop pipe, a second calorific value detector is set on the coal powder loop pipe, and a second pressure detector is set inside the kiln;
  • the bore section is divided into a number of annular heating areas in the radial direction.
  • the gas conveying fan and the gas ring pipe are connected through the gas conveying pipe, and the gas conveying pipe is equipped with a gas shut-off valve;
  • the pulverized coal supply device also includes the pulverized coal conveying fan, the pulverized coal conveying fan and the pulverized coal ring pipe
  • the pulverized coal transportation pipeline is connected, and the pulverized coal transportation pipeline is provided with a pulverized coal shut-off valve.
  • the fuel supply device further includes a nitrogen purging device, and the nitrogen purging device includes a nitrogen compression tank and a nitrogen loop,
  • the nitrogen ring pipe is connected with N nitrogen branch pipes, and the N nitrogen branch pipes are respectively provided with nitrogen branch pipe regulating valves, the nitrogen compression tank and the nitrogen ring pipe are connected through a nitrogen delivery pipeline, and the nitrogen delivery pipeline is provided with a nitrogen shut-off valve;
  • the device also includes a nitrogen inlet.
  • the nitrogen inlet is connected to the nitrogen branch pipe. There is a valve body at the nitrogen inlet.
  • each valve body By adjusting each valve body, only one of the gas inlet, the pulverized coal inlet and the nitrogen inlet is connected to the fuel outlet at the same time; When the nitrogen shut-off valve and the valve body at the nitrogen inlet are used, the residual gas or coal powder in the fuel switch is blown into the spray gun by nitrogen.
  • the valve body includes a rigid sealing ring, a sealing plug, and a return spring;
  • this application provides a method for heating a lime kiln, which is used in the lime kiln as described in the first aspect or the first possible implementation of the first aspect, and the method includes:
  • Heating area average calculation annular gas supply quantity W ij of each gun adjust the opening of each of the gas branch pipe control valve, the measuring flow detector and the value S ij W ij match;
  • N m is the theoretical number of spray guns that need to switch the fuel medium
  • N x is the actual number of spray guns that need to switch the fuel medium.
  • the calculating the number of switching N m includes:
  • [rho] is the gas density
  • v i is the lance gas design flow rate
  • h i is the coefficient of drag gas manifold
  • P 1 is the gas loop first pressure detector measurement
  • P 2 is the internal pressure of the kiln measured by the second pressure detector
  • ⁇ is the correction coefficient related to the particle size of the limestone particles in the kiln.
  • the method further includes:
  • a number of uniform heating modes are preset; the uniform heating mode is used to indicate that N m is in the specified value range In the spray gun group, the spray gun position of the fuel medium and the actual spray gun number N x in the spray gun group need to be switched.
  • the method further includes:
  • the fuel medium of the N x spray guns in the corresponding part is switched from coal gas to pulverized coal.
  • the method further includes:
  • the corresponding relationship between the value range of N m and the spray gun set is established to obtain a uniform heating mode; the spray gun set includes the labels of N x spray guns in the spray gun group that need to switch the fuel medium.
  • the method further includes:
  • the uniform heating threshold N y is determined ;
  • N x is equal to N, so that the uniform heating mode is a single pulverized coal heating
  • N x is equal to 0, so that the uniform heating mode is single gas heating.
  • the total amount of heat for heating the annular region Q i is:
  • Q 1 is the total heat supply of the first annular heating area, which is located at the center of the kiln bore; Q is when the material is roasted at a certain height of the kiln bore The required theoretical heat supply; ⁇ is the heat transfer efficiency between the flue gas and the material in the lime kiln; k 1i is the heat supply ratio coefficient between the first annular heating area and the i-th annular heating area; Y is the number of circular heating areas.
  • the average gas supply amount W ij of each spray gun in the annular heating area is calculated according to the following formula:
  • the unit calorific value of coal gas measured by the detector, h 2 is the unit calorific value of pulverized coal measured by the second calorific value detector, 1 ⁇ j ⁇ X i , 1 ⁇ i ⁇ Y.
  • the fuel supply device includes a gas supply device and a pulverized coal supply device, and the independent gas supply device and the pulverized coal supply device share a spray gun group, and each spray gun in the spray gun group is connected to a gas branch pipe. And the pulverized coal branch pipe, so that the fuel medium delivered by each spray gun can be switched between coal gas and pulverized coal.
  • the first pressure detector is used to measure the pressure of the gas loop
  • the second pressure detector is used to measure the internal pressure of the kiln. When the pressure difference between the two is greater than or equal to the minimum inlet pressure, it indicates that the gas supply is sufficient.
  • the single gas heating is preferred, and the average gas supply Wij of each spray gun in the annular heating area is calculated, and the opening of each gas branch control valve is adjusted to match the measured value S ij with Wij of the flow detector. In order to ensure the uniformity and accuracy of heat supply in the kiln section.
  • the pressure difference between the first pressure detector and the second pressure detector is less than the minimum inlet pressure, it indicates that the gas pressure fluctuates, causing the pressure of the gas pipeline network to be too low, and the gas pressure is not enough to support the kiln inlet.
  • this application can ensure the stable operation of the lime kiln under low gas pressure conditions, ensure that the fuel medium supply in the kiln is sufficient, and the fuel medium of the lime kiln can be switched instead of being single. Thereby improving the production stability and production adaptability of the lime kiln, which is conducive to the continuous and efficient production of the lime kiln.
  • the present application provides a heating method for a lime kiln, which is used in the lime kiln as described in the sixth possible implementation manner of the first aspect, and the method includes:
  • the single gas heating mode When the pressure difference between the first pressure detector and the second pressure detector is greater than or equal to the minimum kiln inlet pressure, the single gas heating mode is activated, so that all N spray guns deliver gas fuel to the kiln; the single gas heating mode It is: the valve body at the gas inlet of the gas shut-off valve, the gas conveying fan and the N fuel switchers are all open, and the valve body at the pulverized coal inlet of the pulverized coal shutoff valve and the N fuel switchers are all closed.
  • the pulverized coal conveying fan is in standby state, the nitrogen shut-off valve and the valve bodies at the nitrogen inlet of the N fuel switchers are all closed; the gas return valve is closed, and the pulverized coal return valve is open; N gas branch control valves , N pulverized coal branch control valves and N nitrogen branch control valves are all open;
  • Heating area average calculation annular gas supply quantity W ij of each gun adjust the opening of each of the gas branch pipe control valve, the measuring flow detector and the value S ij W ij match;
  • N m is the theoretical number of spray guns that need to switch the fuel medium
  • the uniform heating mode is used to indicate when N m is within the specified value range, the position of the spray gun in the spray gun group that needs to switch the fuel medium and the actual number of spray guns N x , N m ⁇ N x ⁇ N;
  • the method further includes:
  • N x is equal to N, so that the uniform heating mode is a single pulverized coal heating
  • N x is equal to 0, so that the uniform heating mode is single gas heating.
  • the uniform heating mode when the uniform heating mode is a single pulverized coal heating, the uniform heating mode is activated as follows:
  • Nitrogen shut-off valve Opens the nitrogen shut-off valve and the valve body at the nitrogen inlet of the N fuel switchers in sequence. After the nitrogen blows the residual coal powder inside the fuel switcher to the spray gun, close the valve body and the valve body at the nitrogen inlet of the N fuel switchers in turn. Nitrogen shut-off valve;
  • the uniform heating mode when the uniform heating mode is combined heating of coal gas and pulverized coal, the uniform heating mode is activated as follows:
  • valve body allows the pulverized coal to flow into the kiln chamber through the pulverized coal conveying pipeline, the pulverized coal ring pipe, N x pulverized coal branch pipes, N x pulverized coal inlets and fuel outlets of the fuel switcher, and N x spray guns in sequence .
  • the calculating the number of switching N m includes:
  • the maximum number of gas spray guns N q is calculated according to the following formula:
  • [rho] is the gas density
  • v i is the lance gas design flow rate
  • h i is the coefficient of drag gas manifold
  • P 1 is the gas loop first pressure detector measurement
  • P 2 is the internal pressure of the kiln measured by the second pressure detector
  • ⁇ is the correction coefficient related to the particle size of the limestone particles in the kiln.
  • the total amount of heat for heating the annular region Q i is:
  • Q 1 is the total heat supply of the first annular heating area, which is located at the center of the kiln bore; Q is when the material is roasted at a certain height of the kiln bore The required theoretical heat supply; ⁇ is the heat transfer efficiency between the flue gas and the material in the lime kiln; k 1i is the heat supply ratio coefficient between the first annular heating area and the i-th annular heating area; Y is the number of circular heating areas.
  • the average gas supply amount W ij of each spray gun in the annular heating area is calculated according to the following formula:
  • Q i is the total amount of heat for heating the annular region
  • X i is the number of guns in the annular heating zone comprises
  • h 1 is the gas specific heat value of the first heating value detector is measured
  • the fuel supply amount T ij of each spray gun in the annular heating area is calculated according to the following formula:
  • the gas supply device and the pulverized coal supply device are used in parallel, and the lime kiln fuel switching control is realized through the fuel switch.
  • the first pressure detector is used to measure the pressure of the gas loop
  • the second pressure detector is used to measure the internal pressure of the kiln.
  • the single gas heating mode is preferred, and the average gas supply amount Wij of each spray gun in the annular heating area is calculated, and the opening of each gas branch pipe regulating valve is adjusted to match the measured value S ij of the flow detector with Wij , In order to ensure the uniformity and accuracy of heat supply in the kiln section.
  • the uniform heating mode is based on the uniformity of heating to the chamber, according to the total number N of spray guns included in the spray gun group, and each spray gun distribution in the furnace chamber section is set in advance, as long as N m is calculated, to find the relevant parts of the gun N m ranges corresponding need to switch connected to the fuel, and the actual number of spray guns N x.
  • the gas inlet, the pulverized coal inlet and the nitrogen inlet inside the fuel switch are respectively provided with valve bodies, and only one valve body at the inlet is opened at the same time, and the remaining valve bodies are closed, so as to avoid the interconnection between the inlets.
  • the pulverized coal supply device and the gas supply device are combined and isolated through the fuel switcher. By controlling the opening and closing status of each valve in the lime kiln and the operation status of the fan, the lime kiln fuel medium can be quickly, automatically and flexibly switched. Realize diversified heating modes, thus overcoming the shortcomings of the single type of heating fuel of the lime kiln and poor production adaptability.
  • this scheme divides the cross section of the lime kiln into several heating areas along the radial direction, and according to each heating area The amount of heat dissipation is different, and the total heat supply required by each heating area is obtained, so as to accurately calculate and implement the fuel supply required by each independent spray gun, so as to achieve precise heating and make the kiln bore different positions on the same horizontal section
  • the materials at the location are heated uniformly, avoiding over-burning or raw burning of lime, thereby improving the quality of the lime kiln product. Therefore, the application can significantly improve the performance of the lime kiln.
  • Figure 1 is a schematic diagram of the structure of an existing lime kiln
  • Example 2 is a schematic diagram of the overall structure of the lime kiln shown in Example 1 of this application;
  • Figure 3 is a structural diagram of the heating device of the lime kiln shown in the first embodiment of the application;
  • Figure 4 is a division diagram of the annular heating area on the kiln bore section shown in Example 1 of the application;
  • Figure 5 is a distribution diagram of each spray gun in the kiln bore cross section in the spray gun group shown in Example 1 of the application;
  • FIG. 6 is a distribution diagram of gas spray guns and pulverized coal spray guns in each uniform heating mode shown in Embodiment 1 of the application;
  • Figure 7 is a schematic diagram of the overall structure of the lime kiln shown in the third embodiment of the application.
  • FIG. 8 is a schematic diagram of a partial structure of a lime kiln shown in Example 3 of this application.
  • FIG. 9 is a schematic structural diagram of a fuel switch shown in the third embodiment of the application.
  • FIG. 10 is a schematic structural diagram of another fuel switch shown in the third embodiment of the application.
  • FIG. 11 is a schematic diagram of the structure of the spray gun body shown in the fifth embodiment of the application.
  • FIG. 12 is a circular cross-sectional view of a section of the spray gun body close to the outlet shown in the fifth embodiment of the application;
  • FIG. 13 is a schematic diagram of the spreading range of the spray gun shown in Embodiment 5 of the application.
  • the first embodiment of the present application provides a lime kiln, including a kiln 1, a heating device and a combustion-supporting fan 2.
  • the heating device is used to supply and transport calcined limestone into the kiln 1.
  • the combustion-supporting air pipe 21 is connected between the combustion-supporting fan 2 and the kiln 1, and the combustion-supporting air pipe 21 is provided with a combustion-supporting air shut-off valve 22. When the combustion-supporting fan 2 is started and the combustion-supporting air shut-off valve 22 is opened, the combustion-supporting air will be The combustion-supporting air pipe 21 enters the interior of the kiln 1 to provide combustion-supporting air for fuel combustion and heat release.
  • the heating device includes a fuel supply device and a spray gun group 3.
  • the spray gun group 3 communicates with the inside of the kiln 1, and the spray gun group 3 is used to deliver the fuel provided by the fuel supply device to the inside of the kiln 1.
  • the spray gun group 3 has N spray guns 31 in total, that is, the total number of spray guns 31 in the spray gun group 3 is N.
  • the fuel supply device includes a gas supply device 4 and a pulverized coal supply device 5.
  • the gas supply device 4 includes a gas ring pipe 401 and N gas branch pipes 402 connected with the gas ring pipe 401, and each gas branch pipe 402 is connected to a spray gun 31.
  • the pulverized coal supply device 5 includes a pulverized coal ring pipe 501 and N pulverized coal branch pipes 502 connected to the pulverized coal ring pipe 501.
  • Each pulverized coal branch pipe 502 is connected to the inlet end of a spray gun 31 to make the gas
  • the supply device 4 and the pulverized coal supply device 5 share the spray gun group 3;
  • each gas branch pipe 402 is provided with a gas branch pipe regulating valve 403, and each coal powder branch pipe 502 is provided with a coal powder branch pipe regulating valve 503;
  • the spray gun 31 is provided with a flow rate Detector 311;
  • a first calorific value detector 404 and a first pressure detector 405 are set on the gas loop 401, a second calorific value detector 504 is set on the pulverized coal loop 501, and a second pressure is set in the kiln 1 Detector 11.
  • the existing lime kiln can only use one of gas or pulverized coal fuel, if the fuel type needs to be changed, the heating system of the lime kiln can only be modified, which is very inflexible.
  • coal gas is a by-product of ironmaking and steelmaking processes. Although the cost is low, the supply is not stable. The gas volume and calorific value of coal gas often fluctuate greatly. Only coal gas is used as a single fuel. It is difficult to guarantee the stability of production, and the use of pulverized coal as a single fuel will increase the cost of lime production. It can be seen that the existing lime kiln has a single heating fuel and cannot adapt and flexibly switch the fuel type according to the working conditions in the steel plant, resulting in poor production adaptability and low lime kiln performance.
  • the heating device includes parallel gas supply devices and pulverized coal supply devices, independent gas supply devices and pulverized coal supply devices sharing spray gun group 3, gas branch pipes 402.
  • the number of pulverized coal branch pipes 502 and the spray guns 31 included in the spray gun group 3 are equal, and both are N.
  • each spray gun 31 in the spray gun group 3 is connected to a gas branch pipe 402 and a pulverized coal branch pipe 502, and a single spray gun 31 corresponds to
  • the gas branch pipe regulating valve 403 and the pulverized coal branch pipe regulating valve 503 are not opened at the same time to prevent the gas branch pipe 402 from communicating with the pulverized coal branch pipe 502, so as to ensure that each spray gun 31 does not spray mixed fuel of gas and coal.
  • the fuel medium delivered by the spray gun 31 is coal gas.
  • the fuel medium delivered by the spray gun 31 is pulverized coal.
  • the fuel medium delivered by each spray gun 31 can be quickly controlled to switch between coal gas and pulverized coal, thereby effectively solving the problem.
  • the existing lime kiln has a single fuel and the problem of flexible switching of the fuel medium according to the production conditions of the lime kiln, thereby improving the production adaptability of the lime kiln.
  • coal gas fuel as a by-product of ironmaking and steelmaking processes, has the advantages of low cost and simple combustion device. Therefore, this application uses coal gas fuel as the initial heating of the lime kiln when the gas pressure meets the conditions for entering the kiln.
  • the first pressure detector 405 is used to measure the gas ring pressure P 1
  • the second pressure detector 11 is used to measure the internal pressure P 2 of the kiln.
  • the pressure difference ⁇ P between the two is greater than or equal to the minimum inlet pressure
  • ⁇ P min is sufficient, it means that the gas supply is sufficient to meet the conditions for entering the kiln.
  • the single gas heating is preferred.
  • the least, the theoretically required heat supply is also the least; and the heat dissipation perimeter at the edge of the kiln bore is the largest, and the heat dissipation is the largest, so the theoretical heat supply is also the largest. Due to the constraints of the above two factors, even if the spray guns 31 in the spray gun group 3 are evenly distributed along the cross section of the kiln 1, they cannot truly provide accurate and uniform heating for the lime kiln.
  • the section of the kiln 1 in this embodiment is divided into a number of annular heating areas in the radial direction.
  • it is divided into four annular heating areas from the inside to the outside, which are R1, R2, R3 and R4, where R1 is located at the center of the section of the kiln 1 and R4 is located at the edge of the section of the kiln 1.
  • the spray gun group 3 includes several spray gun matrices, and each spray gun matrix is correspondingly arranged in an annular heating area
  • Each spray gun matrix includes a number of spray guns 31 evenly distributed along the circumference.
  • the spray gun matrix of the annular heating area R1 includes one spray gun 31, and the spray gun matrix of the annular heating area R2 includes 8 spray guns 31.
  • Each spray gun 31 in the spray gun group 3 can be labeled in advance, for example, the label format is qij, i is the serial number used to characterize the annular heating area, and j is the spray gun sequence number used to characterize the spray gun matrix in the area, such as the number in R2
  • the spray gun of q23 is used to identify the third spray gun in the second annular heating area (R2), so as to facilitate the precise identification and control of each spray gun 31.
  • the total heat supply of the ring heating area R2 is Q 2
  • the first calorific value detector 404 is used to measure the unit calorific value h 1 of coal gas
  • the second calorific value detector 504 is used to measure the unit calorific value h 2 of coal powder
  • the spray gun numbered q23 is transported
  • the present application can accurately obtain the fuel supply required by each spray gun 31 according to the difference in heat dissipation of each annular heating area, so as to achieve accurate and uniform heating of the lime kiln, thereby improving the performance of the lime kiln.
  • the lime kiln described in the embodiment may further include a computer control unit configured to execute the program steps described in the second embodiment below.
  • the second embodiment of the present application specifically provides a lime kiln heating method, which is used in the lime kiln as described in the first embodiment, and the method includes the following program steps:
  • Step S101 when the pressure difference between the first pressure detector and the second pressure detector is greater than or equal to the minimum kiln inlet pressure, close N pulverized coal branch control valves, open N gas branch control valves, and make all N spray guns face The kiln conveys gas fuel.
  • the single-gas heating mode is: N All pulverized coal branch pipe regulating valves 503 are in a closed state, and N coal gas branch pipe regulating valves 403 are all in an open state.
  • Step S102 Calculate the average gas supply amount Wij of each spray gun in the annular heating area, adjust the opening degree of each gas branch pipe regulating valve, and match the measured value S ij of the flow detector with Wij .
  • Q i is the total amount of heat for heating the annular region
  • X i is the number of guns in the annular heating zone comprises
  • h 1 is the gas specific heat value of the first heating value detector is measured
  • Y is the number of annular heating areas.
  • Q 1 is the total heat supply of the first annular heating area, which is located at the center of the kiln bore; Q is when the material is roasted at a certain height of the kiln bore The required theoretical heat supply; ⁇ is the heat transfer efficiency between the flue gas and the material in the lime kiln; k 1i is the heat supply ratio coefficient between the first annular heating area and the i-th annular heating area. Since the first annular heating zone (i.e., R1) is located at a center of the bore cross-sectional kiln, the minimum amount of heat, so it is preferably used as a reference area, to calculate the total amount of heat for heating the other annular areas Q i, i is greater than 1.
  • k 12 is the heat supply ratio coefficient between R1-R2. Because R1 and R2 have different positions on the kiln section and the heat dissipation capacity, the total heat supply required by the two is different, k 12 It is the scale factor used to characterize these differences, and its value range is 1.15-1.3;
  • k 13 is the heat supply ratio coefficient between R1-R3. Because R1 and R3 have different positions on the kiln bore section and the heat dissipation, the total heat supply required by the two is different. K 13 is used To characterize these differentiated scale coefficients, the value range is 1.3-1.5;
  • k 14 is the heat supply ratio coefficient between R1-R4. Because R1 and R4 have different positions on the kiln bore section and different heat dissipation capacity, the total heat supply required by the two is different. K 14 is used To characterize these differentiated scale coefficients, the value range is 1.5-1.75.
  • each lance may be in the sync area 31 corresponding to the opening degree of the gas valve manifold 403, each lance the flow measuring instrument of measurement values S ij 31 Matching with Wij , the precise heating regulation under the single gas heating mode is completed.
  • the division method of the annular heating area is not limited to this embodiment and shown in Figure 4, so k 1i can be selected according to the specific area division method, and in other possible implementation manners, the kiln can also be The corresponding annular heating area at the middle section or edge of the cross-section is used as the reference area to obtain the differentiated scale factor between the reference area and other annular heating areas.
  • Step S103 when the pressure difference is less than the minimum kiln inlet pressure, calculate the switching number N m ; N m is the theoretical number of spray guns that need to switch the fuel medium.
  • the single gas heating mode After the single gas heating mode is activated, it is still necessary to check whether the pressure difference ⁇ P is greater than or equal to the minimum kiln inlet pressure ⁇ P min in real time. If it is, the gas pressure meets the kiln inlet conditions and maintain the current single gas heating state; ⁇ P is less than the minimum kiln inlet pressure ⁇ P min , indicating that the pressure of the gas pipe network is insufficient to support the kiln inlet, and part or all of the fuel medium of the spray gun 31 needs to be switched from coal gas to coal powder.
  • the maximum number of gas spray guns N q allowed in the spray gun group 3 under the current gas loop pressure P 1 can be calculated, and the spray gun group 3 includes
  • ⁇ is the gas density
  • v t is the gas loop of gas flow rate
  • h i is the coefficient of drag gas manifold.
  • each spray gun 31 Since the geometric dimensions and other conditions of each spray gun 31 are the same, the gas flow rate of each spray gun 31 is the same, and the gas flow rate v t in the gas loop can be calculated according to the following formula (b):
  • the spray gun 31 of the lime kiln is generally set in the buried limestone layer, and the fuel burns directly inside the layer. This causes the fuel to be sprayed from the spray gun 31, not only Need to overcome the pipe resistance, but also need to overcome the additional layer resistance.
  • the resistance of the material layer to the fuel is related to the particle size and porosity of the material under the spray gun 31.
  • the material at the spray gun 31 is a mixture of limestone raw materials and calcium oxide powder, and it is difficult to accurately calculate the corresponding resistance.
  • the correction coefficient ⁇ is related to the particle size of the limestone material particles, and the specific value of the correction coefficient ⁇ can be referred to Table 1 below.
  • Average particle size of limestone ⁇ 30mm 30mm-40mm 40mm-60mm >60mm
  • Correction factor ⁇ 0.4 0.6 0.75 0.8
  • N q can only be an integer, and in order to ensure that the gas flow rate of the spray gun is not lower than the design requirement, the N q calculated by formula (e) is rounded down to obtain formula (f):
  • Step S104 close N x gas branch control valves, correspondingly open N x pulverized coal branch control valves, so that the fuel delivered by N x spray guns in the spray gun group is switched from gas to pulverized coal, and N x is the actual fuel medium that needs to be switched Number of spray guns, N m ⁇ N x ⁇ N.
  • N x pulverized coal branch pipe regulating valves 503 in the pulverized coal supply device where N x is greater than or equal to N m , so that there are at least N m spray guns 31 in the spray gun group 3 whose fuel medium is switched from the original gas to coal
  • N x is greater than or equal to N m
  • the gas in the other NN x spray guns 31 in the spray gun group 3 can be sprayed into the kiln 1 at a flow rate not lower than the design requirement, so that the fuel medium of the designated spray gun 31 can be automatically switched according to the gas pressure.
  • this application can ensure the stable operation of the lime kiln under the condition of low gas pressure and ensure sufficient fuel medium supply in the kiln, thereby improving the production stability and production adaptability of the lime kiln. Conducive to the continuous and efficient production of the lime kiln, thereby improving the performance of the lime kiln.
  • the method further includes: presetting several uniform heating modes according to the total number N of spray guns included in the spray gun group 3 and the distribution state of each spray gun 31 on the cross section of the kiln 1;
  • the uniform heating mode is used to indicate that when N m is within a specified value range, the spray gun positions in the spray gun group 3 where the fuel medium needs to be switched and the actual number of spray guns N x .
  • Determine the target uniform heating mode corresponding to the value range of N m and then switch the fuel medium of the N x spray guns in the corresponding position from coal gas to pulverized coal according to the instruction of the target uniform heating mode.
  • uniform heating threshold N y can be determined according to the total number N and the distribution state of each of the gun on the gun bore section of the kiln and other information, when N m When it is greater than N y , if the combined heating with coal gas and pulverized coal is used, the uniformity of temperature distribution in the kiln cannot be guaranteed.
  • N x is equal to N, so that the uniform heating mode is a single pulverized coal heating
  • the uniform heating mode is gas and pulverized coal combined heating
  • N x is equal to 0, so that the uniform heating mode is single gas heating.
  • Fig. 5 is an example of the thirty-three spray guns 31 in the spray gun group 3.
  • the spray gun matrixes are respectively set in the four annular heating regions.
  • the spray gun matrix in the first annular heating region R1 includes one spray gun 31, and the second
  • the spray gun matrix in the ring heating area R2 includes eight spray guns 31,
  • the third ring heating area R3 includes eight spray guns 31,
  • the fourth ring heating area R4 includes sixteen spray guns 31.
  • This structure can make the thirty-three spray guns evenly distributed on the cross section of the kiln 1, thereby facilitating the even distribution of the kiln temperature.
  • this embodiment shows seven uniform heating modes, as shown in the following table 2.
  • the uniform heating threshold N y corresponding to this spray gun group structure is equal to 9, and the uniform heating mode 1 is single Gas heating mode, uniform heating mode 2-6 is the combined heating mode of gas and pulverized coal, and uniform heating mode 7 is the single pulverized coal heating mode.
  • N m 1
  • N x 1
  • the pulverized coal spray gun is a spray gun at the center of the first annular heating area (that is, the spray gun location where the fuel medium needs to be switched).
  • N m 5
  • N x 5
  • 4 pulverized coal spray guns are distributed in the spray gun matrix of the third annular heating area at intervals, and the other pulverized coal spray gun is the spray gun in the center of the first annular heating area.
  • this embodiment and Figure 6 show the optional uniform heating mode when 33 spray guns are distributed according to Figure 5.
  • the uniform heating threshold can be determined adaptively according to the actual situation. As well as setting the corresponding uniform heating mode, this application does not limit this.
  • the method further includes: pre-labeling each spray gun in the spray gun group; establishing a correspondence between the value range of N m and the spray gun set , A uniform heating mode is obtained, and the spray gun set includes the numbers of the N x spray guns in the spray gun group that need to switch the fuel medium.
  • each spray gun can be labeled in sequence according to the distribution of the spray gun matrix.
  • the number of the spray gun matrix in the first circular heating area is q11, and the spray guns in the second circular heating area are labeled clockwise in turn They are q21 ⁇ q28, the spray guns in the third ring heating zone are numbered q31 ⁇ q38 in turn clockwise, and the spray guns in the fourth ring heating zone are numbered q41 ⁇ q416 in turn clockwise.
  • the uniform heating mode can be expressed as:
  • the uniform heating mode 3 is the corresponding relationship between 1 ⁇ N m ⁇ 4 and ⁇ q21, q23, q25, q27 ⁇ ;
  • Uniform heating mode 5 is the corresponding relationship between 5 ⁇ N m ⁇ 8 and ⁇ q21, q22, q23, q24, q25, q26, q27, q28 ⁇ ;
  • the uniform heating mode 7 is the corresponding relationship between 9 ⁇ N m ⁇ 33 and ⁇ full set ⁇ .
  • the gas branch control valve 403 corresponding to the q27 spray gun is closed, and the coal powder branch control valve 503 corresponding to the q21, q23, q25, and q27 spray guns in the spray gun group 3 is opened, so that the spray guns labeled q21, q23, q25, q27
  • the fuel medium is switched from coal gas to pulverized coal, and the spray gun corresponding to the label not included in the spray gun set ⁇ q21, q23, q25, q27 ⁇ still keeps delivering gas fuel.
  • Step S105 Calculate the fuel supply T ij of each spray gun in the annular heating area, and adjust the opening of the N x pulverized coal branch control valves and the other NN x gas branch control valves to make the measured value of the flow detector S ij matches T ij .
  • step S102 Calculated in step S102 with reference to the total amount of heat for heating the respective annular regions illustrated Q i, and on this basis, according to the following formula to calculate the heating zone an annular fuel supply amount for each gun T ij, where the The fuel is gas or pulverized coal:
  • the unit calorific value of coal gas measured by the detector, h 2 is the unit calorific value of pulverized coal measured by the second calorific value detector, 1 ⁇ j ⁇ X i , 1 ⁇ i ⁇ Y.
  • the fuel supply volume T ij of the five spray guns (numbered q11, q31, q33, q35, q37) in the corresponding part, that is, the pulverized coal supply volume, the fuel supply volume of the q11 spray gun is T 11 , then adjust q11
  • the opening degree of the pulverized coal branch pipe regulating valve 503 corresponding to the spray gun matches the measured value S 11 of the flow detector of the q11 spray gun with T 11 , and similarly adjusts the pulverized coal flow of the q31, q33, q35 and q37 spray guns.
  • the fuel supply is calculated as T 32 , That is the gas supply, adjust the opening of the gas branch control valve 403 corresponding to the q32 spray gun to match the measured value S 32 of the flow detector of the q32 spray gun with T 32 , and adjust the other NN x -1 spray guns in the same way. Gas flow, so that the entire spray gun group 3 provides precise heating for the kiln 1.
  • Step S106 Open the combustion-supporting air shut-off valve, increase the operating frequency of the combustion-supporting fan, and make the combustion-supporting air volume into the kiln match the total amount of fuel, and the switching process ends.
  • this application can ensure the stable operation of the lime kiln under low gas pressure conditions, ensure that the fuel medium supply in the kiln is sufficient, and the fuel medium of the lime kiln can be switched without It is single again to improve the production stability and production adaptability of the lime kiln, which is conducive to the continuous and efficient production of the lime kiln.
  • this scheme divides the cross section of the lime kiln into several heating areas along the radial direction, and dissipates heat according to each heating area Obtain the total heat supply required by each heating area, so as to accurately calculate and implement the fuel supply required by each independent spray gun, so as to achieve precise heat supply and make the kiln at different positions on the same horizontal section
  • the materials are heated uniformly to avoid over-burning or raw burning of lime, thereby improving the quality of the lime kiln product. Therefore, this solution can significantly improve the performance of the lime kiln.
  • the third embodiment of the present application provides another lime kiln.
  • the fuel supply device further includes N fuel switchers 6, and the fuel switch The device 6 corresponds to the spray gun 31 one-to-one.
  • Figures 7-9 only show the connection structure of one set of fuel switch 6 and spray gun 31.
  • the connection structure of the other N-1 groups of fuel switch 6 and spray gun 31 is the same. Therefore, it is not shown in the figure.
  • the fuel switch 6 is used to combine and isolate the gas supply device 4 and the pulverized coal supply device 5 to ensure that the lime kiln can switch fuel from coal gas to pulverized coal, and fuel from pulverized coal to gas, and ensure There will be no mixed flow between coal gas and pulverized coal in the lime kiln.
  • Limestone raw materials are loaded into the kiln 1 through the distributor 8.
  • the spray gun 31 is used to spray the switched fuel (gas or coal) into the kiln 1, and then open the combustion air shut-off valve 22 to enable the combustion fan 2 to deliver
  • the combustion-supporting air enters the kiln 1 through the combustion-supporting air pipe 21, and the fuel is burned to provide heat for the calcined limestone to produce lime products.
  • Each fuel switch 6 includes a gas inlet 61, a pulverized coal inlet 62 and a fuel outlet 64.
  • the gas inlet 61 is connected to the gas branch pipe 402, the pulverized coal inlet 62 is connected to the pulverized coal branch pipe 502, and the fuel outlet 64 is connected to the inlet of the spray gun 31.
  • the gas inlet 61 and the pulverized coal inlet 62 are respectively provided with valve bodies 65; the gas supply device 4 also includes a gas conveying fan 406.
  • the gas conveying fan 406 and the gas ring pipe 401 are connected through the gas conveying pipe 407, and the gas conveying pipe 407 There is a gas shut-off valve 408; the pulverized coal supply device 5 also includes a pulverized coal conveying fan 505.
  • the pulverized coal conveying fan 505 is connected to the pulverized coal ring pipe 501 through a pulverized coal conveying pipe 506.
  • the pulverized coal conveying pipe 506 is provided with pulverized coal. Shut off valve 507.
  • the gas conveying fan 406, the gas conveying pipe 407, and the gas ring pipe 401 constitute the main gas pipeline.
  • N gas branches are generated from the gas ring pipe 401, and the gas branches include corresponding gas in turn.
  • the pulverized coal conveying fan 505, the pulverized coal conveying pipe 506, and the pulverized coal ring pipe 501 constitute the pulverized coal main pipeline, and N pulverized coal branch roads are generated from the pulverized coal ring pipe 501.
  • the pulverized coal branch road includes a pulverized coal branch pipe 502, a fuel switch 6 and a spray gun 31 corresponding in sequence.
  • the pulverized coal shut-off valve 507 When the pulverized coal shut-off valve 507 is in the open state and the pulverized coal conveying fan 505 is working normally, the main pulverized coal pipeline is turned on, and the N pulverized coal branch circuits are also turned on, thus transporting pulverized coal fuel to the kiln 1; The pulverized coal shut-off valve 507 is in the closed state, and when the operation frequency of the pulverized coal conveying fan 505 is low to the standby state, the entire pulverized coal supply pipeline is cut off, and at this time, no pulverized coal is supplied to the kiln 1.
  • the valve body 65 at the pulverized coal inlet 62 is opened, and the valve body 65 at the gas inlet 61 is closed to avoid coal.
  • the pulverized coal fuel from the pulverized branch pipe 502 enters the gas supply pipeline through the gas inlet 61, thereby avoiding the mixed flow of pulverized coal and gas.
  • only the pulverized coal inlet 62 is connected to the fuel outlet 64, and the pulverized coal flows in from the pulverized coal inlet 62, flows out from the fuel outlet 64, and enters the spray gun 31.
  • valve body 65 may be a solenoid valve or a fluid control valve with other types of structures, which is not limited in this application.
  • the cross-sectional area of the fuel switch 6 is larger than the diameter of the respective inlets (the gas inlet 61, the pulverized coal inlet 62, and the nitrogen inlet 63), a small part of the fuel may not be fully discharged from the fuel outlet 64, which may result in the fuel switch 6 Fuel residue.
  • the fuel outlet 64, the spray gun 31 and the kiln 1 are in communication with each other, it may also happen that the fuel in the kiln 1 flows back to the fuel switch 6.
  • the lime kiln fuel needs to be switched from coal gas to pulverized coal
  • the valve body 65 at the pulverized coal inlet 62 is opened, the residual gas may flow from the pulverized coal inlet 62.
  • the gas and pulverized coal are not effectively isolated and cut off.
  • the fuel supply device further includes a nitrogen purging device 7, which includes a nitrogen compression tank 71 and a nitrogen ring 72, and the nitrogen ring 72 is connected with N nitrogen
  • the branch pipes 73 and the N nitrogen branch pipes 73 are respectively provided with a nitrogen branch regulating valve 74, the nitrogen compression tank 71 and the nitrogen ring pipe 72 are connected through a nitrogen delivery pipe 75, and a nitrogen shutoff valve 76 is provided on the nitrogen delivery pipe 75; the fuel switch
  • the device 6 also includes a nitrogen inlet 63.
  • the nitrogen inlet 63 is connected to the nitrogen branch pipe 73.
  • the nitrogen inlet 63 is provided with a valve body 65.
  • each valve body 65 By adjusting each valve body 65, the gas inlet 61, the pulverized coal inlet 62 and the nitrogen inlet 63 are at the same time. Only one of them is connected to the fuel outlet 64; when the nitrogen shut-off valve 76 and the valve body 65 at the nitrogen inlet 63 are opened, the residual gas or coal powder in the fuel switch 6 is blown into the spray gun 31 by nitrogen.
  • the nitrogen compression tank 71, the nitrogen delivery pipe 75 and the nitrogen loop 72 constitute a nitrogen main pipeline.
  • N nitrogen branches are generated from the nitrogen loop 72, and the nitrogen branches include corresponding nitrogen in sequence.
  • the nitrogen shut-off valve 76 When the nitrogen shut-off valve 76 is in the open state, the nitrogen main pipeline is turned on, and the N nitrogen branches are also turned on.
  • the valve body 65 at the nitrogen inlet 63 in the N fuel switches 6 is opened, and the nitrogen switches the fuel switch 6
  • the remaining fuel inside is purged into the spray gun 31 and returned to the kiln 1 by the spray gun 31; after purging, the nitrogen shut-off valve 76 and the valve body 65 at the nitrogen inlet 63 are closed, and the entire nitrogen supply pipeline is cut off.
  • the preliminary work of the switching process is completed, and the fuel can be switched based on the aforementioned gas supply pipeline or pulverized coal supply pipeline. Since nitrogen is an inert gas and is not flammable, the use of nitrogen to blow the fuel into the kiln 1 will not affect the combustion of the fuel and also avoid the risk of explosion. By installing a nitrogen purge device 7, the coal The powder and gas are effectively separated, and the safety of lime kiln production is improved.
  • this embodiment also provides a specific structure of a valve body 65.
  • the valve body 65 includes a rigid sealing ring 651, a sealing plug 652 and The return spring 653; the inner center of the fuel switch 6 is provided with a fixed support steel body 66; the rigid sealing ring 651 is fixed on the periphery of the nozzles of the gas inlet 61, the pulverized coal inlet 62 and the nitrogen inlet 63 respectively; one end of the return spring 653 and the support The steel body 66 is connected, and the other end is connected with the sealing plug 652; when the sealing plug 652 receives the pressure from the inside of the fuel switch 6, the sealing plug 652 is tightly crimped with the rigid sealing ring 651, so that the valve body 65 is in a closed state; When the plug 652 receives pressure from the outside of the fuel switch 6, the return spring 653 is compressed, and the sealing plug 652 is separated from the rigid sealing ring 651, so that the valve
  • the pulverized coal conveying air from the pulverized coal branch pipe 502 has a certain pressure.
  • the sealing plug 652 When passing through the pulverized coal inlet 62, the sealing plug 652 is pushed from the outside, and the return spring 653 is The pulverized coal inlet 62 is compressed to open the pulverized coal inlet 62 and the fuel outlet 64.
  • the sealing plug 652 is subjected to the pulverized coal conveying air from the pulverized coal branch pipe 502
  • the pressure is from the outside of the fuel switch 6; when the pulverized coal conveying air enters the fuel switch 6 from the pulverized coal inlet 62, the air pressure of the pulverized coal conveying air will seal the gas inlet 61 and the nitrogen inlet 63
  • the plug 652 compresses the rigid sealing ring 651 to ensure the airtightness of the gas inlet 61 and the nitrogen inlet 63.
  • the sealing plug 652 at the gas inlet 61 and the nitrogen inlet 63 is subjected to pressure from the inside of the fuel switch 6.
  • the support steel body 66 is arranged in the center of the fuel switch 6 and its position is fixed.
  • One end of the return spring 653 is connected to the support steel body 66, and the other end of the return spring 653 is connected to the sealing plug 652.
  • the sealing plug 652 can follow the return spring When the fuel delivery is completed, the return spring 653 resets and drives the sealing plug 652 to press the rigid sealing ring 651, thereby controlling the opening and closing of the gas inlet 61, the pulverized coal inlet 62 and the nitrogen inlet 63, avoiding the gap between the inlets. Connect with each other.
  • the rigid sealing ring 651 is arranged around each inlet.
  • the diameter of the rigid sealing ring 651 is slightly larger than the diameter of the inlet, and the size of the sealing plug 652 should be larger than the diameter of the rigid sealing ring 651 to ensure the sealing performance of each inlet. If the rigid sealing ring 651 is not provided, the sealing plug 652 directly blocks the inlet of the fuel switch 6. The sealing performance of this surface contact seal is poor, and the rigid sealing ring 651 and the sealing plug 652 are crimped, which will cause the valve body 65 has good airtightness to ensure the effect of fuel switching.
  • the valve body shown in Fig. 10 has a simple structure, which can reduce the equipment cost of the lime kiln. By spontaneously sensing the pressure from the inside and outside of the fuel switch 6, the opening and closing of the valve body 6 is automatically controlled without sending an electric control signal for control. The sealing performance and control efficiency of the valve body 65 are improved.
  • the fuel in the kiln 1 When the fuel in the kiln 1 returns, it may enter the fuel switch 6 from the fuel outlet 64. At this time, the sealing plugs 652 of the valve body 65 at the gas inlet 61, the pulverized coal inlet 62 and the nitrogen inlet 63 are all exposed to the fuel The pressure inside the switch 6 and the return spring 653 can make the three valve bodies 65 closed. The three inlets of the fuel switch 6 have good sealing properties to ensure that the returning fuel will not enter the gas branch pipe 402, coal Powder branch pipe 502 and nitrogen branch pipe 73. When switching fuel, the nitrogen purging device 7 is used to blow the return fuel remaining in the fuel switch 6 into the spray gun 31 again, and the spray gun 31 can be sprayed back into the kiln 1.
  • 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, the outlet end of the gas return pipe 409 and the gas conveying fan
  • the inlet end of 406 is connected, the inlet end of the gas return pipe 409 is connected to the gas delivery pipe 407, and the inlet end of the gas return pipe 409 is located between the gas shut-off valve 408 and the outlet end of the gas delivery fan 406.
  • the gas return valve 410 is opened At this time, the gas conveying air can be circulated 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 pipeline.
  • the pulverized coal supply device 5 also includes a pulverized coal return pipeline 508.
  • the pulverized coal return pipeline 508 is provided with a pulverized coal return valve 509.
  • the outlet end of the pulverized coal return pipeline 508 is connected to the inlet end of the pulverized coal conveying fan 505.
  • the pulverized coal return pipeline The inlet end of 508 is connected 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.
  • the pulverized coal conveying air circulates between the pulverized coal return pipe 508 and the pulverized coal conveying fan 505 to release the pressure of the pulverized coal conveying fan 505, thereby ensuring the safety of the pulverized coal supply pipeline.
  • the lime kiln described in the third embodiment may further include a computer control unit configured to execute the program steps described in the fourth embodiment below.
  • the fourth embodiment of the present application provides a lime kiln heating method, which is used in the lime kiln structure as described in the third embodiment, and the method includes:
  • the single gas heating mode will be activated first, so that all the N spray guns are directed
  • the kiln conveys gas fuel;
  • the single gas heating mode is: the gas shut-off valve 408, the gas conveying fan 406, and the valve body 65 at the gas inlet 61 of the N fuel switches 6 are all open, and the pulverized coal shut-off valve 507
  • the valve bodies 65 at the pulverized coal inlet 62 in the N fuel switches 6 are all closed, the pulverized coal conveying fan 505 is in standby state, the nitrogen shut-off valve 76 and the valve body at the nitrogen inlet 63 in the N fuel switches 6 65 are all closed;
  • the gas return valve 410 is closed, and the pulverized coal return valve 509 is open;
  • N m is the theoretical number of spray guns that need to switch the fuel medium.
  • the uniform heating mode is used to indicate that when N m is within a specified value range, the position of the spray gun in the spray gun group that needs to switch the fuel medium and the actual number of spray guns N x , N m ⁇ N x ⁇ N.
  • the uniform heating threshold N y is determined .
  • the distribution state of the spray guns on the kiln bore section described here includes the division of the annular heating area, and the number of spray guns included in the spray gun matrix in each annular heating area and the distribution position and status of each spray gun.
  • N x is equal to N, so that the uniform heating mode is a single pulverized coal heating
  • N x is equal to 0, so that the uniform heating mode is single gas heating.
  • the uniform heating mode that needs to be adopted can be determined according to the value range of N m .
  • the uniform heating mode when it is determined that the uniform heating mode is a single pulverized coal heating, it is necessary to switch the fuel of all N spray guns from coal gas to pulverized coal synchronously.
  • start the uniform heating mode as follows:
  • the uniform heating mode when it is determined that the uniform heating mode is the combined heating of coal gas and pulverized coal, the uniform heating mode can be used to know which parts of the spray gun group 3 will be fueled by the spray guns. Switching from gas to pulverized coal and the actual number of spray guns N x that need to switch the fuel medium is to switch the fuel of some of the N spray guns from gas to pulverized coal. In the aforementioned single gas heating mode, follow the steps below Start the uniform heating mode:
  • the corresponding pulverized coal branch and nitrogen branch are cut off, and only the gas branch remains conductive. Therefore, the NN x spray guns 31 spray The fuel medium is still gas, which will not be affected by subsequent nitrogen purging and switching to pulverized coal.
  • the gas passes through the gas pipeline 407, the gas loop 401, NN x gas branch pipes 402, and NN x coal gas from the fuel switch 6 in sequence.
  • the inlet 61 and the fuel outlet 64, as well as NN x spray guns 31, flow into the kiln 1.
  • the corresponding gas branch is cut off.
  • the nitrogen supply pipeline can be opened according to the following step (E) to purge the residual gas inside the fuel switch 6 to ensure that the spray guns 31 will not blow out Mixed fuel of coal gas and pulverized coal.
  • nitrogen N shutoff valve 76 When the nitrogen N shutoff valve 76 is opened, nitrogen gas is turned general line, a nitrogen from the nitrogen loop strip N x N x branches nitrogen guns 31 into the corresponding portion 72, and the fuel corresponding to the switches 6 x After the remaining gas is purged and sent to the respective spray guns 31, the nitrogen branch can be cut off, and the next step (F) is prepared to switch the fuel of the N x spray guns 31 at the location from gas to pulverized coal.
  • the gas conveying fan 406 and the pulverized coal conveying fan 505 can operate normally at the same time.
  • the pulverized coal conveying fan 505 is used to convey pulverized coal to the N x spray guns 31 in the position, and the gas conveying fan 406 is used to convey pulverized coal to the other NN x
  • One spray gun 31 delivers gas. Since each spray gun 31 has a corresponding gas branch control valve 403, a pulverized coal branch control valve 503, and a nitrogen branch control valve 74, it can ensure that the gas supply device 4 and the pulverized coal supply device 5 can simultaneously supply fuel , And will not interfere with each other, so it can realize the combined heating of coal gas and coal.
  • the startup mode and control method of these three modes are the valve bodies 65 at the three inlets inside the fuel switch 6
  • the valve body structure shown in Figure 6 can be used, such as a traditional solenoid valve, etc., or a specially designed pressure-sensitive automatic regulating valve as shown in Figure 10 can be used, as long as it can achieve the three inlets of the fuel switch 6 Just seal and open and close.
  • the pulverized coal supply device and the gas supply device are combined and isolated by a fuel switcher, and by controlling the opening and closing status of each valve in the lime kiln and the operation status of the fan, the switch can be quickly, automatically and flexibly
  • the lime kiln fuel medium realizes diversified heating modes, thereby overcoming the shortcomings of single heating fuel type and poor production adaptability of the lime kiln.
  • this scheme divides the cross section of the lime kiln into several heating areas along the radial direction.
  • each heating area obtains the total heat supply required by each heating area, so as to accurately calculate and implement the fuel supply required by each independent spray gun, so as to achieve precise heating and make the kiln chamber the same
  • the materials at different positions on the horizontal section are evenly heated to avoid over-burning or raw burning of lime, thereby improving the quality of the lime kiln product. Therefore, the present application can significantly improve the performance of the lime kiln.
  • the fuel sprayed by the spray gun is mainly concentrated at the outlet of the spray gun, but the area between the spray gun and the spray gun does not distribute fuel, that is, the fuel is in
  • the uneven distribution on the cross section of the kiln leads to high material temperature at the spray gun outlet and relatively low material temperature in the area between the spray gun and the spray gun. This makes the limestone calcination rate different on the same cross section of the kiln and affects the quality of the finished quicklime.
  • Embodiment 5 of the present application specifically provides a structure of a spray gun 31, including a spray gun body 3101, which is respectively provided with The inlet 3102 and the outlet 3103, the spray gun body 3101 includes an inner tube body 3104 and an outer tube body 3105.
  • the outer tube body 3105 is sleeved on the outside of the inner tube body 3104.
  • the inner tube body 3104 and the outer tube body 3105 are both It is a hollow tube structure, the inner tube body 3104 is provided with an inner fuel channel 3106, the diameter of the inner tube body 3104 is smaller than the diameter of the outer tube body 3105, so that the inner tube body 3104 and the outer tube body 3105 A ring-shaped outer fuel passage 3107 is formed.
  • a section of the outer tube body 3105 close to the outlet 3103 is provided with a plurality of diversion hole groups 3108 spaced along the axial direction.
  • the diversion hole group 3108 includes a plurality of distribution holes 3109 evenly distributed along the circumference.
  • the calcining process temperature of the lime kiln is about 1100°C, and the spray gun body 3101 can be made of high temperature resistant materials, which can be selected according to actual applications.
  • the spray gun provided in this embodiment is based on a dual-channel structure.
  • Fuel including coal gas, pulverized coal, etc.
  • the outlet 3103 is the main outlet of the spray gun body 3101. Most of the fuel is sprayed through the main outlet.
  • the sub-circulation holes 3109 provided on the outer tube body 3105 are equivalent to the auxiliary outlets of the spray gun body and flow into the outer fuel channel.
  • a small part of the fuel of 3107 is sprayed through the distribution hole 3109, which effectively increases the spreading range of a single spray gun, thereby distributing fuel to the area between the spray gun and the spray gun, so as to ensure the uniformity of temperature distribution on the same section of the kiln and improve the quicklime The quality of the finished product.
  • the spray gun body in order to facilitate the material guide of the spray gun, can be divided into a horizontal section 3110, a circular arc transition section 3111 and a vertical section 3112.
  • the horizontal section 3110 and the vertical section 3112 are connected by the circular arc transition section 3111;
  • 3102 is set at the open end of the horizontal section 3110, such as the left end of the horizontal section 3110 in Figure 11;
  • the outlet 3103 is set at the open end of the vertical section 3112, such as the bottom end of the vertical section 3112 in Figure 11, and a number of diversion hole groups 3108 It is arranged on the outer tube body 3105 corresponding to the vertical section 3112.
  • the horizontal section 3110, the arc transition section 3111, and the vertical section 3112 may be provided as an integral structure, or alternatively, a method such as segmented welding may also be selected, which is not limited in this application.
  • the spreading range of the existing lime kiln spray gun is only the area S1 below the outlet, and the sprayed fuel falls in the area where S1 is located, so that the fuel cannot be distributed between the spray gun and the spray gun. , Resulting in uneven temperature distribution in the kiln chamber section.
  • the fuel flowing into the outer fuel channel 3107 will flow out of the sub-circulation holes 3109 after falling into the area of the vertical section 3112, so that the fuel spreading range is expanded, and the spreading range is larger than S1.
  • the central axis of the inner tube body 3104 coincides with the central axis of the outer tube body 3105 to ensure that the distribution of the fuel flowing out of the sub-circulation holes 3109 is more even and symmetric; the sub-circulation holes 3109 are directed
  • the downwardly inclined through hole that is, the central axis of the sub-circulation hole 3019 and the central axis of the vertical section 3112 have an inclination angle ⁇ , so that the spray gun spreading range is S1+S2, where S1 is constant, and S2 is a number of branch hole groups 3108
  • the split hole group with the largest height in the vertical direction in Figure 13 has the largest spray range.
  • the value of S2 is related to the design height of the split hole group 3108 and the inclination angle ⁇ .
  • the spraying range of the spray gun is no longer limited.
  • the fuel spraying range is increased from the original S1 to S1+S2, which can not only act on the outlet, but also on the spray gun and the spray gun.
  • the fuel distribution is more in place and uniform, and the temperature distribution of the kiln hearth section of the lime kiln is also more uniform, thereby improving the quality of the finished quicklime product, thereby improving the performance of the lime kiln.

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PCT/CN2020/086384 2019-04-25 2020-04-23 一种石灰窑及其供热方法 WO2020216289A1 (zh)

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