CN116217099A - Double-hearth kiln using low-calorific-value fuel and calcining method - Google Patents
Double-hearth kiln using low-calorific-value fuel and calcining method Download PDFInfo
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- CN116217099A CN116217099A CN202310252247.1A CN202310252247A CN116217099A CN 116217099 A CN116217099 A CN 116217099A CN 202310252247 A CN202310252247 A CN 202310252247A CN 116217099 A CN116217099 A CN 116217099A
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- 239000000446 fuel Substances 0.000 title claims abstract description 57
- 238000001354 calcination Methods 0.000 title claims abstract description 54
- 238000000034 method Methods 0.000 title claims abstract description 17
- 239000007789 gas Substances 0.000 claims abstract description 144
- 239000002737 fuel gas Substances 0.000 claims abstract description 21
- 239000002912 waste gas Substances 0.000 claims description 40
- 238000002485 combustion reaction Methods 0.000 claims description 31
- 238000001816 cooling Methods 0.000 claims description 16
- 238000010438 heat treatment Methods 0.000 claims description 15
- 238000005192 partition Methods 0.000 claims description 6
- 230000009977 dual effect Effects 0.000 claims description 5
- 238000007599 discharging Methods 0.000 claims description 3
- 239000000725 suspension Substances 0.000 claims description 3
- 235000008733 Citrus aurantifolia Nutrition 0.000 abstract description 13
- 235000011941 Tilia x europaea Nutrition 0.000 abstract description 13
- 239000004571 lime Substances 0.000 abstract description 13
- 230000000694 effects Effects 0.000 abstract description 2
- 235000019738 Limestone Nutrition 0.000 description 19
- 239000006028 limestone Substances 0.000 description 19
- 238000004519 manufacturing process Methods 0.000 description 7
- 238000004364 calculation method Methods 0.000 description 4
- 238000000354 decomposition reaction Methods 0.000 description 4
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 4
- 239000003245 coal Substances 0.000 description 3
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 2
- 238000007405 data analysis Methods 0.000 description 2
- 239000003546 flue gas Substances 0.000 description 2
- 238000005338 heat storage Methods 0.000 description 2
- 239000003345 natural gas Substances 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 238000009825 accumulation Methods 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 230000000903 blocking effect Effects 0.000 description 1
- 239000004566 building material Substances 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 239000005431 greenhouse gas Substances 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000004321 preservation Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
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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
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- Ceramic Engineering (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Materials Engineering (AREA)
- Structural Engineering (AREA)
- Organic Chemistry (AREA)
- Furnace Details (AREA)
- Feeding, Discharge, Calcimining, Fusing, And Gas-Generation Devices (AREA)
Abstract
The invention relates to a double-hearth kiln using low-calorific-value fuel and a calcination method. And an exhaust gas suction beam is arranged between the calcining section and the preheating section of the first kiln chamber and the second kiln chamber respectively. The fuel pipeline and the exhaust gas suction beam are respectively connected with the gas-exhaust gas heat exchanger, and the low-heat-value gas heated by the gas-exhaust gas heat exchanger is connected with the inserted burner arranged in the first kiln chamber and the second kiln chamber calcining zone. According to the invention, the exhaust gas suction beam is arranged in the kiln chamber, and the extracted high-temperature exhaust gas is utilized to exchange heat for the low-heat-value fuel gas, so that the effect of calcining lime by the low-heat-value fuel gas is improved, the low-heat-value fuel is fully utilized, and the quality of a calcined product is improved.
Description
Technical Field
The invention belongs to the technical field of chemical building material production, relates to an industrial kiln, and in particular relates to a double-hearth kiln using low-calorific-value fuel and a calcination method.
Background
The double-hearth kiln is also called a double-hearth parallel-flow heat accumulating lime kiln, and fuel enters from the upper end of the calcining zone and flows parallel to the raw materials. Since the fuel is injected from the upper part of the calciner zone, the raw material is here able to absorb most of the heat released by the fuel. Another important feature of the double-chamber kiln is the heat storage, which is used to preheat a portion of the combustion air. The thermal characteristics of co-current calcination and counter-current heat storage determine that double-hearth kilns have high thermal efficiency, with heat energy consumption being the lowest in all types of lime kilns, including rotary kilns, sleeve kilns, and the like.
In the production process of metallurgical enterprises, a large amount of blast furnace gas is generated, which is a precious fuel resource, and the heat value of the blast furnace gas is 3000-3400 kJ/Nm 3 Because the low-calorific-value fuel cannot be directly used for calcining limestone, a large amount of low-calorific-value fuel cannot be fully obtainedUtilization. And the lime production also needs to purchase high-calorific-value fuel, so that resource waste is caused, and economic benefit is influenced.
Disclosure of Invention
The invention aims to provide a double-hearth kiln using low-heat-value fuel and a calcination method, so that the low-heat-value fuel such as blast furnace gas and the like can be used for calcining lime, low-heat-value fuel resources are fully utilized, and economic benefit is improved.
According to a first aspect, embodiments of the present application provide a dual-chamber kiln using a low heating value fuel, including a dual-chamber kiln body, a feeding device, a discharging device, an air supply system, a fuel line, and an exhaust gas discharge system; the double-hearth kiln body comprises a first kiln hearth and a second kiln hearth, and a preheating zone, a calcining zone and a cooling zone are respectively arranged in the first kiln hearth and the second kiln hearth; the calcining zone is provided with an inserted burner; the method is characterized in that: an exhaust gas suction beam is arranged between the calcining section and the preheating section of the first kiln chamber and the second kiln chamber respectively; the outlet of the exhaust gas suction beam is connected with the shell side of the gas-exhaust gas heat exchanger, and the shell side outlet of the gas-exhaust gas heat exchanger is connected with an exhaust gas discharge system; the fuel pipeline is connected with a tube side of the gas-exhaust gas heat exchanger, and a tube side outlet of the gas-exhaust gas heat exchanger is connected with the plug-in burner.
Specifically, the double-hearth kiln is a double-hearth kiln with a suspension cylinder structure or a bracket structure.
Specifically, the exhaust gas suction beam is of a square partition wall structure, an exhaust gas channel is arranged in the exhaust gas suction beam, and a partition wall is a cooling air channel; and an outlet of the exhaust gas suction beam cooling air channel is connected with a combustion air main pipe.
Specifically, the air suction port of the exhaust gas suction beam is arranged at the lower part of the exhaust gas suction beam; the number of the air suction holes of each exhaust air suction beam is 10 to 12.
According to a second aspect, embodiments of the present application provide a method for calcining a dual-chamber kiln using low-heating-value fuel, wherein when a first chamber is being calcined, a shut-off valve of an exhaust gas suction beam in the first chamber is in a closed state, and a shut-off valve of low-heating-value fuel gas is in an open state; the cut-off valve of the waste gas suction beam in the second kiln chamber is in an open state, and the cut-off valve of the low-heat-value fuel gas is in a closed state; the high-temperature waste gas split by the second kiln chamber exchanges heat with the low-heat value gas entering the first kiln chamber through the gas waste gas heat exchanger, and the high-temperature low-heat value gas after heat exchange enters an inserted burner of the first kiln chamber to be calcined. After the reversing calcination of the double-hearth kiln, when the second kiln hearth is calcined, the cut-off valve of the exhaust gas suction beam in the second kiln hearth is in a closed state, and the cut-off valve of the low-heat-value fuel gas is in an open state; the cut-off valve of the waste gas suction beam in the first kiln chamber is in an open state, and the cut-off valve of the low-heat-value fuel gas is in a closed state; the high-temperature waste gas split by the first kiln chamber exchanges heat with the low-heat value fuel gas entering the second kiln chamber through a fuel gas waste gas heat exchanger; and the high-temperature low-calorific-value fuel gas subjected to heat exchange enters an inserted burner of the second kiln chamber for calcination.
Specifically, in the middle reversing process, the cut-off valves of the exhaust gas suction beam pipeline and the gas pipeline are closed.
Specifically, in the reversing and calcining stages of the double-hearth kiln, cooling air is continuously conveyed to each exhaust gas suction beam, so that the service life of the exhaust gas suction beams is ensured.
According to the double-hearth kiln using the low-heat-value fuel, a large amount of high-temperature waste gas formed after the low-heat-value fuel is combusted is pumped, so that on one hand, the proportion of the residual waste gas and combustion air in the kiln hearth is favorably adjusted, on the other hand, the fuel can be preheated by utilizing the sensible heat of the pumped high-temperature waste gas, so that the combustion temperature of the low-heat-value fuel is improved, the low-heat-value fuel such as blast furnace gas can be used for calcining lime, the low-heat-value fuel resource is fully utilized, and the economic benefit is improved. In addition, the hot air exhausted by the cooling waste gas suction beam can be used for supporting combustion, so that the combustion temperature can be increased, the fuel can be saved, the emission of greenhouse gases can be reduced, and the environment protection is facilitated. The invention has simple structure and easy implementation, and can be used for the transformation of the traditional lime double-chamber kiln.
Drawings
FIG. 1 is a schematic diagram of a dual chamber kiln using low heating value fuel according to the present invention;
wherein: 1-first kiln chamber, 2-second kiln chamber, 3-plug-in burner, 4-fuel pipeline, 5-waste gas suction beam, 6-gas waste gas heat exchanger, 7-waste gas induced draft fan and 8-chimney.
Description of the embodiments
The present invention will be described in detail with reference to examples and drawings. The scope of the invention is not limited to the examples and any modifications made by a person skilled in the art within the scope of the invention as defined by the claims are also within the scope of the invention.
Limestone calcination requires the combustion of fuel in the calciner to give off heat to heat the material being calcined. The decomposition temperature of the limestone is about 900 ℃, and the higher the combustion temperature of the fuel is, the higher the temperature difference between the decomposition temperature of the limestone and the decomposition temperature of the limestone is, the higher the calcining capability is. The calcination temperature of the high-calorific-value fuel is generally 1050-1200 ℃, and the calcination temperature of the low-calorific-value gas is less than 1000 ℃. The same size double chamber kiln uses fuels of different heating values, and the lime yields are not the same and differ greatly. The low-calorific-value fuel is combusted to a temperature which is less than the required temperature, so that the limestone cannot be decomposed; or the temperature is low, the limestone is not completely decomposed, and the problems of low quality of the calcined lime product and the like are caused. The combustion temperatures of the fuels of different heating values are shown in table 1.
TABLE 1 Combustion temperatures of fuels of different calorific values
| Fuel and its production process | Heating value (kcal/m) 3 ） | Theoretical combustion temperature (. Degree. C.) | Calcination temperature (. Degree. C.) | Yield (t) |
| Natural gas | 8400 | 1950 | 1200 | 600 |
| Pulverized coal | 6000 | 1800 | 1190 | 600 |
| Converter gas | 1200 | 1610 | 1050 | 400 |
| Blast furnace gas | 840 | 1390 | 950 | -- |
The double-hearth kiln is provided with two kiln hearths, and each kiln hearth is provided with a preheating zone, a calcining zone and a cooling zone. The preheating zone, the calcining zone and the cooling zone are sequentially arranged from top to bottom. The auxiliary combustion air in one kiln chamber is heated by a preheating zone and then mixed with fuel in a calcining zone for burning, the air flow and limestone flow downwards for heating and calcining, the flue gas and the air of which the lower part is cooled by lime are converged in a connecting channel between the two kiln chambers, and enter the other kiln chamber to move upwards together with the air of which the kiln chamber is cooled by lime, so that the countercurrent downward limestone is preheated and the exhaust temperature of waste gas is reduced. The waste gas stores heat through limestone in the preheating section of one kiln chamber, and the combustion air takes away heat through the preheating zone of the other kiln chamber, so that the waste gas can be reduced to below 150 ℃ through repeated switching. By comparing the exhaust gas amounts after burning the fuels with different heat values with the exhaust gas temperatures, the exhaust gas temperature of the high heat value fuel is about 110-120 ℃, the exhaust gas temperature of the low heat value gas is about 180-200 ℃, and the lower the heat value is, the higher the exhaust gas temperature is. Meanwhile, the ratio of the combustion air quantity of the high-heat-value gas to the exhaust gas quantity is about 45-50%, the ratio of the combustion air quantity of the low-heat-value gas to the exhaust gas quantity is less than 30%, and the ratio of the combustion air quantity to the exhaust gas quantity is lower when the heat value of the gas is lower.
There are two main reasons why the exhaust gas temperature of the double-hearth kiln burning low-calorific-value gas is high. The first is that the combustion-supporting air quantity is insufficient, the temperature of the limestone in the preheating zone cannot be fully cooled, the limestone cannot fully absorb the heat of the waste gas after reversing, and the temperature of the waste gas is reduced. And the second is that the calcination temperature of the low-calorific-value gas is low, and the heat cannot be quickly absorbed by limestone decomposition reaction, so that the temperature of the waste gas when entering another kiln chamber is higher. Table 2 lists the exhaust parameters for fuels of different heating values.
TABLE 2 exhaust gas parameters for fuels of different calorific values
| Fuel and its production process | Heating value (kcal/m) 3 ） | Yield (t/d) | Combustion air quantity (m) 3 /h) | Exhaust gas quantity (m) 3 /h) | Exhaust gas temperature (. Degree. C.) | Air to exhaust ratio/% |
| Natural gas | 8400 | 600 | 29370 | 65900 | ＜110 | 44.56 |
| Pulverized coal | 6000 | 600 | 31830 | 68300 | ＜120 | 46.6 |
| Converter gas | 1200 | 400 | 14360 | 49300 | 180 | 29.1 |
| Blast furnace gas | 840 | 400 | 14460 | 54960 | Greater than 200 | 26.3 |
The waste gas generated in the limestone calcining process in the double-hearth kiln is subjected to heat accumulation through the limestone in the preheating section to reduce the temperature, and then the heat is taken away through the combustion air. In a dual chamber kiln for low heating value fuels, the amount and temperature of the exhaust gas is much greater than that of Gao Rezhi fuel. The combustion air is thus not able to cool the limestone sufficiently, so that the downstream equipment is not able to be used normally. If a part of the exhaust gas is branched off in the calcination section and the preheating section and the ratio of the remaining exhaust gas to combustion air is adjusted, the outlet temperature of the exhaust gas can be lowered.
The invention provides a double-hearth kiln using low-calorific-value fuel, which is of a suspension cylinder structure or a bracket structure. As shown in fig. 1, the double-hearth kiln comprises a double-hearth kiln body, a feeding device, a discharging device, an air supply system, a fuel pipeline 4 and an exhaust gas discharge system. Specifically, the double-hearth kiln body comprises a first kiln hearth 1 and a second kiln hearth 2. A preheating zone, a calcining zone and a cooling zone are respectively arranged in the first kiln chamber 1 and the second kiln chamber 2, and an inserted burner 3 is arranged in the calcining zone of each kiln chamber. An exhaust gas suction beam 5 is arranged between the calcining section and the preheating section of the first kiln chamber 1 and the second kiln chamber 2 respectively. Specifically, two exhaust gas suction beams may be disposed in the first kiln chamber, and two exhaust gas suction beams may be disposed in the second kiln chamber.
The outlet of the exhaust gas suction beam 5 is connected with the shell side of the gas-exhaust gas heat exchanger 6, and the shell side outlet of the gas-exhaust gas heat exchanger 6 is connected with an exhaust gas discharge system consisting of an exhaust gas induced draft fan 7 and a chimney 8. The fuel pipeline 4 is connected with a tube side of the gas-exhaust heat exchanger 6, and a tube side outlet of the gas-exhaust heat exchanger 6 is connected with the plug-in burner 3.
Specifically, the exhaust gas suction beam 5 may have a square partition wall structure, an exhaust gas channel is formed inside, and a partition wall is a cooling air channel. The outlet of the cooling air channel in the exhaust gas suction beam 5 is connected with a combustion air main pipe, and the air temperature of the exhaust gas suction beam after dividing wall cooling is increased can be used as combustion air for calcining lime.
In order to prevent the limestone from blocking the suction port, the suction port of the offgas suction boom 5 may be provided at a lower portion of the offgas suction boom. The number of suction holes of one suction beam is generally 10-12, and the size of the suction holes is determined according to the yield and the exhaust gas amount. Further, the number of exhaust gas suction beams provided in each kiln chamber may be determined according to the production amount and the exhaust gas amount.
Blast furnace gas (heat) fired according to 400t/d productionValue 840 kcal/m 3) double-chamber kiln data analysis, combustion air quantity 14460 m 3 Per hour, according to the air-waste gas proportion of 45%, the main waste gas flow is 32000 and 32000 m 3 /h, the amount of exhaust gas passing through exhaust gas suction Liang Yinliu is 22960m 3 And/h. The drainage waste gas pipeline needs heat preservation protection.
An effective method for solving the problem that the double-hearth kiln cannot burn the low heat value is to increase the combustion temperature, and the combustion temperature can be effectively increased by increasing the temperature of the low heat value gas. The gas-to-exhaust heat exchanger 6 can effectively reduce the exhaust gas temperature and increase the gas temperature.
The temperature of the exhaust gas at the position between the calcining section and the preheating section of the double-hearth kiln can reach 500-600 ℃, and the separated exhaust gas can be used for preheating low-heat-value gas. Blast furnace gas (calorific value 840 kcal/m) fired according to 400 ton production 3 ) Is used for data analysis of the double-chamber kiln, and the drainage waste gas amount is 22960m 3 /h, temperature 600 ℃, blast furnace gas flow rate 18850m 3 And/h. The heat exchange is carried out through a gas waste gas heat exchanger 6, the heat exchanger adopts a tube plate structure, the tube side is filled with gas, and the shell side is filled with high-temperature waste gas.
The preheating temperature of the blast furnace gas can be calculated by using the formula (1).
Wherein,,t m preheating blast furnace gas at the temperature of DEG C;v f for exhaust gas flow, 22960m 3 /h；t f1 The temperature is 600 ℃ for the inlet temperature of the waste gas;c f1 for the specific heat capacity of the exhaust gas inlet, 1.55 kJ/(m) 3 ·℃)；t f2 The temperature of the exhaust gas outlet is 150 ℃;c f2 for the specific heat capacity of the exhaust gas outlet, 1.436 kJ/(m) 3 ·℃)；v m For blast furnace gas flow, 18850m 3 /h；c m Is the specific heat capacity of blast furnace gas, 1.506 kJ/(m) 3 ·℃)。
The preheating temperature of the blast furnace gas can be obtained through calculation and can reach 598 ℃. By theoretical combustion formula (see formula 2) The combustion temperature t of the blast furnace gas can be calculated i 。
Wherein Q is the calorific value of blast furnace gas, 840 x 4.18kJ/m 3 ；t m The preheating temperature of the blast furnace gas is 598 ℃;c m is the specific heat capacity of blast furnace gas, 1.506 kJ/(m) 3 ·℃)；v a The gas amount generated by burning unit fuel under a certain air coefficient is 1.6m 3 /m 3 ；c y For the specific heat capacity of the flue gas, 1.616 kJ/(m) 3 ·℃)。
The combustion temperature of the blast furnace gas is 1706 ℃ which is slightly lower than the combustion temperature of the pulverized coal and higher than the combustion temperature of the converter gas through calculation. The calculation shows that the calcination temperature can reach about 1100 ℃, and the calcination requirement of limestone can be completely met.
The operation process of the double-hearth kiln using the low-calorific-value fuel provided by the invention comprises the following steps:
when the first kiln chamber 1 is calcined, the cut-off valve of the waste gas suction beam 5 in the first kiln chamber 1 is in a closed state, and the cut-off valve of the low-heat-value fuel gas is in an open state; the shut-off valve of the exhaust gas suction beam 5 in the second kiln chamber 2 is in an open state, and the shut-off valve of the low-calorific-value fuel gas is in a closed state. The high-temperature waste gas split by the second kiln chamber 2 exchanges heat with the low-heat value gas entering the first kiln chamber 1 through the gas waste gas heat exchanger 6, and the high-temperature low-heat value gas after heat exchange enters an inserted burner of the first kiln chamber 1 for calcination.
After the reversing calcination of the double-hearth kiln, when the second kiln hearth 2 is calcined, the cut-off valve of the waste gas suction beam 5 in the second kiln hearth 2 is in a closed state, and the cut-off valve of the low-heat-value fuel gas is in an open state; the shut-off valve of the exhaust gas suction beam 5 in the first kiln chamber 1 is in an open state, and the shut-off valve of the low-calorific-value fuel gas is in a closed state. The high-temperature exhaust gas split by the first kiln chamber 1 exchanges heat with the low-heat value fuel gas entering the second kiln chamber 2 through a fuel gas and exhaust gas heat exchanger 6; the high-temperature low-calorific-value fuel gas after heat exchange enters an inserted burner of the second kiln chamber 2 for calcination.
In the middle reversing process, the cut-off valve connecting each exhaust gas suction beam pipeline and the gas pipeline is closed. In the reversing and calcining stage of the double-hearth kiln, cooling air is continuously supplied to each exhaust gas suction beam 5, so that the service life of the exhaust gas suction beams 5 is ensured.
Through theoretical calculation and analysis of the data of the currently operated double-hearth kiln, after the suction beam and the gas heat exchanger are added, the yield of the double-hearth kiln for combusting blast furnace gas can reach 400-450 tons/day. The activity and the raw overburning rate of the lime can reach the average level of the double-hearth kiln, and can completely meet the requirements of various clients.
The calcination temperature of the low-calorific-value gas can be effectively enhanced by means of adding the suction beam, the gas heat exchanger and the like, the exhaust temperature of waste gas is reduced, and the limestone product can meet the corresponding requirements.
Claims (7)
1. A double-hearth kiln using low-calorific-value fuel comprises a double-hearth kiln body, feeding equipment, discharging equipment, an air supply system, a fuel pipeline (4) and an exhaust gas emission system; the double-hearth kiln body comprises a first kiln hearth (1) and a second kiln hearth (2), wherein a preheating zone, a calcining zone and a cooling zone are respectively arranged in the first kiln hearth (1) and the second kiln hearth (2); the calcining zone is provided with an inserted burner (3); the method is characterized in that: an exhaust gas suction beam (5) is arranged between the calcining section and the preheating section of the first kiln chamber (1) and the second kiln chamber (2) respectively; the outlet of the exhaust gas suction beam (5) is connected with the shell side of the gas-exhaust gas heat exchanger (6), and the shell side outlet of the gas-exhaust gas heat exchanger (6) is connected with an exhaust gas discharge system; the fuel pipeline (4) is connected with a tube side of the gas-exhaust gas heat exchanger (6), and a tube side outlet of the gas-exhaust gas heat exchanger (6) is connected with the plug-in burner (3).
2. The dual chamber kiln using low heating value fuel of claim 1, characterized in that: the double-hearth kiln is of a suspension cylinder structure or a bracket structure.
3. The dual chamber kiln using low heating value fuel of claim 2, characterized in that: the exhaust gas suction beam (5) is of a square partition wall structure, an exhaust gas channel is arranged in the exhaust gas suction beam, and a partition wall is a cooling air channel; and an outlet of the cooling air channel of the waste gas suction beam (5) is connected with a combustion air main pipe.
4. The dual chamber kiln using low heating value fuel of claim 1, characterized in that: the air suction port of the waste gas suction beam (5) is arranged at the lower part of the waste gas suction beam (5); the number of the air suction holes of each exhaust air suction beam (5) is 10 to 12.
5. A method of calcining in a double-hearth kiln using a low heating value fuel as claimed in claim 1, characterized by: when the first kiln chamber (1) is calcined, a cut-off valve of an exhaust gas suction beam (5) in the first kiln chamber (1) is in a closed state, and a cut-off valve of low-heat-value fuel gas is in an open state; the cut-off valve of the waste gas suction beam (5) in the second kiln chamber (2) is in an open state, and the cut-off valve of the low-heat-value fuel gas is in a closed state; the high-temperature waste gas split by the second kiln chamber (2) exchanges heat with the low-heat value gas entering the first kiln chamber (1) through a gas waste gas heat exchanger (6), and the high-temperature low-heat value gas after the heat exchange enters an inserted burner of the first kiln chamber (1) for calcination;
after the reversing calcination of the double-hearth kiln, when the second kiln hearth (2) is calcined, the cut-off valve of the waste gas suction beam (5) in the second kiln hearth (2) is in a closed state, and the cut-off valve of the low-heat-value fuel gas is in an open state; the cut-off valve of the waste gas suction beam (5) in the first kiln chamber (1) is in an open state, and the cut-off valve of the low-heat-value fuel gas is in a closed state; the high-temperature exhaust gas split by the first kiln chamber (1) exchanges heat with the low-heat value gas entering the second kiln chamber (2) through a gas-exhaust gas heat exchanger (6); the high-temperature low-calorific-value fuel gas after heat exchange enters an inserted burner of the second kiln chamber (2) for calcination.
6. The calcination method according to claim 5, characterized in that: in the middle reversing process, the cut-off valves of the exhaust gas suction beam (5) pipeline and the gas pipeline are closed.
7. The calcination method according to claim 5, characterized in that: and in the reversing and calcining stages of the double-hearth kiln, cooling air is continuously supplied to each exhaust gas suction beam (5), so that the service life of the exhaust gas suction beams (5) is ensured.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310252247.1A CN116217099A (en) | 2023-03-16 | 2023-03-16 | Double-hearth kiln using low-calorific-value fuel and calcining method |
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| CN202310252247.1A CN116217099A (en) | 2023-03-16 | 2023-03-16 | Double-hearth kiln using low-calorific-value fuel and calcining method |
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Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101857383A (en) * | 2010-06-28 | 2010-10-13 | 贾会平 | Beam limekiln |
| CN215627653U (en) * | 2021-09-26 | 2022-01-25 | 大峘集团有限公司 | Low-calorific-value fuel flue gas system suitable for double-hearth kiln |
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- 2023-03-16 CN CN202310252247.1A patent/CN116217099A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101857383A (en) * | 2010-06-28 | 2010-10-13 | 贾会平 | Beam limekiln |
| CN215627653U (en) * | 2021-09-26 | 2022-01-25 | 大峘集团有限公司 | Low-calorific-value fuel flue gas system suitable for double-hearth kiln |
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