Low-nitrogen energy-saving calcining system of high-activity lime based on hot carbon reduction technology

Abstract

The application provides a low-nitrogen energy-saving calcining system of high-activity lime based on a hot carbon reduction technology, and belongs to the technical field of lime production. Specifically, the low-nitrogen energy-saving calcining system comprises a multistage suspension preheating unit, a suspension low-nitrogen combustion unit and a fluidized bed suspension cooling unit. The fluidized bed suspension cooling unit comprises a fluidized bed suspension cooling furnace and two parallelly arranged cooling cyclones. The fluidized bed suspension cooling furnace is used for receiving materials after combustion in a decomposing furnace and gas-solid separation in a cyclone for cooling. The two parallelly arranged cooling cyclones are used for carrying out gas-solid separation on the materials cooled in the fluidized bed suspension cooling furnace, so that the materials are stored or transported to a finished product warehouse. In the application, two parallelly arranged cyclones are arranged in the cooling unit for single-stage gas-solid separation. The cooled materials only need to pass through one of the cooling cyclones to complete the separation, which greatly reduces the operation resistance of the system, reduces the power consumption and further reduces the cost.

Description

Technical Field

[0001] This application relates to the field of lime production technology, and more specifically, to a low-nitrogen, energy-saving calcination system for highly active lime based on thermal carbon reduction technology. Background Technology

[0002] Currently, domestic lime calcination systems mainly use vertical kilns and rotary kilns, employing lumpy limestone as raw material. The lumpy limestone is crushed to a suitable particle size for preheating and calcination. The calcined limestone decomposes into quicklime, which then needs to be cooled before storage and transportation. Existing cooling structures typically employ multi-stage suspension cooling systems, which include multiple sets of cyclones connected in series. The calcined quicklime passes through each cyclone for separation and cooling. While multi-stage cyclones allow for more thorough separation and cooling of the quicklime, they also increase system resistance, leading to increased power consumption and higher costs. Utility Model Content

[0003] The purpose of this application is to provide a low-nitrogen, energy-saving calcination system for highly active lime based on thermal carbon reduction technology, aiming to solve the problem in related technologies where the series connection of multiple cyclones in the cooling structure increases system resistance, leading to increased power consumption and higher costs.

[0004] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description or may be learned by practice of this application.

[0005] According to a first aspect of this application, a low-NOx energy-saving calcination system for highly active lime based on thermal carbon reduction technology is provided, comprising: a multi-stage suspension preheating unit, a suspension low-NOx combustion unit, and a fluidized bed suspension cooling unit;

[0006] The multi-stage suspension preheating unit is used for suspension preheating of materials;

[0007] The suspended low-NOx combustion unit includes a decomposition furnace, which is used to receive the material preheated by the multi-stage suspension preheating unit.

[0008] The fluidized bed suspension cooling unit includes a fluidized bed suspension cooling furnace and two parallel cooling cyclones. The fluidized bed suspension cooling furnace is used to receive the material after calcination in the decomposition furnace and cool the material. The two parallel cooling cyclones are used to cool and separate the material after it has been cooled by the fluidized bed suspension cooling furnace.

[0009] In one exemplary embodiment of this application, the material outlet at the bottom of the decomposition furnace is connected to the fluidized bed suspension cooling furnace.

[0010] In one exemplary embodiment of this application, a fluidizing blower is further included, which is connected to the gas inlet of the fluidized bed suspension cooling furnace, and the gas outlet of the cooling cyclone is connected to the gas inlet of the decomposition furnace. The gas entering the decomposition furnace from the cooling cyclone is a combustion-supporting gas.

[0011] In one exemplary embodiment of this application, the material preheated by the multi-stage suspension preheating unit enters the decomposition furnace in two separate streams;

[0012] The material in the decomposition furnace is distributed in two layers, with the upper layer accounting for 50%-90% and the lower layer accounting for 10%-50%.

[0013] In one exemplary embodiment of this application, the decomposition furnace is divided into a lower thermal carbon reduction zone and an upper combustion decomposition zone;

[0014] The combustion-supporting gas includes upper combustion-supporting air and lower combustion-supporting air. The distribution ratio of upper combustion-supporting air in the decomposition furnace is 50%-90%, and the distribution ratio of lower combustion-supporting air is 10%-50%.

[0015] The upper layer of fuel in the decomposition furnace has a distribution ratio of 50%-90%, and the lower layer has a distribution ratio of 10%-50%.

[0016] In one exemplary embodiment of this application, the gas outlet of the cooling cyclone and the gas inlet of the decomposition furnace are connected to a gas path that is divided into upper and lower paths, which correspond to the lower thermal carbon reduction zone and the upper combustion decomposition zone in the decomposition furnace, respectively.

[0017] In one exemplary embodiment of this application, both the upper and lower gas paths are equipped with gate valves to control the proportion of combustion air flowing into the lower hot carbon reduction zone and the upper combustion decomposition zone.

[0018] In one exemplary embodiment of this application, both the decomposition furnace and the fluidized bed suspension cooling furnace are provided with a central constriction structure to create a jetting effect;

[0019] The inlet of the fuel mill on the decomposition furnace is located at the constriction structure.

[0020] In one exemplary embodiment of this application, a high-temperature fan is also included. The outlet of the high-temperature fan is connected to the raw material mill and the fuel mill, and the inlet of the high-temperature fan is connected to the multi-stage suspension preheating unit. The gas that has undergone heat exchange in the multi-stage suspension preheating unit is introduced into the raw material mill and the fuel mill for preheating through the high-temperature fan.

[0021] The exemplary embodiments of this application may have some or all of the following beneficial effects:

[0022] The low-NOx energy-saving calcination system for highly active lime based on thermal carbon reduction technology provided in the example embodiment of this application includes a multi-stage suspension preheating unit, a suspension low-NOx combustion unit, and a fluidized bed suspension cooling unit. The suspension low-NOx combustion unit includes a decomposition furnace, which is connected to the cyclone separator in the multi-stage suspension preheating unit. The decomposition furnace receives material conveyed from the cyclone separator. The fluidized bed suspension cooling unit includes a fluidized bed suspension cooling furnace and two parallel cooling cyclones. The fluidized bed suspension cooling furnace receives and cools the material after combustion in the decomposition furnace and subsequent gas-solid separation in the cyclone separator. The two parallel cooling cyclones perform gas-solid separation on the material cooled by the fluidized bed suspension cooling furnace for storage or transportation to a finished product warehouse. In this application, two parallel cyclones are set in the cooling unit for single-stage gas-solid separation. The cooled material only needs to pass through one of the cooling cyclones to complete the separation, greatly reducing the system's operating resistance, reducing power consumption, and thus reducing costs.

[0023] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0024] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. It is obvious that the drawings described below are merely some embodiments of this application, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0025] Figure 1 A schematic diagram of the structure of a low-nitrogen, energy-saving calcination system for highly active lime based on thermal carbon reduction technology is shown in an embodiment of this application.

[0026] Explanation of reference numerals in the attached figures:

[0027] 1. Primary cyclone separator; 1-1. First flap valve; 1-2. Second flap valve; 2. Secondary cyclone separator; 2-1. Third flap valve; 3. Tertiary cyclone separator; 3-1. Fourth flap valve; 4. Quaternary cyclone separator; 4-1. Fifth flap valve; 4-2. Distributor valve; 4-3. Sixth flap valve; 4-4. Seventh flap valve; 5. Fifth cyclone separator; 5-1. Eighth flap valve; 6. Decomposition furnace; 6-1. Gate valve; 7. Fluidized bed suspension cooling furnace; 8. Cooling cyclone separator; 8-1. Ninth flap valve; 10. Fluidized air blower; 11. Finished product conveyor; 12. Finished product silo; 13. High-temperature blower; 14. Raw material mill; 15. Fuel mill; 16. Raw material silo; 17. Multi-stage suspension preheating unit; 18. Fluidized bed suspension cooling unit; 19. Suspension low-NOx combustion unit. Detailed Implementation

[0028] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this application will be thorough and complete, and will fully convey the concept of the exemplary embodiments to those skilled in the art. The same reference numerals in the drawings denote the same or similar structures, and therefore their detailed descriptions will be omitted. Furthermore, the drawings are merely illustrative of this application and are not necessarily drawn to scale.

[0029] Although relative terms such as "upper" and "lower" are used in this specification to describe the relative relationship of one component of an icon to another, these terms are used only for convenience, such as according to the orientation of the examples in the accompanying drawings. It is understood that if the device of the icon is flipped so that it is upside down, the component described as "upper" will become the component described as "lower." When a structure is "upper" of another structure, it may mean that the structure is integrally formed on the other structure, or that the structure is "directly" mounted on the other structure, or that the structure is "indirectly" mounted on the other structure through another structure.

[0030] The terms “a,” “one,” “the,” and “at least one” are used to indicate the existence of one or more elements / components / etc.; the terms “including” and “having” are used to indicate an open-ended inclusion and to mean that there may be other elements / components / etc. in addition to the listed elements / components / etc.; the terms “first” and “second” are used only as markers and are not a limitation on the number of objects.

[0031] Example

[0032] This embodiment provides a specific implementation of a low-nitrogen, energy-saving calcination system for highly active lime based on thermal carbon reduction technology, such as... Figure 1 As shown, the system includes a multi-stage suspension preheating unit 17, a suspension low-NOx combustion unit 19, and a fluidized bed suspension cooling unit 18. The suspension low-NOx combustion unit 19 includes a decomposition furnace 6, which is connected to the cyclone separator in the multi-stage suspension preheating unit 17. The decomposition furnace 6 is used to receive materials conveyed from the cyclone separator. The fluidized bed suspension cooling unit 18 includes a fluidized bed suspension cooling furnace 7 and two parallel cooling cyclones 8. The fluidized bed suspension cooling furnace 7 is used to receive and cool the material after combustion in the decomposition furnace 6 and gas-solid separation in the cyclone separator. The two parallel cooling cyclones 8 are used to perform gas-solid separation on the material cooled by the fluidized bed suspension cooling furnace 7 for storage or transportation to the finished product warehouse 12.

[0033] In this application, two parallel cyclones are set in the cooling unit for single-stage gas-solid separation. The cooled material only needs to pass through one of the cooling cyclones 8 to complete the separation, which greatly reduces the system's operating resistance, power consumption, and thus cost. The two parallel cooling cyclones 8 reduce the system's operating resistance while meeting separation efficiency requirements. In this application, the fluidized bed suspension cooling furnace 7 can receive the material separated by the end cyclones and cool it. During the cooling process, cold air enters the fluidized bed suspension cooling furnace 7, mixes with the material for heat exchange, and lowers the material's temperature. The fully mixed material and cold air enter the cooling cyclone 8 for further heat exchange and simultaneous gas-solid separation. The material separated in the cooling cyclone 8 is the finished product, which can be used for storage and transportation. The cold air enters from the bottom of the fluidized bed suspension cooling furnace 7 and flows upward. During the upward flow, it mixes with the material and carries the material upward, finally carrying it into the cooling cyclone 8 for gas-solid separation.

[0034] In this embodiment, the multi-stage suspension preheating unit 17 includes multiple interconnected cyclones. Specifically, the multi-stage suspension preheating unit 17 includes a primary cyclone 1, a secondary cyclone 2, a tertiary cyclone 3, a quaternary cyclone 4, and a quinary cyclone 5. The high-temperature fan 13 is connected to the primary cyclone 1, and the inlet of the primary cyclone 1 is connected to the raw material silo 16. A first connecting duct is provided between the inlet of the primary cyclone 1 and the inlet of the secondary cyclone 2, and a second connecting duct is provided between the inlet of the secondary cyclone 2 and the inlet of the tertiary cyclone 3. A third connecting duct is provided between the inlet of the fourth-stage cyclone 4 and the inlet of the fifth-stage cyclone 5. A fourth connecting duct is provided between the inlet of the fourth-stage cyclone 4 and the inlet of the fifth-stage cyclone 5. The outlet of the first-stage cyclone 1 and the second connecting duct, the outlet of the second-stage cyclone 2 and the third connecting duct, and the outlet of the third-stage cyclone 3 and the fourth connecting duct are connected via material pipelines. The outlet of the fifth-stage cyclone 5 is connected to the fluidized bed suspension cooling furnace 7. The outlet of the fourth-stage cyclone 4 is connected to the material inlet of the decomposition furnace 6. The inlet of the fifth-stage cyclone 5 is connected to the material outlet at the top of the decomposition furnace 6.

[0035] The material conveying process is as follows: Material in raw material silo 16 enters the primary cyclone separator 1 through the first connecting duct. During conveying in the first connecting duct, material undergoes gas-air heat exchange, and is carried by the airflow into the primary cyclone separator 1 for gas-solid separation. After separation, the material enters the second connecting duct between the tertiary cyclone separator 3 and the secondary cyclone separator 2 for further gas-air heat exchange, and is then carried by the airflow into the secondary cyclone separator 2 for gas-solid separation. Finally, after separation, the material enters the third connecting duct between the quaternary cyclone separator 4 and the tertiary cyclone separator 3 for further gas-air heat exchange, and is then carried by the airflow into the tertiary cyclone separator 3. Gas-solid separation occurs in cylinder 3. The separated material enters the fourth connecting duct between the five-stage cyclone separator 5 and the four-stage cyclone separator 4 for gas-material heat exchange, and is then carried into the four-stage cyclone separator 4 for further gas-solid separation. The separated material then enters the decomposition furnace 6, where it is calcined and decomposed. The decomposed material is divided into two paths: one path enters the five-stage cyclone separator 5 with the rising airflow and, after separation, enters the fluidized bed suspension cooling furnace 7; the other path (such as larger particles, coal gangue, etc.) settles to the bottom of the decomposition furnace 6 and then enters the fluidized bed suspension cooling furnace 7. The material passes through a multi-stage suspension preheating unit 17 before entering the decomposition furnace 6, which pre-heats the material and reduces the calcination time in the decomposition furnace 6.

[0036] In this embodiment, a fluidizing blower 10 is also included. The outlet of the fluidizing blower 10 is connected to the fluidized bed suspension cooling furnace 7. The connection point between the fluidizing blower 10 and the fluidized bed suspension cooling furnace 7 is lower than the connection points between the five-stage cyclone separator 5 and the decomposition furnace 6 and the fluidized bed suspension cooling furnace 7. That is, the connection point between the fluidizing blower 10 and the fluidized bed suspension cooling furnace 7 is located at the bottom of the fluidized bed suspension cooling furnace 7, allowing air to move upward from the bottom of the fluidized bed suspension cooling furnace 7, so that the material is in a suspended fluidized state in the fluidized bed suspension cooling furnace 7. In the fluidized bed suspension cooling furnace 7, gas-solid heat exchange is performed. The heated gas flow enters the parallel-connected cooling cyclone 8 from the top of the furnace for gas-solid separation. The hot gas, acting as combustion air, enters the decomposition furnace 6 through two separate paths. The flue gas generated in the material decomposition furnace 6 enters the multi-stage suspension preheating unit 17 from the top of the decomposition furnace 6. The flue gas exiting from the first-stage cyclone 1 serves as a drying heat source and enters the raw material mill 14 and fuel mill 15 respectively via the high-temperature fan 13. The material exiting from the outlet of the cooling cyclone 8 is the finished product, which is stored or transported to the finished product warehouse 12. Simultaneously, placing the inlet of the fluidizing fan 10 at the bottom of the fluidized bed suspension cooling furnace 7 helps prevent material collapse. The fluidizing fan 10 blows air upwards from the bottom of the fluidized bed suspension cooling furnace 7, preventing material accumulation at the bottom of the furnace.

[0037] In this embodiment, a high-temperature fan 13 is also included. The high-temperature fan 13 is connected to the outlet of the first-stage cyclone 1. The extraction by the high-temperature fan 13 makes the cyclone in the multi-stage suspension preheating unit 17 under negative pressure. The outlet of the high-temperature fan 13 can also be connected to the raw material mill 14 and the fuel mill 15. The hot gas blown out by the high-temperature fan 13 can be used to preheat the raw material mill 14 and the fuel mill 15.

[0038] The high-temperature fan 13 is connected to the first-stage cyclone 1 in the multi-stage suspension preheating unit 17. The high-temperature fan 13 is used to draw hot air flowing from the fluidized bed suspension cooling unit 18, the suspension low-NOx combustion unit 19, and the multi-stage suspension preheating unit 17, so that the hot air in the system is discharged from the combustion cooling section after passing through the multi-stage suspension preheating unit 17. During the process of material being transported from the multi-stage suspension preheating unit 17 to the suspension low-NOx combustion unit 19, it first exchanges heat with the hot air to complete the preheating, so that the material has a certain temperature when it enters the suspension low-NOx combustion unit 19, reducing the heating time of the material by the suspension low-NOx combustion unit 19. The fuel mill 15 is used to transport fuel to the decomposition furnace 6. Only after the fuel is transported can the material in the decomposition furnace 6 be calcined. The raw material mill 14 is used to provide material to the raw material silo 16. The raw material silo 16 is connected to the multi-stage suspension preheating unit 17, and the material is transported from the raw material silo 16 to the multi-stage suspension preheating unit 17. The finished product silo 12 is used to receive the finished material after it has been cooled by the cooling cyclone 8.

[0039] In this embodiment, the material separated from the four-stage cyclone 4 enters the decomposition furnace 6 in two separate streams. The material is distributed in two layers in the decomposition furnace 6, with the upper layer accounting for 50%-90% and the lower layer accounting for 10%-50%. Furthermore, a lower thermal carbon reduction zone and an upper combustion decomposition zone are formed in the decomposition furnace 6. The distribution ratio of combustion air in the upper layer of the decomposition furnace 6 is 50%-90%, and the distribution ratio of combustion air in the lower layer is 10%-50%. The distribution ratio of fuel in the upper layer of the decomposition furnace 6 is 50%-90%, and the distribution ratio of fuel in the lower layer is 10%-50%. Through the different proportions of materials, combustion air, and fuel in the upper and lower layers, a lower thermal carbon reduction zone and an upper combustion decomposition zone are formed in the decomposition furnace 6. If there is more combustion air and fuel in the upper layer of the decomposition furnace 6, the material is fully combusted, forming the upper combustion decomposition zone. Conversely, if there is more material in the lower layer of the decomposition furnace 6 and less combustion air and fuel, the material is not fully combusted, resulting in a reduction reaction. This causes most of the NOx produced by the fuel to react with CO in the reduction zone to become N2 and CO2, forming the lower thermal carbon reduction zone.

[0040] Furthermore, the combustion decomposition zone is a concentrated heat release area. Adding materials to this zone can absorb heat and balance the temperature, keeping it stably controlled at 900-1000℃. For example, when the temperature is high, the amount of material entering the zone is increased, and when the temperature is low, the amount of material entering the zone is reduced to avoid generating more thermal nitrogen oxides. By controlling the temperature within this zone, limestone can be completely decomposed into lime (CaO) without the lime being over-burned into dead lime (lime calcined at temperatures above 1100℃). The generated fuel-type nitrogen oxides are suppressed and reduced by adding pulverized coal to the lower thermal carbon reduction zone. Unburned pulverized coal is ensured to burn completely by supplementing combustion air in the upper combustion decomposition zone.

[0041] In this embodiment, both the decomposition furnace 6 and the fluidized bed suspension cooling furnace 7 are equipped with a central constriction structure to create a jetting effect. When materials and fuel pass through the central constriction structure, the airflow velocity suddenly increases and the pressure changes, forming strong turbulence and mixing phenomena, avoiding laminar flow, and facilitating the full dispersion, mixing, and combustion of materials and fuel. Furthermore, the inlet of the fuel mill 15 on the decomposition furnace 6 is located at the constriction structure. Due to the limited space in the decomposition furnace 6, placing the fuel inlet at the constriction structure allows for greater dispersion of fuel upon entering the decomposition furnace 6. The increased airflow velocity at the central constriction structure position enables rapid fuel dispersion and combustion. Simultaneously, the fuel mill 15 enters the decomposition furnace 6 through two paths, upper and lower, preventing fuel accumulation in the decomposition furnace 6. This dual entry reduces fuel accumulation, accelerates the mixing of fuel and materials, and speeds up the combustion rate.

[0042] Furthermore, the central constriction structure is provided in multiple locations within the furnace, allowing a jetting effect to be generated at multiple locations within the furnace.

[0043] Furthermore, the outlet of the high-temperature fan 13 is connected to the raw material mill 14 and the fuel mill 15, so that the flue gas drawn from the primary cyclone 1 can be used as a drying heat source and transported to the raw material mill 14 and the fuel mill 15 to heat the materials and fuel respectively.

[0044] In this embodiment, the fuel provided by the fuel mill 15 is pulverized coal. Of course, other fuels besides pulverized coal can also be selected, as long as the overall structure and process flow are not affected.

[0045] In this embodiment, the cooling cyclone 8 is connected to the upper hot carbon reduction zone and the lower combustion decomposition zone of the decomposition furnace 6 through connecting pipes, and gate valves are provided on the connecting pipes. By controlling the gate valves, the amount of combustion air delivered from the cooling cyclone 8 to the decomposition furnace 6 can be controlled so that the proportion of combustion air in the decomposition furnace 6 can meet the proportion of the lower combustion decomposition zone and the upper hot carbon reduction zone.

[0046] Furthermore, the cooling cyclone 8 can remove the heat from the hot air after heat exchange. The combustion air used in the decomposition furnace 6 does not come from the cold air in the atmosphere. After being separated by the five-stage cyclone 5, the heat of the high-temperature lime entering the cooling furnace is cooled by the fluidized bed suspension cooling furnace 7. Almost all the heat is carried away by the air entering the cooling cyclone 8. This not only heats the air needed for coal combustion in the calcining furnace, thus saving coal, but also rapidly cools the high-temperature lime brought by the five-stage cyclone 5, making it easier to store, transport and use.

[0047] In this embodiment, the primary cyclone 1 consists of two cyclone ducts arranged side by side, and each cyclone duct is equipped with a flap valve between itself and the tertiary cyclone 3, namely the first flap valve 1-1 and the second flap valve 1-2; the secondary cyclone 2 is equipped with a third flap valve 2-1 between itself and the four-stage cyclone duct; the tertiary cyclone 3 and the quinary cyclone 5 are equipped with a fourth flap valve 3-1; the quinary cyclone 4 and the decomposition furnace 6 are connected by a material distribution valve 4-2, which divides the material into two paths to enter the decomposition furnace 6; the quinary cyclone 4 and the material distribution valve 4-2 are equipped with a fifth flap valve 4-1; the material distribution valve 4-2 and the decomposition furnace 6 are equipped with a sixth flap valve 4-3 and a seventh flap valve 4-4, respectively; and the quinary cyclone 5 and the fluidized bed suspension cooling furnace 7 are equipped with an eighth flap valve 5-1.

[0048] In this embodiment, the cooling cyclone 8 is connected to the finished product conveyor 11. After the finished product material comes out of the cooling cyclone 8, it is transported to the finished product warehouse 12 by the finished product conveyor 11. A ninth flap valve 8-1 is provided between the two cooling cyclones 8 and the finished product conveyor 11.

[0049] Working principle:

[0050] During the operation of this system, the material flow, fuel flow, and airflow direction are observed.

[0051] Material flow: The material in raw material silo 16 enters the primary cyclone separator 1 through connecting pipes. During the material transport process through the connecting pipes, material-gas heat exchange occurs, and the material is carried by the airflow into the primary cyclone separator 1 for gas-solid separation. The separated material enters the connecting pipe between the tertiary cyclone separator 3 and the secondary cyclone separator 2 for material-gas heat exchange, and is then carried by the airflow into the secondary cyclone separator 2 for gas-solid separation. The separated material enters the connecting pipe between the quaternary cyclone separator 4 and the tertiary cyclone separator 3 for material-gas heat exchange, and is then carried by the airflow into the tertiary cyclone separator 3 for gas-solid separation. The separated material then enters the quinary cyclone separator 5... After heat exchange between the material and gas in the connecting pipe of the fourth-stage cyclone 4, the material is carried into the fourth-stage cyclone 4 for gas-solid separation. The separated material enters the decomposition furnace 6, where it is calcined and decomposed. The decomposed material is divided into two paths: one path enters the fifth-stage cyclone 5 with the rising airflow and, after separation, enters the fluidized bed suspension cooling furnace 7; the other path sinks to the bottom of the decomposition furnace 6 and enters the fluidized bed suspension cooling furnace 7. After thorough mixing and heat exchange with the cold air in the fluidized bed suspension cooling furnace 7, the material is suspended and rises to two parallel cooling cyclones 8, where it is separated and collected as finished product material.

[0052] Fuel flow: Fuel from fuel mill 15 is fed into decomposition furnace 6 via pneumatic conveying pipeline, and the burners are distributed in multiple layers and at multiple points.

[0053] Airflow direction: Under the suction of the high-temperature fan 13, the system from the inlet of the high-temperature fan 13 to the fluidized bed suspension cooling furnace 7 is under negative pressure. Most of the required cooling air enters horizontally from the bottom of the fluidized bed suspension cooling furnace 7, while the bottom is supplied by the fluidizing fan 10, so that the material is in a suspended fluidized state in the furnace for gas-solid heat exchange. The heated airflow enters from the top of the fluidized bed suspension cooling furnace 7 into two parallel cooling cyclones 8 for gas-solid separation. The hot gas is used as combustion air and enters the lower part of the decomposition furnace 6 in two paths. The flue gas generated by the calcination and decomposition of the material in the decomposition furnace 6 enters the multi-stage suspension preheating unit 17 from the top of the decomposition furnace 6. The flue gas coming out of the first-stage cyclone 1 is used as a drying heat source and enters the raw material mill 14 and the fuel mill 15 respectively.

[0054] Other embodiments of this application will readily conceive of by those skilled in the art upon consideration of the specification and practice of the embodiments thereof. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not claimed in this application. The specification and embodiments are to be considered exemplary only, and the true scope and spirit of this application are indicated by the appended claims.

Claims

1. A low-nitrogen, energy-saving calcination system for highly active lime based on thermal carbon reduction technology, characterized in that, include: Multi-stage suspension preheating unit, suspension low-NOx combustion unit, fluidized bed suspension cooling unit; The multi-stage suspension preheating unit is used for suspension preheating of materials; The suspended low-NOx combustion unit includes a decomposition furnace, which is used to receive the material preheated by the multi-stage suspension preheating unit. The fluidized bed suspension cooling unit includes a fluidized bed suspension cooling furnace and two parallel cooling cyclones. The fluidized bed suspension cooling furnace is used to receive the material after calcination in the decomposition furnace and cool the material. The two parallel cooling cyclones are used to cool and separate the material after it has been cooled by the fluidized bed suspension cooling furnace.

2. The low-nitrogen, energy-saving calcination system for highly active lime based on thermal carbon reduction technology according to claim 1, characterized in that, The material outlet at the bottom of the decomposition furnace is connected to the fluidized bed suspension cooling furnace.

3. The low-nitrogen, energy-saving calcination system for highly active lime based on thermal carbon reduction technology according to claim 2, characterized in that, It also includes a fluidizing blower, which is connected to the gas inlet of the fluidized bed suspension cooling furnace, and the gas outlet of the cooling cyclone is connected to the gas inlet of the decomposition furnace. The gas entering the decomposition furnace from the cooling cyclone is a combustion-supporting gas.

4. The low-nitrogen, energy-saving calcination system for highly active lime based on thermal carbon reduction technology according to claim 3, characterized in that, The material preheated by the multi-stage suspension preheating unit is divided into two streams and enters the decomposition furnace. The material in the decomposition furnace is distributed in two layers, with the upper layer accounting for 50%-90% and the lower layer accounting for 10%-50%.

5. The low-nitrogen, energy-saving calcination system for highly active lime based on thermal carbon reduction technology according to claim 4, characterized in that, The decomposition furnace is divided into a lower hot carbon reduction zone and an upper combustion decomposition zone. The combustion-supporting gas includes upper combustion-supporting air and lower combustion-supporting air. The distribution ratio of upper combustion-supporting air in the decomposition furnace is 50%-90%, and the distribution ratio of lower combustion-supporting air is 10%-50%. The upper layer of fuel in the decomposition furnace has a distribution ratio of 50%-90%, and the lower layer has a distribution ratio of 10%-50%.

6. The low-nitrogen, energy-saving calcination system for highly active lime based on thermal carbon reduction technology according to claim 5, characterized in that, The gas outlet of the cooling cyclone and the gas inlet of the decomposition furnace are connected to two gas paths, one upper and one lower, which correspond to the lower thermal carbon reduction zone and the upper combustion decomposition zone in the decomposition furnace, respectively.

7. The low-nitrogen, energy-saving calcination system for highly active lime based on thermal carbon reduction technology according to claim 6, characterized in that, Both the upper and lower gas lines are equipped with gate valves to control the proportion of combustion air flowing into the lower hot carbon reduction zone and the upper combustion decomposition zone.

8. The low-nitrogen, energy-saving calcination system for highly active lime based on thermal carbon reduction technology according to claim 3, characterized in that, Both the decomposition furnace and the fluidized bed suspension cooling furnace are equipped with a central constriction structure to create a jetting effect; The decomposition furnace is connected to a fuel mill, and the inlet of the fuel mill on the decomposition furnace is located at the constriction structure.

9. The low-nitrogen, energy-saving calcination system for highly active lime based on thermal carbon reduction technology according to claim 1, characterized in that, It also includes a high-temperature fan, the outlet of which is connected to the raw material mill and the fuel mill, and the inlet of which is connected to the multi-stage suspension preheating unit. The high-temperature fan is used to pass the gas that has undergone heat exchange in the multi-stage suspension preheating unit into the raw material mill and the fuel mill for preheating.

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