High-activity lime low-nitrogen energy-saving calcining system based on thermal carbon reduction technology
By introducing a multi-stage suspended preheating unit, a suspended low-nitrogen combustion unit and a fluidized bed suspended cooling unit into the lime calcining system, the problem of high power consumption caused by multi-stage cyclones was solved, low-nitrogen energy-saving calcination was achieved, costs were reduced and the activity of the lime was improved.
Patent Information
- Application Number
- CN202510968092.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-14
- Publication Date
- 2025-09-30
AI Technical Summary
In existing lime calcining systems, the installation of multiple cyclones in the cooling structure increases system resistance, resulting in high power consumption and costs.
The multi-stage suspension preheating unit, suspension low-nitrogen combustion unit and fluidized bed suspension cooling unit are adopted. Through multiple groups of connected cyclones and parallel cooling cyclones, suspension preheating, low-nitrogen combustion and suspension cooling of materials are achieved, the number of cyclone stages is reduced, and the system resistance is lowered.
It reduces the operating resistance of the system, reduces power consumption, and thus reduces costs, while improving the activity and production efficiency of lime.
Smart Images
Figure CN120720864A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of lime production, and in particular to a low-nitrogen energy-saving calcination system for high-activity lime based on thermal carbon reduction technology. Background Art
[0002] Currently, domestic lime calcining systems are primarily based on vertical kilns and rotary kilns. The raw material is lump limestone, which is crushed to an appropriate particle size for preheating and calcination. The calcined limestone then decomposes into quicklime, which then needs to be cooled before storage and transportation. Existing cooling structures typically utilize a multi-stage suspension cooling system, which consists of multiple sets of cyclones arranged in series. The calcined quicklime passes through each cyclone for separation and cooling. While this multi-stage cyclone configuration allows for more thorough separation and cooling of the quicklime, it increases system resistance, resulting in increased power consumption and higher costs. Summary of the Invention
[0003] The purpose of this application is to provide a low-nitrogen energy-saving calcination system for high-activity lime based on thermal carbon reduction technology, aiming to solve the problem in the related art that the multi-stage cyclone tubes arranged in series in the cooling structure increase the system resistance, resulting in increased power consumption and higher costs.
[0004] Additional aspects and advantages of the present 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 the present application.
[0005] According to a first aspect of the present application, a low-nitrogen energy-saving calcination system for high-activity lime based on thermal carbon reduction technology is provided, comprising: Multi-stage suspension preheating unit, suspension low-nitrogen combustion unit, fluidized bed suspension cooling unit; The multi-stage suspension preheating unit is used to suspend and preheat the material, and the multi-stage suspension preheating unit includes multiple groups of connected cyclones; The suspended low-nitrogen combustion unit includes a decomposition furnace, which is connected to the cyclone in the multi-stage suspended preheating unit and is used to receive the preheated material transported from the cyclone; The cyclone at the end of the plurality of cyclone groups is used to receive the material after combustion and decomposition in the decomposition furnace and perform gas-solid separation on the material; The fluidized bed suspension cooling unit includes a fluidized bed suspension cooling furnace and two cooling cyclones arranged in parallel. The fluidized bed suspension cooling furnace is used to receive the material separated by the terminal cyclone and cool the material. The two cooling cyclones arranged in parallel are used to cool and separate the gas and solid of the material after being cooled by the fluidized bed suspension cooling furnace.
[0006] In an exemplary embodiment of the present application, the multi-stage suspension preheating unit includes a first-stage cyclone, a second-stage cyclone, a third-stage cyclone, a fourth-stage cyclone, and a fifth-stage cyclone, wherein the fifth-stage cyclone is the terminal cyclone. A first connecting air duct is provided between the inlet of the first-stage cyclone and the inlet of the second-stage cyclone, and the first connecting air duct is used to receive materials transmitted from the raw material warehouse. A second connecting air duct is provided between the inlet of the second-stage cyclone and the inlet of the third-stage cyclone, a third connecting air duct is provided between the inlet of the third-stage cyclone and the inlet of the fourth-stage cyclone, and a fourth connecting air duct is connected between the inlet of the fourth-stage cyclone and the inlet of the fifth-stage cyclone. The outlet of the first-stage cyclone is connected to the second connecting air duct, the outlet of the second-stage cyclone is connected to the third connecting air duct, and the outlet of the third-stage cyclone is connected to the fourth connecting air duct through a material pipeline. The outlet of the fifth-stage cyclone is connected to the fluidized bed suspension cooling furnace, the outlet of the fourth-stage cyclone is connected to the material inlet of the decomposition furnace, and the inlet of the fifth-stage cyclone is connected to the material outlet at the top of the decomposition furnace.
[0007] In an exemplary embodiment of the present application, the material outlet at the bottom of the decomposition furnace is connected to the fluidized bed suspension cooling furnace.
[0008] In an exemplary embodiment of the present application, a fluidizing fan 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.
[0009] In an exemplary embodiment of the present application, the materials separated from the four-stage cyclone enter the decomposition furnace in two ways; The materials in the decomposition furnace are distributed in two layers, the upper layer accounts for 50%-90% and the lower layer accounts for 10%-50%.
[0010] In an exemplary embodiment of the present application, the decomposition furnace is divided into a lower combustion decomposition zone and an upper hot carbon reduction zone; The combustion-supporting gas includes an upper layer of combustion-supporting air and a lower layer of combustion-supporting air. The distribution ratio of the upper layer of combustion-supporting air in the decomposition furnace is 50%-90%, and the distribution ratio of the lower layer of combustion-supporting air is 10%-50%. The distribution ratio of the upper layer fuel in the decomposition furnace is 50%-90%, and the distribution ratio of the lower layer fuel is 10%-50%.
[0011] In an exemplary embodiment of the present application, the gas path connecting the gas outlet of the cooling cyclone and the gas inlet of the decomposition furnace is divided into two paths, the upper and lower gas paths corresponding to the lower hot carbon reduction zone and the upper combustion decomposition zone in the decomposition furnace respectively.
[0012] In an exemplary embodiment of the present application, gate valves are provided on both the upper and lower gas lines to control the ratio of combustion-supporting air flowing into the lower hot carbon reduction zone and the upper combustion decomposition zone.
[0013] In an exemplary embodiment of the present application, the decomposition furnace and the fluidized bed suspension cooling furnace are both provided with a constriction structure in the middle to form a gushing effect; The inlet position of the fuel mill provided on the decomposition furnace is provided at the necking structure.
[0014] In an exemplary embodiment of the present application, a high-temperature fan is further 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 cyclone located at the head end of the multiple groups of cyclones. The gas in the cyclone that has undergone heat exchange is passed into the raw material mill and the fuel mill through the high-temperature fan for preheating.
[0015] The exemplary embodiments of the present application may have some or all of the following beneficial effects: The low-nitrogen energy-saving calcination system of high-activity lime based on thermal carbon reduction technology provided in the example embodiment of the present application includes a multi-stage suspension preheating unit, a suspension low-nitrogen combustion unit, and a fluidized bed suspension cooling unit, wherein the multi-stage suspension preheating unit includes multiple groups of cyclones connected by connecting pipes; the suspension low-nitrogen combustion unit includes a decomposition furnace, which is connected to the cyclones in the multi-stage suspension preheating unit, and the decomposition furnace is used to receive materials transported from the cyclones; the fluidized bed suspension cooling unit includes a fluidized bed suspension cooling furnace and two parallel-arranged cooling cyclones, the fluidized bed suspension cooling furnace is used to receive materials after combustion in the decomposition furnace and then gas-solid separation in the cyclones for cooling, and the two parallel-arranged cooling cyclones are used to perform gas-solid separation on the materials cooled by the fluidized bed suspension cooling furnace for storage or transportation to a finished product warehouse. In the present application, two parallel cyclones are arranged in the cooling unit to perform single-stage gas-solid separation, and the cooled material only needs to pass through one of the cooling cyclones to complete the separation, which greatly reduces the operating resistance of the system, reduces power consumption, and thus reduces costs.
[0016] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] The accompanying drawings are incorporated into and constitute a part of the specification, illustrate embodiments consistent with the present application, and together with the specification, are used to explain the principles of the present application. Obviously, the drawings described below are only some embodiments of the present application, and those skilled in the art can derive other drawings based on these drawings without inventive effort.
[0018] Figure 1 A schematic structural diagram of a low-nitrogen energy-saving calcination system for high-activity lime based on thermal carbon reduction technology in an embodiment of the present application is shown.
[0019] Description of reference numerals: 1. First-stage cyclone; 1-1. First flap valve; 1-2. Second flap valve; 2. Second-stage cyclone; 2-1. Third flap valve; 3. Third-stage cyclone; 3-1. Fourth flap valve; 4. Fourth-stage cyclone; 4-1. Fifth flap valve; 4-2. Dispensing valve; 4-3. Sixth flap valve; 4-4. Seventh flap valve; 5. Fifth-stage cyclone; 5-1. Eighth flap valve; 6. Decomposition furnace; 6-1. Gate valve; 7. Fluidized bed suspension cooling furnace; 8. Cooling cyclone; 8-1. Ninth flap valve; 10. Fluidizing fan; 11. Finished product conveyor; 12. Finished product warehouse; 13. High-temperature fan; 14. Raw material mill; 15. Fuel mill; 16. Raw material warehouse; 17. Multi-stage suspension preheating unit; 18. Fluidized bed suspension cooling unit; 19. Suspended low-nitrogen combustion unit. DETAILED DESCRIPTION
[0020] Example embodiments will now be described more fully with reference to the accompanying drawings. However, the example 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 concepts of the example embodiments to those skilled in the art. Like reference numerals in the figures represent like or similar structures, and thus their detailed descriptions will be omitted. Furthermore, the figures are merely schematic illustrations of the present application and are not necessarily drawn to scale.
[0021] While relative terms such as "upper" and "lower" are used in this specification to describe the relationship of one illustrated component to another, these terms are used for convenience only, such as in accordance with the orientation of the illustrations in the accompanying drawings. It should be understood that if the illustrated device were flipped upside down, the component described as "upper" would become the component "lower." When a structure is referred to as "on" another structure, this may mean that the structure is integrally formed with the other structure, that the structure is "directly" disposed on the other structure, or that the structure is "indirectly" disposed on the other structure through the other structure.
[0022] The terms "a", "an", "the" and "at least one" are used to indicate the presence of one or more elements / components / etc.; the terms "including" and "having" are used to express open-ended inclusion and mean that additional elements / components / etc. may be present in addition to the listed elements / components / etc.; the terms "first" and "second" are used only as labels and do not limit the quantity of their objects. Example
[0023] This embodiment provides a specific implementation method of a low-nitrogen energy-saving calcination system for high-activity lime based on thermal carbon reduction technology, such as Figure 1 As shown, it includes a multi-stage suspension preheating unit 17, a suspension low-nitrogen combustion unit 19, and a fluidized bed suspension cooling unit 18, wherein the multi-stage suspension preheating unit 17 includes a plurality of cyclones connected by connecting pipes; the suspension low-nitrogen combustion unit 19 includes a decomposition furnace 6, which is connected to the cyclones in the multi-stage suspension preheating unit 17, and the decomposition furnace 6 is used to receive materials transported from the cyclones; the fluidized bed suspension cooling unit 18 includes a fluidized bed suspension cooling furnace 7 and two cooling cyclones 8 arranged in parallel, the fluidized bed suspension cooling furnace 7 is used to receive and cool the materials after combustion in the decomposition furnace 6 and then gas-solid separation in the cyclones, and the two cooling cyclones 8 arranged in parallel are used to perform gas-solid separation on the materials cooled by the fluidized bed suspension cooling furnace 7 for storage or transportation to the finished product warehouse 12.
[0024] In this application, two parallel cyclones are set in the cooling unit to perform 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 operating resistance of the system, reduces power consumption, and thus reduces costs. The two parallel cooling cyclones 8 reduce the operating resistance of the system while meeting the separation efficiency. In this application, the fluidized bed suspension cooling furnace 7 can receive the material separated by the terminal cyclone and cool the material. During the cooling process, cold air enters the fluidized bed suspension cooling furnace 7, mixes with the material and undergoes heat exchange to reduce the temperature of the material. The fully mixed material and cold air enter the cooling cyclone 8 for further heat exchange and gas-solid separation. The material separated in the cooling cyclone 8 is the finished product and can be used for storage and transportation. The cold air enters from the bottom of the fluidized bed suspension cooling furnace 7 and flows from bottom to top. During the upward flow, it mixes with the material and drives the material upward, ultimately carrying the material into the cooling cyclone 8 for gas-solid separation.
[0025] In this embodiment, the multi-stage suspension preheating unit 17 includes a first-stage cyclone 1, a second-stage cyclone 2, a third-stage cyclone 3, a fourth-stage cyclone 4 and a fifth-stage cyclone 5. The high-temperature fan 13 is connected to the first-stage cyclone 1, and the inlet of the first-stage cyclone 1 is connected to the raw material storage 16. A first connecting air duct is provided between the inlet of the first-stage cyclone 1 and the inlet of the second-stage cyclone 2, a second connecting air duct is provided between the inlet of the second-stage cyclone 2 and the inlet of the third-stage cyclone 3, and a second connecting air duct is provided between the inlet of the third-stage cyclone 3 and the inlet of the fourth-stage cyclone 4. A third connecting air duct is provided, and a fourth connecting air duct is provided between the inlet of the fourth-stage cyclone 4 and the inlet of the fifth-stage cyclone 5. A material pipeline connects the outlet of the first-stage cyclone 1 to the second connecting air duct, the outlet of the second-stage cyclone 2 to the third connecting air duct, and the outlet of the third-stage cyclone 3 to the fourth connecting air duct. 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, and the inlet of the fifth-stage cyclone 5 is connected to the material outlet at the top of the decomposition furnace 6. The material conveying process is as follows: the material in the raw material warehouse 16 enters the first-level cyclone 1 through the first connecting air duct. During the material conveying process in the first connecting air duct, the material is heat exchanged with the gas, and the material is brought into the first-level cyclone 1 by the air flow for gas-solid separation; the separated material enters the third-level cyclone 3 and the second-level cyclone 2 in the second connecting air duct for material-gas heat exchange, and the material is brought into the second-level cyclone 2 by the air flow for gas-solid separation; the separated material enters the fourth-level cyclone 4 and the third-level cyclone 3 in the third connecting air duct for material-gas heat exchange, and the material is brought into the third-level cyclone Gas-solid separation occurs in cylinder 3. The separated material enters the fourth connecting duct from the fifth-stage cyclone 5 to the fourth-stage cyclone 4 for material-gas heat exchange. The material is then 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 follows the rising airflow into the fifth-stage cyclone 5, where it is separated and then enters the fluidized bed suspension cooling furnace 7. The other path (such as larger particles of material, coal gangue, etc.) settles to the bottom of the decomposition furnace 6 and enters the fluidized bed suspension cooling furnace 7. The material passes through the multi-stage suspension preheating unit 17 before entering the decomposition furnace 6, which can pre-raise the material temperature and reduce the calcination time in the decomposition furnace 6.
[0026] In this embodiment, a fluidizing fan 10 is also included. The outlet of the fluidizing fan 10 is connected to the fluidized bed suspension cooling furnace 7, and the connection position of the fluidizing fan 10 and the fluidized bed suspension cooling furnace 7 is lower than the connection position of the five-stage cyclone 5 and the decomposition furnace 6 and the fluidized bed suspension cooling furnace 7. That is, the connection position of the fluidizing fan 10 and the fluidized bed suspension cooling furnace 7 is located at the bottom of the fluidized bed suspension cooling furnace 7, so that the air can move upward from the bottom of the fluidized bed suspension cooling furnace 7, so that the material is suspended and fluidized in the fluidized bed suspension cooling furnace 7. The heated air flows from the furnace top into the parallel-connected cooling cyclone 8 for gas-solid separation. The hot gas then flows into the decomposition furnace 6 in two paths, one above and one below, as combustion air. 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 from the first-stage cyclone 1 is used as a drying heat source and enters the raw material mill 14 and the fuel mill 15 via the high-temperature fan 13. The material exiting the cooling cyclone 8 is the finished product and is stored or transported to the finished product warehouse 12. Furthermore, the inlet of the fluidizing fan 10 is located at the bottom of the fluidized bed suspension cooling furnace 7 to prevent material collapse. The fluidizing fan 10 blows air upward from the bottom of the fluidized bed suspension cooling furnace 7 to prevent material from accumulating at the bottom of the fluidized bed suspension cooling furnace 7.
[0027] In this embodiment, a high-temperature fan 13 is further included. The high-temperature fan 13 is connected to the outlet of the first-stage cyclone 1. The extraction of the high-temperature fan 13 causes the cyclones in the multi-stage suspension preheating unit 17 to be in a negative pressure state, and 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.
[0028] 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 extract hot air flowing through the fluidized bed suspension cooling unit 18, the suspension low-nitrogen 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 part after passing through the multi-stage suspension preheating unit 17. In the process of transporting the material from the multi-stage suspension preheating unit 17 to the suspension low-nitrogen combustion unit 19, the material first exchanges heat with the hot air to complete preheating, so that the material has a certain temperature when entering the suspension low-nitrogen combustion unit 19, thereby reducing the heating time of the material in the suspension low-nitrogen 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 warehouse 16. The raw material warehouse 16 is connected to the multi-stage suspension preheating unit 17, and the material is transported to the multi-stage suspension preheating unit 17 through the raw material warehouse 16; the finished product warehouse 12 is used to receive the finished product material after being cooled by the cooling cyclone 8.
[0029] In this embodiment, the materials separated from the four-stage cyclone 4 enter the decomposition furnace 6 in two ways. The materials are distributed in the decomposition furnace 6 in two layers, with the upper layer accounting for 50%-90% and the lower layer accounting for 10%-50%. Furthermore, a lower hot carbon reduction zone and an upper combustion decomposition zone are formed in the decomposition furnace 6; wherein, the distribution ratio of the upper combustion-supporting air in the decomposition furnace 6 is 50%-90%, and the distribution ratio of the lower combustion-supporting air is 10%-50%; the distribution ratio of the upper fuel in the decomposition furnace 6 is 50%-90%, and the distribution ratio of the lower fuel is 10%-50%. Through the proportional distribution of different materials, combustion-supporting air and fuel in the upper and lower layers, a lower hot carbon reduction zone and an upper combustion decomposition zone are formed in the decomposition furnace 6. If there is more combustion-supporting air and fuel in the upper layer of the decomposition furnace 6, the materials are fully burned to form an upper combustion decomposition zone. If there is more material in the lower layer of the decomposition furnace 6 and less combustion-supporting air and fuel, the materials are not fully burned, and a reduction reaction occurs, so that most of the NOx produced by the fuel reacts with CO in the reduction zone to become N2 and CO2, forming a lower hot carbon reduction zone.
[0030] Furthermore, the combustion decomposition zone is a region where heat is concentratedly released. Adding materials to this region can absorb heat and balance the temperature, so that the temperature is stably controlled at 900-1000°C. For example, when the temperature is high, the input of materials is increased, and when the temperature is low, the input of materials is reduced to avoid the generation of more thermal nitrogen oxides. By controlling the temperature within this region, the limestone can be completely decomposed into lime (CaO) without excessively burning the lime into dead lime (lime calcined at a temperature above 1100°C). The generated fuel-type nitrogen oxides are suppressed and reduced by adding pulverized coal in the lower hot carbon reduction zone. The pulverized coal that has not been completely burned is ensured to be burned out by adding combustion-supporting air in the upper combustion decomposition zone.
[0031] In this embodiment, both the precalciner 6 and the fluidized bed suspension cooling furnace 7 are equipped with a central constriction structure to create a gushing effect. When the material and fuel pass through the central constriction structure, the airflow velocity suddenly increases and the pressure changes, resulting in strong turbulence and mixing, which prevents laminar flow and promotes the full dispersion, mixing, and combustion of the material and fuel. Furthermore, the inlet of the fuel mill 15 on the precalciner 6 is located at the constriction structure. Due to the limited space in the precalciner 6, the fuel inlet is located at the constriction structure, which allows for more dispersion of the fuel upon entry into the precalciner 6. The airflow velocity increases at the central constriction structure, enabling rapid fuel dispersion and combustion. Furthermore, the fuel mill 15 enters the precalciner 6 in two ways, one above and one below, to prevent fuel accumulation in the precalciner 6. This dual entry reduces fuel accumulation, accelerates the mixing of fuel and material, and speeds up the fuel's combustion rate.
[0032] Furthermore, a plurality of middle necking structures are provided at different positions in the furnace, so that a gushing effect can be formed at multiple positions in the furnace.
[0033] 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 extracted from the first-stage cyclone 1 by the high-temperature air can be transported to the raw material mill 14 and the fuel mill 15 as a drying heat source to heat the material and fuel respectively.
[0034] 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 it does not affect the overall structure and process flow.
[0035] 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 to the decomposition furnace 6 by the cooling cyclone 8 can be controlled separately, so that the proportional distribution of combustion air in the decomposition furnace 6 can meet the proportional distribution of the lower combustion decomposition zone and the upper hot carbon reduction zone.
[0036] Furthermore, the cooling cyclone 8 can transfer the hot air after heat exchange, and the combustion air used by the decomposition furnace 6 does not come from the cold air in the atmosphere. The heat of the high-temperature lime that enters the cooling furnace after separation by the five-stage cyclone 5 is cooled by the fluidized bed suspension cooling furnace 7. Almost all of the heat is taken away by the air entering the cooling cyclone 8, which not only heats the air required for coal combustion in the calcining furnace and saves coal, but also quickly cools the high-temperature lime brought by the five-stage cyclone 5, making it easier to store and transport.
[0037] In this embodiment, the first-stage cyclone 1 is composed of two cyclones arranged side by side, and a flap valve is provided between each cyclone and the third-stage cyclone 3, namely the first flap valve 1-1 and the second flap valve 1-2; a third flap valve 2-1 is provided between the second-stage cyclone 2 and the four-season cyclone; a fourth flap valve 3-1 is provided between the third-stage cyclone 3 and the fifth-stage cyclone 5; the fourth-stage cyclone 4 and the decomposition furnace 6 are connected through a dividing valve 4-2, and the dividing valve 4-2 divides the material into two paths to enter the decomposition furnace 6, a fifth flap valve 4-1 is provided between the fourth-stage cyclone 4 and the dividing valve 4-2, and a sixth flap valve 4-3 and a seventh flap valve 4-4 are provided between the dividing valve 4-2 and the decomposition furnace 6 respectively; an eighth flap valve 5-1 is provided between the fifth-stage cyclone 5 and the fluidized bed suspension cooling furnace 7.
[0038] In this embodiment, the cooling cyclone 8 is connected to the finished product conveyor 11. After the finished 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.
[0039] Working principle: The direction of materials, fuel and air flow during the operation of this system.
[0040] Material flow: The material in the raw material warehouse 16 enters the first-level cyclone 1 through the connecting pipe. During the transportation of the material through the connecting pipe, the material undergoes heat exchange with air, and the material is carried by the airflow into the first-level cyclone 1 for gas-solid separation; the separated material enters the connecting pipe from the third-level cyclone 3 to the second-level cyclone 2 for heat exchange with air, and the material is carried by the airflow into the second-level cyclone 2 for gas-solid separation; the separated material enters the connecting pipe from the fourth-level cyclone 4 to the third-level cyclone 3 for heat exchange with air, and the material is carried by the airflow into the third-level cyclone 3 for gas-solid separation; the separated material enters the fifth-level cyclone 5 to the After the material-gas heat exchange is carried out in the connecting pipe of the fourth-stage cyclone 4, the material is brought into the fourth-stage cyclone 4 for gas-solid separation; the separated material enters the decomposition furnace 6, where the material is calcined and decomposed. The decomposed material is divided into two paths, one path enters the fifth-stage cyclone 5 with the rising air flow, and then enters the fluidized bed suspension cooling furnace 7 after separation, and the other path settles to the bottom of the decomposition furnace 6 and then enters the fluidized bed suspension cooling furnace 7; the material is fully mixed with the cold air in the fluidized bed suspension cooling furnace 7 for heat exchange, and then floats up to two parallel cooling cyclones 8 to be separated and collected as finished materials.
[0041] Fuel flow: The fuel from the fuel mill 15 is fed into the decomposition furnace 6 through a pneumatic conveying pipe, and the burners are distributed in multiple layers and multiple points.
[0042] Air flow direction: Under the suction force 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 in a negative pressure state. Most of the required cooling air enters horizontally from the lower part of the fluidized bed suspension cooling furnace 7, and the bottom is supplied with air by the fluidizing fan 10, so that the material is suspended and fluidized in the furnace for gas-solid heat exchange. The heated air flow enters the two parallel cooling cyclones 8 from the top of the fluidized bed suspension cooling furnace 7 for gas-solid separation. The hot gas enters the lower part of the decomposition furnace 6 in two ways as combustion-supporting air. 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 in sequence, and the flue gas coming out of the first-stage cyclone 1 enters the raw material mill 14 and the fuel mill 15 respectively as a drying heat source.
[0043] Those skilled in the art will readily appreciate other embodiments of the present invention after considering the specification and practicing the embodiments of the present invention. This application is intended to cover any variations, uses, or adaptations of the present invention that follow the general principles of the present invention and include common knowledge or customary techniques in the art that are not covered by this application. The specification and embodiments are intended to be exemplary only, and the true scope and spirit of the present invention are indicated by the appended claims.
Claims
1. A low-nitrogen energy-saving calcination system for high-activity lime based on thermal carbon reduction technology, characterized in that: include: Multi-stage suspension preheating unit, suspension low-nitrogen combustion unit, fluidized bed suspension cooling unit; The multi-stage suspension preheating unit is used to suspend and preheat the material, and the multi-stage suspension preheating unit includes multiple groups of connected cyclones; The suspended low-nitrogen combustion unit includes a decomposition furnace, which is connected to the cyclone in the multi-stage suspended preheating unit and is used to receive the preheated material transported from the cyclone; The cyclone at the end of the plurality of cyclone groups is used to receive the material after combustion and decomposition in the decomposition furnace and perform gas-solid separation on the material; The fluidized bed suspension cooling unit includes a fluidized bed suspension cooling furnace and two cooling cyclones arranged in parallel. The fluidized bed suspension cooling furnace is used to receive the material separated by the terminal cyclone and cool the material. The two cooling cyclones arranged in parallel are used to cool and separate the gas and solid of the material after being cooled by the fluidized bed suspension cooling furnace.
2. The low-nitrogen energy-saving calcination system for high-activity lime based on thermal carbon reduction technology according to claim 1 is characterized in that: The multi-stage suspension preheating unit includes a first-stage cyclone, a second-stage cyclone, a third-stage cyclone, a fourth-stage cyclone and a fifth-stage cyclone, wherein the fifth-stage cyclone is the terminal cyclone. A first connecting air duct is provided between the inlet of the first-stage cyclone and the inlet of the second-stage cyclone, and the first connecting air duct is used to receive materials transmitted from the raw material warehouse. A second connecting air duct is provided between the inlet of the second-stage cyclone and the inlet of the third-stage cyclone, a third connecting air duct is provided between the inlet of the third-stage cyclone and the inlet of the fourth-stage cyclone, and a fourth connecting air duct is connected between the inlet of the fourth-stage cyclone and the inlet of the fifth-stage cyclone. The outlet of the first-stage cyclone is connected to the second connecting air duct, the outlet of the second-stage cyclone is connected to the third connecting air duct, and the outlet of the third-stage cyclone is connected to the fourth connecting air duct through a material pipeline. The outlet of the fifth-stage cyclone is connected to the fluidized bed suspension cooling furnace, the outlet of the fourth-stage cyclone is connected to the material inlet of the decomposition furnace, and the inlet of the fifth-stage cyclone is connected to the material outlet at the top of the decomposition furnace.
3. The low-nitrogen energy-saving calcination system for high-activity lime based on thermal carbon reduction technology according to claim 2 is characterized in that: The material outlet at the lower part of the decomposition furnace is communicated with the fluidized bed suspension cooling furnace.
4. The low-nitrogen energy-saving calcination system for high-activity lime based on thermal carbon reduction technology according to claim 3 is characterized in that: It also includes a fluidizing fan, which is connected to the gas inlet of the fluidized bed suspension cooling furnace. 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.
5. The low-nitrogen energy-saving calcination system for high-activity lime based on thermal carbon reduction technology according to claim 4 is characterized in that: The materials separated from the four-stage cyclone enter the decomposition furnace in two ways; The materials in the decomposition furnace are distributed in two layers, the upper layer accounts for 50%-90% and the lower layer accounts for 10%-50%.
6. The low-nitrogen energy-saving calcination system for high-activity lime based on thermal carbon reduction technology according to claim 5 is characterized in that: The decomposition furnace is divided into a lower combustion decomposition zone and an upper hot carbon reduction zone; The combustion-supporting gas includes an upper layer of combustion-supporting air and a lower layer of combustion-supporting air. The distribution ratio of the upper layer of combustion-supporting air in the decomposition furnace is 50%-90%, and the distribution ratio of the lower layer of combustion-supporting air is 10%-50%. The distribution ratio of the upper layer fuel in the decomposition furnace is 50%-90%, and the distribution ratio of the lower layer fuel is 10%-50%.
7. The low-nitrogen energy-saving calcination system for high-activity lime based on thermal carbon reduction technology according to claim 6 is characterized in that: The gas path connecting the gas outlet of the cooling cyclone and the gas inlet of the decomposition furnace is divided into two paths, the upper and lower gas paths respectively corresponding to the lower hot carbon reduction zone and the upper combustion decomposition zone in the decomposition furnace.
8. The low-nitrogen energy-saving calcination system for high-activity lime based on thermal carbon reduction technology according to claim 7 is characterized in that: Both the upper and lower gas paths are provided with gate valves for controlling the ratio of combustion-supporting air flowing into the lower hot carbon reduction zone and the upper combustion decomposition zone.
9. The low-nitrogen energy-saving calcination system for high-activity lime based on thermal carbon reduction technology according to claim 4, characterized in that: The decomposition furnace and the fluidized bed suspension cooling furnace are both provided with a constriction structure in the middle to form a gushing effect; The inlet position of the fuel mill provided on the decomposition furnace is provided at the necking structure.
10. The low-nitrogen energy-saving calcination system for high-activity 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 cyclone located at the head end of the multiple groups of cyclones. The gas in the cyclone that has undergone heat exchange is passed into the raw material mill and the fuel mill through the high-temperature fan for preheating.