Combustion decomposition furnace and lime calcining system

Abstract

The application provides a combustion decomposition furnace and a lime calcining system, and belongs to the technical field of limestone calcining. Specifically, the combustion decomposition furnace comprises a decomposition furnace body and a first necking structure. A gas inlet and a fuel inlet are arranged on the decomposition furnace body. The fuel inlet is arranged at the first necking structure, and the position of the gas inlet is lower than that of the first necking structure. In the combustion decomposition furnace provided in the example embodiment, the position of the gas inlet is lower than that of the first necking structure. When the gas enters the decomposition furnace body through the gas inlet and passes through the first necking structure, the spray effect occurs due to the change of flow rate, and the fuel entering from the first necking structure is driven to move upward together. Under the action of the airflow, the fuel cannot move downward, and the accumulation of the fuel at the bottom of the decomposition furnace body is avoided, so that the phenomenon of insufficient combustion of the fuel is avoided. Meanwhile, the fuel inlet is arranged at the position of the first necking structure, and can be more quickly and fully mixed and combusted with the gas under the spray effect.

Description

Technical Field

[0001] This application relates to the field of limestone calcination technology, and more specifically, to a combustion decomposition furnace and a limestone calcination system. Background Technology

[0002] Currently, domestic lime calcination systems mainly use vertical kilns and rotary kilns. The raw material is lumpy limestone, which 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. During the calcination process, pulverized coal or other fuels are added to rapidly heat the lime. However, existing vertical and rotary kilns have inlets at the bottom for introducing pulverized coal or other fuels. This results in incomplete combustion of some of the pulverized coal, affecting the calcination efficiency and potentially producing toxic gases such as carbon monoxide. Utility Model Content

[0003] The purpose of this application is to provide a combustion decomposition furnace and a lime calcination system, which aims to solve the problem that in the related technology, the pulverized coal inlet of the vertical kiln and rotary kiln is set at the bottom, which is not conducive to the complete combustion of pulverized coal, affects the lime calcination efficiency, and may produce toxic gases such as carbon monoxide.

[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 combustion decomposition furnace is provided, comprising:

[0006] A decomposition furnace body, wherein the decomposition furnace body has a first constriction structure;

[0007] The decomposition furnace body is provided with a gas inlet and a fuel inlet. The fuel inlet is located at the first constriction structure, and the gas inlet is located below the position of the first constriction structure.

[0008] In one exemplary embodiment of this application, the decomposition furnace body includes a combustion section and a deposition section located at the bottom end, the first constriction structure is located between the combustion section and the deposition section, and the gas inlet is located above the deposition section.

[0009] In one exemplary embodiment of this application, the top end of the combustion section is provided with a first material outlet, and the bottom end of the deposition section is provided with a second material outlet. Both the first material outlet and the second material outlet are connected to the cooling furnace.

[0010] In one exemplary embodiment of this application, the first constriction structure is hourglass-shaped, including a central constriction and open openings at both ends of the central constriction, and the fuel inlet is disposed at the central constriction.

[0011] In one exemplary embodiment of this application, the ratio of the diameter of the central constriction to the maximum diameter of the open portion ranges from 0.5 to 0.9.

[0012] In one exemplary embodiment of this application, the ratio of the height of the central constriction to the overall height of the first constriction structure is in the range of 0-0.5.

[0013] In one exemplary embodiment of this application, both the gas inlet and the fuel inlet are provided in two separate, vertically arranged sections. By controlling the ratio of the combustion-supporting gas to the fuel, two combustion zones with different states are formed within the combustion decomposition furnace.

[0014] In one exemplary embodiment of this application, the decomposition furnace body also has a second constriction structure, and the two fuel inlets are respectively configured to correspond to the first constriction structure and the second constriction structure.

[0015] According to a second aspect of this application, a lime calcination system is provided, comprising the aforementioned combustion decomposition furnace, and further comprising:

[0016] The cooling unit includes a suspension cooling furnace, which is connected to the material outlet of the decomposition furnace and is used to cool the material.

[0017] In one exemplary embodiment of this application, the cooling unit further includes a separating cyclone, the outlet of which is connected to the combustion decomposition furnace, and the air path of the separating cyclone is divided into two paths to enter the combustion decomposition furnace.

[0018] The exemplary embodiments of this application may have some or all of the following beneficial effects:

[0019] The combustion decomposition furnace provided in the example embodiment of this application has a first constriction structure, a gas inlet, and a fuel inlet. The fuel inlet is located at the first constriction structure, and the gas inlet is located below the first constriction structure. When the gas enters the decomposition furnace body through the gas inlet and passes through the first constriction structure, a jetting effect occurs due to the change in flow velocity, which drives the fuel entering from the first constriction structure to move upward together. Under the action of the airflow, the fuel will not move downward, avoiding the accumulation of fuel at the bottom of the decomposition furnace body, which would lead to incomplete combustion of the fuel. At the same time, the fuel inlet is located at the first constriction structure, which allows for faster and more complete mixing and combustion with the gas under the jetting effect.

[0020] 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

[0021] 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.

[0022] Figure 1 A schematic diagram of a combustion decomposition furnace according to Embodiment 1 of this application is shown;

[0023] Figure 2 A schematic diagram of the first constriction structure in Embodiment 1 of this application is shown;

[0024] Figure 3 A schematic diagram of the lime calcination system in Embodiment 2 of this application is shown.

[0025] Explanation of reference numerals in the attached figures:

[0026] 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. Material distribution valve; 4-3. Sixth flap valve; 4-4. Seventh flap valve; 5. Fifth cyclone separator; 5-1. Eighth flap valve; 6. Decomposition furnace body; 61. Material collection zone; 62. Combustion decomposition zone; 63. Hot carbon reduction zone; 64. Second combustion gas inlet; 65. First combustion gas inlet; 66. First fuel inlet; 67. First material inlet; 68. Second combustion gas inlet. 69. Second material inlet; 601. First narrowing structure; 6011. Opening; 6012. Middle narrowing; 602. Second narrowing structure; 603. Preheating and decomposition zone; 6-1. Gate valve; 7. Fluidized bed suspension cooling furnace; 8. Separation cyclone; 8-1. Ninth flap valve; 10. Fluidized blower; 11. Finished product conveyor; 12. Finished product warehouse; 13. High temperature blower; 14. Raw material mill; 15. Fuel mill; 16. Raw material warehouse; 17. Multi-stage suspension preheating unit; 18. Fluidized bed suspension cooling unit; 19. Suspension low-NOx combustion unit; 20. First material outlet; 21. Second material outlet. Detailed Implementation

[0027] 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.

[0028] 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.

[0029] 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.

[0030] Example 1

[0031] This embodiment provides a specific implementation of a combustion decomposition furnace, such as... Figure 1 As shown, the decomposition furnace body 6 has a first constriction structure 601, a gas inlet, and a fuel inlet. The fuel inlet is located at the first constriction structure 601, and the gas inlet is located below the first constriction structure 601. When the gas enters the decomposition furnace body 6 through the gas inlet and passes through the first constriction structure 601, a jetting effect occurs due to the change in flow velocity, which drives the fuel entering from the first constriction structure 601 to move upward together. Under the action of the airflow, the fuel will not move downward, avoiding the accumulation of fuel at the bottom of the decomposition furnace body 6, which would lead to incomplete combustion of the fuel. At the same time, the fuel inlet is located at the first constriction structure 601, which allows it to mix and burn more quickly and fully with the gas under the jetting effect.

[0032] Furthermore, during the lime calcination process, there are numerous inlets, such as gas inlets, material inlets, and fuel inlets. The gas inlet is for introducing combustion-supporting gas, which is usually air. After entering the decomposition furnace body 6, the air flows upward. Placing the gas inlet at the bottom of the numerous inlets allows the air to carry materials and fuel along with it as it flows upward within the decomposition furnace body 6. If the material and fuel inlets were located below the gas inlet, it would be difficult for the air to carry the materials and fuel along for sufficient flow when it flows upward. Mixing can easily cause materials and fuel to accumulate at the bottom of the decomposition furnace body 6. In addition, when air flows through the first constriction structure 601, it is accelerated when passing through the lower opening 6011, reaches its fastest speed when passing through the middle constriction 6012, and diffuses and slows down when passing through the upper opening 6011. Therefore, setting the fuel inlet at the middle constriction 6012 position allows the fuel to be carried upward by the faster airflow as soon as it enters the decomposition furnace body 6 and be fully mixed at the upper opening 6011.

[0033] In this embodiment, the decomposition furnace body 6 includes a combustion section and a deposition section. The deposition section is located at the bottom end of the decomposition furnace body 6. The first constriction structure 601 is located between the combustion section and the deposition section. The gas inlet is located at the transition position between the deposition section and the first constriction structure 601. The gas inlet is located below the first constriction structure 601, so that when the gas enters the decomposition furnace body 6 and flows upward, it first passes through the first constriction structure 601. Under the influence of the first constriction structure 601, the gas flow rate changes, and a jetting effect is generated at the first constriction position, which can accelerate the flow of gas and generate turbulence, so that the gas, materials and fuel can be quickly and evenly mixed.

[0034] In this embodiment, a first material outlet 20 is provided at the top of the combustion section, and a second material outlet 21 is provided at the bottom of the deposition section. Both the first material outlet 20 and the second material outlet 21 are connected to the cooling furnace. Most of the combusted material enters the cooling furnace through the first material outlet 20 with the airflow, while a small portion of the combusted material is deposited in the deposition section and enters the cooling furnace through the second material outlet 21. The second material outlet 21 can prevent excessive accumulation of material at the bottom of the decomposition furnace body 6, which would affect the calcination effect of the decomposition furnace body 6.

[0035] In this embodiment, as Figure 2As shown, the first constriction structure 601 is hourglass-shaped, including a central constriction 6012 and open openings 6011 at both ends of the central constriction 6012. The fuel inlet is located at the central constriction 6012. When the airflow entering the decomposition furnace 6 passes through the first constriction structure 601, the diameter decreases at the lower open opening 6011, and the airflow accelerates. The flow velocity is fastest when it reaches the central constriction 6012. When the airflow flows upward from the central constriction 6012 into the upper open opening 6011, the diameter inside the decomposition furnace 6 increases, the airflow speed slows down, and it diffuses outward to form turbulence, thereby improving the mixing efficiency of gas and fuel. Specifically, by setting the fuel inlet at the central constriction 6012, the gas flow velocity is fastest at the central constriction 6012. Fuel entering from here can flow upward with the airflow at a relatively fast speed and diffuse outward to the periphery of the decomposition furnace 6 at the upper open opening 6011, fully mixing with the gas and improving the mixing efficiency of fuel and gas.

[0036] In this embodiment, as Figure 2 As shown, the ratio of the diameter of the central constriction 6012 to the maximum diameter of the open opening 6011 ranges from 0.5 to 0.9, i.e., d / D is 0.5-0.9. The ratio of the height of the central constriction 6012 to the overall height of the first constriction structure 601 ranges from 0 to 0.5, i.e., h / H is 0-0.5. This design allows for a more reasonable flow velocity and mixing efficiency when the airflow passes through. Specifically, the height of the central constriction 6012 can be zero, i.e., there is no central constriction 6012, only two open openings 6011. When the air flows through, it will experience a process of first accelerating and then decelerating, which will also create a jetting effect. In this case, the fuel inlet is located at the connection position of the two open openings 6011.

[0037] In other embodiments, the first constriction structure 601 only needs to satisfy that the upper and lower ends have different inner diameter changes, so that the airflow can undergo acceleration and deceleration processes when it flows through it.

[0038] In this embodiment, there are two gas inlets and two fuel inlets, one above the other. By controlling the ratio of combustion-supporting gas to fuel, two combustion zones with different states are formed within the decomposition furnace body 6.

[0039] Furthermore, the decomposition furnace body 6 also has a second constriction structure 602, and the two fuel inlets are respectively set to correspond to the first constriction structure 601 and the second constriction structure 602.

[0040] Furthermore, the two gas inlets are the first combustion-supporting gas inlet 65 and the second combustion-supporting gas inlet 64, the two fuel inlets are the first fuel inlet 66 and the second fuel inlet 68, and there are also two material inlets, namely the first material inlet 67 and the second material inlet 69; and the furnace cavity of the decomposition furnace body 6 is formed from bottom to top into a material collection zone, a preheating decomposition zone, a hot carbon reduction zone and a combustion decomposition zone, wherein the material collection zone 61 is a deposition section, and the preheating decomposition zone 603, the hot carbon reduction zone 62 and the combustion decomposition zone 63 are combustion sections. The first material inlet 67, the first combustion gas inlet 65, and the first fuel inlet 66 are correspondingly set to the preheating decomposition zone 603. The second material inlet 69 and the second fuel inlet 68 are correspondingly set to the hot carbon reduction zone 62. The second combustion gas inlet 64 is correspondingly set to the combustion decomposition zone 63. The material, combustion gas, and fuel are all divided into two paths to enter the decomposition furnace body 6. The ratio of the material, combustion gas, and fuel entering the decomposition furnace body 6 is controlled so that the hot carbon reduction zone 62 and the combustion decomposition zone 63 are formed in the furnace cavity of the decomposition furnace body 6.

[0041] Furthermore, in the combustion decomposition zone 63, the proportion of combustion-supporting gas is relatively high, while the proportion of fuel and material is relatively low, allowing the material to burn completely. In the preheating decomposition zone 603, the proportion of combustion-supporting gas is relatively low, while the proportion of material and fuel is relatively high. Incomplete combustion of fuel produces carbon monoxide, which increases the combustion temperature of the material. As the material and fuel rise to the hot carbon reduction zone, the combustion-supporting gas is completely consumed. The nitrogen oxides produced in the preheating decomposition zone 603 are reduced here, converting them into carbon dioxide and nitrogen, reducing the need for exhaust gas treatment in subsequent processes and lowering environmental pollution. When the material rises to the combustion decomposition zone 63, the high proportion of combustion-supporting gas ensures complete combustion of the material.

[0042] In this embodiment, the second gas inlet is located above the thermal carbon reduction zone 62. When the combustion-supporting gas is introduced into the second gas inlet, a combustion decomposition zone 63 is formed above the thermal carbon reduction zone 62. Most of the combustion-supporting gas entering from the second gas inlet is in the combustion decomposition zone 63 above the thermal carbon reduction zone 62. When the materials and fuels flow upward under the carrying of the airflow, they will be fully burned and exhausted after passing through the combustion decomposition zone, thus avoiding the outflow of unburned materials and fuels.

[0043] In this embodiment, the first combustion-supporting gas inlet 65 is located between the collection zone 61 and the preheating and decomposition zone 603. The position of the first fuel inlet 66 is higher than the position of the first combustion-supporting gas inlet 65, and the position of the first material inlet 67 is higher than the position of the first combustion-supporting gas inlet 65. This design allows the combustion-supporting gas to enter from the first combustion-supporting gas inlet 65 and flow upward, thereby mixing and burning the fuel and material above. It also prevents the material and fuel from entering from below the first combustion-supporting gas inlet 65, which would make it difficult to fully mix them using the flow of the combustion-supporting gas.

[0044] Furthermore, a first constriction structure 601 is provided between the material collection zone 61 and the preheating decomposition zone 603 of the decomposition furnace body 6. The position of the first combustion-supporting gas inlet 65 is lower than the position of the first constriction structure 601, the position of the first fuel inlet 66 corresponds to the position of the first constriction structure 601, and the position of the first material inlet 67 is higher than the position of the first constriction structure 601. When the combustion-supporting gas enters from the first combustion-supporting gas inlet 65, it flows upward through the first constriction structure 601, which changes the flow velocity and forms turbulence, accelerating the mixing of fuel and material. The first fuel inlet 66 is set at the position of the first constriction structure 601. Since the flow velocity of the combustion-supporting gas is faster at the first constriction structure 601, the fuel can be quickly mixed with the material above.

[0045] In this embodiment, the decomposition furnace body 6 is provided with a second constriction structure 602, which is located above the second material inlet 69. The second fuel inlet 68 is positioned corresponding to the second constriction structure 602. The positions of the second material inlet 69 and the second combustion gas inlet 64 are both higher than the position of the second constriction structure 602, and the position of the second combustion gas inlet 64 is higher than the position of the second material inlet 69. A hot carbon reduction zone 62 is formed between the first constriction structure 601 and the second constriction structure 602, and a combustion decomposition zone 63 is formed above the second constriction structure 602.

[0046] In this embodiment, the proportion of material in the upper layer of the furnace cavity of the decomposition furnace body 6 is 50%-90%, and the proportion in the lower layer is 10%-50%; the proportion of combustion-supporting gas in the upper layer is 50%-90%, and the proportion in the lower layer is 10%-50%; the proportion of fuel in the upper layer is 50%-90%, and the proportion in the lower layer is 10%-50%. By controlling the proportion range of material, combustion-supporting gas, and fuel in the lower hot carbon reduction zone 62 and the upper combustion decomposition zone 63, the material is fully combusted and nitrogen oxides are eliminated as much as possible.

[0047] In this embodiment, the combustion temperature of the combustion decomposition zone 63 is controlled between 900℃ and 1000℃ to avoid generating too much thermal nitrogen oxides.

[0048] Example 2

[0049] This embodiment provides a specific implementation of a lime calcination system, including the combustion decomposition furnace in Embodiment 1, and a cooling unit. The cooling unit includes a suspension cooling furnace, and both the first material outlet and the second material outlet are connected to the suspension cooling furnace. The suspension cooling furnace is used to cool the material. Further, the cooling unit also includes a separation cyclone, the air outlet of which is connected to the combustion decomposition furnace, and the air path of the separation cyclone is divided into two paths to enter the combustion decomposition furnace.

[0050] like Figure 3As 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 multi-stage suspension preheating unit 17 includes multiple sets of cyclones connected by connecting pipes. The suspension low-NOx combustion unit 19 includes a decomposition furnace body 6, which is connected to the cyclones in the multi-stage suspension preheating unit 17. The decomposition furnace body 6 is used to receive materials conveyed from the cyclones. The fluidized bed suspension cooling unit 18 includes a fluidized bed suspension cooling furnace 7 and two parallel-connected separation cyclones 8. The fluidized bed suspension cooling furnace 7 is used to receive and cool the materials after combustion in the decomposition furnace body 6 and gas-solid separation in the cyclones. The two parallel-connected separation cyclones 8 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.

[0051] 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 separation cyclones 8 to complete the separation, which greatly reduces the system's operating resistance, power consumption, and thus cost. The two parallel separation 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 separation cyclone 8 for further heat exchange and simultaneous gas-solid separation. The material separated in the separation 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 separation cyclone 8 for gas-solid separation.

[0052] 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 body 6. Only after the fuel is transported can the material in the decomposition furnace body 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 to the multi-stage suspension preheating unit 17 through the raw material silo 16. The finished product silo 12 is used to receive the finished material after being cooled by the separation cyclone 8.

[0053] In this embodiment, 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. A high-temperature fan 13 is connected to the primary cyclone 1. 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; a second connecting duct is provided between the inlet of the secondary cyclone 2 and the inlet of the tertiary cyclone 3; and a connecting duct is provided between the inlet of the tertiary cyclone 3 and the inlet of the quaternary cyclone 4. A fourth connecting duct is provided between the inlet of the third connecting duct, 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 is connected to the second connecting duct, the outlet of the second-stage cyclone 2 is connected to the third connecting duct, and the outlet of the third-stage cyclone 3 is connected to the fourth connecting duct through 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 body 6. The inlet of the fifth-stage cyclone 5 is connected to the material outlet at the top of the decomposition furnace body 6.

[0054] 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 the material 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 gas-air heat exchange, and is then carried by the airflow into the secondary cyclone separator 2 for gas-solid separation. After separation, the material enters the third connecting duct between the quaternary cyclone separator 4 and the tertiary cyclone separator 3 for gas-air heat exchange, and is then carried by the airflow into the secondary cyclone separator 2 for gas-solid separation. The material is introduced into the three-stage cyclone separator 3 for gas-solid separation. After separation, the 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 introduced into the four-stage cyclone separator 4 for gas-solid separation. The separated material then enters the decomposition furnace body 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 settles to the bottom of the decomposition furnace body 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 body 6, which pre-heats the material and reduces the calcination time in the decomposition furnace body 6.

[0055] 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 point between the fifth-stage cyclone 5, the decomposition furnace body 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 process of gas-solid heat exchange, the heated gas flow enters the parallel-connected separation cyclone 8 from the top of the furnace for gas-solid separation. The hot gas, acting as combustion air, enters the decomposition furnace body 6 through two separate paths. The flue gas generated in the material decomposition furnace body 6 enters the multi-stage suspension preheating unit 17 sequentially from the top of the decomposition furnace body 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 separation cyclone 8 is the finished product, which is stored or transported to the finished product warehouse 12. Simultaneously, placing the inlet of the fluidizing blower 10 at the bottom of the fluidized bed suspension cooling furnace 7 can also prevent material collapse. The fluidizing blower 10 blows air upwards from the bottom of the fluidized bed suspension cooling furnace 7, preventing material accumulation at the bottom of the furnace.

[0056] 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.

[0057] In this embodiment, the material separated from the four-stage cyclone 4 enters the decomposition furnace 6 in two separate paths. 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 combustion decomposition zone 63 and an upper hot carbon reduction zone 62 are formed in the decomposition furnace body 6. The distribution ratio of combustion air in the upper layer of the decomposition furnace body 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 body 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, an upper combustion decomposition zone 63 and a lower hot carbon reduction zone 62 are formed in the decomposition furnace body 6. If there is more material in the lower layer of the decomposition furnace body 6 and less combustion air and fuel, the material will not burn completely, forming the lower hot carbon reduction zone 62, where a reduction reaction will occur. Most of the NOx produced by the fuel will react with CO in the reduction zone to become N2 and CO2. When there is more material in the upper layer of the decomposition furnace body 6 and more combustion air and fuel, the material will burn completely, forming the combustion decomposition zone 63.

[0058] Furthermore, the combustion decomposition zone 63 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℃, thus avoiding the generation of excessive 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℃). Unburned coal powder is ensured to burn completely by supplementing combustion air in the upper combustion decomposition zone 63.

[0059] In this embodiment, both the decomposition furnace body 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 body 6 is located at the constriction structure. Due to the limited space in the decomposition furnace body 6, placing the fuel inlet at the constriction structure allows for greater dispersion of fuel upon entering the decomposition furnace body 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 body 6 through two paths, upper and lower, preventing fuel accumulation in the decomposition furnace body 6. This dual entry reduces fuel accumulation, accelerates the mixing of fuel and materials, and speeds up the combustion rate.

[0060] 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.

[0061] 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.

[0062] 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.

[0063] In this embodiment, the separating cyclone 8 is connected to the upper hot carbon reduction zone 62 and the lower combustion decomposition zone 63 of the decomposition furnace body 6 via connecting pipes. Each connecting pipe is equipped with a gate valve 6-1. By controlling the gate valve 6-1, the amount of combustion air delivered from the separating cyclone 8 to the decomposition furnace body 6 can be controlled so that the proportion of combustion air in the decomposition furnace body 6 can meet the proportion of the upper combustion decomposition zone 63 and the lower hot carbon reduction zone 62.

[0064] Furthermore, the separating cyclone 8 can separate the hot air after heat exchange. The combustion air used in the decomposition furnace 6 does not come from 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 separating cyclone 8. This not only heats the air needed for coal combustion in the calcining furnace, thus saving coal, but also allows the high-temperature lime brought by the five-stage cyclone 5 to be cooled quickly, making it easier to store, transport and use.

[0065] 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 is equipped with a fourth flap valve 3-1 between itself and the quinary cyclone 5; the quinary cyclone 4 and the decomposition furnace body 6 are connected by a material distribution valve 4-2, which divides the material into two paths to enter the decomposition furnace body 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 body 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.

[0066] In this embodiment, the separating cyclone 8 is connected to the finished product conveyor 11. After the finished product material comes out of the separating 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 separating cyclones 8 and the finished product conveyor 11.

[0067] 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 combustion decomposition furnace, characterized in that, include: A decomposition furnace body, wherein the decomposition furnace body has a first constriction structure; The decomposition furnace body is provided with a gas inlet and a fuel inlet. The fuel inlet is located at the first constriction structure, and the gas inlet is located below the position of the first constriction structure.

2. The combustion decomposition furnace according to claim 1, characterized in that, The decomposition furnace body includes a combustion section and a deposition section located at the bottom. The first constriction structure is located between the combustion section and the deposition section, and the gas inlet is located above the deposition section.

3. The combustion decomposition furnace according to claim 2, characterized in that, The combustion section has a first material outlet at its top and the deposition section has a second material outlet at its bottom. Both the first and second material outlets are connected to the cooling furnace.

4. The combustion decomposition furnace according to claim 1, characterized in that, The first constriction structure is hourglass-shaped, including a central constriction and open sections at both ends of the central constriction, with the fuel inlet located at the central constriction.

5. The combustion decomposition furnace according to claim 4, characterized in that, The ratio of the diameter of the narrowed central opening to the maximum diameter of the open opening ranges from 0.5 to 0.

9.

6. The combustion decomposition furnace according to claim 4, characterized in that, The ratio of the height of the central constriction to the overall height of the first constriction structure is in the range of 0-0.

5.

7. The combustion decomposition furnace according to claim 1, characterized in that, Both the gas inlet and the fuel inlet have two inlets, one above the other. By controlling the ratio of combustion-supporting gas to fuel, two combustion zones with different states can be formed inside the combustion decomposition furnace.

8. The combustion decomposition furnace according to claim 7, characterized in that, The decomposition furnace body also has a second constriction structure, and the two fuel inlets are respectively set to correspond to the first constriction structure and the second constriction structure.

9. A lime calcination system, characterized in that, The combustion decomposition furnace according to any one of claims 1-7 further includes: The cooling unit includes a suspension cooling furnace, which is connected to the material outlet of the decomposition furnace and is used to cool the material.

10. The lime calcination system according to claim 9, characterized in that, The cooling unit also includes a separation cyclone, the outlet of which is connected to the combustion decomposition furnace, and the air path of the separation cyclone is divided into two paths to enter the combustion decomposition furnace.

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