Fluidized bed pyrolysis-combustion staged coupling device for low rank coal

Abstract

The utility model belongs to equipment technology and coal utilization method technical field discloses a kind of low-rank coal fluidized bed pyrolysis-burning grading coupling device.The device includes feeding module, fluidized bed pyrolysis furnace module and fluidized bed combustion furnace module, and the pyrolysis bed of fluidized bed pyrolysis furnace module is connected with feeding module, pyrolysis cyclone separation unit is communicated with pyrolysis bed, and fine coal powder in oil gas can be separated, so that fine coal powder can occur pyrolysis reaction;Circulating communication is equipped with feeding channel and return channel between the combustion bed of fluidized bed combustion furnace module and pyrolysis bed, so that hot semi-coke can be transported to combustion bed, and hot ash and slag generated by combustion reaction can be provided to pyrolysis bed, so that hot ash and slag can continue to carry out pyrolysis reaction with raw material coal.By the above setting, coal energy utilization gradation and grading quality utilization can be realized, conversion efficiency is improved, coal resources is saved, environmental protection benefit and economic benefit of the device are improved, and construction cost of the device can be effectively reduced.

Description

Technical Field

[0001] This utility model relates to the fields of equipment technology and coal utilization methods, and in particular to a fluidized bed pyrolysis-combustion staged coupling device for low-rank coal. Background Technology

[0002] Coal pyrolysis technology relies on high-volatile coal quality conditions and fully utilizes the hydrocarbon organic matter contained in the coal itself to decompose raw coal into three intermediate products: coal gas, tar, and semi-coke. Currently, many regions possess abundant high-volatile low-rank coals (such as lignite and bituminous coal). Direct combustion of these low-rank coals produces NO₂. X The problem is quite prominent, but it is very suitable for pyrolysis. Converting it into fuel gas for re-combustion through pyrolysis, or into feedstock gas for chemical production, is a better approach to treating these wastes.

[0003] Currently, most traditional low-rank coal pyrolysis methods use lump coal pyrolysis, which utilizes particles with a diameter of 10-180mm. Low-rank fine coal with a diameter of less than 10mm cannot be pyrolyzed and can only be used as a by-product for direct combustion of power coal or direct gasification for single conversion. This seriously wastes the portion of coal resources that can be graded and utilized, and fails to achieve the goal of energy cascade clean utilization or graded and quality-differentiated efficient clean conversion.

[0004] Therefore, there is an urgent need to design a fluidized bed pyrolysis-combustion staged coupling device for low-rank coal to solve the problems existing in the current technology. Utility Model Content

[0005] The purpose of this invention is to provide a fluidized bed pyrolysis-combustion staged coupling device for low-rank coal, which can realize the clean utilization of fuel in stages and the utilization of fuel in stages and by quality, and significantly improve the utilization rate of fuel resources.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] A low-rank coal fluidized bed pyrolysis-combustion staged coupling device includes: a feeding module, a fluidized bed pyrolysis furnace module, and a fluidized bed combustion furnace module, wherein:

[0008] The feeding module is used to provide raw coal to the fluidized bed pyrolysis furnace module;

[0009] The fluidized bed pyrolysis furnace module includes a pyrolysis bed and a pyrolysis cyclone separator unit. The pyrolysis bed is connected to the feeding module. The raw coal can undergo pyrolysis reaction in the pyrolysis bed and be graded to generate hot semi-coke and oil gas. The pyrolysis cyclone separator unit is connected to the pyrolysis bed and is used to separate fine coal powder from the oil gas so that the fine coal powder can undergo pyrolysis reaction after continuous heating in the pyrolysis bed.

[0010] The fluidized bed combustion furnace module includes a combustion bed, and a feeding channel and a return channel are circulated and connected between the combustion bed and the pyrolysis bed. The feeding channel is used to supply the hot semi-coke to the combustion bed, where the hot semi-coke can undergo a combustion reaction to generate hot ash. The return channel can supply the hot ash to the pyrolysis bed, so that the hot ash can form a new solid heat carrier and continue to undergo a pyrolysis reaction with the raw coal.

[0011] Preferably, the pyrolysis bed has a pyrolysis boiling section and a pyrolysis suspension section arranged sequentially from bottom to top and connected together. The pyrolysis boiling section is used to fill the raw coal and the hot ash residue, and the pyrolysis suspension section is used to absorb the oil and gas. The pyrolysis suspension section is provided with the pyrolysis cyclone separation unit. The particle size of the fine coal powder is smaller than the particle size of the raw coal that undergoes pyrolysis reaction in the pyrolysis boiling section.

[0012] Preferably, the fluidized bed pyrolysis furnace module further includes a first gas supply unit, which includes a primary hydrogen-rich hot coal gas supply pipeline and a secondary hydrogen-rich hot coal gas supply pipeline. One end of the primary hydrogen-rich hot coal gas supply pipeline is connected to one end of the secondary hydrogen-rich hot coal gas supply pipeline, and the other end of the primary hydrogen-rich hot coal gas supply pipeline is connected to the pyrolysis bed. It is used to supply the pyrolysis bed with primary hydrogen-rich hot coal gas and can lift the raw coal and the hot ash from bottom to top through the primary hydrogen-rich hot coal gas.

[0013] The other end of the secondary hydrogen-rich hot coal gas supply pipeline is connected to the pyrolysis bed and is at a higher connection height than the primary hydrogen-rich hot coal gas supply pipeline and the pyrolysis bed. The secondary hydrogen-rich hot coal gas supply pipeline is used to supply secondary hydrogen-rich hot coal gas to the pyrolysis bed and can disturb the pyrolysis reaction.

[0014] Preferably, the fluidized bed combustion furnace module further includes a second air supply unit, which includes a primary hot air supply pipeline and a secondary hot air supply pipeline. One end of the primary hot air supply pipeline is connected to one end of the secondary hot air supply pipeline, and the other end of the primary hot air supply pipeline is connected to the combustion bed. It is used to supply primary hot air to the combustion bed and can lift the hot semi-coke from bottom to top through the primary hot air, so that the hot semi-coke tumbles up and down and forms a fluidized state.

[0015] The other end of the secondary hot air supply pipeline is connected to the combustion bed and is at a higher connection height than the primary hot air supply pipeline to the combustion bed. The secondary hot air supply pipeline is used to supply secondary hot air to the combustion bed and can disturb the combustion reaction.

[0016] Preferably, the combustion bed includes a combustion boiling section and a combustion suspension section connected sequentially from bottom to top. The combustion boiling section is used to fill the hot semi-coke, and the combustion suspension section is used to absorb the flue gas generated by the combustion reaction.

[0017] The fluidized bed combustion furnace module also includes a combustion cyclone separation unit, which is disposed on one side of the combustion bed. The combustion suspension section is connected to the combustion cyclone separation unit through a flue gas channel, and the combustion boiling section is connected to the combustion cyclone separation unit through a return material channel. The combustion cyclone separation unit is used to separate fine coke powder and desulfurizing agent particles in the flue gas, so that the fine coke powder and the desulfurizing agent particles can return to the combustion boiling section through the return material channel and continue to participate in the combustion reaction.

[0018] Preferably, the system also includes a convection flue, which is vertically arranged on one side of the combustion cyclone separation unit. The upper air inlet of the convection flue is connected to the top of the combustion cyclone separation unit through a flow passage and is used to discharge the flue gas outward.

[0019] Preferably, the second air supply unit further includes an air preheating unit disposed in the convection flue. The air preheating unit inlet is connected to the air supply device, the air preheating unit outlet is connected to one end of the primary hot air supply pipeline and the secondary hot air supply pipeline, and the air preheating unit is thermally connected to the convection flue.

[0020] Preferably, the system also includes a steam-water circulation module, which comprises a steam drum, an economizer, a liquid supply pipe, a liquid delivery pipe, a steam-water delivery pipe, and a steam supply pipe. The steam drum is used for gas-liquid separation of steam and water, and has an exhaust port at its top. The economizer is located inside the convection flue, with its inlet connected to a water supply device and its outlet connected to the steam drum via the liquid supply pipe. The economizer is thermally connected to the convection flue so that the heat from the flue gas can be transferred to the cold water, and the heated cold water can be transferred to the steam drum. One end of the liquid delivery pipe is connected to the steam drum, and the other end is connected to the furnace wall cavity inlet of the fluidized bed combustion furnace module. The steam-water delivery pipe connects the furnace wall cavity outlet of the fluidized bed combustion furnace module to the steam drum. The steam supply pipe connects the user terminal to the exhaust port, allowing the steam after gas-liquid separation to be transmitted to the user terminal via the exhaust port and the steam supply pipe.

[0021] Preferably, the steam-water circulation module further includes a low-temperature superheater and a high-temperature superheater. Both the low-temperature superheater and the high-temperature superheater are installed on the steam supply pipe and along the steam flow direction. The low-temperature superheater and the high-temperature superheater are arranged sequentially. The low-temperature superheater is used to heat the steam in a primary manner, and the high-temperature superheater is used to heat the steam in a secondary manner to form superheated steam.

[0022] Preferably, both the high-temperature superheater and the low-temperature superheater are located inside the convection flue, and along the flow direction of the flue gas, the high-temperature superheater, the low-temperature superheater, the economizer, and the air preheating unit are arranged sequentially from top to bottom.

[0023] The beneficial effects of this invention are as follows: The low-rank coal fluidized bed pyrolysis-combustion staged coupling device provided in this embodiment optimizes the coal conversion method. By first carbonizing and upgrading the coal before combustion for energy supply, it achieves tiered energy utilization and graded utilization of coal resources, realizing the principle of efficient conversion of low-rank coal resources and improving coal resource conversion efficiency. Furthermore, this device can pyrolyze low-rank coal with a particle size of 0-10mm, thereby overcoming the limitation of traditional pyrolysis methods that can only process lump coal and pulverized coal, thus saving coal resources. In addition, by interconnecting the materials in the pyrolysis bed and the combustion bed, it enables high-temperature combustion of hot semi-coke, a clean fuel, in the combustion bed, reducing NO. X This process enhances the environmental and economic benefits of the equipment. Furthermore, the equipment shortens the fuel transport distance when the pyrolysis and combustion reactions are operated in separate furnaces. Since there is no intermediate conversion process, the hot semi-coke can directly enter the combustion bed for ignition and combustion, reducing preheating time and effectively reducing the investment and cost of constructing both the fluidized bed pyrolysis furnace module and the fluidized bed combustion furnace module simultaneously. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of the low-rank coal fluidized bed pyrolysis-combustion staged coupling device provided by this utility model.

[0025] In the picture:

[0026] 1. Feeding module;

[0027] 2. Fluidized bed pyrolysis furnace module; 211. Pyrolysis boiling section; 212. Pyrolysis suspension section; 22. Pyrolysis cyclone separation unit; 23. Feeding channel; 24. First gas supply unit; 241. Primary hydrogen-rich hot gas supply pipeline; 242. Secondary hydrogen-rich hot gas supply pipeline; 25. Oil and gas outlet;

[0028] 3. Fluidized bed combustion furnace module; 31. Combustion bed; 311. Combustion boiling section; 312. Combustion suspension section; 32. Return material channel; 33. Combustion cyclone separation unit; 34. Flue gas channel; 35. Return material channel; 36. Overflow port; 37. Secondary air supply unit; 371. Primary hot air supply pipeline; 372. Secondary hot air supply pipeline; 373. Air preheating unit;

[0029] 4. Convection flue; 41. Flow passage;

[0030] 5. Steam-water circulation module; 51. Steam drum; 52. Economizer; 53. Liquid supply pipe; 54. Liquid delivery pipe; 55. Steam-water delivery pipe; 56. Steam supply pipe; 57. Low-temperature superheater; 58. High-temperature superheater. Detailed Implementation

[0031] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, not the entire structure.

[0032] In the description of this utility model, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0033] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0034] In the description of this embodiment, the terms "upper," "lower," "right," and "left," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. In addition, the terms "first" and "second" are only used for distinction in description and have no special meaning.

[0035] The technical solution provided by this utility model will be described below with reference to the accompanying drawings and specific embodiments.

[0036] refer to Figure 1 As shown, this utility model provides a low-rank coal fluidized bed pyrolysis-combustion staged coupling device, which is mainly divided into two reactions, pyrolysis and combustion, which are coupled and connected to each other in a cycle. The device specifically includes a feeding module 1, a fluidized bed pyrolysis furnace module 2 and a fluidized bed combustion furnace module 3.

[0037] In this embodiment, the feeding module 1 is a raw coal conveyor connected to the raw material conveying system. Low-rank raw coal from the raw material conveying system can be orderly conveyed to the fluidized bed pyrolysis furnace module 2 via the closed raw coal conveyor. The fluidized bed pyrolysis furnace module 2 includes a pyrolysis bed and a pyrolysis cyclone separator 22. The pyrolysis bed is connected to the feeding module 1, so that the raw coal can be conveyed to the pyrolysis bed to undergo a pyrolysis reaction and be graded into hot semi-coke and oil gas. The pyrolysis cyclone separator 22 is connected to the pyrolysis bed and is used to separate fine coal powder from the oil gas, so that the fine coal powder can undergo a pyrolysis reaction after continuous heating in the pyrolysis bed. The fluidized bed combustion furnace module 3 includes a combustion bed, and a feeding channel 23 and a return channel 32 are provided in a circulating connection between the combustion bed and the pyrolysis bed. The feeding channel 23 is used to supply hot semi-coke to the combustion bed, where the hot semi-coke can undergo a combustion reaction and generate hot ash. The return channel 32 is used to supply the hot ash to the pyrolysis bed so that the hot ash can form a new solid heat carrier and continue to undergo a pyrolysis reaction with the raw coal.

[0038] In the above configuration, the coal conversion method of this embodiment optimizes the clean coal technology of single coal conversion. By first carbonizing and upgrading the coal before combustion for energy supply, it achieves tiered energy utilization and graded utilization of coal resources, realizing the principle of efficient conversion of low-rank coal resources and improving coal resource conversion efficiency. Preferably, in this embodiment, the particle size of the low-rank coal is less than 10mm, enabling the device to pyrolyze low-rank coal with a particle size of 0-10mm. This method overcomes the shortcomings of traditional pyrolysis methods that can only process lump coal and pulverized coal, thereby saving coal resources. In addition, by interconnecting the materials in the pyrolysis bed and the combustion bed, high-temperature combustion of hot semi-coke, a clean fuel, is achieved in the combustion bed, reducing NOx generation and improving the environmental and economic benefits of the device. Furthermore, this device shortens the fuel transport distance when the pyrolysis and combustion reactions are completely separated into two furnaces. Since there is no intermediate conversion process, the hot semi-coke can directly enter the combustion bed for ignition and combustion, reducing the preheating time and effectively reducing the investment and cost of constructing both fluidized bed pyrolysis furnace module 2 and fluidized bed combustion furnace module 3 at the same time.

[0039] Specifically, in this embodiment, the pyrolysis bed has a pyrolysis boiling section 211 and a pyrolysis suspension section 212 arranged sequentially from bottom to top and connected. The pyrolysis boiling section 211 is used to fill raw coal and hot ash. The pyrolysis suspension section 212 is equipped with a pyrolysis cyclone separator 22. Most of the larger coal particles can be completely pyrolyzed in the pyrolysis boiling section 211, while some of the fine coal powder generated will be blown out of the pyrolysis boiling section 211 by the airflow and enter the pyrolysis suspension section 212. Since the temperature of the pyrolysis suspension section 212 is low, it is difficult for the fine coal powder to undergo a complete pyrolysis reaction. It will be carried out of the fluidized bed pyrolysis furnace module 2 by the oil and gas (pyrolysis raw coal gas) generated by the lower pyrolysis boiling section 211, resulting in excessive dust content in the oil and gas. Therefore, in this embodiment, by setting up a pyrolysis cyclone separation unit 22 in the pyrolysis suspension section 212, fine coal powder is repeatedly separated by the pyrolysis cyclone separation unit 22 and can undergo complete pyrolysis reaction after continuous heating in the pyrolysis bed, thereby realizing the clean and efficient comprehensive utilization of coal resources and achieving the goal of improving the economic and environmental protection of coal resource processing and utilization.

[0040] Preferably, in this embodiment, two pyrolysis cyclone separation units 22 are arranged in parallel within the pyrolysis suspension section 212. The two pyrolysis cyclone separation units 22 can completely cover the area covered by the pyrolysis suspension section 212, and can uniformly and thoroughly separate the fine coal powder in the flue gas, thereby further improving the clean and efficient utilization rate of coal resources.

[0041] In this embodiment, the fluidized bed pyrolysis furnace module 2 further includes a first gas supply unit 24. The first gas supply unit 24 includes a primary hydrogen-rich hot coal gas supply pipeline 241 and a secondary hydrogen-rich hot coal gas supply pipeline 242. One end of the primary hydrogen-rich hot coal gas supply pipeline 241 is connected to one end of the secondary hydrogen-rich hot coal gas supply pipeline 242, so that hydrogen-rich hot coal gas can be supplied to both the primary hydrogen-rich hot coal gas supply pipeline 241 and the secondary hydrogen-rich hot coal gas supply pipeline 242 simultaneously. The other end of the primary hydrogen-rich hot coal gas supply pipeline 241 is connected to the pyrolysis boiling section 211 of the pyrolysis bed and is used to supply primary hydrogen-rich hot coal gas to the pyrolysis bed. Specifically, it can be supplied through an air distribution plate installed inside the pyrolysis bed. The primary hydrogen-rich hot coal gas can lift the coal particles and hot ash from the combustion bed from bottom to top, causing them to tumble and transfer heat and mass, resulting in a pyrolysis reaction. The other end of the secondary hydrogen-rich hot coal gas supply pipeline 242 is connected to the pyrolysis boiling section 211 of the pyrolysis bed, and the connection height between the secondary hydrogen-rich hot coal gas supply pipeline 242 and the pyrolysis bed is higher than that between the primary hydrogen-rich hot coal gas supply pipeline 241 and the pyrolysis bed. The secondary hydrogen-rich hot coal gas supply pipeline 242 can supply secondary hydrogen-rich hot coal gas to the pyrolysis boiling section 211. The role of the secondary hydrogen-rich hot coal gas is to continuously disturb the pyrolysis boiling section 211, intensify the heat and mass transfer process in the boiling section, and make the pyrolysis reaction proceed rapidly.

[0042] In the above configuration, the advantage of providing hydrogen-rich hot coal gas to the pyrolysis boiling section 211 is that the hydrogen-rich hot coal gas can not only provide a hydrogen-rich atmosphere for the pyrolysis reaction and improve the tar yield of the pyrolysis reaction, but also fluidize and continuously disturb the raw coal, so that the raw coal and hot ash can be fully transferred in heat and mass, which facilitates the rapid and continuous pyrolysis reaction. Furthermore, the hydrogen-rich hot coal gas can also serve as a gaseous heat carrier to supply part of the heat to the raw coal, reducing the dependence on solid heat carriers (such as hot ash) and helping to improve the system energy efficiency.

[0043] More specifically, in this embodiment, an oil and gas outlet 25 is also provided at the top of the fluidized bed pyrolysis furnace module 2. The oil and gas outlet 25 can be connected to the pyrolysis suspension section 212, so that the separated oil and gas can be discharged from the oil and gas outlet 25 under the action of the airflow, leaving only the hot semi-coke generated after classification in the pyrolysis bed. This realizes the gradient classification and utilization of coal resources, and also avoids the oil and gas from interfering with the subsequent pyrolysis reaction.

[0044] Specifically, in this embodiment, the combustion bed includes a combustion boiling section 311 and a combustion suspension section 312 arranged sequentially from bottom to top and connected to each other. The combustion boiling section 311 is used to fill hot semi-coke, and the combustion suspension section 312 is used to absorb the flue gas carried up from the combustion boiling section 311 by the airflow. The fluidized bed combustion furnace module 3 also includes a combustion cyclone separation unit 33, which is arranged on one side of the combustion bed. The combustion suspension section 312 and the combustion cyclone separation unit 33 are connected through a flue gas channel 34, and the combustion boiling section 311 and the combustion cyclone separation unit 33 are connected through a return material channel 35. In practical use, a portion of fine coke powder is carried out of the combustion boiling section 311 by the flue gas flow and enters the combustion suspension section 312, where it is suspended and burned. However, due to the low temperature of the combustion suspension section 312, the combustion rate of the fine coke powder particles is low, and the carbon content in the fly ash is high. Therefore, by connecting the upper end of the combustion suspension section 312 to the combustion cyclone separation unit 33 through the flue gas channel 34, the fly ash, fuel (fine coke powder), and desulfurizing agent particles carried out of the combustion bed can be separated by the combustion cyclone separation unit 33 and then recycled back to the combustion boiling section 311 of the combustion bed through the return channel 35. The unburned fine coke powder and desulfurizing agent particles can be reused and continue to participate in the combustion reaction, thereby effectively improving the fuel utilization efficiency of coal resources and further enhancing the economic and environmental benefits of coal resources.

[0045] Furthermore, it should be noted that during the operation of this device, newly generated hot ash particles are added to the pyrolysis bed according to a set ratio and rate. The hot ash generated from the combustion reaction is discharged from the bottom overflow port 36, and a portion of the hot ash enters the pyrolysis boiling section 211 through the return material channel 35, forming a new solid heat carrier that is added to the raw coal to continue participating in the pyrolysis reaction. This completes one cycle of pyrolysis and combustion reactions. Preferably, in this embodiment, the pyrolysis reaction temperature in the pyrolysis bed is controlled between 550℃ and 650℃, and the combustion reaction temperature in the combustion bed is controlled about 200℃ below the deformation temperature of fine coke powder and fly ash, i.e., within 850℃-950℃.

[0046] Preferably, in this embodiment, during installation, the pyrolysis bed can be installed on the civil engineering frame, and the combustion bed can be installed on the boiler steel frame. The combustion bed and the pyrolysis bed are connected by a feeding channel 23 and a return channel 32. In addition, the combustion cyclone separator 33 is installed on the boiler steel frame, with its upper end connected to the upper part of the combustion bed through a flue gas channel 34, and its lower end connected to the lower part of the combustion bed through a return channel 35. With the above configuration, the device not only simplifies the problem of high-temperature transportation of hot semi-coke, eliminating the need for storage and transportation, but also reduces the investment in building storage and transportation facilities. The pyrolysis and combustion processes can be completed on the same civil engineering frame, eliminating the need for building semi-coke storage and transportation facilities. It is easy to realize the integrated modular construction of the fluidized bed pyrolysis furnace module 2 and the fluidized bed combustion furnace module 3, and the entire device can also be skid-mounted.

[0047] More specifically, in this embodiment, the fluidized bed combustion furnace module 3 further includes a second air supply unit 37, which includes a primary hot air supply pipeline 371 and a secondary hot air supply pipeline 372. One end of the primary hot air supply pipeline 371 is connected to one end of the secondary hot air supply pipeline 372 so that hot air can be supplied to both the primary hot air supply pipeline 371 and the secondary hot air supply pipeline 372 at the same time. The other end of the primary hot air supply pipeline 371 is connected to the combustion boiling section 311 of the combustion bed and can provide primary hot air to the combustion boiling section 311. The primary hot air can lift the hot semi-coke newly entering the combustion boiling section 311 from bottom to top and tumble it up and down to make it fluidized. The other end of the secondary hot air supply pipe 372 is also connected to the combustion boiling section 311, and the connection height between the secondary hot air supply pipe 372 and the combustion boiling section 311 is higher than the connection height between the primary hot air supply pipe 371 and the combustion boiling section 311. The secondary hot air supply pipe 372 can provide secondary hot air to the combustion boiling section 311, and the secondary hot air can disturb the combustion reaction.

[0048] In the above setup, the hot semi-coke does not undergo a preheating process in the pyrolysis bed. It can ignite and burn instantly upon encountering hot air supplied from the primary hot air supply pipe 371. At this time, the combustion boiling section 311 is very thick and remains incandescent, equivalent to a large heat storage tank. Secondary hot air can be supplied from multiple air outlets of the combustion bed, which can continuously disturb the combustion boiling section 311, thereby ensuring that the combustion reaction proceeds completely.

[0049] Optionally, the device also includes a convection flue 4, which is vertically arranged on one side of the combustion cyclone separation unit 33. The upper air inlet of the convection flue 4 is connected to the top of the combustion cyclone separation unit 33 through the flow channel 41, so that the separated flue gas can flow smoothly along the convection flue 4 by gravity and inertia, reducing the risk of secondary dust and improving the emission efficiency of flue gas to a certain extent.

[0050] Furthermore, in this embodiment, the second air supply unit 37 also includes an air preheating unit 373 disposed in the convection flue 4. The air inlet of the air preheating unit 373 is connected to the air supply device, and the air outlet of the air preheating unit 373 is connected to the primary hot air supply pipeline 371 and the secondary hot air supply pipeline 372. The air preheating unit 373 is thermally connected to the convection flue 4, so that the cold air output from the air supply device can exchange heat with the high-temperature flue gas in the convection flue 4 in the air preheating unit 373. This not only provides the required hot air for the primary hot air supply pipeline 371 and the secondary hot air supply pipeline 372, but also reduces the flue gas emission temperature so that it can meet the emission temperature standard, and also effectively improves the utilization rate of flue gas heat energy.

[0051] Optionally, refer to Figure 1 As shown, the device also includes a steam-water circulation module 5, which includes a steam drum 51, an economizer 52, a liquid supply pipe 53, a liquid delivery pipe 54, a steam-water delivery pipe 55, and a steam supply pipe 56. The steam drum 51 is used for gas-liquid separation of water vapor, and the top of the steam drum 51 is equipped with a steam exhaust port. The economizer 52 is installed in the convection flue 4. The inlet of the economizer 52 is connected to the water supply device, and the outlet of the economizer 52 is connected to the steam drum 51 through the liquid supply pipe 53. The economizer 52 is thermally connected to the convection flue 4 so that the heat of the flue gas can be transferred to the cold water, and the heated cold water can be transferred to the steam drum 51. One end of the liquid delivery pipe 54 is connected to the steam drum 51, and the other end is connected to the furnace wall cavity inlet of the fluidized bed combustion furnace module 3. The water vapor delivery pipe 55 is connected between the furnace wall cavity outlet of the fluidized bed combustion furnace module 3 and the steam drum 51. The steam supply pipe 56 is connected between the steam exhaust port and the user terminal. The steam after gas-liquid separation can be transferred to the user terminal through the steam exhaust port and the steam supply pipe 56.

[0052] Through the above configuration, the chilled water output from the water supply device can exchange heat with the high-temperature flue gas in the convection flue duct 4 when it passes through the economizer 52, thereby further reducing the temperature of the high-temperature flue gas. Moreover, after heat transfer with the high-temperature flue gas, the temperature of the chilled water can be maintained within the temperature range required for liquid cooling. In other parallel embodiments, a water pump can be installed on the liquid supply pipe 53 to precisely control the water temperature delivered to the steam drum 51 by controlling the water flow rate, ensuring that the water temperature delivered from the steam drum 51 to the furnace wall cavity of the fluidized bed combustion furnace module 3 meets the cooling requirements. Furthermore, the steam generated after heat exchange can be provided to the user terminal for user use, thereby further improving the recovery and utilization rate of flue gas waste heat and reducing energy waste.

[0053] More specifically, the steam-water circulation module 5 provided in this embodiment also includes a low-temperature superheater 57 and a high-temperature superheater 58. Both the low-temperature superheater 57 and the high-temperature superheater 58 are installed on the steam supply pipe 56, and are arranged sequentially along the steam flow direction. The low-temperature superheater 57 is used for primary heating of the steam, and the high-temperature superheater 58 is used for secondary heating of the steam to form superheated steam. By heating the steam in stages, after drying, the steam is heated to form high-parameter superheated steam, thereby achieving the function of driving efficient power generation and meeting the usage requirements under actual operating conditions.

[0054] It should be further explained that, in this embodiment, both the high-temperature superheater 58 and the low-temperature superheater 57 are preferably installed in the convection flue 4, and along the flow direction of the flue gas, the high-temperature superheater 58, the low-temperature superheater 57, the economizer 52, and the air preheating unit 373 are arranged sequentially from top to bottom. In this way, when the high-temperature flue gas flows from top to bottom in the convection flue 4, it will first exchange heat with the steam located in the high-temperature superheater 58, so that the steam can be heated by the high-temperature flue gas and form superheated steam. When it continues to flow downward, it can continue to exchange heat with the steam in the low-temperature superheater 57, so that the low-temperature superheater 57 can heat the steam once. Subsequently, the flue gas continues to exchange heat with the economizer 52 and the air preheating unit 373 to preheat the cold water and cold air respectively. With the above configuration, the device can effectively reduce the temperature of high-temperature flue gas, so that the temperature of high-temperature flue gas can be effectively reduced to the exhaust temperature standard under the cooling effect of high-temperature superheater 58, low-temperature superheater 57, economizer 52 and air preheating unit 373. On the other hand, it can also avoid the additional costs brought by setting up heating equipment, thereby achieving a high environmental protection standard and having better economic benefits.

[0055] In the description of this specification, references to terms such as "some embodiments," "other embodiments," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0056] Obviously, the above embodiments of this utility model are merely examples for clearly illustrating the present utility model, and are not intended to limit the implementation of the present utility model. Those skilled in the art can make various obvious changes, readjustments, and substitutions without departing from the protection scope of this utility model. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the protection scope of the claims of this utility model.

Claims

1. A fluidized bed pyrolysis-combustion staged coupling device for low-rank coal, characterized in that, include: The system comprises a feeding module (1), a fluidized bed pyrolysis furnace module (2), and a fluidized bed combustion furnace module (3), wherein: The feeding module (1) is used to provide raw coal to the fluidized bed pyrolysis furnace module (2); The fluidized bed pyrolysis furnace module (2) includes a pyrolysis bed and a pyrolysis cyclone separator unit (22). The pyrolysis bed is connected to the feeding module (1). The raw coal can undergo pyrolysis reaction in the pyrolysis bed and be graded to generate hot semi-coke and oil gas. The pyrolysis cyclone separator unit (22) is connected to the pyrolysis bed and is used to separate the fine coal powder in the oil gas so that the fine coal powder can undergo pyrolysis reaction after continuous heating in the pyrolysis bed. The fluidized bed combustion furnace module (3) includes a combustion bed. The combustion bed and the pyrolysis bed are circulated and connected by a feeding channel (23) and a return channel (32). The feeding channel (23) is used to supply the hot semi-coke to the combustion bed. The hot semi-coke can undergo a combustion reaction in the combustion bed and generate hot ash. The return channel (32) can supply the hot ash to the pyrolysis bed so that the hot ash can form a new solid heat carrier and continue to undergo a pyrolysis reaction with the raw coal.

2. The low-rank coal fluidized bed pyrolysis-combustion staged coupling device according to claim 1, characterized in that, The pyrolysis bed has a pyrolysis boiling section (211) and a pyrolysis suspension section (212) arranged sequentially from bottom to top and connected. The pyrolysis boiling section (211) is used to fill the raw coal and the hot ash residue. The pyrolysis suspension section (212) is used to absorb the oil and gas. The pyrolysis cyclone separator (22) is provided in the pyrolysis suspension section (212). The particle size of the fine coal powder is smaller than the particle size of the raw coal that undergoes pyrolysis reaction in the pyrolysis boiling section (211).

3. The low-rank coal fluidized bed pyrolysis-combustion staged coupling device according to claim 1, characterized in that, The fluidized bed pyrolysis furnace module (2) further includes a first gas supply unit (24), which includes a primary hydrogen-rich hot coal gas supply pipeline (241) and a secondary hydrogen-rich hot coal gas supply pipeline (242). One end of the primary hydrogen-rich hot coal gas supply pipeline (241) is connected to one end of the secondary hydrogen-rich hot coal gas supply pipeline (242), and the other end of the primary hydrogen-rich hot coal gas supply pipeline (241) is connected to the pyrolysis bed. It is used to supply primary hydrogen-rich hot coal gas to the pyrolysis bed and can lift the raw coal and the hot ash from bottom to top through the primary hydrogen-rich hot coal gas. The other end of the secondary hydrogen-rich hot coal gas supply pipeline (242) is connected to the pyrolysis bed and is higher than the connection height between the primary hydrogen-rich hot coal gas supply pipeline (241) and the pyrolysis bed. The secondary hydrogen-rich hot coal gas supply pipeline (242) is used to supply secondary hydrogen-rich hot coal gas to the pyrolysis bed and can disturb the pyrolysis reaction.

4. The low-rank coal fluidized bed pyrolysis-combustion staged coupling device according to claim 1, characterized in that, The fluidized bed combustion furnace module (3) further includes a second air supply unit (37), which includes a primary hot air supply pipeline (371) and a secondary hot air supply pipeline (372). One end of the primary hot air supply pipeline (371) is connected to one end of the secondary hot air supply pipeline (372), and the other end of the primary hot air supply pipeline (371) is connected to the combustion bed. It is used to supply primary hot air to the combustion bed and can lift the hot semi-coke from bottom to top through the primary hot air, so that the hot semi-coke tumbles up and down and forms a fluidized state. The other end of the secondary hot air supply pipe (372) is connected to the combustion bed and is higher than the connection height between the primary hot air supply pipe (371) and the combustion bed. The secondary hot air supply pipe (372) is used to supply secondary hot air to the combustion bed and can disturb the combustion reaction.

5. The low-rank coal fluidized bed pyrolysis-combustion staged coupling device according to claim 4, characterized in that, The combustion bed includes a combustion boiling section (311) and a combustion suspension section (312) connected sequentially from bottom to top. The combustion boiling section (311) is used to fill the hot semi-coke, and the combustion suspension section (312) is used to absorb the flue gas generated by the combustion reaction. The fluidized bed combustion furnace module (3) further includes a combustion cyclone separation unit (33), which is located on one side of the combustion bed. The combustion suspension section (312) is connected to the combustion cyclone separation unit (33) through a flue gas channel (34), and the combustion boiling section (311) is connected to the combustion cyclone separation unit (33) through a return channel (35). The combustion cyclone separation unit (33) is used to separate fine coke powder and desulfurizing agent particles in the flue gas so that the fine coke powder and the desulfurizing agent particles can return to the combustion boiling section (311) through the return channel (35) and continue to participate in the combustion reaction.

6. The low-rank coal fluidized bed pyrolysis-combustion staged coupling device according to claim 5, characterized in that, It also includes a convection flue (4), which is vertically arranged on one side of the combustion cyclone separation unit (33). The upper air inlet of the convection flue (4) is connected to the top of the combustion cyclone separation unit (33) through the flow passage (41) and is used to discharge the flue gas outward.

7. The low-rank coal fluidized bed pyrolysis-combustion staged coupling device according to claim 6, characterized in that, The second air supply unit (37) further includes an air preheating unit (373) disposed in the convection flue (4). The air inlet of the air preheating unit (373) is connected to the air supply device, and the air outlet of the air preheating unit (373) is connected to one end of the primary hot air supply pipeline (371) and the secondary hot air supply pipeline (372). The air preheating unit (373) is thermally connected to the convection flue (4).

8. The low-rank coal fluidized bed pyrolysis-combustion staged coupling device according to claim 7, characterized in that, It also includes a steam-water circulation module (5), which includes a steam drum (51), an economizer (52), a liquid supply pipe (53), a liquid delivery pipe (54), a water-steam delivery pipe (55), and a steam supply pipe (56). The steam drum (51) is used to separate water vapor into gas and liquid, and the top of the steam drum (51) is provided with a steam exhaust port. The economizer (52) is installed in the convection flue (4). The inlet of the economizer (52) is connected to the water supply device, and the outlet of the economizer (52) is connected to the water supply device. The liquid supply pipe (53) is connected to the steam drum (51), and the economizer (52) is thermally connected to the convection flue (4) so ​​that the heat of the flue gas can be transferred to the cold water and the heated cold water can be transferred to the steam drum (51); one end of the liquid delivery pipe (54) is connected to the steam drum (51), and the other end of the liquid delivery pipe (54) is connected to the furnace wall cavity inlet of the fluidized bed combustion furnace module (3); the water steam delivery pipe (55) is connected between the furnace wall cavity outlet of the fluidized bed combustion furnace module (3) and the steam drum (51); the steam supply pipe (56) is connected between the user terminal and the exhaust port, and the steam after gas-liquid separation can be transferred to the user terminal through the exhaust port and the steam supply pipe (56).

9. The low-rank coal fluidized bed pyrolysis-combustion staged coupling device according to claim 8, characterized in that, The steam-water circulation module (5) further includes a low-temperature superheater (57) and a high-temperature superheater (58). The low-temperature superheater (57) and the high-temperature superheater (58) are both installed on the steam supply pipe (56) and along the flow direction of the steam. The low-temperature superheater (57) and the high-temperature superheater (58) are arranged in sequence. The low-temperature superheater (57) is used to heat the steam in a primary manner, and the high-temperature superheater (58) is used to heat the steam in a secondary manner to form superheated steam.

10. The low-rank coal fluidized bed pyrolysis-combustion staged coupling device according to claim 9, characterized in that, The high-temperature superheater (58) and the low-temperature superheater (57) are both located in the convection flue (4), and along the flow direction of the flue gas, the high-temperature superheater (58), the low-temperature superheater (57), the economizer (52) and the air preheating unit (373) are arranged sequentially from top to bottom.

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