Circulating fluidized bed incineration system for coal gangue combustion

Abstract

The circulating fluidized bed incineration system for coal gangue combustion comprises an incinerator, a gas-solid separation device and an air preheating device, a hearth and an air chamber which are communicated with each other are arranged in the incinerator, and the hearth is provided with a smoke exhaust port and a fly ash inlet; the gas-solid separation device comprises a first-stage separator, a second-stage separator and a return feeder, the first-stage separator and the second-stage separator are arranged in series, a first-stage flue gas inlet of the first-stage separator is communicated with the flue gas discharge outlet, and a first-stage ash outlet of the first-stage separator and a second-stage ash outlet of the second-stage separator are communicated to the fly ash inlet through the return feeder; the air preheating device is provided with a flue gas inlet and a preheated air outlet, the flue gas inlet is communicated with the secondary flue gas outlet of the secondary separator, and the preheated air outlet is communicated with the air chamber, so that air preheated by the air preheating device is conveyed to the air chamber. The coal gangue combustion device can realize efficient combustion of coal gangue, cyclic utilization of fly ash and recovery of flue gas heat, and has the advantages of high combustion efficiency and high energy utilization rate.

Description

Technical Field

[0001] This invention relates to the field of solid waste utilization technology, specifically to a circulating fluidized bed incineration system for coal gangue combustion. Background Technology

[0002] Circulating fluidized bed combustion (CFB) technology, as a highly efficient and clean combustion method, has been widely used in the field of coal gangue treatment. In related technologies, CFB systems for coal gangue combustion employ a primary cyclone separator to separate and filter dust particles from the flue gas. A cyclone separator is a device that uses centrifugal force to separate particles from gas. Its working principle involves the dust-laden gas entering the separator tangentially, where it rotates. The particles, under centrifugal force, move towards the separator wall and separate from the gas, falling into the ash hopper. Although the primary cyclone separator can achieve a certain degree of separation between flue gas and dust particles, some dust particles still escape into the atmosphere with the flue gas. This not only leads to excessive particulate matter concentrations in the emitted flue gas, making it difficult to meet increasingly stringent national and local environmental emission standards, but also pollutes the atmospheric environment and affects air quality. Summary of the Invention

[0003] This invention aims to at least partially solve one of the technical problems in related technologies. To this end, embodiments of this invention propose a circulating fluidized bed incineration system for coal gangue combustion, which can achieve efficient combustion of coal gangue, recycling of fly ash, and recovery of flue gas heat, possessing the advantages of high combustion efficiency and high energy utilization.

[0004] The circulating fluidized bed incineration system for coal gangue combustion provided by this invention includes: An incinerator, wherein the incinerator has a connected furnace chamber and an air chamber, the air chamber is located below the furnace chamber, an air distribution plate is provided between the furnace chamber and the air chamber, and the furnace chamber has a flue gas discharge port and a fly ash inlet; A gas-solid separation device includes a primary separator, a secondary separator, and a return feeder. The primary separator has a primary flue gas inlet, a primary flue gas outlet, and a primary ash outlet. The secondary separator has a secondary flue gas inlet, a secondary flue gas outlet, and a secondary ash outlet. The primary flue gas inlet is connected to the flue gas emission outlet. The primary flue gas outlet is connected to the secondary flue gas inlet. Both the primary and secondary ash outlets are connected to the fly ash inlet of the furnace through the return feeder. An air preheating device has a flue gas inlet and a preheated air outlet. The flue gas inlet is connected to the secondary flue gas outlet of the secondary separator, and the preheated air outlet is connected to the air chamber, so that the air preheated by the air preheating device is delivered to the air chamber.

[0005] In summary, the circulating fluidized bed incineration system for coal gangue combustion provided by this invention achieves efficient combustion of coal gangue, recycling of fly ash, and recovery of flue gas heat through the coordinated operation of the incinerator, gas-solid separation device, and air preheating device. It has the advantages of high combustion efficiency, good environmental protection effect, and high energy utilization rate.

[0006] In some embodiments, the incinerator includes a furnace wall, the outer side of which is provided with a support frame and a cover. The furnace wall is constructed of refractory castable or refractory bricks, and the thickness of the furnace wall is set to 200 to 400 mm.

[0007] In some embodiments, the air distribution plate includes a liquid cooling layer and a heat insulation layer. The liquid cooling layer includes a plurality of liquid cooling pipes arranged in an array. The heat insulation layer is constructed of corundum-mullite refractory castable and has a thickness of 150 to 200 mm.

[0008] In some embodiments, the primary separator includes an involute volute section, the primary flue gas inlet is located in the involute volute section, and the aspect ratio of the primary flue gas inlet is set to 1.2 to 1.5.

[0009] In some embodiments, the primary separator further includes a cylindrical body and a conical body, wherein the involute volute section, the cylindrical body, and the conical body are sequentially connected from top to bottom along the height direction of the incinerator, the inner diameter of the cylindrical body is set to D, the height of the cylindrical body is 1.8D to 2.2D, the height of the conical body is 2.5D to 3.0D, and the cone angle of the conical body is 15° to 20°.

[0010] In some embodiments, the primary separator further includes a ash discharge pipe communicating with the conical cylinder and a plurality of baffles. The plurality of baffles are staggered and arranged inside the ash discharge pipe to form a bent ash discharge channel inside the ash discharge pipe. The end of the ash discharge pipe away from the conical cylinder is provided with a funnel-shaped primary ash outlet.

[0011] In some embodiments, the secondary separator includes a housing, a diversion channel, and a plurality of cyclones. The housing has an installation cavity and a flue gas collection chamber. The secondary flue gas inlet is located on the side wall of the installation cavity, and the secondary flue gas outlet is located on the side wall of the flue gas collection chamber. The plurality of cyclones are evenly arranged in the installation cavity. Each cyclone has a flue gas inlet, a flue gas outlet, and an ash outlet. The two ends of the diversion channel are connected to the secondary flue gas inlet and the flue gas outlet. The flue gas outlet is connected to the flue gas collection chamber, and the ash outlet is connected to the secondary ash outlet.

[0012] In some embodiments, a plurality of the cyclones are arranged at equal intervals along the circumferential direction of the mounting cavity.

[0013] In some embodiments, the cyclone includes an exhaust pipe and a cyclone tube. The exhaust pipe is connected to the flue gas collection chamber. The length of the exhaust pipe inserted into the cyclone tube is 1 / 2 to 2 / 3 of the height of the cyclone tube. The bottom of the exhaust pipe is provided with an inverted conical opening.

[0014] In some embodiments, the air preheating device includes a high-temperature zone and a low-temperature zone connected to each other, wherein the sidewall of the high-temperature zone is made of heat-resistant steel and the low-temperature zone is made of corrosion-resistant material. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of a circulating fluidized bed incineration system for coal gangue combustion provided in an embodiment of the present invention.

[0016] Figure 2 This is a schematic diagram of the structure of a primary separator in a circulating fluidized bed incineration system for coal gangue combustion, provided in an embodiment of the present invention.

[0017] Figure 3 This is a top view schematic diagram of the primary separator in a circulating fluidized bed incineration system for coal gangue combustion provided in an embodiment of the present invention.

[0018] Figure 4 yes Figure 2 A magnified view of a portion of point A in the middle.

[0019] Figure 5 This is a schematic diagram of the structure of a secondary separator in a circulating fluidized bed incineration system for coal gangue combustion, provided in an embodiment of the present invention.

[0020] Figure 6 This is a top view schematic diagram of the secondary separator in a circulating fluidized bed incineration system for coal gangue combustion provided in an embodiment of the present invention.

[0021] Figure 7 yes Figure 5 A magnified view of a portion of point B in the middle.

[0022] Figure label: 11. Incinerator; 111. Furnace chamber; 1111. Flue gas outlet; 1112. Fly ash inlet; 112. Air chamber; 113. Air distribution plate; 13. Gas-solid separation device; 131. Primary separator; 1311. Primary flue gas inlet; 1312. Primary flue gas outlet; 1313. Primary ash outlet; 1314. Involute volute section; 1315. Cylindrical body; 1316. Conical body; 1317. Ash discharge pipe; 1318. Shell insulation layer; 1319. Protective layer; 13191. First insulation layer; 13192. First transition layer; 13193. Working layer; 133. Secondary separator; 1331. Secondary flue gas inlet; 1332. Secondary flue gas outlet; 1333. Secondary ash outlet; 1334. Outer shell; 13341. Outer cover; 13342. Second insulation layer; 13343. Second transition layer; 1335. Diversion channel; 1336. Flue gas collection chamber; 1337. Installation cavity; 135. Return feeder; 137. Cyclone; 1371. Flue gas inlet; 1372. Flue gas outlet; 1373. Ash outlet; 1374. Exhaust pipe; 1375. Cyclone tube; 15. Air preheating device; 151. Flue gas inlet; 152. High temperature zone; 153. Low temperature zone. Detailed Implementation

[0023] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0024] like Figures 1 to 7 As shown, the present invention provides a circulating fluidized bed incineration system for coal gangue combustion, which includes an incinerator 11, a gas-solid separation device 13, and an air preheating device 15. The incinerator 11 has a furnace chamber 111 and an air chamber 112 that are connected to each other. The air chamber 112 is located below the furnace chamber 111. An air distribution plate 113 is provided between the furnace chamber 111 and the air chamber 112. The furnace chamber 111 has a flue gas exhaust port 1111 and a fly ash inlet 1112. The gas-solid separation device 13 includes a primary separator 131, a secondary separator 133, and a return feeder 135. The primary separator 131 has a primary flue gas inlet 1311, a primary flue gas outlet 1312, and a primary ash outlet 1313. The secondary separator 133 has a secondary flue gas inlet 1331, a secondary flue gas outlet 1332, and a secondary ash outlet 1333. The primary flue gas inlet 1311 is connected to the flue gas emission outlet 1111, and the primary flue gas outlet 1312... The primary ash outlet 1313 and the secondary ash outlet 1333 are connected to the fly ash inlet 1112 of the furnace 111 via the return feeder 135. The air preheating device 15 has a flue gas inlet 151 and a preheated air outlet. The flue gas inlet 151 is connected to the secondary flue gas outlet 1332 of the secondary separator 133, and the preheated air outlet is connected to the air chamber 112, so that the air preheated by the air preheating device 15 is delivered to the air chamber 112.

[0025] Specifically, the incinerator 11 is the core combustion equipment of the entire system. It is divided into a furnace 111 and an air chamber 112 by an air distribution plate 113. This allows the air entering through the air chamber 112 to be evenly distributed into the furnace 111, providing a stable airflow environment for the combustion of coal gangue and ensuring complete combustion within the furnace 111. The primary separator 131 and the secondary separator 133 are connected in series via the primary flue gas outlet 1312 and the secondary flue gas inlet 1331. That is, the flue gas containing a large amount of fly ash discharged from the furnace 111 first enters the primary separator 131 through the flue gas outlet 1111 and the primary flue gas inlet 1311. After gas-solid separation in the primary separator 131, the flue gas enters the secondary separator 133 through the primary flue gas outlet 1312 and the secondary flue gas inlet 1331 to separate smaller fly ash particles, further improving the purification level of the flue gas.

[0026] Two return feeders 135 are provided, which are respectively located at the primary ash outlet 1313 and the secondary ash outlet 1333. They re-feed the solid particles formed by the primary separator 131 and the secondary separator 133 back into the furnace 111, realizing the recycling and combustion of fly ash, improving the combustion efficiency of fuel, and reducing the emission of unburned particles.

[0027] The air preheating device 15 is equipped with a heat exchanger, which can use the heat carried by the flue gas discharged from the secondary separator 133 to heat the air. The preheated air is then discharged from the preheated air outlet and connected to the air chamber 112 of the incinerator 11 through a pipeline, thus delivering the preheated air to the air chamber 112. After entering the air chamber 112, the preheated air is then evenly distributed into the furnace 111 through the air distribution plate 113, providing higher-temperature combustion air for the combustion of coal gangue, further improving combustion efficiency, and simultaneously realizing the recovery and utilization of flue gas heat, thus reducing energy consumption.

[0028] In summary, the circulating fluidized bed incineration system for coal gangue combustion provided by the present invention achieves efficient combustion of coal gangue, recycling of fly ash, and recovery of flue gas heat through the coordinated operation of the incinerator 11, the gas-solid separation device 13, and the air preheating device 15. It has the advantages of high combustion efficiency, good environmental protection effect, and high energy utilization rate.

[0029] In some embodiments, the incinerator 11 includes a furnace wall, with a support frame and a casing on the outer side of the furnace wall. The furnace wall is constructed of refractory castable or refractory bricks, and its thickness is set to 200 to 400 mm. The support frame and casing can be made of steel to support the furnace wall and ensure sufficient structural strength. The furnace wall, constructed of refractory castable or refractory bricks, can withstand high pressure and temperature and also has good erosion resistance, resisting the erosion of acidic or alkaline substances produced during the combustion of coal gangue.

[0030] The furnace wall thickness is set at 200 to 400 mm. This ensures sufficient refractory performance and strength to effectively protect the internal structure of the incinerator 11 from high-temperature damage, while also balancing economy and thermal efficiency to achieve optimal operation of the incinerator 11. For example, if the furnace wall thickness is less than 200 mm, its heat capacity under high-temperature conditions is small, making it unable to effectively absorb and disperse high-temperature heat. This can easily lead to excessively high surface temperatures, accelerating the damage and spalling of the refractory material, thus reducing the service life of the furnace wall and affecting the normal operation of the incinerator 11. Conversely, if the furnace wall thickness is greater than 400 mm, although it can further improve refractory performance, it will increase the overall weight and construction cost of the incinerator 11, while also increasing the heat dissipation burden on the furnace wall, reducing the thermal efficiency of the incinerator 11, and hindering the rational use of energy.

[0031] Furthermore, the air distribution plate 113 includes a liquid cooling layer and a heat insulation layer. The liquid cooling layer includes multiple liquid cooling pipes arranged in an array. The heat insulation layer is constructed of corundum-mullite refractory castable, and its thickness is set to 150 to 200 mm, for example, 150 mm, 180 mm, or 200 mm. The heat insulation layer is located on the side of the liquid cooling layer facing the furnace 111, effectively isolating the high-temperature zone 152 from the cooling medium and achieving heat insulation.

[0032] like Figure 2 , Figure 3 and Figure 4 As shown, in some embodiments, the primary separator 131 includes an involute volute section 1314, and the primary flue gas inlet 1311 is located in the involute volute section 1314. The aspect ratio of the primary flue gas inlet 1311 is set to 1.2 to 1.5 to ensure that the flue gas enters the primary separator 131 with the optimal swirling intensity and to avoid coarse particles settling and clogging the primary flue gas inlet 1311.

[0033] In this embodiment, the primary separator 131 is used to capture coarse fly ash particles with a diameter ≥50 micrometers in the flue gas. This portion of fly ash accounts for 60% to 70% of the total ash carried in the flue gas, thus it can undertake the task of coarse separation for the entire system, reducing the processing load on the subsequent secondary separator 133. The cross-section of the primary flue gas inlet 1311 is set to rectangular, the width of the primary flue gas inlet 1311 is set to 800 mm, the height of the primary flue gas inlet 1311 is set to 1000 mm, and the design velocity of the flue gas at the primary flue gas inlet 1311 is set to 18 to 22 m / s to ensure that the flue gas enters the primary separator 131 with optimal swirling intensity, avoiding coarse particle settling and clogging of the primary flue gas inlet 1311.

[0034] Furthermore, the primary separator 131 also includes a cylindrical body 1315 and a conical body 1316. The involute volute section 1314, the cylindrical body 1315, and the conical body 1316 are sequentially connected from top to bottom along the height direction of the incinerator 11. The inner diameter of the cylindrical body 1315 is set as D, and the height of the cylindrical body 1315 is set to 1.8D to 2.2D. On the one hand, it must ensure that the flue gas has sufficient time and space within the cylindrical body 1315 for airflow stabilization and adjustment, so that the rotating airflow entering from the involute volute section 1314 can gradually become stable, avoiding the impact of airflow turbulence on the subsequent separation effect. On the other hand, this height range cannot be too large, otherwise it will increase the overall height and floor space of the equipment, as well as increase the manufacturing cost and operating resistance of the equipment. In this embodiment, the inner diameter of the cylindrical body 1315 is set to 3.2 meters to 3.8 meters.

[0035] The height of the conical cylinder 1316 is 2.5D to 3.0D, which provides ample space and time for the settling of coarse particles. When the flue gas enters the conical cylinder 1316 from the cylindrical cylinder 1315, the airflow velocity increases accordingly as the diameter of the conical cylinder 1316 gradually decreases. At the same time, under the combined action of centrifugal force and gravity, the coarse particles will accelerate their settling along the cylinder wall of the conical cylinder 1316.

[0036] The cone angle of the conical cylinder 1316 is between 15° and 20°, for example, 15°, 18°, and 20°. If the cone angle is too small, although it can provide a gentler settling path, it will result in an excessively long conical cylinder 1316, increasing the size and cost of the equipment. If the cone angle is too large, coarse particles will be subjected to greater impact forces during settling, making them prone to rebound and secondary re-entrainment, thereby reducing separation efficiency.

[0037] Furthermore, the primary separator 131 also includes an ash discharge pipe 1317 connected to the conical cylinder 1316 and multiple baffles. The baffles are staggered within the ash discharge pipe 1317 to form a bent ash discharge channel. The end of the ash discharge pipe 1317 away from the conical cylinder 1316 is provided with a trumpet-shaped primary ash outlet 1313. The combination of the bent ash discharge channel and the trumpet-shaped primary ash outlet 1313 can prevent high-temperature ash in the return feeder 135 from flowing back into the separator under abnormal conditions such as airflow fluctuations, thereby avoiding interference with the normal operation of the separator and ensuring the stability and reliability of the entire system.

[0038] The diameter of the primary ash outlet 1313 is set to 0.25D to 0.3D, which ensures smooth discharge of coarse particles while effectively controlling the airflow velocity at the outlet. This prevents the separated coarse particles from being re-entrained into the airflow due to excessively high airflow velocity, causing secondary segregation and affecting the separation effect. The cone angle of the primary ash outlet 1313 is set to 30°, which allows coarse particles to slide smoothly down the cone surface during discharge, while ensuring smooth connection between the ash discharge pipe 1317 and the external ash discharge system. This reduces problems such as poor ash discharge or ash accumulation caused by excessively large or small cone angles. The distance between the baffle and the primary ash outlet 1313 is set to 50 to 80 mm, which, combined with the funnel-shaped primary ash outlet 1313, prevents secondary segregation of separated coarse particles and prevents high-temperature ash from the return feeder 135 from flowing back into the separator, ensuring ash discharge stability.

[0039] like Figure 2 and Figure 4 As shown, in this embodiment, the primary separator 131 includes a shell insulation layer 1318 and a protective layer 1319. The shell insulation layer 1318 is made of Q235B steel plate, and its thickness is set to 12 to 16 mm. The protective layer 1319 includes a first insulation layer 13191, a first transition layer 13192, and a working layer 13193, which are arranged sequentially from the outside to the inside.

[0040] The first insulation layer 13191 is made of aluminum silicate fiber blanket with a thickness of 100 to 120 mm and a thermal conductivity of ≤0.06 W / (m²). K) (at 200℃), thus effectively reducing heat loss from the casing. The first transition layer 13192 is made of lightweight high-alumina castable with a thickness of 50 to 60 mm and a bulk density of ≤1.8 g / cm³, to alleviate thermal stress caused by the temperature difference between the inside and outside. The working layer 13193 is made of corundum-mullite wear-resistant castable with a thickness of 80 to 100 mm, an Al2O3 (alumina) content of ≥75%, a bulk density of ≥2.6 g / cm³, a room temperature compressive strength of ≥80 MPa, and a wear resistance of ≤8 cm³, which can withstand long-term erosion by fly ash particles and prevent casing wear and leakage.

[0041] Furthermore, the inner walls of the involute volute section 1314 and at least part of the cylindrical section 1315 are lined with corundum ceramic sheets. The thickness of the corundum ceramic sheets is set to 15 to 20 mm, and the size is set to 100×100 mm. The gaps between two adjacent corundum ceramic sheets are filled with high-temperature wear-resistant putty to further improve the wear resistance life of key areas and ensure that the equipment can run continuously for ≥8000 hours without replacing the working layer 13193.

[0042] like Figure 5 , Figure 6 and Figure 7 As shown, in some embodiments, the secondary separator 133 includes a housing 1334, a diversion channel 1335, and a plurality of cyclones 137. The housing 1334 is provided with an installation cavity 1337 and a flue gas collection chamber 1336. The secondary flue gas inlet 1331 is located on the side wall of the installation cavity 1337, and the secondary flue gas outlet 1332 is located on the side wall of the flue gas collection chamber 1336. The plurality of cyclones 137 are evenly arranged in the installation cavity 1337. Each cyclone 137 has a flue gas inlet 1371, a flue gas outlet 1372, and an ash outlet 1373. The two ends of the diversion channel 1335 are connected to the secondary flue gas inlet 1331 and the flue gas outlet 1371. The flue gas outlet 1372 is connected to the flue gas collection chamber 1336, and the ash outlet 1373 is connected to the secondary ash outlet 1333.

[0043] In other words, when the flue gas to be treated enters through the secondary flue gas inlet 1331, it is evenly distributed to the flue gas sub-inlets 1371 of each cyclone separator 137 via the diversion channel 1335, ensuring that each cyclone separator 137 receives an appropriate amount of flue gas for treatment. The flue gas sub-outlets 1372 of each cyclone separator 137 are connected to the flue gas collection chamber 1336. The clean flue gas, after being separated and treated by the cyclones 137, will be collected in the flue gas collection chamber 1336 and then discharged through the secondary flue gas outlet 1332. Simultaneously, the ash outlets 1373 of each cyclone separator 137 are connected to the secondary ash outlet 1333. The separated dust and particulate matter will be centrally discharged through the ash outlets 1373 to the secondary ash outlet 1333 for subsequent collection and treatment.

[0044] Furthermore, multiple cyclones 137 are arranged at equal intervals along the circumference of the mounting cavity 1337, which ensures that the flue gas flow rate, velocity, and particulate matter concentration received by each cyclone 137 are basically the same. This allows each cyclone 137 to operate under similar working conditions, fully utilize its separation performance, and avoid the problem of some cyclones 137 being overloaded or having low separation efficiency due to uneven local flue gas distribution.

[0045] In this embodiment, the outer shell 1334 of the secondary separator 133 adopts a vertical cylindrical structure, which can be made of Q235B steel plate, and the thickness of the outer shell 1334 can be set to 10 to 14 mm. The inner diameter of the outer shell 1334 is set to 2.8 to 3.4 meters, and the height is set to 4.5 to 5.5 meters. The number of cyclones 137 can be set to 16 to 24, for example, 16, 20, or 24. Among them, the multiple cyclones 137 are arranged in a compact hexagonal pattern to maximize the use of the internal space of the shell and improve the separation efficiency per unit volume.

[0046] Furthermore, each cyclone 137 adopts a tangential inlet structure. The material of cyclone 137 can be 310S heat-resistant steel, with a wall thickness of 4 to 6 mm. The inner diameter of cyclone 137 is 150 to 200 mm, and the height is 1200 to 1500 mm. The cylindrical section of cyclone 137 has a height of 600 to 800 mm, the conical section has a height of 500 to 600 mm, and the ash discharge port has a height of 100 to 150 mm. The flue gas inlet 1371 of cyclone 137 has a rectangular cross-section, with a width of 30 to 40 mm and a height of 80 to 100 mm. The wind speed at the flue gas inlet 1371 is designed to be 22 to 26 m / s to ensure sufficient centrifugal force is generated within the cyclone 137 for medium and fine particles.

[0047] Furthermore, the cyclone separator 137 also includes an exhaust pipe 1374 and a cyclone tube 1375. The exhaust pipe 1374 is connected to the flue gas collection chamber 1336. The length of the exhaust pipe 1374 inserted into the cyclone tube 1375 is 1 / 2 to 2 / 3 of the height of the cyclone tube 1375. The bottom of the exhaust pipe 1374 is provided with an inverted conical opening, and the cone angle of the inverted conical opening is set to 45° to reduce particle escape caused by airflow vortices. In this embodiment, the length of the exhaust pipe 1374 is set to 80 to 100 mm.

[0048] Furthermore, in this embodiment, the inner wall of the flue gas collection chamber 1336 can be made of 304 stainless steel. All exhaust pipes 1374 of the cyclones 137 can be welded to the bottom wall of the flue gas collection chamber 1336 to ensure that the flue gas emitted by the cyclones 137 enters the flue gas collection chamber 1336. A conical ash collection box is provided at the bottom of the secondary separator 133, with a semi-cone angle of 25 to 30°. The ash discharge pipes 1317 of the cyclones 137 are all inserted into the conical ash collection box to a depth of 80 to 100 mm.

[0049] In addition, such as Figure 5 and Figure 7 As shown, the outer shell 1334 of the secondary separator 133 includes an outer cover 13341, a second insulation layer 13342, and a second transition layer 13343, which are arranged sequentially from the outer cover 13341 inwards. The second insulation layer 13342 is made of aluminum silicate fiber blanket with a thickness of 80 to 100 mm and a thermal conductivity ≤0.055 W / (m²). K (at 200℃). The second transition layer 13343 is made of lightweight clay castable with a thickness of 40 to 50 mm and a bulk density of ≤1.6 g / cm³. Furthermore, a second insulation layer 13342 and a second transition layer 13343, consistent with the shell, are laid on the outside of the ash collection box to ensure that the equipment surface temperature is ≤60℃ (at an ambient temperature of 25℃), reducing heat loss.

[0050] The inner wall of Cyclone 137 (especially the inlet section, the transition area between the cylindrical section and the conical section) is coated with a wear-resistant coating made of Al2O3 to TiO2 by plasma spraying. The thickness of the wear-resistant coating is 0.3 to 0.5 mm, the hardness is ≥ HV800, and the bonding strength is ≥ 50 MPa. This allows it to withstand the high-speed erosion of medium and fine particles and prevent the wall of Cyclone 137 from wearing thinner.

[0051] The inner wall of the ash collection box is lined with corundum-mullite wear-resistant castable with a thickness of 60 to 80 mm, an Al2O3 content of ≥70%, and a room temperature compressive strength of ≥60 MPa to prevent particles from eroding and damaging the box wall during the ash collection process.

[0052] In some embodiments, the air preheating device 15 includes a high-temperature zone 152 and a low-temperature zone 153 connected to each other. The sidewall of the high-temperature zone 152 is made of heat-resistant steel, such as 310S heat-resistant steel or 304 heat-resistant steel, to ensure reliability and durability in high-temperature environments. Since the low-temperature zone 153 may come into contact with a medium containing a certain amount of moisture and corrosive substances, the low-temperature zone 153 can be made of corrosion-resistant materials, such as Q235B carbon steel or enamel pipe.

[0053] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to 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 invention.

[0054] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0055] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., 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, an electrical connection, or a connection that allows communication between them; 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, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0056] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0057] In this invention, the terms "one embodiment," "some embodiments," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the 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. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0058] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A circulating fluidized bed incineration system for coal gangue combustion, characterized in that, include: An incinerator (11) is provided with a furnace chamber (111) and an air chamber (112) that are connected to each other. The air chamber (112) is located below the furnace chamber (111). An air distribution plate (113) is provided between the furnace chamber (111) and the air chamber (112). The furnace chamber (111) has a flue gas discharge port (1111) and a fly ash inlet (1112). A gas-solid separation device (13) is provided, comprising a primary separator (131), a secondary separator (133), and a return feeder (135). The primary separator (131) has a primary flue gas inlet (1311), a primary flue gas outlet (1312), and a primary ash outlet (1313). The secondary separator (133) has a secondary flue gas inlet (1331), a secondary flue gas outlet (1332), and a secondary ash outlet (1333). The primary flue gas inlet (1311) is connected to the flue gas discharge port (1111). The primary flue gas outlet (1312) is connected to the secondary flue gas inlet (1331). The primary ash outlet (1313) and the secondary ash outlet (1333) are both connected to the fly ash inlet (1112) of the furnace (111) through the return feeder (135). An air preheating device (15) has a flue gas inlet (151) and a preheated air outlet. The flue gas inlet (151) is connected to the secondary flue gas outlet (1332) of the secondary separator (133), and the preheated air outlet is connected to the air chamber (112) so that the air preheated by the air preheating device (15) is delivered to the air chamber (112).

2. The circulating fluidized bed incineration system for coal gangue combustion according to claim 1, characterized in that, The incinerator (11) includes a furnace wall, with a support frame and a cover on the outside of the furnace wall. The furnace wall is constructed of refractory castable or refractory bricks, and the thickness of the furnace wall is set to 200 to 400 mm.

3. The circulating fluidized bed incineration system for coal gangue combustion according to claim 1, characterized in that, The air distribution plate (113) includes a liquid cooling layer and a heat insulation layer. The liquid cooling layer includes multiple liquid cooling pipes arranged in an array. The heat insulation layer is constructed of corundum-mullite refractory castable and has a thickness of 150 to 200 mm.

4. The circulating fluidized bed incineration system for coal gangue combustion according to claim 1, characterized in that, The primary separator (131) includes an involute volute section (1314), and the primary flue gas inlet (1311) is located in the involute volute section (1314). The aspect ratio of the primary flue gas inlet (1311) is set to 1.2 to 1.

5.

5. The circulating fluidized bed incineration system for coal gangue combustion according to claim 4, characterized in that, The primary separator (131) further includes a cylindrical body (1315) and a conical body (1316). The involute volute section (1314), the cylindrical body (1315), and the conical body (1316) are connected sequentially from top to bottom along the height direction of the incinerator (11). The inner diameter of the cylindrical body (1315) is set to D, the height of the cylindrical body (1315) is 1.8D to 2.2D, the height of the conical body (1316) is 2.5D to 3.0D, and the cone angle of the conical body (1316) is 15° to 20°.

6. The circulating fluidized bed incineration system for coal gangue combustion according to claim 5, characterized in that, The primary separator (131) also includes a ash discharge pipe (1317) communicating with the conical cylinder (1316) and multiple baffles. The multiple baffles are staggered and arranged in the ash discharge pipe (1317) to form a bent ash discharge channel in the ash discharge pipe (1317). The end of the ash discharge pipe (1317) away from the conical cylinder (1316) is provided with a trumpet-shaped primary ash outlet (1313).

7. The circulating fluidized bed incineration system for coal gangue combustion according to claim 1, characterized in that, The secondary separator (133) includes a housing (1334), a diversion channel (1335), and multiple cyclones (137). The housing (1334) contains an installation cavity (1337) and a flue gas collection chamber (1336). The secondary flue gas inlet (1331) is located on the side wall of the installation cavity (1337), and the secondary flue gas outlet (1332) is located on the side wall of the flue gas collection chamber (1336). Multiple cyclones (137) are evenly distributed within the housing. Inside the installation cavity (1337), the cyclone (137) has a flue gas inlet (1371), a flue gas outlet (1372), and an ash outlet (1373). The two ends of the diversion channel (1335) are connected to the secondary flue gas inlet (1331) and the flue gas inlet (1371). The flue gas outlet (1372) is connected to the flue gas collection chamber (1336). The ash outlet (1373) is connected to the secondary ash outlet (1333).

8. The circulating fluidized bed incineration system for coal gangue combustion according to claim 7, characterized in that, The plurality of the cyclones (137) are arranged at equal intervals along the circumferential direction of the mounting cavity (1337).

9. The circulating fluidized bed incineration system for coal gangue combustion according to claim 7, characterized in that, The cyclone (137) includes an exhaust pipe (1374) and a cyclone tube (1375). The exhaust pipe (1374) is connected to the flue gas collection chamber (1336). The length of the exhaust pipe (1374) inserted into the cyclone tube (1375) is 1 / 2 to 2 / 3 of the height of the cyclone tube (1375). The bottom of the exhaust pipe (1374) is provided with an inverted conical opening.

10. The circulating fluidized bed combustion system for coal gangue combustion according to any one of claims 1 to 9, characterized in that, The air preheating device (15) includes a high-temperature zone (152) and a low-temperature zone (153) connected to each other. The sidewall of the high-temperature zone (152) is made of heat-resistant steel, and the low-temperature zone (153) is made of corrosion-resistant material.

Images