System for removing dioxin in waste incineration fly ash through online desorption

Abstract

The invention relates to the technical field of waste incineration fly ash treatment, in particular to an online desorption system for removing dioxin in waste incineration fly ash, which comprises a waste incinerator, a feeding device, a gas-ash separating device, a thermal desorption device, an ash collecting device and a high-temperature circulating fan, the feeding device is used for inputting fly ash generated by waste incineration to the thermal desorption device, and a hot air inlet and a hot air outlet of the thermal desorption device communicate with a smoke outlet of the waste incinerator and an air inlet of the gas-ash separation device correspondingly. An air inlet and an air outlet of the high-temperature circulating fan communicate with an air outlet of the gas-ash separation device and an air inlet of the garbage incinerator correspondingly, and an ash outlet of the gas-ash separation device communicates with the ash collecting device. High-temperature flue gas generated by the garbage incinerator exchanges heat with the fly ash entering the thermal desorption device, efficient thermal desorption of the dioxin in the fly ash is achieved, and the dioxin is gasified, discharged from an exhaust port of the gas-ash separation device along with the high-temperature flue gas and fed into the garbage incinerator to be thoroughly burned and removed.

Description

Technical Field

[0001] The invention relates to the technical field of waste incineration fly ash treatment, and in particular to an online desorption system for removing dioxins from waste incineration fly ash. Background Art

[0002] Incineration of domestic waste is the main method of waste disposal in my country, and waste incineration may cause secondary pollution. The fly ash produced by incineration is the main carrier of secondary pollution caused by waste incineration. This is because the fly ash produced by incineration contains toxic and harmful substances such as heavy metals and "dioxins".

[0003] At present, fly ash produced by garbage incineration is usually treated by cement solidification. Cement solidification is to mix fly ash into cement, and hydration reaction occurs under the condition of adding water to form hydrated calcium silicate to solidify and contain heavy metals, reducing the leaching of toxic substances. However, the use of cement solidification to treat fly ash requires a large amount of cement, occupies a large amount of landfill space, and cannot effectively remove the pollution problem of "dioxin". Summary of the invention

[0004] In view of the shortcomings of the prior art, the present invention provides an online desorption system for removing dioxins from waste incineration fly ash, aiming to solve the pollution problem that the existing cement solidification method for treating fly ash requires a large amount of cement, occupies a large amount of landfill space, and cannot effectively remove "dioxins".

[0005] To achieve the above-mentioned purpose, the present invention provides an online desorption system for removing dioxins from fly ash from waste incineration, comprising a waste incinerator, a feeding device, a gas-ash separation device, a thermal desorption device, an ash collection device and a high-temperature circulating fan, wherein the gas-ash separation device is provided with an air inlet, an air outlet and an ash outlet, the thermal desorption device is provided with a hot gas inlet, a hot gas outlet and an ash inlet, the feeding inlet of the feeding device is used to feed fly ash generated by waste incineration, the feeding outlet of the feeding device is communicated with the ash inlet of the thermal desorption device, the hot gas inlet and the hot gas outlet of the thermal desorption device are respectively communicated with the smoke exhaust port of the waste incinerator and the air inlet of the gas-ash separation device, the air outlet of the gas-ash separation device is communicated with the air inlet of the high-temperature circulating fan, the air outlet of the high-temperature circulating fan is communicated with the air inlet of the waste incinerator, and the ash outlet of the gas-ash separation device is communicated with the ash collection device.

[0006] Furthermore, the ash collecting device includes a discharge conveying device and an ash collecting hopper. The feed end of the discharge conveying device is connected to the ash outlet of the gas-ash separation device, and the discharge end of the discharge conveying device is connected to the ash collecting hopper, which is used to convey the fly ash discharged from the ash outlet of the gas-ash separation device into the ash collecting hopper.

[0007] Furthermore, the fly ash fed by the feeding device comes from fly ash generated by a waste incinerator.

[0008] Furthermore, it also includes a fly ash conveying device, the feed end and the discharge end of the fly ash conveying device are respectively connected to the ash outlet of the waste incinerator and the feed inlet of the feeding device, and the fly ash conveying device is used to input the fly ash generated by the waste incinerator into the feeding device.

[0009] Furthermore, the thermal desorption device is an electromagnetic heating screw conveyor, and the electromagnetic heating screw conveyor is a variable frequency speed-regulated electromagnetic heating screw conveyor 4, and the heat exchange time of the fly ash in the electromagnetic heating screw conveyor is 5 to 30 minutes.

[0010] Furthermore, the thermal desorption device is a rotary kiln, the rotary kiln is configured as a variable frequency speed regulating rotary kiln, and the heat exchange time of the fly ash in the rotary kiln is 5 to 30 minutes.

[0011] Furthermore, the thermal desorption device is a thermal desorption airflow duct 41, and the heat exchange time of the fly ash in the thermal desorption airflow duct is 2 to 30 seconds.

[0012] Furthermore, the gas-ash separation device is a high-temperature ceramic dust collector or a high-temperature metal film dust collector.

[0013] Furthermore, the fly ash is heated to greater than or equal to 500° C. after heat exchange with hot flue gas from the waste incinerator in the thermal desorption device.

[0014] Furthermore, the flue gas temperature generated by the waste incinerator is 600-900°C.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] 1. The system for online desorption and removal of dioxins in fly ash from garbage incineration of the present invention utilizes the high-temperature flue gas generated by the existing garbage incinerator to perform heat exchange with the fly ash entering the thermal desorption device. After the high-temperature flue gas heats the fly ash, the dioxins in the fly ash are gasified, thereby realizing efficient thermal desorption of dioxins in the fly ash. At this time, the flue gas after heat exchange contains gaseous dioxins; under the state of negative pressure formed by the high-temperature circulating fan exhausting air, the flue gas and fly ash after heat exchange enter the gas-ash separation device to realize gas-ash separation; after gas-ash separation, the fly ash enters the ash collecting device from the ash outlet of the gas-ash separation device for collection, and the flue gas is sent from the gas outlet of the gas-ash separation device into the garbage incinerator for high-temperature incineration, thereby completely incinerating and removing dioxins.

[0017] 2. The flue gas after heat exchange enters the waste incinerator as the circulating combustion wind of the waste incinerator, which helps the waste incinerator to burn waste and is beneficial to the drying and burning of the waste in the waste incinerator. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram of the structure of a system for online desorption and removal of dioxins from waste incineration fly ash according to Embodiment 1 of the present invention;

[0019] Figure 2 This is a schematic diagram of the structure of a system for online desorption and removal of dioxins from waste incineration fly ash according to the second embodiment of the present invention;

[0020] Figure 3 This is a schematic diagram of the structure of a system for online desorption and removal of dioxins from waste incineration fly ash according to embodiment 3 of the present invention.

[0021] Reference numerals in the accompanying drawings:

[0022] 1. Waste incinerator; 2. Feeding device; 3. Gas-ash separation device; 4. Electromagnetic heating screw conveyor; 40. Rotary kiln; 41. Thermal desorption air flow duct; 5. Ash collection device; 50. Discharging conveying device; 51. Ash collection hopper; 6. High-temperature circulation fan. DETAILED DESCRIPTION

[0023] It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

[0024] In the description of the present invention, it is necessary to understand that the orientations or positional relationships indicated by terms such as "width", "up", "down", "front", "back", "top" and "bottom" are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0025] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "install", "connect", "connect", and "set" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, a direct connection, or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0026] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0027] Embodiment 1

[0028] Please refer to Figure 1 The present invention provides an online desorption system for removing dioxins from waste incineration fly ash, comprising a waste incinerator 1, a fly ash conveying device, a feeding device 2, a gas-ash separation device 3, a thermal desorption device, an ash collecting device 5 and a high-temperature circulating fan 6. Among them, the feed end and the discharge end of the fly ash conveying device (not shown) are respectively connected with the ash outlet of the waste incinerator 1 and the feed port of the feeding device 2, and the fly ash conveying device is used to input the fly ash generated by the waste incinerator 1 into the feeding device 2; the discharge port of the feeding device 2 is connected with the ash inlet of the thermal desorption device, and the feeding device 2 is used to feed the fly ash generated by the incineration of waste incinerator 1; the hot gas inlet and the hot gas outlet of the thermal desorption device are respectively connected with the smoke exhaust port of the waste incinerator 1 and the air inlet of the gas-ash separation device 3, the air outlet of the gas-ash separation device 3 is connected with the air inlet of the high-temperature circulation fan 6, the air outlet of the high-temperature circulation fan 6 is connected with the air inlet of the waste incinerator 1, and the ash outlet of the gas-ash separation device 3 is connected with the ash collecting device 5.

[0029] The waste incinerator 1 of this embodiment adopts an existing waste incinerator. The flue gas temperature generated by the waste incinerator 1 of this embodiment when burning waste is 600-900°C, specifically 900°C. In other embodiments, the flue gas temperature generated by the waste incinerator 1 when burning waste can also be 600°C or 800°C.

[0030] The feeding device 2 of this embodiment adopts a feeding hopper, which is conducive to the feeding of fly ash. Of course, in other embodiments, the feeding device 2 can also be a feeding cylinder, which is not limited here.

[0031] The fly ash conveying device of this embodiment is a pneumatic conveyor. Of course, in other embodiments, the fly ash conveying device can also be a screw conveyor, which is not limited here. Among them, the pneumatic conveyor belongs to the prior art, and its specific working principle is not described here.

[0032] The gas-ash separation device 3 of this embodiment is a high-temperature metal film dust collector. Of course, in other embodiments, the gas-ash separation device 3 can also be a high-temperature ceramic dust collector, which is not limited here. Among them, the high-temperature metal film dust collector belongs to the prior art, and its specific working principle is not described here.

[0033] The thermal desorption device of this embodiment is an electromagnetic heating screw conveyor 4, which is a variable frequency speed electromagnetic heating screw conveyor 4, so that the electromagnetic heating screw conveyor 4 can adjust the speed of conveying fly ash. It should be noted that since the electromagnetic heating screw conveyor 4 belongs to an existing structure, its specific working principle will not be described in detail here.

[0034] The ash collecting device 5 of this embodiment includes a discharge conveying device 50 and an ash collecting hopper 51. The feed end of the discharge conveying device 50 is connected to the ash outlet of the gas-ash separation device 3, and the discharge end of the discharge conveying device 50 is connected to the ash collecting hopper 51, which is used to convey the fly ash discharged from the ash outlet of the gas-ash separation device 3 into the ash collecting hopper 51. The structure of the discharge conveying device 50 of this embodiment is the same as that of the fly ash conveying device, and will not be described in detail here.

[0035] Of course, in other embodiments, the discharge conveying device 50 may also be a screw conveyor.

[0036] In summary, it can be understood that the fly ash generated by the waste incinerator 1 is directly transported into the feeding device 2 through the fly ash conveying device, and then enters the electromagnetic heating screw conveyor 4 to exchange heat with the high-temperature flue gas generated by the burning of waste in the waste incinerator 1. The temperature of the high-temperature flue gas is 600-900°C (determined by the control of the waste incinerator 1), and the heat exchange time between the high-temperature flue gas and the fly ash in the electromagnetic heating screw conveyor 4 is 5-30 minutes; the fly ash is heated to ≥500°C after heat exchange with the hot flue gas from the waste incinerator 1 in the electromagnetic heating screw conveyor 4, and the high-temperature flue gas and the fly ash are heated to ≥500°C. After the thermal desorption spiral mixing, the dioxins in the fly ash are gasified, and the efficient thermal desorption of dioxins in the fly ash is achieved. At this time, the flue gas after heat exchange contains dioxins in the gas phase; under the state of negative pressure formed by the high-temperature circulation fan 6 exhausting air, the flue gas and fly ash after heat exchange enter the high-temperature metal film dust collector to achieve gas-ash separation; after gas-ash separation, the fly ash enters the discharge conveying device 50 from the ash outlet of the gas-ash separation device 3, and is transported by the discharge conveying device 50 into the ash collecting hopper 51 for collection, and the flue gas is sent from the gas outlet of the gas-ash separation device 3 into the garbage incinerator 1 for high-temperature incineration, so as to completely burn and remove dioxins.

[0037] As an application scenario, the fly ash generated by the waste incinerator 1 is directly transported into the feeding device 2 through the fly ash conveying device, and then enters the electromagnetic heating screw conveyor 4 to exchange heat with the high-temperature flue gas generated by the burning of waste in the waste incinerator 1. The temperature of the high-temperature flue gas is 900°C, and the heat exchange time between the high-temperature flue gas and the fly ash in the electromagnetic heating screw conveyor 4 is 30 minutes; the fly ash is heated to 500°C after heat exchange with the hot flue gas from the waste incinerator 1 in the electromagnetic heating screw conveyor 4, and the high-temperature flue gas and fly ash are mixed in the thermal desorption spiral. The dioxins in the ash are gasified, and efficient thermal desorption of dioxins in the fly ash is achieved. At this time, the flue gas after heat exchange contains dioxins in the gas phase; under the state of negative pressure formed by the high-temperature circulating fan 6 exhausting air, the flue gas and fly ash after heat exchange enter the high-temperature metal film dust collector to achieve gas-ash separation; after gas-ash separation, the fly ash enters the discharge conveying device 50 from the ash outlet of the high-temperature metal film dust collector, and is transported by the discharge conveying device 50 into the ash collecting hopper 51 for collection, and the flue gas is sent from the gas outlet of the high-temperature metal film dust collector into the garbage incinerator 1 for high-temperature incineration, so as to completely burn and remove dioxins.

[0038] As another application scenario, the fly ash generated by the waste incinerator 1 is directly transported into the feeding device 2 through the fly ash conveying device, and then enters the electromagnetic heating screw conveyor 4 to exchange heat with the high-temperature flue gas generated by the burning of waste in the waste incinerator 1. The temperature of the high-temperature flue gas is 600°C, and the heat exchange time between the high-temperature flue gas and the fly ash in the electromagnetic heating screw conveyor 4 is 5 minutes; the fly ash is heated to 550°C after heat exchange with the hot flue gas from the waste incinerator 1 in the electromagnetic heating screw conveyor 4, and the high-temperature flue gas and fly ash are mixed in the thermal desorption spiral. The dioxins in the fly ash are gasified, and efficient thermal desorption of dioxins in the fly ash is achieved. At this time, the flue gas after heat exchange contains dioxins in the gas phase; under the state of negative pressure formed by the high-temperature circulating fan 6 exhausting air, the flue gas and fly ash after heat exchange enter the high-temperature metal film dust collector to achieve gas-ash separation; after gas-ash separation, the fly ash enters the discharge conveying device 50 from the ash outlet of the high-temperature metal film dust collector, and is transported by the discharge conveying device 50 into the ash collecting hopper 51 for collection, and the flue gas is sent from the gas outlet of the high-temperature metal film dust collector into the garbage incinerator 1 for high-temperature incineration, so as to completely burn and remove dioxins.

[0039] It should be noted that the high-temperature flue gas generated by the waste incinerator 1 burning waste does not contain dioxins, the fly ash generated by the waste incinerator 1 burning waste is discharged from the ash outlet of the waste incinerator 1, and the high-temperature flue gas generated by the waste incinerator 1 burning waste is discharged from the exhaust port. In this embodiment, the high-temperature flue gas discharged from the exhaust port of the waste incinerator 1 is divided into two parts, one part is treated by the flue gas purification system and then discharged in compliance with the standards, and the other part is used as a heat source for heat exchange with the fly ash entering the thermal desorption device.

[0040] The system for removing dioxins from fly ash from garbage incineration by online desorption of the present invention makes full use of the resources of the existing garbage incinerator 1, removes dioxins from the fly ash from the garbage incinerator 1, and improves the resource utilization rate of the garbage incinerator 1. In addition, the flue gas after heat exchange enters the garbage incinerator 1 as the circulating combustion wind of the garbage incinerator 1, plays a role in assisting the garbage incinerator 1 to burn garbage, and is beneficial to the drying and burning of the garbage in the garbage incinerator 1. In addition, the fly ash fed by the feeding device 2 comes from the fly ash generated by the incineration of garbage in the garbage incinerator 1, achieving the effect of online desorption to remove dioxins from the fly ash from garbage incineration.

[0041] It should be noted that the high-temperature metal film dust collector not only plays a dust removal role in the system of the present invention, but also can achieve the purpose of solid-gas separation.

[0042] Principle of dioxin desorption: Dioxin is a toxic organic substance with a boiling point of 300-500°C. Dioxin in fly ash is adsorbed in fly ash particles in solid form. When the fly ash is heated to the corresponding temperature, the dioxin particles will "gasify" and migrate to the gas phase, achieving the purpose of dioxin desorption in fly ash.

[0043] At present, the existing high-temperature combustion method is also used to treat dioxins in fly ash from garbage incineration, but the existing high-temperature combustion method for treating dioxins in fly ash from garbage incineration is usually treated by a multi-stage cyclone separator, such as a device for treating fly ash disclosed in patent announcement number: CN215523357U, which includes a multi-stage cyclone separator, each stage of the cyclone separator has the functions of gas-solid mixing, heat exchange and gas-solid separation at the same time, and the heated flue gas is introduced into the flue gas inlet of the final cyclone separator, and the flue gas enters from bottom to top, heating the fly ash entering from top to bottom in the cyclone separator, and the "dioxin" in the fly ash is pyrolyzed and gasified at high temperature, effectively removing the "dioxin" in the fly ash. However, the use of a multi-stage cyclone separator to treat dioxins in fly ash has at least the following defects: the fly ash needs to pass through the cyclone separators of each stage from top to bottom in sequence, and the fly ash with uneven particle size distribution, low density or high viscosity is easy to accumulate inside the cyclone separators of each stage, which is easy to cause the cyclone separator to be blocked, affecting the treatment efficiency of the fly ash. In the system for removing dioxins from fly ash by online desorption in this embodiment, the waste incinerator 1 is mainly used to remove dioxins from fly ash. It can be seen that the use of a multi-stage cyclone separator to treat dioxins in fly ash is obviously not as effective as the system of the present invention in removing dioxins from fly ash.

[0044] The online system for desorbing dioxins from waste incineration fly ash of the present invention can be used as a conventional configuration of a waste incineration power plant. After being treated by the system, the dioxin index in the raw ash produced by waste incineration can meet the regulatory requirements. Subsequently, only water washing and desalination are required to achieve fly ash modification and utilization as general solid waste, thereby greatly reducing the investment and operating costs of harmless disposal and resource utilization of fly ash.

[0045] Embodiment 2

[0046] The difference between this embodiment and the first embodiment is that the structure of the thermal desorption device is different.

[0047] Please refer to Figure 2 The thermal desorption device is a rotary kiln 40, and the rotary kiln 40 is set as a variable frequency speed regulating rotary kiln 40. The heat exchange time of the fly ash in the rotary kiln 40 is 5 to 30 minutes. In this embodiment, the heat exchange time of the fly ash in the rotary kiln 40 is 30 minutes, which can greatly improve the thermal desorption efficiency of dioxins in the fly ash.

[0048] In other embodiments, the heat exchange time of the fly ash in the rotary kiln 40 may also be 5 minutes.

[0049] Specifically, as an application scenario, the high-temperature flue gas generated by the incineration of garbage in the garbage incinerator 1 is introduced into the air inlet of the rotary kiln 40. The temperature of the high-temperature flue gas is 900°C. After the high-temperature flue gas is mixed with fly ash, the high-temperature flue gas heats the fly ash. The heat source for the heating of the fly ash comes from the direct heat transfer of the high-temperature flue gas, and the temperature of the fly ash rises to 500°C. After the flue gas and fly ash are mixed and heat exchanged in the rotary kiln 40, the frequency conversion speed regulation of the rotary kiln 40 is controlled to make the fly ash stay in the rotary kiln 40 for 30 minutes. After the high-temperature flue gas and fly ash are mixed in the rotary kiln 40, the high-temperature circulating fan 6 draws air to form a negative pressure and sends it to the high-temperature metal film dust collector to achieve gas-ash separation. After the gas-ash separation, the fly ash enters the discharge conveying device 50 from the ash outlet of the gas-ash separation device 3 and is transported by the discharge conveying device 50 into the ash collecting hopper 51 for collection. The flue gas is sent from the gas outlet of the gas-ash separation device 3 to the garbage incinerator 1 for high-temperature incineration, and dioxins are completely incinerated and removed.

[0050] As another application scenario, the high-temperature flue gas generated by the incineration of garbage in the garbage incinerator 1 is introduced into the air inlet of the rotary kiln 40. The temperature of the high-temperature flue gas is 600°C. After the high-temperature flue gas is mixed with fly ash, the high-temperature flue gas heats the fly ash. The heat source for the heating of the fly ash comes from the direct heat transfer of the high-temperature flue gas, and the temperature of the fly ash rises to 550°C. After the flue gas and fly ash are mixed and heat exchanged in the rotary kiln 40, the frequency conversion speed regulation of the rotary kiln 40 is controlled to make the fly ash stay in the rotary kiln 40 for 2 minutes. After the high-temperature flue gas and fly ash are mixed in the rotary kiln 40, the high-temperature circulating fan 6 draws air to form a negative pressure and sends it to the high-temperature metal film dust collector to achieve gas-ash separation. After the gas-ash separation, the fly ash enters the discharge conveying device 50 from the ash outlet of the gas-ash separation device 3 and is transported by the discharge conveying device 50 into the ash collecting hopper 51 for collection. The flue gas is sent from the gas outlet of the gas-ash separation device 3 to the garbage incinerator 1 for high-temperature incineration, and dioxins are completely incinerated and removed.

[0051] Embodiment 3

[0052] The difference between this embodiment and the above-mentioned embodiments is that the structure of the thermal desorption device is different.

[0053] Please refer to Figure 3 The thermal desorption device is a thermal desorption airflow duct 41, and the heat exchange time of the fly ash in the thermal desorption airflow duct 41 is 2 to 30 seconds. In this embodiment, the heat exchange time of the fly ash in the thermal desorption airflow duct 41 is 30 seconds. In other embodiments, the heat exchange time of the fly ash in the thermal desorption airflow duct 41 is 2 seconds.

[0054] The flue gas flow velocity in the thermal desorption gas flow duct 41 is 4-10 m / s. In this embodiment, the flue gas flow velocity in the thermal desorption gas flow duct 41 is 4 m / s; in other embodiments, the flue gas flow velocity in the thermal desorption gas flow duct 41 is 10 m / s.

[0055] Specifically, as an application scenario, the high-temperature flue gas generated by the incineration of garbage in the garbage incinerator 1 is introduced into the air inlet of the thermal desorption airflow duct 41. The temperature of the high-temperature flue gas is 900°C. After the high-temperature flue gas is mixed with fly ash, the high-temperature flue gas heats the fly ash. The heat source for the heating of the fly ash comes from the direct heat transfer of the high-temperature flue gas, and the fly ash is heated to 550°C; the flue gas flow rate in the thermal desorption airflow duct 41 is 10m / s; the residence time of the fly ash in the thermal desorption airflow duct 41 is 30s. After the flue gas and fly ash are fully mixed and heat exchanged in the thermal desorption airflow duct 41, they are exhausted by the high-temperature circulating fan 6 to form a negative pressure and are sent to the high-temperature metal film dust collector to achieve gas-ash separation. After the gas-ash separation, the fly ash enters the discharge conveying device 50 from the ash outlet of the gas-ash separation device 3 and is transported by the discharge conveying device 50 into the ash collecting hopper 51 for collection. The flue gas is sent from the air outlet of the gas-ash separation device 3 into the garbage incinerator 1 for high-temperature incineration, and dioxins are completely burned and removed.

[0056] As another application scenario, the high-temperature flue gas generated by the incineration of garbage in the garbage incinerator 1 is introduced into the air inlet of the thermal desorption airflow duct 41. The temperature of the high-temperature flue gas is 600°C. After the high-temperature flue gas is mixed with fly ash, the high-temperature flue gas heats the fly ash. The heat source for the heating of the fly ash comes from the direct heat transfer of the high-temperature flue gas, and the fly ash is heated to 500°C; the flue gas flow rate in the thermal desorption airflow duct 41 is 4m / s; the residence time of the fly ash in the thermal desorption airflow duct 41 is 2s. After the flue gas and fly ash are fully mixed and heat exchanged in the thermal desorption airflow duct 41, they are exhausted by the high-temperature circulating fan 6 to form a negative pressure and are sent to the high-temperature metal film dust collector to achieve gas-ash separation. After the gas-ash separation, the fly ash enters the discharge conveying device 50 from the ash outlet of the gas-ash separation device 3 and is transported by the discharge conveying device 50 into the ash collecting hopper 51 for collection. The flue gas is sent from the air outlet of the gas-ash separation device 3 into the garbage incinerator 1 for high-temperature incineration, and dioxins are completely burned and removed.

[0057] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. An online desorption system for removing dioxins from waste incineration fly ash, characterized in that: It includes a waste incinerator, a feeding device, a gas-ash separation device, a thermal desorption device, an ash collection device and a high-temperature circulating fan. The gas-ash separation device is provided with an air inlet, an air outlet and an ash outlet. The thermal desorption device is provided with a hot gas inlet, a hot gas outlet and an ash inlet. The feeding port of the feeding device is used to feed fly ash generated by waste incineration. The feeding port of the feeding device is connected with the ash inlet of the thermal desorption device. The hot gas inlet and the hot gas outlet of the thermal desorption device are respectively connected with the smoke exhaust port of the waste incinerator and the air inlet of the gas-ash separation device. The air outlet of the gas-ash separation device is connected with the air inlet of the high-temperature circulating fan. The air outlet of the high-temperature circulating fan is connected with the air inlet of the waste incinerator. The ash outlet of the gas-ash separation device is connected with the ash collection device.

2. The system for online desorption and removal of dioxins from waste incineration fly ash according to claim 1, characterized in that: The ash collecting device includes a discharge conveying device and an ash collecting hopper. The feed end of the discharge conveying device is connected to the ash outlet of the gas-ash separation device, and the discharge end of the discharge conveying device is connected to the ash collecting hopper, which is used to convey the fly ash discharged from the ash outlet of the gas-ash separation device into the ash collecting hopper.

3. The system for online desorption and removal of dioxins from waste incineration fly ash according to claim 1, characterized in that: The fly ash fed by the feeding device comes from the fly ash produced by the garbage incinerator.

4. The system for online desorption and removal of dioxins from waste incineration fly ash according to claim 3, characterized in that: It also includes a fly ash conveying device, the feed end and the discharge end of the fly ash conveying device are respectively connected to the ash outlet of the waste incinerator and the feed inlet of the feeding device, and the fly ash conveying device is used to input the fly ash generated by the waste incinerator into the feeding device.

5. A system for online desorption and removal of dioxins from waste incineration fly ash according to any one of claims 1 to 4, characterized in that: The thermal desorption device is an electromagnetic heating screw conveyor, which is a variable frequency speed electromagnetic heating screw conveyor, and the heat exchange time of the fly ash in the electromagnetic heating screw conveyor is 5 to 30 minutes.

6. A system for online desorption and removal of dioxins from waste incineration fly ash according to any one of claims 1 to 4, characterized in that: The thermal desorption device is a rotary kiln, and the rotary kiln is configured as a variable frequency speed regulating rotary kiln. The heat exchange time of the fly ash in the rotary kiln is 5 to 30 minutes.

7. A system for online desorption and removal of dioxins from waste incineration fly ash according to any one of claims 1 to 4, characterized in that: The thermal desorption device is a thermal desorption airflow duct, and the heat exchange time of the fly ash in the thermal desorption airflow duct is 2 to 30 seconds.

8. The system for online desorption and removal of dioxins from waste incineration fly ash according to claim 1, characterized in that: The gas-ash separation device is a high-temperature ceramic dust collector or a high-temperature metal film dust collector.

9. The system for online desorption and removal of dioxins from waste incineration fly ash according to claim 1, characterized in that: The fly ash is heated to greater than or equal to 500° C. after heat exchange with hot flue gas from the waste incinerator in the thermal desorption device.

10. The system for online desorption and removal of dioxins from waste incineration fly ash according to claim 1, characterized in that: The flue gas temperature generated by the waste incinerator is 600-900°C.

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