A plasma melting disposal system and method for municipal solid waste incineration fly ash

Abstract

The present invention belongs to the technical field of solid waste treatment and disposal, and relates to a waste incineration fly ash plasma melting disposal system and a treatment method, including a fly ash temporary storage bin, a pneumatic conveying system, a pelletizing system, a feeding system, a buffer bin, a plasma melting furnace, a flue gas cooler, an induced draft fan and a waste incinerator that are connected in sequence in a closed manner, and the air outlet of the induced draft fan is closed and connected to the secondary air duct of the waste incinerator; it also includes a solvent warehouse, and the solvent warehouse is closed and connected to the feeding system; the fly ash temporary storage bin is used to receive the fly ash generated by the waste incinerator, and a plasma torch is provided at the top of the plasma melting furnace, and a flame injection area is provided at the glass overflow port at the bottom of the plasma melting furnace. The present invention directly quenches the generated flue gas synthesis gas, and then returns the secondary air duct to the waste incinerator. On the one hand, the waste incinerator can be used to remove the combustible gas therein, strengthen the mixing of the flue gas in the furnace, and adjust the temperature field in the furnace.

Description

Technical Field

[0001] The invention belongs to the technical field of solid waste treatment and disposal, and specifically relates to a waste incineration fly ash plasma melting disposal system and disposal method. Background Art

[0002] Waste incineration power generation has gradually become the mainstream method of domestic waste disposal in my country because of its advantages of obvious reduction, less land resources occupied and energy conversion. Waste incineration fly ash (hereinafter referred to as fly ash) is a powdery substance collected by the waste incineration flue gas purification system and is a hazardous waste. Fly ash contains organic pollutants such as benzopyrene, benzanthracene, dioxins and heavy metals such as Cr, Cd, Hg, Pb, Cu, Ni, and is a highly dangerous solid waste. Dioxins are chlorinated tricyclic aromatic hydrocarbon organic compounds with multiple toxic effects, which are irreversible teratogenic, carcinogenic and mutagenic; Hg and its compounds are extremely neurotoxic and can cause serious damage to multiple organs of the human body. If fly ash is not properly disposed of, it will cause serious harm to the environment. my country's large and medium-sized cities have a large amount of fly ash produced and land resources are scarce, and the disposal method mainly based on landfill is facing increasing pressure. Plasma melting technology is to add additives to fly ash or a mixture of raw materials such as solid waste, and then use the heat source generated by a plasma torch to heat the fly ash to an ultra-high temperature. At this time, the activity energy of the elementary particles is far greater than the effect of any intermolecular chemical bonds. The microscopic movement of matter is mainly atomic thermal motion. The original matter is broken into atomic matter to destroy harmful components or make them lose their vitality, thereby converting complex substances into simple harmless substances. In the existing technology, the flue gas discharged from the plasma melting furnace is directly introduced into the secondary combustion chamber at high temperature, and mixed with air or oxygen to burn to remove CO and CH in the tail gas. 4 However, this method is not conducive to resource recycling and is prone to produce positive pressure, affecting the stability of the plasma melting system. Summary of the invention

[0003] In order to overcome the problems of the above-mentioned prior art, the present invention provides a waste incineration fly ash plasma melting disposal system and disposal method which can safely and effectively treat fly ash and can reasonably utilize it as a resource. Fly ash refers to bottom slag and fly ash generated in the disposal processes of domestic waste incineration fly ash, hazardous waste incineration, pyrolysis, etc. (excluding bottom slag generated by medical waste incineration disposal) and waste glassy matter and fly ash generated after hazardous waste plasma, high-temperature melting, etc. disposal.

[0004] In order to achieve the purpose of the present invention, the technical scheme adopted is: a waste incineration fly ash plasma melting treatment system, including a fly ash temporary storage bin, a pneumatic conveying system, a pelletizing system, a feeding system, a buffer bin, a plasma melting furnace, a flue gas cooler, an induced draft fan and a waste incinerator which are sequentially connected in a closed manner, and the air outlet of the induced draft fan is tightly connected to the secondary air duct of the waste incinerator; it also includes a solvent warehouse, which is tightly connected to the feeding system; the fly ash temporary storage bin is used to receive the fly ash generated by the waste incinerator;

[0005] The top of the plasma melting furnace is provided with a plasma torch and a first smoke exhaust pipe which are staggered with each other. The plasma melting furnace is also provided with a glass overflow port and a molten heavy metal discharge port. The glass overflow port is located higher than the molten heavy metal discharge port, and the molten heavy metal discharge port is located at the bottom of the plasma melting furnace. The glass overflow port is also connected with a gas inlet pipe and a second smoke exhaust pipe. One end of the gas inlet pipe located at the glass overflow port is used as a flame injection zone. The gas outlet ends of the first smoke exhaust pipe and the second smoke exhaust pipe are tightly connected to the gas inlet end of the induced draft fan, that is, the first smoke exhaust pipe and the second smoke exhaust pipe are tightly connected to the secondary air duct of the waste incinerator through the induced draft fan.

[0006] The waste incineration fly ash plasma melting treatment method is implemented by a waste incineration fly ash plasma melting treatment system, and the treatment method specifically includes the following steps:

[0007] 1) Collect fly ash generated by the waste incinerator, transport it to the pelletizing system through the pneumatic conveying system for pelletizing, and then send it to the feeding system;

[0008] 2) The solvent in the solvent tank is sent to the feed system, mixed with the fly ash pellets in the feed system, and then sent to the buffer tank; by adding the solvent, the SiO 2 The content is greater than 25% (by weight) and the CaO content is greater than 45% (by weight) to ensure the stable operation of the glass body and reduce the thermal loss rate of the incineration residue;

[0009] 3) The buffer bin is provided with an under-bin feeder for quantitative feeding. The mixture of fly ash pellets and co-solvent in the buffer bin is quantitatively fed into the plasma melting furnace through the quantitative feeder. The organic matter in the fly ash pellets is gasified and cracked to form synthesis gas and discharged through the first exhaust pipe. The inorganic matter is melted into glass and overflows through the glass overflow port. The molten heavy metal in the glass is discharged through the molten heavy metal drain port. The flame spraying area is in a burning state to remove the toxic and combustible gas in the flue gas synthesis gas at the glass overflow port and strengthen the further combustion of the unburned matter in the glass, thereby reducing the generation of dioxins. Then the flue gas synthesis gas is discharged through the second exhaust pipe;

[0010] 4) Under the action of the induced draft fan, the flue gas synthesis gas discharged from the first exhaust pipe and the second exhaust pipe merges and enters the flue gas cooler. After being cooled, the flue gas enters the waste incinerator through the secondary air duct of the waste incinerator.

[0011] Preferably, in step 1), the pellet size is 10-15 mm, and the water content is less than 30% (by weight). In step 3), the temperature in the plasma melting furnace is controlled at 1450-1600°C, which ensures that the time from the gasification and cracking of the fly ash pellets entering the plasma melting furnace to the flue gas outlet is at least 2 seconds, and on the other hand, it can ensure that the fly ash pellets are completely burned.

[0012] Preferably, the solvent in step 2) is limestone and quartz sand, and the amount of addition is such that SiO 2 The content is greater than 25% (by weight) and the CaO content is greater than 45% (by weight) to ensure the stable operation of the glass body while reducing the thermal loss rate of the incineration residue, and effectively reducing the viscosity of the glass body and improving fluidity.

[0013] Compared with the prior art, the present application achieves the following beneficial effects: the setting of the secondary combustion chamber of the prior art is omitted, and the generated flue gas synthesis gas is directly quenched, and then the secondary air duct is returned to the waste incinerator. On the one hand, the waste incinerator can be used to remove the combustible gas therein, enhance the mixing of the flue gas in the furnace and adjust the temperature field in the furnace. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of a waste incineration fly ash plasma melting treatment system in an embodiment of the present invention.

[0015] Figure 2 Schematic diagram of the structure of a plasma melting furnace in an embodiment of the present invention.

[0016] In the figure, 1. Under-bin feeder, 2. Molten heavy metal discharge port, 3. Plasma torch, 4. First smoke exhaust pipe, 5. Second smoke exhaust pipe, 6. Combustion fan, 7. Gas inlet pipe, 8. Glass overflow port, 9. Flame spraying area. 10. Fly ash temporary storage bin, 11. Pelletizer, 12. Granulation bin, 13. Solvent storage bin, 14. Feeding system, 15. Buffer bin under-bin feeder, 16. Plasma melting furnace, 17. Flue gas cooler, 18. Induced draft fan, 19. Secondary fan, 20. Waste incinerator, 21. Domestic waste feeding system. DETAILED DESCRIPTION

[0017] The present invention is not limited to the following specific embodiments. A person skilled in the art can implement the present invention in various other specific embodiments according to the contents disclosed in the present invention, or any simple changes or modifications made to the design structure and ideas of the present invention fall within the protection scope of the present invention. It should be noted that the embodiments and features in the embodiments of the present invention can be combined with each other without conflict.

[0018] The present invention is further described in detail below in conjunction with embodiments:

[0019] A waste incineration fly ash plasma melting treatment system, see Figure 1 , including a fly ash temporary storage bin 10, a pneumatic conveying system, a pelletizing system (specifically including a pelletizer 11 and a pelletizing bin 12 for temporarily storing fly ash pellets), a feeding system 14, a buffer bin, a plasma melting furnace 16, a flue gas cooler 17, an induced draft fan 18 and a waste incinerator 20, which are sequentially and hermetically connected. The air outlet of the induced draft fan 18 is hermetically connected to the secondary air duct of the waste incinerator 20; it also includes a solvent warehouse 13, which is hermetically connected to the feeding system 14; the fly ash temporary storage bin 10 is used to receive the fly ash generated by the waste incinerator 20.

[0020] See Figure 2 The top of the plasma melting furnace 16 is staggered with plasma torches 3 and a first smoke exhaust pipe 4. The plasma melting furnace 16 is also provided with a glass overflow port 8 and a molten heavy metal discharge port 2. The glass overflow port 8 is located higher than the molten heavy metal discharge port 2, and the molten heavy metal discharge port 2 is located at the bottom of the plasma melting furnace 16. A gas inlet pipe 7 and a second smoke exhaust pipe 5 are also connected to the glass overflow port 8. One end of the gas inlet pipe 7 located at the glass overflow port 8 is used as a flame injection zone 9; the gas outlet ends of the first smoke exhaust pipe 4 and the second smoke exhaust pipe 5 are tightly connected to the gas inlet end of the induced draft fan 18, that is, the first smoke exhaust pipe 4 and the second smoke exhaust pipe 5 are tightly connected to the secondary air duct of the waste incinerator 20 through the induced draft fan 18.

[0021] See Figure 1 The waste incineration fly ash plasma melting treatment method is implemented by a waste incineration fly ash plasma melting treatment system, and the treatment method specifically includes the following steps:

[0022] 1) Collect fly ash generated by the waste incinerator 20, transport it to the pelletizing system through the pneumatic conveying system for pelletizing, and then send it to the feeding system 14;

[0023] 2) The solvent in the solvent storage tank 13 is sent to the feed system 14, and mixed with the fly ash pellets in the feed system 14, and then sent to the buffer tank; by adding the solvent, the SiO 2The content is greater than 25% (by weight) and the CaO content is greater than 45% (by weight) to ensure the stable operation of the glass body and reduce the thermal loss rate of the incineration residue;

[0024] 3) The buffer bin is provided with an under-bin feeder 1 for quantitative feeding. The mixture of fly ash pellets and co-solvent in the buffer bin is quantitatively fed into the plasma melting furnace 16 through the quantitative feeder. The organic matter in the fly ash pellets is gasified and cracked to form synthesis gas and discharged through the first exhaust pipe 4. The inorganic matter is melted into glass and overflows through the glass overflow port 8. The molten heavy metal in the glass is discharged through the molten heavy metal drain port 2. The flame spraying area 9 is in a burning state to remove the toxic and combustible gas in the flue gas synthesis gas at the glass overflow port 8 and strengthen the further combustion of the unburned matter in the glass, thereby reducing the generation of dioxins. Then the flue gas synthesis gas is discharged through the second exhaust pipe 5.

[0025] 4) Under the action of the induced draft fan 18, the flue gas synthesis gas discharged from the first smoke exhaust pipe 4 and the second smoke exhaust pipe 5 merge and enter the flue gas cooler 17. After being cooled, the flue gas enters the waste incinerator 20 through the secondary air duct of the waste incinerator 20.

[0026] In step 1), the pellet size is 10-15 mm, and the water content is less than 30% (by weight). In step 3), the temperature in the plasma melting furnace 16 is controlled at 1450-1600° C., which ensures that the time from the gasification and cracking of the fly ash pellets entering the plasma melting furnace 16 to the flue gas outlet is at least 2 seconds, and on the other hand, it can ensure that the fly ash pellets are completely burned.

[0027] In step 2), the solvents are limestone and quartz sand, and the amount of addition is such that SiO 2 The content is greater than 25% (by weight) and the CaO content is greater than 45% (by weight) to ensure the stable operation of the glass body while reducing the thermal loss rate of the incineration residue, and effectively reducing the viscosity of the glass body and improving fluidity.

[0028] This embodiment omits the setting of the secondary combustion chamber in the conventional technology, and directly quenches the generated flue gas synthesis gas, and then returns the secondary air duct to the waste incinerator 20. On the one hand, the waste incinerator 20 can be used to remove the combustible gas therein, enhance the mixing of the flue gas in the furnace and adjust the temperature field in the furnace.

[0029] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical solutions and concepts of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

[0030] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions 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 limiting the present invention. In addition, the terms "first", "second", and the like are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", and the like may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0031] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" 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 or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

Claims

1. A plasma melting disposal system for municipal solid waste incineration fly ash, characterized in that: it includes a fly ash temporary storage bin, a pneumatic conveying system, a pelletizing system, a feeding system, a buffer bin, a plasma melting furnace, a flue gas cooler, a induced draft fan and a municipal solid waste incinerator which are hermetically connected in sequence. The outlet of the induced draft fan is hermetically connected to the secondary air pipeline of the municipal solid waste incinerator. It also includes a flux bin which is hermetically connected to the feeding system. The fly ash temporary storage bin is used to receive the fly ash generated by the municipal solid waste incinerator; the plasma melting furnace is provided with a plasma torch (3) and a first exhaust pipe (4) whose tops are staggered with each other. The plasma melting furnace is also provided with a vitreous overflow port (8) and a molten heavy metal drain port (2). The position of the vitreous overflow port (8) is higher than the position of the molten heavy metal drain port (2), and the molten heavy metal drain port (2) is arranged at the bottom of the plasma melting furnace. A gas inlet pipe (7) and a second exhaust pipe (5) are also connected to the vitreous overflow port (8). One end of the gas inlet pipe (7) at the vitreous overflow port (8) serves as a flame injection area (9). The outlet ends of the first exhaust pipe (4) and the second exhaust pipe (5) are hermetically connected to the inlet end of the induced draft fan. During the process of plasma melting disposal of municipal solid waste incineration fly ash, the flame injection area (9) is in a combustion state, and the flue gas synthesis gas discharged from the first exhaust pipe (4) and the second exhaust pipe (5) converges under the action of the induced draft fan, and then enters the flue gas cooler for rapid cooling; the buffer bin is provided with a feeder (1) under the bin for quantitative feeding. The mixture of fly ash pellets and flux in the buffer bin is quantitatively fed into the plasma melting furnace through the feeder.

2. A method for plasma melting disposal of municipal solid waste incineration fly ash, characterized in that: it is implemented by the plasma melting disposal system for municipal solid waste incineration fly ash as described in claim 1. The disposal method specifically includes the following steps: 1) Collect the fly ash generated by the municipal solid waste incinerator, transport it to the pelletizing system through the pneumatic conveying system for pelletizing, and then send it to the feeding system; 2) Feed the cosolvent in the cosolvent tank into the feeding system, mix it with the fly ash pellets in the feeding system, and then feed it into the buffer tank; by adding the cosolvent, the SiO 2 content in the mixture > 25% (by weight), and the CaO content > 45% (by weight); 3) The buffer bin is provided with a feeder (1) under the bin for quantitative feeding. The mixture of fly ash pellets and flux in the buffer bin is quantitatively fed into the plasma melting furnace through the feeder. The organic matter in the fly ash pellets is gasified and cracked to form synthesis gas and discharged through the first exhaust pipe (4). The inorganic matter is melted into vitreous body and overflows through the vitreous overflow port (8). The molten heavy metal in the vitreous body is discharged through the molten heavy metal drain port (2). The flame injection area (9) is in a flame injection state, and then the flue gas synthesis gas is discharged through the second exhaust pipe (5); 4) Under the action of the induced draft fan, the flue gas synthesis gas discharged from the first exhaust pipe (4) and the second exhaust pipe (5) converges and then enters the flue gas cooler, and the flue gas enters the municipal solid waste incinerator through the secondary air pipeline of the municipal solid waste incinerator after being cooled.

3. According to the method for plasma melting disposal of municipal solid waste incineration fly ash as described in claim 2, characterized in that: in step 1), the pellet size is 10 - 15 mm, the water content is < 30% (by weight), and in step 3), the temperature in the plasma melting furnace is controlled at 1450 - 1600 °C.

4. The method for treating fly ash from waste incineration by plasma melting according to claim 2, characterized in that: In step (2), the cosolvent is limestone and quartz sand, and the addition amount is such that the SiO 2 content in the mixture > 25% (by weight), and the CaO content > 45% (by weight).

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