Low-temperature pyrolysis equipment for waste incineration fly ash

Abstract

The utility model relates to the field of waste incineration fly ash disposal, and discloses waste incineration fly ash low-temperature pyrolysis equipment. The equipment is composed of a drying and pyrolyzing furnace and a cooling spiral, the drying and pyrolyzing furnace is divided into a drying section and a pyrolyzing section, and the two sections are connected through a specific connector. The drying section is used for drying the fly ash, the pyrolysis section is used for performing low-temperature pyrolysis on the fly ash in an anaerobic environment, nitrogen can be injected into the pyrolysis section to maintain anaerobic, and a stirring shaft adopts a gas sealing shaft seal with a water cooling device to prevent oxygen from permeating. The cooling spiral is of a jacket type water cooling structure and can rapidly cool pyrolyzed fly ash. A heating assembly of the equipment adopts a U-shaped electric heating pipe and is matched with a temperature sensor, so that the temperature can be accurately controlled; the double-shaft stirring and conveying system enables materials to be heated uniformly, and the pyrolysis efficiency is improved; each section is further provided with an access hole for facilitating maintenance, and a star-shaped discharge valve for cooling a spiral discharge hole controls discharge of materials. The equipment is close to zero emission, and fly ash treatment products can be recycled.

Description

Technical Field

[0001] This utility model relates to the field of waste incineration fly ash disposal, specifically to a low-temperature pyrolysis device for waste incineration fly ash. Background Technology

[0002] During waste incineration, chlorinated organic compounds are oxidized and decomposed into smaller chlorinated organic molecules, which can then be resynthesized into dioxins during flue gas cooling. Dioxins, as chlorinated polynuclear aromatic compounds, are extremely toxic to living organisms. Waste incineration plants commonly use a "secondary combustion chamber + quench tower + activated carbon adsorption" process to control pollution and achieve compliant emissions of incineration flue gas. However, residual dioxins after flue gas treatment accumulate in the fly ash from waste incineration. According to the "Technical Specification for Pollution Control of Fly Ash from Municipal Solid Waste Incineration (Trial)" (HJ 1134-2020), the dioxin content after fly ash detoxification must not exceed 50 ng-TEQ / kg.

[0003] Currently, while traditional high-temperature treatment technologies can completely decompose dioxins, their high energy consumption limits their widespread application. Research has found that dioxins can be decomposed under anaerobic conditions at 300-500℃, leading to the development of low-temperature fly ash pyrolysis technology. However, existing pyrolysis furnace equipment has some structural design flaws. The shaft seal structure of the existing pyrolysis furnace stirring and conveying system cannot effectively isolate outside air, making it difficult to control the oxygen content during pyrolysis and affecting dioxin decomposition efficiency. Furthermore, the entry of outside air into the pyrolysis furnace may trigger oxidation reactions of some components in the fly ash, interfering with the pyrolysis process and potentially producing other harmful side reactions. Moreover, the structural design for the connection and collaborative operation between various functional modules is inadequate, making the material conveying process prone to blockages and jams, affecting overall processing efficiency. Utility Model Content

[0004] To address the above problems, the purpose of this utility model is to provide a low-temperature pyrolysis device for waste incineration fly ash, which achieves efficient detoxification of dioxins in fly ash through process optimization and equipment manufacturing intensification.

[0005] A low-temperature pyrolysis device for waste incineration fly ash includes:

[0006] A drying pyrolysis furnace and a cooling spiral; the drying pyrolysis furnace is divided into a drying section and a pyrolysis section, wherein:

[0007] The drying section includes a drying furnace body, a first heating chamber disposed at the lower part of the drying section, a first stirring and conveying chamber disposed at the upper part of the drying section, a drying inlet, a drying outlet, and a drying flue gas outlet; the first heating chamber includes a heating component and a temperature measuring component; the first stirring and conveying chamber includes a dual-shaft stirring and conveying system;

[0008] The pyrolysis section includes a pyrolysis furnace body, a second heating chamber located at the lower part of the pyrolysis section, a second stirring and conveying chamber located at the upper part of the pyrolysis section, a pyrolysis feed inlet, a pyrolysis discharge outlet, a nitrogen inlet, and a pyrolysis flue gas outlet; the second heating chamber includes a heating component and a temperature measuring component; the second stirring and conveying chamber includes a dual-shaft stirring and conveying system;

[0009] The drying section and the pyrolysis section are connected through the drying outlet and the pyrolysis inlet;

[0010] The cooling spiral includes a cooling spiral body, a cooling water inlet, a cooling water outlet, a cooling feed inlet, and a cooling discharge outlet; preferably, the cooling spiral is a jacketed water-cooled spiral conveyor.

[0011] The pyrolysis outlet of the drying pyrolysis furnace is connected to the cooling inlet of the cooling screw via a discharge screw conveyor.

[0012] Furthermore, the heating component is a U-shaped electric heating tube, and a temperature measuring component is provided at the front end of the heating component. The temperature measuring component is a temperature sensor, and at least one heating component is provided in both the drying section and the pyrolysis section.

[0013] Furthermore, the dual-shaft stirring and conveying system includes two sets of symmetrically arranged stirring shafts, each of which is equipped with detachable stirring blades and is synchronously driven by gear transmission, with a rotation speed of 1-5 rpm and adjustable frequency.

[0014] Furthermore, the stirring shaft is sealed with a gas-sealed shaft seal equipped with a water-cooling device to prevent oxygen from seeping in during pyrolysis.

[0015] Furthermore, the temperature measuring assembly includes a patch-type temperature measuring element, which is fixed to the inner wall of the heating chamber of the drying section and the pyrolysis section, and is provided with a protective box structure on the outside.

[0016] Furthermore, multiple inspection ports are symmetrically provided on the top side of the stirring and conveying chamber of the drying section and the pyrolysis section for the maintenance of the stirring blades.

[0017] Furthermore, the outlet of the cooling spiral is equipped with a star-shaped discharge valve to control the discharge of cooled material.

[0018] Furthermore, the furnace bodies of the drying section and the pyrolysis section are each equipped with independent flue gas outlets. The drying flue gas outlet is connected to the waste gas treatment system, and the pyrolysis furnace flue gas outlet is connected to the harmless treatment device after dioxin decomposition.

[0019] Furthermore, the nitrogen inlet of the pyrolysis section is used to inject nitrogen into the furnace to maintain an oxygen-free environment during the pyrolysis process.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The pyrolysis section of this equipment can be injected with nitrogen to maintain an oxygen-free environment, and the special seal of the stirring shaft prevents oxygen from seeping in. The dioxin treatment efficiency reaches 99%, and the dioxin concentration in fly ash is less than 30 ng-TEQ / kg, which is better than the environmental protection standard. This solves the problem of the difficulty in controlling the oxygen content in existing pyrolysis furnaces, which affects the decomposition of dioxins.

[0022] The dual-shaft mixing and conveying system consists of two symmetrically arranged mixing shafts, synchronously driven by gear transmission. The mixing blades are detachable, ensuring thorough mixing, heating, and conveying of materials. This prevents uneven heating and incomplete pyrolysis, thus improving pyrolysis efficiency. Multiple inspection ports are symmetrically located on the top side of the mixing and conveying chambers in both the drying and pyrolysis sections, facilitating blade maintenance, reducing equipment downtime, and ensuring stable operation. A star-shaped discharge valve at the cooling spiral outlet controls the discharge of cooled materials, making the entire process smoother and improving overall processing efficiency.

[0023] The U-shaped electric heating tube, together with the front-end temperature sensor, and the patch-type temperature sensing element with a protective box, are fixed on the inner wall of the heating chamber. The temperature of the drying section and the pyrolysis section can be adjusted as needed to ensure that the pyrolysis is within the optimal temperature range and to avoid abnormal reactions of fly ash.

[0024] The fly ash processing products are rich in minerals such as calcium, silicon, and aluminum, making them high-quality building material additives. Building materials produced using this equipment meet environmental and technical standards, achieving resource reuse. The low-temperature pyrolysis process in this equipment consumes only 15% of the energy of high-temperature processes, with minimal emissions, approaching zero. Compared to traditional high-temperature technologies, this significantly reduces energy consumption and pollution. Attached Figure Description

[0025] Figure 1 This is a front view of a fly ash low-temperature pyrolysis device according to a certain embodiment of the present invention;

[0026] Figure 2 This is a rear view of a fly ash low-temperature pyrolysis device according to a certain embodiment of the present invention;

[0027] Figure 3 This is a schematic diagram of the dual-shaft stirring and conveying system and temperature measuring component of a fly ash low-temperature pyrolysis device according to a certain embodiment of the present invention.

[0028] The numbers in the diagram represent: 1. Drying furnace flue gas outlet; 2. Drying furnace body; 3. Heating component; 4. Temperature measuring component; 5. Inspection port; 6. Drying feed inlet; 7. Dual-shaft drive system; 8. Drying discharge outlet; 9. Nitrogen inlet; 10. Pyrolysis furnace feed inlet; 11. Pyrolysis furnace body; 12. Pyrolysis furnace flue gas outlet; 13. Discharge screw conveyor; 14. Cooling screw body; 15. Cooling feed inlet; 16. Cooling discharge outlet; 17. Cooling water inlet; 18. Cooling water outlet. Detailed Implementation

[0029] To enable those skilled in the art to better understand the present invention, the invention method will be further described in detail below with reference to the following specific embodiments and accompanying drawings, but this does not limit the invention to the scope of the embodiments.

[0030] Please see Figures 1-2 The drying pyrolysis furnace is divided into a drying section and a pyrolysis section, and the two sections are connected to the pyrolysis section inlet 10 through the drying section outlet 8.

[0031] Drying Section: The drying furnace body 2 consists of a lower heating chamber and an upper stirring and conveying chamber. Four sets of U-shaped electric heating tubes 3 are installed in the lower heating chamber for drying and heating fly ash; a temperature sensor is configured at the front end of the heating components to monitor the heating temperature in real time.

[0032] The upper mixing and conveying chamber is equipped with a dual-shaft mixing and conveying system 7, consisting of two sets of symmetrical mixing shafts. Each shaft is equipped with 12 sets of detachable mixing blades, which are synchronously driven by gear transmission. The rotation speed is 1-5 rpm and is frequency-adjustable. The top of the drying section is equipped with a drying inlet 6 for fly ash input, and the side wall is equipped with a drying flue gas outlet 1 connected to the waste gas treatment system.

[0033] Pyrolysis Section: The pyrolysis furnace body 11 has a similar structure to the drying section. Its lower heating chamber is also equipped with four sets of U-shaped electric heating tubes 3, and the heating temperature is precisely controlled by patch-type temperature sensing elements 4. A nitrogen inlet 9 is located on the side wall of the pyrolysis section and is used to inject nitrogen to maintain an oxygen-free environment. The pyrolysis flue gas outlet 12 is connected to a dioxin harmless treatment device. The pyrolysis section discharge is connected to the cooling inlet 15 of the cooling screw conveyor 13.

[0034] Eight inspection ports 5 are symmetrically arranged on the top side of the upper cavity of the drying section and the pyrolysis section to facilitate the disassembly and maintenance of the stirring blades.

[0035] Please see Figure 1 and 3The cooling spiral is a jacketed water-cooled spiral conveyor, comprising the following parts: Cooling spiral body 14: Adopting a jacketed cylindrical structure, cooling water is introduced into the jacket and circulated through the cooling water inlet 17 and cooling water outlet 18 for cooling. Spiral shaft cooling system: The spiral shaft is cooled by a shaft cooling device with a rotary joint to prevent overheating; the jacketed cylindrical body and shaft cooling work together to ensure rapid cooling of fly ash during conveying. Rotary star discharge valve: Located at the cooling outlet 16, used to control the discharge rate of cooled material and prevent fly ash accumulation.

[0036] The fly ash treatment process is as follows:

[0037] Fly ash enters the drying section through the drying inlet 6, and is uniformly heated and dried under the stirring of the dual-shaft stirring and conveying system 7. The dried flue gas is discharged for treatment through the dried flue gas outlet 1.

[0038] The dried fly ash enters the pyrolysis section through the drying outlet 8, where it undergoes low-temperature pyrolysis in an oxygen-free environment, and dioxins decompose at 300-500℃.

[0039] After pyrolysis, the fly ash is conveyed to the cooling screw conveyor via a discharge screw conveyor. Cooling water circulates in the jacket and screw shaft to reduce the fly ash temperature to a safe range.

[0040] The cooled fly ash is discharged through the star-shaped discharge valve 16 and can be directly used as a building material raw material, realizing resource utilization.

[0041] It should be noted that the above embodiments are only used to illustrate the technical solution of this utility model, and not to limit it. Those skilled in the art can make adjustments or modifications to the specific implementation methods without departing from the principle of this utility model, and such adjustments or modifications should all be covered within the protection scope of this utility model.

Claims

1. A waste incineration fly ash low-temperature pyrolysis apparatus, characterized by, include: A drying pyrolysis furnace and a cooling spiral; the drying pyrolysis furnace is divided into a drying section and a pyrolysis section, wherein: The drying section includes a drying furnace body (2), a first heating chamber located at the lower part of the drying section, a first stirring and conveying chamber located at the upper part of the drying section, a drying inlet (6), a drying outlet (8), and a drying flue gas outlet (1); the first heating chamber includes a heating component (3) and a temperature measuring component (4); the first stirring and conveying chamber includes a dual-shaft stirring and conveying system (7); The pyrolysis section includes a pyrolysis furnace body (11), a second heating chamber located at the lower part of the pyrolysis section, a second stirring and conveying chamber located at the upper part of the pyrolysis section, a pyrolysis feed inlet (10), a discharge screw conveyor (13), a nitrogen inlet (9), and a pyrolysis furnace flue gas outlet (12); the second heating chamber includes a heating component (3) and a temperature measuring component (4); the second stirring and conveying chamber includes a dual-shaft stirring and conveying system (7); The drying section and the pyrolysis section are connected to the pyrolysis inlet (10) through the drying outlet (8); The cooling spiral includes a cooling spiral body (14), a cooling water inlet (17), a cooling water outlet (18), a cooling feed inlet (15), and a cooling discharge outlet (16); The pyrolysis outlet of the drying pyrolysis furnace is connected to the cooling inlet (15) of the cooling screw via a discharge screw conveyor (13).

2. The waste incineration fly ash low temperature pyrolysis apparatus according to claim 1, characterized by, The heating component (3) is a U-shaped electric heating tube. The front end of the heating component (3) is provided with a temperature measuring component (4), which is a temperature sensor. At least 4 sets of heating components (3) are provided in the drying section and the pyrolysis section respectively.

3. The waste incineration fly ash low temperature pyrolysis apparatus according to claim 1, characterized by, The dual-shaft mixing and conveying system (7) includes two sets of symmetrically arranged mixing shafts. Each mixing shaft is equipped with a detachable mixing blade and is synchronously driven by gear transmission. The rotation speed is 1-5 rpm and the frequency is adjustable.

4. The waste incineration fly ash low temperature pyrolysis apparatus according to claim 3, characterized by, The stirring shaft is sealed with a gas-sealed shaft seal equipped with a water-cooling device to prevent oxygen from seeping in during pyrolysis.

5. The waste incineration fly ash low temperature pyrolysis apparatus according to claim 1, characterized by, The temperature measuring component (4) includes a patch-type temperature measuring element, which is fixed to the inner wall of the heating chamber of the drying section and the pyrolysis section, and is provided with a protective box structure on the outside.

6. The waste incineration fly ash low temperature pyrolysis apparatus according to claim 1, characterized by, Multiple inspection ports (5) are symmetrically arranged on the top side of the mixing and conveying chamber of the drying section and the pyrolysis section for the maintenance of the mixing blades.

7. The waste incineration fly ash low temperature pyrolysis apparatus according to claim 1, characterized by, The outlet (16) of the cooling spiral is equipped with a star-shaped discharge valve to control the discharge of cooled material.

8. The waste incinerated fly ash low temperature pyrolysis apparatus as claimed in claim 1, wherein, The furnace bodies of the drying section and the pyrolysis section are respectively provided with independent flue gas outlets. The drying flue gas outlet (1) is connected to the waste gas treatment system, and the pyrolysis furnace flue gas outlet (12) is connected to the harmless treatment device after dioxin decomposition.

9. The waste incineration fly ash low temperature pyrolysis apparatus according to claim 1, characterized by, The nitrogen inlet (9) of the pyrolysis section is used to inject nitrogen into the furnace to maintain an oxygen-free environment during the pyrolysis process.

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