Resource utilization process and harmless treatment system for waste incineration fly ash

Abstract

The invention provides a waste incineration fly ash resource utilization process and a harmless treatment system. The process comprises the following steps: S1, washing with water to remove chlorine; s2, low-temperature thermal decomposition treatment; s3, high-temperature melting treatment; s4, carrying out sintering aid treatment while carrying out high-temperature melting treatment to prepare a glass body; s5, the glass body is used for replacing gravel materials to be used in building materials and pouring road surfaces, and the harmless treatment system adopts the technology to treat the fly ash generated by waste incineration. The harmless treatment system comprises a wedge-shaped filter press, a granulation module, a double-cylinder diaphragm used for conveying slurry to the granulation module, a plasma incinerator used for melting and sintering fly ash to prepare a sintered body, a feeding module used for conveying fly ash particles to the plasma incinerator, and a combustion assisting module used for blowing fuel gas into the plasma incinerator. According to the waste incineration fly ash harmless treatment system and method, harmless treatment of waste incineration fly ash is achieved, and the safety of fly ash recycling is improved.

Description

Technical Field

[0001] The invention relates to the field of environmental protection, in particular to a process for resource utilization of fly ash from garbage incineration, and also to a harmless treatment system using the process. Background Art

[0002] Domestic waste incineration power generation has gradually become the mainstream method of domestic waste disposal due to its advantages of significant reduction, less land resource occupation and energy conversion. However, waste incineration will produce secondary pollutants such as fly ash, which is enriched with fluorine, chlorine, organic pollutants such as benzopyrene, benzanthracene, dioxins, furans, and heavy metals such as lead, cadmium, and mercury in the incineration flue gas, which has become a difficult problem for its treatment and disposal. Fly ash is a hazardous waste with irreversible teratogenic, carcinogenic, and mutagenic properties, and has extremely strong neurotoxicity, which can cause serious damage to multiple organs of the human body. If fly ash is not properly handled, it will cause serious harm to the environment. Therefore, fly ash treatment is an issue that needs to be solved urgently. Summary of the invention

[0003] In view of the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide a waste incineration fly ash resource utilization process and a harmless treatment system to achieve harmless treatment of waste incineration fly ash and improve the safety of fly ash recycling.

[0004] A waste incineration fly ash resource utilization process, comprising the following processing steps:

[0005] S1 water washing to remove chlorine;

[0006] S2 low temperature thermal decomposition treatment;

[0007] S3 high temperature melting treatment;

[0008] S4 performs a sintering treatment while performing a high temperature melting treatment to prepare a glass body;

[0009] The glass body described in S5 is used as a substitute for sand and gravel in building materials and pouring pavement.

[0010] In one embodiment, waste incineration fly ash is washed with water to reduce the chlorine content to less than 1%.

[0011] In one embodiment, the operation process of the low-temperature thermal decomposition treatment is as follows: under anaerobic or anaerobic conditions, the washed fly ash is subjected to a thermal decomposition reaction at a temperature of 700 to 800° C., so that organic pollutants are removed from the fly ash matrix; the organic pollutants are polychlorinated biphenyls, polycyclic aromatic hydrocarbons and dioxins.

[0012] In one embodiment, the high temperature melting treatment method is specifically performed as follows:

[0013] S31: mixing fly ash with other silicon-aluminum components and flux to form a mixture A;

[0014] S32: transferring the mixed material A to a high temperature environment for melting treatment to form a mixed material B;

[0015] S33: The mixed material B is subjected to water rapid cooling treatment to obtain a sintered body.

[0016] In one embodiment, the temperature of the high temperature environment is greater than 1400° C., and the high temperature converts the fly ash into a glassy state; fuel gas is blown in for combustion-aiding treatment, and the temperature generated by the combustion-aiding treatment is the combustion-aiding temperature, which is lower than the melting temperature of the fly ash.

[0017] In one embodiment, S4 also includes pickling the prepared glass body and then grinding it; the operation process of the pickling treatment is as follows: pickling the glass body with low concentration hydrochloric acid to remove residual soluble salts in the glass body pores and activate the glass body.

[0018] A harmless treatment system, which uses the waste incineration fly ash resource utilization process to treat the fly ash generated by waste incineration, and the treatment system includes:

[0019] A filter press is used to make slurry from fly ash mixed with water;

[0020] a granulation module for converting the slurry into fly ash granules;

[0021] A plasma incinerator, which is used to melt and sinter fly ash to form a sintered body;

[0022] A combustion-supporting module, which is used to inject fuel gas into the plasma incinerator;

[0023] Flue gas treatment modules; and

[0024] Slag handling module.

[0025] In one embodiment, the processing system also includes a double-cylinder diaphragm pump for delivering the slurry to the granulation module, and a feeding module for delivering the fly ash particles to the plasma incinerator; the flue gas treatment module includes a boiler for recovering and utilizing the waste heat of the flue gas, a quenching tower for cooling the flue gas, and a bag dust collector for removing dust from the flue gas.

[0026] In one of the embodiments, the slag processing module includes a slag discharger for conveying the slag out of the plasma incinerator and a crusher for crushing the slag.

[0027] Furthermore, the slag processing module also includes a pickling module, which is used to pickle the slag.

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0029] 1. The resource utilization process of waste incineration fly ash of the present invention has the following advantages: A solidification and stabilization pretreatment system is established to realize the harmless treatment of waste incineration fly ash. The heavy metals in the glass body obtained by the process of this embodiment are non-leachable and can be used as a cement raw material additive, and the safety of reuse is high.

[0030] 2. The treatment system of the present invention has the following advantages: A high-temperature melting and sintering system of plasma melting + gas-assisted combustion is established to detoxify and reduce the volume of fly ash, realizing the harmless treatment of waste incineration fly ash. It overcomes the problems of local high temperature in the furnace, inability to cover a large area and long distance with temperature, and although the central temperature is very high, it is difficult to completely decompose and melt when the material passes through instantaneously. In addition, the fly ash product obtained by the treatment system of this embodiment has high application safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 The figure shows a flowchart of a resource utilization process of waste incineration fly ash provided in Embodiment 1 of the present invention.

[0032] Figure 2 As shown in the present invention Figure 1 a reaction mechanism diagram of high-temperature melting.

[0033] Figure 3 The figure shows a block diagram of a harmless treatment system provided in Embodiment 2 of the present invention.

[0034] Figure 4 The figure shows a block diagram of a harmless treatment system provided in Embodiment 3 of the present invention.

[0035] Description of Main Component Symbols

[0036] 1. Wedge filter press; 2. Granulation module; 3. Double-cylinder diaphragm pump; 4. Plasma incinerator; 5. Boiler; 6. Quenching tower; 7. Bag filter; 8. Slag discharger; 9. Crusher; 10. Pickling module.

[0037] The above description of main component symbols further elaborates the present invention in conjunction with the accompanying drawings and specific embodiments. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0038] The present invention will be described in detail below with reference to the accompanying drawings.

[0039] Embodiment 1

[0040] Fly ash is the aggregate of ash and dust collected during the incineration of municipal solid waste. It contains toxic substances such as heavy metals and dioxins and is classified as hazardous waste. The conventional disposal method is landfill, which poses a risk of secondary pollution. Figure 1 This embodiment provides a waste incineration fly ash resource utilization process, which includes the following steps:

[0041] S1. Water washing to remove chlorine. Since fly ash is rich in salt substances such as sodium chloride, it needs to be removed in advance to avoid environmental risks of subsequent resource utilization. Chloride ions are easily soluble in water and can be removed from the solution by washing with water. Therefore, in this embodiment, the waste incineration fly ash is washed with water (such as high-pressure water washing or spiral water washing) to deeply desalinate the fly ash to reduce the chlorine content to less than 1%. It should be noted that the fly ash becomes wet ash after water washing, and the moisture content is usually around 30%. The wet ash is easy to compact during the storage process. Therefore, the fly ash that has been compacted into large pieces needs to be broken up again during operation, which will not be elaborated here.

[0042] S2 Low-temperature thermal decomposition treatment. The operation process of the low-temperature thermal decomposition treatment is as follows: under anaerobic or anaerobic conditions, the washed fly ash is subjected to thermal decomposition reaction at a temperature of 800°C to remove organic pollutants from the fly ash matrix. The main components of the washed fly ash are silicon dioxide, calcium oxide, aluminum oxide, etc.

[0043] The organic pollutants are polychlorinated biphenyls, polycyclic aromatic hydrocarbons and dioxins. Taking dioxins as an example, the removal mechanism is as follows: dioxins undergo thermal decomposition reaction to generate carbon dioxide, hydrogen chloride, water and coke.

[0044] S3 high temperature melting treatment.

[0045] The high temperature melting treatment method is specifically operated as follows:

[0046] S31: fly ash is mixed with other silicon-aluminum components and flux to form a mixture A. The flux of this embodiment is described by taking red mud solid waste as an example, and the mixing ratio is 95% fly ash and 5% red mud. The addition of red mud solid waste facilitates the subsequent high-temperature melting and realizes the coordinated utilization of waste. The collected fly ash is mixed with water to obtain fly ash slurry, and a certain proportion of red mud solid waste is added to mix evenly, and then the slurry is centrifuged and dehydrated and filtered to obtain high-concentration slurry. The above process can remove salt substances in the fly ash.

[0047] S32 transfers the mixed material A to a high temperature environment for melting treatment to form a mixed material B. The temperature of the high temperature environment is greater than 1400° C., and the organic pollutants in the fly ash are decomposed based on the high temperature treatment.

[0048] S33 performs a water quenching treatment on the mixture B to obtain a sintered body. The mixture B is a high-temperature melt. The sintered body is a slag quenched after the high-temperature melt is rapidly cooled, is in the form of fine particles and has a dense structure.

[0049] Please refer to Figure 2 , by high-temperature melting, the fly ash is converted into a vitreous state, and heavy metals are stabilized in the dense structure of the sintered body. The dense particles in the sintered body surround the heavy metals and are difficult to leach, thereby achieving the purpose of reducing the leaching toxicity of heavy metals in fly ash. Moreover, after the fly ash is melted, only an increase in density can reduce the volume by more than 70%, increasing the bulk density accordingly. The same treatment space can accommodate more fly ash, improving the treatment capacity. This embodiment realizes the volume reduction, detoxification, and resource utilization of fly ash based on high-temperature melting treatment.

[0050] S4 While performing the high-temperature melting treatment, a co-firing treatment is carried out, and fuel gas is injected for oxygen-enriched co-firing treatment. The temperature generated by the co-firing treatment is the co-firing temperature, and the co-firing temperature is 1000°C lower than the fly ash melting temperature.

[0051] In this embodiment, based on the co-firing treatment for auxiliary heating, the material absorbs sufficient heat before reaching the melting point, so that the material can be instantaneously melted when passing through the melting point, overcoming the problems of difficult complete decomposition and melting of the material caused by local high temperature.

[0052] S5 The vitreous body is used to replace sand and gravel for building materials and pouring roads.

[0053] In summary, the resource utilization process of municipal solid waste incineration fly ash in this embodiment has the following advantages: a solidification and stabilization pretreatment system is established to realize the harmless treatment of municipal solid waste incineration fly ash. The fly ash product obtained by the process of this embodiment has high safety for reuse.

[0054] Embodiment 2

[0055] Please refer to Figure 3 , this embodiment provides a harmless treatment system, which uses the resource utilization process of municipal solid waste incineration fly ash as described in Embodiment 1 to treat the fly ash generated by municipal solid waste incineration. The treatment system includes a wedge-shaped filter press 1 for making the fly ash mixed with water into slurry, a granulation module 2 for making the slurry into fly ash particles, a double-cylinder diaphragm pump 3 for sending the slurry to the granulation module 2, a plasma incinerator 4 for melting and sintering the fly ash into a sintered body, a feeding module for sending the fly ash particles to the plasma incinerator 4, a co-firing module for injecting fuel gas into the plasma incinerator 4, a flue gas treatment module, and a slag treatment module.

[0056] In order to achieve an ideal incineration state, the present embodiment is provided with a granulation module 2 to process the slurry so that it becomes a granular material (such as a hollow sphere). The granulation module 2 adopts a spray drying granulator, and the feeding module adopts a screw feeder.

[0057] A plasma torch is provided in the middle of the furnace of the plasma incinerator 4, and the furnace body of the plasma incinerator 4 adopts chromium-zirconium-corundum bricks and hollow alumina ball bricks. Since the working temperature of the furnace is high and the high temperature scouring of the plasma torch will corrode the furnace body, the plasma incinerator 4 of this embodiment adopts chromium-zirconium-corundum bricks as the working layer, supplemented by hollow alumina ball bricks, to improve the high temperature resistance of the furnace body and ensure the normal operation of the plasma incinerator 4. In this embodiment, the fly ash particles are mixed with other silicon-aluminum components and flux, and then processed by the granulation module 2 to become hollow particles, and then put into the plasma incinerator by the feeding module, and high-temperature melting and sintering treatment is achieved from top to bottom by the plasma torch to form a sintered body with a dense structure.

[0058] The plasma incinerator 4 of this embodiment uses a high temperature of not less than 1400°C to convert fly ash into a glassy state, stabilizes heavy metals in the dense structure of the sintered body, and the dense particles in the sintered body surround the heavy metals to reduce the toxicity of heavy metal leaching from the fly ash, meeting the toxicity standard requirements for hazardous waste leaching, and the density of the fly ash after melting can be reduced by more than 70%, so that the stacking density is correspondingly increased, and the same processing space can accommodate more fly ash, thereby increasing the processing capacity. This embodiment achieves volume reduction, toxicity reduction, and resource utilization of fly ash based on high-temperature melting and sintering.

[0059] The plasma torch causes local high temperature in the furnace, and the temperature cannot cover a large area and a long distance. Although the center temperature is very high, it is difficult to completely decompose and melt the material when it passes through instantly. Therefore, the present embodiment arranges a combustion-aiding module to blow fuel gas into the furnace for auxiliary heating, so that the temperature of the entire furnace reaches the fly ash melting temperature, and maintains the temperature in the furnace to ensure that the material absorbs enough heat before reaching the plasma torch, so that the material can be instantly melted when passing through the plasma torch.

[0060] Since flue gas can pollute the atmospheric environment, the flue gas generated when the plasma incinerator 4 burns fly ash needs to be purified of harmful substances by the flue gas treatment module before being discharged. The flue gas treatment module includes a boiler 5 for recycling the waste heat of the flue gas, a quenching tower 6 for cooling the flue gas, and a bag filter 7 for removing dust from the flue gas. The flue gas treatment module of this embodiment has the following processing process: the induced draft fan extracts the flue gas in the plasma incinerator 4, and the waste heat of the flue gas is recovered to supply the boiler 5. During the transmission of the flue gas, it is successively subjected to rapid cooling, dust removal, deacidification and denitrification treatment, and then discharged into the atmosphere along the chimney.

[0061] The glass slag falls into the water pool at the bottom of the furnace and breaks when it is cooled. The glass slag is removed from the water pool by a slag removal device. The slag processing module includes a slag discharger 8 for sending the slag out of the plasma incinerator 4 and a crusher 9 for crushing the slag. The slag discharger 8 outputs the slag in a directional manner. After the slag is crushed, it is sent out for storage or further processed, such as making cement blocks, for reuse.

[0062] Example 3

[0063] See also Figure 4 , this embodiment provides a harmless treatment system, which differs from Embodiment 2 in that: the slag treatment module also includes a pickling module 10, which is used to pickle the slag. Before entering the crusher 9, the slag (i.e., the glass) is first pickled with low-concentration hydrochloric acid to remove the residual soluble salts in the glass pores and activate the glass. In this embodiment, the soluble salts in the fly ash slag are removed based on the pickling treatment, so as to avoid the electrochemical effect of salts forming ions between cement particles when the fly ash is made into mortar, making it difficult for the ions to penetrate and react chemically with cement, thereby affecting the strength of the obtained cement block, providing favorable conditions for subsequent utilization. The cement block made of mortar treated by the pickling module 10 has higher compressive strength and higher application safety than the cement block directly prepared by skipping this step.

[0064] In summary, the processing system of this embodiment has the following advantages: a high-temperature melting and sintering system of plasma melting + gas-assisted combustion is established to detoxify and reduce the volume of fly ash, thereby achieving harmless treatment of fly ash from waste incineration, overcoming the problem of local high temperature in the furnace and the inability to cover a large area and long distance with temperature. Although the center temperature is very high, it is difficult to completely decompose and melt the material when it passes through instantly. In addition, the fly ash product obtained by the processing system of this embodiment has high safety in application.

[0065] The naming of each component involved is based on its function described in the specification and is not limited to the specific terms used in the present invention. Those skilled in the art may also choose other terms to describe the names of the components of the present invention.

Claims

1. A process for resource utilization of fly ash from waste incineration, characterized in that: It includes the following processing steps: S1 Wash to remove chlorine; S2 Low-temperature thermal decomposition treatment; S3 High-temperature melting treatment; S4 While performing the high-temperature melting treatment, perform a sintering aid treatment to prepare a vitreous body; S5 Use the vitreous body to replace sand and gravel for building materials and poured roads.

2. The process for recycling waste incineration fly ash according to claim 1, characterized in that: Wash the fly ash from waste incineration to reduce the chlorine content to less than 1%.

3. The process for recycling waste incineration fly ash according to claim 2, characterized in that: The operation process of the low-temperature thermal decomposition treatment is as follows: Under anoxic or anaerobic conditions, the washed fly ash undergoes a thermal decomposition reaction at a temperature of 700-800°C, so that organic pollutants are removed from the fly ash matrix; The organic pollutants are polychlorinated biphenyls, polycyclic aromatic hydrocarbons, and dioxins.

4. The process for recycling waste incineration fly ash according to claim 1, characterized in that: The method of the high-temperature melting treatment is specifically operated as follows: S31 Mix the fly ash with other aluminosilicate components and a flux to form mixture A; S32 Transfer mixture A to a high-temperature environment for melting treatment to form mixture B; S33 Perform a water quenching treatment on mixture B to obtain a sintered body.

5. The process for recycling waste incineration fly ash according to claim 4, characterized in that: The temperature of the high-temperature environment > 1400°C, and the high temperature converts the fly ash into a glassy state; Inject fuel gas for sintering aid treatment, and the temperature generated by the sintering aid treatment is the sintering aid temperature, and the sintering aid temperature is lower than the fly ash melting temperature.

6. The process for recycling waste incineration fly ash according to claim 1, characterized in that: S4 also includes pickling the prepared vitreous body and then grinding it; The operation process of the pickling treatment is as follows: Pickle the vitreous body with low-concentration hydrochloric acid to remove residual soluble salts in the vitreous body pores and activate the vitreous body.

7. A harmless treatment system, which uses the waste incineration fly ash resource utilization process as described in any one of claims 1 to 6 to treat the fly ash generated by waste incineration, characterized in that: The treatment system includes: A wedge-shaped filter press (1) for making the fly ash mixed with water into a slurry; A granulation module (2) for making the slurry into fly ash particles; A plasma incinerator (4) for melting and sintering fly ash to form a sintered body; A sintering aid module for injecting fuel gas into the plasma incinerator (4); A flue gas treatment module; and A slag treatment module.

8. The harmless treatment system according to claim 7, characterized in that: The treatment system also includes a double-diaphragm pump (3) for sending the slurry to the granulation module (2), and a feeding module for sending the fly ash particles to the plasma incinerator (4); The flue gas treatment module includes a boiler (5) for recovering and utilizing the waste heat of the flue gas, a quench tower (6) for cooling and reducing the temperature of the flue gas, and a bag filter (7) for dust removal of the flue gas.

9. The harmless treatment system according to claim 7, characterized in that: The slag treatment module includes a slag discharge machine (8) for discharging the slag from the plasma incinerator (4) and a crusher (9) for crushing the slag.

10. The harmless treatment system according to claim 9, characterized in that: The slag treatment module also includes a pickling module (10) for pickling the slag.

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