Domestic waste incineration fly ash detoxification and quality improvement treatment system
A multi-stage fly ash treatment system stabilizes and removes contaminants, addressing high costs and secondary pollution in existing systems by using pre-solution tanks, water washing, and thermal decomposition to produce low-carbon cementitious materials.
Patent Information
- Application Number
- CN202422142574.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-02
- Publication Date
- 2025-07-15
- Estimated Expiration
- 2034-09-02
AI Technical Summary
In the prior art, when dealing with fly ash incineration in domestic waste, it is difficult to effectively remove dioxins, heavy metals and soluble salts, resulting in high disposal costs and environmental protection risks in the resource utilization process.
The combination process of pre-soluble slurry tank, multi-stage water washing device, low-temperature thermal decomposition equipment and solid-liquid separation equipment is adopted to remove harmful substances in fly ash through oxidation, carbonization, water washing and low-temperature thermal decomposition, and the unstable components are converted into stable components, combining sodium sulfate agents and wastewater zero-discharge device to achieve resource utilization.
The effective removal of dioxins, heavy metals and soluble salts in fly ash is achieved, which reduces the cost of disposal, and improves the stability and economic value of resource utilization. The generated low-carbon gelled materials have high activity and stability.
Smart Images
Figure CN223097606U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of harmless disposal and resource utilization of fly ash from domestic waste incineration, in particular to a detoxification and quality improvement treatment system for fly ash from domestic waste incineration. Background Art
[0002] After the incineration of domestic waste, 3% to 5% of fly ash will be produced. The annual amount of fly ash produced by waste incineration is large, and the heavy metals, dioxins, soluble salts and other substances in it have a great impact on the ecological environment. As a flue gas reaction product, the unstable components in it have a great impact on the strength, water absorption, expansion and other properties in the subsequent resource utilization process of building materials.
[0003] At present, the detoxification and quality improvement treatment system for fly ash from the incineration of domestic waste generally focuses on destroying or removing toxic and harmful substances in fly ash, and only removes dioxins and soluble chloride salts in fly ash. Little attention is paid to the stability of the main components and the treatment cost of water treatment, which leads to high costs in the fly ash disposal process. In addition, the components in fly ash are relatively complex and contain a variety of chloride salts, sulfates, sulfites, carbonates and strong alkaline substances. The instability of sulfites and strong alkaline substances can easily lead to slow setting and expansion of building materials during their utilization as building materials, and will repeatedly release polluted gases, causing secondary hazards. Therefore, it is of environmental and economic significance to develop a process for the harmless disposal and resource utilization of fly ash that removes pollutants, stabilizes components, and has low costs. Utility Model Content
[0004] In order to solve at least one of the technical problems mentioned in the background technology, the purpose of the utility model is to provide a detoxification and quality improvement treatment system for fly ash from the incineration of domestic waste, which can comprehensively achieve the advantages of effective removal of pollutants in fly ash from the incineration of domestic waste, stabilization of components, and low removal cost.
[0005] In order to achieve the above purpose, the utility model provides the following technical solutions:
[0006] A system for detoxifying and improving fly ash from incineration of domestic waste, comprising:
[0007] A pre-dissolving slurry tank, used to dissolve the fly ash into slurry, wherein the pre-dissolving slurry tank is equipped with an oxygen and carbon dioxide supplement device;
[0008] A water washing device, the feed inlet of which is connected to the discharge outlet of the pre-dissolving slurry tank;
[0009] Sodium sulfate dosing pump, used to continuously add sodium sulfate agent into the water washing device;
[0010] A solid-liquid separation device, whose feed inlet is communicated with the discharge outlet of a water washing device, whose liquid material discharge outlet is communicated with the pipe fittings of a heavy metal removal device, and whose solid discharge outlet is communicated with a low-temperature thermal decomposition device;
[0011] A zero wastewater discharge device, whose feed inlet is communicated with the wastewater discharge outlet of a heavy metal removal device through pipe fittings;
[0012] A heat treatment furnace, whose feed inlet is communicated with the discharge outlet of a low-temperature thermal decomposition device.
[0013] Preferably, the water washing device includes a primary water washing tank, a secondary water washing tank and a tertiary water washing tank, and the solid-liquid separation device includes a primary solid-liquid separation device, a secondary solid-liquid separation device and a tertiary solid-liquid separation device;
[0014] The feed inlet of the primary water washing tank is communicated with the discharge outlet of a pre-dissolving slurry tank, and its discharge outlet is communicated with the feed inlet of the primary solid-liquid separation device;
[0015] The feed inlet of the secondary water washing tank is communicated with the solid discharge outlet of the primary solid-liquid separation device, and its discharge outlet is communicated with the feed inlet of the secondary solid-liquid separation device;
[0016] The feed inlet of the tertiary water washing tank is communicated with the solid discharge outlet of the secondary solid-liquid separation device, and its discharge outlet is communicated with the feed inlet of the tertiary solid-liquid separation device. The solid discharge outlet of the tertiary solid-liquid separation device is communicated with the feed inlet of the low-temperature thermal decomposition device.
[0017] Preferably, the discharge outlet of the zero wastewater discharge device is communicated with the water inlet of the tertiary water washing tank.
[0018] Preferably, the liquid discharge outlet of the tertiary solid-liquid separation device is communicated with the water inlet of the pre-dissolving slurry tank.
[0019] Preferably, a stirrer is installed in the pre-dissolving slurry tank.
[0020] Preferably, when the low-temperature thermal decomposition device works, the thermal decomposition temperature is less than 500 °C, the oxygen content in the device is less than 2%, and the low-temperature thermal decomposition time is 60 min to 120 min.
[0021] Compared with the prior art, the beneficial effects of the present utility model are:
[0022] The utility model removes dioxins, heavy metals, and soluble chlorides in waste incineration fly ash, and realizes the high-quality utilization of the extraction of heavy metals and soluble chlorides; by stabilizing unstable compounds in the fly ash, the quality and environmental protection risks of the disposal products in the process of resource utilization are avoided; by initially adding calcium removal agents during the water washing process, while changing the cost of the fly ash treatment products, the disposal cost is reduced, and the solidification of carbon dioxide can be achieved; the low-carbon cementitious material produced by the disposal and treatment of the utility model has improved activity and stability, and can effectively realize greater economic value. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] Figure 1 is the overall treatment flow chart of fly ash for the utility model;
[0024] In the figure: 1. Pre-melting slurry tank; 21. First-stage water washing tank; 22. Second-stage water washing tank; 23. Third-stage water washing tank; 31. First-stage solid-liquid separation device; 32. Second-stage solid-liquid separation device; 33. Third-stage solid-liquid separation device; 4. Low-temperature thermal decomposition equipment; 5. Heat treatment furnace; 6. Heavy metal removal equipment; 7. Wastewater zero-discharge device; 8. Oxygen and carbon dioxide supplementation device; 9. Sodium sulfate dosing pump; 10. Stirrer. DETAILED DESCRIPTION OF THE EMBODIMENTS
[0025] The technical solutions in the embodiments of the present utility model will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts shall fall within the protection scope of the present utility model.
[0026] Please refer to Figure 1, this embodiment provides a system for detoxifying and upgrading municipal solid waste incineration fly ash, including a pre-melting slurry tank 1 for melting fly ash into slurry, and an oxygen and carbon dioxide supplementation device 8 is installed on the pre-melting slurry tank 1 to oxidize the unoxidized substances and carbonize the carbonizable substances in the fly ash slurry to obtain the oxidized and carbonized slurry; the feed port of the water washing device is connected to the discharge port of the pre-melting slurry tank 1, and a sodium sulfate dosing pump 9 is installed on the water washing device to continuously inject sodium sulfate reagent into the water washing device; the feed port of the solid-liquid separation equipment is connected to the discharge port of the water washing device, and the liquid discharge port of the solid-liquid separation equipment is connected to the heavy metal removal equipment 6 through pipes, and the heavy metal removal equipment 6 is used to precipitate heavy metals in the water washing filtrate; a low-temperature thermal decomposition equipment 4 is connected to the solid discharge port of the solid-liquid separation equipment; the feed port of the zero liquid discharge device 7 is connected to the waste water discharge port of the heavy metal removal equipment 6 through pipes, and the zero liquid discharge device 7 is used to evaporate and crystallize the waste water, and separate substances such as sodium chloride and potassium chloride to realize resource utilization. The feed port of the heat treatment furnace 5 is connected to the discharge port of the low-temperature thermal decomposition equipment 4.
[0027] Specifically, the water washing device includes a primary water washing tank 21, a secondary water washing tank 22 and a tertiary water washing tank 23, and the solid-liquid separation equipment includes a primary solid-liquid separation device 31, a secondary solid-liquid separation device 32 and a tertiary solid-liquid separation device 33; the feed port of the primary water washing tank 21 is connected to the discharge port of the pre-melting slurry tank 1, and its discharge port is connected to the feed port of the primary solid-liquid separation device 31; the sodium sulfate dosing pump 9 is used to add medicine to the primary water washing tank 21; the feed port of the secondary water washing tank 22 is connected to the solid discharge port of the primary solid-liquid separation device 31, and its discharge port is connected to the feed port of the secondary solid-liquid separation device 32; the feed port of the tertiary water washing tank 23 is connected to the solid discharge port of the secondary solid-liquid separation device 32, and its discharge port is connected to the feed port of the tertiary solid-liquid separation device 33, and the solid discharge port of the tertiary solid-liquid separation device 33 is connected to the feed port of the low-temperature thermal decomposition equipment 4.
[0028] Further, the discharge port of the zero liquid discharge device 7 is connected to the water inlet of the tertiary water washing tank 23.
[0029] Further, the liquid discharge port of the tertiary solid-liquid separation device 33 is connected to the water inlet of the pre-melting slurry tank 1, and using the water washing filtrate of the subsequent process as the slurry-making water further saves the use of water resources.
[0030] Further, a stirrer 10 is installed in the pre-melting slurry tank 1, which can quickly and evenly mix the fly ash and the slurry-making water, and improve the dissolution efficiency of the fly ash.
[0031] Specifically, when the low-temperature thermal decomposition equipment 4 works, the thermal decomposition temperature is less than 500 °C, the oxygen content in the equipment is less than 2%, and the low-temperature thermal decomposition time is 60 min to 120 min.
[0032] The following is an introduction to the specific treatment process of municipal solid waste incineration fly ash:
[0033] 1. Import the municipal solid waste incineration fly ash into the pre-dissolution slurry tank 1 to form a fly ash slurry with the internal water washing filtrate. Then, introduce oxygen and carbon dioxide gases into the fly ash slurry at a certain ratio to oxidize the unoxidized substances and carbonize the carbonizable substances in the fly ash slurry, obtaining the oxidized and carbonized slurry. During the processes of oxidation and carbonization, the stirrer 10 of the slurry-making equipment can be used to assist in achieving a uniform reaction. It should be noted here that the oxygen and carbon dioxide required by the present utility model can be replaced by flue gas, waste gas, etc. containing oxygen and carbon dioxide. In principle, any gas containing oxygen and carbon dioxide can be used. Only during the process of selection calculation, oxygen and carbon dioxide should be used as the effective cost for calculation, and carbon dioxide solidification can be achieved through this process. By introducing oxygen and carbon dioxide, the pH value of the fly ash will linearly decrease to below 8, which is beneficial to the leaching of heavy metals in the fly ash.
[0034] 2. Transfer the oxidized and carbonized slurry in the pre-dissolution slurry tank 1 into the first-stage water washing tank 21, and add sodium sulfate reagent into the first-stage water washing tank 21 by using the sodium sulfate dosing pump 9. The sodium sulfate reagent is mainly used to react and precipitate the soluble calcium ions in the fly ash, reducing the calcium ion concentration entering the subsequent wastewater treatment. It mainly converts substances such as sulfites, basic hydroxides, and calcium chloride in the fly ash into stable components such as sulfates and carbonates, reducing the fly ash disposal cost and facilitating subsequent resource utilization, while also reducing costs. Then, the water washing wastewater and the first-stage fly ash water washing mud cake are separated. It should be noted here that the sodium sulfate reagent can be by-product sodium sulfate, mirabilite, sodium sulfate anhydrous, etc., or waste salts containing sodium sulfate can be used for substitution to further reduce costs.
[0035] 3. Transfer the slurry in the first-stage water washing tank 21, which has reacted with the sodium sulfate reagent as the main component, into the first-stage solid-liquid separation device 31 to obtain the water washing filtrate and the fly ash water washing filter cake. The fly ash water washing filter cake is injected into the third-stage solid-liquid separation device 33 after passing through the second-stage water washing tank 22, the second-stage solid-liquid separation device 32, and the third-stage water washing tank 23.
[0036] Among them, the washed filtrate obtained from the primary solid-liquid separation device 31 contains substances such as sodium chloride and potassium chloride washed from the fly ash, as well as impurity ions such as heavy metals. Further wastewater treatment is required. After treating the impurity ions, it is sent to the evaporation crystallization unit to crystallize and separate substances such as sodium chloride and potassium chloride, realizing resource utilization. Specifically, the washed filtrate obtained from the primary solid-liquid separation device 31 is passed into the heavy metal removal device 6 to precipitate heavy metals, obtaining heavy metal sludge. After removing impurity ions such as heavy metals, the wastewater is passed into the zero liquid discharge device 7 for processes such as evaporation crystallization to extract components such as sodium chloride, potassium chloride, and calcium chloride in the wastewater, converting them into industrial recycled salt products for resource utilization; at the same time, the treated water of the zero liquid discharge device 7 is re-injected into the tertiary water washing tank 23 through pipe fittings, thereby saving water.
[0037] In addition, the washed filtrate at the liquid discharge port of the tertiary solid-liquid separation device 33 is injected into the pre-dissolution slurry tank 1 through pipe fittings for use as slurry-making water, further saving the use of water resources.
[0038] IV. The fly ash water-washed mud cake at the solid discharge port of the tertiary solid-liquid separation device 33 is introduced into a low-temperature thermal decomposition treatment device for low-temperature thermal decomposition, thereby obtaining thermally decomposed fly ash; specifically, at a temperature below 500°C and in an environment with an oxygen content less than 1%, the purpose of decomposing dioxins is achieved through a certain period of time.
[0039] V. The thermally decomposed fly ash is introduced into the heat treatment furnace 5 for heat treatment at a temperature of 600°C or higher to enhance its activity. The final product of the heat treatment is a low-carbon cementitious material, which has great economic value and can be used as building materials, for example.
[0040] It should be noted that in the present utility model, a multi-stage water washing tank and a multi-stage solid-liquid separation device are adopted, and the discharge port of the zero liquid discharge device 7 is communicated with the water inlet of the tertiary water washing tank 23, and the liquid discharge port of the tertiary solid-liquid separation device 33 is communicated with the water inlet of the pre-dissolution slurry tank 1. Thus, cascade countercurrent water washing is adopted, that is, the relatively clean process water flows into the tertiary water washing tank 23 and flows out of the primary water washing tank, realizing the enrichment of soluble salts and impurity ions.
[0041] In addition, in this solution, the zero liquid discharge device 7 generally adopts an MVR evaporation crystallization system. By virtue of the different saturation points of different salts at different temperatures, different types of salts in the reclaimed water are separated by quality, and industrial salts such as calcium chloride, sodium chloride, and potassium chloride in the wastewater are extracted.
[0042] After being treated by this system, the waste incineration fly ash will finally obtain a low-carbon cementitious material. The dioxin in this material is less than 20 ng-TEQ / kg, the soluble chloride ion is less than 1%, the heavy metal leaching meets the requirements of GB5058.3, and the activity is above 90%.
[0043] Overall, dioxins, heavy metals, soluble salts, etc. in the fly ash can be effectively removed, and substances such as sulfites, alkaline hydroxides, and calcium chloride in the fly ash are converted into stable components such as sulfates and carbonates, realizing the high-quality utilization of the extraction of heavy metals and soluble chlorides, not only reducing the fly ash disposal cost but also facilitating subsequent resource utilization.
[0044] For those skilled in the art, it is obvious that the present utility model is not limited to the details of the above-described exemplary embodiments, and the present utility model can be implemented in other specific forms without departing from the spirit or basic characteristics of the present utility model. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present utility model is defined by the appended claims rather than the above description. Therefore, it is intended to embrace all changes falling within the meaning and scope of the equivalent elements of the claims in the present utility model.
Claims
1. A system for detoxifying and upgrading municipal solid waste incineration fly ash, characterized in that, Comprising: A pre-dissolved slurry tank (1) for dissolving fly ash into a slurry, and an oxygen and carbon dioxide replenishing device (8) is installed on the pre-dissolved slurry tank (1); A water washing device, whose feed inlet is communicated with the discharge outlet of the pre-dissolved slurry tank (1); A sodium sulfate dosing pump (9) for continuously injecting sodium sulfate reagent into the water washing device; A solid-liquid separation device, whose feed inlet is communicated with the discharge outlet of the water washing device, whose liquid discharge outlet is communicated with the heavy metal removal device (6) through pipes, and whose solid discharge outlet is communicated with a low-temperature thermal decomposition device (4); A zero liquid discharge device (7), whose feed inlet is communicated with the waste water discharge outlet of the heavy metal removal device (6) through pipes; A heat treatment furnace (5), whose feed inlet is communicated with the discharge outlet of the low-temperature thermal decomposition device (4).
2. The detoxification and quality improvement treatment system for domestic waste incineration fly ash according to claim 1, characterized in that, The water washing device includes a primary water washing tank (21), a secondary water washing tank (22) and a tertiary water washing tank (23), and the solid-liquid separation device includes a primary solid-liquid separation device (31), a secondary solid-liquid separation device (32) and a tertiary solid-liquid separation device (33); The feed inlet of the primary water washing tank (21) is communicated with the discharge outlet of the pre-dissolved slurry tank (1), and its discharge outlet is communicated with the feed inlet of the primary solid-liquid separation device (31); The feed inlet of the secondary water washing tank (22) is communicated with the solid discharge outlet of the primary solid-liquid separation device (31), and its discharge outlet is communicated with the feed inlet of the secondary solid-liquid separation device (32); The feed inlet of the tertiary water washing tank (23) is communicated with the solid discharge outlet of the secondary solid-liquid separation device (32), and its discharge outlet is communicated with the feed inlet of the tertiary solid-liquid separation device (33), and the solid discharge outlet of the tertiary solid-liquid separation device (33) is communicated with the feed inlet of the low-temperature thermal decomposition device (4).
3. A domestic waste incineration fly ash detoxification and quality improvement treatment system according to claim 2, characterized in that, The discharge outlet of the zero liquid discharge device is communicated with the water inlet of the tertiary water washing tank (23).
4. A domestic waste incineration fly ash detoxification and quality improvement treatment system according to claim 2, characterized in that The liquid discharge outlet of the tertiary solid-liquid separation device (33) is communicated with the water inlet of the pre-dissolved slurry tank (1).
5. A domestic waste incineration fly ash detoxification and quality improvement treatment system according to claim 1, characterized in that, A stirrer (10) is installed in the pre-dissolved slurry tank (1).
6. The detoxification and quality improvement treatment system for municipal solid waste incineration fly ash according to claim 1, wherein When the low-temperature thermal decomposition device (4) works, the thermal decomposition temperature is less than 500 °C, the oxygen content in the device is less than 2%, and the low-temperature thermal decomposition time is 60 min to 120 min.