A waste incineration fly ash flue gas treatment system
The multi-step flue gas purification system solves the environmental pollution problems of heavy metals and dioxins in fly ash from waste incineration, achieves compliant emissions of flue gas and efficient resource recovery, reduces energy consumption and generates economically valuable byproducts.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- HUBEI LUSHENG ENVIRONMENTAL PROTECTION ENG CO LTD
- Filing Date
- 2025-06-23
- Publication Date
- 2026-05-26
AI Technical Summary
Heavy metals, chlorides, and dioxins in fly ash from waste incineration are easily dissolved, causing environmental pollution. Existing technologies are unable to effectively treat and recycle them.
The system employs a sequentially arranged oxygen-enriched side-blowing module, a primary denitrification module, a dioxin control module, a desulfurization module, and a secondary denitrification and dewhitening emission module. Through multiple steps, including oxygen-enriched side-blowing smelting, SNCR denitrification, quench tower cooling, quicklime and activated carbon adsorption, wet scrubbing, and electrostatic precipitator, the flue gas is purified to achieve pollutant removal and resource recovery.
It has achieved compliant emissions of flue gas pollutants and efficient resource recovery, reduced energy consumption, and generated marketable steam and desulfurization gypsum as byproducts, thus ensuring environmental protection and resource utilization.
Smart Images
Figure CN224285468U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the technical field of waste incineration environmental protection devices, and in particular to a waste incineration fly ash flue gas treatment system. Background Technology
[0002] Fly ash is a product collected by flue gas purification systems after waste incineration. It is enriched with heavy metals (Pb, Zn, Cr, Cd, Hg, etc.), dioxins, and high concentrations of soluble chlorides (accounting for 8%-25% of the fly ash weight). Chlorides mainly exist in the form of calcium, sodium, and potassium chlorides, which are easily soluble in water, leading to the release of heavy metals and dioxins into the environment. Therefore, modern waste incinerators need to be equipped with effective flue gas treatment devices to reduce air pollution. Utility Model Content
[0003] The purpose of this invention is to provide a waste incineration fly ash flue gas treatment system that has the effect of reducing flue gas pollution and achieving a high resource recycling rate.
[0004] The above-mentioned technical objective of this utility model is achieved through the following technical solution: comprising an oxygen-enriched side-blowing module, a primary denitrification module, a dioxin control module, a desulfurization module, and a secondary denitrification and whitening emission removal module arranged in sequence.
[0005] The oxygen-enriched side-blown module includes an oxygen-enriched side-blown smelting furnace, and an air inlet is provided on the side of the oxygen-enriched side-blown smelting furnace. The oxygen-enriched side-blown smelting furnace relative to the air inlet is connected to the waste heat boiler in the first-stage denitrification module.
[0006] The primary denitrification module also includes a urea injection device, which is connected to the feed end of the waste heat boiler.
[0007] The dioxin control module includes a quench tower connected to the discharge end of the waste heat boiler.
[0008] The desulfurization module includes a dense phase semi-dry tower, a bag filter, a wet scrubber, and an electrostatic precipitator connected in sequence. The dense phase semi-dry tower is connected to the discharge end of the quench tower.
[0009] The secondary denitrification and whitening emission module includes a flue gas heat exchanger, a pipeline heater, and a secondary denitrification device connected in sequence. The flue gas heat exchanger is connected to an electrostatic precipitator, the electrostatic precipitator is connected to the first feed inlet of the flue gas heat exchanger, the discharge end of the secondary denitrification device is connected to the second feed inlet of the flue gas heat exchanger, and the discharge end of the flue gas heat exchanger is connected to the exhaust stack.
[0010] A further feature of this invention is that an activated carbon powder silo is provided between the quench tower and the dense phase semi-dry tower, and the feed end of the dense phase semi-dry tower is also connected to a slaked lime storage silo.
[0011] A further feature of this invention is that the feed end on one side of the wet scrubber is connected to a limestone storage silo.
[0012] A further feature of this invention is that the feed end of one side of the secondary denitrification device is connected to the urea pyrolysis equipment.
[0013] The beneficial effects of this utility model are:
[0014] 1. The entire equipment revolves around the treatment of flue gas containing high chlorine fly ash from waste. It recovers resources through smelting and then purifies the flue gas through multiple stages to achieve pollutant emissions that meet standards. The various modules and devices work together to achieve the dual goals of resource recovery and environmental protection.
[0015] 2. Oxygen-enriched side-blown smelting utilizes natural gas and oxygen-enriched air (containing 50-70% oxygen) to smelt fly ash from waste at high temperatures, enabling the recovery of valuable metals. Simultaneously, slag and dust are generated, providing initial materials for subsequent processing, making it a key link in resource recovery.
[0016] 3. By setting up a primary denitrification module, the 1100℃ waste gas generated by the oxygen-enriched side-blown smelting furnace enters the waste heat boiler. Softened water and urea solution are used to perform preliminary denitrification through SNCR (selective non-catalytic reduction) on the one hand, and the waste heat boiler recovers heat and produces steam on the other hand. The steam has sales value, realizing the utilization of waste heat resources, and also reducing energy consumption for subsequent flue gas cooling.
[0017] 4. By setting up a dioxin control module, the flue gas from the waste heat boiler enters the quench tower at around 500°C. Inside the quench tower, the flue gas temperature is instantly reduced to around 200°C in 1 second by the action of atomized water to inhibit the regeneration of dioxins. Rapid cooling can inhibit the resynthesis of harmful substances such as dioxins, while creating temperature conditions for subsequent purification.
[0018] 5. By setting up a desulfurization module, the hydrated lime in the hydrated lime storage silo is humidified, and the activated carbon in the activated carbon powder silo is injected into the dense phase semi-dry tower. They come into contact with the flue gas. The hydrated lime neutralizes acidic gases, and the activated carbon adsorbs pollutants such as dioxins and heavy metals, serving as the initial purification stage and producing desulfurization ash. A bag filter can remove dust from the flue gas passing through the dense phase semi-dry tower, intercepting dust and purifying the flue gas while recovering dust, ensuring that subsequent equipment is not affected by dust. A wet scrubbing tower can further purify the flue gas, removing residual acidic substances and fine particles, producing wastewater and deacidification slag, improving flue gas cleanliness. A small amount of desulfurization gypsum (meeting the low chlorine content requirements of cement plants after two stages of dense phase semi-dry desulfurization and dechlorination) is produced as a byproduct and can be sold. An electrostatic precipitator is used to deeply remove droplets and fine pollutants from the flue gas, producing wastewater and ensuring that pollutants are further reduced before the flue gas enters subsequent stages.
[0019] 6. By setting up a two-stage denitrification and whitening emission module, the flue gas heat exchanger is used to regulate the flue gas temperature, ensuring that the flue gas reaches a suitable temperature before entering the two-stage denitrification stage. If the flue gas temperature is insufficient after heat exchange in the flue gas heat exchanger, a pipeline heater can be used to heat the flue gas to 230°C, providing a suitable temperature for SCR denitrification (selective non-catalytic reduction) and ensuring denitrification efficiency. The ammonia produced by the urea pyrolysis equipment can assist the two-stage denitrification stage in deep denitrification under the action of a catalyst, ensuring that the flue gas pollutants meet the standards. After the two-stage denitrification, the flue gas enters the exhaust stack after passing through the flue gas heat exchanger and is discharged in compliance with standards. Attached Figure Description
[0020] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0021] Figure 1 This is a schematic diagram of the structure of this utility model.
[0022] In the diagram, 1. Oxygen-enriched side-blown smelting furnace; 2. Waste heat boiler; 3. Urea injection device; 4. Quenching tower; 5. Dense phase semi-dry tower; 6. Bag filter; 7. Wet scrubber; 8. Electrostatic precipitator; 9. Flue gas heat exchanger; 10. Pipeline heater; 11. Secondary denitrification device; 12. Exhaust stack; 13. Activated carbon powder silo; 14. Slaked lime storage silo; 15. Urea pyrolysis equipment; 16. Limestone storage silo. Detailed Implementation
[0023] The technical solution of this utility model will now be clearly and completely described with reference to specific embodiments. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the scope of protection of this utility model.
[0024] Example: A waste incineration fly ash flue gas treatment system, such as... Figure 1 As shown, the system includes an oxygen-enriched side-blowing module, a primary denitrification module, a dioxin control module, a desulfurization module, and a secondary denitrification and whitening emission module arranged in sequence. The oxygen-enriched side-blowing module includes an oxygen-enriched side-blowing smelting furnace 1. The feed end of the oxygen-enriched side-blowing smelting furnace 1 is located below the discharge end of the conveyor belt. An air inlet is provided on the side of the oxygen-enriched side-blowing smelting furnace 1. The oxygen-enriched side-blowing smelting furnace 1 is connected to the waste heat boiler 2 in the primary denitrification module relative to the air inlet. Waste fly ash, natural gas, or oxygen-enriched air containing 50-70% oxygen is introduced into the smelting furnace. The waste fly ash is smelted at a high temperature of 1300-1350℃ to achieve the recovery of valuable metals.
[0025] The primary denitrification module also includes a urea injection device 3, which is connected to the feed end of the waste heat boiler 2. The 1100°C waste gas generated by the oxygen-enriched side-blown smelting furnace 1 enters the waste heat boiler 2. Using softened water and urea solution, on the one hand, preliminary denitrification is achieved through SNCR (selective non-catalytic reduction), and on the other hand, the waste heat boiler 2 recovers heat and produces steam. The steam has sales value, realizing the utilization of waste heat resources and reducing energy consumption for subsequent flue gas cooling.
[0026] The dioxin control module includes a quench tower 4 connected to the discharge end of the waste heat boiler 2. The flue gas from the waste heat boiler 2 enters the quench tower 4 at about 500°C. Inside the quench tower 4, the flue gas temperature is instantly reduced to about 200°C in 1 second by the action of atomized water to inhibit the regeneration of dioxins. Rapid cooling can inhibit the resynthesis of harmful substances such as dioxins, and at the same time create temperature conditions for subsequent purification.
[0027] The desulfurization module includes a dense-phase semi-dry tower 5, a bag filter 6, a wet scrubber 7, and an electrostatic precipitator 8 connected in sequence. The dense-phase semi-dry tower 5 is connected to the discharge end of the quench tower 4. The hydrated lime in the hydrated lime storage silo 14 and the activated carbon in the activated carbon powder silo 13 both enter the dense-phase semi-dry tower 5 and come into contact with the flue gas. The hydrated lime neutralizes the acidic gases, and the activated carbon adsorbs pollutants such as dioxins and heavy metals, which is the preliminary purification stage of pollutants, producing desulfurization ash. The bag filter 6 can remove dust from the flue gas passing through the dense-phase semi-dry tower 5, intercepting dust and purifying the flue gas. The system simultaneously treats flue gas and recovers dust, ensuring that subsequent equipment is protected from dust contamination. A wet scrubbing tower further purifies the flue gas, removing residual acidic substances and fine particles, producing wastewater and desulfurization slag, thus improving flue gas cleanliness. A small amount of desulfurization gypsum (which meets the low chlorine content requirements of cement plants after two-stage dense-phase semi-dry desulfurization and dechlorination) is also produced and sold. An electrostatic precipitator (8) is used to deeply remove droplets and fine pollutants from the flue gas, producing wastewater and ensuring that pollutants are further reduced before the flue gas enters subsequent stages. During this process, the flue gas temperature gradually decreases.
[0028] The secondary denitrification and whitening emission module includes a flue gas heat exchanger 9, a pipeline heater 10, and a secondary denitrification device 11 connected in sequence. The flue gas heat exchanger 9 is connected to an electrostatic precipitator 8, which is connected to the first inlet of the flue gas heat exchanger 9. The discharge end of the secondary denitrification device 11 is connected to the second inlet of the flue gas heat exchanger 9, and the discharge end of the flue gas heat exchanger 9 is connected to the exhaust stack 12. The flue gas heat exchanger 9 is used to regulate the flue gas temperature, ensuring that the flue gas reaches a suitable temperature before entering the secondary denitrification stage. If the flue gas temperature is insufficient after heat exchange in the flue gas heat exchanger 9, the pipeline heater 10 can heat the flue gas to 230°C, providing a suitable temperature for SCR denitrification (selective non-catalytic reduction) and ensuring denitrification efficiency. The ammonia produced by the urea pyrolysis equipment 15 can assist in the secondary denitrification stage under the action of a catalyst for deep denitrification, ensuring that the flue gas pollutants meet the standards. The flue gas after secondary denitrification passes through the flue gas heat exchanger 9 and then enters the exhaust stack 12 for emission in compliance with standards.
[0029] like Figure 1 As shown, an activated carbon powder silo 13 is also provided between the quench tower 4 and the dense phase semi-dry tower 5, and the feed end of the dense phase semi-dry tower 5 is also connected to the hydrated lime storage silo 14.
[0030] like Figure 1 As shown, the feed end on one side of the wet scrubber 7 is connected to the limestone storage silo 16.
[0031] like Figure 1 As shown, the feed end of the secondary denitrification unit 11 is connected to the urea pyrolysis equipment 15.
[0032] Working principle of a waste incineration fly ash flue gas treatment system:
[0033] Oxygen-enriched side-blown smelting utilizes natural gas and oxygen-enriched air (containing 50-70% oxygen) to smelt waste fly ash at high temperatures, achieving the recovery of valuable metals, while generating slag and dust, providing initial materials for subsequent processing;
[0034] The 1100℃ waste gas generated by the oxygen-enriched side-blown smelting furnace 1 enters the waste heat boiler 2. Softened water and urea solution are used to perform preliminary denitrification through SNCR (selective non-catalytic reduction) on the one hand, and waste heat boiler 2 recovers heat and produces steam on the other hand. The steam has sales value, realizing the utilization of waste heat resources and reducing energy consumption for subsequent flue gas cooling.
[0035] The flue gas from the waste heat boiler 2 enters the quench tower 4 at around 500°C. Inside the quench tower 4, the flue gas temperature is instantly reduced to around 200°C in 1 second by the action of atomized water to inhibit the regeneration of dioxins. Rapid cooling can inhibit the resynthesis of harmful substances such as dioxins, and at the same time create temperature conditions for subsequent purification.
[0036] After the slaked lime in the slaked lime storage silo 14 is humidified, the activated carbon in the activated carbon powder silo 13 is injected into the dense phase semi-dry tower 5, where it comes into contact with the flue gas. The slaked lime neutralizes the acidic gas, and the activated carbon adsorbs pollutants such as dioxins and heavy metals, which is the initial purification stage of pollutants, producing desulfurization ash. The flue gas coming out of the dense phase semi-dry tower 5 enters the bag filter 6, which can remove dust from the flue gas after passing through the dense phase semi-dry tower 5, intercepting dust, purifying the flue gas and recovering dust at the same time, ensuring that subsequent equipment is not affected by dust. Then it enters the wet scrubbing tower, which can further purify the flue gas, remove residual acidic substances, fine particles, etc., producing wastewater and deacidification slag, improving the cleanliness of the flue gas. Then it enters the electrostatic precipitator 8, which deeply removes mist droplets and fine pollutants in the flue gas, producing wastewater, ensuring that the pollutants in the flue gas are further reduced before entering the subsequent stages.
[0037] The flue gas exiting the electrostatic precipitator 8 is at a relatively low temperature and enters the flue gas heat exchanger 9 to regulate its temperature, ensuring it reaches a suitable temperature before entering the secondary denitrification stage. If the flue gas temperature is insufficient after heat exchange in the heat exchanger 9, the flue gas can be heated to 230°C using the pipeline heater 10, providing a suitable temperature for SCR (Selective Non-Catalytic Reduction) denitrification and ensuring denitrification efficiency. The ammonia produced by the urea pyrolysis equipment 15 can assist in the secondary denitrification stage under the action of a catalyst for deep denitrification, ensuring that the flue gas pollutants meet the standards. After secondary denitrification, the flue gas enters the exhaust stack 12 after passing through the flue gas heat exchanger 9 and is discharged in compliance with standards.
Claims
1. A system for treating waste incineration fly ash flue gas, characterized by: It includes, in sequence, an oxygen-enriched side-blowing module, a primary denitrification module, a dioxin control module, a desulfurization module, and a secondary denitrification and whitening emission removal module. The oxygen-enriched side-blown module includes an oxygen-enriched side-blown smelting furnace (1), and an air inlet is provided on the side of the oxygen-enriched side-blown smelting furnace (1). The oxygen-enriched side-blown smelting furnace (1) relative to the air inlet is connected to the waste heat boiler (2) in the first-stage denitrification module. The primary denitrification module also includes a urea injection device (3), which is connected to the feed end of the waste heat boiler (2); The dioxin control module includes a quench tower (4) connected to the discharge end of the waste heat boiler (2); The desulfurization module includes a dense phase semi-dry tower (5), a bag filter (6), a wet scrubber (7), and an electrostatic precipitator (8) connected in sequence. The dense phase semi-dry tower (5) is connected to the discharge end of the quench tower (4). The secondary denitrification and dewhitening emission module includes a flue gas heat exchanger (9), a pipeline heater (10), and a secondary denitrification device (11) connected in sequence. The flue gas heat exchanger (9) is connected to an electrostatic precipitator (8). The electrostatic precipitator (8) is connected to the first feed inlet of the flue gas heat exchanger (9). The discharge end of the secondary denitrification device (11) is connected to the second feed inlet of the flue gas heat exchanger (9). The discharge end of the flue gas heat exchanger (9) is connected to the exhaust stack (12).
2. The waste incineration fly ash flue gas treatment system according to claim 1, characterized in that: An activated carbon powder silo (13) is also provided between the quench tower (4) and the dense phase semi-dry tower (5), and the feed end of the dense phase semi-dry tower (5) is also connected to the slaked lime storage silo (14).
3. The waste incineration fly ash flue gas treatment system according to claim 2, characterized in that: The feed end of the wet scrubber (7) is connected to the limestone storage silo (16).
4. The waste incineration fly ash flue gas treatment system according to claim 3, characterized in that: The feed end of the secondary denitrification device (11) is connected to the urea pyrolysis equipment (15).