Multi-purpose comprehensive utilization system for flue gas of garbage incinerator

Abstract

The invention discloses a multipurpose comprehensive utilization system for flue gas of a garbage incinerator, and relates to the technical field of solid waste treatment and resource recovery. After steam generated by a waste heat boiler drives a generator set, medium-temperature and low-temperature flue gas is sequentially guided into a sludge drying system for heat energy coupling utilization; in the purification section, a synergistic removal process is adopted, and trapped pollutants are converted into ammonium sulfate fertilizer raw materials while acid gas and dioxin are efficiently removed; finally, the fly ash rich in heavy metal is guided into a melting system, and inert building material aggregate is formed through high-temperature vitrification. According to the integrated system, the limitation of traditional quality-divided treatment is broken through, the three targets of deep recovery of flue gas waste heat, collaborative resource conversion of pollutants and safe treatment of fly ash are achieved, the operation cost is greatly reduced, additional economic values are created, and a win-win comprehensive solution of environmental benefits and economic benefits is provided for a waste incineration plant.

Description

Technical Field

[0001] This invention relates to the field of solid waste treatment and resource recycling technology, and in particular to a multi-purpose integrated utilization system for flue gas from a waste incinerator. Background Technology

[0002] In recent years, integrated treatment technologies for waste incineration flue gas in the solid waste treatment sector have faced three major challenges: low energy recovery efficiency, high pollutant control costs, and insufficient by-product resource utilization. Existing technologies generally employ a discrete treatment process: high-temperature flue gas is directly fed into the purification system after being used for power generation in a waste heat boiler, leaving the medium- and low-temperature waste heat (200-300℃) largely unutilized; acidic gases, dioxins, and heavy metals require separate treatment in multi-stage towers, with equipment investment accounting for over 35% of the total cost of the incineration plant; and fly ash, as hazardous waste, requires solidification and landfill, with disposal costs exceeding 1,000 yuan per ton. In particular, the waste heat recovery rate is typically less than 65%, while dioxin control relies on excessive activated carbon injection (consumption > 200 mg / Nm³), making it difficult to balance operational economics and environmental sustainability.

[0003] A typical scheme of "A High-Temperature Flue Gas Treatment System for a Waste Incinerator" disclosed in Chinese Patent CN116951422A includes: an incinerator, a waste heat boiler, a desulfurization reaction tower, a cyclone separator, and a wind-driven sorting device. The incinerator, cyclone separator, waste heat boiler, and desulfurization reaction tower are connected sequentially. The cyclone separator has a high-temperature flue gas inlet and a dechlorinating agent inlet on its side. The wind-driven sorting device is connected to the bottom of the cyclone separator to separate solid particles collected at the bottom of the cyclone separator and to re-inject the dechlorinating agent separated from the solid particles into the cyclone separator. The high-temperature flue gas output from the incinerator first enters the cyclone separator for dechlorination and dust removal, then enters the waste heat boiler for waste heat utilization, and finally enters the desulfurization reaction tower to undergo a desulfurization reaction with quicklime slurry spray. The desulfurized flue gas then enters the dust removal system for further purification before being discharged. This invention has advantages such as compact structure, high dechlorination efficiency, reduced ash accumulation and slagging rate in the waste heat boiler, and improved boiler heat exchange efficiency.

[0004] Considering the current technological bottlenecks, the core problem urgently needing to be solved in this field is: how to construct an energy-matter synergistic conversion system to simultaneously achieve deep recovery of waste heat from flue gas, synergistic resource conversion of multiple pollutants, and high-value utilization of fly ash within a single system. Specifically, three major technological hurdles need to be overcome: 1) High-efficiency thermal energy extraction technology for medium-low temperature flue gas (180-250℃) to avoid the problems of easy clogging and inefficiency in traditional heat exchangers; 2) A simultaneous removal mechanism for acidic gases, dioxins, and heavy metals, replacing the current complex multi-tower series process; 3) A targeted recovery process for heavy metals during the fly ash melting and solidification process to address the environmental risks and economic burdens of traditional landfill methods. This requires a fundamental restructuring of the system design logic and the establishment of a closed-loop coupling mechanism between material flow and energy flow. Summary of the Invention

[0005] In view of the aforementioned existing problems, the present invention is proposed.

[0006] Therefore, this invention provides a multi-purpose integrated utilization system for flue gas from a waste incinerator to solve the existing waste...

[0007] The problems in waste incineration flue gas treatment include low energy utilization, dispersed pollutant control units, and insufficient exploitation of by-product value.

[0008] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0009] In a first aspect, the present invention provides a multi-purpose comprehensive utilization system for flue gas from a waste incinerator, which includes a flue gas energy cascade utilization module, a pollutant synergistic removal and resource utilization module, and a fly ash high-temperature melting and solidification module;

[0010] The flue gas energy cascade utilization module is configured to divert the high-temperature flue gas (>850°C) generated by the incinerator to the waste heat boiler for power generation, and the medium- and low-temperature flue gas (180~250°C) to the sludge drying system.

[0011] The pollutant co-removal and resource utilization module is configured to receive flue gas after energy recovery at 120-180°C, and simultaneously remove acidic gases, heavy metals and dioxins in a single reaction tower through a swirl atomization coupled adsorption process, and convert the reaction products into ammonium sulfate crystals.

[0012] The fly ash high-temperature melting and solidification module is configured to mix the fly ash captured by the bag filter with a melting aid, and then perform arc melting in a reducing atmosphere at ≥1400℃ to form a glassy inert building material.

[0013] As a preferred embodiment of the multi-purpose comprehensive utilization system for waste incinerator flue gas described in this invention, the intelligent diversion device in the flue gas energy cascade utilization module adopts a dual-channel pneumatic regulating valve group as the core actuator. This valve group is cast from high-temperature resistant 310S stainless steel, with a valve plate thickness of 20mm and a 0.5mm thick tungsten carbide wear-resistant layer sprayed on the surface. The valve shaft is equipped with a magnetostrictive displacement sensor to provide real-time feedback on the opening position, achieving a control accuracy of ±0.5°.

[0014] During operation, the valve assembly receives interlock signals from the temperature sensor and the sludge treatment system: when the K-type thermocouple installed at the outlet of the waste heat boiler detects that the flue gas temperature is in the range of 180~250℃, the valve plate angle is dynamically adjusted by the PLC controller, so that the proportion of flue gas entering the sludge drying system is continuously adjustable between 30% and 70%; at the same time, based on the moisture content data fed back by the sludge silo weighing module, the corresponding relationship between the flue gas flow rate and the sludge feeding rate is automatically matched to achieve precise heat energy distribution of 1200~1500m³ of flue gas per ton of wet sludge.

[0015] The sludge drying system uses a multi-stage spiral feeder dryer as its core equipment. Its cylinder is made of double-layer 316L stainless steel plate, with an inner layer plate thickness of 8mm and laser-welded axial finned tube bundles. The fins are 15mm high, 10mm apart, and arranged in a 45° staggered pattern to form a flue gas turbulence channel.

[0016] After being fed into the feed inlet, the wet sludge undergoes three stages under the mechanical propulsion of the variable-pitch screw blades: the 300mm wide pitch in the feeding section forms a 20-30mm thin layer of sludge, increasing the contact area with flue gas; the 150mm narrow pitch in the middle section applies a linear pressure of 0.3MPa to the sludge, disrupting the colloidal structure and releasing bound water; and the 250mm standard pitch in the discharge section ensures uniform discharge of the dried products.

[0017] The dryer shell is equipped with an insulation jacket, through which saturated steam at a pressure of 0.6 MPa and a temperature of 165°C is introduced. The heat loss at the end of the cylinder is compensated by thermal radiation, ensuring that the sludge temperature at the discharge port remains stable above 75°C.

[0018] The flue gas flows laterally across the finned tube bundle at a design velocity of 4 m / s. Under turbulent conditions with a Reynolds number Re > 5000, forced convection heat transfer between the sensible heat of the flue gas and the sludge particles is achieved, with a heat transfer efficiency of 85 W / (m²·K). Ultimately, the sludge moisture content is reduced from 80% to below 12%.

[0019] As a preferred embodiment of the multi-purpose comprehensive utilization system for waste incinerator flue gas described in this invention, the variable pitch screw shaft of the multi-stage spiral pusher dryer is integrally forged from high-strength duplex steel S31803, with a main shaft diameter of 200mm and a 1.5mm thick Stellite alloy wear-resistant layer welded to the surface. The thickness of the spiral blades gradually changes from 12mm to 20mm from the feed end to the discharge end. The feed section is provided with a 300mm equidistant screw pitch to form a fluffy chamber with a volume of 0.8m³, so that the wet sludge with an initial moisture content of 80% is evenly spread on the bottom of the conveying trough with a thickness of 15~20cm.

[0020] The pitch of the middle section is sharply reduced to 150mm while maintaining a compression zone of 5 times the diameter. The edges of the spiral blades are machined into 45° acute-angle cutting edges. At a speed of 3~5r / min, a linear mechanical pressure of 0.35MPa is applied to the sludge to forcefully crush the cell walls of microorganisms in the sludge and release bound water. The inner wall of this section is fitted with flow-blocking ribs with a height of 10mm. The ribs are arranged in a spiral with a spacing of 50mm to enhance the reverse shearing effect.

[0021] The discharge section has an extended screw pitch of 250mm and is equipped with a conical discharge hood. Under the combined action of mechanical pushing and gravity settling, it forms granular dried products with a particle size of 5~10mm. The moisture content gradient fluctuation does not exceed ±2%, and is finally stably controlled in the range of 12%~15%.

[0022] The dryer shell is wrapped with a double layer of aluminum silicate insulation to form a jacket structure. Saturated steam with a pressure of 0.4MPa and a temperature of 170℃ is introduced into the jacket. The steam inlet is located within 2m of the last section of the cylinder and flows through the jacket in a counter-current manner. The heat loss at the end caused by the temperature decay of the flue gas is compensated by heat conduction, ensuring that the material temperature at the outlet is kept constant at 70±5℃.

[0023] As a preferred embodiment of the multi-purpose comprehensive utilization system for waste incinerator flue gas described in this invention, the reaction tower of the pollutant synergistic removal and resource recovery module adopts a three-section integrated structure. The tower body is formed by rolling and welding 6mm thick titanium-steel composite plate. The contraction angle of the bottom Venturi acceleration section is designed to be 25°, and the throat diameter is reduced to 1 / 3 of the inlet section, so that the flue gas velocity increases sharply from 8m / s to 28m / s. At the same time, lime slurry is injected at a pressure of 0.3MPa through an annular distributor. The droplet particle size D50=50μm, forming a mixing field with gas-liquid turbulence intensity >0.4 at the throat.

[0024] The central swirling atomization layer is equipped with six radially symmetrical ultrasonic atomization units, each equipped with 12 piezoelectric ceramic nozzles with a frequency of 1.7MHz. Activated carbon-nano titanium dioxide composite adsorbent is sprayed at a dosage of 0.8g / Nm³. The nano titanium dioxide loading in the adsorbent is 15wt%, with a particle size distribution D90≤8μm. The spray cone angle is 60°, covering more than 95% of the tower cross-section. Swirling adsorption clouds are formed during the flue gas rise, with a residence time ≥4s.

[0025] Three layers of gradient sieve plates with varying apertures are arranged at the top. The bottom sieve plate has an opening rate of 40% and an aperture of 3mm, the middle sieve plate has an opening rate of 35% and an aperture of 2mm, and the top sieve plate has an opening rate of 30% and an aperture of 1mm. The sieve plates are spaced 300mm apart and arranged in a staggered 30° rotation. A 10% concentration of ammonium sulfate mother liquor is evenly distributed above the sieve plates through an overflow trough. The liquid film thickness is 2~3mm, which allows the flue gas to be divided into microbubble groups by the liquid film when it passes through the sieve holes at a flow rate of 7m / s. The gas-liquid contact specific surface area reaches 1200m² / m³.

[0026] The crystallization tank at the bottom of the tower is equipped with a hyperboloid guide tube. A seed generator with an adjustable speed of 10~30 r / min is installed at the bottom of the guide tube. The supersaturation of the slurry is monitored in real time by an online conductivity meter and the amount of ammonium sulfate mother liquor sprayed is adjusted accordingly to maintain the supersaturation coefficient of the crystallization zone stable between 1.08 and 1.12. Finally, cubic ammonium sulfate crystals with a particle size of 1.2±0.3 mm are precipitated on the tank wall.

[0027] As a preferred embodiment of the multi-purpose comprehensive utilization system for waste incinerator flue gas described in this invention, the adsorbent regeneration unit of the pollutant synergistic removal and resource utilization module includes a microwave desorption system and a pneumatic circulation system. The microwave desorption chamber adopts a rectangular multimode resonant cavity design with a cavity size of 1200×800×600mm. The inner wall is covered with a 2mm thick sintered alumina ceramic layer. The top is arrayed with 12 sets of magnetron emission sources, each set of magnetrons with a power of 1.2kW and a working frequency of 2450±50MHz. A high-temperature resistant silicon carbide conveyor belt is installed at the bottom of the cavity. The conveyor belt running speed is adjustable from 0.5 to 2m / min. The saturated adsorbent forms a uniform material layer with a thickness of 30mm on the conveyor belt.

[0028] The desorption process employs a three-stage temperature control strategy: the feeding stage starts at 40% power to preheat the material to 80~100℃; the middle stage starts at 100% power to raise the temperature to 450±10℃ within 3 minutes to achieve desorption of organic matter; the discharge stage reduces the power to 60% and maintains 300℃ to prevent the adsorbent from becoming embrittled due to sudden cooling; the gaseous pollutants generated by desorption are introduced into the bypass combustion chamber through the negative pressure gas collection hood, where they stay in the 1100℃ high-temperature zone for 2.5 seconds to completely decompose dioxins;

[0029] The regenerated adsorbent is cooled to below 80°C by a spiral cooler and then enters the Venturi injector of the pneumatic circulation system. The flow velocity at the throat of the injector reaches 25 m / s. The adsorbent particles are transported to the storage silo using 0.6 MPa compressed air. A fluidized bed homogenizer is installed at the bottom of the storage silo, and dry air with a flow rate of 50 m³ / h is introduced to maintain the loose state of the adsorbent.

[0030] The circulation system is equipped with an online activity detector, which monitors the decay rate of the adsorbent's specific surface area in real time using laser scattering. When the detected value is lower than 80% of the initial value, the replenishment program is automatically started to ensure that the adsorbent activity of the system is maintained above 95%, and the energy consumption of the entire regeneration process is ≤0.8kWh / kg adsorbent.

[0031] As a preferred embodiment of the multi-purpose comprehensive utilization system for waste incinerator flue gas described in this invention, the pretreatment unit of the high-temperature melting and solidification module for fly ash adopts a two-stage mixing process. In the first stage, fly ash collected by the electrostatic precipitator and melting aid, SiO2:Al2O3:CaO=52:30:18, are added to a conical mixer at a mass ratio of 1:0.28. The mixture is dry-mixed for 5 minutes at a speed of 15 r / min to form a basic mixture. In the second stage, sodium lignosulfonate solution accounting for 12% of the total amount is added as a binder. The mixture is wet-mixed for 8 minutes at a speed of 45 r / min in a twin-shaft paddle mixer. Finally, it is formed into a cylindrical blank with a diameter of Φ22×35mm by a hydraulic pressing machine. The density of the blank is controlled at 1.8±0.1g / cm³ and the compressive strength is ≥5MPa.

[0032] The melting unit adopts a vertical DC electric arc furnace, with the furnace chamber lined with corundum refractory material, Al2O3≥95%. The furnace body is divided into upper and lower zones: the lower zone is a reduction melting pool, where three Φ300mm graphite electrodes are inserted into the melting pool at 120°, and the electrode current density is maintained at 85A / cm². A mixture of natural gas and oxygen in a volume ratio of 1:0.6 is introduced to stabilize the melting pool temperature at 1460±20℃ and the CO concentration at 12 vol%. The fly ash billet stays in this zone for 25 minutes to achieve the reduction and volatilization of heavy metals.

[0033] The upper zone is a rapid cooling and recovery zone. 24 sets of ammonia water injectors are arranged circumferentially on the side wall of the furnace top. The injection pressure is 0.4MPa and the atomization angle is 60°. 10% concentration ammonia water is injected into the 850-900℃ flue gas zone at a flow rate of 120L / min, so that the volatilized lead, cadmium and zinc chlorides are converted into metal ammonium salt particles. A quencher is installed at the top of this zone. Liquid nitrogen at -20℃ is introduced to cool the flue gas to below 600℃ within 0.3 seconds to inhibit the resynthesis of dioxins.

[0034] The molten glass is discharged through the overflow port into the water quenching tank, where hot water at 80°C is circulated and impacted with the molten flow at a flow rate of 10 m / s. The water quenching ratio is controlled at 1:1.2, producing glassy aggregate with a particle size of 4~9 mm. The total content of SiO2+Al2O3+CaO is >85%, and the leaching concentrations of heavy metals Pb and Cd are less than 0.05 mg / L and 0.01 mg / L, respectively.

[0035] Volatile heavy metal ammonium salts are collected by a bag filter and then enter a dilute sulfuric acid dissolution tank. The solution is then electrowinning to recover zinc ingots and lead-cadmium alloys with a purity of 99.5%.

[0036] As a preferred embodiment of the multi-purpose comprehensive utilization system for waste incinerator flue gas described in this invention, the molten product processing of the high-temperature melting and solidification module for fly ash includes a dual path of glass resource utilization and directional heavy metal recovery. When the molten glass is treated in the water quenching tank, a stepped cooling process is adopted: the high-temperature glass flow first enters the primary quenching chamber and is mixed with 80°C circulating hot water at a volume ratio of 10:1. The water flow velocity of 12m / s impacts the glass flow, causing it to initially break up. Then it falls into the secondary vortex chamber, where three sets of tangential water inlet pipes are set up to form a swirling flow field with a Reynolds number Re > 12000. Under the action of centrifugal force, the glass is broken into 4~8mm particles.

[0037] After quenching, the glass particles are separated by a dewatering screen and then subjected to two-stage countercurrent rinsing to remove surface alkali metal salts. The pH value of the rinsing water is controlled at 6.5~7.0, and finally an inert aggregate with SiO2+Al2O3 content >75% is obtained. The TCLP leaching concentrations of lead, chromium and nickel are less than 0.03mg / L, 0.02mg / L and 0.05mg / L, respectively.

[0038] The heavy metal recovery system adopts a multi-stage integrated design: flue gas containing heavy metal ammonium salts is quenched and then enters a pulse bag filter. The filter bag surface is covered with a PTFE membrane with a pore size of 0.5μm, and the collection efficiency is >99.9%. The collected metal ammonium salt dust is introduced into a dissolution tank. A 15% dilute sulfuric acid solution is added to the tank and the liquid-solid ratio is maintained at 5:1. The tank is stirred at 50℃ for 30 minutes to fully dissolve zinc ammonium salt and lead ammonium salt.

[0039] After insoluble substances are removed by a precision filter, the solution enters a four-chamber electrowinning cell. The anode is a titanium-based iridium-tantalum coated plate, and the cathodes are stainless steel plates and aluminum plates, respectively. Selective electrowinning is carried out under the conditions of current density of 300 A / m² in the zinc region and 150 A / m² in the lead-cadmium region.

[0040] Electrowinning product processing: The zinc cathode is stripped every 8 hours and then vacuum-cast to obtain zinc ingots with a purity of 99.8%. The lead-cadmium deposits are dissolved in dilute nitric acid and then separated by solvent extraction. The organic phase is selected from the 20% tributyl phosphate-kerosene system, and the final product is a lead-cadmium alloy with Pb:Cd=85:15 and 99.5% pure cadmium.

[0041] The wastewater from the entire process is neutralized and precipitated before being reused in the water quenching system, achieving a heavy metal recovery rate of >92% for zinc, >95% for lead, and >88% for cadmium, with no secondary waste discharge.

[0042] As a preferred embodiment of the multi-purpose comprehensive utilization system for waste incinerator flue gas described in this invention, the intelligent control system constructs a three-layer monitoring-execution architecture. K-type armored thermocouples and anti-clogging Pitot tubes are installed at the waste heat boiler outlet, sludge dryer inlet, and pollutant removal tower of the flue gas energy cascade utilization module to collect temperature and pressure data in real time. A current transformer and an infrared thermometer are integrated on the electrode column of the fly ash melting furnace to continuously monitor the melting state.

[0043] The core control cabinet adopts a redundant PLC system with a main processor processing cycle of ≤10ms and a built-in multivariable coupled control algorithm: when the flue gas calorific value fluctuation is detected to exceed the set threshold, the material-energy balance compensation mechanism is automatically activated. First, the opening of the flue gas diversion valve is adjusted at a rate of 10% / s to maintain the sludge dryer inlet temperature at 185±5℃. At the same time, the activated carbon injection amount is proportionally corrected, with a 0.05g / Nm³ change in injection amount corresponding to every 100kcal / Nm³ change in calorific value. The power of the melting furnace is dynamically adjusted based on the online analysis results of the fly ash heavy metal content. For every 100mg / kg increase in lead content, the electrode current is increased by 2%.

[0044] Hard interlock protection is set up for sudden system failures: when the pressure difference of the bag filter is >1500Pa, the adsorbent injection is immediately cut off and the bypass flue is started; when the temperature of the melting furnace is below 1400℃ for 30 seconds, auxiliary fuel is automatically injected, and the natural gas flow rate is adjustable from 0 to 50m³ / min; when the oxygen content of the flue gas exceeds 8%, the feed valve of the sludge dryer is closed in conjunction with the system.

[0045] All monitoring data are transmitted to the central monitoring station via an industrial fiber optic ring network. The station is equipped with a 3D visualization platform that renders the flue gas flow trajectory and temperature field distribution in real time. The operation interface is embedded with a fault diagnosis expert database, and an emergency response plan is automatically popped up for abnormal data. The system response delay is ≤200ms.

[0046] The control program is equipped with a self-learning function: it automatically generates an operation optimization report every 1000 hours of operation, and corrects the key parameter settings based on historical data, so that the system can maintain the pollutant removal efficiency fluctuation range of <±1.5% even under seasonal changes in waste composition.

[0047] As a preferred embodiment of the multi-purpose comprehensive utilization system for waste incinerator flue gas described in this invention, the heat energy recovery optimization method achieves deep energy utilization through a three-stage heat exchange of steam, flue gas, and air. The water vapor generated by the sludge drying system, with a pressure of 0.15 MPa and a temperature of 75~80℃, enters the ejector mixer after the droplets are removed by the demister. The diameter of the mixer throat is designed to be 1 / 4 of the inlet pipe, and the steam flow is ejected at a flow rate of 20 m / s, so that it is fully mixed with the flue gas at 160~170℃ in the front section of the SCR reactor in the Venturi section.

[0048] The temperature of the mixed flue gas is monitored in real time by a thermocouple array. When the temperature drops below 190℃, the steam injection valve is automatically activated. Through PID regulation with a proportional band of 80% and an integral time of 60s, the flue gas temperature is stabilized at 195±3℃, within the optimal activity window of the denitrification catalyst. This temperature control accuracy is more than 50% higher than that of conventional flue gas heat exchangers.

[0049] After the SCR reaction, the flue gas at 230-250℃ enters the plate heat exchanger to recover waste heat. The heat exchange plates are made of 0.5mm thick 254SMO super stainless steel laser welded and formed with a plate corrugation angle of 60°, forming cross flow channels to make the flue gas velocity 8m / s and the air velocity 12m / s, with a heat exchange area density of 250m² / m³.

[0050] The air side adopts a two-stage preheating design: cold air is first preheated to 110°C in the low-temperature section of the heat exchanger, and then heated to 150°C in the high-temperature section. The preheated air is delivered in two routes: 80% of the flow from the main route is connected to the primary air system of the incinerator, and 20% of the flow from the branch route is sent to the combustion air duct of the fly ash melting furnace.

[0051] The heat exchanger condensate collection system is equipped with an online pH adjustment unit. When the pH of the condensate is detected to be less than 5.5, 10% NaOH solution is automatically injected to neutralize it and maintain the pH value at 6.8~7.2, which meets the closed-loop recycling standard. The entire heat recovery system increases the total thermal efficiency to 86.5%, which is 12 percentage points higher than that of conventional incineration plants.

[0052] As a preferred embodiment of the multi-purpose comprehensive utilization system for waste incinerator flue gas described in this invention, the optimization of the ammonium sulfate crystallization process is achieved through precise control of crystallization kinetics. The volume of the conical crystallization tank at the bottom of the reaction tower is designed to be 8m³. The tank wall adopts a double-layer structure: the inner liner is a 4mm thick Hastelloy C276 plate, and the outer jacket is filled with 25℃ circulating cooling water to maintain the temperature gradient of the tank wall. A hyperboloid guide tube is vertically installed at the center of the tank. The guide tube has an upper diameter of 800mm, a lower diameter of 500mm, and a height of 1200mm. The tube wall has 120 spirally distributed Φ10mm guide holes with an inclination angle of 45°.

[0053] A variable frequency seed generator is installed at the bottom of the guide tube. The generator disc has a diameter of 400 mm and 48 wedge-shaped grooves with a depth of 5 mm evenly distributed on the edge. It continuously releases ammonium sulfate seed crystals with a particle size of 0.2~0.3 mm at a rotation speed of 20 r / min. The seed crystal addition amount is 0.8 wt% of the crystallization mother liquor flow rate.

[0054] The supersaturation control adopts a dual-parameter feedback mechanism of conductivity and density: an online conductivity meter and a vibrating density meter are installed at the outlet of the guide tube to monitor the changes in the physical properties of the slurry in real time. When the conductivity exceeds 180 mS / cm and the density is >1150 kg / m³, the PLC system automatically increases the opening of the ammonium sulfate mother liquor feed valve at a rate of 5% / s to stabilize the supersaturation in the metastable range of 1.10 ± 0.02.

[0055] The crystallized product is fed into a horizontal pusher centrifuge via an overflow weir. The centrifuge drum diameter is 1000 mm, the differential speed is 15 r / min, and it is operated under a separation factor of 800. The water content of the separated ammonium sulfate crystals is ≤0.5%. After being treated in a fluidized bed dryer with hot air at 80℃ for 10 minutes, a cubic crystal product of 1.0~1.5 mm is obtained.

[0056] The centrifuged mother liquor is introduced into a neutralization and adjustment tank, which is equipped with a pH electrode and an ultrasonic mixer. When the pH is <6.3, a metering pump is started to inject 10% ammonia water. When the pH is >7.2, 30% dilute sulfuric acid is added. Finally, the pH of the mother liquor is precisely controlled at 6.8±0.1. After the adjusted mother liquor is filtered to remove suspended solids, it is returned to the desulfurization system for recycling. The mother liquor reuse rate is >95% and there is no risk of crystallization salt accumulation.

[0057] In a second aspect, the present invention provides a computer device, including a memory and a processor, wherein the memory stores a computer program, and the computer program, when executed by the processor, implements any step of the multi-purpose integrated utilization system for waste incinerator flue gas as described in the first aspect of the present invention.

[0058] Thirdly, the present invention provides a computer-readable storage medium having a computer program stored thereon, wherein: when the computer program is executed by a processor, it implements any step of the multi-purpose integrated utilization system for waste incinerator flue gas as described in the first aspect of the present invention.

[0059] The beneficial effects of this invention are:

[0060] This invention fundamentally breaks through the technical bottleneck of traditional waste incineration flue gas treatment by constructing a three-dimensional coupled system of "energy cascade utilization - pollutant synergistic conversion - high-value utilization of fly ash". In terms of energy recovery, the innovative intelligent diversion device combined with a multi-stage spiral dryer directly utilizes the sensible heat of the 180-250℃ medium-low temperature flue gas for sludge drying. Compared to conventional heat exchanger recovery methods, the heat transfer efficiency is increased from 60% to 92%. Combined with the optimized process of steam waste heat recovery and SCR denitrification, the overall system thermal efficiency exceeds 86.5%, translating to an increase of 85 kWh of power generation per ton of waste. In the field of pollutant control, the unique three-stage reaction tower integrates cyclone atomization adsorption and sieve plate membrane reaction technology, simultaneously completing desulfurization and denitrification (efficiency > 98%), dioxin decomposition (decomposition rate > 97%), and... Heavy metal capture (removal rate >95%) reduces equipment footprint by 40% while activated carbon consumption drops to below 80 mg / Nm³. Furthermore, microwave regeneration technology enables up to 20 cycles of adsorption, saving over 3 million yuan annually in adsorption costs. Addressing the challenge of fly ash disposal, the fly ash pressing and melting process achieves efficient volatilization and separation of heavy metals in a reducing atmosphere at 1460℃. Combined with an ammonia rapid cooling recovery system, the purity of recovered valuable metals such as zinc and lead reaches over 98.5%. The lead solidification rate of the inert aggregate formed by vortex water quenching of the molten glass is >97.9%, completely eliminating landfill environmental risks and generating 1200 yuan / ton in building material revenue. In particular, through a material-energy intelligent balance control algorithm, the system maintains a stable flue gas temperature of 130±5℃ and NOx emissions <80 mg / Nm³ even with fluctuations in waste calorific value of ±15%, achieving an operational stability of 95.9%. The incineration plant, which processes 200,000 tons of waste annually, can produce an additional 5,000 tons of ammonium sulfate fertilizer (meeting GB / T 535-2020 superior grade), 8,000 tons of glass aggregate, and 150 tons of recycled metal, increasing the overall revenue by 23 million yuan and shortening the investment payback period to 3.8 years. It provides waste incineration plants with an industrial-grade solution that combines near-zero pollutant emissions with positive resource production. Attached Figure Description

[0061] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0062] Figure 1 This is a block diagram of a multi-purpose integrated utilization system for waste incinerator flue gas in Example 1. Detailed Implementation

[0063] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0064] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0065] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0066] Example 1, referring to Figure 1 This is the first embodiment of the present invention. This embodiment provides a multi-purpose comprehensive utilization system for flue gas from a waste incinerator, including a flue gas energy cascade utilization module, a pollutant synergistic removal and resource utilization module, and a fly ash high-temperature melting and solidification module.

[0067] The flue gas energy cascade utilization module is configured to divert the high-temperature flue gas (>850℃) generated by the incinerator to the waste heat boiler for power generation, and the medium- and low-temperature flue gas (180~250℃) to the sludge drying system.

[0068] The pollutant co-removal and resource recovery module is configured to receive flue gas after energy recovery at 120-180℃, and simultaneously remove acidic gases, heavy metals and dioxins in a single reaction tower through a swirl atomization coupled adsorption process, and convert the reaction products into ammonium sulfate crystals;

[0069] The fly ash high-temperature melting and solidification module is configured to mix fly ash captured by a bag filter with a melting aid, and then perform arc melting in a reducing atmosphere at ≥1400℃ to form a glassy inert building material.

[0070] The intelligent diversion device in the flue gas energy cascade utilization module uses a dual-channel pneumatic regulating valve assembly as the core actuator. This valve assembly is cast from high-temperature resistant 310S stainless steel, with a valve plate thickness of 20mm and a 0.5mm thick tungsten carbide wear-resistant layer sprayed on the surface. The valve shaft is equipped with a magnetostrictive displacement sensor to provide real-time feedback on the opening position, achieving a control accuracy of ±0.5°.

[0071] During operation, the valve assembly receives interlock signals from the temperature sensor and the sludge treatment system: when the K-type thermocouple installed at the outlet of the waste heat boiler detects that the flue gas temperature is in the range of 180~250℃, the valve plate angle is dynamically adjusted by the PLC controller, so that the proportion of flue gas entering the sludge drying system is continuously adjustable between 30% and 70%; at the same time, based on the moisture content data fed back by the sludge silo weighing module, the corresponding relationship between the flue gas flow rate and the sludge feeding rate is automatically matched to achieve precise heat energy distribution of 1200~1500m³ of flue gas per ton of wet sludge.

[0072] The sludge drying system uses a multi-stage spiral feeder dryer as its core equipment. Its cylinder is made of double-layer 316L stainless steel plate, with an inner layer plate thickness of 8mm and laser-welded axial finned tube bundles. The fins are 15mm high, 10mm apart, and arranged in a 45° staggered pattern to form a flue gas turbulence channel.

[0073] After being fed into the feed inlet, the wet sludge undergoes three stages under the mechanical propulsion of the variable-pitch screw blades: the 300mm wide pitch in the feeding section forms a 20-30mm thin layer of sludge, increasing the contact area with flue gas; the 150mm narrow pitch in the middle section applies a linear pressure of 0.3MPa to the sludge, disrupting the colloidal structure and releasing bound water; and the 250mm standard pitch in the discharge section ensures uniform discharge of the dried products.

[0074] The dryer shell is equipped with an insulation jacket, through which saturated steam at a pressure of 0.6 MPa and a temperature of 165°C is introduced. The heat loss at the end of the cylinder is compensated by thermal radiation, ensuring that the sludge temperature at the discharge port remains stable above 75°C.

[0075] The flue gas flows laterally across the finned tube bundle at a design velocity of 4 m / s. Under turbulent conditions with a Reynolds number Re > 5000, forced convection heat transfer between the sensible heat of the flue gas and the sludge particles is achieved, with a heat transfer efficiency of 85 W / (m²·K). Ultimately, the sludge moisture content is reduced from 80% to below 12%.

[0076] The variable pitch screw shaft of the multi-stage spiral feeder is made of high-strength duplex steel S31803 integral forging. The main shaft has a diameter of 200mm and a 1.5mm thick Stellite alloy wear-resistant layer is welded on the surface. The thickness of the spiral blades gradually changes from 12mm to 20mm from the feed end to the discharge end. The feed section is set with a 300mm equidistant screw pitch to form a fluffy chamber with a volume of 0.8m³, so that the wet sludge with an initial moisture content of 80% is evenly spread on the bottom of the conveying trough with a thickness of 15~20cm.

[0077] The pitch of the middle section is sharply reduced to 150mm while maintaining a compression zone of 5 times the diameter. The edges of the spiral blades are machined into 45° acute-angle cutting edges. At a speed of 3~5r / min, a linear mechanical pressure of 0.35MPa is applied to the sludge to forcefully crush the cell walls of microorganisms in the sludge and release bound water. The inner wall of this section is fitted with flow-blocking ribs with a height of 10mm. The ribs are arranged in a spiral with a spacing of 50mm to enhance the reverse shearing effect.

[0078] The discharge section has an extended screw pitch of 250mm and is equipped with a conical discharge hood. Under the combined action of mechanical pushing and gravity settling, it forms granular dried products with a particle size of 5~10mm. The moisture content gradient fluctuation does not exceed ±2%, and is finally stably controlled in the range of 12%~15%.

[0079] The dryer shell is wrapped with a double layer of aluminum silicate insulation to form a jacket structure. Saturated steam with a pressure of 0.4MPa and a temperature of 170℃ is introduced into the jacket. The steam inlet is located within 2m of the last section of the cylinder and flows through the jacket in a counter-current manner. The heat loss at the end caused by the temperature decay of the flue gas is compensated by heat conduction, ensuring that the material temperature at the outlet is kept constant at 70±5℃.

[0080] The reaction tower for the co-removal and resource utilization module of pollutants adopts a three-section integrated structure. The tower body is formed by rolling and welding 6mm thick titanium steel composite plate. The contraction angle of the bottom Venturi acceleration section is designed to be 25°, and the throat diameter is reduced to 1 / 3 of the inlet section, which makes the flue gas velocity increase sharply from 8m / s to 28m / s. At the same time, lime slurry is injected at a pressure of 0.3MPa through an annular distributor. The droplet particle size D50=50μm, forming a mixing field with gas-liquid turbulence intensity >0.4 in the throat.

[0081] The central swirling atomization layer is equipped with six radially symmetrical ultrasonic atomization units, each equipped with 12 piezoelectric ceramic nozzles with a frequency of 1.7MHz. Activated carbon-nano titanium dioxide composite adsorbent is sprayed at a dosage of 0.8g / Nm³. The nano titanium dioxide loading in the adsorbent is 15wt%, with a particle size distribution D90≤8μm. The spray cone angle is 60°, covering more than 95% of the tower cross-section. Swirling adsorption clouds are formed during the flue gas rise, with a residence time ≥4s.

[0082] Three layers of gradient sieve plates with varying apertures are arranged at the top. The bottom sieve plate has an opening rate of 40% and an aperture of 3mm, the middle sieve plate has an opening rate of 35% and an aperture of 2mm, and the top sieve plate has an opening rate of 30% and an aperture of 1mm. The sieve plates are spaced 300mm apart and arranged in a staggered 30° rotation. A 10% concentration of ammonium sulfate mother liquor is evenly distributed above the sieve plates through an overflow trough. The liquid film thickness is 2~3mm, which allows the flue gas to be divided into microbubble groups by the liquid film when it passes through the sieve holes at a flow rate of 7m / s. The gas-liquid contact specific surface area reaches 1200m² / m³.

[0083] The crystallization tank at the bottom of the tower is equipped with a hyperboloid guide tube. A seed generator with an adjustable speed of 10~30 r / min is installed at the bottom of the guide tube. The supersaturation of the slurry is monitored in real time by an online conductivity meter and the amount of ammonium sulfate mother liquor sprayed is adjusted accordingly to maintain the supersaturation coefficient of the crystallization zone stable between 1.08 and 1.12. Finally, cubic ammonium sulfate crystals with a particle size of 1.2±0.3 mm are precipitated on the tank wall.

[0084] The adsorbent regeneration unit of the pollutant synergistic removal and resource utilization module includes a microwave desorption system and a pneumatic circulation system. The microwave desorption chamber adopts a rectangular multimode resonant cavity design with a cavity size of 1200×800×600mm. The inner wall is lined with a 2mm thick sintered alumina ceramic layer. The top is arrayed with 12 sets of magnetron emission sources, each with a power of 1.2kW and a working frequency of 2450±50MHz. A high-temperature resistant silicon carbide conveyor belt is installed at the bottom of the cavity. The conveyor belt running speed is adjustable from 0.5 to 2m / min. The saturated adsorbent forms a uniform material layer with a thickness of 30mm on the conveyor belt.

[0085] The desorption process employs a three-stage temperature control strategy: the feeding stage starts at 40% power to preheat the material to 80~100℃; the middle stage starts at 100% power to raise the temperature to 450±10℃ within 3 minutes to achieve desorption of organic matter; the discharge stage reduces the power to 60% and maintains 300℃ to prevent the adsorbent from becoming embrittled due to sudden cooling; the gaseous pollutants generated by desorption are introduced into the bypass combustion chamber through the negative pressure gas collection hood, where they stay in the 1100℃ high-temperature zone for 2.5 seconds to completely decompose dioxins;

[0086] The regenerated adsorbent is cooled to below 80°C by a spiral cooler and then enters the Venturi injector of the pneumatic circulation system. The flow velocity at the throat of the injector reaches 25 m / s. The adsorbent particles are transported to the storage silo using 0.6 MPa compressed air. A fluidized bed homogenizer is installed at the bottom of the storage silo, and dry air with a flow rate of 50 m³ / h is introduced to maintain the loose state of the adsorbent.

[0087] The circulation system is equipped with an online activity detector, which monitors the decay rate of the adsorbent's specific surface area in real time using laser scattering. When the detected value is lower than 80% of the initial value, the replenishment program is automatically started to ensure that the adsorbent activity of the system is maintained above 95%, and the energy consumption of the entire regeneration process is ≤0.8kWh / kg adsorbent.

[0088] The pretreatment unit of the fly ash high-temperature melting and solidification module adopts a two-stage mixing process. In the first stage, fly ash collected by electrostatic precipitator and melting aid, SiO2:Al2O3:CaO=52:30:18, are added to a conical mixer at a mass ratio of 1:0.28. The mixture is dry-mixed for 5 minutes at a speed of 15 r / min to form a basic mixture. In the second stage, sodium lignosulfonate solution accounting for 12% of the total amount is added as a binder. The mixture is wet-mixed for 8 minutes at a speed of 45 r / min in a twin-shaft paddle mixer. Finally, it is formed into a Φ22×35mm cylindrical blank by a hydraulic pressing machine. The density of the blank is controlled at 1.8±0.1g / cm³ and the compressive strength is ≥5MPa.

[0089] The melting unit adopts a vertical DC electric arc furnace, with the furnace chamber lined with corundum refractory material, Al2O3≥95%. The furnace body is divided into upper and lower zones: the lower zone is a reduction melting pool, where three Φ300mm graphite electrodes are inserted into the melting pool at 120°, and the electrode current density is maintained at 85A / cm². A mixture of natural gas and oxygen in a volume ratio of 1:0.6 is introduced to stabilize the melting pool temperature at 1460±20℃ and the CO concentration at 12 vol%. The fly ash billet stays in this zone for 25 minutes to achieve the reduction and volatilization of heavy metals.

[0090] The upper zone is a rapid cooling and recovery zone. 24 sets of ammonia water injectors are arranged circumferentially on the side wall of the furnace top. The injection pressure is 0.4MPa and the atomization angle is 60°. 10% concentration ammonia water is injected into the 850-900℃ flue gas zone at a flow rate of 120L / min, so that the volatilized lead, cadmium and zinc chlorides are converted into metal ammonium salt particles. A quencher is installed at the top of this zone. Liquid nitrogen at -20℃ is introduced to cool the flue gas to below 600℃ within 0.3 seconds to inhibit the resynthesis of dioxins.

[0091] The molten glass is discharged through the overflow port into the water quenching tank, where hot water at 80°C is circulated and impacted with the molten flow at a flow rate of 10 m / s. The water quenching ratio is controlled at 1:1.2, producing glassy aggregate with a particle size of 4~9 mm. The total content of SiO2+Al2O3+CaO is >85%, and the leaching concentrations of heavy metals Pb and Cd are less than 0.05 mg / L and 0.01 mg / L, respectively.

[0092] Volatile heavy metal ammonium salts are collected by a bag filter and then enter a dilute sulfuric acid dissolution tank. The solution is then electrowinning to recover zinc ingots and lead-cadmium alloys with a purity of 99.5%.

[0093] The molten product processing of the fly ash high-temperature melting and solidification module includes two paths: glass resource utilization and heavy metal directional recycling. When the molten glass is processed in the water quenching tank, a stepped cooling process is adopted: the high-temperature glass flow first enters the first-stage quenching chamber and is mixed with 80°C circulating hot water at a volume ratio of 10:1. The water flow velocity of 12m / s impacts the glass flow, causing it to initially break up. Then it falls into the second-stage vortex chamber, where three sets of tangential water inlet pipes are set up to form a swirling flow field with a Reynolds number Re > 12000. Under the action of centrifugal force, the glass is broken into 4~8mm particles.

[0094] After quenching, the glass particles are separated by a dewatering screen and then subjected to two-stage countercurrent rinsing to remove surface alkali metal salts. The pH value of the rinsing water is controlled at 6.5~7.0, and finally an inert aggregate with SiO2+Al2O3 content >75% is obtained. The TCLP leaching concentrations of lead, chromium and nickel are less than 0.03mg / L, 0.02mg / L and 0.05mg / L, respectively.

[0095] The heavy metal recovery system adopts a multi-stage integrated design: flue gas containing heavy metal ammonium salts is quenched and then enters a pulse bag filter. The filter bag surface is covered with a PTFE membrane with a pore size of 0.5μm, and the collection efficiency is >99.9%. The collected metal ammonium salt dust is introduced into a dissolution tank. A 15% dilute sulfuric acid solution is added to the tank and the liquid-solid ratio is maintained at 5:1. The tank is stirred at 50℃ for 30 minutes to fully dissolve zinc ammonium salt and lead ammonium salt.

[0096] After insoluble substances are removed by a precision filter, the solution enters a four-chamber electrowinning cell. The anode is a titanium-based iridium-tantalum coated plate, and the cathodes are stainless steel plates and aluminum plates, respectively. Selective electrowinning is carried out under the conditions of current density of 300 A / m² in the zinc region and 150 A / m² in the lead-cadmium region.

[0097] Electrowinning product processing: The zinc cathode is stripped every 8 hours and then vacuum-cast to obtain zinc ingots with a purity of 99.8%. The lead-cadmium deposits are dissolved in dilute nitric acid and then separated by solvent extraction. The organic phase is selected from the 20% tributyl phosphate-kerosene system, and the final product is a lead-cadmium alloy with Pb:Cd=85:15 and 99.5% pure cadmium.

[0098] The wastewater from the entire process is neutralized and precipitated before being reused in the water quenching system, achieving a heavy metal recovery rate of >92% for zinc, >95% for lead, and >88% for cadmium, with no secondary waste discharge.

[0099] The intelligent control system constructs a three-layer monitoring-execution architecture. K-type armored thermocouples and anti-clogging Pitot tubes are installed at the waste heat boiler outlet, sludge dryer inlet, and pollutant removal tower of the flue gas energy cascade utilization module to collect temperature and pressure data in real time. Current transformers and infrared thermometers are integrated on the electrode columns of the fly ash melting furnace to continuously monitor the melting state.

[0100] The core control cabinet adopts a redundant PLC system with a main processor processing cycle of ≤10ms and a built-in multivariable coupled control algorithm: when the flue gas calorific value fluctuation is detected to exceed the set threshold, the material-energy balance compensation mechanism is automatically activated. First, the opening of the flue gas diversion valve is adjusted at a rate of 10% / s to maintain the sludge dryer inlet temperature at 185±5℃. At the same time, the activated carbon injection amount is proportionally corrected, with a 0.05g / Nm³ change in injection amount corresponding to every 100kcal / Nm³ change in calorific value. The power of the melting furnace is dynamically adjusted based on the online analysis results of the fly ash heavy metal content. For every 100mg / kg increase in lead content, the electrode current is increased by 2%.

[0101] Hard interlock protection is set up for sudden system failures: when the pressure difference of the bag filter is >1500Pa, the adsorbent injection is immediately cut off and the bypass flue is started; when the temperature of the melting furnace is below 1400℃ for 30 seconds, auxiliary fuel is automatically injected, and the natural gas flow rate is adjustable from 0 to 50m³ / min; when the oxygen content of the flue gas exceeds 8%, the feed valve of the sludge dryer is closed in conjunction with the system.

[0102] All monitoring data are transmitted to the central monitoring station via an industrial fiber optic ring network. The station is equipped with a 3D visualization platform that renders the flue gas flow trajectory and temperature field distribution in real time. The operation interface is embedded with a fault diagnosis expert database, and an emergency response plan is automatically popped up for abnormal data. The system response delay is ≤200ms.

[0103] The control program is equipped with a self-learning function: it automatically generates an operation optimization report every 1000 hours of operation, and corrects the key parameter settings based on historical data, so that the system can maintain the pollutant removal efficiency fluctuation range of <±1.5% even under seasonal changes in waste composition.

[0104] The optimized heat recovery method achieves deep energy utilization through a three-stage heat exchange of steam, flue gas, and air. The water vapor generated by the sludge drying system, with a pressure of 0.15 MPa and a temperature of 75~80℃, enters the ejector mixer after the droplets are removed by the demister. The diameter of the mixer throat is designed to be 1 / 4 of the inlet pipe, and the steam flow is ejected at a flow rate of 20 m / s, so that it is fully mixed with the flue gas at 160~170℃ in the front section of the SCR reactor in the Venturi section.

[0105] The temperature of the mixed flue gas is monitored in real time by a thermocouple array. When the temperature is below 190℃, the steam injection valve is automatically activated. Through PID regulation with a proportional band of 80% and an integral time of 60s, the flue gas temperature is stabilized at 195±3℃, which is the optimal activity window for the denitrification catalyst. This temperature control accuracy is more than 50% higher than that of conventional flue gas heat exchangers. The flue gas at 230-250℃ after the SCR reaction enters the plate heat exchanger to recover waste heat. The heat exchange plates are made of 0.5mm thick 254SMO super stainless steel laser-welded and formed with a plate corrugation angle of 60°, forming cross-flow channels that make the flue gas velocity 8m / s and the air velocity 12m / s, with a heat exchange area density of 250m² / m³.

[0106] The air side adopts a two-stage preheating design: cold air is first preheated to 110°C in the low-temperature section of the heat exchanger, and then heated to 150°C in the high-temperature section. The preheated air is delivered in two routes: 80% of the flow from the main route is connected to the primary air system of the incinerator, and 20% of the flow from the branch route is sent to the combustion air duct of the fly ash melting furnace.

[0107] The heat exchanger condensate collection system is equipped with an online pH adjustment unit. When the pH of the condensate is detected to be less than 5.5, 10% NaOH solution is automatically injected to neutralize it and maintain the pH value at 6.8~7.2, which meets the closed-loop recycling standard. The entire heat recovery system increases the total thermal efficiency to 86.5%, which is 12 percentage points higher than that of conventional incineration plants.

[0108] The optimization of the ammonium sulfate crystallization process is achieved through precise control of crystallization kinetics. The conical crystallization tank at the bottom of the reaction tower is designed with a volume of 8m³. The tank wall adopts a double-layer structure: the inner liner is a 4mm thick Hastelloy C276 plate, and the outer jacket is filled with 25℃ circulating cooling water to maintain the temperature gradient of the tank wall. A hyperboloid guide tube is vertically installed at the center of the tank. The guide tube has an upper diameter of 800mm, a lower diameter of 500mm, and a height of 1200mm. The tube wall has 120 spirally distributed Φ10mm guide holes with an inclination angle of 45°.

[0109] A variable frequency seed generator is installed at the bottom of the guide tube. The generator disc has a diameter of 400 mm and 48 wedge-shaped grooves with a depth of 5 mm evenly distributed on the edge. It continuously releases ammonium sulfate seed crystals with a particle size of 0.2~0.3 mm at a rotation speed of 20 r / min. The seed crystal addition amount is 0.8 wt% of the crystallization mother liquor flow rate.

[0110] The supersaturation control adopts a dual-parameter feedback mechanism of conductivity and density: an online conductivity meter and a vibrating density meter are installed at the outlet of the guide tube to monitor the changes in the physical properties of the slurry in real time. When the conductivity exceeds 180 mS / cm and the density is >1150 kg / m³, the PLC system automatically increases the opening of the ammonium sulfate mother liquor feed valve at a rate of 5% / s to stabilize the supersaturation in the metastable range of 1.10 ± 0.02.

[0111] The crystallized product is fed into a horizontal pusher centrifuge via an overflow weir. The centrifuge drum diameter is 1000 mm, the differential speed is 15 r / min, and it is operated under a separation factor of 800. The water content of the separated ammonium sulfate crystals is ≤0.5%. After being treated in a fluidized bed dryer with hot air at 80℃ for 10 minutes, a cubic crystal product of 1.0~1.5 mm is obtained.

[0112] The centrifuged mother liquor is introduced into a neutralization and adjustment tank, which is equipped with a pH electrode and an ultrasonic mixer. When the pH is <6.3, a metering pump is started to inject 10% ammonia water. When the pH is >7.2, 30% dilute sulfuric acid is added. Finally, the pH of the mother liquor is precisely controlled at 6.8±0.1. After the adjusted mother liquor is filtered to remove suspended solids, it is returned to the desulfurization system for recycling. The mother liquor reuse rate is >95% and there is no risk of crystallization salt accumulation.

[0113] Example 2 is the second embodiment of the present invention. The working process of a multi-purpose comprehensive utilization system for waste incinerator flue gas in this embodiment is as follows:

[0114] The waste incinerator produces high-temperature flue gas exceeding 850℃, which first enters the waste heat boiler power generation system. After the flue gas temperature drops to 400℃, it is divided into two paths: the main path enters the steam superheater for further energy recovery, while the branch path uses an intelligent diversion device to guide the medium-low temperature flue gas (180-250℃) into the sludge drying unit. The drying system uses a variable-pitch screw dryer. The wet sludge (80% moisture content) is loosely spread in the feeding section, undergoes mechanical compression to break up the colloidal structure in the middle section, and forms particles with a moisture content of 12% in the discharge section. The entire process utilizes the sensible heat of the flue gas to complete the moisture evaporation. The 120-180℃ flue gas after energy recovery enters a three-stage reaction tower. In the bottom Venturi section, it flows at a velocity of 28 m / s with lime. SO2 is removed by turbulent mixing of the slurry. Dioxins and heavy metals are captured by activated carbon-nano titanium dioxide composite adsorbent sprayed in the central swirl atomization layer. Deep desulfurization and crystallization are induced by ammonium sulfate mother liquor film in the top sieve plate area. The purified flue gas is discharged after passing through bag filter dust collector. The captured fly ash is mixed with melting aid at a ratio of 1:0.28 and pressed into a compact. It is then melted in a reducing electric arc furnace at 1460℃. The molten glass is water-quenched to form inert aggregate. Volatile heavy metals are converted into metallic ammonium salts by rapid cooling with ammonia gas at 850℃. The entire system is dynamically controlled by an intelligent control system, which adjusts the opening of the diversion valve, the amount of adsorbent sprayed, and the melting power based on real-time monitoring data to achieve a closed-loop balance of matter and energy.

[0115] 1. Implementation of cascade utilization of flue gas energy

[0116] A K-type thermocouple is installed at the outlet of the waste heat boiler to monitor the flue gas temperature. When the temperature reaches 230±5℃, the PLC controls the dual-channel pneumatic regulating valve to introduce 45% of the flue gas (approximately 65000 Nm³ / h) into the sludge drying system.

[0117] Operating parameters of the multi-stage spiral dryer: feed section with a screw pitch of 300mm and a conveying speed of 1.5m / min; middle section with a screw pitch of 150mm and a linear pressure of 0.35MPa; discharge section with a screw pitch of 250mm and discharges particles with a diameter of 8mm; the dryer jacket is supplied with 0.6MPa, 170℃ steam to compensate for heat loss.

[0118] Actual test data: The treatment capacity of municipal sludge with a moisture content of 78% is 15t / h, the flue gas consumption is 62000Nm³ / h, the output moisture content is stable at 13.5%, and the flue gas temperature drops to 135℃.

[0119] 2. Implementation of Co-processing Removal of Pollutants

[0120] Reactor tower operating parameters: Venturi throat flow velocity 28 m / s, lime slurry concentration 15%, flow rate 8 m³ / h; swirl atomization layer sprayed composite adsorbent (activated carbon loaded with 15% nano TiO2) 0.75 g / Nm³.

[0121] Ammonium sulfate crystallization control: The supersaturation of the crystallization tank at the bottom of the tower is maintained at 1.10. 0.25 mm seed crystals are added at a rate of 20 kg / h by the seed generator to produce 1.2 mm cubic crystals;

[0122] Adsorbent regeneration: Saturated adsorbent was introduced into the microwave chamber at a flux of 500 kg / h and irradiated at 950 W and 2.45 GHz for 4 minutes. After regeneration, the specific surface area remained at 92% of the initial value.

[0123] Emission indicators: According to third-party testing, SO2=18mg / Nm³, NOx=63mg / Nm³, and dioxin=0.028ng-TEQ / Nm³.

[0124] 3. Implementation of fly ash melting and solidification

[0125] Fly ash pretreatment: Electrostatic precipitator ash and additives (SiO2:Al2O3:CaO=52:30:18) are mixed at a ratio of 1:0.28 and pressed into a green body with a density of 1.82 g / cm³.

[0126] Electric arc furnace operation: graphite electrode current density 85A / cm², natural gas-oxygen mixture (V / V=1:0.6) is introduced, and the molten pool temperature is 1465±15℃;

[0127] Heavy metal recovery: Ammonia water injection rate of 110L / min, after rapid cooling, the bag filter collects ammonium salt dust containing 35% zinc and 18% lead, and produces 99.6% zinc ingots through electrowinning;

[0128] Vitreous properties: water-quenched aggregate particle size 5.5±1.2mm, TCLP test Pb leaching concentration 0.026mg / L (national standard limit 5mg / L).

[0129] 4. System integration and control implementation

[0130] Intelligent control case: When the calorific value of waste suddenly drops from 6500kJ / kg to 5500kJ / kg, the system automatically executes:

[0131] Adjust the flow divider valve opening from 50% to 65% to maintain the drying temperature;

[0132] The adsorbent injection rate was increased from 0.70 g / Nm³ to 0.82 g / Nm³;

[0133] An 8% increase in furnace power compensates for the increased fly ash content;

[0134] Heat recovery effect: The SCR inlet temperature is stable at 198℃ (set value 195℃), the plate heat exchanger preheats the combustion air to 152℃, and the condensate recovery rate is 100%.

[0135] Verification of the technical effects of the example:

[0136] In a test of a waste incineration plant that processes 600 tons of waste per day, operating continuously for 720 hours:

[0137] Energy performance indicators: Overall system thermal efficiency 86.2%, power generation per ton of waste reaches 583 kWh (compared to 498 kWh with conventional technology);

[0138] Economic benefits: By-product output includes 1.8 tons of ammonium sulfate per day (valued at RMB 2,200 per ton), 2.9 tons of glass aggregate per day (valued at RMB 1,200 per ton), and 0.12 tons of zinc ingots per day (valued at RMB 18,500 per ton).

[0139] Environmental performance: Compared with the national standard GB18485-2014, dioxin emissions are only 11% of the limit, and heavy metal emissions are below the detection limit;

[0140] Operational stability: Under conditions where the calorific value of waste fluctuates by 12.7%, the system's automatic adjustment response time is ≤3 seconds, and the deviation rate of key parameters is <1.8%;

[0141] This embodiment demonstrates the engineering feasibility of the technical solution through innovation in physical equipment and optimization of process parameters. Its material-energy synergistic conversion efficiency, pollutant control level, and resource output value all reach international leading standards.

[0142] This embodiment also provides a computer device applicable to a multi-purpose integrated utilization system for waste incinerator flue gas, comprising: a memory and a processor; the memory is used to store computer-executable instructions, and the processor is used to execute the computer-executable instructions to realize a multi-purpose integrated utilization system for waste incinerator flue gas as proposed in the above embodiment.

[0143] The computer device can be a terminal, comprising a processor, memory, communication interface, display screen, and input devices connected via a system bus. The processor provides computing and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs stored in the non-volatile storage media. The communication interface is used for wired or wireless communication with external terminals; wireless communication can be achieved through Wi-Fi, carrier networks, NFC (Near Field Communication), or other technologies. The display screen can be an LCD screen or an e-ink screen. The input devices can be a touch layer covering the display screen, buttons, a trackball, or a touchpad on the computer device's casing, or an external keyboard, touchpad, or mouse.

[0144] This embodiment also provides a storage medium storing a computer program, which, when executed by a processor, implements a multi-purpose integrated utilization system for waste incinerator flue gas as proposed in the above embodiments. The storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as Static Random Access Memory (SRAM), Electrically Erasable Programmable Read-Only Memory (EEPROM), Erasable Programmable Read Only Memory (EPROM), Programmable Red-Only Memory (PROM), Read-Only Memory (ROM), magnetic storage, flash memory, magnetic disk, or optical disk.

[0145] In summary, this invention fundamentally overcomes the technical bottlenecks of traditional waste incineration flue gas treatment by constructing a three-dimensional coupled system of "energy cascade utilization - pollutant synergistic conversion - high-value utilization of fly ash". In terms of energy recovery, the innovative intelligent diversion device combined with a multi-stage spiral dryer directly utilizes the sensible heat of the 180-250℃ medium-low temperature flue gas for sludge drying. Compared to conventional heat exchanger recovery methods, the heat transfer efficiency is increased from 60% to 92%. Combined with the optimized process of steam waste heat recovery and SCR denitrification, the overall system thermal efficiency exceeds 86.5%, translating to an increase of 85 kWh of power generation per ton of waste. In the field of pollutant control, the unique three-stage reaction tower integrates cyclone atomization adsorption and sieve plate membrane reaction technology, simultaneously completing desulfurization and denitrification (efficiency > 98%), dioxin decomposition (decomposition rate > 97%), and... Heavy metal capture (removal rate >95%) reduces equipment footprint by 40% while activated carbon consumption drops to below 80 mg / Nm³. Furthermore, microwave regeneration technology enables up to 20 cycles of adsorption, saving over 3 million yuan annually in adsorption costs. Addressing the challenge of fly ash disposal, the fly ash pressing and melting process achieves efficient volatilization and separation of heavy metals in a reducing atmosphere at 1460℃. Combined with an ammonia rapid cooling recovery system, the purity of recovered valuable metals such as zinc and lead reaches over 98.5%. The lead solidification rate of the inert aggregate formed by vortex water quenching of the molten glass is >97.9%, completely eliminating landfill environmental risks and generating 1200 yuan / ton in building material revenue. In particular, through a material-energy intelligent balance control algorithm, the system maintains a stable flue gas temperature of 130±5℃ and NOx emissions <80 mg / Nm³ even with fluctuations in waste calorific value of ±15%, achieving an operational stability of 95.9%. The incineration plant, which processes 200,000 tons of waste annually, can produce an additional 5,000 tons of ammonium sulfate fertilizer (meeting GB / T 535-2020 superior grade), 8,000 tons of glass aggregate, and 150 tons of recycled metal, increasing the overall revenue by 23 million yuan and shortening the investment payback period to 3.8 years. It provides waste incineration plants with an industrial-grade solution that combines near-zero pollutant emissions with positive resource production.

[0146] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A multi-purpose integrated utilization system for flue gas from a waste incinerator, characterized in that, include: Flue gas energy cascade utilization module, pollutant synergistic removal and resource utilization module, fly ash high-temperature melting and solidification module; The flue gas energy cascade utilization module is configured to divert the high-temperature flue gas (>850°C) generated by the incinerator to the waste heat boiler for power generation, and the medium- and low-temperature flue gas (180~250°C) to the sludge drying system. The pollutant co-removal and resource utilization module is configured to receive flue gas after energy recovery at 120-180°C, and simultaneously remove acidic gases, heavy metals and dioxins in a single reaction tower through a swirl atomization coupled adsorption process, and convert the reaction products into ammonium sulfate crystals. The fly ash high-temperature melting and solidification module is configured to mix the fly ash captured by the bag filter with a melting aid, and then perform arc melting in a reducing atmosphere at ≥1400℃ to form a glassy inert building material.

2. The multi-purpose comprehensive utilization system for waste incinerator flue gas as described in claim 1, characterized in that: The intelligent diversion device in the flue gas energy cascade utilization module uses a dual-channel pneumatic regulating valve assembly as the core actuator. This valve assembly is cast from high-temperature resistant 310S stainless steel, with a valve plate thickness of 20mm and a 0.5mm thick tungsten carbide wear-resistant layer sprayed on the surface. The valve shaft is equipped with a magnetostrictive displacement sensor to provide real-time feedback on the opening position, achieving a control accuracy of ±0.5°. During operation, the valve assembly receives interlock signals from the temperature sensor and the sludge treatment system: when the K-type thermocouple installed at the outlet of the waste heat boiler detects that the flue gas temperature is in the range of 180~250℃, the valve plate angle is dynamically adjusted by the PLC controller, so that the proportion of flue gas entering the sludge drying system is continuously adjustable between 30% and 70%; at the same time, based on the moisture content data fed back by the sludge silo weighing module, the corresponding relationship between the flue gas flow rate and the sludge feeding rate is automatically matched to achieve precise heat energy distribution of 1200~1500m³ of flue gas per ton of wet sludge. The sludge drying system uses a multi-stage spiral feeder dryer as its core equipment. Its cylinder is made of double-layer 316L stainless steel plate, with an inner layer plate thickness of 8mm and laser-welded axial finned tube bundles. The fins are 15mm high, 10mm apart, and arranged in a 45° staggered pattern to form a flue gas turbulence channel. After being fed into the feed inlet, the wet sludge undergoes three stages under the mechanical propulsion of the variable-pitch screw blades: the 300mm wide pitch in the feeding section forms a 20-30mm thin layer of sludge, increasing the contact area with flue gas; the 150mm narrow pitch in the middle section applies a linear pressure of 0.3MPa to the sludge, disrupting the colloidal structure and releasing bound water; and the 250mm standard pitch in the discharge section ensures uniform discharge of the dried products. The dryer shell is equipped with an insulation jacket, through which saturated steam at a pressure of 0.6 MPa and a temperature of 165°C is introduced. The heat loss at the end of the cylinder is compensated by thermal radiation, ensuring that the sludge temperature at the discharge port remains stable above 75°C. The flue gas flows laterally across the finned tube bundle at a design velocity of 4 m / s. Under turbulent conditions with a Reynolds number Re > 5000, forced convection heat transfer between the sensible heat of the flue gas and the sludge particles is achieved, with a heat transfer efficiency of 85 W / (m²·K). Ultimately, the sludge moisture content is reduced from 80% to below 12%.

3. The multi-purpose comprehensive utilization system for waste incinerator flue gas as described in claim 2, characterized in that: The variable pitch screw shaft of the multi-stage spiral feeder is made of high-strength duplex steel S31803 integral forging. The main shaft diameter is 200mm and the surface is overlaid with a 1.5mm thick Stellite alloy wear-resistant layer. The thickness of the spiral blades gradually changes from 12mm to 20mm from the feed end to the discharge end. The feed section is set with a 300mm equidistant screw pitch to form a fluffy chamber with a volume of 0.8m³, so that the wet sludge with an initial moisture content of 80% is evenly spread on the bottom of the conveying trough with a thickness of 15~20cm. The pitch of the middle section is sharply reduced to 150mm while maintaining a compression zone of 5 times the diameter. The edges of the spiral blades are machined into 45° acute-angle cutting edges. At a speed of 3~5r / min, a linear mechanical pressure of 0.35MPa is applied to the sludge to forcefully crush the cell walls of microorganisms in the sludge and release bound water. The inner wall of this section is fitted with flow-blocking ribs with a height of 10mm. The ribs are arranged in a spiral with a spacing of 50mm to enhance the reverse shearing effect. The discharge section has an extended screw pitch of 250mm and is equipped with a conical discharge hood. Under the combined action of mechanical pushing and gravity settling, it forms granular dried products with a particle size of 5~10mm. The moisture content gradient fluctuation does not exceed ±2%, and is finally stably controlled in the range of 12%~15%. The dryer shell is wrapped with a double layer of aluminum silicate insulation to form a jacket structure. Saturated steam with a pressure of 0.4MPa and a temperature of 170℃ is introduced into the jacket. The steam inlet is located within 2m of the last section of the cylinder and flows through the jacket in a counter-current manner. The heat loss at the end caused by the temperature decay of the flue gas is compensated by heat conduction, ensuring that the material temperature at the outlet is kept constant at 70±5℃.

4. The multi-purpose comprehensive utilization system for waste incinerator flue gas as described in claim 3, characterized in that: The reaction tower of the pollutant synergistic removal and resource utilization module adopts a three-section integrated structure. The tower body is formed by rolling and welding 6mm thick titanium steel composite plate. The contraction angle of the bottom Venturi acceleration section is designed to be 25°, and the throat diameter is reduced to 1 / 3 of the inlet section, which makes the flue gas velocity increase sharply from 8m / s to 28m / s. At the same time, lime slurry is injected at a pressure of 0.3MPa through an annular distributor. The droplet particle size D50=50μm, forming a mixing field with gas-liquid turbulence intensity >0.4 in the throat. The central swirling atomization layer is equipped with six radially symmetrical ultrasonic atomization units, each equipped with 12 piezoelectric ceramic nozzles with a frequency of 1.7MHz. Activated carbon-nano titanium dioxide composite adsorbent is sprayed at a dosage of 0.8g / Nm³. The nano titanium dioxide loading in the adsorbent is 15wt%, with a particle size distribution D90≤8μm. The spray cone angle is 60°, covering more than 95% of the tower cross-section. Swirling adsorption clouds are formed during the flue gas rise, with a residence time ≥4s. Three layers of gradient sieve plates with varying apertures are arranged at the top. The bottom sieve plate has an opening rate of 40% and an aperture of 3mm, the middle sieve plate has an opening rate of 35% and an aperture of 2mm, and the top sieve plate has an opening rate of 30% and an aperture of 1mm. The sieve plates are spaced 300mm apart and arranged in a staggered 30° rotation. A 10% concentration of ammonium sulfate mother liquor is evenly distributed above the sieve plates through an overflow trough. The liquid film thickness is 2~3mm, which allows the flue gas to be divided into microbubble groups by the liquid film when it passes through the sieve holes at a flow rate of 7m / s. The gas-liquid contact specific surface area reaches 1200m² / m³. The crystallization tank at the bottom of the tower is equipped with a hyperboloid guide tube. A seed generator with an adjustable speed of 10~30 r / min is installed at the bottom of the guide tube. The supersaturation of the slurry is monitored in real time by an online conductivity meter and the amount of ammonium sulfate mother liquor sprayed is adjusted accordingly to maintain the supersaturation coefficient of the crystallization zone stable between 1.08 and 1.

12. Finally, cubic ammonium sulfate crystals with a particle size of 1.2±0.3 mm are precipitated on the tank wall.

5. A multi-purpose integrated utilization system for waste incinerator flue gas as described in claim 4, characterized in that: The adsorbent regeneration unit of the pollutant synergistic removal and resource utilization module includes a microwave desorption system and a pneumatic circulation system. The microwave desorption chamber adopts a rectangular multimode resonant cavity design with a cavity size of 1200×800×600mm. The inner wall is covered with a 2mm thick sintered alumina ceramic layer. The top is arrayed with 12 sets of magnetron emission sources, each with a power of 1.2kW and a working frequency of 2450±50MHz. A high-temperature resistant silicon carbide conveyor belt is installed at the bottom of the cavity. The conveyor belt running speed is adjustable from 0.5 to 2m / min. The saturated adsorbent forms a uniform material layer with a thickness of 30mm on the conveyor belt. The desorption process employs a three-stage temperature control strategy: the feeding stage starts at 40% power to preheat the material to 80~100℃; the middle stage starts at 100% power to raise the temperature to 450±10℃ within 3 minutes to achieve desorption of organic matter; the discharge stage reduces the power to 60% and maintains 300℃ to prevent the adsorbent from becoming embrittled due to sudden cooling; the gaseous pollutants generated by desorption are introduced into the bypass combustion chamber through the negative pressure gas collection hood, where they stay in the 1100℃ high-temperature zone for 2.5 seconds to completely decompose dioxins; The regenerated adsorbent is cooled to below 80°C by a spiral cooler and then enters the Venturi injector of the pneumatic circulation system. The flow velocity at the throat of the injector reaches 25 m / s. The adsorbent particles are transported to the storage silo using 0.6 MPa compressed air. A fluidized bed homogenizer is installed at the bottom of the storage silo, and dry air with a flow rate of 50 m³ / h is introduced to maintain the loose state of the adsorbent. The circulation system is equipped with an online activity detector, which monitors the decay rate of the adsorbent's specific surface area in real time using laser scattering. When the detected value is lower than 80% of the initial value, the replenishment program is automatically started to ensure that the adsorbent activity of the system is maintained above 95%, and the energy consumption of the entire regeneration process is ≤0.8kWh / kg adsorbent.

6. The multi-purpose comprehensive utilization system for waste incinerator flue gas as described in claim 5, characterized in that: The pretreatment unit of the high-temperature melting and solidification module for fly ash adopts a two-stage mixing process. In the first stage, fly ash collected by the electrostatic precipitator and melting aid, SiO2:Al2O3:CaO=52:30:18, are added to a conical mixer at a mass ratio of 1:0.

28. The mixture is dry-mixed for 5 minutes at a speed of 15 r / min to form a basic mixture. In the second stage, sodium lignosulfonate solution, accounting for 12% of the total amount, is added as a binder. The mixture is wet-mixed for 8 minutes at a speed of 45 r / min in a twin-shaft paddle mixer. Finally, it is formed into a cylindrical blank with a diameter of Φ22×35mm by a hydraulic pressing machine. The density of the blank is controlled at 1.8±0.1g / cm³ and the compressive strength is ≥5MPa. The melting unit adopts a vertical DC electric arc furnace, with the furnace chamber lined with corundum refractory material, Al2O3≥95%. The furnace body is divided into upper and lower zones: the lower zone is a reduction melting pool, where three Φ300mm graphite electrodes are inserted into the melting pool at 120°, and the electrode current density is maintained at 85A / cm². A mixture of natural gas and oxygen in a volume ratio of 1:0.6 is introduced to stabilize the melting pool temperature at 1460±20℃ and the CO concentration at 12 vol%. The fly ash billet stays in this zone for 25 minutes to achieve the reduction and volatilization of heavy metals. The upper zone is a rapid cooling and recovery zone. 24 sets of ammonia water injectors are arranged circumferentially on the side wall of the furnace top. The injection pressure is 0.4MPa and the atomization angle is 60°. 10% concentration ammonia water is injected into the 850-900℃ flue gas zone at a flow rate of 120L / min, so that the volatilized lead, cadmium and zinc chlorides are converted into metal ammonium salt particles. A quencher is installed at the top of this zone. Liquid nitrogen at -20℃ is introduced to cool the flue gas to below 600℃ within 0.3 seconds to inhibit the resynthesis of dioxins. The molten glass is discharged through the overflow port into the water quenching tank, where hot water at 80°C is circulated and impacted with the molten flow at a flow rate of 10 m / s. The water quenching ratio is controlled at 1:1.2, producing glassy aggregate with a particle size of 4~9 mm. The total content of SiO2+Al2O3+CaO is >85%, and the leaching concentrations of heavy metals Pb and Cd are less than 0.05 mg / L and 0.01 mg / L, respectively. Volatile heavy metal ammonium salts are collected by a bag filter and then enter a dilute sulfuric acid dissolution tank. The solution is then electrowinning to recover zinc ingots and lead-cadmium alloys with a purity of 99.5%.

7. A multi-purpose integrated utilization system for waste incinerator flue gas as described in claim 6, characterized in that... It lies in: The molten product processing of the fly ash high-temperature melting and solidification module includes a dual path of glass resource utilization and heavy metal directional recycling. When the molten glass is processed in the water quenching tank, a stepped cooling process is adopted: the high-temperature glass flow first enters the first-stage quenching chamber and is mixed with 80°C circulating hot water at a volume ratio of 10:

1. The water flow velocity of 12m / s impacts the glass flow, causing it to initially break up. Then it falls into the second-stage vortex chamber, where three sets of tangential water inlet pipes are set up to form a swirling flow field with a Reynolds number Re > 12000. Under the action of centrifugal force, the glass is broken into 4~8mm particles. After quenching, the glass particles are separated by a dewatering screen and then subjected to two-stage countercurrent rinsing to remove surface alkali metal salts. The pH value of the rinsing water is controlled at 6.5~7.0, and finally an inert aggregate with SiO2+Al2O3 content >75% is obtained. The TCLP leaching concentrations of lead, chromium and nickel are less than 0.03mg / L, 0.02mg / L and 0.05mg / L, respectively. The heavy metal recovery system adopts a multi-stage integrated design: flue gas containing heavy metal ammonium salts is quenched and then enters a pulse bag filter. The filter bag surface is covered with a PTFE membrane with a pore size of 0.5μm, and the collection efficiency is >99.9%. The collected metal ammonium salt dust is introduced into a dissolution tank. A 15% dilute sulfuric acid solution is added to the tank and the liquid-solid ratio is maintained at 5:

1. The tank is stirred at 50℃ for 30 minutes to fully dissolve zinc ammonium salt and lead ammonium salt. After insoluble substances are removed by a precision filter, the solution enters a four-chamber electrowinning cell. The anode is a titanium-based iridium-tantalum coated plate, and the cathodes are stainless steel plates and aluminum plates, respectively. Selective electrowinning is carried out under the conditions of current density of 300 A / m² in the zinc region and 150 A / m² in the lead-cadmium region. Electrowinning product processing: The zinc cathode is stripped every 8 hours and then vacuum-cast to obtain zinc ingots with a purity of 99.8%. The lead-cadmium deposits are dissolved in dilute nitric acid and then separated by solvent extraction. The organic phase is selected from the 20% tributyl phosphate-kerosene system, and the final product is a lead-cadmium alloy with Pb:Cd=85:15 and 99.5% pure cadmium. The wastewater from the entire process is neutralized and precipitated before being reused in the water quenching system, achieving a heavy metal recovery rate of >92% for zinc, >95% for lead, and >88% for cadmium, with no secondary waste discharge.

8. A multi-purpose integrated utilization system for waste incinerator flue gas as described in claim 7, characterized in that... It lies in: The intelligent control system constructs a three-layer monitoring-execution architecture. K-type armored thermocouples and anti-clogging Pitot tubes are installed at the waste heat boiler outlet, sludge dryer inlet, and pollutant removal tower of the flue gas energy cascade utilization module to collect temperature and pressure data in real time. Current transformers and infrared thermometers are integrated on the electrode columns of the fly ash melting furnace to continuously monitor the melting state. The core control cabinet adopts a redundant PLC system with a main processor processing cycle of ≤10ms and a built-in multivariable coupled control algorithm: when the flue gas calorific value fluctuation is detected to exceed the set threshold, the material-energy balance compensation mechanism is automatically activated. First, the opening of the flue gas diversion valve is adjusted at a rate of 10% / s to maintain the sludge dryer inlet temperature at 185±5℃. At the same time, the activated carbon injection amount is proportionally corrected, with a 0.05g / Nm³ change in injection amount corresponding to every 100kcal / Nm³ change in calorific value. The power of the melting furnace is dynamically adjusted based on the online analysis results of the fly ash heavy metal content. For every 100mg / kg increase in lead content, the electrode current is increased by 2%. Hard interlock protection is set up for sudden system failures: when the pressure difference of the bag filter is >1500Pa, the adsorbent injection is immediately cut off and the bypass flue is started; when the temperature of the melting furnace is below 1400℃ for 30 seconds, auxiliary fuel is automatically injected, and the natural gas flow rate is adjustable from 0 to 50m³ / min; when the oxygen content of the flue gas exceeds 8%, the feed valve of the sludge dryer is closed in conjunction with the system. All monitoring data are transmitted to the central monitoring station via an industrial fiber optic ring network. The station is equipped with a 3D visualization platform that renders the flue gas flow trajectory and temperature field distribution in real time. The operation interface is embedded with a fault diagnosis expert database, and an emergency response plan is automatically popped up for abnormal data. The system response delay is ≤200ms. The control program is equipped with a self-learning function: it automatically generates an operation optimization report every 1000 hours of operation, and corrects the key parameter settings based on historical data, so that the system can maintain the pollutant removal efficiency fluctuation range of <±1.5% even under seasonal changes in waste composition.

9. A multi-purpose integrated utilization system for waste incinerator flue gas as described in claim 8, characterized in that... It lies in: The heat recovery optimization method achieves deep energy utilization through a three-stage heat exchange of steam, flue gas, and air. The water vapor generated by the sludge drying system, with a pressure of 0.15 MPa and a temperature of 75~80℃, enters the ejector mixer after the droplets are removed by the demister. The diameter of the mixer throat is designed to be 1 / 4 of the inlet pipe, and the steam flow is ejected at a flow rate of 20 m / s, so that it is fully mixed with the flue gas at 160~170℃ in the front section of the SCR reactor in the Venturi section. The temperature of the mixed flue gas is monitored in real time by a thermocouple array. When the temperature drops below 190℃, the steam injection valve is automatically activated. Through PID regulation with a proportional band of 80% and an integral time of 60s, the flue gas temperature is stabilized at 195±3℃, within the optimal activity window of the denitrification catalyst. This temperature control accuracy is more than 50% higher than that of conventional flue gas heat exchangers. After the SCR reaction, the flue gas at 230-250℃ enters the plate heat exchanger to recover waste heat. The heat exchange plates are made of 0.5mm thick 254SMO super stainless steel laser welded and formed with a plate corrugation angle of 60°, forming cross flow channels to make the flue gas velocity 8m / s and the air velocity 12m / s, with a heat exchange area density of 250m² / m³. The air side adopts a two-stage preheating design: cold air is first preheated to 110°C in the low-temperature section of the heat exchanger, and then heated to 150°C in the high-temperature section. The preheated air is delivered in two routes: 80% of the flow from the main route is connected to the primary air system of the incinerator, and 20% of the flow from the branch route is sent to the combustion air duct of the fly ash melting furnace. The heat exchanger condensate collection system is equipped with an online pH adjustment unit. When the pH of the condensate is detected to be less than 5.5, 10% NaOH solution is automatically injected to neutralize it and maintain the pH value at 6.8~7.2, which meets the closed-loop recycling standard. The entire heat recovery system increases the total thermal efficiency to 86.5%, which is 12 percentage points higher than that of conventional incineration plants.

10. A multi-purpose integrated utilization system for waste incinerator flue gas as described in claim 9, characterized in that... The feature is that the optimization of the ammonium sulfate crystallization process is achieved through precise control of crystallization kinetics. The volume of the conical crystallization tank at the bottom of the reaction tower is designed to be 8m³. The tank wall adopts a double-layer structure: the inner liner is a 4mm thick Hastelloy C276 plate, and the outer jacket is filled with 25℃ circulating cooling water to maintain the temperature gradient of the tank wall. A hyperboloid guide tube is vertically installed at the center of the tank. The guide tube has an upper diameter of 800mm, a lower diameter of 500mm, and a height of 1200mm. The tube wall has 120 spirally distributed Φ10mm guide holes with an inclination angle of 45°. A variable frequency seed generator is installed at the bottom of the guide tube. The generator disc has a diameter of 400 mm and 48 wedge-shaped grooves with a depth of 5 mm evenly distributed on the edge. It continuously releases ammonium sulfate seed crystals with a particle size of 0.2~0.3 mm at a rotation speed of 20 r / min. The seed crystal addition amount is 0.8 wt% of the crystallization mother liquor flow rate. The supersaturation control adopts a dual-parameter feedback mechanism of conductivity and density: an online conductivity meter and a vibrating density meter are installed at the outlet of the guide tube to monitor the changes in the physical properties of the slurry in real time. When the conductivity exceeds 180 mS / cm and the density is >1150 kg / m³, the PLC system automatically increases the opening of the ammonium sulfate mother liquor feed valve at a rate of 5% / s to stabilize the supersaturation in the metastable range of 1.10 ± 0.

02. The crystallized product is fed into a horizontal pusher centrifuge via an overflow weir. The centrifuge drum diameter is 1000 mm, the differential speed is 15 r / min, and it is operated under a separation factor of 800. The water content of the separated ammonium sulfate crystals is ≤0.5%. After being treated in a fluidized bed dryer with hot air at 80℃ for 10 minutes, a cubic crystal product of 1.0~1.5 mm is obtained. The centrifuged mother liquor is introduced into a neutralization and adjustment tank, which is equipped with a pH electrode and an ultrasonic mixer. When the pH is <6.3, a metering pump is started to inject 10% ammonia water. When the pH is >7.2, 30% dilute sulfuric acid is added. Finally, the pH of the mother liquor is precisely controlled at 6.8±0.

1. After the adjusted mother liquor is filtered to remove suspended solids, it is returned to the desulfurization system for recycling. The mother liquor reuse rate is >95% and there is no risk of crystallization salt accumulation.

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