A waste incinerator high-temperature flue gas treatment system

Abstract

The application discloses a high-temperature flue gas treatment system of a garbage incinerator, which comprises an incinerator, a waste heat boiler, a deacidification reaction tower, a cyclone separator and a wind sorting device; the incinerator, the cyclone separator, the waste heat boiler and the deacidification reaction tower are sequentially connected; the cyclone separator is provided with a high-temperature flue gas inlet and a dechlorination agent feeding port on the side; the wind sorting device is connected with the bottom of the cyclone separator, used for sorting the solid particles collected at the bottom of the cyclone separator, and feeding the dechlorination agent sorted from the solid particles back into the cyclone separator; the high-temperature flue gas output by the incinerator firstly enters the cyclone separator to perform dechlorination and dust removal, then enters the waste heat boiler to perform waste heat utilization, and finally enters the deacidification reaction tower to perform deacidification reaction with lime milk spraying; the flue gas after deacidification is further purified by a dust removal system and then discharged. The application has the advantages of compact structure, high dechlorination efficiency, reduced ash deposition and slagging rate of the waste heat boiler, and improved boiler heat exchange efficiency.

Description

Technical Field

[0001] This invention belongs to the field of flue gas treatment technology, and specifically relates to a high-temperature flue gas treatment system for a waste incinerator. Background Technology

[0002] Mechanical grate furnaces are suitable for burning various solid fuels and are widely used in waste incineration. However, due to the high chlorine content in waste, the hydrogen chloride produced during combustion can cause high-temperature chlorine corrosion when it comes into contact with the heated surfaces, jeopardizing equipment safety. Furthermore, mechanical grate furnaces, limited by their structure, cannot achieve efficient dechlorination within the furnace through direct addition of dechlorinating agents or other adsorbents, as is possible with circulating fluidized beds. This means that the heated surfaces are highly susceptible to high-temperature chlorine corrosion from contact with the hydrogen chloride in the high-temperature flue gas.

[0003] During fuel combustion, some of the particulate matter after combustion is carried by the flue gas and enters the waste heat boiler in the form of fly ash, which adheres to the heating surface and forms ash deposits. Due to the complex composition of the fuel, the fly ash is easy to clump together and even block the flue gas flow channels between the heating surfaces, affecting the heat exchange between the flue gas and the heating surface. At the same time, it will also increase the thermal resistance of heat exchange and affect the heat exchange efficiency.

[0004] In the high-temperature environment of the furnace, low-melting-point chlorides quickly evaporate to form FeCl3 vapor, which readily reacts with H2O, SO2, SO3, etc., to produce Fe2(SO4)3 and HCl gas. The FeCl3 condensed on the water-cooled walls continues sulfation while also producing HCl, resulting in a much higher HCl concentration in the deposited layer than in the flue gas. This makes the oxide protective film on the metal surface more susceptible to acid corrosion. Therefore, after fly ash is applied to heated surfaces, the complex composition of the fly ash further exacerbates chlorine corrosion of the heated surfaces.

[0005] Meanwhile, in traditional urban solid waste incineration systems, the flue gas purification system is located after the waste heat boiler. It generally adopts a semi-dry + dry deacidification method to make the flue gas meet environmental emission standards. With its relatively low cost and the advantage of no wastewater generation, it occupies a large market share.

[0006] The semi-dry method involves a very rapid gas-liquid phase reaction between the dechlorinating agent and pollutants in the flue gas. After the moisture in the dechlorinating agent dries, the gas-solid phase reaction is extremely weak. However, the flue gas temperature needs to be maintained above the acid dew point. The moisture in the dechlorinating agent evaporates rapidly, resulting in a short liquid phase duration and a large amount of unreacted dechlorinating agent, leading to waste. For example, in a provincial capital city's waste-to-energy incineration plant, the pre-conversion concentration of HCl in the raw flue gas is approximately 850 mg / Nm³. 3 The pre-conversion concentration of SO2 is approximately 500 mg / Nm³. 3 The net flue gas emission index, HCl concentration before conversion, is <10 mg / Nm³. 3The pre-conversion concentration of SO2 is approximately 50 mg / Nm³. 3 According to production practice data, the utilization rate of dechlorinating agent (calcium hydroxide emulsion) in semi-dry deacidification is about 28% to 38%, and a large amount of dechlorinating agent (slaked lime) is wasted.

[0007] For example, Chinese patent application CN201911000035.4 discloses an in-furnace dechlorination scheme. This scheme uses replaceable adsorbent filter units fixedly positioned in the high-temperature zone before the horizontal flue in the incinerator to achieve flue gas dechlorination. To ensure dechlorination efficiency, the residence time of the flue gas in the adsorbent filter units needs to be extended. The solution proposed in this scheme is to increase the thickness of the filter layer and the number of units, which leads to a significant increase in flue gas flow resistance. Furthermore, the filter units in this scheme are designed as removable drawers, requiring the units to be pulled out for replacement. This can cause high-temperature flue gas leakage during continuous boiler operation, posing risks of environmental pollution and operational safety. Therefore, this scheme has difficulties in practical engineering applications. Summary of the Invention

[0008] The technical problem to be solved by the present invention is to address the shortcomings of existing incineration equipment, such as susceptibility to chlorine corrosion and easy ash and slag buildup in waste heat boilers. The present invention provides a high-temperature flue gas treatment system for waste incinerators that is compact in structure, has high dechlorination efficiency, reduces the rate of ash and slag buildup in waste heat boilers, and is conducive to improving boiler heat exchange efficiency.

[0009] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0010] A high-temperature flue gas treatment system for a waste incinerator 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 in sequence. The side of the cyclone separator is provided with a high-temperature flue gas inlet and a dechlorinating agent inlet. The wind-driven sorting device is connected to the bottom of the cyclone separator and is used to sort the solid particles collected at the bottom of the cyclone separator and to reintroduce 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 enters the dust removal system for further purification before being discharged.

[0011] As a further improvement of the present invention, the output end of the waste heat boiler is provided with a flue gas extraction fan. The output end of the flue gas extraction fan is connected to the wind separation device through a connecting pipe. The flue gas extraction fan extracts the flue gas output from the waste heat boiler and delivers it to the wind separation device to provide the power required for separating the dechlorinating agent, and puts the separated dechlorinating agent back into the cyclone separator.

[0012] As a further improvement of the present invention, the wind-powered sorting device includes a first injector, a rotary ash discharge valve, a wind cap, a sorting bin, and a partition plate; the top of the sorting bin is connected to the bottom of the cyclone separator via a pipe with a valve, and the bottom of the sorting bin is connected to a connecting pipe via a pipe with a valve. The sorting bin is provided with an inclined partition plate, and the partition plate is provided with multiple wind caps. The upper part of the sorting bin is provided with an output pipe with the first injector and an output pipe with the rotary ash discharge valve, and the first injector is connected to the connecting pipe, using the flue gas transported by the connecting pipe to provide the injection power. The output end of the first injector is connected to the cyclone separator via a pipe; the flue gas drawn by the flue gas suction fan is transported through the connecting pipe and enters the sorting bin from the bottom, and screens the solid particles collected on the partition plate, using the density difference of the solid particles to achieve sorting; unreacted dechlorination agent is injected into the cyclone separator through the first injector, and the reacted dechlorination agent is discharged through the rotary ash discharge valve.

[0013] As a further improvement of the present invention, the output end of the flue gas extraction fan is also connected to the bottom of the deacidification reaction tower through a connecting pipe. The flue gas extraction fan extracts the flue gas output from the waste heat boiler and transports it to the bottom of the deacidification reaction tower. This is used to transport the dry particulate matter collected at the bottom of the deacidification reaction tower to the wind-powered sorting device to separate the unreacted slaked lime, and then put the separated slaked lime back into the cyclone separator.

[0014] As a further improvement of the present invention, the bottom of the deacidification reaction tower is provided with a crusher and a second injector. The air inlet of the second injector is connected to the output end of the flue gas extraction fan through a connecting pipe. The dry particulate matter collected by the deacidification reaction tower is transported to the crusher for crushing and then enters the second injector. It is then blown into the air separation device by the flue gas transported by the flue gas extraction fan.

[0015] As a further improvement of the present invention, a vibrator is provided on the outer side of the bottom of the sorting bin. The vibrator is used to vibrate the dechlorinating agent collected on the separator plate after the reaction and discharge it through the rotary ash discharge valve.

[0016] As a further improvement of the present invention, a first monitoring device is provided at the bottom inlet of the sorting chamber to monitor the pressure and flow rate of the flue gas entering the sorting chamber.

[0017] As a further improvement of the present invention, a double-layer flap valve is provided on the top of the sorting chamber, and a slide valve is provided on the pipeline connecting the double-layer flap valve to the bottom of the cyclone separator.

[0018] As a further improvement of the present invention, a second monitoring device and a third monitoring device are respectively provided at the inlet and outlet of the cyclone separator. The second monitoring device is used to monitor the temperature of the high-temperature flue gas entering the cyclone separator and the concentration of hydrogen chloride, and the third monitoring device is used to monitor the temperature of the flue gas output from the cyclone separator and the concentration of hydrogen chloride.

[0019] As a further improvement of the present invention, the contact reaction time between the high-temperature flue gas and the dechlorination agent in the cyclone separator is greater than 5 seconds.

[0020] Compared with the prior art, the advantages of the present invention are as follows:

[0021] 1. The high-temperature flue gas treatment system for waste incinerators of the present invention treats high-temperature flue gas by installing a cyclone separator between the incinerator and the waste heat boiler. This removes particulate impurities entrained in the high-temperature flue gas and utilizes a dechlorinating agent to react with the high-temperature flue gas, reducing the chlorine content in the flue gas and decreasing the fly ash content in the flue gas entering the waste heat boiler. This reduces ash accumulation on the heating surfaces of the waste heat boiler, solving the problem of ash caking on the heating surfaces of the waste heat boiler at its source. During the cooling process of the dechlorinated and dust-removed flue gas in the waste heat boiler, the chlorine content in the flue gas is greatly reduced, and the particulate matter is also reduced. This blocks the Cl source and catalyst amount for the secondary synthesis of dioxins, significantly reducing the amount of dioxins in the flue gas and lowering the risk of chlorine corrosion to the waste heat boiler. At the same time, by installing a wind-powered sorting device at the bottom of the cyclone separator, the solid particles collected at the bottom of the cyclone separator are screened, and the dechlorinating agent separated from the solid particles is reintroduced into the cyclone separator, improving the utilization rate of the dechlorinating agent.

[0022] 2. In the high-temperature flue gas treatment system for waste incinerators of the present invention, the power for the circulation of dechlorinating agent material comes from the flue gas extraction fan. The system resistance is low, and the extraction air temperature is high, generally around 200°C, resulting in a low risk of material blockage and caking. Simultaneously, using waste heat boiler flue gas as the power source for transporting dechlorinating agent material does not increase the additional flue gas losses from the waste heat boiler, minimizing the impact on the economic efficiency of the incinerator system. Furthermore, there is no risk of high-temperature flue gas leakage during operation, ensuring safe and reliable operation.

[0023] 3. The high-temperature flue gas treatment system for waste incinerators of the present invention uses a pneumatic separation device based on the principle of pneumatic separation. The partition plates are arranged at an appropriate angle, and several wind caps are arranged on the partition plates. Flue gas with a certain pressure, provided by a flue gas extraction fan, serves as the separation power. Solid particles discharged from the cyclone separator are screened based on differences in density and particle size, achieving the separation of CaSO4, CaCl2, and CaO. By connecting the top of the pneumatic separation device to the inlet of the cyclone separator, the flue gas blown into the separation device and the screened dechlorinating agent re-enter the cyclone separator for further separation, increasing the concentration of the dechlorinating agent and improving the hydrogen chloride removal efficiency.

[0024] 4. The high-temperature flue gas treatment system for waste incinerators of the present invention, by installing online monitoring devices at both the inlet and outlet of the cyclone separator, acquires the temperature and hydrogen chloride concentration of the inlet and outlet flue gas in real time, and adjusts the dosage of dechlorinating agent based on data feedback, thereby precisely controlling the chlorine content of the flue gas. By controlling the flue gas temperature within the cyclone separator, the dechlorination reaction efficiency is improved.

[0025] 5. In the high-temperature flue gas treatment system for waste incinerator of the present invention, the flue gas after dechlorination enters the waste heat boiler for heat exchange, and then uses atomized lime slurry to carry out semi-dry deacidification in the deacidification reaction tower. The dry slaked lime powder that is not fully utilized after deacidification is pneumatically conveyed to the cyclone separator for secondary utilization, thereby improving the effective utilization rate of materials and indirectly reducing the system operating cost. Attached Figure Description

[0026] Figure 1 This is a schematic diagram illustrating the structural principle of the high-temperature flue gas treatment system for a waste incinerator according to the present invention.

[0027] Figure 2 This is a schematic diagram illustrating the structural principle of the air-powered sorting device in the high-temperature flue gas treatment system of the waste incinerator of the present invention.

[0028] Figure 3 This is a schematic diagram illustrating the principle of the high-temperature flue gas and dechlorinating agent entering and exiting the cyclone separator in the high-temperature flue gas treatment system of the waste incinerator of the present invention.

[0029] Legend: 1. Incinerator; 2. Waste heat boiler; 3. Deacidification reaction tower; 4. Cyclone separator; 5. Slide valve; 6. Air separation device; 61. First injector; 62. Rotary ash discharge valve; 63. Air volume regulating valve; 64. First monitoring device; 65. Vibrator; 66. Double-layer flap valve; 67. Air cap; 68. Separation bin; 69. Divider plate; 7. Slag discharge machine; 8. Second monitoring device; 9. Third monitoring device; 10. Flue gas extraction fan; 11. Crusher; 12. Second injector; 13. Connecting pipe; 14. Heating surface. Detailed Implementation

[0030] The present invention will be further described below with reference to the accompanying drawings and specific preferred embodiments, but this does not limit the scope of protection of the present invention.

[0031] Example

[0032] like Figures 1 to 3 As shown, the high-temperature flue gas treatment system for a waste incinerator of the present invention includes: an incinerator 1, a waste heat boiler 2, a deacidification reaction tower 3, a cyclone separator 4, and a wind-driven separation device 6. The incinerator 1, cyclone separator 4, waste heat boiler 2, and deacidification reaction tower 3 are connected sequentially. The cyclone separator 4 has a high-temperature flue gas inlet and a dechlorinating agent inlet on its side. The wind-driven separation device 6 is connected to the bottom of the cyclone separator 4 and is used to separate the solid particles collected at the bottom of the cyclone separator 4, and to re-inject the dechlorinating agent separated from the solid particles into the cyclone separator 4. The high-temperature flue gas output from the incinerator 1 first enters the cyclone separator 4 for dechlorination and dust removal, then enters the waste heat boiler 2 for waste heat utilization, and finally enters the deacidification reaction tower 3 to undergo a deacidification reaction with quicklime slurry spray. The deacidified flue gas then enters the dust removal system for further purification before being discharged. Using a wind-powered sorting device, small particles of the dechlorinating agent with low density and large specific surface area are separated and connected to the dechlorinating agent circulation system dosing port on the cyclone separator 4. The particles are then transported to the cyclone separator 4 by a pneumatic conveying system for recycling, thereby increasing the concentration of the dechlorinating agent and improving the hydrogen chloride removal efficiency.

[0033] The flue gas from the combustion chamber of the incinerator enters the cyclone separator 4 tangentially. Within the cyclone separator 4, the flue gas rotates downwards tangentially. Dechlorinating agent powder is injected into the cyclone separator 4 in the opposite direction to the flue gas swirl, mixing thoroughly with the flue gas. Inside the cyclone separator 4, the flue gas mixes, reacts, adsorbs, solidifies, and removes hydrogen chloride components from the dechlorinating agent. The resulting ash consists of dechlorinating agent, calcium chloride, and a small amount of calcium sulfite, which falls into the ash hopper under the influence of centrifugal force and gravity as the flue gas flows. Removing HCl and particulate matter from the flue gas before the furnace reduces the amount of deacidifying agent used in the downstream flue gas purification system, thus reducing the generation of hazardous waste (fly ash) and significantly mitigating environmental risks.

[0034] The upper part of the cyclone separator 4 is cylindrical, and the lower part is an inverted conical structure. The flue gas enters tangentially from the side of the cyclone separator 4 and flows downward tangentially and axially inside the cyclone separator 4. The fly ash particles and the injected dechlorination agent powder carried by the flue gas are thrown to the sides of the separator under the action of the centrifugal force of the flue gas swirl and fall into the ash hopper below under the action of gravity.

[0035] It is understandable that the dechlorinating agent can be calcium oxide / calcium hydroxide powder. The reaction rate between the dechlorinating agent and HCl in the flue gas is related to the concentration of HCl in the flue gas; different HCl concentrations result in different reaction rates. To ensure full utilization of the dechlorinating agent, a wind-powered sorting device 6 is installed outside the cyclone separator 4 to achieve dechlorinating agent recycling. The recycling rate of the dechlorinating agent should not be lower than 6 to ensure full utilization of the dechlorinating agent.

[0036] like Figure 3 As shown, two cyclone separators 4 can be installed on the side of the incinerator 1. The high-temperature flue gas treatment system of this embodiment is also applicable to the retrofitting of various mechanical grate furnaces. The cyclone separators 4 can remove large particles of fly ash in the flue gas in advance through cyclone dust removal, greatly reducing the rate of ash accumulation and slagging in the waste heat boiler 2. This slows down chlorine corrosion and also reduces the thermal resistance of ash accumulation and slagging in the waste heat boiler 2, indirectly improving the heat exchange efficiency of the waste heat boiler 2. The mixture of dechlorinating agent particles, deacidification reaction products, and fly ash collected at the bottom of the cyclone separators 4 is separated by the wind-powered sorting device 6. The finer particles contain a large number of unreacted dechlorinating agent particles with a large specific surface area and high reactivity. These are recycled and injected back into the cyclone separators 4 for reuse, extending the dechlorinating agent reaction time and thus achieving efficient utilization of the dechlorinating agent.

[0037] like Figure 1 As shown, in this embodiment, the output end of the waste heat boiler 2 is equipped with a flue gas extraction fan 10. The output end of the flue gas extraction fan 10 is connected to the air separation device 6 through a connecting pipe 13. The flue gas extraction fan 10 extracts the flue gas output from the waste heat boiler 2 and delivers it to the air separation device 6 to provide the power required for separating the dechlorinating agent. The separated dechlorinating agent is then reintroduced into the cyclone separator 4. The flue gas extraction fan 10 uses frequency conversion control or baffle control to adjust the flue gas volume, thereby adjusting the reaction temperature within the cyclone separator 4.

[0038] like Figure 2As shown, the wind-powered sorting device 6 includes a first injector 61, a rotary ash discharge valve 62, an air cap 67, a sorting chamber 68, and a partition plate 69. The top of the sorting chamber 68 is connected to the bottom of the cyclone separator 4 via a pipe with a valve, and the bottom of the sorting chamber 68 is connected to the connecting pipe 13 via a pipe with a valve. The sorting chamber 68 is equipped with an inclined partition plate 69, which has multiple air caps 67. The upper part of the sorting chamber 68 is equipped with an output pipe with the first injector 61 and an output pipe with the rotary ash discharge valve 62. The first injector 61 is connected to the connecting pipe 13, and the flue gas transported by the connecting pipe 13 provides the injection power. The output end of the first injector 61 is connected to the cyclone separator 4 via a pipe. The flue gas drawn by the flue gas extraction fan 10 is transported through the connecting pipe 13 and enters the sorting chamber 68 from the bottom. The flue gas then screens the solid particles collected on the partition plate 69, achieving sorting by utilizing the density difference of the solid particles. Unreacted dechlorinating agent is injected into cyclone separator 4 via first injector 61, and reacted dechlorinating agent is discharged via rotary ash discharge valve 62. First injector 61 can specifically be a Venturi injector.

[0039] In this embodiment, the flue gas carrying the dechlorinating agent is extracted from the exhaust flue of the waste heat boiler 2. Utilizing the waste heat boiler flue gas for transport can reduce boiler exhaust heat loss. Simultaneously, during pneumatic transport, any unreacted dechlorinating agent can react with acidic gases in the extracted gas, prolonging the contact time between the dechlorinating agent and the flue gas, thus achieving efficient utilization of the dechlorinating agent.

[0040] like Figure 1 As shown, in this embodiment, the output end of the flue gas extraction fan 10 is also connected to the bottom of the deacidification reaction tower 3 through the connecting pipe 13. The flue gas extraction fan 10 extracts the flue gas output from the waste heat boiler 2 and transports it to the bottom of the deacidification reaction tower 3. This is used to transport the dry particulate matter collected at the bottom of the deacidification reaction tower 3 to the wind separation device 6 to separate the unreacted slaked lime and put the separated slaked lime back into the cyclone separator 4.

[0041] The main components of the dried particulate matter after deacidification in deacidification reaction tower 3 are unreacted slaked lime, calcium chloride, calcium sulfite, calcium sulfate, and some fly ash carried in the flue gas. For example... Figure 1 As shown, in this embodiment, the bottom of the deacidification reaction tower 3 is equipped with a crusher 11 and a second injector 12. The air inlet of the second injector 12 is connected to the output of the flue gas extraction fan 10 through a connecting pipe 13. The dry particulate matter collected in the deacidification reaction tower 3 is transported to the crusher 11 for crushing and then enters the second injector 12. It is then blown by the flue gas transported by the flue gas extraction fan 10 into the air separation device 6. The second injector 12 can specifically be a Venturi jetting device.

[0042] In this embodiment, a flue gas extraction fan 10 is arranged at the output end of the waste heat boiler 2 to extract a small amount of flue gas from the outlet of the waste heat boiler 2. The outlet pipe of the fan is divided into two paths, both equipped with venturi tubes for extracting and blowing solid powder falling from the bottom of the deacidification reaction tower 3 and the bottom of the cyclone separator 4 via the air-force separation device 6. One path passes through the bottom of the deacidification reaction tower 3, conveying the deacidified mixed particles falling from the bottom of the deacidification reaction tower 3 to the separation device at the bottom of the cyclone separator 4 for screening. The other path is connected to the air-force separation device 6 at the bottom of the cyclone separator 4, conveying the recycled material (dechlorinating agent and the mixture after deacidification in the reaction tower) screened by the air-force separation device 6 to the feed inlet of the cyclone separator 4.

[0043] like Figure 2 As shown, in this embodiment, a vibrator 65 is provided on the outer side of the bottom of the sorting bin 68. The vibrator 65 is used to vibrate the dechlorinating agent collected on the separator plate 69 after the reaction, and discharge it through the rotary ash discharge valve 62. In this embodiment, the solid waste that has no reuse value discharged through the rotary ash discharge valve 62 finally enters the slag discharge machine 7.

[0044] like Figure 2 As shown in this embodiment, a first monitoring device 64 is provided at the bottom inlet of the sorting chamber 68 to monitor the pressure and flow rate of the flue gas entering the sorting chamber 68, so as to ensure that the material in the sorting chamber 68 is in a slightly boiling state, which facilitates the sieving of unreacted quicklime and the CaSO4 and CaCl2 generated by the reaction.

[0045] like Figure 2 As shown, in this embodiment, a double-layer flap valve 66 is provided on the top of the sorting chamber 68, and a slide valve 5 is provided on the pipeline connecting the double-layer flap valve 66 and the bottom of the cyclone separator 4.

[0046] like Figure 1 As shown, in this embodiment, a second monitoring device 8 and a third monitoring device 9 are respectively provided at the inlet and outlet of the cyclone separator 4. The second monitoring device 8 is used to monitor the temperature of the flue gas entering the cyclone separator 4 and the concentration of hydrogen chloride, and the third monitoring device 9 is used to monitor the temperature of the flue gas output from the cyclone separator 4 and the concentration of hydrogen chloride.

[0047] In this embodiment, the dechlorinating agent used is calcium oxide / calcium hydroxide, and the deacidifying agent in the flue gas purification system is calcium hydroxide. Calcium oxide is utilized because it has high dechlorination efficiency at temperatures between 600℃ and 800℃. Furthermore, the most efficient dechlorination temperature range is between 600℃ and 700℃. To ensure the dechlorinating agent reaction temperature is within acceptable limits, a suitable heating surface 14 can be arranged before the cyclone separator 4 to reduce the flue gas temperature and ensure that the flue gas temperature entering the cyclone separator 4 is within the efficient reaction range. Simultaneously, an insulation layer (i.e., refractory lining material) should be installed inside the cyclone separator 4 to ensure the temperature inside the cyclone separator 4 is within acceptable limits. The temperature inside the cyclone separator 4 can be appropriately adjusted by the flow rate of the flue gas used to transport the dechlorinating agent material.

[0048] In this embodiment, to ensure a complete reaction between HCl gas and the dechlorinating agent in the flue gas, the contact reaction time between the high-temperature flue gas and the dechlorinating agent within the cyclone separator 4 should be greater than 5 seconds. Therefore, the cyclone separator needs to be specifically designed according to the incinerator's design parameters. Taking an incinerator with a daily municipal solid waste processing capacity of 850 t / d as an example, the designed flue gas flow rate is D. y =159kNm 3 / h. The flue gas flow rate at 800℃ is approximately D. y ’ =159×(273+800) / (273+20)=587.7m 3 / h. The equivalent flue gas flow rate is approximately d. y ’ =163.15m 3 / h. To achieve the goal of the flue gas residing in the cyclone separator for 5 seconds, there are requirements for the diameter and height of the cyclone separator. At the same time, in order to ensure the smooth flow of ash accumulated at the bottom of the cyclone separator and prevent ash bridging and blockage, the angle between the cone line and the horizontal plane should not be too small (greater than 70°).

[0049] This embodiment proposes a deacidification and dust removal system after the combustion chamber and before the waste heat boiler. It also recycles the deacidifying agent material that is not fully utilized in the semi-dry deacidification process in the flue gas purification system after the waste heat boiler, thus solving problems such as high-temperature corrosion (chlorine corrosion) of the heating surface, blockage of the flow channel between the heating surface tubes due to ash caking on the heating surface, and low utilization rate of the semi-dry deacidifying agent material in flue gas purification.

[0050] While the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the invention. Any person skilled in the art can make many possible variations and modifications to the technical solutions of the present invention, or modify them into equivalent embodiments, without departing from the spirit and technical essence of the invention. Therefore, any simple modifications, equivalent substitutions, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention, without departing from the content of the present invention, shall still fall within the scope of protection of the present invention.

Claims

1. A high-temperature flue gas treatment system for a waste incinerator, characterized in that, include: The incinerator (1), waste heat boiler (2), deacidification reaction tower (3), cyclone separator (4), and wind separation device (6) are connected in sequence. The side of the cyclone separator (4) is provided with a high-temperature flue gas inlet and a dechlorinating agent inlet. The wind separation device (6) is connected to the bottom of the cyclone separator (4) and is used to separate the solid particles collected at the bottom of the cyclone separator (4) and to re-inject the dechlorinating agent separated from the solid particles into the cyclone separator (4). The high-temperature flue gas output from the incinerator (1) first enters the cyclone separator (4) for dechlorination and dust removal, then enters the waste heat boiler (2) for waste heat utilization, and finally enters the deacidification reaction tower (3) to react with quicklime slurry spray for deacidification. The flue gas after deacidification enters the dust removal system for further purification before being discharged. The output end of the waste heat boiler (2) is equipped with a flue gas extraction fan (10). The output end of the flue gas extraction fan (10) is connected to the wind separation device (6) through a connecting pipe (13). The flue gas extraction fan (10) extracts the flue gas output from the waste heat boiler (2) and delivers it to the wind separation device (6) to provide the power required for separating the dechlorinating agent. The separated dechlorinating agent is then put back into the cyclone separator (4). The wind-powered sorting device (6) includes a first injector (61), a rotary ash discharge valve (62), an air cap (67), a sorting bin (68), and a partition plate (69). The top of the sorting bin (68) is connected to the bottom of the cyclone separator (4) via a pipe with a valve, and the bottom of the sorting bin (68) is connected to the connecting pipe (13) via a pipe with a valve. The sorting bin (68) is provided with an inclined partition plate (69), and the partition plate (69) is provided with multiple air caps (67). The upper part of the sorting bin (68) is provided with an output pipe with the first injector (61) and an output pipe with the rotary ash discharge valve (62). The first injector (61) is connected to the connecting pipe (13), and the flue gas transported by the connecting pipe (13) provides the injection power. The output end of the first injector (61) is connected to the cyclone separator (4) through the pipeline. The flue gas drawn by the flue gas suction fan (10) is transported through the connecting pipe (13) and enters the sorting chamber (68) from the bottom of the sorting chamber (68). The solid particles collected on the partition plate (69) are screened and sorted by the density difference of the solid particles. The unreacted dechlorinating agent is injected into the cyclone separator (4) through the first injector (61), and the dechlorinating agent after reaction is discharged through the rotary ash discharge valve (62).

2. The high-temperature flue gas treatment system for a waste incinerator according to claim 1, characterized in that, The output end of the flue gas extraction fan (10) is also connected to the bottom of the deacidification reaction tower (3) through the connecting pipe (13). The flue gas extraction fan (10) extracts the flue gas output from the waste heat boiler (2) and transports it to the bottom of the deacidification reaction tower (3). The dry particles collected at the bottom of the deacidification reaction tower (3) are transported to the wind separation device (6) to separate the unreacted quicklime and put the separated quicklime back into the cyclone separator (4).

3. The high-temperature flue gas treatment system for a waste incinerator according to claim 2, characterized in that, The bottom of the deacidification reaction tower (3) is equipped with a crusher (11) and a second injector (12). The air inlet of the second injector (12) is connected to the output of the flue gas extraction fan (10) through a connecting pipe (13). The dry particulate matter collected by the deacidification reaction tower (3) is transported to the crusher (11) for crushing and then enters the second injector (12), and is blown into the air separation device (6) by the flue gas transported by the flue gas extraction fan (10).

4. The high-temperature flue gas treatment system for a waste incinerator according to any one of claims 1 to 3, characterized in that, The bottom outer side of the sorting bin (68) is provided with a vibrator (65), which is used to vibrate the dechlorinating agent collected on the separator plate (69) after the reaction and discharge it through the rotary ash discharge valve (62).

5. The high-temperature flue gas treatment system for a waste incinerator according to any one of claims 1 to 3, characterized in that, A first monitoring device (64) is provided at the bottom inlet of the sorting chamber (68) to monitor the pressure and flow rate of the flue gas entering the sorting chamber (68).

6. The high-temperature flue gas treatment system for a waste incinerator according to any one of claims 1 to 3, characterized in that, The top of the sorting chamber (68) is equipped with a double-layer flap valve (66), and a slide valve (5) is provided on the pipeline connecting the double-layer flap valve (66) and the bottom of the cyclone separator (4).

7. The high-temperature flue gas treatment system for a waste incinerator according to any one of claims 1 to 3, characterized in that, The cyclone separator (4) is provided with a second monitoring device (8) and a third monitoring device (9) at its inlet and outlet, respectively. The second monitoring device (8) is used to monitor the temperature of the high-temperature flue gas entering the cyclone separator (4) and the concentration of hydrogen chloride. The third monitoring device (9) is used to monitor the temperature of the flue gas output from the cyclone separator (4) and the concentration of hydrogen chloride.

8. The high-temperature flue gas treatment system for a waste incinerator according to any one of claims 1 to 3, characterized in that, The high-temperature flue gas and the dechlorinating agent react in the cyclone separator (4) for more than 5 seconds.

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