Waste incineration flue gas treatment method with dry deacidification cooperating with SCR catalytic filter bag

Abstract

The invention discloses a waste incineration flue gas treatment method through cooperation of dry-process deacidification and an SCR catalytic filter bag. The technological process comprises the steps of denitration in an SNCR furnace, baking soda dry-process deacidification, activated carbon injection, SCR denitration bag type dust removal and waste heat utilization. Denitration is carried out in the SNCR furnace to remove part of NOx; the baking soda dry-process deacidification tower sprays baking soda powder to efficiently remove acid gas; the activated carbon adsorbs dioxin and heavy metal; the SCR denitration bag type dust collector integrates dust collection and denitration, the outer layer of a filter bag is an expanded polytetrafluoroethylene covering film, and the inner layer of the filter bag is a catalytic felt. And a waste heat utilization device can be selected to recover flue gas heat. According to the method, the flue gas temperature is fully utilized, additional heating is not needed, and operation energy consumption is remarkably reduced. And the device is convenient to transform, and is suitable for flue gas treatment of waste incineration projects after flue gas upgrading.

Description

Technical Field

[0001] The present invention belongs to the field of environmental protection technologies and relates to a method for treating waste incineration flue gas by dry deacidification in cooperation with an SCR catalytic filter bag. Background Art

[0002] With the acceleration of China's urbanization process and the continuous growth of the population, the generation amount of domestic waste has been increasing year by year. As an efficient waste treatment method, waste incineration power generation has played an important role in reducing the volume of waste and recovering energy. However, the flue gas generated during waste incineration contains various pollutants, including acidic gases (such as sulfur dioxide, hydrogen chloride), nitrogen oxides (NOx), dioxins, and heavy metals, etc. If not effectively controlled, it will cause serious pollution to the atmospheric environment and threaten human health and ecological safety. Therefore, the research and application of waste incineration flue gas treatment technologies have become an important topic in the field of environmental protection.

[0003] In recent years, the scale of China's waste incineration power generation industry has been continuously expanding, and the subsequent flue gas emission problems have gradually emerged, attracting extensive attention from all sectors of society. To cope with the increasingly severe environmental pressure, the national and local governments have continuously raised the requirements for waste incineration flue gas emission standards. The "Pollution Control Standard for Domestic Waste Incineration" (GB 18485-2014) issued in 2014 stipulates that the 24-hour average emission limit value of sulfur dioxide (SO2) is 80 mg / m 3 , and the 24-hour average emission limit value of nitrogen oxides (NOx) is 250 mg / m 3 . However, with the enhancement of environmental awareness and the progress of technologies, some regions have started to formulate and implement more stringent local emission standards. For example, a local standard issued by a certain province or city has significantly reduced the 24-hour average emission limit value of sulfur dioxide from 80 mg / m 3 to 20 mg / m 3 , and the 24-hour average emission limit value of nitrogen oxides from 250 mg / m 3 to 80 mg / m 3 , and at the same time, new control requirements for ammonia (NH2) emissions have been added, requiring its concentration not to exceed 8 mg / m 3 . The implementation of these standards has posed higher challenges to the flue gas treatment technologies of waste incineration power generation enterprises.

[0004] Currently, the flue gas treatment process commonly adopted by domestic waste incineration power plants is "SNCR in-furnace denitrification + (rotary atomizer semi-dry method + dry method) acid removal (calcium-based) + activated carbon injection + bag filter". This process uses SNCR (Selective Non-Catalytic Reduction) technology to inject denitrifying agents (such as ammonia water or urea) in the furnace to partially remove some NOx, adopts a combination of semi-dry and dry methods to remove acidic gases, uses activated carbon to adsorb dioxins and heavy metals, and finally removes particulate matter through a bag filter. However, this process has obvious deficiencies when facing the new landmark requirements. First, the SNCR denitrification efficiency is limited, usually only able to remove 30%-50% of NOx, and it cannot meet the requirement of reducing nitrogen oxide emissions to 80 mg / m 3 . Second, the removal efficiency of sulfur dioxide by the semi-dry and dry acid removal is limited by the reaction conditions and the utilization rate of the acid removal agent, and it is difficult to stably reach the emission limit of 20 mg / m 3 . In addition, this process has a weak ability to control ammonia escape and it is difficult to meet the local standards for ammonia emissions.

[0005] To cope with more stringent emission standards, many waste incineration power plants have started to upgrade the existing flue gas treatment system. The commonly adopted upgrade plan is "SNCR in-furnace denitrification + semi-dry acid removal + activated carbon injection + bag filter + SCR denitrification". This plan adds a SCR (Selective Catalytic Reduction) denitrification device on the basis of the traditional process, and uses a catalyst to efficiently remove NO x at a lower temperature, while optimizing the acid removal process to meet the emission requirements of sulfur dioxide and ammonia. However, this upgrade plan has many problems:

[0006] First, the renovation workload is large. New equipment such as SCR reactors and flue gas reheating systems need to be added, resulting in a significant increase in investment costs, usually as high as tens of millions of yuan;

[0007] Second, the operating cost is high. The SCR system requires a large amount of catalyst and reducing agent, and the flue gas is first cooled in the acid removal section and then heated in the flue gas reheating system to meet the flue gas temperature required by the process. Additional heating energy is required during the process, and the energy consumption increases significantly;

[0008] Third, the flue gas resistance increases due to the new equipment, which improves the performance requirements for the induced draft fan, and it may be necessary to replace or upgrade the existing fan;

[0009] Fourth, the new equipment occupies a large area, which is particularly disadvantageous for old power plants with limited space;

[0010] Fifth, a long-term furnace shutdown is required during the renovation, which seriously affects the normal production and economic benefits of the power plant.

[0011] These problems make the traditional upgrade plan face double challenges of technology and economy in practical applications.

[0012] In view of the above problems, it is urgent to develop an efficient, low-cost, and small-footprint flue gas treatment technology to reduce the transformation and operation costs while meeting strict emission standards, and improve the overall economy and environmental benefits of the system. Summary of the invention

[0013] In view of this, the purpose of the present invention is to overcome the shortcomings of the prior art and provide a waste incineration flue gas treatment method that combines dry deacidification with SCR catalytic filter bags to achieve the coordinated and efficient removal of pollutants such as acid gases, nitrogen oxides, dioxins and heavy metals, while reducing the cost of transformation, operating energy consumption and floor space, to meet increasingly stringent emission standards.

[0014] In order to achieve the above object, the present invention provides the following technical solutions:

[0015] A waste incineration flue gas treatment method with dry deacidification and SCR catalytic filter bag, the treatment process adopted is SNCR furnace denitration → baking soda dry deacidification → activated carbon injection → SCR denitration bag dust removal; wherein,

[0016] Denitrification in SNCR furnace: The waste incineration unit is equipped with a SNCR system. The SNCR injector sprays the denitrification agent solution into the waste incinerator to react with NOx and reduce it to N2;

[0017] Baking soda dry deacidification: The baking soda dry deacidification tower is connected to the waste incineration unit, and baking soda powder is sprayed in the baking soda dry deacidification tower to absorb the acid gas in the flue gas;

[0018] Activated carbon injection: The activated carbon injection system is connected to the flue gas pipeline at the outlet of the baking soda dry deacidification tower, and activated carbon is injected to absorb dioxins and heavy metals;

[0019] SCR denitrification bag filter: The SCR denitrification bag filter is connected to the baking soda dry deacidification tower through a flue gas pipeline to remove particulate matter and NOx in the flue gas.

[0020] Furthermore, the treatment process also includes waste heat utilization. A waste heat utilization device is provided after the SCR denitrification bag filter. The waste heat utilization device is connected to the flue gas duct at the outlet of the SCR denitrification bag filter to recover the heat of the flue gas through heat exchange.

[0021] Furthermore, the flue gas heat recovered by the waste heat utilization device is used to heat the turbine condensate.

[0022] Furthermore, the temperature of the high-temperature flue gas at the outlet of the waste incineration unit is in the range of 190-240°C. The dry soda ash deacidification using baking soda has a deacidification efficiency of over 95% in the temperature range of 190-240°C. The high-temperature flue gas is directly connected to the dry soda ash deacidification tower, and baking soda powder is sprayed into the dry soda ash deacidification tower through the storage, preparation, and injection system of baking soda dry powder to absorb acidic gases in the flue gas.

[0023] Furthermore, the storage, preparation, and injection system of baking soda dry powder includes a baking soda storage bin, a baking soda metering module, a grinder, a conveying fan, and a spray gun. After the coarse baking soda powder is metered, it is ground by the grinder into fine powder with a fineness D90 ≤ 20μm and sprayed into the dry soda ash deacidification tower through the conveying fan and the spray gun.

[0024] Furthermore, an SCR reductant evaporation system is also provided on the flue gas pipeline before the inlet of the SCR denitration bag filter to provide reductant for the SCR denitration reaction.

[0025] Furthermore, the SCR reductant evaporation system includes a reductant conveying module, a metering module, a dilution air system, and an ammonia injection grid. The ammonia injection grid is arranged on the flue gas pipeline before the inlet of the SCR denitration bag filter, and the reductant is transported to the ammonia injection grid after pyrolysis and gasification.

[0026] Furthermore, the SCR denitration bag filter includes a filter body and SCR denitration filter bags arranged in the filter body; the outermost layer of the SCR denitration filter bags is expanded polytetrafluoroethylene film, and the inner layer is a composite catalytic felt loaded with catalyst, and the denitration efficiency reaches over 90%.

[0027] Furthermore, the injector of SNCR sprays a denitration agent solution including but not limited to ammonia water or urea into the waste incinerator.

[0028] Furthermore, a sensor for detecting the concentrations of SO2 and HCl is provided at the inlet of the dry soda ash deacidification tower. The sensor is connected to the storage, preparation, and injection system of baking soda dry powder to adjust the amount of baking soda supplied to the flue gas.

[0029] The beneficial effects of the present invention are as follows:

[0030] 1. Efficient and collaborative treatment of pollutants: Through the efficient collaboration of the dry soda ash deacidification technology using baking soda and the SCR denitration bag filter in the temperature range of 190-240°C, the present invention realizes the efficient removal of acidic gases and NOx, ensuring that the flue gas emissions fully meet the strictest local standards.

[0031] 2. Reduce the retrofit cost and floor area: Compared with the traditional retrofit solution (adding the SCR process), the present invention integrates SCR denitration and bag dust removal into the same device, eliminating the independent SCR reactor and its flue gas reheating system, reducing the number of devices and the floor area, and reducing the retrofit cost by about 30%-40%. It is especially suitable for old power plants with limited space.

[0032] 3. Reduce the operating energy consumption: The present invention makes full use of the temperature of the waste incineration flue gas at 190-240°C, without the need for additional flue gas heating devices. The dry soda ash deacidification and SCR denitration both operate efficiently in this temperature range, significantly reducing the energy consumption. At the same time, the waste heat utilization device recovers the heat of the flue gas to heat the condensate water, further improving the energy utilization efficiency and reducing the operating cost.

[0033] 4. Stable and reliable operation, easy maintenance: The SCR denitration filter bag adopts an expanded polytetrafluoroethylene film and composite catalytic felt structure, and the catalyst is located downstream of the filter layer, avoiding dust blockage and abrasion. The operating life reaches 5 years without regeneration (the traditional catalyst needs to be regenerated once every 3 years). The present invention has no risk of catalyst poisoning and blockage, the system operates stably, and the maintenance workload is less than that of the traditional solution.

[0034] 5. Shorten the boiler shutdown time: Due to the high degree of process integration, there is no need for large-scale demolition and construction during the retrofit process, and only some equipment needs to be replaced or upgraded. The boiler shutdown time is shortened by more than 50% compared with the traditional solution, reducing the impact on the power plant production.

[0035] 6. Balance environmental friendliness and economy: The by-product of the dry soda ash deacidification is solid salts, which are convenient for collection and treatment. The operation of the dry soda ash deacidification system can effectively reduce the generation amount of fly ash. The overall system operates stably, with low maintenance costs, and has good economic and environmental benefits.

[0036] Other advantages, objectives and features of the present invention will be described to some extent in the subsequent specification, and to some extent, will be obvious to those skilled in the art based on the study of the following text, or can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be achieved and obtained through the following specification. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be described in detail preferably with reference to the accompanying drawings, where:

[0038] Figure 1 It is a schematic layout diagram of the equipment for the waste incineration flue gas treatment method of dry deacidification synergistic SCR catalytic filter bag in the present invention.

[0039] Reference numerals: 1 - waste incinerator; 2 - waste heat boiler; 3 - dry soda acid removal tower; 4 - SCR denitration bag filter; 5 - waste heat utilization device; 6 - induced draft fan; 7 - chimney; 8 - SNCR system; 9 - activated carbon injection system; 10 - SCR reductant evaporation system; 11 - storage, preparation and injection system of dry soda powder. Detailed implementation manners

[0040] The following specific examples illustrate the implementation manners of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific implementation manners. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the drawings provided in the following embodiments only schematically illustrate the basic concept of the present invention. Without conflict, the following embodiments and the features in the embodiments can be combined with each other.

[0041] Among them, the drawings are only for illustrative purposes, showing only schematic diagrams, not physical diagrams, and cannot be construed as a limitation to the present invention; in order to better illustrate the embodiments of the present invention, some components in the drawings will be omitted, enlarged or reduced, which do not represent the dimensions of actual products; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0042] In the drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components; in the description of the present invention, it should be understood that if there are terms such as "upper", "lower", "left", "right", "front", "rear", etc. indicating the orientation or positional relationship, they are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the terms describing the positional relationship in the drawings are only for illustrative purposes and cannot be construed as a limitation to the present invention. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to specific circumstances.

[0043] A method for treating waste incineration flue gas by dry acid removal in cooperation with SCR catalytic filter bags adopts a treatment process flow of SNCR denitration in the furnace → dry soda acid removal → activated carbon injection → SCR denitration bag dust removal → waste heat utilization; its process system is as Figure 1 shown:

[0044] The SNCR system 8 is connected to the waste incineration unit. The waste incineration unit includes a waste incinerator 1 and a waste heat boiler 2. The injector of the SNCR is used to spray a denitrating agent solution including but not limited to ammonia water or urea into the waste incinerator 1 to react with NOx and be reduced to N2;

[0045] The dry soda ash deacidification system includes a storage, preparation and injection system 11 for dry soda ash and a dry soda ash deacidification tower 3. The dry soda ash deacidification tower 3 is connected to the waste incineration unit, and the storage, preparation and injection system 11 for dry soda ash is used to spray the prepared soda ash powder into the dry soda ash deacidification tower 3 to absorb acidic gases in the flue gas.

[0046] A sensor for detecting the concentrations of SO2 and HCl is provided at the inlet of the dry soda ash deacidification tower 3. The sensor is connected to the storage, preparation and injection system 11 for dry soda ash and is used to adjust the amount of soda ash supplied to the flue gas.

[0047] An activated carbon injection system 9 is used to inject activated carbon into the flue gas pipeline at the outlet of the dry deacidification tower to adsorb harmful substances such as dioxins and heavy metals.

[0048] The SCR reductant evaporation system 10 is connected to the flue gas pipeline at the inlet of the SCR denitrification bag filter 4 and is used to provide a reductant for the SCR denitrification reaction.

[0049] The SCR denitrification bag filter 4 is connected to the dry soda ash deacidification tower 3 through a flue gas pipeline and is used to remove particulate matter and NOx in the flue gas.

[0050] The waste heat utilization device 5 uses a heat exchanger and is installed on the flue gas pipeline at the outlet of the SCR denitrification bag filter 4 to recover the heat of the flue gas and use the heat to heat the condensate of the steam turbine.

[0051] Example 1: Conventional operating conditions of a 500t / d incineration line

[0052] In this example, a flue gas upgrading transformation was carried out on an incineration line with a processing capacity of 500t / d in a certain waste incineration power generation project, so that the processing method of the present invention was adopted. The process flow is: SNCR denitrification in the furnace → dry soda ash deacidification → activated carbon injection → SCR denitrification bag filtration → waste heat utilization. The specific implementation steps are as follows:

[0053] 1. SNCR denitrification in the furnace

[0054] An SNCR system 8 is set on the waste incinerator 1. Ammonia / urea solution is used as the denitrification reductant and is sprayed into the furnace (temperature 850 - 1150°C) through the SNCR injector to react with NOx in the flue gas to generate N2 and water vapor. The initial denitrification efficiency reaches 40%. The standard condition flue gas volume of the incineration line is 89580 Nm 3 / h, and the flue gas temperature is 200°C.

[0055] 2. Dry soda ash deacidification

[0056] Set up a storage, preparation and injection system 11 for dry sodium bicarbonate powder. Coarse sodium bicarbonate powder (D50 = 200 μm) is metered through a sodium bicarbonate storage bin (effective volume 3 m 3 ), ground in a grinder to a fineness of D90 ≤ 20 μm, and the output of the grinder is 167 kg / h. The fine powder is sprayed into the dry sodium bicarbonate deacidification tower 3 through a Roots blower and a spray gun, reacts with acidic gases (such as SO2, HCl, etc.) in the flue gas, and the deacidification efficiency reaches 97%. The dosage of sodium bicarbonate is 8 kg / t of garbage, and the flue gas temperature is maintained at 200 °C.

[0057] 3. Activated carbon injection

[0058] Set up an activated carbon injection system 9, inject activated carbon into the flue gas pipeline at the outlet of the dry sodium bicarbonate deacidification tower 3, with an injection amount of 0.43 kg / t of garbage, adsorb dioxins and heavy metals in the flue gas, and the dioxin removal rate reaches 99%.

[0059] 4. SCR denitration bag filter 4

[0060] Replace the filter bags in the existing dust collector with 967 SCR denitration filter bags (specification Φ160×6000 mm), the filter bag area is 2900 m 2 , and the filtration air velocity is 0.89 m / min. The SCR reductant evaporation system 10 is arranged in the flue at the outlet of the deacidification tower, including a reductant transportation module (reusing the reductant solution storage tank), a metering module, a dilution air system (air volume 2500 m 3 / h, pressure 4200 Pa) and an ammonia injection grid. The urea solution is mixed with hot air generated by a pyrolysis furnace (ammonia production capacity ≥ 4.5 kg / h) and a heater, pyrolyzed to generate ammonia, the ammonia concentration is controlled below 5%, and is sprayed into the inlet flue of the SCR denitration bag filter 4 through the ammonia injection grid. NOx in the flue gas reacts with ammonia under the catalytic action of the SCR denitration filter bags, and the denitration efficiency reaches 90%, and the particulate matter capture efficiency > 99.99%.

[0061] 5. Waste heat utilization

[0062] Install a heat exchanger in the flue at the outlet of the dust collector. The flue gas inlet temperature is 190 °C, and the outlet temperature drops to 140 °C. The heat absorption working medium is the condensate water at the outlet of the low-pressure heater (80 °C), and after heating, it returns to the deaerator (110 °C). The recovered heat is converted into steam at a rate of 2.51 t / h.

[0063] Operation results:

[0064] After testing, the flue gas emission indexes after treatment are: the SO2 concentration is 5 mg / Nm 3 , the NOx concentration is 70 mg / Nm 3 , the particulate matter concentration is 10 mg / Nm 3 , and the ammonia slip concentration is 8 mg / Nm3 The dioxin removal rate is 99%. It operates 8,000 hours a year, with a fly ash volume of 11.89 t / d. The operating cost per ton of waste is 55.43 yuan, the total investment is 9.46 million yuan, and the annual operating cost savings is 5.15 million yuan (compared with the transformation plan of adding the traditional SCR process).

[0065] Example 2: High-load operating conditions of a 500 t / d incineration line

[0066] In this example, the method of the present invention is applied to the flue gas treatment of the same 500 t / d incineration line under high-load operating conditions to verify its adaptability under the conditions of higher flue gas volume and pollutant concentration. The process flow is the same as that of Example 1, and the specific implementation steps are as follows:

[0067] 1. SNCR denitrification in the furnace

[0068] Using ammonia water / urea solution as the denitrification reducing agent, it is sprayed into the waste incinerator 11 through the SNCR injector and reacts with NOx. The denitrification efficiency is still 40%. The flue gas volume is 98,538 Nm 3 / h, and the flue gas temperature is raised to 220°C.

[0069] 2. Dry desulfurization with baking soda

[0070] The dry baking soda desulfurization tower 3 reuses the original semi-dry reaction tower, and the storage, preparation and spraying system 11 of baking soda powder remains unchanged. The coarse baking soda powder is ground by a grinder to D90≤20μm, and the spraying amount is adjusted to 9.2 kg / t of waste to cope with higher SO2 concentration. At a flue gas temperature of 220°C, the desulfurization efficiency reaches over 97%, and SO2 is removed to 10 mg / Nm 3 or less.

[0071] 3. Activated carbon injection

[0072] The injection amount of activated carbon is 0.5 kg / t of waste, which effectively adsorbs dioxin and heavy metals, and the dioxin removal rate is maintained at 99%.

[0073] 4. SCR denitrification bag filter

[0074] Use the same 967 SCR denitrification filter bags (filter bag area 2,900 m 2 , filtration air velocity 0.98 m / min). The operating parameters of the SCR reducing agent evaporation system 10 remain unchanged. The urea solution is pyrolyzed to generate ammonia, and the ammonia injection grid precisely controls the ammonia injection amount to ensure that the NOx removal efficiency ≥90%. Due to the relatively high initial NOx concentration, the final emission concentration is controlled within 70 mg / Nm 3 , and the particulate matter concentration is still lower than 10 mg / Nm 3 .

[0075] 5. Waste heat utilization

[0076] Adjust the operating parameters of the heat exchanger. The flue gas inlet temperature is 210°C, and the outlet temperature drops to 160°C. The condensate water is heated from 80°C to 110°C. The steam equivalent of the recovered heat is 2.51 t / h.

[0077] Operating results:

[0078] After detection, the flue gas emission indexes after treatment are as follows: the SO2 concentration is 10 mg / Nm 3 , the NOx concentration is 70 mg / Nm 3 , the particulate matter concentration is 8 mg / Nm 3 , the ammonia slip concentration is 8 mg / Nm 3 , and the dioxin removal rate is 99%. It operates 8000 hours a year. The fly ash volume is 12.21 t / d. The operating cost per ton of waste is about 58.46 yuan, still lower than 86.35 yuan of adding the traditional SCR process. The system operates stably without catalyst blockage or poisoning.

[0079] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the purpose and scope of the present technical solution, and they should all be covered by the scope of the claims of the present invention.

Claims

1. A method for treating waste incineration flue gas by dry desulfurization in cooperation with an SCR catalytic filter bag, characterized in that, The adopted treatment process flow is SNCR denitration in the furnace → dry soda ash deacidification → activated carbon injection → SCR denitration and bag filter; among which, SNCR denitration in the furnace: An SNCR system is installed on the waste incineration unit. The injector of SNCR sprays the denitration agent solution into the waste incinerator to react with NOx and reduce it to N2. Dry soda ash deacidification: The dry soda ash deacidification tower is connected to the waste incineration unit, and soda ash powder is sprayed in the dry soda ash deacidification tower to absorb acidic gases in the flue gas. Activated carbon injection: The activated carbon injection system is connected to the flue gas pipeline at the outlet of the dry soda ash deacidification tower, and activated carbon is sprayed to adsorb dioxins and heavy metals. SCR denitration and bag filter: The SCR denitration bag filter is connected to the dry soda ash deacidification tower through a flue gas pipeline to remove particulate matter and NOx in the flue gas.

2. The method for treating waste incineration flue gas by dry deacidification combined with SCR catalytic filter bags according to claim 1, wherein: The treatment process flow also includes waste heat utilization. A waste heat utilization device is arranged after the SCR denitration bag filter. The waste heat utilization device is connected to the flue gas pipeline at the outlet of the SCR denitration bag filter to recover the heat of the flue gas through heat exchange.

3. The method for treating waste incineration flue gas by dry deacidification in cooperation with an SCR catalytic filter bag according to claim 2, characterized in that: The heat of the flue gas recovered by the waste heat utilization device is used to heat the condensate of the steam turbine.

4. The method for treating waste incineration flue gas by dry deacidification combined with SCR catalytic filter bags according to claim 1, characterized in that: The temperature of the high-temperature flue gas at the outlet of the waste incineration unit is 190 - 240°C. Utilizing the fact that the dry soda ash deacidification has a deacidification efficiency of over 95% in the temperature range of 190 - 240°C, the high-temperature flue gas is directly connected to the dry soda ash deacidification tower. Through the storage, preparation, and injection system of soda ash powder, soda ash powder is sprayed into the dry soda ash deacidification tower to absorb acidic gases in the flue gas.

5. The method for treating waste incineration flue gas by dry deacidification combined with SCR catalytic filter bags according to claim 4, wherein: The storage, preparation, and injection system of soda ash powder includes a soda ash storage bin, a soda ash metering module, a grinder, a conveying fan, and a spray gun. After the coarse soda ash powder is metered, it is ground by the grinder into fine powder with a fineness D90 ≤ 20μm and sprayed into the dry soda ash deacidification tower through the conveying fan and the spray gun.

6. The method for treating waste incineration flue gas by dry deacidification in cooperation with an SCR catalytic filter bag according to claim 1, characterized in that: An SCR reductant evaporation system is also installed on the flue gas pipeline before the inlet of the SCR denitration bag filter to provide reductant for the SCR denitration reaction.

7. The method for treating waste incineration flue gas by dry deacidification in cooperation with an SCR catalytic filter bag according to claim 6, characterized in that: The SCR reductant evaporation system includes a reductant conveying module, a metering module, a dilution air system, and an ammonia injection grid. The ammonia injection grid is arranged on the flue gas pipeline before the inlet of the SCR denitration bag filter, and the reductant is transported to the ammonia injection grid after pyrolysis and gasification.

8. The method for treating waste incineration flue gas by dry deacidification in cooperation with SCR catalytic filter bags according to claim 1, characterized in that: The SCR denitration bag filter includes a filter body and SCR denitration filter bags arranged in the filter body; the outermost layer of the SCR denitration filter bags is expanded polytetrafluoroethylene film, and the inner layer is a composite catalytic felt loaded with catalyst, and the denitration efficiency reaches over 90%.

9. The method for treating waste incineration flue gas by dry desulfurization synergistic SCR catalytic filter bag according to claim 1, characterized in that: The injector of SNCR sprays the denitration agent solution including but not limited to ammonia water or urea into the waste incinerator.

10. The method for treating waste incineration flue gas by dry desulfurization in cooperation with an SCR catalytic filter bag according to claim 4, wherein: Sensors for detecting the concentrations of SO2 and HCl are installed at the inlet of the dry soda ash deacidification tower. The sensors are connected to the storage, preparation, and injection system of soda ash powder to adjust the amount of soda ash supplied to the flue gas.

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