Flue gas purification device with synergistic calcium-based absorbent and sodium-based absorbent and control method

Abstract

The invention relates to the technical field of flue gas purification, in particular to a calcium-based absorbent and sodium-based absorbent synergistic flue gas purification device and a control method. The flue gas purification device comprises an incinerator, a transition flue, a pre-dedusting ash hopper, a dry type deacidification tower, a dust and nitrate integrated device, an external economizer, an induced draft fan and a chimney which are sequentially connected through a flue, the incinerator is communicated with a calcium-based absorbent injection system, and the dry type deacidification tower is communicated with a sodium-based absorbent injection system and an activated carbon injection system. And the inlet of the dust-nitrate integrated device is communicated with an SCR reducing agent preparation system. According to the method, the calcium-based absorbent is sprayed into the area with the flue gas temperature of 350-550 DEG C of the incinerator for primary deacidification, so that the occupied area is reduced, the method is suitable for projects which are compactly arranged, the equipment investment and the running resistance of a flue gas and air system can be reduced, the fly ash output and the fly ash treatment cost are reduced, the utilization rate of the calcium-based absorbent is increased, and the environmental pollution is reduced. And the usage amount of the sodium-based absorbent is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of flue gas purification, and in particular to a flue gas purification device and control method that synergistically use calcium-based absorbent and sodium-based absorbent. Background Art

[0002] Most traditional flue gas purification process devices simply stack and connect different flue gas treatment technologies in series without considering the co-treatment of various pollutants, resulting in a long overall process flow, high raw material consumption, high energy consumption, and large investment. In recent years, the technology of co-disposing multiple flue gas pollutants has been increasingly applied because of its short process route, compact equipment layout, small site occupation, low energy consumption, extremely low water consumption during the treatment process, and no generation of any wastewater.

[0003] CN116651168A discloses a dry multi-pollutant flue gas purification device and method, which uses hydrated lime and baking soda as double absorbents to synergistically remove acid. By using hydrated lime with lower activity and lower price for preliminary acid removal in the medium-temperature zone, and then using baking soda with better activity and higher price for fine acid removal in the medium-low temperature zone, it can not only reduce the absorbent cost required for acid removal, but also ensure the overall acid removal efficiency, solving the problems of large consumption of sodium-based absorbent and high operating cost when the existing flue gas purification device sprays in the medium-low temperature zone. This technology requires the flue gas to be purified to be led out from the temperature range of 300 - 600 °C of the waste heat boiler and enter the primary dry acid removal tower, and hydrated lime is used to conduct preliminary flue gas acid removal control in the primary dry acid removal tower. However, there are still the following problems in actual use: (1) For projects that have been put into production, the layout is usually relatively compact, and it is difficult to add a primary acid removal tower; (2) For new projects or projects that can add a primary acid removal tower, due to the increase in the resistance of the flue gas and air system and the increase in equipment investment after adding the primary acid removal tower, the economic benefits of the project are reduced; (3) For waste incineration power generation projects, after adding a primary acid removal tower, the amount of fly ash generated increases sharply. As this fly ash is hazardous waste, the disposal cost is relatively high, further reducing the economic benefits of the project; (4) The ash removal efficiency of the economizer ash hopper is usually not high, and it cannot effectively remove fly ash in the flue gas; (5) A large amount of unreacted hydrated lime is contained in the acid removal ash of calcium-based dry acid removal. However, due to the surface of the unreacted hydrated lime being wrapped by an ash shell layer, the acid removal effect is not good during recycling, and the utilization rate of hydrated lime is not high. Summary of the Invention

[0004] In view of the above problems in the prior art, the present invention provides a flue gas purification device and control method that synergistically use calcium-based absorbent and sodium-based absorbent.

[0005] In order to solve the above technical problems, the present application provides the following technical solutions: A flue gas purification device with the cooperation of calcium-based absorbent and sodium-based absorbent, comprising an incinerator, a transition flue, a pre-dust removal hopper, a dry desulfurization tower, a dust and NOx integrated device, an external economizer, an induced draft fan, and a chimney connected in sequence through a flue; wherein, the incinerator is connected with a calcium-based absorbent injection system; the dry desulfurization tower is connected with a sodium-based absorbent injection system; the dry desulfurization tower is also connected with an activated carbon injection system; the dust and NOx integrated device refers to a device equipped with catalytic filtration elements inside for removing dust and nitrogen oxides, and the catalytic filtration elements are catalytic filter bags or catalytic ceramic filter pipes; the dust and NOx integrated device inlet is connected with an SCR reductant preparation system; a first CEMS is arranged at the inlet of the dry desulfurization tower, a second CEMS is arranged at the inlet of the chimney, and an inlet pressure transmitter and an outlet pressure transmitter are respectively arranged at the inlet and outlet of the dry desulfurization tower.

[0006] Preferably, the pre-dust removal hopper is composed of an upper wall plate, a first lower wall plate, a second lower wall plate, a first side wall plate, two second side wall plates, a dust storage hopper, and a partition plate. The lower part of the upper wall plate is a semi-circular concave arc plate, and the upper part is a vertical plate, and the vertical plate is connected to the upper edge of one side of the semi-circular concave arc plate; the value range of the radius c of the semi-circular concave arc plate is a ≤ c ≤ 1.5a. The first lower wall plate is a concave arc plate, and the arc surface of the first lower wall plate and the arc surface of the upper wall plate are concentric arcs. The radius e of the first lower wall plate is the sum of the radius c of the upper wall plate and the outlet width a of the transition flue, that is, e = c + a, and the central angle of the first lower wall plate is 90°. The second lower wall plate is a convex arc plate, the second lower wall plate is connected to the first lower wall plate and is tangent at the connection, the radius of the second lower wall plate is equal to the radius c of the upper wall plate, and the central angle of the second lower wall plate is 90°. The partition plate is a concave arc plate, the arc surface of the partition plate and the arc surface of the upper wall plate are parallel arcs, the radius of the partition plate is equal to the radius of the first lower wall plate, the minimum distance f between the partition plate and the first lower wall plate satisfies the following condition, 0.2a ≤ f ≤ 0.5a. The head end of the partition plate and the tail end of the first lower wall plate are in the same vertical plane, the tail end of the partition plate is connected to the first side wall plate, and air holes are provided near the first side wall plate of the partition plate; a dust storage hopper is provided at the lowest part of the pre-dust removal hopper.

[0007] Preferably, the air holes are strip-shaped holes, the width of the strip-shaped holes is equal to the outlet width a of the transition flue, and the length d of the strip-shaped holes satisfies the following condition, (e - f) ≤ d ≤ 0.5a.

[0008] Preferably, the flow area of the transition flue gradually decreases along the flue gas flow direction, that is, the outer wall plate of the transition flue connected to the first lower wall plate of the pre-dust removal hopper is vertically downward, and the inner wall plate of the transition flue connected to the upper wall plate of the pre-dust removal hopper inclines towards the outer wall plate of the transition flue, so that the flue gas flow velocity gradually increases, ensuring that the flue gas flow velocity at the outlet of the transition flue is between 10 and 15 m / s, and the included angle formed by the outer wall plate and the inner wall plate of the transition flue is not greater than 30°.

[0009] Preferably, a dust removal element group is provided in the pre-dust removal hopper. The dust removal element group is composed of at least two rows of dust removal elements. Each dust removal element includes two side plates, a windward plate, a partition plate and a wind blocking plate. The two side plates and the windward plate form a groove structure with an isosceles trapezoid cross-section. The opening of the groove structure faces the flue gas inflow direction. The included angle β formed by the two side plates is between 0° and 60°. The value range of the opening width g of the groove structure is 200-500 mm, and the value range of the depth s of the groove structure is g≤s≤3g. The partition plate is arranged at the center inside the groove structure, is vertically arranged and is perpendicularly connected to the windward plate. The value range of the height u of the partition plate is 0.5s≤u≤0.9s. The upper part of the dust removal element is fixed to the upper wall plate of the pre-dust removal hopper, and the lower part passes through the isolation plate and has a gap with the second lower wall plate. The wind blocking plate closes the groove structure below the isolation plate. The value range of the distance h between two adjacent dust removal elements in the same row is 2g≤h≤3g. The adjacent two rows of dust removal elements are arranged in a staggered manner, and the value range of the distance k between the two rows of dust removal elements is s≤k≤2s.

[0010] The length of each row of dust removal elements increases along the flue gas flow direction, that is, it is ensured that the bottom of the latter row of dust removal elements is lower than the bottom of the previous row of dust removal elements, so as to avoid the flue gas being entrained into the dust removal elements and reducing the dust removal effect.

[0011] Preferably, the calcium-based absorbent is slaked lime, and the sodium-based absorbent is baking soda.

[0012] Preferably, the ash discharge port is communicated with an external discharge pipeline for calcium-based circulating ash.

[0013] Preferably, the dry desulfurization tower in the present invention can be cancelled and replaced by a flue.

[0014] Preferably, the calcium-based absorbent injection system includes a calcium-based absorbent coarse powder silo, a calcium-based circulating ash silo, a metering feeder for the calcium-based absorbent coarse powder silo, a metering feeder for the calcium-based circulating ash silo, a calcium-based absorbent grinder, a fine powder collecting device for the circulating calcium-based absorbent, a powder conveying fan for the calcium-based absorbent grinder, a metering and weighing device for the circulating calcium-based absorbent, a powder conveying fan for the circulating calcium-based absorbent, and a powder conveying and injecting device for the circulating calcium-based absorbent.

[0015] Preferably, the sodium-based absorbent injection system includes a sodium-based absorbent coarse powder silo, a metering feeder for the sodium-based absorbent coarse powder silo, a sodium-based absorbent grinder, a fine powder collecting device for the sodium-based absorbent, a powder conveying fan for the sodium-based absorbent grinder, a metering feeder for the sodium-based absorbent coarse powder silo, a powder conveying fan for the sodium-based absorbent, and a powder conveying and injecting device for the sodium-based absorbent.

[0016] Preferably, the metering and feeding devices for the calcium-based absorbent coarse powder silo and the calcium-based recycled ash silo have remote adjustment functions, and can respectively control the amount of calcium-based absorbent coarse powder and calcium-based recycled ash entering the calcium-based absorbent grinder; the calcium-based absorbent grinder has a remote adjustment function and can control the particle size of the absorbent at the outlet of the calcium-based absorbent grinder as needed (D90≤5-10μm), and an air classifier mill can be selected; the metering and feeding device can be a loss-in-weight scale or a rotary feeder valve and has a remote adjustment function; the metering and weighing device for the recycled calcium-based absorbent has a remote adjustment function and can control the feeding amount of the calcium-based absorbent injected into the incinerator as needed.

[0017] Preferably, the activated carbon injection system includes an activated carbon storage bin, an activated carbon metering and feeding device, an activated carbon powder conveying injector, and an activated carbon powder conveying fan.

[0018] Preferably, the catalytic filter element is an SCR catalytic filter bag or an SCR catalytic ceramic filter cartridge, and the inlet of the dust and nitrate integrated device is connected to an SCR reductant preparation system to provide the reductant required for the SCR reaction.

[0019] Preferably, the SCR reductant is ammonia water, and the SCR reductant preparation system includes an ammonia water storage tank, an ammonia water delivery pump, and an ammonia water atomizing spray gun. The ammonia water in the ammonia water storage tank is transported to the flue at the inlet of the dust and nitrate integrated device by the ammonia water delivery pump and the ammonia water atomizing spray gun.

[0020] Preferably, the external economizer can reduce the flue gas temperature to 90-150°C.

[0021] The present invention also provides a control method for a flue gas purification device with synergistic calcium-based absorbent and sodium-based absorbent, including a calcium-based absorbent control subroutine and a sodium-based absorbent control subroutine.

[0022] The calcium-based absorbent control subroutine includes the following steps: 1) Calculate the critical recycled calcium-based absorbent addition amount Crit_Ca_Recycle, and execute step 2; Among them, Crit_Ca_Recycle = Crit_k_Recycle × Gas_Flow ÷ 1000, with the unit of kg / h, the recycled calcium-based absorbent recycle coefficient Crit_k_Recycle = 20-40, with the unit of g / Nm 3 , Gas_Flow is the flue gas flow measured by the first CEMS, with the unit of Nm 3 / h.

[0023] 2) Judge whether the HCl concentration PV_HCl_1 measured by the first CEMS is greater than or equal to the set critical value Crit_HCl_1 or the SO measured by the first CEMS2 Whether the concentration PV_SO2_1 is greater than or equal to the set critical value Crit_SO2_1. When the judgment result is "yes", step 3 is executed; when the judgment result is "no", step 8 is executed. Among them, Crit_HCl_1 = a × Raw_HCl, Crit_SO2_1 = a × Raw_SO2, Raw_HCl is the average concentration of HCl in the raw flue gas, and Raw_SO2 is the average concentration of SO 2 in the raw flue gas, with the unit of mg / Nm 3 , which can be determined through on-site tests; a = 0.4 - 0.6.

[0024] 3) Judge whether the added amount of recycled calcium-based absorbent PV_Ca_Recycle is greater than the critical added amount of recycled calcium-based absorbent Crit_Ca_Recycle. When the judgment result is "yes", step 4 is executed; when the judgment result is "no", step 12 is executed.

[0025] 4) Set the added amount of recycled calcium-based absorbent equal to the critical added amount of recycled calcium-based absorbent Crit_Ca_Recycle.

[0026] 5) Judge whether the added amount of fresh calcium-based absorbent PV_Ca_Sorbent is greater than the critical added amount of fresh calcium-based absorbent Crit_Ca_Sorbent. When the judgment result is "yes", step 6 is executed; when the judgment result is "no", step 13 is executed. Among them, Crit_Ca_Sorbent can be calculated by the following formula: ; In the formula: Crit_Ca_NSR is the critical calcium-to-acid molar ratio, and the value range is 2.0 - 4.0; Purity_Ca is the purity of the fresh calcium-based absorbent.

[0027] 6) Set the added amount of fresh calcium-based absorbent equal to the critical added amount of fresh calcium-based absorbent Crit_Ca_Sorbent.

[0028] 7) Judge whether to end the automatic control subroutine of the calcium-based absorbent. When the judgment result is "yes", end the automatic control; when the judgment result is "no", execute step 1.

[0029] 8) Judge whether the added amount of fresh calcium-based absorbent is greater than zero. When the judgment result is "yes", step 10 is executed; when the judgment result is "no", step 9 is executed.

[0030] 9) Judge whether the added amount of recycled calcium-based absorbent is greater than zero. When the judgment result is "yes", step 11 is executed; when the judgment result is "no", step 1 is executed.

[0031] 10) Reduce the addition amount of fresh calcium-based absorbent. Preferably, use the PID regulation method for regulation.

[0032] 11) Reduce the addition amount of recycled calcium-based absorbent. Preferably, use the PID regulation method for regulation.

[0033] 12) Increase the addition amount of recycled calcium-based absorbent. Preferably, use the PID regulation method for regulation.

[0034] 13) Increase the addition amount of fresh calcium-based absorbent. Preferably, use the PID regulation method for regulation.

[0035] The sodium-based absorbent control subroutine includes the following steps: 1) Calculate the present value PV_Na_NSR of the sodium-acid molar ratio; Wherein, PV_Na_NSR can be calculated according to the following formula: ; In the formula: PV_Na_Sorbent is the present value of the addition amount of sodium-based absorbent, which can be measured by a sodium-based absorbent metering and weighing device, and the unit is kg / h; Purity_Na is the purity of the sodium-based absorbent; PV_SO2_2 is the SO 2 concentration measured by the second CEMS, and PV_HCl_2 is the HCl concentration measured by the second CEMS.

[0036] 2) Judge whether the HCl concentration PV_HCl_2 measured by the second CEMS is greater than or equal to the set critical value Crit_HCl_2 or whether the SO 2 concentration PV_SO2_2 measured by the first CEMS is greater than or equal to the set critical value Crit_SO2_2. When the judgment result is "yes", execute step 3. When the judgment result is "no", execute step 8.

[0037] 3) Judge whether the present value PV_Na_NSR of the sodium-acid molar ratio is greater than or equal to the set critical sodium-acid molar ratio Crit_Na_NSR. When the judgment result is "yes", execute step 4. When the judgment result is "no", execute step 7; Among them, Crit_Na_NSR = 1.1 - 1.8.

[0038] 4) Judge whether the present value PV_DP_Scrubber of the operating differential pressure of the dry desulfurization tower is less than the set critical operating differential pressure Crit_DP_Scrubber of the dry desulfurization tower. When the judgment result is "yes", execute step 5. When the judgment result is "no", execute step 7; Among them, PV_DP_Scrubber is calculated from the pressure values measured by the pressure transmitters at the inlet and outlet of the dry desulfurization tower, with the unit of Pa; Crit_DP_Scrubber = 500 - 1500 Pa.

[0039] 5) Increase the addition amount of sodium-based recycled ash. Preferably, use the PID regulation method for regulation.

[0040] 6) Determine whether to end the automatic control subroutine of the sodium-based absorbent. When the determination result is "yes", end the automatic control. When the determination result is "no", execute step 1.

[0041] 7) Increase the addition amount of sodium-based absorbent. Preferably, use the PID regulation method for regulation.

[0042] 8) Determine whether the present value PV_Na_NSR of the sodium-acid molar ratio is greater than or equal to the set critical sodium-acid molar ratio Crit_Na_NSR. When the determination result is "yes", execute step 9. When the determination result is "no", execute step 10.

[0043] 9) Reduce the addition amount of sodium-based absorbent. Preferably, use the PID regulation method for regulation.

[0044] 10) Reduce the addition amount of sodium-based recycled ash. Preferably, use the PID regulation method for regulation.

[0045] Compared with the prior art, the flue gas purification device and control method with the cooperation of calcium-based absorbent and sodium-based absorbent of the present invention have at least the following beneficial effects: (1) The flue gas purification device and control method with the cooperation of calcium-based absorbent and sodium-based absorbent provided by the present invention spray calcium-based absorbent in the area where the flue gas temperature of the incinerator is 350 - 550 °C for primary deacidification, replacing the separately provided primary deacidification tower, reducing the floor area, and being suitable for projects with a relatively compact layout; at the same time, since there is no need to set up a separate primary deacidification tower, the equipment investment and the operating resistance of the flue gas and air system can be reduced, improving the economic benefits of the project.

[0046] (2)According to the provisions in the "Engineering Technical Standard for Municipal Solid Waste Incineration Treatment and Energy Utilization" (GB / T 51452-2024), boiler ash refers to "the solid substances discharged from the lower part of the heating surface of the incineration boiler", and fly ash refers to "the powdery solid substances discharged from the flue gas purification system, including the ash discharged from the reaction tower, dust collector, flue, and chimney bottom". According to the provisions in the "Technical Standard for Solidification and Stabilization Treatment of Municipal Solid Waste Incineration Fly Ash", "the collection, storage, and transportation process of fly ash shall comply with the relevant provisions of the current industry standard 'Technical Specification for Collection, Storage, and Transportation of Hazardous Wastes' HJ 2025". Therefore, the disposal cost of fly ash is much higher than that of boiler ash. When an independent primary deacidification tower is set up, the calcium-based absorbent, reaction products, etc. sprayed into the primary deacidification tower need to be disposed of as fly ash (hazardous waste). However, in the present invention, the calcium-based absorbent is sprayed into the area with appropriate flue gas temperature of the incinerator, and the sprayed calcium-based absorbent, reaction products, etc. can be disposed of as boiler ash, which can greatly save the fly ash disposal cost and improve the economic benefits of the project.

[0047] (3)The usual economizer ash hopper removes ash by reducing the flue gas velocity and natural sedimentation, and the ash removal effect is poor. The present invention sets up a pre-dust removal ash hopper to increase the flue gas velocity. First, the ash is aggregated by centrifugal separation for primary separation, and then a dust removal element group is set in the pre-dust removal ash hopper to perform secondary separation on the ash in the flue gas, greatly improving the dust removal effect of the economizer ash hopper and reducing the fly ash disposal cost.

[0048] (4)The present invention circulates and uses the fly ash collected by the pre-dust removal ash hopper as a deacidifying agent, making full use of the calcium-based absorbent. At the same time, due to the recycled use of the fly ash collected by the pre-dust removal ash hopper, the content of the absorbent in the incinerator is greatly increased, the deacidification efficiency of the calcium-based deacidification process is improved, the usage amount of the sodium-based deacidifying agent can be reduced, and the economic benefits of the project are improved.

[0049] (5)The present invention grinds the fly ash collected by the pre-dust removal ash hopper through a calcium-based absorbent grinder to remove the ash shell layer wrapped on the surface of the unreacted slaked lime in the deacidified ash, so that the surface of the unreacted slaked lime can be fully exposed to react with the acidic gas, improving the deacidification effect and the utilization rate of slaked lime.

[0050] The following further describes the flue gas purification device and control method for the cooperation of calcium-based absorbent and sodium-based absorbent of the present invention with reference to the accompanying drawings. Description of the Drawings

[0051] Figure 1 It is a schematic diagram of the flue gas purification device for the cooperation of calcium-based absorbent and sodium-based absorbent of the present invention.

[0052] Figure 2 It is a cross-sectional schematic diagram of the pre-dust removal ash hopper.

[0053] Figure 3 is Figure 2 the A-A view in

[0054] Figure 4 a schematic diagram of the dimensions of the pre-dedusting ash hopper.

[0055] Figure 5 a schematic diagram of the dust removal element group in the pre-dedusting ash hopper.

[0056] Figure 6 a schematic diagram of the dimensions of the dust removal element.

[0057] Figure 7 a three-dimensional schematic diagram of the dust removal element.

[0058] Figure 8 a side view of the dust removal element.

[0059] Figure 9 a logic diagram of the calcium-based absorbent control subroutine of the flue gas purification device with the cooperation of calcium-based absorbent and sodium-based absorbent.

[0060] Figure 10 a logic diagram of the sodium-based absorbent control subroutine of the flue gas purification device with the cooperation of calcium-based absorbent and sodium-based absorbent.

[0061] Among them, 1 - incinerator, 2 - transition flue, 3 - pre-dedusting ash hopper; 4 - dry desulfurization tower, 5 - dust and nitrate integrated device, 6 - external economizer, 7 - induced draft fan, 8 - chimney, 9 - calcium-based absorbent coarse powder silo, 10 - metering feeder for calcium-based absorbent coarse powder silo, 11 - calcium-based absorbent grinder, 12 - circulating calcium-based absorbent fine powder collection device, 13 - powder conveying fan for calcium-based absorbent grinder, 14 - metering and weighing device for circulating calcium-based absorbent, 15 - powder conveying and spraying injector for circulating calcium-based absorbent, 16 - powder conveying fan for circulating calcium-based absorbent, 17 - calcium-based circulating ash silo, 18 - metering feeder for calcium-based circulating ash silo, 19 - sodium-based absorbent coarse powder silo, 20 - sodium-based absorbent grinder, 21 - sodium-based absorbent fine powder collection device, 22 - powder conveying fan for sodium-based absorbent grinder, 23 - metering feeder for sodium-based absorbent coarse powder silo, 24 - powder conveying and spraying injector for sodium-based absorbent, 25 - powder conveying fan for sodium-based absorbent, 26 - ammonia water storage tank, 27 - ammonia water transfer pump, 28 - ammonia water atomizing spray gun, 29 - activated carbon storage bin, 30 - metering feeder for activated carbon, 31 - powder conveying and spraying injector for activated carbon, 32 - powder conveying fan for activated carbon, 33 - sodium-based circulating ash return screw conveyor, 34 - first CEMS, 35 - second CEMS, 36 - inlet pressure transmitter, 37 - outlet pressure transmitter, 38 - calcium-based circulating ash discharge pipeline; 301 - Pre - dust removal hopper flue gas inlet, 302 - First lower wall panel, 303 - Second lower wall panel, 304 - Ash storage hopper, 305 - Upper wall panel, 306 - First side wall panel, 307 - Dust removal element, 308 - Isolation board, 309 - Ash discharge port, 310 - Pre - dust removal hopper flue gas outlet, 311 - Second side wall panel; 3071 - Side plate, 3072 - Windward plate, 3073 - Partition board, 3074 - Wind - blocking plate. Specific implementation mode

[0062] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work belong to the scope of protection of the present invention.

[0063] The basic design parameters of this embodiment are shown in the following table:

[0064] As Figure 1-8 shown, a flue gas purification device with synergistic calcium - based absorbent and sodium - based absorbent includes an incinerator 1, a transition flue 2, a pre - dust removal hopper 3, a dry desulfurization tower 4, a dust and nitrate integrated device 5, an external economizer 6, an induced draft fan 7, and a chimney 8 connected in sequence through a flue. Among them, the incinerator 1 is connected to a calcium - based absorbent injection system, and the calcium - based absorbent is slaked lime. The dry desulfurization tower 4 is connected to a sodium - based absorbent injection system, and the sodium - based absorbent is baking soda. The dry desulfurization tower 4 is also connected to an activated carbon injection system. The dust and nitrate integrated device 5 refers to a device with catalytic filter elements installed inside for removing dust and nitrogen oxides, and the catalytic filter element is a catalytic filter bag (according to actual needs, the dust and nitrate integrated device in "CN116651168B A dry multi - pollutant flue gas purification device and method" can be referred to). The inlet of the dust and nitrate integrated device 5 is connected to an SCR reductant preparation system, and the SCR reductant is ammonia water. A first CEMS 34 is arranged at the inlet of the dry desulfurization tower 4, a second CEMS 35 is arranged at the inlet of the chimney 8, and an inlet pressure transmitter 36 and an outlet pressure transmitter 37 are respectively arranged at the inlet and outlet of the dry desulfurization tower 4.

[0065] The pre-dedusting ash hopper 3 is composed of an upper wall plate 305, a first lower wall plate 302, a second lower wall plate 303, a first side wall plate 306, two second side wall plates 311, a dust storage hopper 304, and a partition plate 308. The lower part of the upper wall plate 305 is a semi-circular concave arc plate, and the upper part is a vertical plate. The vertical plate is connected to the upper edge of one side of the semi-circular concave arc plate. The radius c of the semi-circular concave arc plate is 1100 mm. The first lower wall plate 302 is a concave arc plate. The arc surface of the first lower wall plate 302 and the arc surface of the upper wall plate 305 are concentric arcs. The radius e of the first lower wall plate 302 is the sum of the radius c of the upper wall plate 305 and the outlet width a = 1100 mm of the transition flue 2, that is, e = c + a = 2200 mm, and the central angle of the first lower wall plate 302 is 90°. The second lower wall plate 303 is a convex arc plate. The first lower wall plate 302 and the second lower wall plate 303 are connected and tangent at the connection. The radius of the second lower wall plate 303 is equal to the radius c = 1100 mm of the upper wall plate, and the central angle of the second lower wall plate 303 is 90°. A pre-dedusting ash hopper flue gas inlet 301 is formed between the upper edge of one side of the upper wall plate 305 and the upper edge of the first lower wall plate 302. A pre-dedusting ash hopper flue gas outlet 310 is formed between the upper edge of the other side of the upper wall plate 305 and the upper edge of the first side wall plate 306. The outlet width of the transition flue 2 is equal to the widths of the pre-dedusting ash hopper flue gas inlet 301 and the pre-dedusting ash hopper flue gas outlet 310, all of which are a = 1100 mm. The width between the second lower wall plate 303 and the first side wall plate 306 is a = 1100 mm.

[0066] The partition plate 308 is located inside the pre-dedusting ash hopper 3 and is a concave arc plate. The arc surface of the partition plate 308 and the arc surface of the upper wall plate 305 are parallel arcs. The radius of the partition plate 308 is equal to the radius e = 2200 mm of the first lower wall plate 302. The minimum distance f between the partition plate 308 and the first lower wall plate 302 is 330 mm. The head end of the partition plate 308 and the tail end of the first lower wall plate 302 are in the same vertical plane. The tail end of the partition plate 308 is connected to the inner wall surface of the first side wall plate 306. Vent holes are provided near the first side wall plate 306 of the partition plate 308. The vent holes are strip-shaped holes. The width of the strip-shaped holes is equal to the outlet width a = 1100 mm of the transition flue, and the length d of the strip-shaped holes is 550 mm. The lowest part of the pre-dedusting ash hopper 3 is provided with a dust storage hopper 304, which is connected to the lower edge of the second lower wall plate 303 and the lower edge of the first side wall plate 306. The two second side wall plates 311 are respectively located on the front and rear sides of the pre-dedusting ash hopper 3, that is, they are respectively connected to the front and rear side edges of the upper wall plate 305, the first lower wall plate 302, the second lower wall plate 303, and the first side wall plate 306. A dust discharge port 309 is provided at the bottom of the dust storage hopper 304, and the dust discharge port 309 is respectively connected to the inlet of the calcium-based circulating ash bin 17 and the calcium-based circulating ash external discharge pipeline 38.

[0067] The cross-section of the transition flue 2 is a right trapezoid, and the flow area gradually decreases along the flue gas flow direction. That is, the outer wall plate of the transition flue connected to the first lower wall plate 302 of the pre-dedusting ash hopper 3 is vertically downward, and the inner wall plate of the transition flue connected to the upper wall plate 305 of the pre-dedusting ash hopper 3 is inclined towards the outer wall plate of the transition flue, so that the flue gas flow velocity gradually increases, ensuring that the outlet flue gas flow velocity of the transition flue 2 is between 10 and 15 m / s. The included angle formed by the outer wall plate and the inner wall plate of the transition flue is 30°, the outlet width of the transition flue is 1100 mm, and the length is 3000 mm.

[0068] A dust removal element group is provided in the pre-dedusting ash hopper 3, and the dust removal element group is composed of 3 rows of dust removal elements 307. The dust removal element 307 includes two side plates 3071, a windward plate 3072, a partition plate 3073, and a wind blocking plate 3074. The two side plates 3071 and the windward plate 3072 form a groove structure with an isosceles trapezoid cross-section. The opening of the groove structure faces the flue gas inflow direction. The included angle β formed by the two side plates 3071 is 60°. The opening width g of the groove structure is 200 mm, and the depth s of the groove structure is 400 mm. The partition plate 3072 is arranged at the center inside the groove structure, is vertically arranged and is perpendicularly connected to the windward plate 3072. The height u of the partition plate 3073 is 320 mm. The upper part of the dust removal element 307 is fixed on the upper wall plate 305 of the pre-dedusting ash hopper 3, and the lower part passes through the isolation plate 308 and has a gap with the second lower wall plate 303. The wind blocking plate 3074 closes the groove structure below the isolation plate 308, that is, the front and rear edges of the wind blocking plate 3074 are respectively connected to the edges of the two side plates 3071 below the isolation plate 308. The distance h between two adjacent dust removal elements 307 in the same row is 500 mm, and the adjacent two rows of dust removal elements are arranged in a staggered manner. The distance k between the two rows of dust removal elements is 400 mm.

[0069] The length of each row of dust removal elements shows an increasing trend along the flue gas flow direction, that is, it is ensured that the bottom of the latter row of dust removal elements is lower than the bottom of the previous row of dust removal elements, avoiding the flue gas being entrained into the dust removal elements and reducing the dust removal effect.

[0070] The calcium-based absorbent injection system includes a calcium-based absorbent coarse powder silo 9, a calcium-based recycle ash silo 17, a metering feeder for the calcium-based absorbent coarse powder silo 10, a metering feeder for the calcium-based recycle ash silo 18, a calcium-based absorbent grinder 11, a recycle calcium-based absorbent fine powder collection device 12, a powder conveying fan for the calcium-based absorbent grinder 13 (a negative pressure is formed in the grinding cavity of the calcium-based absorbent grinder and the recycle calcium-based absorbent fine powder collection device through the powder conveying fan for the calcium-based absorbent grinder to suck the materials in the grinder into the fine powder collection device for collection), a metering and weighing device for the recycle calcium-based absorbent 14, a powder conveying fan for the recycle calcium-based absorbent 16, and a powder conveying and injecting device for the recycle calcium-based absorbent 15.

[0071] Among them, the outlet of the calcium-based absorbent coarse powder silo 9 is connected to the metering feeder 10 of the calcium-based absorbent coarse powder silo, the outlet of the calcium-based recycle ash silo 17 is connected to the metering feeder 18 of the calcium-based recycle ash silo, the metering feeder 10 of the calcium-based absorbent coarse powder silo and the metering feeder 18 of the calcium-based recycle ash silo are both connected to the inlet of the calcium-based absorbent grinder 11, the outlet of the calcium-based absorbent grinder 11 is connected to the inlet of the recycled calcium-based absorbent fine powder collection device 12, the upper outlet of the recycled calcium-based absorbent fine powder collection device 12 is connected to the powder conveying fan 13 of the calcium-based absorbent grinder, the lower outlet of the recycled calcium-based absorbent fine powder collection device 12 is connected to the metering and weighing device 14 of the recycled calcium-based absorbent, the outlet of the metering and weighing device 14 of the recycled calcium-based absorbent and the powder conveying fan 16 of the recycled calcium-based absorbent are both connected to the powder conveying injector 15 of the recycled calcium-based absorbent, and the outlet of the powder conveying injector 15 of the recycled calcium-based absorbent is connected to the incinerator 1.

[0072] The sodium-based absorbent injection system includes a sodium-based absorbent coarse powder silo 19, a metering feeder 23 of the sodium-based absorbent coarse powder silo, a sodium-based absorbent grinder 20, a sodium-based absorbent fine powder collection device 21, a powder conveying fan 22 of the sodium-based absorbent grinder, a metering feeder 23 of the sodium-based absorbent coarse powder silo, a powder conveying fan 25 of the sodium-based absorbent, and a powder conveying injector 24 of the sodium-based absorbent.

[0073] Among them, the sodium-based absorbent coarse powder silo 19, the sodium-based absorbent grinder 20, and the sodium-based absorbent fine powder collection device 21 are connected in sequence. The upper outlet of the sodium-based absorbent fine powder collection device 21 is connected to the powder conveying fan 22 of the sodium-based absorbent grinder, the lower outlet of the sodium-based absorbent fine powder collection device 21 is connected to the metering feeder 23 of the sodium-based absorbent coarse powder silo, the outlet of the metering feeder 23 of the sodium-based absorbent coarse powder silo and the powder conveying fan 25 of the sodium-based absorbent are both connected to the powder conveying injector 24 of the sodium-based absorbent, and the outlet of the powder conveying injector 24 of the sodium-based absorbent is connected to the upper inlet of the dry deacidification tower 4.

[0074] The metering feeder 10 of the calcium-based absorbent coarse powder silo and the metering feeder 18 of the calcium-based recycle ash silo have remote adjustment functions, and can respectively control the amount of calcium-based absorbent coarse powder and calcium-based recycle ash entering the calcium-based absorbent grinder 11. The calcium-based absorbent grinder 11 has a remote adjustment function, can control the particle size of the absorbent at the outlet of the calcium-based absorbent grinder 11 (D90≤10μm), and an air classifier mill is selected. The metering feeder selects a loss-in-weight scale and has a remote adjustment function; the metering and weighing device 14 of the recycled calcium-based absorbent has a remote adjustment function and can control the feeding amount of the calcium-based absorbent injected into the incinerator as needed.

[0075] The activated carbon injection system includes an activated carbon storage bin 29, an activated carbon metering feeder 30, an activated carbon powder injection ejector 31, and an activated carbon powder blower 33. The activated carbon storage bin 29 is connected to the activated carbon metering feeder 30. The outlet of the activated carbon metering feeder 30 and the activated carbon powder blower are both connected to the activated carbon powder injection ejector 31. The outlet of the activated carbon powder injection ejector 31 is connected to the sidewall inlet of the dry deacidification tower 4.

[0076] The SCR reducing agent is ammonia water. The SCR reducing agent preparation system includes an ammonia water storage tank 26, an ammonia water delivery pump 27, and an ammonia water atomizing spray gun 28 that are connected in sequence. The ammonia water in the ammonia water storage tank 26 is transported by the ammonia water delivery pump 27 and the ammonia water atomizing spray gun 28 to the flue at the inlet of the dust and nitrate integrated device 5.

[0077] The lower outlet of the dust and nitrate integrated device 5 is connected to a sodium-based circulating ash return screw conveyor 33, and the sodium-based circulating ash return screw conveyor 33 is connected to the sidewall inlet of the dry deacidification tower 4.

[0078] The above-mentioned flue gas purification device with synergistic calcium-based absorbent and sodium-based absorbent is used in a certain flue gas purification project. The control method of the flue gas purification device with synergistic calcium-based absorbent and sodium-based absorbent, combined with Figure 9 、 Figure 10 as shown, includes the following steps: After the flue gas purification device with synergistic calcium-based absorbent and sodium-based absorbent is put into operation, the calcium-based deacidification is controlled by the calcium-based absorbent control subroutine: 1) Calculate the critical circulating calcium-based absorbent addition amount Crit_Ca_Recycle, and execute step 2; Among them, Crit_Ca_Recycle = Crit_k_Recycle × Gas_Flow ÷ 1000 = 3000 kg / h, with the unit of kg / h. The circulating calcium-based absorbent circulation coefficient Crit_k_Recycle = 30, with the unit of g / Nm 3 , Gas_Flow = 100000 Nm 3 / h, which is the flue gas flow measured by the first CEMS, with the unit of Nm 3 / h.

[0079] 2) Judge whether the HCl concentration PV_HCl_1 measured by the first CEMS is greater than or equal to the set critical value Crit_HCl_1 or whether the SO 2 concentration PV_SO2_1 measured by the first CEMS is greater than or equal to the set critical value Crit_SO2_1. When the judgment result is "yes", execute step 3. When the judgment result is "no", execute step 8; Among them, Crit_HCl_1 = a × Raw_HCl = 480, Crit_SO2_1 = a × Raw_SO2 = 300, Raw_HCl = 800 is the average concentration of HCl in the raw flue gas, and Raw_SO2 = 500 is the average concentration of SO 2 in the raw flue gas, with the unit of mg / Nm 3 ; a = 0.6.

[0080] 3) Determine whether the addition amount of the recycled calcium-based absorbent PV_Ca_Recycle is greater than the critical addition amount of the recycled calcium-based absorbent Crit_Ca_Recycle = 3000 kg / h. When the judgment result is "yes", execute step 4; when the judgment result is "no", execute step 12.

[0081] 4) Set the addition amount of the recycled calcium-based absorbent equal to the critical addition amount of the recycled calcium-based absorbent Crit_Ca_Recycle = 3000 kg / h.

[0082] 5) Determine whether the addition amount of the fresh calcium-based absorbent PV_Ca_Sorbent is greater than the critical addition amount of the fresh calcium-based absorbent Crit_Ca_Sorbent. When the judgment result is "yes", execute step 6; when the judgment result is "no", execute step 13; Among them, Crit_Ca_Sorbent can be calculated by the following formula: ; In the formula: Crit_Ca_NSR is the critical calcium-to-acid molar ratio, with a value of 3.0; Purity_Ca is the purity of the fresh calcium-based absorbent, with a value of 90%.

[0083] 6) Set the addition amount of the fresh calcium-based absorbent equal to the critical addition amount of the fresh calcium-based absorbent Crit_Ca_Sorbent.

[0084] 7) Determine whether to end the automatic control subroutine of the calcium-based absorbent. When the judgment result is "yes", end the automatic control; when the judgment result is "no", execute step 1.

[0085] 8) Determine whether the addition amount of the fresh calcium-based absorbent is greater than zero. When the judgment result is "yes", execute step 10; when the judgment result is "no", execute step 9.

[0086] 9) Determine whether the addition amount of the recycled calcium-based absorbent is greater than zero. When the judgment result is "yes", execute step 11; when the judgment result is "no", execute step 1.

[0087] 10) Reduce the addition amount of the fresh calcium-based absorbent and adjust it using the PID regulation method.

[0088] 11) Reduce the addition amount of circulating calcium-based absorbent and adopt the PID regulation method for regulation.

[0089] 12) Increase the addition amount of circulating calcium-based absorbent and adopt the PID regulation method for regulation.

[0090] 13) Increase the addition amount of fresh calcium-based absorbent and adopt the PID regulation method for regulation.

[0091] The sodium-based absorbent control subroutine includes the following steps: 1) Calculate the present value PV_Na_NSR of the sodium-acid molar ratio; Among them, PV_Na_NSR can be calculated according to the following formula: ; In the formula: PV_Na_Sorbent is the present value of the sodium-based absorbent addition amount, which can be measured by the sodium-based absorbent metering and weighing device, and the unit is kg / h; Purity_Na is the purity of the sodium-based absorbent; PV_SO2_2 is the SO2 concentration measured by the second CEMS, and PV_HCl_2 is the HCl concentration measured by the second CEMS.

[0092] 2) Judge whether the HCl concentration PV_HCl_2 measured by the second CEMS is greater than or equal to the set critical value Crit_HCl_2 or whether the SO 2 concentration PV_SO2_2 measured by the first CEMS is greater than or equal to the set critical value Crit_SO2_2. When the judgment result is "yes", execute step 3. When the judgment result is "no", execute step 8.

[0093] 3) Judge whether the present value PV_Na_NSR of the sodium-acid molar ratio is greater than or equal to the set critical sodium-acid molar ratio Crit_Na_NSR. When the judgment result is "yes", execute step 4. When the judgment result is "no", execute step 7; Among them, Crit_Na_NSR = 1.3.

[0094] 4) Judge whether the present value PV_DP_Scrubber of the operating differential pressure of the dry desulfurization tower is less than the set critical operating differential pressure Crit_DP_Scrubber of the dry desulfurization tower. When the judgment result is "yes", execute step 5. When the judgment result is "no", execute step 7; Among them, PV_DP_Scrubber is calculated from the pressure values measured by the pressure transmitters at the inlet and outlet of the dry desulfurization tower, and the unit is Pa; Crit_DP_Scrubber = 800 Pa.

[0095] 5) Increase the addition amount of sodium-based circulating ash and adopt the PID regulation method for regulation.

[0096] 6) Determine whether to end the automatic control subroutine of the sodium-based absorbent. When the determination result is "yes", end the automatic control. When the determination result is "no", execute step 1.

[0097] 7) Increase the addition amount of the sodium-based absorbent and adjust it using the PID regulation method.

[0098] 8) Determine whether the present value PV_Na_NSR of the sodium-to-acid molar ratio is greater than or equal to the set critical sodium-to-acid molar ratio Crit_Na_NSR. When the determination result is "yes", execute step 9. When the determination result is "no", execute step 10.

[0099] 9) Decrease the addition amount of the sodium-based absorbent and adjust it using the PID regulation method.

[0100] 10) Decrease the addition amount of the sodium-based recycled ash and adjust it using the PID regulation method.

[0101] The embodiments described above are only used to describe the preferred embodiments of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. A flue gas purification device using a calcium-based absorbent and a sodium-based absorbent in coordination, characterized in that: The invention comprises an incinerator (1), a transition flue (2), a pre-dust removal ash hopper (3), a dry deacidification tower (4), a dust and saltpeter integrated device (5), an external economizer (6), an induced draft fan (7), and a chimney (8) which are connected in sequence through a flue; the incinerator (1) is connected to a calcium-based absorbent injection system; the dry deacidification tower (4) is connected to a sodium-based absorbent injection system and an activated carbon injection system; the inlet of the dust and saltpeter integrated device (5) is connected to an SCR reducing agent preparation system; the inlet of the dry deacidification tower (4) is provided with a first CEMS (34), the inlet of the chimney (8) is provided with a second CEMS (35), and the inlet and outlet of the dry deacidification tower (4) are also provided with an inlet pressure transmitter (36) and an outlet pressure transmitter (37), respectively.

2. The flue gas purification device in which the calcium-based absorbent and the sodium-based absorbent cooperate according to claim 1 is characterized in that: The pre-dust removal hopper (3) comprises an upper wall plate (305), a first lower wall plate (302), a second lower wall plate (303), a first side wall plate (306), two second side wall plates (311), an ash storage hopper (304), and a separation plate (308); The lower part of the upper wall plate (305) is a semicircular concave arc plate, and the upper part is a vertical plate, and the vertical plate is connected to the upper edge of one side of the semicircular concave arc plate; The first lower wall plate (302) is a concave arc plate, and its arc surface is concentric with the arc surface of the upper wall plate (305); the radius of the first lower wall plate (302) is the sum of the radius of the upper wall plate (305) and the outlet width of the transition flue (2); and the center angle of the lower wall plate (1) is 90°; The second lower wall plate (303) is a convex arc plate and is connected to the first lower wall plate (302) and is tangent to the first lower wall plate (302) at the connection point. The radius of the second lower wall plate (303) is equal to the radius of the upper wall plate (305) and the central angle thereof is 90°. The isolation plate (308) is a concave arc plate, and its arc surface is parallel to the arc surface of the upper wall plate (305); the radius of the isolation plate (308) is equal to the radius of the first lower wall plate (302); the head end of the isolation plate (308) and the tail end of the first lower wall plate (302) are in the same vertical plane, the tail end of the isolation plate (308) is connected to the first side wall plate (306), and the isolation plate (308) is provided with a vent hole near the first side wall plate (306); The flow area of ​​the transition flue (2) gradually decreases along the direction of flue gas flow, and the angle formed by the outer wall plate of the transition flue and the inner wall plate of the transition flue is no greater than 30°.

3. The flue gas purification device in which the calcium-based absorbent and the sodium-based absorbent cooperate according to claim 1 is characterized in that: A dust removal element group is provided in the pre-dust removal hopper (3), the dust removal element group comprising at least two dust removal elements (307), the dust removal element (307) comprising two side plates (3071), a windward plate (3072), a partition plate (3073) and a wind blocking plate (3074), the two side plates (3071) and the windward plate (3072) forming a groove structure with an isosceles trapezoidal cross section, the groove structure opening facing the direction of smoke inflow; the partition plate (3073) is arranged at the center of the groove structure and is vertically arranged and vertically connected to the windward plate (3072); the upper part of the dust removal element (307) is fixed to the upper wall plate of the pre-dust removal hopper, and the lower part passes through the isolation plate (308) and leaves a gap with the second lower wall plate (303), and the wind blocking plate (3074) closes the groove structure below the isolation plate (308).

4. The flue gas purification device in which the calcium-based absorbent and the sodium-based absorbent cooperate according to claim 3 is characterized in that: The length of each dust removal element increases along the flue gas flow direction, and the bottom of the latter dust removal element is lower than the bottom of the former dust removal element.

5. The flue gas purification device using a calcium-based absorbent and a sodium-based absorbent in cooperation with each other according to claim 1, characterized in that: The calcium-based absorbent injection system comprises a calcium-based absorbent coarse powder bin (9), a calcium-based circulating ash bin (17), a calcium-based absorbent coarse powder bin metering feeding device (10), a calcium-based circulating ash bin metering feeding device (18), a calcium-based absorbent grinder (11), a circulating calcium-based absorbent fine powder collecting device (12), a calcium-based absorbent grinder powder conveying fan (13), a circulating calcium-based absorbent metering weighing device (14), a circulating calcium-based absorbent powder conveying fan (16), and a circulating calcium-based absorbent powder conveying injector (15).

6. The flue gas purification device using a calcium-based absorbent and a sodium-based absorbent in cooperation with each other according to claim 1, characterized in that: The sodium-based absorbent injection system comprises a sodium-based absorbent coarse powder bin (19), a sodium-based absorbent coarse powder bin metering feeding device (23), a sodium-based absorbent grinder (20), a sodium-based absorbent fine powder collecting device (21), a sodium-based absorbent grinder powder conveying fan (22), a sodium-based absorbent coarse powder bin metering feeding device (23), a sodium-based absorbent powder conveying fan (25), and a sodium-based absorbent powder conveying injector (24).

7. The flue gas purification device using a calcium-based absorbent and a sodium-based absorbent in cooperation with each other according to claim 1, characterized in that: The activated carbon injection system comprises an activated carbon storage bin (29), an activated carbon metering feeding device (30), an activated carbon powder conveying injector (31), and an activated carbon powder conveying fan (32); The dust and nitrogen integrated device (5) is a device with a catalytic filter element installed inside and having the function of removing dust and nitrogen oxides. The catalytic filter element is a catalytic filter bag or a catalytic ceramic filter tube.

8. The flue gas purification device using a calcium-based absorbent and a sodium-based absorbent in cooperation with each other according to claim 1, characterized in that: The SCR reducing agent preparation system comprises an ammonia water storage tank (26), an ammonia water delivery pump (27) and an ammonia water atomizing spray gun (28); the ammonia water in the ammonia water storage tank (26) is delivered to the flue at the inlet of the dust and saltpeter integrated device (5) by the ammonia water delivery pump (27) and the ammonia water atomizing spray gun (28); the SCR reducing agent is ammonia water.

9. The control method of the flue gas purification device in which the calcium-based absorbent and the sodium-based absorbent cooperate with each other according to any one of claims 1 to 8, characterized in that: The method comprises a calcium-based absorbent control subroutine, wherein the calcium-based absorbent control subroutine comprises the following steps: 1) Calculate the critical cycle calcium-based absorbent addition amount Crit_Ca_Recycle and execute step 2; Among them, Crit_Ca_Recycle=Crit_k_Recycle×Gas_Flow÷1000, the unit is kg / h, the recycling coefficient of the circulating calcium-based absorbent Crit_k_Recycle=20~40, the unit is g / Nm 3 , Gas_Flow is the flue gas flow measured by the first CEMS, in Nm 3 / h; 2) Determine whether the HCl concentration PV_HCl_1 measured by the first CEMS is greater than or equal to the set critical value Crit_HCl_1 or whether the SO2 concentration PV_SO2_1 measured by the first CEMS is greater than or equal to the set critical value Crit_SO2_1. When the judgment result is "yes", execute step 3; when the judgment result is "no", execute step 8; Among them, Crit_HCl_1=a×Raw_HCl, Crit_SO2_1=a×Raw_SO2, Raw_HCl is the average concentration of HCl in the original flue gas, Raw_SO2 is the average concentration of SO2 in the original flue gas, the unit is mg / Nm 3 , determined through field tests; a=0.4~0.6; 3) Determine whether the circulating calcium-based absorbent addition amount PV_Ca_Recycle is greater than the critical circulating calcium-based absorbent addition amount Crit_Ca_Recycle. When the judgment result is "yes", execute step 4; when the judgment result is "no", execute step 12; 4) Set the amount of calcium-based absorbent added in the cycle to be equal to the critical calcium-based absorbent added in the cycle Crit_Ca_Recycle; 5) Determine whether the amount of fresh calcium-based absorbent added PV_Ca_Sorbent is greater than the critical amount of fresh calcium-based absorbent added Crit_Ca_Sorbent. If the determination result is "yes", execute step 6; if the determination result is "no", execute step 13; Among them, Crit_Ca_Sorbent is calculated as follows: ； Where: Crit_Ca_NSR is the critical calcium-acid molar ratio, ranging from 2.0 to 4.0; Purity_Ca is the purity of the fresh calcium-based absorbent; 6) Set the amount of fresh calcium-based absorbent added to be equal to the critical amount of fresh calcium-based absorbent added Crit_Ca_Sorbent; 7) Determine whether to end the calcium-based absorbent automatic control subroutine. When the judgment result is "yes", end the automatic control. When the judgment result is "no", execute step 1; 8) Determine whether the amount of fresh calcium-based absorbent added is greater than zero. If the determination result is "yes", execute step 10; if the determination result is "no", execute step 9; 9) Determine whether the amount of circulating calcium-based absorbent added is greater than zero. When the judgment result is "yes", execute step 11; when the judgment result is "no", execute step 1; 10) Reduce the amount of fresh calcium-based absorbent added and use PID regulation; 11) Reduce the amount of circulating calcium-based absorbent added and use PID regulation; 12) Increase the amount of circulating calcium-based absorbent and adjust it using PID regulation; 13) Increase the amount of fresh calcium-based absorbent and adjust it using PID regulation.

10. The control method of the flue gas purification device in which the calcium-based absorbent and the sodium-based absorbent cooperate according to claim 9 is characterized in that: A sodium-based absorbent control subroutine is included, and the sodium-based absorbent control subroutine includes the following steps: 1) Calculate the present value of the sodium-acid molar ratio PV_Na_NSR; Among them, PV_Na_NSR is calculated as follows: ； Where: PV_Na_Sorbent is the present value of the amount of sodium-based absorbent added, measured by the sodium-based absorbent weighing device, and the unit is kg / h; Purity_Na is the purity of the sodium-based absorbent; PV_SO2_2 is the SO2 concentration measured by the second CEMS, and PV_HCl_2 is the HCl concentration measured by the second CEMS; 2) Determine whether the HCl concentration PV_HCl_2 measured by the second CEMS is greater than or equal to the set critical value Crit_HCl_2 or whether the SO2 concentration PV_SO2_2 measured by the first CEMS is greater than or equal to the set critical value Crit_SO2_2. When the judgment result is "yes", execute step 3; when the judgment result is "no", execute step 8; 3) Determine whether the present value of the sodium-acid molar ratio PV_Na_NSR is greater than or equal to the set critical sodium-acid molar ratio Crit_Na_NSR. When the judgment result is "yes", execute step 4; when the judgment result is "no", execute step 7; Among them, Crit_Na_NSR=1.1~1.8; 4) Determine whether the present value PV_DP_Scrubber of the dry deacidification tower operation differential pressure is less than the set critical dry deacidification tower operation differential pressure Crit_DP_Scrubber. When the judgment result is "yes", execute step 5; when the judgment result is "no", execute step 7; PV_DP_Scrubber is calculated from the pressure value measured by the inlet and outlet pressure transmitters of the dry deacidification tower, and the unit is Pa; Crit_DP_Scrubber = 500~1500Pa; 5) Increase the amount of sodium-based circulating ash added and adjust it using PID regulation; 6) Determine whether to end the sodium-based absorbent automatic control subroutine. When the judgment result is "yes", end the automatic control. When the judgment result is "no", execute step 1; 7) Increase the amount of sodium-based absorbent added and adjust it using PID regulation; 8) Determine whether the present value of the sodium-acid molar ratio PV_Na_NSR is greater than or equal to the set critical sodium-acid molar ratio Crit_Na_NSR. When the judgment result is "yes", execute step 9; when the judgment result is "no", execute step 10; 9) Reduce the amount of sodium-based absorbent added and use PID regulation; 10) Reduce the amount of sodium-based circulating ash added and use PID control method for adjustment.

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