A flue gas purification device and control method using a calcium-based absorbent and a sodium-based absorbent

Abstract

The present invention relates to the field of flue gas purification technology, specifically to a flue gas purification device and control method that uses a calcium-based absorbent and a sodium-based absorbent in combination. The flue gas purification device includes an incinerator, a transition flue, a pre-dust hopper, a dry 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 connected to a calcium-based absorbent injection system, the dry deacidification tower is connected to a sodium-based absorbent injection system and an activated carbon injection system, and the dust and nitrate integrated device inlet is connected to an SCR reducing agent preparation system. The present invention sprays calcium-based absorbent into the region where the flue gas temperature of the incinerator is 350-550°C for primary deacidification, thereby reducing floor space and being suitable for projects with relatively compact layouts. It can reduce equipment investment and the operating resistance of the smoke and air system, reduce the amount of fly ash generated and the cost of fly ash disposal, improve the utilization rate of calcium-based absorbents, and reduce the amount of sodium-based absorbents used.

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 a control method using a calcium-based absorbent and a sodium-based absorbent in coordination. Background Art

[0002] Most traditional flue gas purification processes simply stack and connect different flue gas treatment technologies in series, without considering the coordinated treatment of various pollutants. This results in lengthy processes, high raw material and energy consumption, and large investments. In recent years, the coordinated treatment of multiple pollutants in flue gas has gained increasing application due to its short process route, compact equipment layout, small site footprint, low energy consumption, and extremely low water consumption during the treatment process, resulting in no wastewater generation.

[0003] CN116651168A discloses a dry-process multi-pollutant flue gas purification device and method. This device utilizes slaked lime and baking soda as dual absorbents for synergistic deacidification. By utilizing the less active and inexpensive slaked lime for preliminary deacidification in a medium-temperature zone, and then utilizing the more active and expensive baking soda for refined deacidification in a medium-low temperature zone, this method reduces the cost of the absorbent required for deacidification while ensuring overall deacidification efficiency. This addresses the high sodium-based absorbent consumption and high operating costs associated with existing flue gas purification devices when spraying in the medium-low temperature zone. This technology requires the flue gas to be purified to be drawn from the waste heat boiler (HRSG) in the temperature range of 300-600°C and enter a primary dry deacidification tower, where slaked lime is used for preliminary flue gas deacidification control. However, the following problems still exist in actual use: (1) For projects that have already been put into production, the layout is usually compact, and it is difficult to add a first-stage deacidification tower; (2) For new projects or projects that can add a first-stage deacidification tower, the addition of a first-stage deacidification tower will increase the resistance of the smoke and air system and increase equipment investment, which will reduce the economic benefits of the project; (3) For waste incineration power generation projects, the addition of a first-stage deacidification tower will cause a sharp increase in the amount of fly ash generated. As a hazardous waste, the disposal cost of this fly ash is high, which further reduces the economic benefits of the project; (4) The ash removal efficiency of the conventional economizer ash hopper is not high, and it cannot effectively remove fly ash from the flue gas; (5) The deacidified ash of calcium-based dry deacidification contains a large amount of unreacted slaked lime, but because the surface of the unreacted slaked lime is covered with an ash shell layer, the deacidification effect is poor during recycling, and the utilization rate of slaked lime is not high. Summary of the Invention

[0004] In response to the above-mentioned problems in the prior art, the present invention provides a flue gas purification device and a control method that cooperates with a calcium-based absorbent and a sodium-based absorbent.

[0005] In order to solve the above technical problems, this application provides the following technical solutions:

[0006] A flue gas purification device that cooperates with a calcium-based absorbent and a sodium-based absorbent, comprising an incinerator, a transition flue, a pre-dust hopper, a dry deacidification tower, a dust and nitrate integrated device, an external economizer, an induced draft fan, and a chimney, which are connected in sequence through a flue; wherein the incinerator is connected to a calcium-based absorbent injection system; the dry deacidification tower is connected to a sodium-based absorbent injection system; the dry deacidification tower is also connected to an activated carbon injection system; the dust and nitrate integrated device refers to a device with a catalytic filter element installed inside that has the function of removing dust and nitrogen oxides, and the catalytic filter element is a catalytic filter bag or a catalytic ceramic filter tube; the inlet of the dust and nitrate integrated device is connected to an SCR reducing agent preparation system; the inlet of the dry deacidification tower is provided with a first CEMS, the inlet of the chimney is provided with a second CEMS, and the inlet and outlet of the dry deacidification tower are respectively provided with an inlet pressure transmitter and an outlet pressure transmitter.

[0007] Preferably, the pre-dust hopper is composed of an upper wall panel, a first lower wall panel, a second lower wall panel, a first side wall panel, two second side wall panels, an ash storage hopper, and an isolation plate. The lower portion of the upper wall panel is a semicircular concave arc panel, and the upper portion is a vertical panel, which is connected to the upper edge of one side of the semicircular concave arc panel. The radius c of the semicircular concave arc panel is in the range of a≤c≤1.5a. The first lower wall panel is a concave arc panel, and the arc surface of the first lower wall panel is concentric with the arc surface of the upper wall panel. The radius e of the first lower wall panel is the sum of the radius c of the upper wall panel and the outlet width a of the transition flue, that is, e=c+a. The center angle of the first lower wall panel is 90°. The second lower wall panel is a convex arc panel, which is connected to the first lower wall panel and tangent to each other at the connection. The radius of the second lower wall panel is equal to the radius c of the upper wall panel, and the center angle of the second lower wall panel is 90°. The isolation plate is a concave arc plate, the arc surface of the isolation plate and the arc surface of the upper wall plate are parallel arcs, the radius of the isolation plate is equal to the radius of the first lower wall plate, the minimum distance f between the isolation plate and the first lower wall plate satisfies the following condition, 0.2a≤f≤0.5a, the head end of the isolation plate and the tail end of the first lower wall plate are in the same vertical plane, the tail end of the isolation plate is connected to the first side wall plate, and the isolation plate is provided with a vent near the first side wall plate; an ash storage hopper is provided at the lowest point of the pre-dust removal hopper.

[0008] Preferably, the vent hole is a strip hole, the width of the strip hole is equal to the width a of the transition flue outlet, and the length d of the strip hole satisfies the following condition: (ef)≤d≤0.5a.

[0009] Preferably, the flow area of the transition flue gradually decreases along the direction of the flue gas flow, that is, the outer wall plate of the transition flue connecting the transition flue with the first lower wall plate of the pre-dust hopper is vertically downward, and the inner wall plate of the transition flue connected with the upper wall plate of the pre-dust hopper is inclined toward the outer wall plate of the transition flue, so that the flue gas flow rate gradually accelerates, ensuring that the flue gas flow rate at the outlet of the transition flue is between 10 and 15 m / s, and the angle formed by the outer wall plate of the transition flue and the inner wall plate of the transition flue is not greater than 30°.

[0010] Preferably, a dust removal element group is provided in the pre-dust hopper, and the dust removal element group consists of at least two dust removal elements. The 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 constitute a groove structure with an isosceles trapezoidal cross-section. The opening of the groove structure is toward the direction of flue gas inflow, and the 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 to 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 of the groove structure, is vertically arranged and vertically connected to the windward plate, and the value range of the partition plate height u 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 hopper, and the lower part passes through the isolation plate and leaves a gap with the second lower wall plate; the wind blocking plate closes the groove structure below the isolation plate. The spacing h between two adjacent dust removal elements in the same row ranges from 2g≤h≤3g, the dust removal elements in two adjacent rows are arranged in a staggered manner, and the spacing k between the dust removal elements in two rows ranges from s≤k≤2s.

[0011] The length of each dust removal element tends to increase along the direction of flue gas flow, that is, to ensure that the bottom of the latter dust removal element is lower than the bottom of the former dust removal element, thereby preventing flue gas from being sucked into the dust removal element and causing a reduction in dust removal effect.

[0012] Preferably, the calcium-based absorbent is slaked lime, and the sodium-based absorbent is baking soda.

[0013] Preferably, the ash discharge port is connected to a calcium-based circulating ash discharge pipeline.

[0014] Preferably, the dry deacidification tower in the present invention can be eliminated and replaced by a flue.

[0015] Preferably, the calcium-based absorbent injection system includes a calcium-based absorbent coarse powder bin, a calcium-based circulating ash bin, a calcium-based absorbent coarse powder bin metering feeding device, a calcium-based circulating ash bin metering feeding device, a calcium-based absorbent grinder, a circulating calcium-based absorbent fine powder collection device, a calcium-based absorbent grinder powder conveying fan, a circulating calcium-based absorbent metering and weighing device, a circulating calcium-based absorbent powder conveying fan, and a circulating calcium-based absorbent powder conveying injector.

[0016] Preferably, the sodium-based absorbent injection system includes a sodium-based absorbent coarse powder bin, a sodium-based absorbent coarse powder bin metering feeding device, a sodium-based absorbent grinder, a sodium-based absorbent fine powder collecting device, a sodium-based absorbent grinder powder conveying fan, a sodium-based absorbent powder conveying fan, and a sodium-based absorbent powder conveying injector.

[0017] Preferably, the calcium-based absorbent coarse powder bin metering feeding device and the calcium-based circulating ash bin metering feeding device have a remote adjustment function, which can respectively control the amount of calcium-based absorbent coarse powder and calcium-based circulating ash entering the calcium-based absorbent grinder; the calcium-based absorbent grinder has a remote adjustment function, which can control the particle size of the absorbent at the outlet of the calcium-based absorbent grinder (D90≤5~10μm) as needed, and an air classifying mill can be used; the metering feeding device can use a loss-in-weight scale or a rotary feeding valve, which has a remote adjustment function; the circulating calcium-based absorbent metering weighing device has a remote adjustment function, which can control the amount of calcium-based absorbent fed into the incinerator as needed.

[0018] Preferably, the activated carbon injection system includes an activated carbon storage bin, an activated carbon metering feeding device, an activated carbon powder conveying injector, and an activated carbon powder conveying fan.

[0019] 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 saltpeter integrated device is connected to an SCR reducing agent preparation system to provide the reducing agent required for the SCR reaction.

[0020] Preferably, the SCR reducing agent is ammonia water, and the SCR reducing agent 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 delivered to the flue at the inlet of the dust and saltpeter integrated device by the ammonia water delivery pump and the ammonia water atomizing spray gun.

[0021] Preferably, the external economizer can reduce the flue gas temperature to 90-150°C.

[0022] The present invention also provides a control method for a flue gas purification device in which a calcium-based absorbent and a sodium-based absorbent cooperate, comprising a calcium-based absorbent control subroutine and a sodium-based absorbent control subroutine.

[0023] The calcium-based absorbent control subroutine includes the following steps:

[0024] 1) Calculate the critical cycle calcium-based absorbent addition amount Crit_Ca_Recycle and proceed to step 2;

[0025] 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.

[0026] 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. If the judgment result is "yes", execute step 3; if the judgment result is "no", execute step 8;

[0027] 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 , can be determined through field tests; a=0.4~0.6.

[0028] 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.

[0029] 4) Set the amount of calcium-based absorbent added to the cycle to be equal to the critical calcium-based absorbent addition amount Crit_Ca_Recycle.

[0030] 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;

[0031] Among them, Crit_Ca_Sorbent can be calculated as follows:

[0032]

[0033] Where: Crit_Ca_NSR is the critical calcium-acid molar ratio, ranging from 2.0 to 4.0; Purity_Ca is the purity of fresh calcium-based absorbent.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 9) Determine whether the amount of circulating calcium-based absorbent added is greater than zero. If the determination result is "yes", execute step 11; if the determination result is "no", execute step 1.

[0038] 10) Reduce the amount of fresh calcium-based absorbent added. Preferably, use PID regulation to adjust it.

[0039] 11) Reduce the amount of circulating calcium-based absorbent added. Preferably, use PID regulation to adjust it.

[0040] 12) Increase the amount of circulating calcium-based absorbent added, preferably using PID regulation.

[0041] 13) Increase the amount of fresh calcium-based absorbent added, preferably using PID regulation.

[0042] The sodium-based absorbent control subroutine includes the following steps:

[0043] 1) Calculate the present value of the sodium-acid molar ratio PV_Na_NSR;

[0044] Among them, PV_Na_NSR can be calculated as follows:

[0045]

[0046] Where: PV_Na_Sorbent is the present value of the amount of sodium-based absorbent added, which can be measured by the sodium-based absorbent weighing device and is expressed in 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.

[0047] 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.

[0048] 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. If the judgment result is "yes", execute step 4; if the judgment result is "no", execute step 7;

[0049] Among them, Crit_Na_NSR=1.1~1.8.

[0050] 4) Determine whether the present value of the dry deacidification tower operating differential pressure PV_DP_Scrubber is less than the set critical dry deacidification tower operating differential pressure Crit_DP_Scrubber. If the judgment result is "yes", execute step 5; if the judgment result is "no", execute step 7;

[0051] PV_DP_Scrubber is calculated from the pressure values measured by the inlet and outlet pressure transmitters of the dry deacidification tower, and the unit is Pa; Crit_DP_Scrubber = 500~1500Pa.

[0052] 5) Increase the amount of sodium-based circulating ash added, preferably using PID regulation.

[0053] 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.

[0054] 7) Increase the amount of sodium-based absorbent added, preferably using PID regulation.

[0055] 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.

[0056] 9) Reduce the amount of sodium-based absorbent added. Preferably, use PID regulation.

[0057] 10) Reduce the amount of sodium-based circulating ash added, preferably using PID regulation.

[0058] Compared with the prior art, the flue gas purification device and control method of the present invention using a calcium-based absorbent and a sodium-based absorbent in combination have at least the following beneficial effects:

[0059] (1) The present invention provides a flue gas purification device and control method that cooperates with a calcium-based absorbent and a sodium-based absorbent. The calcium-based absorbent is sprayed into the area where the flue gas temperature of the incinerator is 350~550℃ for primary deacidification, replacing the need for a separate primary deacidification tower, reducing the floor space, and being suitable for projects with relatively compact layouts. 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 smoke and air system can be reduced, thereby improving the economic benefits of the project.

[0060] (2) According to the provisions of the "Technical Standard for the Incineration and Energy Utilization of Municipal Waste" (GB / T51452-2024), boiler ash refers to "solid matter discharged from the lower part of the heating surface of the incineration boiler" and fly ash refers to "powdery solid matter discharged from the flue gas purification system, including ash discharged from the reaction tower, dust collector, flue and chimney bottom". According to the provisions of the "Technical Standard for the Solidification and Stabilization of Fly Ash from Municipal Waste Incineration", "the collection, storage and transportation of fly ash should comply with the relevant provisions of the current industry standard "Technical Specification for the Collection, Storage and Transportation of Hazardous Waste" HJ 2025". Therefore, the disposal cost of fly ash is much higher than the disposal cost 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, the present invention sprays the calcium-based absorbent in the area where the flue gas temperature of the incinerator is suitable, and the injected calcium-based absorbent, reaction products, etc. can be disposed of as boiler ash, which can greatly save the cost of fly ash disposal and improve the economic benefits of the project.

[0061] (3) Conventional economizer ash hoppers remove ash by reducing the flue gas flow rate and allowing it to settle naturally, resulting in poor ash removal efficiency. The present invention provides a pre-dust hopper to increase the flue gas flow rate. First, the ash is concentrated by centrifugal separation for primary separation. Second, a dust removal element group is provided in the pre-dust hopper to perform secondary separation on the ash in the flue gas. This significantly improves the economizer ash hopper's dust removal efficiency and reduces fly ash disposal costs.

[0062] (4) The present invention recycles the fly ash collected by the pre-dust removal hopper as a deacidifying agent, making full use of the calcium-based absorbent. At the same time, due to the recycling of the fly ash collected by the pre-dust removal hopper, the content of the absorbent in the incinerator is greatly increased, the deacidification efficiency of the calcium-based deacidification process is improved, the use of the sodium-based deacidifying agent can be reduced, and the economic benefits of the project are improved.

[0063] (5) The present invention grinds the fly ash collected by the pre-dust removal 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 acid gas, thereby improving the deacidification effect and the utilization rate of the slaked lime.

[0064] The flue gas purification device and control method using a calcium-based absorbent and a sodium-based absorbent in combination with each other according to the present invention will be further described below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] Figure 1 This is a schematic diagram of a flue gas purification device in which a calcium-based absorbent and a sodium-based absorbent cooperate with each other according to the present invention.

[0066] Figure 2 It is a cross-sectional diagram of the pre-dust removal hopper.

[0067] Figure 3 for Figure 2 AA view in .

[0068] Figure 4 This is a schematic diagram of the dimensions of the pre-dust hopper.

[0069] Figure 5 Schematic diagram of the dust removal element group in the pre-dust hopper.

[0070] Figure 6 Schematic diagram of the dimensions of the dust removal component.

[0071] Figure 7 It is a three-dimensional schematic diagram of the dust removal component.

[0072] Figure 8 A side view of the dust removal element.

[0073] Figure 9 The present invention is a logic diagram of a calcium-based absorbent control subroutine of a flue gas purification device in which a calcium-based absorbent and a sodium-based absorbent are coordinated.

[0074] Figure 10 The present invention is a logic diagram of the sodium-based absorbent control subroutine of a flue gas purification device in which a calcium-based absorbent and a sodium-based absorbent are coordinated.

[0075] Among them, 1-incinerator, 2-transition flue, 3-pre-dust hopper; 4-dry deacidification tower, 5-dust and saltpeter integrated device, 6-external economizer, 7-induced draft fan, 8-chimney, 9-calcium-based absorbent coarse powder bin, 10-calcium-based absorbent coarse powder bin metering feeding device, 11-calcium-based absorbent grinder, 12-circulating calcium-based absorbent fine powder collection device, 13-calcium-based absorbent grinder powder conveying fan, 14-circulating calcium-based absorbent metering weighing device, 15-circulating calcium-based absorbent powder conveying ejector, 16-circulating calcium-based absorbent powder conveying fan, 17-calcium-based circulating ash bin, 18-calcium-based circulating ash bin metering feeding device, 19-sodium-based absorbent coarse powder bin, 20-sodium-based Absorbent grinder, 21-sodium-based absorbent fine powder collection device, 22-sodium-based absorbent grinder powder conveying fan, 23-sodium-based absorbent coarse powder silo metering feeding device, 24-sodium-based absorbent powder conveying injector, 25-sodium-based absorbent powder conveying fan, 26-ammonia storage tank, 27-ammonia delivery pump, 28-ammonia atomizing spray gun, 29-activated carbon storage silo, 30-activated carbon metering feeding device, 31-activated carbon powder conveying injector, 32-activated carbon powder conveying fan, 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;

[0076] 301 - pre-dust 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 plate, 309 - ash discharge port, 310 - pre-dust hopper flue gas outlet, 311 - second side wall panel;

[0077] 3071-side panel, 3072-windward panel, 3073-partition panel, 3074-wind blocking panel. DETAILED DESCRIPTION

[0078] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0079] The basic design parameters of this embodiment are shown in the following table:

[0080]

[0081] like Figure 1-8 As shown, a flue gas purification device that uses a combination of calcium-based and sodium-based absorbents comprises an incinerator 1, a transition flue 2, a pre-dust hopper 3, a dry deacidification tower 4, an integrated dust and nitrate device 5, an external economizer 6, an induced draft fan 7, and a chimney 8, all connected in sequence via a flue. The incinerator 1 is connected to a calcium-based absorbent injection system, which uses slaked lime. The dry deacidification tower 4 is connected to a sodium-based absorbent injection system, which uses baking soda. The dry deacidification tower 4 is also connected to an activated carbon injection system. The integrated dust and nitrate device 5 is a device equipped with a catalytic filter element, which is a catalytic filter bag, capable of removing dust and nitrogen oxides. (If needed, the integrated dust and nitrate device described in "A Dry-Process Multi-Pollutant Flue Gas Purification Device and Method" (CN116651168B) may be used.) The inlet of the integrated dust and nitrate device 5 is connected to an SCR reducing agent preparation system, which uses aqueous ammonia. A first CEMS 34 is provided at the inlet of the dry deacidification tower 4 , a second CEMS 35 is provided at the inlet of the chimney 8 , and an inlet pressure transmitter 36 and an outlet pressure transmitter 37 are provided at the inlet and outlet of the dry deacidification tower 4 respectively.

[0082] The pre-dust hopper 3 consists of an upper wall panel 305, a first lower wall panel 302, a second lower wall panel 303, a first side wall panel 306, two second side wall panels 311, an ash storage hopper 304, and a partition panel 308. The lower portion of the upper wall panel 305 is a semicircular concave arc plate, and the upper portion is a vertical plate, which is connected to the upper edge of one side of the semicircular concave arc plate; the radius of the semicircular concave arc plate is c = 1100mm. The first lower wall panel 302 is a concave arc plate, and the arc surface of the first lower wall panel 302 is concentric with the arc surface of the upper wall panel 305. The radius e of the first lower wall panel 302 is the sum of the radius c of the upper wall panel 305 and the outlet width a = 1100mm of the transition flue 2, that is, e = c + a = 2200mm. The central angle of the first lower wall panel 302 is 90°. The second lower wall panel 303 is a convex arc plate. The first lower wall panel 302 and the second lower wall panel 303 are connected and tangent at the connection. The radius of the second lower wall panel 303 is equal to the radius of the upper wall panel, c = 1100mm, and the central angle of the second lower wall panel 303 is 90°. The pre-dust hopper flue gas inlet 301 is formed between the upper edge of one side of the upper wall panel 305 and the upper edge of the first lower wall panel 302; the pre-dust hopper flue gas outlet 310 is formed between the upper edge of the other side of the upper wall panel 305 and the upper edge of the first side wall panel 306. The outlet width of the transition flue 2 is equal to the width of the pre-dust hopper flue gas inlet 301 and the pre-dust hopper flue gas outlet 310, both of which are a = 1100mm. The width between the second lower wall panel 303 and the first side wall panel 306 is a = 1100mm.

[0083] The isolation plate 308 is located inside the pre-dust hopper 3 and is a concave arc plate. The arc surface of the isolation plate 308 is parallel to the arc surface of the upper wall panel 305. The radius of the isolation plate 308 is equal to the radius e = 2200mm of the first lower wall panel 302. The minimum distance f = 330mm between the isolation plate 308 and the first lower wall panel 302. The leading end of the isolation plate 308 and the trailing end of the first lower wall panel 302 are in the same vertical plane, and the trailing end of the isolation plate 308 is connected to the inner wall surface of the first side wall panel 306. The isolation plate 308 has a vent hole near the first side wall panel 306. The vent hole is a strip hole with a width equal to the width of the transition flue outlet a = 1100mm and a length d = 550mm. An ash storage hopper 304 is located at the lowest point of the pre-dust hopper 3, connected to the lower edge of the second lower wall panel 303 and the lower edge of the first side wall panel 306. The two second sidewall panels 311 are located on the front and rear sides of the pre-dust hopper 3, respectively, and are connected to the front and rear edges of the upper wall panel 305, the first lower wall panel 302, the second lower wall panel 303, and the first sidewall panel 306. An ash discharge port 309 is provided at the bottom of the ash storage hopper 304. This ash discharge port 309 is connected to the inlet of the calcium-based circulating ash bin 17 and the calcium-based circulating ash discharge line 38, respectively.

[0084] The cross-section of the transition flue 2 is a right-angled trapezoid, and the flow area gradually decreases along the direction of the flue gas flow, that is, the outer wall panel of the transition flue 2 connecting the transition flue 2 and the first lower wall panel 302 of the pre-dust hopper 3 is vertically downward, and the inner wall panel of the transition flue connected to the upper wall panel 305 of the pre-dust hopper 3 is inclined toward the outer wall panel of the transition flue, so that the flue gas flow rate gradually increases, ensuring that the outlet flue gas flow rate of the transition flue 2 is between 10 and 15 m / s, and the angle formed by the outer wall panel of the transition flue and the inner wall panel of the transition flue is 30°, the outlet width of the transition flue is 1100 mm, and the length is 3000 mm.

[0085] The pre-dust hopper 3 houses a dust removal assembly consisting of three dust removal elements 307. The dust removal element 307 comprises two side panels 3071, a windward panel 3072, a partition 3073, and a wind blocking panel 3074. The two side panels 3071 and the windward panel 3072 form a groove structure with an isosceles trapezoidal cross-section. The groove structure opens toward the flue gas inflow direction, and the angle β formed by the two side panels 3071 is 60°. The groove structure has an opening width g = 200 mm and a depth s = 400 mm. The partition 3072 is vertically positioned at the center of the groove structure and perpendicularly connected to the windward panel 3072. The height u of the partition 3073 is 320 mm. The upper portion of the dust removal element 307 is fixed to the upper wall panel 305 of the pre-dust hopper 3, while the lower portion passes through the partition panel 308, leaving a gap between it and the second lower wall panel 303. The air blocking plate 3074 encloses the groove structure below the isolation plate 308. Specifically, the front and rear edges of the air blocking plate 3074 are connected to the edges of the two side panels 3071 below the isolation plate 308. The spacing h between adjacent dust removal elements 307 in the same row is 500 mm. The dust removal elements in adjacent rows are staggered, with a spacing k of 400 mm between the elements in each row.

[0086] The length of each dust removal element tends to increase along the direction of flue gas flow, that is, to ensure that the bottom of the latter dust removal element is lower than the bottom of the former dust removal element, so as to avoid the flue gas being sucked into the dust removal element and causing the dust removal effect to be reduced.

[0087] The calcium-based absorbent injection system includes 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 (the calcium-based absorbent grinder powder conveying fan forms a negative pressure in the grinding chamber of the calcium-based absorbent grinder and in the circulating calcium-based absorbent fine powder collecting device, and the material in the grinder is sucked into the fine powder collecting device for collection), 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.

[0088] Among them, the outlet of the calcium-based absorbent coarse powder bin 9 is connected to the calcium-based absorbent coarse powder bin metering feeding device 10, the outlet of the calcium-based circulating ash bin 17 is connected to the calcium-based circulating ash bin metering feeding device 18, the calcium-based absorbent coarse powder bin metering feeding device 10 and the calcium-based circulating ash bin metering feeding device 18 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 circulating calcium-based absorbent fine powder collecting device 12, the upper outlet of the circulating calcium-based absorbent fine powder collecting device 12 is connected to the calcium-based absorbent grinder powder conveying fan 13, the lower outlet of the circulating calcium-based absorbent fine powder collecting device 12 is connected to the circulating calcium-based absorbent metering weighing device 14, the outlet of the circulating calcium-based absorbent metering weighing device 14 and the circulating calcium-based absorbent powder conveying fan 16 are both connected to the circulating calcium-based absorbent powder conveying injector 15, and the outlet of the circulating calcium-based absorbent powder conveying injector 15 is connected to the incinerator 1.

[0089] The sodium-based absorbent injection system includes 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 powder conveying fan 25, and a sodium-based absorbent powder conveying injector 24.

[0090] Among them, the sodium-based absorbent coarse powder bin 19, the sodium-based absorbent grinder 20, and the sodium-based absorbent fine powder collecting device 21 are connected in sequence, the upper outlet of the sodium-based absorbent fine powder collecting device 21 is connected to the sodium-based absorbent grinder powder conveying fan 22, the lower outlet of the sodium-based absorbent fine powder collecting device 21 is connected to the sodium-based absorbent coarse powder bin metering feeding device 23, the outlet of the sodium-based absorbent coarse powder bin metering feeding device 23 and the sodium-based absorbent powder conveying fan 25 are both connected to the sodium-based absorbent powder conveying injector 24, and the outlet of the sodium-based absorbent powder conveying injector 24 is connected to the upper inlet of the dry deacidification tower 4.

[0091] The calcium-based absorbent coarse powder bin metering feeder 10 and the calcium-based circulating ash bin metering feeder 18 feature remote adjustment capabilities, respectively controlling the amount of calcium-based absorbent coarse powder and calcium-based circulating ash entering the calcium-based absorbent grinder 11. The calcium-based absorbent grinder 11 features remote adjustment capabilities to control the particle size of the absorbent at its outlet (D90 ≤ 10μm), and an air classifying mill is used. The metering feeders utilize a loss-in-weight scale with remote adjustment capabilities. The circulating calcium-based absorbent metering weighing device 14 also features remote adjustment capabilities to control the amount of calcium-based absorbent injected into the incinerator as needed.

[0092] The activated carbon injection system includes an activated carbon storage bin 29, an activated carbon metering feeder 30, an activated carbon powder ejector 31, and an activated carbon powder conveying fan 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 conveying fan are both connected to the activated carbon powder ejector 31. The outlet of the activated carbon powder ejector 31 is connected to the sidewall inlet of the dry deacidification tower 4.

[0093] 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 connected in sequence. The ammonia water in the ammonia water storage tank 26 is transported to the flue at the entrance of the dust and saltpeter integrated device 5 by the ammonia water delivery pump 27 and the ammonia water atomizing spray gun 28.

[0094] The lower outlet of the dust and saltpeter integrated device 5 is connected to the sodium-based circulating ash return screw conveyor 33, and the sodium-based circulating ash return screw conveyor 33 is connected to the side wall inlet of the dry deacidification tower 4.

[0095] The above-mentioned flue gas purification device in which the calcium-based absorbent and the sodium-based absorbent are coordinated is used in a flue gas purification project. The control method of the flue gas purification device in which the calcium-based absorbent and the sodium-based absorbent are coordinated is combined with Figure 9 、 Figure 10 As shown, the following steps are included:

[0096] When the flue gas purification device with calcium-based absorbent and sodium-based absorbent is put into operation, the calcium-based deacidification is controlled by the calcium-based absorbent control subroutine:

[0097] 1) Calculate the critical cycle calcium-based absorbent addition amount Crit_Ca_Recycle and proceed to step 2;

[0098] Among them, Crit_Ca_Recycle=Crit_k_Recycle×Gas_Flow÷1000=3000kg / h, unit is kg / h, and the recycling coefficient of the circulating calcium-based absorbent Crit_k_Recycle=30, unit is g / Nm 3 , Gas_Flow=100000Nm 3 / h, is the flue gas flow rate measured by the first CEMS, in Nm 3 / h.

[0099] 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. If the judgment result is "yes", execute step 3; if the judgment result is "no", execute step 8;

[0100] 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 original flue gas, Raw_SO2=500 is the average concentration of SO2 in the original flue gas, the unit is mg / Nm 3 ;a=0.6.

[0101] 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 = 3000 kg / h. When the judgment result is "yes", execute step 4; when the judgment result is "no", execute step 12.

[0102] 4) Set the amount of recycled calcium-based absorbent added to be equal to the critical amount of recycled calcium-based absorbent added Crit_Ca_Recycle = 3000kg / h.

[0103] 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;

[0104] Among them, Crit_Ca_Sorbent can be calculated as follows:

[0105]

[0106]

[0107] Where: Crit_Ca_NSR is the critical calcium-acid molar ratio, which is 3.0; Purity_Ca is the purity of fresh calcium-based absorbent, which is 90%.

[0108] 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.

[0109] 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.

[0110] 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.

[0111] 9) Determine whether the amount of circulating calcium-based absorbent added is greater than zero. If the determination result is "yes", execute step 11; if the determination result is "no", execute step 1.

[0112] 10) Reduce the amount of fresh calcium-based absorbent added and use PID regulation.

[0113] 11) Reduce the amount of circulating calcium-based absorbent added and use PID regulation.

[0114] 12) Increase the amount of circulating calcium-based absorbent and adjust it using PID regulation.

[0115] 13) Increase the amount of fresh calcium-based absorbent and adjust it using PID regulation.

[0116] The sodium-based absorbent control subroutine includes the following steps:

[0117] 1) Calculate the present value of the sodium-acid molar ratio PV_Na_NSR;

[0118] Among them, PV_Na_NSR can be calculated as follows:

[0119]

[0120] Where: PV_Na_Sorbent is the present value of the amount of sodium-based absorbent added, which can be measured by the sodium-based absorbent weighing device and is expressed in 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.

[0121] 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.

[0122] 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. If the judgment result is "yes", execute step 4; if the judgment result is "no", execute step 7;

[0123] Among them, Crit_Na_NSR=1.3.

[0124] 4) Determine whether the present value of the dry deacidification tower operating differential pressure PV_DP_Scrubber is less than the set critical dry deacidification tower operating differential pressure Crit_DP_Scrubber. If the judgment result is "yes", execute step 5; if the judgment result is "no", execute step 7;

[0125] PV_DP_Scrubber is calculated from the pressure values measured by the inlet and outlet pressure transmitters of the dry deacidification tower, and the unit is Pa; Crit_DP_Scrubber = 800Pa.

[0126] 5) Increase the amount of sodium-based circulating ash added and use PID regulation to adjust it.

[0127] 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.

[0128] 7) Increase the amount of sodium-based absorbent and adjust it using PID regulation.

[0129] 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.

[0130] 9) Reduce the amount of sodium-based absorbent added and use PID regulation.

[0131] 10) Reduce the amount of sodium-based circulating ash added and use PID regulation.

[0132] The embodiments described above are merely descriptions of preferred implementations of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should fall within the scope of protection determined by the claims of the present invention.

Claims

1. A control method for a flue gas purification device using a calcium-based absorbent and a sodium-based absorbent, characterized in that: The flue gas purification device comprises an incinerator (1), a transition flue (2), a pre-dust removal 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 sequentially connected 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 further provided with an inlet pressure transmitter (36) and an outlet pressure transmitter (37), respectively; The control method includes a calcium-based absorbent control subroutine, and the calcium-based absorbent control subroutine includes the following steps: 1) Calculate the critical cycle calcium-based absorbent addition amount Crit_Ca_Recycle and proceed to 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. If the judgment result is "yes", execute step 3; if 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. If the judgment result is "yes", execute step 4; if the judgment result is "no", execute step 12; 4) Set the amount of calcium-based absorbent added to the cycle to be equal to the critical calcium-based absorbent addition amount 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 judgment result is "yes", execute step 6; if the judgment 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 terminate the calcium-based absorbent automatic control subroutine. If the determination result is "yes", terminate the automatic control. If the determination 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. If the determination result is "yes", execute step 11; if the determination 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.

2. The control method of 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 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, in 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. If the judgment result is "yes", execute step 3; if 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. If the judgment result is "yes", execute step 4; if the judgment result is "no", execute step 7; Among them, Crit_Na_NSR=1.1~1.8; 4) Determine whether the present value of the dry deacidification tower operating differential pressure PV_DP_Scrubber is less than the set critical dry deacidification tower operating differential pressure Crit_DP_Scrubber. If the judgment result is "yes", execute step 5; if the judgment result is "no", execute step 7; Where 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 terminate the sodium-based absorbent automatic control subroutine. If the determination result is "yes", terminate the automatic control. If the determination result is "no", execute step 1. 7) Increase the amount of sodium-based absorbent 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. If the judgment result is "yes", execute step 9; if 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 regulation.

3. The control method of the flue gas purification device using a calcium-based absorbent and a sodium-based absorbent according to claim 1 or 2, 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 an isolation plate (308); The lower portion of the upper wall plate (305) is a semicircular concave arc plate, and the upper portion 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). The central angle of the first lower wall plate (302) 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. 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, and the tail end of the isolation plate (308) is connected to the first side wall plate (306). 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 flue gas flow direction, and the angle formed by the outer wall plate of the transition flue and the inner wall plate of the transition flue is no more than 30°.

4. The control method of the flue gas purification device using a calcium-based absorbent and a sodium-based absorbent in cooperation with each other according to claim 1 or 2, characterized in that: A dust removal element group is provided in the pre-dust removal hopper (3), and the dust removal element group includes at least two 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 trapezoidal cross section, and the opening of the groove structure faces 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). The wind blocking plate (3074) closes the groove structure below the isolation plate (308).

5. 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 claim 4, 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.

6. The control method of the flue gas purification device using a calcium-based absorbent and a sodium-based absorbent in cooperation with each other according to claim 1 or 2, 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).

7. The control method of the flue gas purification device using a calcium-based absorbent and a sodium-based absorbent in cooperation with each other according to claim 1 or 2, 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 powder conveying fan (25), and a sodium-based absorbent powder conveying injector (24).

8. The control method of the flue gas purification device using a calcium-based absorbent and a sodium-based absorbent in cooperation with each other according to claim 1 or 2, characterized in that: The activated carbon injection system includes an activated carbon storage bin (29), an activated carbon metering feeding device (30), an activated carbon powder feeding injector (31), and an activated carbon powder feeding fan (32); The dust and saltpeter integrated device (5) is a device with a catalytic filter element installed inside, which has the function of removing dust and nitrogen oxides. The catalytic filter element is a catalytic filter bag or a catalytic ceramic filter tube.

9. The control method of the flue gas purification device using a calcium-based absorbent and a sodium-based absorbent in cooperation with each other according to claim 1 or 2, 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.

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