Additive spraying device system based on alkali metal concentration field gradient attenuation control

Abstract

The invention provides an additive injection device system based on alkali metal concentration field gradient attenuation control. The additive injection device system comprises an alkali metal concentration measuring module and an additive injection module. The alkali metal concentration measurement module is arranged in a main combustor area and a reduction area in a hearth; the additive spraying module comprises an additive spraying opening and an additive conveying device which are connected in sequence; and the additive jet orifice and the alkali metal concentration measurement module are arranged at the same height. The alkali metal concentration measuring module and the additive spraying module are arranged at specific positions, so that alkali metal in flue gas is accurately captured, condensation and deposition of the alkali metal are inhibited, and safe, stable and long-period operation of a unit is guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of boiler optimized operation, and in particular to an additive injection device system based on alkali metal concentration field gradient attenuation control. Background Art

[0002] To reduce fuel costs, coal-fired power generation companies are blending high-alkali coal (Na2O content in the ash >3% by weight) with the designated coal type. The Na2O and CaO contents in the ash of high-alkali coal can reach 3-10% by weight and 20-40% by weight, respectively. This high proportion of Xinjiang high-alkali coal leads to severe ash deposition during combustion. Current technologies for controlling high-alkali coal ash deposition primarily include blended coal combustion, combustion optimization, the addition of additives, and heat exchange surface material modification.

[0003] Currently, the most commonly used additives are kaolin and vermiculite, which are primarily conveyed through a belt blender into the pulverizer and then fed into the furnace along with the pulverized coal. This method of blending is simple, with a relatively fixed additive ratio, but carries the risk of over- or under-blending.

[0004] CN118935437A discloses a system and method for mixing kaolin with a high-alkali coal-fired boiler, comprising a coal bunker, a coal conveyor belt, a coal mill, a kaolin bunker, a kaolin conveyor belt, a kaolin mill, a primary fan, a coal conveyor air duct, a coal conveyor air valve, a coal-air-powder pipeline, a venturi ejector, a burner, a kaolin conveyor air duct, a kaolin conveyor air valve, an air mixing chamber, a temperature sensor, a circulating fan, a circulating flue gas pipeline, a circulating flue gas valve, a kaolin-air-powder pipeline, a boiler, The screen superheater, superheater, reheater, economizer, SCR catalyst layer, and air preheater are equipped with a separate grinding device for kaolin to reduce the kaolin particle size, increase the kaolin specific surface area, and improve the capture efficiency of gas-phase alkali metals. The venturi ejector device is used to add kaolin to the second-layer burner nozzle to avoid affecting the combustion condition of the boiler when adding the lower layer and incomplete reaction of kaolin when adding the upper layer. At the same time, the circulating flue gas is used to heat the kaolin to ensure stable combustion of the boiler.

[0005] CN118293437A discloses a pulverized coal anti-slagging combustion system, comprising: a boiler having a furnace for burning pulverized coal, the furnace being provided with an adsorbent nozzle; and a supply device connected to the adsorbent nozzle and supplying an anti-slagging adsorbent, so that the anti-slagging adsorbent is sprayed into the furnace through the adsorbent nozzle. By providing the adsorbent nozzle in the furnace, and the supply device being connected to the adsorbent nozzle and supplying the anti-slagging adsorbent, the anti-slagging adsorbent is sprayed into the center of the flame or the surrounding space. The anti-slagging adsorbent can fully absorb sodium vapor, is more targeted, improves the utilization rate of the anti-slagging adsorbent, avoids waste of the anti-slagging adsorbent, and improves the slagging phenomenon on the inner wall of the furnace.

[0006] While the above-mentioned pulverized coal blending system reduces the risk of coking on the heating surface, it also brings about problems such as reduced mill output and wear of the heating surface. Summary of the Invention

[0007] In view of the problems existing in the prior art, the present invention provides an additive injection device system based on alkali metal concentration field gradient attenuation control. By setting an alkali metal concentration measurement module and an additive injection module at specific positions, additives are used to accurately capture alkali metals in the flue gas, inhibit the condensation and deposition of alkali metals, and ensure safe and stable operation of the unit.

[0008] To achieve this object, the present invention adopts the following technical solutions:

[0009] In a first aspect, the present invention provides an additive injection device system based on alkali metal concentration field gradient attenuation control, the additive injection device system comprising an alkali metal concentration measurement module and an additive injection module;

[0010] The alkali metal concentration measurement module is arranged in the main burner area and the reduction area inside the furnace; the additive injection module includes an additive injection port and an additive delivery device connected in sequence; the additive injection port and the alkali metal concentration measurement module are arranged at the same height.

[0011] The additive injection device system based on alkali metal concentration field gradient attenuation control described in the present invention is aimed at units burning high-alkali coal. The alkali metal concentration measurement module and the additive injection module are reasonably set. Based on the principle of alkali metal concentration field gradient attenuation, the injection position and injection amount of the additive are controlled to achieve accurate and precise capture of alkali metals in flue gas, inhibit the condensation and deposition of alkali metals, inhibit coking on the boiler heating surface, and realize long-term safe and stable combustion of high-alkali coal.

[0012] The present invention does not impose any specific restrictions on the measurement method adopted by the alkali metal concentration measurement module, and laser induced plasma spectroscopy (LIPS), laser method or X-ray fluorescence spectrometry (XRF) can be flexibly selected.

[0013] Preferably, the main burner area is divided into two parts; the arrangement elevation of the alkali metal concentration measurement module arranged in the main burner area is 0.6 to 0.9 m higher than the elevation of the corresponding burner in each part, for example, it can be 0.6 m, 0.63 m, 0.65 m, 0.7 m, 0.75 m, 0.8 m or 0.9 m, etc., but is not limited to the listed values, and other unlisted values within this numerical range are also applicable.

[0014] Preferably, the arrangement elevation of the alkali metal concentration measurement module arranged in the reduction area is 0.3 to 0.5 m higher than the elevation of the corresponding burner, for example, it can be 0.3 m, 0.33 m, 0.35 m, 0.4 m, 0.45 m or 0.5 m, etc., but is not limited to the listed values, and other unlisted values within this numerical range are also applicable.

[0015] Preferably, 2 to 3 alkali metal concentration measuring devices are provided on the four water-cooled walls of each part of the main burner area, for example, 2 or 3.

[0016] Preferably, 2 to 3 alkali metal concentration measuring devices are provided on each of the four water-cooled walls of the reduction zone, for example, 2 or 3.

[0017] Preferably, on the same water-cooled wall, the alkali metal concentration measuring devices are evenly arranged along the width of the furnace according to the number of arrangements, and the distance between adjacent alkali metal concentration measuring devices is 0.3 to 0.4 times the width of the furnace, for example, it can be 0.3 times, 0.32 times, 0.35 times, 0.37 times, 0.39 times or 0.4 times, etc., but is not limited to the listed values, and other unlisted values within this numerical range are also applicable.

[0018] The present invention preferably arranges alkali metal concentration measuring devices uniformly along the width of the furnace on the same water-cooled wall according to the number of arrangements, and the distance between adjacent alkali metal concentration measuring devices is 0.3 to 0.4 times the width of the furnace, fully taking into account the release of alkali metals during combustion and the ignition and burnout distance of the pulverized coal airflow.

[0019] Preferably, 1 to 2 additive injection ports are provided on the four water-cooled walls of each part of the main burner area, for example, 1 or 2.

[0020] Preferably, 1 to 2 additive injection ports are provided on each of the four water-cooled walls of the reduction zone, for example, 1 or 2.

[0021] Preferably, each additive injection port is connected to an independent additive delivery device.

[0022] The additive injection module of the present invention further comprises an additive storage device and an additive crushing device sequentially connected to the additive delivery device; the additive delivery device is connected to the hot primary air duct; the additive delivery device is connected to the additive injection port via the additive delivery duct.

[0023] Preferably, on the same water-cooled wall, the distance between the additive injection port and the adjacent alkali metal concentration measuring device is 3 to 5 m, for example, 3 m, 3.2 m, 3.5 m, 3.8 m, 4 m or 5 m, etc., but is not limited to the listed values, and other values not listed within the numerical range are also applicable;

[0024] Preferably, on the same water-cooled wall, the angle between the center line of the additive injection port and the water-cooled wall surface is 50° to 60°, for example, it can be 50°, 52°, 54°, 55°, 57°, 58° or 60°, etc., but is not limited to the listed values, and other unlisted values within this numerical range are also applicable.

[0025] In a second aspect, the present invention further provides a method for using the additive injection device system based on alkali metal concentration field gradient attenuation control as described in the first aspect, the method comprising:

[0026] When the alkali metal concentration in the flue gas measured by the alkali metal concentration measurement module and the alkali metal theoretical concentration C0 do not meet the constraint conditions, the additive injection module injects additives into the corresponding area inside the furnace;

[0027] The constraints include:

[0028] The average measured value C of the alkali metal concentration in the A layer of the main burner area A ≤0.613C0;

[0029] The average measured value C of the alkali metal concentration in the main burner area B layer B ≤0.486C0;

[0030] The average measured value C of the alkali metal concentration in the reduction zone C layer C ≤0.2C0.

[0031] The method for using the additive injection device system based on alkali metal concentration field gradient attenuation control provided by the present invention is simple to operate. According to the alkali metal field concentration gradient attenuation principle, reasonable constraint conditions are set. By comparing the difference between the alkali metal concentration in the flue gas measured by the alkali metal concentration measurement module and the theoretical alkali metal concentration, the appropriate additive injection position and injection amount are obtained, the alkali metal in the flue gas is accurately captured, the coking of the boiler heating surface is suppressed, and the long-term safe and stable operation of the unit burning high-alkali coal is achieved.

[0032] Preferably, the calculation formula of the theoretical alkali metal concentration C0 is:

[0033] C0=W 煤 ×A×C Na+K +Q 理论烟气量

[0034] Among them, W 煤is the coal feeding rate, t / h; A is the mass percentage of ash, wt%; C Na+K is the alkali metal content in coal ash, wt%; Q 理论烟气量 is the theoretical flue gas volume, t / h.

[0035] Preferably, the injection amount of the additive is calculated by the following formula:

[0036] Q A =(0.613C0-C A )×Q A烟气量 ×α

[0037] Q B =(0.486C0-C A )×Q B烟气量 ×α

[0038] Q C =(0.2C0-C A )×Q C烟气量 ×α

[0039] Among them, Q A The additive amount of the main burner area A layer, kg; Q A烟气量 The flue gas volume corresponding to all coal fed into the upstream of the additive nozzle in layer A of the main burner area, t / h;

[0040] Q B The additive amount of the main burner area B layer, kg; Q B烟气量 The flue gas volume corresponding to all coal fed into the upstream of the additive nozzle in the B layer of the main burner area, t / h;

[0041] Q C Q is the additive amount of the reduction zone C layer, kg; C烟气量 is the flue gas volume corresponding to all coal fed into the furnace upstream of the additive nozzle in the C layer of the reduction area, t / h;

[0042] α is the additive correlation coefficient, and the value for kaolin is 11.28 to 13.57, for example, it can be 11.28, 11.5, 12, 12.5, 13 or 12.57, etc., but it is not limited to the listed values, and other values not listed within the numerical range are also applicable.

[0043] Preferably, the fineness R90 of the additive is 8% to 12%, for example, it can be 8%, 8.5%, 9%, 9.5%, 10%, 11% or 12%, etc., but is not limited to the listed values, and other unlisted values within the numerical range are also applicable.

[0044] Preferably, the powder feeding speed of the additive is 22 to 28 m / s, for example, it can be 22 m / s, 23 m / s, 24 m / s, 25 m / s, 26 m / s, 27 m / s or 28 m / s, etc., but is not limited to the listed values, and other unlisted values within this numerical range are also applicable.

[0045] The additive injection module of the present invention can be controlled by a PID controller, that is, the alkali metal concentration x1 in the flue gas measured by the alkali metal concentration measurement module and the alkali metal theoretical concentration C0 constraint x2 are input into the PID controller, and the additive injection amount of the additive injection port corresponding to the additive injection module is determined by the calculation formula f(x).

[0046] As a preferred technical solution of the present invention, the method of use includes:

[0047] When the alkali metal concentration in the flue gas measured by the alkali metal concentration measurement module and the alkali metal theoretical concentration C0 do not meet the constraint conditions, the additive injection module injects additives into the corresponding area inside the furnace;

[0048] The constraints include:

[0049] The average measured value C of the alkali metal concentration in the A layer of the main burner area A ≤0.613C0;

[0050] The average measured value C of the alkali metal concentration in the main burner area B layer B ≤0.486C0;

[0051] The average measured value C of the alkali metal concentration in the reduction zone C layer C ≤0.2C0;

[0052] The calculation formula of the theoretical alkali metal concentration C0 is:

[0053] C0=W 煤 ×A×C Na+K ÷Q 理论烟气量

[0054] Among them, W 煤 is the coal feeding rate, t / h; A is the mass percentage of ash, wt%; C Na+K is the alkali metal content in coal ash, wt%; Q 理论烟气量 is the theoretical flue gas volume, t / h.

[0055] The injection amount of the additive is calculated by the following formula:

[0056] Q A =(0.613C0-C A )×Q A烟气量 ×α

[0057] Q B =(0.486C0-C A )×Q B烟气量 ×α

[0058] Q C =(0.2C0-C A )×Q C烟气量 ×α

[0059] Among them, Q A The additive amount of the main burner area A layer, kg; Q A烟气量 The flue gas volume corresponding to all coal fed into the upstream of the additive nozzle in layer A of the main burner area, t / h;

[0060] Q B The additive amount of the main burner area B layer, kg; Q B烟气量 The flue gas volume corresponding to all coal fed into the upstream of the additive nozzle in the B layer of the main burner area, t / h;

[0061] Q C Q is the additive amount of the reduction zone C layer, kg; C烟气量 is the flue gas volume corresponding to all coal fed into the furnace upstream of the additive nozzle in the C layer of the reduction area, t / h;

[0062] α is the additive correlation coefficient, with values ranging from 11.28 to 13.57 for kaolin;

[0063] The fineness R90 of the additive is 8% to 12%; the powder feeding speed of the additive is 22 to 28 m / s.

[0064] Compared with the prior art, the present invention has at least the following beneficial effects:

[0065] The additive injection device system based on alkali metal concentration field gradient attenuation control provided by the present invention reasonably arranges alkali metal concentration measuring devices and additive injection ports in the main burner area and reduction area inside the furnace, and sets reasonable constraint conditions according to the alkali metal field concentration gradient attenuation principle. By comparing the difference between the measured value of the alkali metal concentration in the flue gas and the theoretical alkali metal concentration value, the appropriate additive injection position and injection amount are obtained, the alkali metals in the flue gas are accurately captured, and the coking of the boiler heating surface is suppressed, thus solving the problem of coking of the heating surface of the unit burning high-alkali coal in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] Figure 1 It is a schematic diagram of the installation of the alkali metal concentration measurement module in a specific embodiment of the present invention.

[0067] Figure 2 It is a connection diagram of the additive injection module and related devices in a specific embodiment of the present invention.

[0068] Figure 3 It is a schematic diagram of the installation of an alkali metal concentration measuring device on the four water-cooled walls of layer A in the main burner area in a specific embodiment of the present invention.

[0069] Figure 4 It is a schematic diagram of the installation of the alkali metal concentration measuring device and the additive injection port on the four water-cooled walls of the A layer in the main burner area in a specific embodiment of the present invention.

[0070] In the figure: 1-first burner; 2-second burner; 3-third burner; 4-furnace; 5-additive crushing device; 6-additive storage device; 7-additive delivery device; 8-additive injection port; 9-hot primary air duct connection; 10-additive delivery duct;

[0071] A-main burner area A layer; B-main burner area B layer; C-reduction area C layer;

[0072] A1, A2, A3, A4, A5, A6, A7, A8 - Alkali metal concentration measuring devices on the four water-cooled walls of layer A in the main burner area;

[0073] A11, A12, A13, A14 - Additive injection ports in layer A of the main burner area. DETAILED DESCRIPTION

[0074] The technical solution of the present invention will be further described below with reference to the accompanying drawings and through specific implementation methods.

[0075] The present invention is further described in detail below. However, the following examples are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention shall be subject to the claims.

[0076] As a specific embodiment of the present invention, there is provided an additive injection device system based on alkali metal concentration field gradient attenuation control, the additive injection device system comprising an alkali metal concentration measurement module and an additive injection module;

[0077] The alkali metal concentration measurement module is set in the main burner area and the reduction area inside the furnace; the main burner area is divided into two parts; the installation diagram of the alkali metal concentration measurement module is as follows Figure 1 shown. Figure 1 In the figure, 1 represents the first burner in the main burner area, 2 represents the second burner in the main burner area, 3 represents the third burner in the reduction area, 4 represents the furnace, and the green dot represents the alkali metal concentration measuring device.

[0078] The connection diagram of the additive injection module and the associated devices is as follows Figure 2The additive injection module comprises an additive injection port 8 and an additive delivery device 7 connected in sequence; each additive injection port 8 is connected to an independent additive delivery device 7;

[0079] The additive injection port 8 is arranged at the same height as the alkali metal concentration measuring module.

[0080] The additive injection module further includes an additive storage device 6 and an additive crushing device 5 which are sequentially connected to an additive delivery device 7 ; the additive delivery device 7 is connected to a hot primary air duct 9 ; and the additive delivery device 7 is connected to an additive injection port 8 via an additive delivery duct 10 .

[0081] The arrangement elevation of the alkali metal concentration measurement module arranged in the main burner area is 0.8 m higher than the elevation of the corresponding burner in each section.

[0082] The arrangement elevation of the alkali metal concentration measurement module arranged in the reduction area is 0.5m higher than the elevation of the corresponding burner.

[0083] Two alkali metal concentration measuring devices are installed on the four water-cooled walls of each part of the main burner area; the installation diagram of the alkali metal concentration measuring device on the four water-cooled walls of the main burner area layer A is as follows Figure 3 As shown, the alkali metal concentration measuring devices are named A1, A2, A3, A4, A5, A6, A7 and A8 respectively.

[0084] Two alkali metal concentration measuring devices are provided on the four water-cooled walls of the reduction area;

[0085] On the same water-cooled wall, the alkali metal concentration measuring devices are evenly arranged along the width of the furnace according to the number of arrangements, and the distance between adjacent alkali metal concentration measuring devices is 0.3 times the width of the furnace.

[0086] Each of the four water-cooled walls of the main burner region is provided with an additive injection port 8; wherein, the installation diagram of the alkali metal concentration measuring device and the additive injection port 8 on the four water-cooled walls of the main burner region layer A is as shown in FIG. Figure 4 As shown, the additive injection ports 8 are respectively named A11, A12, A13 and A14.

[0087] An additive injection port 8 is provided on each of the four water-cooled walls of the reduction zone;

[0088] On the same water-cooled wall, the distance between the additive injection port 8 and the adjacent alkali metal concentration measuring device is 3 m; on the same water-cooled wall, the angle between the center line of the additive injection port 8 and the water-cooled wall surface is 50°.

[0089] As a specific embodiment of the present invention, a method for using the additive injection device system based on alkali metal concentration field gradient attenuation control is also provided, and the method for using the additive injection device system comprises:

[0090] When the alkali metal concentration in the flue gas measured by the alkali metal concentration measurement module and the alkali metal theoretical concentration C0 do not meet the constraint conditions, the additive injection module injects additives into the corresponding area inside the furnace;

[0091] The constraints include:

[0092] The average measured value C of the alkali metal concentration in the A layer of the main burner area A ≤0.613C0;

[0093] The average measured value C of the alkali metal concentration in the main burner area B layer B ≤0.486C0;

[0094] The average measured value C of the alkali metal concentration in the reduction zone C layer C ≤0.2C0;

[0095] The calculation formula of the theoretical alkali metal concentration C0 is:

[0096] C0=W 煤 ×A×C Na+K ÷Q 理论烟气量

[0097] In this specific embodiment, W 煤 is the coal feed rate, specifically 284 t / h; A is the mass percentage of ash, specifically 4.83 wt%; C Na+K is the alkali metal content in the fly ash, specifically 5.01 wt%; Q 理论烟气量 The theoretical flue gas volume is 2488 t / h. The theoretical concentration of alkali metals C0 is calculated to be 0.027%.

[0098] The injection amount of the additive is calculated by the following formula:

[0099] Q A =(0.613C0-C A )×Q A烟气量 ×α

[0100] Q B =(0.486C0-C A )×Q B烟气量 ×α

[0101] Q C =(0.2C0-C A )×Q C烟气量 ×α

[0102] Among them, Q A The additive amount of the main burner area A layer, kg; Q A烟气量 The flue gas volume corresponding to all coal fed into the upstream of the additive nozzle in layer A of the main burner area, t / h;

[0103] Q B The additive amount of the main burner area B layer, kg; Q B烟气量 The flue gas volume corresponding to all coal fed into the upstream of the additive nozzle in the B layer of the main burner area, t / h;

[0104] Q C Q is the additive amount of the reduction zone C layer, kg; C烟气量 is the flue gas volume corresponding to all coal fed into the furnace upstream of the additive nozzle in the C layer of the reduction area, t / h;

[0105] α is the additive correlation coefficient, which is 11.28 for kaolin;

[0106] The fineness R90 of the additive is 12%; the powder feeding speed of the additive is 28 m / s.

[0107] In this embodiment, the average measured value C of the alkali metal concentration in the reduction region C layer is C >0.2C0, the constraint condition is not met, so it is necessary to spray the additive into the C layer of the reduction area. Q is calculated by the formula C =(0.2×0.027%-0.0021%)×2488×11.28=0.926t / h, the additive injection amount of each additive injection port on the four water-cooled walls of the reduction area C layer is 0.2315t / h.

[0108] In summary, the additive injection device system based on alkali metal concentration field gradient attenuation control provided by the present invention obtains the appropriate additive injection position and injection amount by comparing the difference between the measured value of the alkali metal concentration in the flue gas and the theoretical concentration value of the alkali metal, accurately captures the alkali metals in the flue gas, and solves the problem of coking on the heating surface of the unit burning high-alkali coal in the prior art, and is suitable for large-scale promotion and application.

[0109] The applicant declares that the above is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention fall within the scope of protection and disclosure of the present invention.

Claims

1. An additive injection device system based on alkali metal concentration field gradient attenuation control, characterized in that: The additive injection device system includes an alkali metal concentration measurement module and an additive injection module; The alkali metal concentration measurement module is arranged in the main burner area and the reduction area inside the furnace; the additive injection module includes an additive injection port and an additive delivery device connected in sequence; the additive injection port and the alkali metal concentration measurement module are arranged at the same height.

2. The additive injection device system according to claim 1, characterized in that: The main burner area is divided into two parts; the arrangement elevation of the alkali metal concentration measurement module arranged in the main burner area is 0.6 to 0.9 meters higher than the elevation of the corresponding burner in each part.

3. The additive injection device system according to claim 1 or 2, characterized in that: The arrangement elevation of the alkali metal concentration measurement module arranged in the reduction area is 0.3 to 0.5 m higher than the elevation of the corresponding burner.

4. The additive injection device system according to any one of claims 1 to 3, characterized in that: Two to three alkali metal concentration measuring devices are provided on the four water-cooled walls of each part of the main burner area; Preferably, 2 to 3 alkali metal concentration measuring devices are provided on each of the four water-cooled walls of the reduction zone; Preferably, on the same water-cooled wall, the alkali metal concentration measuring devices are evenly arranged along the furnace width according to the number of arranged devices, and the distance between adjacent alkali metal concentration measuring devices is 0.3 to 0.4 times the furnace width.

5. The additive injection device system according to any one of claims 1 to 4, characterized in that: One to two additive injection ports are provided on the four water-cooled walls of each part of the main burner area; Preferably, 1 to 2 additive injection ports are provided on each of the four water-cooled walls of the reduction zone; Preferably, each additive injection port is connected to an independent additive delivery device; Preferably, on the same water-cooled wall, the distance between the additive injection port and the adjacent alkali metal concentration measuring device is 3 to 5 m; Preferably, on the same water-cooled wall, the angle between the center line of the additive injection port and the water-cooled wall surface is 50° to 60°.

6. A method for using the additive injection device system based on alkali metal concentration field gradient attenuation control according to any one of claims 1 to 5, characterized in that: The method of use includes: When the alkali metal concentration in the flue gas measured by the alkali metal concentration measurement module and the alkali metal theoretical concentration C0 do not meet the constraint conditions, the additive injection module injects additives into the corresponding area inside the furnace; The constraints include: The average measured value C of the alkali metal concentration in the A layer of the main burner area A ≤0.613C0; The average measured value C of the alkali metal concentration in the main burner area B layer B ≤0.486C0; The average measured value C of the alkali metal concentration in the reduction zone C layer C ≤0.2C0.

7. The method of use according to claim 6, characterized in that: The calculation formula of the theoretical alkali metal concentration C0 is: C0=W 煤 ×A×C Na+K ÷Q 理论烟气量 Among them, W 煤 is the coal feeding rate, t / h; A is the mass percentage of ash, wt%; C Na+K is the alkali metal content in coal ash, wt%; Q 理论烟气量 is the theoretical flue gas volume, t / h.

8. The method of use according to claim 6 or 7, characterized in that: The injection amount of the additive is calculated by the following formula: Q A =(0.613C0-C A )×Q A烟气量 ×α Q B =(0.486C0-C A )×Q B烟气量 ×α Q C =(0.2C0-C A )×Q C烟气量 ×α Among them, Q A The additive amount of the main burner area A layer, kg; Q A烟气量 The flue gas volume corresponding to all coal fed into the upstream of the additive nozzle in layer A of the main burner area, t / h; Q B The additive amount of the main burner area B layer, kg; Q B烟气量 The flue gas volume corresponding to all coal fed into the upstream of the additive nozzle in the B layer of the main burner area, t / h; Q C Q is the additive amount of the reduction zone C layer, kg; C烟气量 is the flue gas volume corresponding to all coal fed into the furnace upstream of the additive nozzle in the C layer of the reduction area, t / h; α is the additive correlation coefficient, and the value of kaolin is 11.28~13.

57.

9. The method of use according to any one of claims 6 to 8, characterized in that: The fineness R90 of the additive is 8% to 12%.

10. The method of use according to any one of claims 6 to 9, characterized in that: The powder feeding speed of the additive is 22-28 m / s.

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