Biomass blending combustion boiler low-nitrogen combustion system based on ammonia spraying in high-temperature area and control method of biomass blending combustion boiler low-nitrogen combustion system

Abstract

The invention provides a biomass blending combustion boiler low-nitrogen combustion system based on high-temperature ammonia spraying and a control method of the biomass blending combustion boiler low-nitrogen combustion system. Comprising a feeding assembly used for providing fuel; the ammonia supply assembly is used for providing ammonia; the gas supply assembly is used for providing oxygen; the boiler is sequentially divided into a main combustion area, a reduction area and a burnout area according to the height direction; a combustor is arranged in the main combustion area, the main combustion area obtains fuel provided by the feeding assembly, and fuel-rich combustion is conducted through the combustor. The reduction area obtains ammonia provided by the ammonia supply assembly, and compounds formed after fuel in the main combustion area is combusted and the ammonia are subjected to oxygen-deficient combustion; the burnout area obtains oxygen provided by the gas supply assembly and ammonia provided by the ammonia supply assembly, and compounds formed after combustion in the reduction area, the ammonia and the oxygen are subjected to oxygen-enriched combustion; the detection unit is used for detecting the content of oxynitride in the burnout area; and the control unit is used for controlling the material supply assembly, the ammonia supply assembly and the gas supply assembly according to the content of the oxynitride in the burnout area.

Description

Technical Field

[0001] The present invention belongs to the field of fuel combustion, and in particular relates to a low-nitrogen combustion system of a biomass blending boiler based on high-temperature zone ammonia injection and a control method thereof. Background Art

[0002] At present, my country's energy structure is still dominated by fossil energy, of which coal accounts for more than 55% of total energy consumption. A large amount of CO2 is produced during the combustion of coal, so carbon reduction can be achieved by replacing part of the coal with "zero-carbon" fuels to respond to the country's "carbon peak and carbon neutrality" goals.

[0003] Conventional Selective Non-Catalytic Reduction (SNCR) technology usually injects ammonia reducing agents between 850℃ and 1100℃ to reduce nitrogen oxides to N2 and H2O. The existing SNCR technology still has shortcomings. Ammonia injection requires the flue gas temperature to be between 850℃-1100℃, which is a relatively narrow temperature window. In addition, the emission of nitrogen oxides at its outlet is high, and a certain amount of ammonia slip will still occur. Summary of the invention

[0004] The present invention provides a low-nitrogen combustion system for a biomass co-firing boiler based on high-temperature zone ammonia injection and a control method thereof, which can increase the ammonia injection temperature range, reduce the emission of outlet nitrogen oxides, and avoid ammonia slip.

[0005] On the one hand, a low nitrogen combustion system for a biomass co-firing boiler based on high temperature zone ammonia injection is provided, comprising: A fuel supply assembly, for supplying fuel; An ammonia supply component, used for providing ammonia; A gas supply assembly for providing oxygen or air; The boiler is divided into a main combustion zone, a reduction zone and a burnout zone in sequence according to the height direction; a burner is arranged in the main combustion zone, the main combustion zone obtains fuel provided by the feed assembly, and performs fuel-rich combustion through the burner; the reduction zone obtains ammonia provided by the ammonia supply assembly, and performs oxygen-poor combustion with ammonia on the flue gas and incompletely burned fuel formed after the combustion of the fuel in the main combustion zone; the burnout zone obtains oxygen or air provided by the air supply assembly, obtains ammonia provided by the ammonia supply assembly, and performs oxygen-rich combustion with ammonia, air or oxygen on the flue gas and incompletely burned fuel formed after the combustion in the reduction zone; A detection unit, used to detect the content of nitrogen oxides in the burnout zone; The control unit is used to control the material supply component, the ammonia supply component and the gas supply component according to the content of nitrogen oxides in the burnout zone.

[0006] Optionally, the feeding assembly comprises: The pulverized coal supply assembly and the biomass fuel supply assembly are used to provide pulverized coal and biomass fuel respectively; The biomass fuel supply unit sprays the biomass fuel into the reduction zone to burn with the product formed after combustion in the main combustion zone; The biomass fuel supply assembly determines the amount of biomass fuel delivered to the reduction zone by the biomass fuel supply unit according to 10% to 15% of the total fuel calorific value.

[0007] Optionally, the excess air coefficient of the main combustion zone is 0.85~0.95, and the excess air coefficient of the reduction zone is 0.75~0.85.

[0008] Optionally, the temperature range of ammonia spraying in the reduction zone is 1000°C~1200°C, the temperature range of ammonia spraying in the burnout zone is 850°C~1100°C, and the ammonia spraying in the reduction zone is located below the biomass fuel supply assembly, and the ammonia spraying in the burnout zone is located below the gas supply assembly.

[0009] On the other hand, a control method for a low-nitrogen combustion system of a biomass blended combustion boiler based on high-temperature zone ammonia injection is provided, and the control method for a low-nitrogen combustion system of a biomass blended combustion boiler based on high-temperature zone ammonia injection is applied to the low-nitrogen combustion system of a biomass blended combustion boiler based on high-temperature zone ammonia injection as described in any of the above items, comprising: Periodically measure and obtain historical operating data of the low-nitrogen combustion system of the biomass-fired boiler based on ammonia injection in the high-temperature zone; A relationship is constructed based on historical operating data to describe the relationship between inlet parameters and outlet nitrogen oxide content; Obtaining the content of outlet nitrogen oxides detected by the detection unit; When the outlet nitrogen oxide emissions do not meet the requirements, the control unit generates control instructions based on the relationship to adjust the inlet parameters.

[0010] Optionally, a relational expression is constructed to describe the relationship between the inlet parameter and the amount of outlet nitrogen oxides, including: Construct the first relation based on historical operation data , which is used to describe the relationship between the amount of ammonia sprayed in the reduction zone, the amount of ammonia sprayed in the burnout zone, the amount of biomass added, the burnout air rate, the biomass addition ratio, the boiler load, the total air volume and the outlet nitrogen oxide emissions. , , , , , , and The original data of ammonia injection amount in the reduction zone, ammonia injection amount in the burnout zone, biomass input amount, burnout air rate, biomass input ratio, boiler load, total air volume and outlet nitrogen oxide emission were obtained through normalization; Construct the second relationship based on historical operation data , used to describe the relationship between biomass input amount, biomass input ratio, boiler load, and total air volume; Construct the third relationship based on historical operation data , used to describe the relationship between burnout air rate, boiler load and total air volume.

[0011] Optionally, when the outlet nitrogen oxide emission does not meet the requirement, the control unit generates a control instruction according to the relationship to adjust the inlet parameters, including: When the outlet nitrogen oxide emissions do not meet the requirements, the ammonia injection amount in the reduction zone, the ammonia injection amount in the burnout zone, the biomass input amount, the burnout wind rate, and the biomass input ratio are adjusted according to the first to third equations.

[0012] Optionally, the first relational expression is: , In the formula, and Determined based on historical operating data, , .

[0013] Optionally, the second relational expression is: , In the formula, and Determined based on historical operating data, , .

[0014] Optionally, the third relational expression is: , In the formula, and Determined based on historical operating data, , .

[0015] The technical solution provided by the embodiments of the present disclosure brings the following beneficial effects: In an embodiment of the present disclosure, a low-nitrogen combustion system for a biomass co-firing boiler based on ammonia injection in a high-temperature zone is provided, and the low-nitrogen combustion system includes a main combustion zone, a reduction zone, and a burnout zone, and also includes a feed component, an ammonia supply component, and an ammonia supply component. The emission of outlet nitrogen oxides is detected by a detection unit. When the emission of outlet nitrogen oxides does not meet the requirements, the emission of outlet nitrogen oxides is reduced by adjusting the feed component, the ammonia supply component, and the gas supply component. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 A schematic diagram of the structure of a low-nitrogen combustion system for a biomass-blended boiler based on high-temperature zone ammonia injection provided in an embodiment of the present disclosure; Figure 2 A method flow chart of a control method for a low-nitrogen combustion system of a biomass-blended combustion boiler based on high-temperature zone ammonia injection provided in an embodiment of the present disclosure; Figure 3 A set of historical operating data of a low-nitrogen combustion system of a biomass co-firing boiler based on ammonia injection in the high-temperature zone is provided for an embodiment of the present disclosure.

[0018] The reference numerals are as follows: 1: Feeding assembly; 2: Ammonia supply component; 3: Air supply assembly; 4: boiler; 41: main combustion zone; 411: burner; 42: reduction zone; 43: burnout zone; 5: Detection unit; 6: Control unit. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are 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 creative work are within the scope of protection of the present invention.

[0020] Research has shown that ammonia injection in high-temperature zones can replace the current SNCR technology. Ammonia injection in high-temperature reduction zones is a multi-zone ammonia injection technology based on air classification. Ammonia reducing agents are injected into the high-temperature, oxygen-deficient environment formed in the furnace reduction zone, and at the same time, ammonia reducing agents are injected below the burnout tuyere to reduce NOx in the flue gas. Compared with conventional SNCR technology, this technology has a lower concentration of nitrogen oxides at the outlet and does not produce ammonia escape.

[0021] The main factors affecting the denitrification efficiency of ammonia injection in the high-temperature reduction zone are the temperature and oxygen concentration at the ammonia injection position, which should generally be less than 0.5%. Due to the uneven oxygen concentration in the boiler, there are areas with high oxygen concentration, which leads to ammonia oxidation and reduces the denitrification efficiency of high-temperature ammonia injection. Therefore, this technology injects biomass into the reduction zone to reduce the oxygen concentration in the reduction zone, form a more uniform reducing atmosphere, and improve the NOx reduction efficiency.

[0022] Figure 1 This is a schematic diagram of a low-nitrogen combustion system for a biomass-fired boiler based on high-temperature ammonia injection provided by an embodiment of the present disclosure. Figure 1 The system comprises: A fuel supply assembly 1, used for supplying fuel; an ammonia supply component 2, for providing ammonia; A gas supply component 3, used for providing oxygen or air; The boiler 4 is divided into a main combustion zone 41, a reduction zone 42 and a burnout zone 43 in sequence according to the height direction; a burner 411 is arranged in the main combustion zone 41, and the main combustion zone 41 obtains the fuel provided by the feed assembly 1, and performs fuel-rich combustion through the burner 411; the reduction zone 42 obtains ammonia provided by the ammonia supply assembly 2, and performs oxygen-poor combustion on the flue gas and the incompletely burned fuel formed after the combustion of the fuel in the main combustion zone 41 with ammonia; the burnout zone 43 obtains oxygen or air provided by the air supply assembly 3, obtains ammonia provided by the ammonia supply assembly 2, and performs oxygen-rich combustion on the flue gas and the incompletely burned fuel formed after the combustion in the reduction zone 42 with ammonia, air or oxygen; A detection unit 5, used to detect the content of nitrogen oxides in the burnout zone 43; The control unit 6 is used to control the material supply assembly 1 , the ammonia supply assembly 2 and the gas supply assembly 3 according to the content of nitrogen oxides in the burnout zone 43 .

[0023] In an embodiment of the present disclosure, a low-nitrogen combustion system for a biomass co-firing boiler based on ammonia injection in a high-temperature zone is provided, and the low-nitrogen combustion system includes a main combustion zone, a reduction zone, and a burnout zone, and also includes a feed component, an ammonia supply component, and an ammonia supply component. The emission of outlet nitrogen oxides is detected by a detection unit. When the emission of outlet nitrogen oxides does not meet the requirements, the emission of outlet nitrogen oxides is reduced by adjusting the feed component, the ammonia supply component, and the gas supply component.

[0024] In the embodiment of the present disclosure, the feeding assembly 1 comprises: The pulverized coal supply assembly 11 and the biomass fuel supply assembly 12 are used to provide pulverized coal and biomass fuel respectively; The biomass fuel supply unit 12 arranges the biomass fuel with the front and rear walls facing each other, and sprays the biomass fuel into the reduction zone in the form of a swirl flow to burn with the product formed after the main combustion zone.

[0025] In the embodiment of the present disclosure, the biomass fuel feeding unit arranges the biomass fuel in a counter-attack form and sprays it into the main combustion zone in the form of a swirl, which is beneficial to the full mixing of the biomass fuel and coal powder and can stabilize the combustion flame, thereby facilitating the combustion effect of the fuel.

[0026] In the embodiment of the present disclosure, the biomass fuel supply unit 12 can spray the biomass fuel through the biomass swirl feeder, thereby spraying the biomass fuel into the reduction zone in the form of a swirl.

[0027] In the embodiment of the present disclosure, the amount of biomass fuel delivered to the reduction zone by the biomass fuel supply unit is determined based on 10% to 15% of the total fuel calorific value in the main combustion zone.

[0028] In the embodiment of the present disclosure, the amount of biomass fuel is determined according to the above method, which can ensure that the reduction zone is maintained at a good combustion temperature, so that the fuel has a better combustion effect.

[0029] In the embodiment of the present disclosure, the ammonia supply component 2 is disposed in the reduction zone 42 and the burnout zone 43 , and the ammonia supply component 2 can spray ammonia water into the reduction zone 42 and the burnout zone 43 through an ammonia water nozzle spray gun.

[0030] In the embodiment of the present disclosure, the gas supply component 3 is disposed in the burnout zone 43, and the gas supply component 3 can supply oxygen or gas through the SOFA wind nozzle.

[0031] In the disclosed embodiment, the temperature range of ammonia spraying in the reduction zone is 1000°C ~ 1200°C, the temperature range of ammonia spraying in the burnout zone is 850°C ~ 1100°C, and the ammonia spraying in the reduction zone is located below the biomass fuel supply assembly, and the ammonia spraying in the burnout zone is located below the gas supply assembly.

[0032] In the embodiment of the present disclosure, the above-mentioned temperature is adopted, and the temperatures of the burnout zone and the reduction zone are at the optimal temperatures for the ammonia reduction reaction. Controlling the temperature of the reduction zone can reduce ammonia oxidation.

[0033] In the embodiment of the present disclosure, the excess air coefficient of the main combustion zone is 0.85~0.95, and the excess air coefficient of the reduction zone is 0.75~0.85.

[0034] In the embodiments disclosed herein, it is clarified that the excess air coefficient of the main combustion zone is different from the fuel staging, and that the reduction of nitrogen oxides in the reduction zone requires lowering of the oxygen content to reduce the ammonia oxidation reaction.

[0035] In the embodiment of the present disclosure, the characteristics of the burnout zone need to be considered. Considering that biomass and NH3 are easily burnt out, the burnout air rate can be reduced and the burnout air rate can be controlled below 30%.

[0036] In the embodiment of the present disclosure, the detection component 5 includes NOx Detection probe. In the disclosed embodiment, pulverized coal is sprayed into the furnace through the burners 411 on the left and right sides of the furnace of the main combustion zone for combustion, wherein the burner is a low-nitrogen burner, and the excess air coefficient of the main combustion zone is controlled at 0.85~0.95, so that the main combustion zone forms fuel-rich combustion and the temperature is maintained at about 1300°C.

[0037] Swirl biomass sampling nozzles 412 are arranged on the front and rear sides of the reduction zone furnace. The biomass fuel is fed in a swirling form. The calorific value of the biomass fuel fed into the reduction zone furnace accounts for 10% to 15% of the total calorific value of the boiler fuel, which is beneficial to reducing the generation of nitrogen-containing compounds after combustion in the reduction zone.

[0038] In the embodiment of the present disclosure, the gaseous products generated in the main combustion zone 41 and the incompletely burned solid products (such as solid coke and CO, HCN, NH i All gases (such as NO) enter the reduction zone 42 of the boiler, and the excess air coefficient of the reduction zone 42 is controlled at 0.75-0.85; due to the lack of oxygen in the reduction zone 42, a reducing atmosphere is formed, which can x Reduced to N2.

[0039] In the embodiment of the present disclosure, the reduction zone 42 is also provided with an ammonia supply device to spray ammonia in the reduction zone (also a high-temperature zone) in the form of atomization at room temperature, which can further reduce NO in the flue gas. x Reduced to N2. At the same time, spraying at room temperature can control the temperature of the reduction zone at 900~1200℃, reducing the oxidation of NH3 to NO by O2 at high temperature, and reducing the oxidation of NH3 by controlling the temperature.

[0040] In the embodiment disclosed herein, the reduced flue gas and the incompletely reacted coke in the reduction zone 42 all enter the burnout zone 43. The burnout zone 43 is provided with a separate burnout air on the side wall of the furnace. At this time, the excess air coefficient of the burnout zone 43 is controlled to be around 1.1, and the temperature is maintained at 850-1100°C, so that the reaction of NH3 and NOx is in the optimal reaction temperature range; the flue gas and coke that are not completely burned and reacted react completely in the burnout zone 43.

[0041] In the disclosed embodiment, the burnout zone 43 is also provided with an ammonia supply component to further reduce the unreduced NOx in the reduction zone 42 and the burnout zone 43 into N2; the ammonia injection amount of the burnout zone 43 is controlled according to the ammonia content in the tail to reduce ammonia escape. The boiler can ultimately increase the denitrification efficiency to 75% to 85%, which is higher than that of a pure coal combustion unit and a boiler that uses only SNCR denitrification technology. While ensuring the combustion efficiency of the boiler, this embodiment can also solve the problem of poor SNCR denitrification performance during conventional load reduction operation.

[0042] Figure 2A method flow chart of a control method for a low-nitrogen combustion system of a biomass-fired boiler based on high-temperature zone ammonia injection provided by an embodiment of the present disclosure. Figure 2 , this method is used to control Figure 1 The low nitrogen combustion system of the biomass co-firing boiler based on high temperature zone ammonia injection comprises: S101. Periodically measure and obtain historical operation data of a low nitrogen combustion system of a biomass-blended combustion boiler based on ammonia injection in a high temperature zone.

[0043] Figure 3 A set of historical operating data of a low-nitrogen combustion system of a biomass co-firing boiler based on ammonia injection in the high-temperature zone is provided for an embodiment of the present disclosure.

[0044] S102. Construct a relationship based on historical operation data to describe the relationship between inlet parameters and outlet nitrogen oxide content.

[0045] In one example, step S102 includes: The first step is to construct the first relationship based on historical operation data , which is used to describe the relationship between the amount of ammonia sprayed in the reduction zone, the amount of ammonia sprayed in the burnout zone, the amount of biomass added, the burnout air rate, the biomass addition ratio, the boiler load, the total air volume and the outlet nitrogen oxide emissions. , , , , , , and The original data of ammonia injection amount in the reduction zone, ammonia injection amount in the burnout zone, biomass input amount, burnout air rate, biomass input ratio, boiler load, total air volume and outlet nitrogen oxide emissions were obtained through normalization.

[0046] In the embodiment of the present disclosure, the first relational expression is: , In the formula, and Determined based on historical operating data, , .

[0047] In the embodiment of the present disclosure, by recording the specific values ​​of the ammonia injection amount in the reduction zone, the ammonia injection amount in the burnout zone, the biomass input amount, the burnout air rate, the biomass input ratio, the boiler load, the total air volume and the outlet nitrogen oxide emissions during the operation of the boiler, the first relationship is constructed by recording multiple sets of data and normalizing the data.

[0048] Exemplarily, the first relation is: .

[0049] In the embodiment of the present disclosure, the total air volume includes the burnout air volume and the primary and secondary air volume, and the primary and secondary air refers to the air that delivers the coal powder into the burner.

[0050] In the embodiment of the present disclosure, the burnout air rate is the ratio of the burnout air volume to time, that is, the burnout air volume delivered per hour.

[0051] In the embodiment of the present disclosure, considering the differences between different furnace detection equipment in actual use, and avoiding the influence of dimensions between different parameters and the influence of different orders of magnitude, the maximum-minimum normalization method is adopted, that is, all characteristic parameters are scaled to the interval [0,1], and the normalization method is as follows: , in, represents the characteristic parameter, Represents the original value of the corresponding characteristic parameter, Represents the maximum value of the original data of the secondary characteristic parameter, Represents the minimum value of the original data of the secondary characteristic parameter, and middle The value range is 1~7.

[0052] The second step is to construct the second relationship based on historical operation data , which is used to describe the relationship between biomass input amount, biomass input ratio, boiler load and total air volume.

[0053] In the embodiment of the present disclosure, the second relational expression is: , In the formula, and Determined based on historical operating data, , .

[0054] In the disclosed embodiment, by recording the amount of ammonia sprayed in the reduction zone, the amount of ammonia sprayed in the burnout zone, the amount of biomass fed, the burnout air rate, the biomass fed ratio, the boiler load, the total air volume and the outlet nitrogen oxide emissions during boiler operation, the interaction relationship when the amount of biomass fed, the biomass fed ratio, the boiler load and the total air volume change together is determined, thereby establishing a second relationship. By regulating the amount of biomass fed, the biomass fed ratio, the boiler load and the total air volume through the second relationship, it can be confirmed that the content of outlet nitrogen oxides changes to a large extent.

[0055] Exemplarily, the second relation is: .

[0056] The third step is to construct the third relationship based on historical operation data , used to describe the relationship between burnout air rate, boiler load and total air volume.

[0057] In the embodiment of the present disclosure, the third relational expression is: , In the formula, and Determined based on historical operating data, , .

[0058] Exemplarily, the third relation is .

[0059] In the embodiment of the present disclosure, by recording the values ​​of the burnout air rate, boiler load, total air volume and outlet nitrogen oxides during boiler operation, the interaction relationship when the burnout air rate, boiler load and total air volume change together is determined, thereby establishing a third relationship. When the burnout air rate, boiler load and total air volume are regulated by the third relationship, it can be confirmed that the content of outlet nitrogen oxides changes to a greater extent.

[0060] In the disclosed embodiment, the amount of ammonia sprayed in the reduction zone, the amount of ammonia sprayed in the burnout zone, the amount of biomass added, the burnout wind rate, the biomass added ratio, the boiler load, and the total air volume can affect the outlet nitrogen oxide emissions. The amount of ammonia sprayed in the reduction zone, the amount of ammonia sprayed in the burnout zone, the amount of biomass added, the burnout wind rate, the biomass added ratio, the boiler load, and the total air volume alone will change the outlet nitrogen oxide emissions to a certain extent. The amount of ammonia sprayed in the reduction zone, the amount of ammonia sprayed in the burnout zone, the amount of biomass added, the burnout wind rate, the biomass added ratio, the boiler load, and the total air volume construct a first relationship. When the amount of biomass added, the biomass added ratio, the boiler load, and the total air volume change separately, the outlet nitrogen oxide emissions can be affected. When the amount of biomass added, the biomass added ratio, the boiler load, and the total air volume change together, the degree of change in the outlet nitrogen oxide emissions will be greater. The second relationship is constructed to describe the functional relationship between the amount of biomass added, the biomass added ratio, the boiler load, and the total air volume when they change together. Similarly, when the burnout air rate, boiler load, and total air volume change together, the degree of change in the outlet nitrogen oxide emissions will be greater. The third relationship is constructed to describe the relationship between the burnout air rate, boiler load, and total air volume when they change together. The relationship is used to sort out the association of boiler combustion parameters, thereby realizing automatic control of the boiler and ensuring that the outlet nitrogen oxide emissions of the boiler are low.

[0061] S103, obtaining the content of outlet nitrogen oxides detected by the detection unit.

[0062] S104: When the outlet nitrogen oxide emission does not meet the requirement, the control unit generates a control instruction according to the relationship to adjust the inlet parameters.

[0063] In one example, step S103 includes: When the emission of nitrogen oxides at the outlet does not meet the requirements, the ammonia injection amount in the reduction zone, the ammonia injection amount in the burnout zone, the biomass input amount, the burnout wind rate, and the biomass input ratio are adjusted according to the first to third equations.

[0064] In the embodiment of the present disclosure, precise control of outlet nitrogen oxides can be achieved through the first to third relationship equations. When the emission of nitrogen oxides at the boiler outlet does not meet the requirements, the emission of nitrogen oxides at the boiler outlet can be quickly reduced by adjusting the combustion parameters of the boiler.

[0065] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A low nitrogen combustion system for a biomass-fired boiler based on high-temperature ammonia injection, characterized in that: include: A fuel supply assembly, for supplying fuel; An ammonia supply component, used for providing ammonia; A gas supply assembly for providing oxygen or air; The boiler is divided into a main combustion zone, a reduction zone and a burnout zone in sequence according to the height direction; a burner is arranged in the main combustion zone, the main combustion zone obtains fuel provided by the feed assembly, and performs fuel-rich combustion through the burner; the reduction zone obtains ammonia provided by the ammonia supply assembly, and performs oxygen-poor combustion with ammonia on the flue gas and incompletely burned fuel formed after the combustion of the fuel in the main combustion zone; the burnout zone obtains oxygen or air provided by the air supply assembly, obtains ammonia provided by the ammonia supply assembly, and performs oxygen-rich combustion with ammonia, air or oxygen on the flue gas and incompletely burned fuel formed after the combustion in the reduction zone; A detection unit, used to detect the content of nitrogen oxides in the burnout zone; The control unit is used to control the material supply component, the ammonia supply component and the gas supply component according to the content of nitrogen oxides in the burnout zone.

2. The low nitrogen combustion system of a biomass-fired boiler based on high-temperature ammonia injection according to claim 1 is characterized in that: The feeding assembly comprises: The pulverized coal supply assembly and the biomass fuel supply assembly are used to provide pulverized coal and biomass fuel respectively; The biomass fuel supply unit sprays the biomass fuel into the reduction zone to burn with the product formed after combustion in the main combustion zone; The biomass fuel supply assembly determines the amount of biomass fuel delivered to the reduction zone by the biomass fuel supply unit according to 10% to 15% of the total fuel calorific value.

3. The low nitrogen combustion system of a biomass-fired boiler based on high-temperature ammonia injection according to claim 1 is characterized in that: The excess air coefficient of the main combustion zone is 0.85-0.95, and the excess air coefficient of the reduction zone is 0.75-0.

85.

4. The low nitrogen combustion system of a biomass-fired boiler based on high-temperature ammonia injection according to claim 2 is characterized in that: The temperature range of ammonia spraying in the reduction zone is 1000℃~1200℃, and the temperature range of ammonia spraying in the burnout zone is 850℃~1100℃. The ammonia spraying in the reduction zone is located below the biomass fuel supply assembly, and the ammonia spraying in the burnout zone is located below the gas supply assembly.

5. A control method for a low-nitrogen combustion system of a biomass-fired boiler based on high-temperature ammonia injection, characterized in that: The control method of the low-nitrogen combustion system of the biomass blending boiler based on high-temperature ammonia injection is applied to the low-nitrogen combustion system of the biomass blending boiler based on high-temperature ammonia injection as claimed in any one of claims 1 to 4, comprising: Periodically measure and obtain historical operating data of the low-nitrogen combustion system of the biomass-fired boiler based on ammonia injection in the high-temperature zone; A relationship is constructed based on historical operating data to describe the relationship between inlet parameters and outlet nitrogen oxide content; Obtaining the content of outlet nitrogen oxides detected by the detection unit; When the outlet nitrogen oxide emissions do not meet the requirements, the control unit generates control instructions based on the relationship to adjust the inlet parameters.

6. The control method of the low nitrogen combustion system of the biomass co-firing boiler based on high temperature ammonia injection according to claim 5 is characterized in that: The relationship between the inlet parameters and the amount of outlet nitrogen oxides is constructed, including: Construct the first relation based on historical operation data , which is used to describe the relationship between the amount of ammonia sprayed in the reduction zone, the amount of ammonia sprayed in the burnout zone, the amount of biomass added, the burnout air rate, the biomass addition ratio, the boiler load, the total air volume and the outlet nitrogen oxide emissions. , , , , , , and The original data of ammonia injection amount in the reduction zone, ammonia injection amount in the burnout zone, biomass input amount, burnout air rate, biomass input ratio, boiler load, total air volume and outlet nitrogen oxide emission were obtained through normalization; Construct the second relationship based on historical operation data , used to describe the relationship between biomass input amount, biomass input ratio, boiler load, and total air volume; Construct the third relationship based on historical operation data , used to describe the relationship between burnout air rate, boiler load and total air volume.

7. The low nitrogen combustion system of a biomass-fired boiler based on high-temperature ammonia injection according to claim 6 is characterized in that: When the outlet nitrogen oxide emissions do not meet the requirements, the control unit generates control instructions according to the relationship to adjust the inlet parameters, including: When the outlet nitrogen oxide emissions do not meet the requirements, the ammonia injection amount in the reduction zone, the ammonia injection amount in the burnout zone, the biomass input amount, the burnout wind rate, and the biomass input ratio are adjusted according to the first to third equations.

8. The low nitrogen combustion system for biomass-fired boiler based on high temperature ammonia injection according to claim 6 or 7, characterized in that: The first relation is: ， In the formula, and Determined based on historical operating data, , .

9. The low nitrogen combustion system for biomass co-firing boiler based on high temperature ammonia injection according to claim 6 or 7, characterized in that: The second relation is: ， In the formula, and Determined based on historical operating data, , .

10. The control method of the low nitrogen combustion system of the biomass co-firing boiler based on high temperature ammonia injection according to claim 6 or 7, characterized in that: The third relational expression is: ， In the formula, and Determined based on historical operating data, , .

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