Anti-coking corrosion biomass blending combustion method and system

Abstract

The present application provides a biomass blending combustion method and system for preventing coking and corrosion, belonging to the technical field of biomass or solid waste blending combustion of pulverized coal boilers, which can significantly alleviate or solve the problems of poor fuel matching, easy coking and corrosion of the nozzle, high risk of alkali metal deposition and sulfur and chlorine corrosion in the existing blending combustion process, obtain operating parameters such as load demand, raw material characteristics, combustion state, nozzle thermal state, pollutant emission state and coking and corrosion trend, and generate a blending combustion control target; the pulverized coal, biomass or solid waste raw materials and solid waste pyrolysis gas are delivered by shunting, particle size matching and sulfur and chlorine fixation treatment, and a dense phase mixed combustion gas stream and a supplementary combustion gas stream are formed through staged combustion air; a local reducing atmosphere is formed in the combustion mixing area, a cooling gas film is formed in the nozzle area and the alkali metal components are captured, and then the blending combustion control target is feedback corrected. The present application can improve the blending combustion stability and reduce the risk of nozzle coking and corrosion.

Description

Technical Field

[0001] This invention belongs to the field of biomass or solid waste co-firing technology in pulverized coal boilers, specifically relating to a biomass co-firing method and system for preventing coking and corrosion. Background Technology

[0002] With the increasing demand for flexible peak shaving, low-carbon operation, and solid waste resource utilization in coal-fired power units, the co-firing of biomass and solid waste raw materials containing organic components in existing pulverized coal boilers has become an important technological direction for reducing fossil fuel consumption and improving the energy utilization level of solid waste. Biomass raw materials are typically characterized by high volatile matter, low ignition temperature, and strong reactivity, while solid waste pyrolysis products may simultaneously include pyrolysis gas, pyrolysis semi-coke, and tar-containing gaseous components, among other multiphase media. These fuels and pulverized coal differ significantly in particle size distribution, volatile matter release rate, ignition and burnout process, ash composition, and pollutant release pathways. Direct co-firing with traditional pulverized coal burners can easily lead to unstable combustion organization and mismatches between local temperature and atmosphere fields.

[0003] In pulverized coal boilers that co-fire biomass or solid waste, the burner not only needs to stably transport and mix pulverized coal and co-fired fuel, but also needs to adapt to the high content of alkali metals, sulfur, and chlorine in the biomass or solid waste raw materials. Alkali metals such as potassium and sodium in biomass or solid waste easily react with silicon, aluminum, sulfur, and chlorine in coal ash under high-temperature conditions, forming low-melting-point salts or eutectics, which deposit at the burner nozzle, near-wall area of ​​the furnace, and on the heating surfaces, leading to coking, ash accumulation, and blockage. Simultaneously, the release of chlorine and sulfur-containing components during combustion exacerbates high-temperature corrosion of the nozzle metal walls and furnace heating surfaces, increasing the subsequent flue gas purification load. Therefore, biomass or solid waste co-fired burners cannot only focus on fuel delivery and combustion; they also need to consider preventing coking and corrosion in the nozzle area and controlling pollutant sources.

[0004] In existing pulverized coal boiler co-firing technologies, some schemes employ the addition of separate biomass nozzles, auxiliary spray guns, or external feeding channels to introduce biomass pellets, pyrolysis coke, or pyrolysis gas into the furnace for co-combustion with pulverized coal. While these schemes can achieve a certain proportion of co-firing, most are still based on conventional pulverized coal burner structures and lack separate channel conveying and staged mixing designs to address the differences in combustion characteristics among pulverized coal, biomass solid feedstock, solid waste pyrolysis gas, and combustion air. This easily leads to problems such as uneven solid particle delivery, localized enrichment of pyrolysis gas, flame root fluctuations, and an increase in unburned particles. Although some burners are equipped with staged air or cooling structures, the lack of coordinated control between the cooling airflow, combustion airflow, reducing airflow, and fuel flow makes it difficult to simultaneously meet the requirements of stable combustion, complete combustion, coking prevention, and pollutant source suppression.

[0005] Furthermore, existing co-firing burners lack targeted in-situ control methods for alkali metal, sulfur-containing, and chlorine-containing components released from biomass or solid waste combustion. Conventional solutions typically rely on subsequent dust removal, desulfurization, denitrification, or flue gas purification systems to treat pollutants, failing to provide coordinated control over alkali metal deposition, chlorine-sulfur corrosion, and fuel nitrogen conversion in the burner nozzle area or during the initial combustion stage. When the co-firing ratio increases or the unit load changes, nozzle wall temperature, furnace temperature, and flow and pressure in each channel are prone to fluctuations, further increasing the risk of coking corrosion. Without a feedback adjustment mechanism based on nozzle wall temperature, furnace temperature, combustion stability, channel flow, channel pressure, and coking corrosion trends, it is difficult to adjust the co-firing ratio, combustion air ratio, cooling gas flow, reducing gas flow, and pyrolysis gas injection status in a timely manner.

[0006] Therefore, there is an urgent need for a method and system suitable for the co-firing of biomass or solid waste in pulverized coal boilers. This system should enable pulverized coal, biomass or solid waste raw materials, solid waste pyrolysis gas, primary combustion air, and secondary combustion air to be transported separately and mixed and combusted in stages. Simultaneously, it should form a cooling gas film protection, in-situ capture of alkali metals, control of reducing atmosphere, and synergistic effects of sulfur and chlorine fixation in the burner nozzle area. Furthermore, it should be able to adaptively adjust based on unit load, nozzle wall temperature, furnace temperature, channel flow rate, channel pressure, and coking corrosion trend to reduce the risk of coking corrosion in the nozzle and near-wall areas, and improve the stability of the co-firing combustion process and the ability to control pollutant sources. Summary of the Invention

[0007] The present invention aims to solve at least one of the technical problems existing in the prior art, and to provide a biomass co-firing method and system for preventing coking and corrosion.

[0008] This invention provides a method for preventing coking and corrosion through biomass co-firing, comprising the following steps: S1: Obtain operating parameters that characterize the load demand, fuel supply status, biomass or solid waste feedstock characteristics, combustion status, nozzle thermal status, pollutant emission status, and coking corrosion trend of coal-fired units. S2: Generate co-firing control targets based on the operating parameters. The co-firing control targets include the co-firing ratio of biomass or solid waste, the coal powder supply, the solid waste pyrolysis gas injection, the combustion air distribution, the anti-coking and corrosion control, and the pollutant element control. S3: According to the co-firing control target, pulverized coal, biomass or solid waste raw materials and solid waste pyrolysis gas are separately transported, and the biomass or solid waste raw materials meet the particle size matching requirements with the pulverized coal before entering the combustion mixing zone, and the solid waste pyrolysis gas completes the adsorption and fixation treatment of sulfur-containing components and chlorine-containing components before entering the combustion mixing zone. S4: According to the combustion air distribution, the coal powder, biomass or solid waste raw materials and solid waste pyrolysis gas after adsorption and fixation treatment are mixed with the staged combustion air, so that the primary combustion air forms a dense phase mixed combustion airflow with the coal powder, biomass or solid waste raw materials and solid waste pyrolysis gas, and the secondary combustion air supplies supplementary combustion airflow to the periphery of the dense phase mixed combustion airflow between the combustion mixing area and the burner nozzle inlet side, or at the burner nozzle inlet side, to form a staged combustion process; S5: Based on the dense-phase mixed combustion gas flow, the supplementary combustion gas flow, and the amount of pollutant element regulation, a local reducing atmosphere is formed in the combustion mixing region to regulate the fuel nitrogen conversion pathway; S6: Based on the nozzle thermal state formed by the staged combustion process and the anti-coking corrosion control amount, a cooling gas film is formed in the burner nozzle area, and the alkali metal components released by combustion are captured by the alkali metal adsorption layer. Combined with the adsorption and fixation treatment results of the sulfur-containing components and chlorine-containing components, the nozzle pollution corrosion control state is obtained. S7: Based on the nozzle pollution corrosion control state and the corresponding nozzle thermal state, combustion state, pollutant emission state and coking corrosion trend, the coking control target is corrected by feedback.

[0009] Furthermore, the characteristics of the biomass or solid waste raw materials include at least one of volatile matter, ash content, moisture content, particle size, alkali metal content, sulfur content, and chlorine content; the co-firing control target is determined based on the characteristics of the biomass or solid waste raw materials, the load demand of the coal-fired unit, and the coking corrosion trend.

[0010] Specifically, ensuring that the biomass or solid waste raw material and the pulverized coal meet the particle size matching requirements includes: crushing, screening, or classifying and conveying the biomass particles, solid waste particles, or solid waste pyrolysis semi-coke according to the particle size distribution of the pulverized coal and the ignition characteristics of the biomass or solid waste raw material.

[0011] Specifically, the staged combustion process includes: sending the primary combustion air into the combustion mixing zone to form the dense phase combustion airflow; and sending the secondary combustion air between the combustion mixing zone and the burner nozzle inlet side, or into the burner nozzle inlet side, to form the supplementary combustion airflow.

[0012] Preferably, forming the nozzle contamination corrosion control state includes: forming the cooling gas film flowing along the metal wall of the burner nozzle in the burner nozzle area, and contacting and fixing the potassium-containing component, sodium-containing component, or alkali-containing aerosol with the alkali metal adsorption layer.

[0013] Specifically, forming the local reducing atmosphere includes: introducing a reducing gas containing CO or H2 into the combustion mixing zone, or introducing the reducing components in the solid waste pyrolysis gas into the combustion mixing zone; the sulfur-containing components and the chlorine-containing components are fixed by contacting the calcium-based adsorbent material.

[0014] Furthermore, the feedback correction of the co-firing control target includes: When the thermal state of the nozzle exceeds the preset nozzle thermal threshold, or the coking corrosion trend exceeds the preset coking corrosion trend threshold, the proportion of biomass or solid waste co-firing is reduced, or the amount of anti-coking corrosion control is increased. When the combustion state does not meet the requirements for stable combustion, adjust the injection rate of the solid waste pyrolysis gas or the distribution rate of the combustion-supporting air; and When the pollutant emission status exceeds the preset emission threshold, the amount of pollutant element regulation or the amount of combustion air distribution is adjusted.

[0015] Another aspect of the present invention provides a biomass co-firing system for preventing coking corrosion, comprising: The main injection unit includes a pulverized coal conveying channel, a biomass or solid waste raw material conveying channel, a pyrolysis gas injection channel, a primary combustion air channel, and a secondary combustion air channel arranged coaxially from the inside to the outside. These channels are used to convey pulverized coal, biomass or solid waste raw materials, solid waste pyrolysis gas, and staged combustion air, respectively. The outlet ends of the pulverized coal conveying channel, the biomass or solid waste raw material conveying channel, and the pyrolysis gas injection channel are all connected to the combustion mixing zone. The combustion mixing zone is located within the main injection unit and is close to the burner nozzle inlet side. The raw material pretreatment unit is connected to the feed side of the biomass or solid waste raw material conveying channel, and is used to ensure that the biomass or solid waste raw material and coal powder meet the particle size matching requirements. A pyrolysis gas supply unit, connected to the pyrolysis gas injection channel, is used to supply solid waste pyrolysis gas to the combustion mixing zone; The combustion air graded supply unit is connected to the primary combustion air channel and the secondary combustion air channel respectively, and is used to supply primary combustion air to the combustion mixing zone and supply secondary combustion air to the position near the burner nozzle; The anti-coking corrosion unit is located in the burner nozzle area and is used to form a cooling gas film in the burner nozzle area to isolate and capture alkali metal components. A pollution element control unit, connected to the combustion mixing zone and the flow path before the solid waste pyrolysis gas enters the combustion mixing zone, is used to create a local reducing atmosphere and fix sulfur-containing or chlorine-containing components; and The intelligent adjustment unit is connected to the main injection unit, the pyrolysis gas supply unit, the combustion air graded supply unit, the anti-coking and corrosion unit, and the pollutant element regulation unit, respectively, and is used to generate and correct the co-firing control target according to the co-firing control parameters.

[0016] Furthermore, the raw material pretreatment unit includes at least one of a crushing section, a screening section, and a feeding section, wherein the feeding section is connected to the biomass or solid waste raw material conveying channel; the pyrolysis gas supply unit includes a dispersing injection hole, a micro-orifice nozzle, or an annular injection structure; the outlet of the primary combustion air channel is connected to the combustion mixing zone, and the outlet of the secondary combustion air channel is located between the combustion mixing zone and the burner nozzle inlet side, or located on the burner nozzle inlet side, to supply supplementary combustion gas flow to the periphery of the dense phase mixed combustion gas flow formed by the combustion mixing zone.

[0017] Specifically, the anti-coking corrosion unit includes a cooling gas protection structure and an alkali metal adsorption structure. The cooling gas protection structure is located outside the burner nozzle, and the alkali metal adsorption structure is located on the inner wall of the burner nozzle or in the furnace near the nozzle area. The pollutant element control unit includes a reducing gas supply structure and a calcium-based sulfur and chlorine fixation structure. The reducing gas supply structure is connected to the combustion mixing zone, and the calcium-based sulfur and chlorine fixation structure is located in the flow path before the solid waste pyrolysis gas enters the combustion mixing zone. The intelligent adjustment unit is used to acquire co-firing control parameters and generate or correct the co-firing control target based on the co-firing control parameters. The co-firing control parameters include at least one of load matching parameters, fuel adaptation parameters, and nozzle protection feedback parameters.

[0018] The beneficial effects of this invention are as follows: This invention utilizes multi-channel diversion and staged combustion air supply to create a dense-phase mixed combustion gas flow in the combustion mixing zone, consisting of pulverized coal, biomass or solid waste raw materials, and solid waste pyrolysis gas. A supplementary combustion gas flow is also formed at the burner nozzle inlet side, improving the mixing compatibility and combustion stability of different fuel media. Particle size matching reduces the transport and ignition differences between biomass or solid waste raw materials and pulverized coal. Sulfur and chlorine removal treatment before the solid waste pyrolysis gas enters the combustion mixing zone, a localized reducing atmosphere in the combustion mixing zone, a cooling gas film in the burner nozzle area, and an alkali metal adsorption layer reduce the coking corrosion effects of sulfur-containing components, chlorine-containing components, alkali metal components, and high-temperature flue gas on the burner nozzle. By adjusting the co-firing control target based on nozzle thermal state, combustion state, pollutant emission state, and coking corrosion trend feedback, the invention achieves coordinated regulation of the co-firing ratio, pyrolysis gas injection rate, combustion air distribution rate, anti-coking corrosion control rate, and pollutant element control rate, thereby improving the operational adaptability of the pulverized coal boiler's biomass or solid waste co-firing process. Attached Figure Description

[0019] Figure 1 A flowchart illustrating the steps of a biomass co-firing method for preventing coking corrosion according to a specific embodiment of the present invention; Figure 2 This is a connection block diagram of a biomass co-firing system for preventing coking corrosion according to a specific embodiment of the present invention. Detailed Implementation

[0020] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0021] like Figure 1 As shown in the figure, a biomass co-firing method for preventing coking and corrosion provided by a specific embodiment of the present invention includes the following steps: S1: Obtain operating parameters that characterize the load demand, fuel supply status, biomass or solid waste feedstock characteristics, combustion status, nozzle thermal status, pollutant emission status, and coking corrosion trend of coal-fired units. S2: Generate co-firing control targets based on the operating parameters. These targets include the biomass or solid waste co-firing ratio, pulverized coal supply, solid waste pyrolysis gas injection rate, combustion air distribution rate, anti-coking and corrosion regulation rate, and pollutant element regulation rate. The anti-coking and corrosion regulation rate characterizes the control amount for adjusting thermal scouring, alkali metal deposition, and sulfur- and chlorine-containing corrosion in the burner nozzle area. This rate includes at least one of the following: cooling gas flow rate, cooling gas film coverage intensity, alkali metal adsorption layer working state, and calcium-based adsorption material working state. The pollutant element regulation rate characterizes the control amount for adjusting the release or conversion process of fuel nitrogen, sulfur-containing components, and chlorine-containing components. This rate includes at least one of the following: reducing gas flow rate, reducing gas inlet location, solid waste pyrolysis gas pretreatment intensity, and staged combustion air ratio. S3: According to the co-firing control target, pulverized coal, biomass or solid waste raw materials and solid waste pyrolysis gas are separately transported, and the biomass or solid waste raw materials meet the particle size matching requirements with the pulverized coal before entering the combustion mixing zone, and the solid waste pyrolysis gas completes the adsorption and fixation treatment of sulfur-containing components and chlorine-containing components before entering the combustion mixing zone. S4: According to the combustion air distribution, the coal powder, biomass or solid waste raw materials and solid waste pyrolysis gas after adsorption and fixation treatment are mixed with the staged combustion air, so that the primary combustion air forms a dense phase mixed combustion airflow with the coal powder, biomass or solid waste raw materials and solid waste pyrolysis gas, and the secondary combustion air supplies supplementary combustion airflow to the periphery of the dense phase mixed combustion airflow between the combustion mixing area and the burner nozzle inlet side, or at the burner nozzle inlet side, to form a staged combustion process; S5: Based on the dense-phase mixed combustion gas flow, the supplementary combustion gas flow, and the amount of pollutant element regulation, a local reducing atmosphere is formed in the combustion mixing region to regulate the fuel nitrogen conversion pathway; S6: Based on the nozzle thermal state formed by the staged combustion process and the anti-coking corrosion control amount, a cooling gas film is formed in the burner nozzle area, and the alkali metal components released during combustion are captured by the alkali metal adsorption layer. Combined with the adsorption and fixation results of the sulfur-containing and chlorine-containing components, the nozzle pollution corrosion control state is obtained. The nozzle pollution corrosion control state is used to characterize the comprehensive state of the burner nozzle area after cooling gas film protection, alkali metal component capture, and sulfur- and chlorine-containing component adsorption and fixation treatment. The nozzle pollution corrosion control state includes at least one of the following: cooling gas film coverage state, nozzle wall temperature change state, alkali metal component capture state, calcium-based adsorption material working state, and sulfur- and chlorine-containing component adsorption and fixation state. S7: Based on the nozzle pollution corrosion control state and the corresponding nozzle thermal state, combustion state, pollutant emission state and coking corrosion trend, the coking control target is corrected by feedback.

[0022] In one embodiment, the load demand of the coal-fired unit includes at least one of the following: current load, target load, load change rate, and low-load stable combustion demand; the fuel supply status includes the pulverized coal supply status, biomass or solid waste feedstock supply status, solid waste pyrolysis gas supply status, and the flow or pressure status of each supply channel. By using both the load demand of the coal-fired unit and the fuel supply status as inputs, it is possible to avoid flame fluctuations, incomplete combustion, or abnormal nozzle heat load caused by operating only according to a fixed blending ratio.

[0023] Specifically, the combustion state includes at least one of furnace temperature, flame stability, burner outlet temperature distribution, unburned component changes, and burner channel pressure differential; the nozzle thermal state includes at least one of burner nozzle wall temperature, nozzle wall temperature change rate, and nozzle area temperature deviation; the pollutant emission state includes at least one of nitrogen oxides, sulfur dioxide, hydrogen chloride, carbon monoxide, or flue gas oxygen content. These operating parameters allow for a comprehensive assessment of the co-firing process from the load side, fuel side, combustion side, nozzle side, and emission side.

[0024] Furthermore, the coking corrosion trend is determined based on at least one of the following: nozzle wall temperature change rate, nozzle area temperature deviation, burner channel pressure fluctuation, changes in alkaline components, chlorine components, and sulfur components in the flue gas, flame image changes, and nozzle area deposit detection results. The coking corrosion trend is used to characterize the degree of risk of alkaline deposition, high-temperature corrosion, or ash adhesion in the burner nozzle area.

[0025] Based on the above basic implementation method, the characteristics of the biomass or solid waste raw materials include at least one of volatile matter, ash content, moisture content, particle size, alkali metal content, sulfur content, and chlorine content; the co-firing control target is determined according to the characteristics of the biomass or solid waste raw materials, the load demand of the coal-fired unit, and the coking corrosion trend.

[0026] Further, the biomass or solid waste raw materials include at least one of agricultural and forestry biomass, sludge, municipal solid waste-derived fuel, waste rubber, industrial solid waste containing organic components, and solid waste pyrolysis semi-coke obtained by pyrolysis of the above raw materials. The solid waste pyrolysis gas is a gaseous product containing CO, H2, CH4, light hydrocarbons, H2S, or HCl produced by solid waste under anaerobic or limited-oxygen pyrolysis conditions. The solid waste pyrolysis semi-coke is a solid product that retains fixed carbon, ash, and some inorganic components after solid waste pyrolysis.

[0027] Furthermore, the co-firing control target is not to determine the co-firing ratio of biomass or solid waste alone, but rather to determine the coal powder supply, solid waste pyrolysis gas injection rate, combustion air distribution rate, anti-coking corrosion regulation rate, and pollutant element regulation rate in conjunction with the load demand, raw material calorific value, volatile matter content, moisture content, alkali metal content, sulfur content, chlorine content, and nozzle coking corrosion trend. This improves the adaptability of co-firing while limiting the risks of thermal erosion, alkali deposition, and sulfur and chlorine corrosion in the nozzle area.

[0028] In one specific embodiment, ensuring that the biomass or solid waste raw material and the pulverized coal meet the particle size matching requirements includes: crushing, screening, or classifying and conveying the biomass particles, solid waste particles, or solid waste pyrolysis semi-coke according to the particle size distribution of the pulverized coal and the ignition characteristics of the biomass or solid waste raw material.

[0029] In this embodiment, the particle size matching requirement is used to reduce the differences in settling velocity, ignition delay, and transport stability between biomass or solid waste raw materials and pulverized coal. After particle size matching treatment, the biomass or solid waste raw materials can remain in a suspended mixed state with the pulverized coal in the combustion mixing zone, reducing local enrichment, blockage, or uneven burning.

[0030] Furthermore, when the biomass or solid waste raw material has a high moisture content or a large particle size distribution, the biomass or solid waste raw material is first dried, crushed, or screened before being fed into the biomass or solid waste raw material conveying channel; when the biomass or solid waste raw material is solid waste pyrolysis semi-coke, the crushing strength and feeding speed are determined according to the brittleness, ash content, and fixed carbon content of the solid waste pyrolysis semi-coke, so as to meet the requirements of co-transporting and mixed combustion with pulverized coal.

[0031] In another specific embodiment, the staged combustion process includes: sending the primary combustion air into the combustion mixing region to form the dense phase combustion airflow; and sending the secondary combustion air between the combustion mixing region and the burner nozzle inlet side, or sending it into the burner nozzle inlet side, to form the supplementary combustion airflow.

[0032] In this embodiment, the primary combustion air is used to participate in the initial mixing and ignition of pulverized coal, biomass or solid waste raw materials, and solid waste pyrolysis gas. The secondary combustion air is used to supplement oxygen to the periphery of the dense-phase mixed combustion gas flow, allowing unburned particles and combustible gases to continue burning. Through the staged supply of primary and secondary combustion air, a relatively rich fuel atmosphere can be formed in the combustion mixing zone, and supplementary combustion conditions can be created near the burner nozzle inlet side or nozzle area.

[0033] Specifically, the dense-phase mixed combustion gas flow refers to a gas-solid two-phase or gas-solid multiphase gas flow with a relatively high fuel concentration formed by mixing pulverized coal, biomass or solid waste raw materials, solid waste pyrolysis gas, and primary combustion air; the supplementary combustion gas flow refers to the supplementary oxidation gas flow formed by secondary combustion air around the dense-phase mixed combustion gas flow or at the nozzle inlet side. The dense-phase mixed combustion gas flow and the supplementary combustion gas flow together form a staged combustion process to balance flame stability and burnout performance.

[0034] In another specific embodiment, forming the nozzle contamination corrosion control state includes: forming the cooling gas film flowing along the metal wall of the burner nozzle in the burner nozzle region, and contacting and fixing potassium-containing, sodium-containing, or alkali-containing aerosols with the alkali metal adsorption layer.

[0035] Furthermore, the cooling gas film is formed by a cooling gas protection structure, which may include an annular gas outlet slit, circumferentially distributed gas outlet holes, or an annular gas chamber. After being discharged from the annular gas outlet slit, circumferentially distributed gas outlet holes, or annular gas chamber, the cooling gas flows along the metal wall of the burner nozzle, forming a gas film isolation layer between the high-temperature flue gas and the metal wall of the nozzle. The cooling gas may be nitrogen, carbon dioxide, low-temperature flue gas, or other protective gases that do not affect combustion stability.

[0036] Specifically, the alkali metal adsorption layer is disposed on the inner wall of the burner nozzle, at the outlet of the combustion mixing zone, on the inlet side of the nozzle, or in the furnace near the nozzle area. The alkali metal adsorption layer can be made of kaolin-based materials, aluminosilicate materials, porous materials containing silicon and aluminum, or high-temperature resistant inorganic adsorbent materials. Potassium-containing components, sodium-containing components, or alkali-containing aerosols released during combustion are adsorbed or fixed upon contact with the alkali metal adsorption layer, thereby reducing the formation of low-melting-point alkali-containing deposits in the burner nozzle area.

[0037] In another specific embodiment, forming the local reducing atmosphere includes: introducing a reducing gas containing CO or H2 into the combustion mixing zone, or introducing the reducing components in the solid waste pyrolysis gas into the combustion mixing zone; the sulfur-containing components and the chlorine-containing components are fixed by contacting the calcium-based adsorbent material.

[0038] Furthermore, the localized reducing atmosphere is formed in the mixing zone of pulverized coal, biomass or solid waste raw materials, and solid waste pyrolysis gas. This localized reducing atmosphere is used to regulate the conversion pathway of fuel nitrogen, preferentially converting fuel nitrogen towards nitrogen gas and reducing the source generation of nitrogen oxides. The reducing gas can originate from an external reducing gas supply structure or from CO-rich or H2-rich components in the solid waste pyrolysis gas.

[0039] Specifically, the calcium-based adsorbent material can include calcium oxide, calcium hydroxide, calcium carbonate calcination products, or supported calcium-based porous materials. The solid waste pyrolysis gas contacts the calcium-based adsorbent material before entering the combustion mixing zone, causing H2S, HCl, or other sulfur- and chlorine-containing components to be adsorbed or fixed by reaction. This reduces the proportion of sulfur- and chlorine-containing gaseous components directly entering the combustion mixing zone, thereby reducing the corrosion risk in the nozzle area and the near-wall area of ​​the furnace.

[0040] In another specific embodiment, feedback correction of the co-firing control target includes: When the thermal state of the nozzle exceeds the preset nozzle thermal threshold, or the coking corrosion trend exceeds the preset coking corrosion trend threshold, the proportion of biomass or solid waste co-firing is reduced, or the amount of anti-coking corrosion control is increased. When the combustion state does not meet the requirements for stable combustion, adjust the injection rate of the solid waste pyrolysis gas or the distribution rate of the combustion-supporting air; and When the pollutant emission status exceeds the preset emission threshold, the amount of pollutant element regulation or the amount of combustion air distribution is adjusted.

[0041] Furthermore, the anti-coking corrosion control parameters include at least one of the following: cooling gas flow rate, cooling gas film coverage intensity, alkali metal adsorption layer operating state, and calcium-based adsorption material operating state. The pollutant element control parameters include at least one of the following: reducing gas flow rate, reducing gas inlet location, solid waste pyrolysis gas pretreatment intensity, and staged combustion air ratio.

[0042] Specifically, when the nozzle wall temperature rises, the nozzle wall temperature change rate increases, or the coking corrosion trend intensifies, the cooling gas flow rate is increased or the proportion of biomass or solid waste co-firing is reduced; when the furnace temperature is lower than the stable combustion requirement or the flame stability decreases, the solid waste pyrolysis gas injection rate is increased, the pulverized coal supply rate is adjusted, or the distribution relationship between the primary and secondary combustion air is adjusted; when nitrogen oxide emissions increase, the reducing gas flow rate is increased or the primary combustion air supply is adjusted; when sulfur- or chlorine-containing pollutant emissions increase, the adsorption and fixation treatment intensity of solid waste pyrolysis gas is increased or the calcium-based adsorption material is replaced.

[0043] In one specific implementation, such as Figure 2 As shown, a biomass co-firing system for preventing coking and corrosion is provided, comprising: The main injection unit includes a pulverized coal conveying channel, a biomass or solid waste raw material conveying channel, a pyrolysis gas injection channel, a primary combustion air channel, and a secondary combustion air channel arranged coaxially from the inside to the outside. These channels are used to convey pulverized coal, biomass or solid waste raw materials, solid waste pyrolysis gas, and staged combustion air, respectively. The outlet ends of the pulverized coal conveying channel, the biomass or solid waste raw material conveying channel, and the pyrolysis gas injection channel are all connected to the combustion mixing zone. The combustion mixing zone is located within the main injection unit and is close to the burner nozzle inlet side. The raw material pretreatment unit is connected to the feed side of the biomass or solid waste raw material conveying channel, and is used to ensure that the biomass or solid waste raw material and coal powder meet the particle size matching requirements. A pyrolysis gas supply unit, connected to the pyrolysis gas injection channel, is used to supply solid waste pyrolysis gas to the combustion mixing zone; The combustion air graded supply unit is connected to the primary combustion air channel and the secondary combustion air channel respectively, and is used to supply primary combustion air to the combustion mixing zone and supply secondary combustion air to the position near the burner nozzle; The anti-coking corrosion unit is located in the burner nozzle area and is used to form a cooling gas film in the burner nozzle area to isolate and capture alkali metal components. A pollution element control unit, connected to the combustion mixing zone and the flow path before the solid waste pyrolysis gas enters the combustion mixing zone, is used to create a local reducing atmosphere and fix sulfur-containing or chlorine-containing components; and The intelligent adjustment unit is connected to the main injection unit, the pyrolysis gas supply unit, the combustion air graded supply unit, the anti-coking and corrosion unit, and the pollutant element regulation unit, respectively, and is used to generate and correct the co-firing control target according to the co-firing control parameters.

[0044] In this embodiment, the main injection unit adopts a central coaxial multi-channel structure. The pulverized coal conveying channel is located in the central area. The biomass or solid waste raw material conveying channel, the pyrolysis gas injection channel, the primary combustion air channel, and the secondary combustion air channel are arranged sequentially around the pulverized coal conveying channel. Each channel is separated by an isolation wall so that the pulverized coal, biomass or solid waste raw material, solid waste pyrolysis gas, primary combustion air, and secondary combustion air are kept in a separate conveying state before entering the preset mixing position.

[0045] Specifically, the combustion mixing zone is a confluence space formed by the outlet ends of the pulverized coal conveying channel, the biomass or solid waste raw material conveying channel, and the pyrolysis gas injection channel. The combustion mixing zone is used to initially mix pulverized coal, biomass or solid waste raw materials, pyrolysis gas from solid waste after adsorption and fixation treatment, and primary combustion air to form a dense-phase mixed combustion gas flow. The combustion mixing zone is located before the burner nozzle inlet side, allowing the mixed combustion gas flow to complete initial combustion organization before entering the nozzle area.

[0046] In one specific embodiment, the raw material pretreatment unit includes at least one of a crushing section, a screening section, and a feeding section, wherein the feeding section is connected to the biomass or solid waste raw material conveying channel; the pyrolysis gas supply unit includes a dispersing injection hole, a micro-orifice nozzle, or an annular injection structure; the outlet of the primary combustion air channel is connected to the combustion mixing zone, and the outlet of the secondary combustion air channel is located between the combustion mixing zone and the burner nozzle inlet side, or located on the burner nozzle inlet side, to supply supplementary combustion gas flow to the periphery of the dense phase mixed combustion gas flow formed by the combustion mixing zone.

[0047] Furthermore, the crushing section is used to reduce the particle size of biomass pellets, solid waste pellets, or solid waste pyrolysis semi-coke; the screening section is used to remove large particles or agglomerates that do not meet the particle size matching requirements; and the feeding section is used to continuously feed the processed biomass or solid waste raw materials into the biomass or solid waste raw material conveying channel. This raw material pretreatment unit can reduce the risk of blockage of solid raw materials in the conveying channel and improve the uniformity of their mixing with pulverized coal.

[0048] Furthermore, the dispersed injection holes, micro-orifice nozzles, or annular injection structures are used to allow the solid waste pyrolysis gas to enter the combustion mixing zone in the form of a diffused flow, annular jet, or multi-point jet. This dispersed injection method reduces flame fluctuations caused by localized enrichment of solid waste pyrolysis gas and improves the mixing uniformity of solid waste pyrolysis gas with pulverized coal, biomass, or solid waste raw materials, as well as primary combustion air.

[0049] In one specific embodiment, the anti-coking corrosion unit includes a cooling gas protection structure and an alkali metal adsorption structure. The cooling gas protection structure is disposed outside the burner nozzle, and the alkali metal adsorption structure is disposed on the inner wall of the burner nozzle or in the furnace near the nozzle area. The pollutant element control unit includes a reducing gas supply structure and a calcium-based sulfur and chlorine fixation structure. The reducing gas supply structure is connected to the combustion mixing zone, and the calcium-based sulfur and chlorine fixation structure is disposed in the flow path before the solid waste pyrolysis gas enters the combustion mixing zone. The intelligent adjustment unit is used to acquire co-firing control parameters and, according to... The co-firing control parameters generate or modify the co-firing control target; the co-firing control parameters include at least one of load matching parameters, fuel adaptation parameters, and nozzle protection feedback parameters; the intelligent adjustment unit includes an operating parameter acquisition unit and a controller, the operating parameter acquisition unit is used to acquire the load demand of the coal-fired unit, the characteristics of biomass or solid waste raw materials, the thermal state of the nozzle, the combustion state, the pollutant emission state, and the coking corrosion trend, the controller is used to adjust the biomass or solid waste co-firing ratio, the solid waste pyrolysis gas injection volume, the combustion air distribution volume, the anti-coking corrosion control volume, and the pollutant element control volume.

[0050] Specifically, the cooling gas protection structure includes a cooling gas supply channel, an annular chamber, and an annular outlet slit or circumferential outlet hole. The cooling gas supply channel communicates with the annular chamber, and the cooling gas flows along the outer wall of the burner nozzle after being discharged through the annular outlet slit or circumferential outlet hole, thereby forming a cooling gas film between the nozzle metal wall and the high-temperature flue gas. The alkali metal adsorption structure includes a coating layer, a liner, an insert-type adsorption carrier, or a porous adsorption structure, and the alkali metal adsorption structure is located in areas where alkali-containing components are prone to reflux or deposition.

[0051] Furthermore, the calcium-based sulfur and chlorine fixation structure includes a supporting shell and a calcium-based adsorbent material disposed within the supporting shell. The supporting shell is provided with a pyrolysis gas inlet and a pyrolysis gas outlet. Solid waste pyrolysis gas enters the supporting shell through the pyrolysis gas inlet, contacts the calcium-based adsorbent material, and then enters the pyrolysis gas injection channel or the combustion mixing zone through the pyrolysis gas outlet. The calcium-based sulfur and chlorine fixation structure can adopt a drawer-type, core-type, or flange-connected disassembly structure to facilitate replacement of the calcium-based adsorbent material after it reaches a preset usage state. The intelligent adjustment unit includes a flow detection component, a temperature detection component, a pressure detection component, a nozzle wall temperature detection component, a pollutant detection component, and a controller. The controller is connected to the pulverized coal feeding mechanism, the biomass or solid waste raw material feeding mechanism, the pyrolysis gas flow adjustment mechanism, the primary combustion air adjustment mechanism, the secondary combustion air adjustment mechanism, the cooling gas adjustment mechanism, and the reducing gas adjustment mechanism, respectively. The controller generates a co-firing control target based on the operating parameters, and provides feedback correction to the co-firing control target when the nozzle thermal state, combustion state, pollutant emission state, or coking corrosion trend deviates from the corresponding preset range.

[0052] In one specific embodiment, a biomass co-firing method for preventing coking and corrosion is provided, applicable to the co-firing of biomass or solid waste in a coal-fired boiler. In this embodiment, the coal-fired unit is operating under variable load conditions, and the fuel includes pulverized coal, biomass pellets, and solid waste pyrolysis gas. The biomass pellets are pretreated and then fed into the burner. The solid waste pyrolysis gas is fed into the combustion mixing zone through the pyrolysis gas injection channel. The burner nozzle area is provided with a cooling gas film forming structure and an alkali metal adsorption layer. A calcium-based sulfur and chlorine fixation structure is provided in the flow path of the pyrolysis gas before it enters the combustion mixing zone.

[0053] In this embodiment, firstly, the following data are obtained: coal-fired unit load demand, pulverized coal supply status, biomass pellet supply status, solid waste pyrolysis gas supply status, furnace combustion status, burner nozzle thermal status, pollutant emission status, and coking corrosion trend. Specifically, the coal-fired unit load demand includes the current load, target load, and load change trend; the pulverized coal supply status includes pulverized coal flow rate and pulverized coal conveying pressure; the biomass pellet supply status includes biomass feed rate, moisture content, particle size distribution, volatile matter, ash content, alkali metal content, sulfur content, and chlorine content; the solid waste pyrolysis gas supply status includes solid waste pyrolysis gas flow rate, pressure, and calorific value; the furnace combustion status includes furnace temperature, flame stability, and flue gas oxygen content; the burner nozzle thermal status includes nozzle wall temperature and nozzle wall temperature change rate; the pollutant emission status includes the emission status of nitrogen oxides, sulfur dioxide, hydrogen chloride, and carbon monoxide; and the coking corrosion trend is determined based on the nozzle wall temperature change rate, channel pressure fluctuations, nozzle area temperature deviation, and changes in alkali and chlorine components in the flue gas.

[0054] Subsequently, co-firing control targets are generated based on the acquired operating parameters. Specifically, when the load demand of the coal-fired unit increases and the furnace temperature is within the preset stable combustion range, the proportion of biomass or solid waste co-firing is increased, and the coal powder supply or solid waste pyrolysis gas injection rate is increased simultaneously; when the alkali metal content, sulfur content, or chlorine content in the biomass particles is high, the instantaneous feed rate of biomass is reduced, and the anti-coking corrosion control rate and pollutant element control rate are increased; when the nozzle wall temperature rises or the coking corrosion trend intensifies, the cooling gas film formation intensity is increased, and the biomass or solid waste co-firing proportion is appropriately reduced; when nitrogen oxide emissions increase, the reducing gas supply rate is increased or the distribution relationship between primary and secondary combustion air is adjusted. Thus, co-firing control targets are formed, including the biomass or solid waste co-firing proportion, coal powder supply rate, solid waste pyrolysis gas injection rate, combustion air distribution rate, anti-coking corrosion control rate, and pollutant element control rate.

[0055] Then, the fuel is diverted and transported according to the aforementioned co-firing control targets. Pulverized coal is fed into the burner via a pulverized coal conveying channel, biomass pellets are fed into the burner via a biomass or solid waste raw material conveying channel, and solid waste pyrolysis gas is fed into the burner via a pyrolysis gas injection channel. Before entering the combustion mixing zone, the biomass pellets are crushed, screened, and graded to match their particle size distribution and ignition characteristics with those of the pulverized coal, thereby reducing the deposition of biomass pellets in the conveying channel or their local enrichment in the combustion mixing zone. Before entering the combustion mixing zone, the solid waste pyrolysis gas flows through a calcium-based sulfur and chlorine fixation structure, allowing the sulfur- and chlorine-containing components in the solid waste pyrolysis gas to contact and be fixed by the calcium-based adsorbent material, before entering the pyrolysis gas injection channel or the combustion mixing zone.

[0056] Next, staged combustion is organized according to the distribution of combustion air. Primary combustion air enters the combustion mixing zone through the primary combustion air channel, mixing with pulverized coal, biomass pellets, and pyrolysis gas from solid waste after adsorption and fixation treatment to form a dense-phase combustion gas flow. Secondary combustion air enters the space between the combustion mixing zone and the burner nozzle inlet side through the secondary combustion air channel, or enters the burner nozzle inlet side, supplying supplementary combustion gas flow to the periphery of the dense-phase combustion gas flow. Through this method, pulverized coal, biomass pellets, pyrolysis gas from solid waste, and combustion air form a staged combustion process within the burner, satisfying the flame root stability requirement while allowing unburned particles and combustible gases to continue burning at the nozzle inlet side or in the nozzle area.

[0057] Specifically, during staged combustion, a locally reducing atmosphere is created in the combustion mixing zone based on the controlled amounts of pollutants. Specifically, reducing gases containing CO or H2 are introduced into the combustion mixing zone, or reducing components from solid waste pyrolysis gas are introduced into the combustion mixing zone, placing the mixing zone of pulverized coal, biomass pellets, and solid waste pyrolysis gas in a locally reducing state with high fuel concentration. Under this state, the conversion pathway of fuel nitrogen is regulated, causing it to convert more towards nitrogen gas, thereby reducing the source generation of nitrogen oxides. Simultaneously, the distribution relationship between the primary and secondary combustion air is matched with the locally reducing atmosphere, maintaining the reducing control effect in the combustion mixing zone and creating supplementary combustion conditions at the burner nozzle inlet side.

[0058] In the burner nozzle area, a nozzle pollution and corrosion control state is established based on the anti-coking corrosion control amount. Specifically, cooling gas is introduced to the outside of the burner nozzle, allowing it to exit through an annular outlet or circumferential outlet and flow along the nozzle metal wall, forming a cooling gas film between the high-temperature flue gas and the nozzle metal wall. Simultaneously, potassium-containing, sodium-containing, or alkali-containing aerosols released during combustion come into contact with and are fixed by an alkali metal adsorption layer located on the inner wall of the burner nozzle or in the furnace near the nozzle area. Through the synergistic effect of the cooling gas film, the alkali metal adsorption layer, and the pre-treatment of solid waste pyrolysis gas for sulfur and chlorine fixation, the impact of high-temperature flue gas scouring, low-melting-point alkali deposition, and sulfur and chlorine corrosion on the burner nozzle is reduced.

[0059] Finally, based on the nozzle pollution and corrosion control status, as well as the corresponding nozzle thermal state, combustion state, pollutant emission status, and coking corrosion trend, the co-firing control target is adjusted through feedback. Specifically, when the nozzle wall temperature or nozzle wall temperature change rate exceeds the corresponding preset threshold, the cooling gas flow rate is increased or the biomass or solid waste co-firing ratio is reduced; when the channel pressure fluctuation increases or the coking corrosion trend intensifies, the anti-coking corrosion control amount is increased, and the biomass pellet feed increase is reduced; when the furnace temperature is lower than the preset stable combustion range or the flame stability decreases, the solid waste pyrolysis gas injection amount is increased or the primary combustion air volume is adjusted; when the nitrogen oxide emission status exceeds the preset emission threshold, the reducing gas supply amount is increased or the combustion air distribution amount is adjusted; when the emission status of sulfur-containing or chlorine-containing components increases, the adsorption and fixation treatment intensity of solid waste pyrolysis gas is increased or the replacement of calcium-based adsorbent material is indicated.

[0060] In this embodiment, pulverized coal, biomass pellets, and solid waste pyrolysis gas do not directly and disorderly mix and burn after entering the burner. Instead, they undergo diversion and transportation, particle size matching, and solid waste pyrolysis gas pretreatment. Then, a staged combustion process is formed through primary and secondary combustion air. Local reducing atmosphere, cooling gas film, alkali metal capture, and sulfur and chlorine fixation regulation are formed in the combustion mixing zone and the burner nozzle zone, respectively. The above operating status is then fed back to the co-firing control target, realizing the linkage correction of the biomass or solid waste co-firing ratio, solid waste pyrolysis gas injection volume, combustion air distribution volume, anti-coking and corrosion regulation volume, and pollutant element regulation volume. This ensures that the combustion process meets the requirements of stable combustion, complete combustion, anti-coking and corrosion, and source control of pollutants.

[0061] In summary, this embodiment has at least the following technical effects: This invention separates and transports pulverized coal, biomass or solid waste raw materials, solid waste pyrolysis gas, primary combustion air, and secondary combustion air, forming a dense-phase mixed combustion airflow in the combustion mixing zone and a supplementary gas flow at the burner nozzle inlet side. This allows different fuel media and combustion air to participate in combustion in a staged manner, which can improve the mixing compatibility between pulverized coal, biomass or solid waste raw materials, and solid waste pyrolysis gas, and reduce the problems of local enrichment, combustion fluctuations, and incomplete combustion caused by direct mixing and combustion. This invention performs particle size matching treatment on biomass or solid waste raw materials before they enter the combustion mixing zone, so that biomass particles, solid waste particles or solid waste pyrolysis semi-coke and coal powder are matched in terms of particle size distribution and ignition characteristics. This can reduce the sedimentation difference and ignition difference between different solid fuels, and improve the uniformity of gas-solid mixing and combustion stability in the combustion mixing zone. This invention enables the adsorption and fixation of sulfur-containing and chlorine-containing components in solid waste pyrolysis gas before it enters the combustion mixing zone. This reduces the proportion of sulfur-containing and chlorine-containing components that directly enter the combustion mixing zone and nozzle area, thereby reducing the risk of corrosion of the burner nozzle and furnace near the nozzle area by sulfur-containing and chlorine-containing components. This invention creates a locally reducing atmosphere in the combustion mixing zone to regulate the fuel nitrogen conversion pathway, thereby increasing the proportion of fuel nitrogen converted to nitrogen gas and reducing the amount of nitrogen oxides generated from the source. At the same time, it works in conjunction with the staged supply of primary and secondary combustion air to balance nitrogen oxide suppression and subsequent burnout requirements. The present invention forms a cooling gas film in the burner nozzle area, allowing the cooling gas to flow along the nozzle metal wall, creating an isolation effect between the high-temperature flue gas and the nozzle metal wall. This reduces the impact of high-temperature flue gas backflow, ash scouring, and local heat load concentration on the nozzle metal wall, thereby reducing the risk of coking and high-temperature corrosion in the nozzle area. This invention captures potassium-containing, sodium-containing, or alkali-containing aerosols released during combustion through an alkali metal adsorption layer, which can reduce the formation of low-melting-point alkali-containing deposits on the inner wall of the burner nozzle or the area near the nozzle in the furnace, and further reduce the risk of coking, ash accumulation, and corrosion in the nozzle area. This invention combines cooling gas film protection, alkali metal capture, solid waste pyrolysis gas sulfur and chlorine fixation, and local reducing atmosphere control, so that the nozzle thermal state, alkali deposition risk, sulfur and chlorine corrosion risk, and nitrogen oxide generation risk are synergistically controlled during the combustion process, avoiding reliance on back-end flue gas purification or a single nozzle cooling measure. This invention provides feedback correction to the co-firing control target based on the nozzle pollution and corrosion control status, as well as the corresponding nozzle thermal state, combustion state, pollutant emission state, and coking corrosion trend. It can adjust the biomass or solid waste co-firing ratio, solid waste pyrolysis gas injection amount, combustion air distribution amount, anti-coking corrosion control amount, and pollutant element control amount in conjunction with changes in unit load, fuel characteristics, and nozzle operating status, thereby improving the burner's adaptability to variable load operation and different co-firing raw materials.

[0062] It is understood that the above embodiments are merely exemplary implementations used to illustrate the principles of the present invention, and the present invention is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A method for preventing coking and corrosion through biomass co-firing, characterized in that, Includes the following steps: S1: Obtain the co-firing control parameters of the coal-fired unit, including load matching parameters, fuel adaptation parameters, and nozzle protection feedback parameters; S2: Generate a blending control target based on the blending control parameters. The blending control target is used to coordinate fuel diversion and transportation, staged combustion, pollutant element regulation and nozzle protection. S3: According to the co-firing control target, pulverized coal, biomass or solid waste raw materials and solid waste pyrolysis gas are separately transported, so that the biomass or solid waste raw materials meet the particle size matching requirements with the pulverized coal before entering the combustion mixing zone, and the solid waste pyrolysis gas completes the adsorption and fixation treatment of sulfur-containing components and chlorine-containing components before entering the combustion mixing zone. S4: According to the co-firing control target, the coal powder after diversion and transportation, the biomass or solid waste raw materials, the solid waste pyrolysis gas after adsorption and fixation treatment and the primary combustion air form a dense phase mixed combustion airflow, and the secondary combustion air forms a supplementary combustion airflow around the dense phase mixed combustion airflow to form a staged combustion process. S5: In accordance with the co-firing control target, based on the fuel enrichment state in the dense phase mixed combustion gas flow, a local reducing atmosphere is formed in the combustion mixing region to regulate the fuel nitrogen conversion pathway; S6: According to the co-firing control target and based on the real-time nozzle thermal state formed by the staged combustion process, a cooling gas film is formed in the burner nozzle area, and the alkali metal components released by combustion are captured by the alkali metal adsorption layer. Combined with the adsorption and fixation results of the sulfur-containing and chlorine-containing components, the nozzle pollution corrosion control state is obtained. S7: Based on the nozzle pollution corrosion control status and the corresponding nozzle protection feedback parameters, the co-firing control target is corrected.

2. The biomass co-firing method for preventing coking and corrosion according to claim 1, characterized in that, The load matching parameters include at least one of the following: coal-fired unit load demand, current load, target load, and load change trend; the fuel matching parameters include at least one of the following: volatile matter, ash content, moisture content, particle size, alkali metal content, sulfur content, and chlorine content; the nozzle protection feedback parameters include at least one of the following: nozzle thermal state, pollutant emission state, and coking corrosion trend.

3. The biomass co-firing method for preventing coking and corrosion according to claim 1, characterized in that, Ensuring that the biomass or solid waste raw material and the pulverized coal meet the particle size matching requirements includes: crushing, screening, or classifying and conveying the biomass particles, solid waste particles, or solid waste pyrolysis semi-coke according to the particle size distribution of the pulverized coal and the ignition characteristics of the biomass or solid waste raw material.

4. The biomass co-firing method for preventing coking and corrosion according to claim 1, characterized in that, The staged combustion process includes: sending the primary combustion air into the combustion mixing zone to form the dense phase combustion airflow; and sending the secondary combustion air between the combustion mixing zone and the burner nozzle inlet side, or into the burner nozzle inlet side, to form the supplementary combustion airflow.

5. The biomass co-firing method for preventing coking and corrosion according to claim 1, characterized in that, The process of forming the nozzle contamination and corrosion control state includes: forming the cooling gas film flowing along the metal wall of the burner nozzle in the burner nozzle area, and contacting and fixing potassium-containing, sodium-containing, or alkali-containing aerosols with the alkali metal adsorption layer.

6. The biomass co-firing method for preventing coking and corrosion according to claim 1, characterized in that, The formation of the local reducing atmosphere includes: introducing a reducing gas containing CO or H2 into the combustion mixing zone, or introducing the reducing components in the solid waste pyrolysis gas into the combustion mixing zone; the sulfur-containing components and the chlorine-containing components are fixed by contacting the calcium-based adsorbent material.

7. The biomass co-firing method for preventing coking corrosion according to any one of claims 1 to 6, characterized in that, Feedback correction of the co-firing control target includes: When the nozzle protection feedback parameter indicates an increased risk of nozzle coking corrosion, the co-firing control target is modified to reduce the proportion of biomass or solid waste co-firing, or to increase the strength of cooling gas film formation. When the staged combustion process fails to meet the stable combustion requirements, the co-firing control target is modified to adjust the solid waste pyrolysis gas injection state or the staged combustion-supporting state. When the nozzle protection feedback parameter indicates that pollutant emissions exceed the preset range, the co-firing control target is corrected to adjust the local reducing atmosphere or to adjust the adsorption and fixation intensity of the sulfur-containing component and the chlorine-containing component.

8. A biomass co-firing system for preventing coking and corrosion, characterized in that, include: The main injection unit includes a pulverized coal conveying channel, a biomass or solid waste raw material conveying channel, a pyrolysis gas injection channel, a primary combustion air channel, and a secondary combustion air channel arranged coaxially from the inside to the outside. These channels are used to convey pulverized coal, biomass or solid waste raw materials, solid waste pyrolysis gas, and staged combustion air, respectively. The outlet ends of the pulverized coal conveying channel, the biomass or solid waste raw material conveying channel, and the pyrolysis gas injection channel are all connected to the combustion mixing zone. The combustion mixing zone is located within the main injection unit and is close to the burner nozzle inlet side. The raw material pretreatment unit is connected to the feed side of the biomass or solid waste raw material conveying channel, and is used to ensure that the biomass or solid waste raw material and coal powder meet the particle size matching requirements. A pyrolysis gas supply unit, connected to the pyrolysis gas injection channel, is used to supply solid waste pyrolysis gas to the combustion mixing zone; The combustion air graded supply unit is connected to the primary combustion air channel and the secondary combustion air channel respectively, and is used to supply primary combustion air to the combustion mixing zone and supply secondary combustion air to the position near the burner nozzle; The anti-coking corrosion unit is located in the burner nozzle area and is used to form a cooling gas film in the burner nozzle area to isolate and capture alkali metal components. A pollution element control unit, connected to the combustion mixing zone and the flow path before the solid waste pyrolysis gas enters the combustion mixing zone, is used to create a local reducing atmosphere and fix sulfur-containing or chlorine-containing components; and The intelligent adjustment unit is connected to the main injection unit, the pyrolysis gas supply unit, the combustion air graded supply unit, the anti-coking and corrosion unit, and the pollutant element regulation unit, respectively, and is used to generate and correct the co-firing control target according to the co-firing control parameters.

9. The biomass co-firing system for preventing coking and corrosion according to claim 8, characterized in that, The raw material pretreatment unit includes at least one of a crushing section, a screening section, and a feeding section, wherein the feeding section is connected to the biomass or solid waste raw material conveying channel; the pyrolysis gas supply unit includes a dispersing injection hole, a micro-orifice nozzle, or an annular injection structure; the outlet of the primary combustion air channel is connected to the combustion mixing zone, and the outlet of the secondary combustion air channel is located between the combustion mixing zone and the burner nozzle inlet side, or located on the burner nozzle inlet side, to supply supplementary combustion gas flow to the periphery of the dense phase mixed combustion gas flow formed by the combustion mixing zone.

10. The biomass co-firing system for preventing coking and corrosion according to claim 8, characterized in that, The anti-coking corrosion unit includes a cooling gas protection structure and an alkali metal adsorption structure. The cooling gas protection structure is located outside the burner nozzle, and the alkali metal adsorption structure is located on the inner wall of the burner nozzle or in the furnace near the nozzle area. The pollutant element control unit includes a reducing gas supply structure and a calcium-based sulfur and chlorine fixation structure. The reducing gas supply structure is connected to the combustion mixing zone, and the calcium-based sulfur and chlorine fixation structure is located in the flow path before the solid waste pyrolysis gas enters the combustion mixing zone. The intelligent adjustment unit is used to acquire blending control parameters and generate or correct the blending control target based on the blending control parameters. The blending control parameters include at least one of load matching parameters, fuel adaptation parameters, and nozzle protection feedback parameters.

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