Flue gas treatment up-to-standard emission method and system under low-load working condition

Abstract

The invention discloses a flue gas treatment up-to-standard emission method and system under a low-load working condition, and the method comprises the steps: introducing flue gas generated under the low-load working condition into a pretreatment unit, and adjusting the combustion atmosphere in a hearth; the residual uncirculated pretreated flue gas is introduced into a denitration unit, an SCR denitration technology is adopted, and the ammonia spraying amount is dynamically adjusted through an intelligent ammonia spraying system according to the NOx concentration in the flue gas, the flue gas flow and the flue gas temperature; the method comprises the following steps: introducing desulfurized flue gas into a deep purification unit through circulating spraying of an absorption liquid and reverse contact of the absorption liquid with the flue gas, removing fine particles with the particle size of less than or equal to 1 mu m through an efficient bag-type dust collector, detecting the deeply purified flue gas in real time, and feeding back to a control system if a detection index does not reach the standard, and adjusting the flue gas recirculation proportion, the ammonia spraying amount and the absorption liquid parameters until the flue gas reaches the standard, and discharging the flue gas through a chimney.

Description

Technical Field

[0001] This invention relates to the field of coal-fired boiler operation control technology, specifically to a method and system for treating flue gas to meet emission standards under low load conditions. Background Technology

[0002] Industrial boilers, incinerators, and other equipment operating under low-load conditions (below 30% of rated load) experience problems such as large fluctuations in flue gas flow, low flue gas temperature (typically below 300℃), and drastic fluctuations in pollutant concentrations. This makes it difficult for existing flue gas treatment systems to consistently meet environmental emission requirements. Specifically, under low-load conditions, the flue gas temperature is below the activity window of the denitrification catalyst, resulting in a significant decrease in denitrification efficiency and increased NO... x Emissions are prone to exceed standards; reduced flue gas flow leads to an imbalance in the liquid-to-gas ratio of the desulfurization system, insufficient contact between the absorbent and flue gas, and reduced SO2 removal efficiency; at the same time, low-temperature flue gas is prone to condensation, which corrodes the treatment equipment, and fine particulate matter is difficult to capture by conventional dust removal equipment, further aggravating the risk of exceeding emission standards.

[0003] Currently, most existing flue gas treatment technologies are designed for rated loads and lack targeted adjustment methods for low-load conditions. Some technologies increase flue gas temperature through additional heating, resulting in excessive energy consumption. Others use fixed ammonia injection rates and fixed circulating flue gas ratios, which cannot cope with parameter fluctuations under low loads, easily leading to problems such as ammonia escape and incomplete pollutant removal. Still others have systems where each treatment unit operates independently, lacking coordinated control, resulting in low overall treatment efficiency and poor stability, making it difficult to meet stringent environmental emission standards. Therefore, developing a flue gas treatment method and system that is adaptable to low-load conditions, has low energy consumption, stable treatment effects, and can achieve compliant emissions has become an urgent technical challenge. Summary of the Invention

[0004] The purpose of this invention is to propose a method and system for treating flue gas to meet emission standards under low-load conditions in order to solve the problems mentioned in the background art.

[0005] To achieve the aforementioned objectives, the first technical solution adopted by this invention is: a method for treating flue gas to meet emission standards under low-load conditions, comprising: S1 introduces the flue gas generated under low load conditions into the pretreatment unit, removes particulate matter with a particle size ≥10μm from the flue gas through cyclone separation, and adjusts the flue gas temperature to 120-180℃ through the preheating component. S2, 15%-40% of the pretreated flue gas is extracted as circulating flue gas, which is pressurized by a high-temperature booster fan to 0.02-0.05MPa higher than the outlet pressure of the secondary hot air header, and mixed with the secondary hot air. After mixing, it is sent into the furnace to participate in combustion and adjust the combustion atmosphere in the furnace. S3 introduces the remaining unrecirculated pretreated flue gas into the denitrification unit, employing SCR denitrification technology. An intelligent ammonia injection system then determines the NO content in the flue gas based on... x The concentration, flue gas flow rate, and flue gas temperature are dynamically adjusted to regulate the ammonia injection rate, controlling the ammonia-nitrogen molar ratio to be 1.0-1.2. S4 introduces the denitrified flue gas into the desulfurization unit and adopts a wet desulfurization process. The absorbent liquid is circulated and sprayed in a counter-current contact with the flue gas. The pH value of the absorbent liquid is controlled at 5.5-6.5 and the liquid-to-gas ratio is 8-12 L / m³ to remove SO2 from the flue gas. S5 introduces the desulfurized flue gas into the deep purification unit, where a high-efficiency bag filter removes fine particulate matter with a particle size ≤1μm, while a low-temperature plasma component removes residual VOCs and trace amounts of harmful gases from the flue gas. S6 performs real-time monitoring of the deeply purified flue gas, including NO. x If the detected indicators such as SO2, particulate matter concentration, flue gas temperature, and humidity do not meet the standards, the feedback is sent to the control system to adjust the flue gas recirculation ratio, ammonia injection volume, and absorbent parameters until the flue gas meets the standards and is then discharged through the chimney.

[0006] Furthermore, the preheating component in step S1 adopts a flue gas waste heat recovery heat exchange structure, which uses the waste heat of the high-temperature flue gas after denitrification to preheat the low-load flue gas before pretreatment, thereby realizing energy recovery and utilization and reducing energy consumption.

[0007] Furthermore, the location for extracting the circulating flue gas in step S2 is the flue between the denitrification reactor and the air preheater. Before extraction, the ash particles in the flue gas are removed by a cyclone separator. The circulating flue gas volume is adjusted by the variable frequency speed of the high-temperature booster fan and the electric regulating valve of the pipeline to ensure that the adjustment accuracy is ≤5%.

[0008] Furthermore, the intelligent ammonia injection system described in step S3 includes NO x Online detection module, ammonia injection flow regulation module and feedback control module, NO x The online detection module collects NO in flue gas in real time. x Concentration, detection frequency ≥ 1 time / minute, ammonia injection flow rate adjustment module dynamically adjusts the opening of ammonia injection gun according to detection data.

[0009] Furthermore, the absorbent in step S4 is a limestone-gypsum slurry with a limestone content of 10% to 15%. Fresh slurry is added in real time during the desulfurization process, while some desulfurization wastewater is discharged and the pH value of the wastewater is controlled to be 6.0-7.0.

[0010] Furthermore, the high-efficiency bag filter described in step S5 adopts a pre-coating ash device, which pre-coats an inert ash layer on the surface of the filter bag during the low-load start-up stage to improve the initial filtration efficiency of the filter bag. At the same time, it adopts a dust removal strategy that combines pulse backflushing and pneumatic conveying.

[0011] Furthermore, the real-time detection described in step S6 uses online monitoring equipment, and the monitoring data is connected to the environmental protection supervision platform. At the same time, a backup detection module is set up. When the main detection module fails, the backup module is immediately activated to ensure continuous detection. If the flue gas fails to meet the standard for 3 consecutive minutes, the system automatically starts the emergency handling procedure, closes the flue gas emission valve, and returns the flue gas to the pretreatment unit for reprocessing.

[0012] To achieve the above-mentioned objectives, the second technical solution adopted by the present invention is: a flue gas treatment and emission compliance system under low load conditions, comprising a processor, a memory, and at least one program, wherein the program is stored in the memory and configured to be executed by the processor, and the program includes instructions for performing a flue gas treatment and emission compliance method under low load conditions.

[0013] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art: 1. High adaptability and stable operation under low load conditions: Through the synergistic effect of flue gas recirculation regulation and preheating components, the inlet flue gas temperature of the denitrification reactor is precisely controlled within the catalyst activity window (320~380℃), solving the problem of decreased denitrification efficiency caused by low flue gas temperature under low load conditions. Simultaneously, through intelligent ammonia injection and dynamic adjustment of absorbent parameters, it adapts to fluctuations in flue gas flow rate and pollutant concentration under low load conditions, ensuring NO... x The emissions of SO2, particulate matter, and other indicators have been consistently met.

[0014] 2. Low energy consumption and energy recovery: The preheating component adopts a flue gas waste heat recovery heat exchange structure, utilizing the waste heat of the high-temperature flue gas after denitrification to preheat the low-load flue gas before pretreatment, eliminating the need for additional energy consumption for heating and effectively reducing system energy consumption; at the same time, the flue gas recirculation design can adjust the furnace combustion atmosphere and reduce NO. x The reduced generation rate lowers the pressure on pollutant treatment at the source, further reducing operating costs.

[0015] 3. High processing efficiency and thorough purification: Utilizing a multi-stage treatment process of "pretreatment-denitrification-desulfurization-deep purification," combined with a high-efficiency bag filter and low-temperature plasma components, it can effectively remove particulate matter of different sizes, SO2, and NO from flue gas. xThe system effectively eliminates residual VOCs, achieving a denitrification efficiency of ≥90%, a desulfurization efficiency of ≥95%, and a particulate matter emission concentration of ≤10mg / m³, meeting current stringent environmental emission requirements. Furthermore, the high-efficiency baghouse dust collector utilizes pre-coating and combined cleaning strategies to prevent filter bag condensation and blockage, extending equipment lifespan.

[0016] 4. High degree of automation and stable and reliable operation: Through bidirectional communication between the control system and each processing unit and the existing boiler DCS system, the automatic coordinated adjustment of flue gas recirculation ratio, ammonia injection amount, absorbent parameters, etc. is realized; a backup detection module and emergency handling procedure are set up to ensure the continuity of detection and the stability of system operation, reduce manual intervention, reduce operation difficulty, and avoid emission exceeding standards due to equipment failure or parameter imbalance.

[0017] 5. Low equipment corrosion and low operation and maintenance costs: The preheating components are treated with anti-corrosion coating, and the circulating flue gas is separated by cyclone separation to remove ash particles before extraction, which can effectively avoid low temperature condensation and ash particles from corroding and wearing the equipment; the structural design of each unit is reasonable, which facilitates inspection and maintenance, and at the same time reduces the occurrence of problems such as ammonia escape and absorbent failure, thereby reducing equipment operation and maintenance costs and environmental risks. Attached Figure Description

[0018] Figure 1 The flowchart of the flue gas treatment method for achieving emission standards under low load conditions provided by an embodiment of the present invention is shown. Detailed Implementation

[0019] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0020] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this application described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or system that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or systems.

[0021] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0022] like Figure 1 As shown, this embodiment of the invention provides a method for achieving emission standards for flue gas treatment under low-load conditions, including: S1 introduces the flue gas generated under low load conditions into the pretreatment unit, removes particulate matter with a particle size ≥10μm from the flue gas through cyclone separation, and adjusts the flue gas temperature to 120-180℃ through the preheating component to avoid equipment corrosion and reduced treatment efficiency caused by low temperature condensation. S2: 15%-40% of the pretreated flue gas is extracted as circulating flue gas, which is pressurized by a high-temperature booster fan to 0.02-0.05 MPa higher than the outlet pressure of the secondary hot air header, and then mixed with secondary hot air. The mixture is then sent into the furnace to participate in combustion, adjusting the combustion atmosphere in the furnace and reducing NO. x The amount of generated is increased, and the flue gas temperature at the inlet of the denitrification reactor is raised to the catalyst activity window (320-380℃). S3 introduces the remaining unrecirculated pretreated flue gas into the denitrification unit, employing SCR denitrification technology. An intelligent ammonia injection system then determines the NO content in the flue gas based on... x The concentration, flue gas flow rate, and flue gas temperature are dynamically adjusted to regulate the ammonia injection rate, controlling the ammonia-nitrogen molar ratio to 1.0-1.2 to ensure a denitrification efficiency of ≥90%. S4 introduces the denitrified flue gas into the desulfurization unit, employing a wet desulfurization process. The absorbent liquid is circulated and sprayed in a counter-current manner with the flue gas. The pH value of the absorbent liquid is controlled at 5.5-6.5, and the liquid-to-gas ratio is 8-12 L / m³. This process removes SO2 from the flue gas and ensures a desulfurization efficiency of ≥95%. S5 introduces the desulfurized flue gas into the deep purification unit, where a high-efficiency bag filter removes fine particulate matter with a particle size ≤1μm, while a low-temperature plasma component removes residual VOCs and trace amounts of harmful gases from the flue gas, ensuring that the particulate matter emission concentration is ≤10mg / m³. S6 performs real-time monitoring of the deeply purified flue gas, including NO. x If the detected indicators such as SO2, particulate matter concentration, flue gas temperature, and humidity do not meet the standards, the feedback is sent to the control system to adjust the flue gas recirculation ratio, ammonia injection volume, and absorbent parameters until the flue gas meets the standards and is then discharged through the chimney.

[0023] According to an embodiment of the present invention, the preheating component in step S1 adopts a flue gas waste heat recovery heat exchange structure, which uses the waste heat of the high-temperature flue gas after denitrification to preheat the low-load flue gas before pretreatment, thereby realizing energy recovery and utilization and reducing energy consumption.

[0024] According to an embodiment of the present invention, the location for extracting the circulating flue gas in step S2 is the flue between the denitrification reactor and the air preheater. Before extraction, the ash particles in the flue gas are removed by a cyclone separator. The circulating flue gas volume is adjusted by the variable frequency speed of the high-temperature booster fan and the electric regulating valve of the pipeline to ensure that the adjustment accuracy is ≤5%.

[0025] According to an embodiment of the present invention, the intelligent ammonia injection system in step S3 includes NO x Online detection module, ammonia injection flow regulation module and feedback control module, NO x The online detection module collects NO in flue gas in real time. x Concentration, detection frequency ≥ 1 time / minute, ammonia injection flow rate adjustment module dynamically adjusts the opening of ammonia injection gun according to detection data.

[0026] According to an embodiment of the present invention, the absorbent in step S4 is a limestone-gypsum slurry with a limestone content of 10% to 15%. Fresh slurry is added in real time during the desulfurization process, while some desulfurization wastewater is discharged and the pH value of the wastewater is controlled to be 6.0-7.0.

[0027] According to an embodiment of the present invention, in step S5, the high-efficiency bag filter adopts a pre-coating ash device, which pre-coats an inert ash layer on the surface of the filter bag during the low-load start-up stage to improve the initial filtration efficiency of the filter bag. At the same time, a dust removal strategy combining pulse backflushing and pneumatic conveying is adopted.

[0028] According to an embodiment of the present invention, in step S6, real-time detection uses online monitoring equipment, and the monitoring data is connected to the environmental protection supervision platform. At the same time, a backup detection module is set up. When the main detection module fails, the backup module is immediately activated to ensure continuous detection. If the flue gas fails to meet the standard for 3 consecutive minutes, the system automatically starts the emergency handling procedure, closes the flue gas emission valve, and returns the flue gas to the pretreatment unit for reprocessing.

[0029] According to an embodiment of the present invention, the separation efficiency of the cyclone separator in step S1 is ≥90%, and the pressure difference between its inlet and outlet is controlled at 500-800Pa to avoid excessive pressure difference from obstructing the flow of flue gas.

[0030] In the S3 SCR denitrification reactor, the catalyst module is arranged in two layers with a spacing of 0.8-1.2m between the two layers, which facilitates catalyst replacement and maintenance, and improves the uniformity of the denitrification reaction.

[0031] After treatment by the low-temperature plasma component in step S5, the residual VOCs concentration in the flue gas is ≤10mg / m³, which meets the VOCs emission limit requirements.

[0032] To achieve the above-mentioned objectives, the second technical solution adopted by the present invention is: a flue gas treatment and emission compliance system under low load conditions, comprising a processor, a memory, and at least one program, wherein the program is stored in the memory and configured to be executed by the processor, and the program includes instructions for performing a flue gas treatment and emission compliance method under low load conditions.

[0033] In summary, the present invention has the following advantages compared with the prior art: 1. High adaptability and stable operation under low load conditions: Through the synergistic effect of flue gas recirculation regulation and preheating components, the inlet flue gas temperature of the denitrification reactor is precisely controlled within the catalyst activity window (320-380℃), solving the problem of decreased denitrification efficiency caused by low flue gas temperature under low load conditions. Simultaneously, through intelligent ammonia injection and dynamic adjustment of absorbent parameters, it adapts to fluctuations in flue gas flow rate and pollutant concentration under low load conditions, ensuring NO... x The emissions of SO2, particulate matter, and other indicators have been consistently met.

[0034] 2. Low energy consumption and energy recovery: The preheating component adopts a flue gas waste heat recovery heat exchange structure, utilizing the waste heat of the high-temperature flue gas after denitrification to preheat the low-load flue gas before pretreatment, eliminating the need for additional energy consumption for heating and effectively reducing system energy consumption; at the same time, the flue gas recirculation design can adjust the furnace combustion atmosphere and reduce NO. x The reduced generation rate lowers the pressure on pollutant treatment at the source, further reducing operating costs.

[0035] 3. High processing efficiency and thorough purification: Utilizing a multi-stage treatment process of "pretreatment-denitrification-desulfurization-deep purification," combined with a high-efficiency bag filter and low-temperature plasma components, it can effectively remove particulate matter of different sizes, SO2, and NO from flue gas. x The system effectively eliminates residual VOCs, achieving a denitrification efficiency of ≥90%, a desulfurization efficiency of ≥95%, and a particulate matter emission concentration of ≤10mg / m³, meeting current stringent environmental emission requirements. Furthermore, the high-efficiency baghouse dust collector utilizes pre-coating and combined cleaning strategies to prevent filter bag condensation and blockage, extending equipment lifespan.

[0036] 4. High degree of automation and stable and reliable operation: Through bidirectional communication between the control system and each processing unit and the existing boiler DCS system, the automatic coordinated adjustment of flue gas recirculation ratio, ammonia injection amount, absorbent parameters, etc. is realized; a backup detection module and emergency handling procedure are set up to ensure the continuity of detection and the stability of system operation, reduce manual intervention, reduce operation difficulty, and avoid emission exceeding standards due to equipment failure or parameter imbalance.

[0037] 5. Low equipment corrosion and low operation and maintenance costs: The preheating components are treated with anti-corrosion coating, and the circulating flue gas is separated by cyclone separation to remove ash particles before extraction, which can effectively avoid low temperature condensation and ash particles from corroding and wearing the equipment; the structural design of each unit is reasonable, which facilitates inspection and maintenance, and at the same time reduces the occurrence of problems such as ammonia escape and absorbent failure, thereby reducing equipment operation and maintenance costs and environmental risks.

[0038] Those skilled in the art will understand that, for ease of explanation, the example is provided with one memory and one processor. In actual terminals or servers, multiple processors and memories may exist. Memory can also be referred to as storage medium or storage device, etc., and the embodiments of this application do not limit this.

[0039] It should be understood that in the embodiments of this application, the processor may be a Central Processing Unit (CPU), or it may be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The processor may also be a general-purpose microprocessor, graphics processing unit (GPU), or one or more integrated circuits to execute relevant programs to achieve the functions required by the embodiments of this application.

[0040] The processor can also be an integrated circuit chip with signal processing capabilities. In implementation, each step of this application can be completed through integrated logic circuits in the processor hardware or instructions in software form. The aforementioned processor can implement or execute the methods, steps, and logic block diagrams disclosed in the embodiments of this application. The steps of the methods disclosed in the embodiments of this application can be directly manifested as execution by a hardware decoding processor, or execution by a combination of hardware and software modules in the decoding processor. The software modules can reside in random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, registers, or other mature storage media in the art. This storage medium is located in memory; the processor reads information from the memory and, in conjunction with its hardware, completes the functions required by the units included in the methods, systems, and storage media of the embodiments of this application.

[0041] It should also be understood that the memory mentioned in the embodiments of this application can be volatile memory or non-volatile memory, or may include both volatile and non-volatile memory. Non-volatile memory can be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory. Volatile memory can be random access memory (RAM), which is used as an external cache.

[0042] By way of example, but not limitation, many forms of RAM are available, such as Static Random Access Memory (SRAM), Dynamic Random Access Memory (DRAM), Synchronous DRAM (SDRAM), Double Data Rate SDRAM (DDR SDRAM), Enhanced Synchronous DRAM (ESDRAM), Synchlink DRAM (SLDRAM), and Direct Rambus RAM (DR RAM).

[0043] The memory can also be a Compact Disc Read-Only Memory (CD-ROM) or other optical disc storage, optical disk storage (including compressed optical discs, laser discs, optical discs, digital universal optical discs, Blu-ray discs, etc.), magnetic disk storage media, or other magnetic storage devices, or any other medium capable of carrying or storing desired program code in the form of instructions or data structures that can be accessed by a computer, but is not limited thereto. The memory can exist independently and be connected to the processor via a bus. The memory can also be integrated with the processor. The memory can store programs, and when the program stored in the memory is executed by the processor, the processor performs the various steps of the method determined in the above embodiments of this application.

[0044] It should be noted that when the processor is a general-purpose processor, DSP, ASIC, FPGA, or other programmable logic device, discrete gate or transistor logic device, or discrete hardware component, the memory (storage module) is integrated into the processor. It should be noted that the memory described herein is intended to include, but is not limited to, these and any other suitable types of memory.

[0045] It should be understood that the term "and / or" in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0046] In implementation, each step of the above method can be completed by integrated logic circuits in the processor's hardware or by instructions in software. The steps of the method disclosed in the embodiments of this application can be directly implemented by a hardware processor, or by a combination of hardware and software modules within the processor. The software modules can reside in mature storage media in the art, such as random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, or registers. Since this storage medium is located in memory, the processor reads information from the memory and, in conjunction with its hardware, completes the steps of the above method; to avoid repetition, these will not be described in detail here.

[0047] Those skilled in the art will recognize that the various illustrative logical blocks (ILBs) and steps described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this application.

[0048] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented in software, it can be implemented, in whole or in part, as a computer-programmed program product. A computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a processor, all or part of the flow or function according to the embodiments of this application is generated. The computer can be a general-purpose computer, a computer network, or other programmable device.

[0049] This embodiment also provides a computer-readable storage medium storing a computer program that causes a computer to execute in order to implement the above-described method based on multi-stage vortex and intelligent feedforward.

[0050] It should be noted that computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, computer instructions can be transmitted from one website, computer, server, or data center to another via wired (e.g., coaxial cable, fiber optic) or wireless (e.g., infrared, wireless, microwave, etc.) means, or from one website, computer, server, or data center to a mobile phone processor via a wired means. A computer-readable storage medium can be any usable medium that a computer can access, or a data storage system such as a server or data center that integrates one or more usable media. Usable media can be magnetic media (e.g., floppy disks, hard disks), optical media (e.g., DVDs), or semiconductor media (e.g., solid-state drives), etc.

[0051] Finally, it should be noted that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for treating flue gas to achieve emission standards under low-load conditions, characterized in that, include: S1 introduces the flue gas generated under low load conditions into the pretreatment unit, removes particulate matter with a particle size ≥10μm from the flue gas through cyclone separation, and adjusts the flue gas temperature to 120-180℃ through the preheating component. S2, 15%-40% of the pretreated flue gas is extracted as circulating flue gas, which is pressurized by a high-temperature booster fan to 0.02-0.05MPa higher than the outlet pressure of the secondary hot air header, and mixed with the secondary hot air. After mixing, it is sent into the furnace to participate in combustion and adjust the combustion atmosphere in the furnace. S3 introduces the remaining unrecirculated pretreated flue gas into the denitrification unit, employing SCR denitrification technology. An intelligent ammonia injection system then determines the NO content in the flue gas based on... x The concentration, flue gas flow rate, and flue gas temperature are dynamically adjusted to regulate the ammonia injection rate, controlling the ammonia-nitrogen molar ratio to be 1.0-1.

2. S4 introduces the denitrified flue gas into the desulfurization unit and adopts a wet desulfurization process. The absorbent liquid is circulated and sprayed in a counter-current contact with the flue gas. The pH value of the absorbent liquid is controlled at 5.5-6.5 and the liquid-to-gas ratio is 8-12 L / m³ to remove SO2 from the flue gas. S5 introduces the desulfurized flue gas into the deep purification unit, where a high-efficiency bag filter removes fine particulate matter with a particle size ≤1μm, while a low-temperature plasma component removes residual VOCs and trace amounts of harmful gases from the flue gas. S6 performs real-time monitoring of the deeply purified flue gas, including NO. x If the detected indicators such as SO2, particulate matter concentration, flue gas temperature, and humidity do not meet the standards, the feedback is sent to the control system to adjust the flue gas recirculation ratio, ammonia injection volume, and absorbent parameters until the flue gas meets the standards and is then discharged through the chimney.

2. The method for achieving emission standards for flue gas treatment under low-load conditions as described in claim 1, characterized in that, The preheating component described in step S1 adopts a flue gas waste heat recovery heat exchange structure, which uses the waste heat of the high-temperature flue gas after denitrification to preheat the low-load flue gas before pretreatment, thereby realizing energy recovery and utilization and reducing energy consumption.

3. The method for achieving emission standards for flue gas treatment under low-load conditions as described in claim 2, characterized in that, The location for extracting the circulating flue gas in step S2 is the flue between the denitrification reactor and the air preheater. Before extraction, the flue gas is first removed by a cyclone separator to remove ash particles. The circulating flue gas volume is adjusted by the variable frequency speed of the high-temperature booster fan and the electric regulating valve of the pipeline to ensure that the adjustment accuracy is ≤5%.

4. The method for achieving emission standards for flue gas treatment under low-load conditions as described in claim 3, characterized in that, The intelligent ammonia injection system mentioned in step S3 includes NO x Online detection module, ammonia injection flow regulation module and feedback control module, NO x The online detection module collects NO in flue gas in real time. x Concentration, detection frequency ≥ 1 time / minute, ammonia injection flow rate adjustment module dynamically adjusts the opening of ammonia injection gun according to detection data.

5. The method for achieving emission standards for flue gas treatment under low-load conditions as described in claim 4, characterized in that, The absorbent in step S4 is a limestone-gypsum slurry with a limestone content of 10%-15%. Fresh slurry is added in real time during the desulfurization process, while some desulfurization wastewater is discharged and the pH value of the wastewater is controlled to be 6.0-7.

0.

6. The method for achieving emission standards for flue gas treatment under low-load conditions as described in claim 4, characterized in that, The high-efficiency bag filter described in step S5 uses a pre-coating ash device to pre-coat an inert ash layer on the surface of the filter bag during the low-load start-up phase, thereby improving the initial filtration efficiency of the filter bag. At the same time, it adopts a dust removal strategy that combines pulse backflushing and pneumatic conveying.

7. The method for achieving emission standards for flue gas treatment under low-load conditions as described in claim 1, characterized in that, The real-time detection described in step S6 uses online monitoring equipment, and the monitoring data is connected to the environmental protection supervision platform. At the same time, a backup detection module is set up. When the main detection module fails, the backup module is immediately activated to ensure continuous detection. If the flue gas fails to meet the standard for 3 consecutive minutes, the system automatically starts the emergency handling procedure, closes the flue gas emission valve, and returns the flue gas to the pretreatment unit for reprocessing.

8. A flue gas treatment and emission standard compliance system under low load conditions, characterized in that, It includes a processor, a memory, and at least one program, the program being stored in the memory and configured to be executed by the processor, the program including instructions for performing a method for achieving emission standards under low-load conditions as described in any one of claims 1-7.

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