A high-efficiency low-emission coal-fired power generation system and method based on dual combustion

Abstract

The embodiment of the present disclosure provides a high-efficiency low-emission coal-fired power generation system based on double combustion, comprising: a double combustion boiler provided with a main combustion zone for burning pulverized coal and an auxiliary combustion zone arranged upstream of the main combustion zone and used for burning auxiliary fuel; a combustion control system used for monitoring combustion conditions of the main combustion zone and the auxiliary combustion zone and adjusting an auxiliary fuel supply amount; and an emission treatment system arranged in a flue of the double combustion boiler and used for purifying flue gas generated by the double combustion boiler.

Description

Technical Field

[0001] The embodiments disclosed herein belong to the field of coal-fired power generation technology, specifically relating to a high-efficiency, low-emission coal-fired power generation system and method based on dual combustion. Background Technology

[0002] Currently, coal-fired power generation remains an important part of the global energy supply, but the emissions of carbon dioxide, sulfur dioxide, and nitrogen oxides generated during the coal-fired power generation process seriously affect the environment.

[0003] To meet increasingly stringent environmental protection requirements, traditional coal-fired power generating units face the dual challenges of improving combustion efficiency and reducing pollution emissions. Existing technologies mainly focus on optimizing pulverized coal combustion and employing desulfurization and denitrification equipment. However, these technologies have limitations in improving efficiency and reducing emissions, and have not yet fully resolved the dual issues of improving overall efficiency and reducing pollutant emissions in coal-fired power generating units.

[0004] Therefore, how to solve the above problems has become a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] The embodiments disclosed herein aim to at least solve one of the technical problems existing in the prior art, and provide a high-efficiency, low-emission coal-fired power generation system and method based on dual combustion.

[0006] A first aspect of the embodiments of this disclosure provides a high-efficiency, low-emission coal-fired power generation system based on dual combustion, comprising: A dual-combustion boiler is provided with a main combustion zone for burning pulverized coal and an auxiliary combustion zone located upstream of the main combustion zone for burning auxiliary fuel; A combustion control system is used to monitor the combustion conditions of the main combustion zone and the auxiliary combustion zone, and to adjust the auxiliary fuel supply. An emission treatment system is installed in the flue of the dual-combustion boiler to purify the flue gas generated by the dual-combustion boiler.

[0007] Furthermore, it also includes: heat exchange components and economizers installed in the flue of the dual-combustion boiler.

[0008] Optionally, the heat exchange assembly includes a screen-type superheater, a high-temperature superheater, a high-temperature reheater, a first low-temperature reheater, and a low-temperature superheater, which are arranged sequentially along the flue gas flow direction within the flue of the dual-combustion boiler.

[0009] Furthermore, it also includes: a second low-temperature reheater disposed in the flue of the dual-combustion boiler, wherein the second low-temperature reheater is configured to heat the boiler feedwater and transport the heated boiler feedwater to the feedwater inlet of the dual-combustion boiler through a feedwater pipeline.

[0010] Optionally, the emission treatment system includes a selective catalytic reduction (SCR) device configured to denitrify or desulfurize the flue gas generated by the dual-combustion boiler.

[0011] Furthermore, it also includes: an air preheater located at the flue outlet of the dual-combustion boiler and arranged downstream of the emission treatment system; The hot primary air outlet of the air preheater is connected to the pulverized coal tank connected to the main combustion zone via a primary air duct, and the hot secondary air outlet of the air preheater is connected to the main combustion zone via a secondary air duct.

[0012] Furthermore, it also includes: a fuel tank connected to the auxiliary combustion zone via a pipeline and used for storing auxiliary fuel, and an auxiliary burner disposed in the auxiliary combustion zone for mixing and burning the auxiliary fuel with air.

[0013] Optionally, the combustion control system is configured to adjust the combustion ratio of the auxiliary fuel to pulverized coal according to the unit load.

[0014] A second aspect of the embodiments of this disclosure provides a method for high-efficiency, low-emission coal-fired power generation based on dual combustion, the method being implemented according to the system described above, comprising: In the dual-combustion boiler, pulverized coal is burned in the main combustion zone, while auxiliary fuel is burned in the auxiliary combustion zone. The combustion conditions of the main combustion zone and the auxiliary combustion zone are monitored in real time, and the auxiliary fuel supply is adjusted accordingly. The flue gas generated from combustion in the main combustion zone and the auxiliary combustion zone is purified.

[0015] Furthermore, it also includes: heat exchange between the high-temperature flue gas generated by combustion and the heat exchange component and the economizer.

[0016] The beneficial effects of the embodiments of this disclosure include: In this application, by adding an auxiliary combustion zone to the boiler and having it work in conjunction with the main pulverized coal combustion zone, the overall thermal efficiency of the combustion process can be significantly improved. The introduction of auxiliary fuel increases the local combustion temperature, promotes the complete combustion of pulverized coal, and thus directly reduces fuel consumption and the amount of unburned carbon residue.

[0017] Furthermore, this application employs a dual configuration of a main combustion zone and an auxiliary combustion zone, which effectively improves combustion efficiency and suppresses the generation of harmful gases such as nitrogen oxides (NOx) during combustion. On the other hand, the emission treatment system of this application performs deep purification of the flue gas, ensuring that the final emissions meet stringent environmental standards. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of a high-efficiency, low-emission coal-fired power generation system based on dual combustion, according to an embodiment of this disclosure. Figure 2 This is a schematic flowchart of another embodiment of the present disclosure of a high-efficiency, low-emission coal-fired power generation method based on dual combustion.

[0019] In the diagram, 1. Dual-combustion boiler; 2. Emission treatment system; 3. Heat exchange components; 4. Economizer; 5. Feedwater pipeline; 6. Primary air pipeline; 7. Secondary air pipeline; 8. Pulverized coal tank; 9. Fuel tank; 10. Air preheater; 11. Main combustion zone; 12. Auxiliary combustion zone; 13. Flue; 31. Screen-type superheater; 32. High-temperature superheater; 33. High-temperature reheater; 34. First low-temperature reheater; 35. Low-temperature superheater; 36. Second low-temperature reheater. Detailed Implementation

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

[0021] The embodiments of this application will be further described in detail below with reference to the accompanying drawings and examples. The detailed descriptions and accompanying drawings of the following embodiments are used to exemplarily illustrate the principles of this application, but should not be used to limit the scope of this application; that is, this application is not limited to the described embodiments. In the description of this application, it should be noted that, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," "outer," etc., indicating orientation or positional relationships are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. "Vertical" is not strictly vertical, but within the allowable error range. "Parallel" is not strictly parallel, but within the allowable error range.

[0022] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this application depending on the specific circumstances.

[0023] The purpose of this invention is to provide a high-efficiency, low-emission coal-fired power generation system and method based on dual combustion technology. By improving the coal combustion process, the system significantly improves combustion efficiency and reduces emissions of harmful gases, especially nitrogen oxides, providing an effective technical solution for the green upgrading of coal-fired power units.

[0024] like Figure 1 As shown, a high-efficiency, low-emission coal-fired power generation system based on dual combustion includes a dual combustion boiler 1, a combustion control system, and an emission treatment system 2.

[0025] The dual-combustion boiler 1 is provided with a main combustion zone 11 for burning pulverized coal and an auxiliary combustion zone 12 located upstream of the main combustion zone 11 for burning auxiliary fuel.

[0026] The combustion control system is used to monitor the combustion conditions of the main combustion zone 11 and the auxiliary combustion zone 12, and to adjust the auxiliary fuel supply.

[0027] The emission treatment system 2 is installed in the flue 13 of the dual-combustion boiler 1 and is used to purify the flue gas generated by the dual-combustion boiler 1.

[0028] In some embodiments, the auxiliary fuel includes natural gas or liquid fuel.

[0029] In this application, by adding an auxiliary combustion zone 12 to the boiler and having it work in conjunction with the main pulverized coal combustion zone 11, the overall thermal efficiency of the combustion process can be significantly improved. The introduction of auxiliary fuel increases the local combustion temperature, promotes the complete combustion of pulverized coal, and thus directly reduces fuel consumption and the amount of unburned carbon residue.

[0030] Furthermore, this application employs a dual configuration of a main combustion zone 11 and an auxiliary combustion zone 12, which effectively improves combustion efficiency and suppresses the generation of harmful gases such as nitrogen oxides (NOx) during combustion. On the other hand, the emission treatment system 2 of this application performs deep purification treatment on the flue gas, ensuring that the final emissions meet stringent environmental standards.

[0031] In some embodiments, the system also includes a heat exchange assembly 3 and an economizer 4 disposed within the flue 13 of the dual-combustion boiler 1.

[0032] In this application, by adding an auxiliary combustion zone 12 to co-fire coal with the main combustion zone 11, and by using heat exchange components 3 and economizer 4 to recover waste heat from flue gas, the overall thermal efficiency of the power generation system can be significantly improved, and fuel consumption and pollutant emissions can be reduced.

[0033] In some embodiments, the heat exchange assembly 3 includes a screen-type superheater 31, a high-temperature superheater 32, a high-temperature reheater 33, a first low-temperature reheater 34, and a low-temperature superheater 35 arranged sequentially along the flue gas flow direction within the flue 13 of the dual-combustion boiler 1.

[0034] In this application, by adding an auxiliary combustion zone 12 upstream of the main combustion zone 11 to improve combustion efficiency, and configuring a complete flue gas heat recovery system consisting of multi-stage superheaters and reheaters, it is possible to significantly improve thermal energy and power generation efficiency.

[0035] In some embodiments, the system further includes a second low-temperature reheater 36 disposed in the flue 13 of the dual-combustion boiler 1, wherein the second low-temperature reheater 36 is configured to heat the boiler feedwater and transport the heated boiler feedwater to the feedwater inlet of the dual-combustion boiler 1 through the feedwater pipeline 5.

[0036] In this application, a second low-temperature reheater 36 is added to heat the boiler feedwater in order to recover the waste heat of low-grade flue gas, thereby achieving deep utilization of the total thermal energy of the system and further improving the cycle efficiency.

[0037] In some embodiments, the emission treatment system 2 includes a selective catalytic reduction (SCR) device configured to denitrify or desulfurize the flue gas generated by the dual-combustion boiler 1.

[0038] In this application, by configuring a selective catalytic reduction (SCR) device in the flue 13, the flue gas after high-efficiency combustion can be subjected to deep denitrification or desulfurization treatment to ensure that the final emissions meet strict environmental protection standards.

[0039] In some embodiments, it further includes an air preheater 10 located at the flue outlet of the flue 13 of the dual-combustion boiler 1 and arranged downstream of the emission treatment system 2.

[0040] The hot primary air outlet of the air preheater 10 is connected to the pulverized coal tank 8, which is connected to the main combustion zone 11, via the primary air duct 6, and the hot secondary air outlet of the air preheater 10 is connected to the main combustion zone 11 via the secondary air duct 7.

[0041] In this application, by configuring an air preheater 10, the waste heat of the flue gas after emission treatment can be used to preheat the primary and secondary air sent to the boiler for combustion, thereby further improving the thermal efficiency of the boiler and reducing fuel consumption.

[0042] In some embodiments, the system further includes: a fuel tank 9 connected to the auxiliary combustion zone 12 via a pipeline and used for storing auxiliary fuel; and an auxiliary burner disposed within the auxiliary combustion zone 12 for mixing and burning the auxiliary fuel with air.

[0043] In this application, by configuring fuel tank 9 and auxiliary burner, a stable supply and efficient combustion of auxiliary fuel are ensured, thereby enhancing the temperature boosting effect on the main combustion zone 11 and the stability of system operation.

[0044] In some embodiments, the combustion control system is configured to adjust the combustion ratio of the auxiliary fuel to pulverized coal according to the unit load.

[0045] In this application, the combustion control system adjusts the ratio of main and auxiliary fuels in real time according to the unit load, thereby achieving flexible, efficient and stable operation of the system, maximizing combustion efficiency and adapting to load changes.

[0046] refer to Figure 2 A second aspect of the embodiments of this disclosure provides a method for high-efficiency, low-emission coal-fired power generation based on dual combustion, the method being implemented according to the system described above, comprising: S101 In the dual-combustion boiler 1, pulverized coal is burned in the main combustion zone 11, while auxiliary fuel is burned in the auxiliary combustion zone 12.

[0047] S102. Monitor the combustion conditions of the main combustion zone 11 and the auxiliary combustion zone 12 in real time, and adjust the auxiliary fuel supply.

[0048] S103. The flue gas generated by combustion in the main combustion zone 11 and the auxiliary combustion zone 12 is purified.

[0049] In this application, efficiency is improved by coordinating the combustion of primary and auxiliary fuels and controlling the combustion state in real time to deeply purify the products, thereby achieving efficient, low-emission and stable operation of the coal-fired power generation process.

[0050] In some embodiments, the method further includes: exchanging heat between the high-temperature flue gas generated by combustion and the heat exchange component 3 and the economizer 4.

[0051] In this application, waste heat from flue gas is recovered through heat exchange component 3 and economizer 4, thereby improving the overall thermal efficiency of the system.

[0052] Specifically, attached Figure 1 A structural diagram of a coal-fired power generation system based on dual combustion technology, according to the present invention, is shown. This system improves combustion efficiency and reduces harmful gas emissions by introducing auxiliary fuel during pulverized coal combustion. (Attached) Figure 1 The components and workflows are described below: This invention modifies the combustion system of a traditional coal-fired power plant boiler by adopting a "dual combustion" technology, which involves adding auxiliary fuel to the auxiliary combustion zone 12 above the main combustion zone 11 of pulverized coal to improve the combustion efficiency of pulverized coal, reduce the residual carbon content of coal, and optimize combustion conditions to reduce the emission of harmful substances in coal gas.

[0053] Specifically, the auxiliary fuel is a liquid fuel or natural gas, which has a high calorific value. The auxiliary fuel is burned together with the pulverized coal, providing a higher local temperature under the original combustion temperature and pressure, thus promoting the complete combustion of the pulverized coal. Furthermore, by setting an auxiliary burner in the auxiliary combustion zone 12 and regulating the temperature distribution of the main combustion zone 11 and the auxiliary combustion zone 12 through the combustion control system, the generation of harmful gases, especially nitrogen oxides (NOx), is further reduced.

[0054] The coal-fired power generation system of the present invention includes: The dual-combustion boiler 1 is equipped with a main combustion zone 11 and an auxiliary combustion zone 12. The auxiliary combustion zone 12 improves the combustion efficiency of pulverized coal by burning auxiliary fuels such as liquid fuels or natural gas.

[0055] The combustion control system, including the temperature and pressure control systems for the main combustion and auxiliary combustion, is used to monitor and adjust the heat and gas emissions during the combustion process in real time to ensure optimal combustion efficiency.

[0056] Emission treatment system 2 includes denitrification and desulfurization devices, and is combined with low-NOx combustion technology and carbon dioxide capture devices to effectively reduce harmful gas emissions. Specifically, emission treatment system 2 is a selective catalytic reduction device.

[0057] Among them, the combustion control system can automatically adjust the supply of auxiliary fuel according to different loads and operating conditions, ensuring that the synergistic combustion of pulverized coal and auxiliary fuel is always kept in the best state, so as to improve the overall thermal efficiency of the coal-fired power generation system.

[0058] Furthermore, the pulverized coal and air are burned in the main combustion zone 11. Specifically, the pulverized coal is injected into the main combustion zone 11 of the furnace through the burner, and mixes with air and burns under high temperature conditions, releasing heat.

[0059] The auxiliary combustion zone 12 is located upstream of the main combustion zone 11 and is used to burn auxiliary fuel. The auxiliary fuel can be a liquid fuel (such as diesel) or gasified coal gas, etc. The combustion efficiency of pulverized coal is improved by burning the auxiliary fuel in the auxiliary combustion zone 12 to provide additional combustion heat.

[0060] The coal-fired power generation system of this application also includes an auxiliary fuel input pipeline for introducing auxiliary fuel from fuel tank 9 into auxiliary combustion zone 12. Specifically, the auxiliary fuel enters auxiliary combustion zone 12 via a gas or liquid conveying system and combusts in conjunction with the main combustion zone 11. The addition of auxiliary fuel helps to increase the local temperature, thereby promoting the complete combustion of pulverized coal.

[0061] An auxiliary burner is installed in the auxiliary combustion zone 12. Auxiliary fuel is mixed with air and ignited after passing through the auxiliary burner, providing additional heat energy. This application employs this configuration, which can effectively improve combustion efficiency and reduce residual carbon and unburned materials in the coal.

[0062] The combustion process of this application includes: When the main combustion zone 11 and the auxiliary combustion zone 12 work together, the additional heat provided by the auxiliary combustion zone 12 helps the main combustion zone 11 achieve more efficient pulverized coal combustion. This application, through the coordinated combustion of the main combustion zone 11 and the auxiliary combustion zone 12, increases the combustion temperature of the pulverized coal, resulting in more complete combustion and reducing the amount of residual carbon in the pulverized coal.

[0063] Furthermore, the hot gas flow generated after the pulverized coal is burned in the main combustion zone 11 will flow to other parts of the boiler (such as the superheater, reheater, etc.). The hot gas flow in the auxiliary combustion zone 12 mixes with the main combustion gas flow, further improving combustion efficiency and heat transfer efficiency.

[0064] Furthermore, the dual combustion technology employed in this application, where the main combustion zone 11 and the auxiliary combustion zone 12 work in tandem, can increase the local combustion temperature and optimize the combustion atmosphere, significantly reducing the generation of nitrogen oxides (NOx). Additionally, the auxiliary combustion zone 12 aids in the complete combustion of pulverized coal through a high-temperature reaction, reducing particulate matter and sulfur dioxide (SOx) emissions. Furthermore, the exhaust gas generated after combustion enters the emission treatment system 2 (denitrification and desulfurization device) through flue 13 for treatment, removing harmful substances such as NOx and SOx from the exhaust gas to meet environmental emission standards.

[0065] The dual combustion technology of this invention significantly improves the efficiency of coal-fired power generation, reduces the amount of coal used, and greatly reduces the emissions of nitrogen oxides and sulfur dioxide by optimizing the combustion process.

[0066] In addition, the emission control technology of the present invention can effectively cooperate with existing denitrification and desulfurization devices to ensure that coal-fired power generating units can operate efficiently while meeting environmental emission standards and adapting to increasingly stringent environmental requirements.

[0067] In summary, dual combustion systems have the following distinct advantages, including: Improving combustion efficiency: By adding auxiliary fuel (such as liquid fuel or natural gas) to the main combustion zone 11 of pulverized coal, dual combustion can promote the complete combustion of pulverized coal at a higher temperature, thereby significantly improving combustion efficiency. This synergistic combustion not only reduces the residual carbon content of coal but also improves the boiler's thermal efficiency and reduces fuel consumption.

[0068] Reduced harmful gas emissions: Dual combustion optimizes the temperature and atmosphere conditions of the main combustion zone 11 and the auxiliary combustion zone 12, reducing the generation of harmful gases such as nitrogen oxides (NOx) and sulfur dioxide (SO2) during combustion. In addition, auxiliary fuels typically have a higher calorific value, providing a more stable flame temperature during combustion, reducing the possibility of incomplete combustion, and thus reducing emissions of carbon black and other particulate matter.

[0069] Highly adaptable and environmentally friendly: Dual combustion technology allows for flexible adjustment of the ratio between primary and auxiliary combustion, resulting in a more efficient and stable combustion process. This not only adapts to the needs of different fuel types but also effectively addresses the adverse effects of coal quality fluctuations. Furthermore, dual combustion, combined with existing denitrification and desulfurization technologies, can meet more stringent environmental emission standards.

[0070] It is understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of this disclosure, and this disclosure is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and substance of this disclosure, and these modifications and improvements are also considered to be within the scope of protection of this disclosure.

Claims

1. A high-efficiency, low-emission coal-fired power generation system based on dual combustion, characterized in that, include: A dual-combustion boiler is provided with a main combustion zone for burning pulverized coal and an auxiliary combustion zone located upstream of the main combustion zone for burning auxiliary fuel; A combustion control system is used to monitor the combustion conditions of the main combustion zone and the auxiliary combustion zone, and to adjust the auxiliary fuel supply. An emission treatment system is installed in the flue of the dual-combustion boiler to purify the flue gas generated by the dual-combustion boiler.

2. The high-efficiency, low-emission coal-fired power generation system based on dual combustion according to claim 1, characterized in that, Also includes: Heat exchange components and economizers are installed in the flue of the dual-combustion boiler.

3. The high-efficiency, low-emission coal-fired power generation system based on dual combustion according to claim 2, characterized in that, The heat exchange assembly includes a screen-type superheater, a high-temperature superheater, a high-temperature reheater, a first low-temperature reheater, and a low-temperature superheater, which are arranged sequentially along the flue gas flow direction within the flue of the dual-combustion boiler.

4. The high-efficiency, low-emission coal-fired power generation system based on dual combustion according to claim 3, characterized in that, Also includes: A second low-temperature reheater is installed in the flue of the dual-combustion boiler, wherein the second low-temperature reheater is configured to heat the boiler feedwater and transport the heated boiler feedwater to the feedwater inlet of the dual-combustion boiler through a feedwater pipeline.

5. A high-efficiency, low-emission coal-fired power generation system based on dual combustion according to claim 1, characterized in that, The emission treatment system includes a selective catalytic reduction device, which is configured to denitrify or desulfurize the flue gas generated by the dual-combustion boiler.

6. The high-efficiency, low-emission coal-fired power generation system based on dual combustion according to claim 1, characterized in that, Also includes: The air preheater is located at the flue outlet of the dual-combustion boiler and downstream of the emission treatment system. The hot primary air outlet of the air preheater is connected to the pulverized coal tank connected to the main combustion zone via a primary air duct, and the hot secondary air outlet of the air preheater is connected to the main combustion zone via a secondary air duct.

7. The high-efficiency, low-emission coal-fired power generation system based on dual combustion according to claim 1, characterized in that, Also includes: A fuel tank connected to the auxiliary combustion zone via a pipeline and used to store auxiliary fuel, and an auxiliary burner disposed in the auxiliary combustion zone for mixing and burning the auxiliary fuel with air.

8. A high-efficiency, low-emission coal-fired power generation system based on dual combustion according to claim 1, characterized in that, The combustion control system is configured to adjust the combustion ratio of auxiliary fuel to pulverized coal according to the unit load.

9. A high-efficiency, low-emission coal-fired power generation method based on dual combustion, the method being implemented according to the system described in claim 2, characterized in that, include: In the dual-combustion boiler, pulverized coal is burned in the main combustion zone, while auxiliary fuel is burned in the auxiliary combustion zone. The combustion conditions of the main combustion zone and the auxiliary combustion zone are monitored in real time, and the auxiliary fuel supply is adjusted accordingly. The flue gas generated from combustion in the main combustion zone and the auxiliary combustion zone is purified.

10. A method for high-efficiency, low-emission coal-fired power generation based on dual combustion according to claim 9, characterized in that, Also includes: The high-temperature flue gas generated by combustion undergoes heat exchange through the heat exchange components and the economizer.

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