Multi-fuel adaptive front and back wall opposed firing boiler rotational flow combustion system and control method thereof

Abstract

The invention relates to the technical field of heat energy engineering and clean combustion, in particular to a multi-fuel adaptive front and back wall opposed firing boiler rotational flow combustion system and a control method thereof. The system comprises a combustion module, an air supplement module and a control module, the combustion module comprises an inner-layer sleeve and an outer-layer sleeve which are coaxially arranged, the inner-layer sleeve is used for conveying ammonia gas or gasified ash slurry, and the outer-layer sleeve is used for conveying pulverized coal and primary air; the air supplementing module comprises symmetrically distributed air supplementing nozzles and is used for supplementing air to the bottom of the hearth so as to assist fuel combustion through the supplemented air; and the control module is used for adjusting combustion control parameters in the current combustion process based on the real-time combustion monitoring data and a preset neural network model, so that the multi-fuel adaptive front-back wall opposed firing boiler rotational flow combustion system reaches the preset optimal combustion condition. Therefore, the problems of poor fuel adaptability, low combustion efficiency, insufficient environmental protection performance and the like in the prior art are solved, and the stability and flexibility of the combustion process are enhanced.

Description

Technical Field

[0001] This application relates to the fields of thermal energy engineering and clean combustion technology, and in particular to a multi-fuel adaptable front and rear wall opposed-flow boiler swirl combustion system and its control method. Background Technology

[0002] With increasing global focus on environmental protection and sustainable development, reducing greenhouse gas and pollutant emissions has become a key task in the energy sector. Among various energy utilization methods, boiler combustion technology has attracted significant attention due to its widespread application and substantial carbon emissions. Traditional boiler combustion systems face numerous challenges in improving combustion efficiency and reducing pollutant emissions, particularly in multi-fuel co-combustion and low-carbon retrofitting. Therefore, developing a highly efficient, environmentally friendly, and flexible combustion system is of great importance for achieving sustainable energy use.

[0003] In related technologies, the combustion system of front and rear wall opposed boilers mainly adopts a single pulverized coal combustion mode, improving combustion efficiency and reducing pollutant emissions by optimizing burner design and combustion process control. However, although existing front and rear wall opposed boiler combustion systems have improved combustion efficiency and reduced pollutant emissions to some extent, they still suffer from problems such as poor fuel adaptability, low combustion efficiency, and insufficient environmental performance, which urgently need to be addressed. Summary of the Invention

[0004] This application provides a multi-fuel adaptable front and rear wall opposed-flow boiler swirl combustion system to solve the problems of poor fuel adaptability, low combustion efficiency and insufficient environmental performance in the prior art, and enhance the stability and flexibility of the combustion process.

[0005] To achieve the above objectives, the first aspect of this application proposes a multi-fuel-adaptive front and rear wall opposed-flow boiler swirl combustion system, comprising:

[0006] The combustion module includes an inner sleeve and an outer sleeve arranged coaxially. The inner sleeve is used to transport ammonia or gasified ash slurry, and the outer sleeve is used to transport pulverized coal and primary air.

[0007] The make-up air module includes symmetrically distributed make-up air nozzles for supplementing air to the bottom of the furnace to assist fuel combustion.

[0008] The control module is used to adjust the combustion control parameters of the current combustion process based on real-time combustion monitoring data and a preset neural network model, so that the multi-fuel adapted front and rear wall opposed-wall swirl combustion system of the boiler reaches the preset optimal combustion conditions.

[0009] According to one embodiment of this application, the inner sleeve includes an ammonia gas delivery pipe and a porous ammonia gas nozzle, wherein,

[0010] The ammonia gas delivery pipeline is equipped with an ammonia gas valve, which is used to control the ammonia gas flow rate.

[0011] The porous ammonia nozzle is adjacent to the ammonia valve and is located at the end of the inner sleeve. The porous ammonia nozzle includes a base, a flow guide, and a nozzle array, wherein the nozzle array is arranged in concentric circles, and the diameter of each hole is 2-15mm.

[0012] According to one embodiment of this application, the outer sleeve includes:

[0013] A pulverized coal conveying pipeline, the pulverized coal conveying pipeline being used to convey pulverized coal to the outer sleeve;

[0014] A primary air deflector, which is used to determine the flow path of the primary air;

[0015] A primary air nozzle is provided for delivering primary air to the outer sleeve based on the flow path of the primary air to provide the oxygen required for the current combustion process.

[0016] According to one embodiment of this application, a spiral guide rib is provided inside the pulverized coal conveying pipeline. The spiral guide rib is used to achieve a preset mixing requirement by mixing the pulverized coal and the primary air in a turbulent state.

[0017] According to one embodiment of this application, the combustion module further includes: an adjustable swirl blade assembly and a secondary air duct located at the outlet end of the outer sleeve, wherein...

[0018] The secondary air duct includes a secondary air guide plate, which is used to determine the flow path of the secondary air.

[0019] The adjustable swirl blade assembly is used to achieve the preset mixing requirements by adjusting the turbulent mixing state of the pulverized coal and the secondary air based on the flow path of the secondary air.

[0020] According to one embodiment of this application, the aforementioned multi-fuel adapted front and rear wall opposed-wall swirl combustion system for boilers further includes: a coal slurry conveying pipeline and an ash slurry conveying pipeline, wherein...

[0021] The coal slurry conveying pipeline is equipped with a coal slurry pump, which is used to convey coal slurry to the inner sleeve.

[0022] The mortar delivery pipeline is equipped with a mortar pump, which is used to deliver the mortar to the inner sleeve.

[0023] According to one embodiment of this application, the above-mentioned multi-fuel adapted front and rear wall opposed boiler swirl combustion system further includes:

[0024] The wall-mounted air nozzle is located on the side wall of the furnace and is used to spray air towards the side wall of the furnace at a preset speed to form an air film parallel to the side wall of the furnace.

[0025] A burnout air nozzle, which is used to provide oxygen for the current combustion process.

[0026] According to one embodiment of this application, the combustion control parameters include at least one of fuel ratio, swirl intensity, and make-up air volume.

[0027] The multi-fuel adaptable swirl combustion system for a front and rear wall-opposed boiler, as proposed in this application, adjusts the combustion control parameters of the current combustion process based on real-time combustion monitoring data and a preset neural network model through a control module. This enables the multi-fuel adaptable swirl combustion system to achieve preset optimal combustion conditions. Therefore, it solves the problems of poor fuel adaptability, low combustion efficiency, and insufficient environmental performance in existing technologies, and enhances the stability and flexibility of the combustion process.

[0028] To achieve the above objectives, a second aspect of this application provides a control method for a multi-fuel adapted front and rear wall opposed-wall swirl combustion system in a boiler. This method is applied to the multi-fuel adapted front and rear wall opposed-wall swirl combustion system described in the first aspect embodiment, wherein the method includes the following steps:

[0029] Acquire real-time combustion monitoring data of the swirl combustion system of a front and rear wall opposed boiler with multi-fuel compatibility;

[0030] Based on the real-time combustion monitoring data, the combustion state of the multi-fuel adapted front and rear wall opposed boiler swirl combustion system in a preset future period is predicted using a preset neural network model to obtain the prediction result. The preset neural network model is trained from the historical combustion monitoring dataset of the multi-fuel adapted front and rear wall opposed boiler swirl combustion system.

[0031] Based on the prediction results and the real-time combustion monitoring data, the combustion control parameters of the current combustion process are adjusted using a preset multi-objective optimization algorithm, so that the multi-fuel adapted front and rear wall opposed-flow boiler swirl combustion system reaches the preset optimal combustion conditions.

[0032] According to one embodiment of this application, the control method for the multi-fuel adapted front and rear wall opposed-flow boiler swirl combustion system further includes:

[0033] Based on the real-time combustion monitoring data, determine whether there is a need to switch fuel types;

[0034] If there is a need to switch fuel types, obtain the current fuel type, the fuel type to be switched to, and the current operating conditions.

[0035] Based on the current fuel type, the fuel type to be switched, and the current operating conditions, the opening degree of the ammonia valve and / or the pressure of the coal slurry pump and / or the ash slurry pump are adjusted using a preset fuzzy PID (Proportional Integral Derivative) algorithm.

[0036] The control method for a multi-fuel adaptable front and rear wall opposed boiler swirl combustion system proposed in the embodiments of this application solves the problems of poor fuel adaptability, low combustion efficiency, and insufficient environmental performance in the prior art, and enhances the stability and flexibility of the combustion process.

[0037] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through practice of the present application. Attached Figure Description

[0038] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0039] Figure 1 This is a block diagram of a multi-fuel-adaptive front and rear wall opposed-flow boiler swirl combustion system according to an embodiment of this application;

[0040] Figure 2 This is a schematic diagram of the structure of a combustion module according to an embodiment of this application;

[0041] Figure 3 This is a schematic diagram of a porous ammonia nozzle of a combustion module according to an embodiment of this application;

[0042] Figure 4 This is a schematic diagram showing the distribution of wall-mounted air nozzles and make-up air nozzles on the furnace wall according to an embodiment of this application;

[0043] Figure 5 This is a flowchart of a control method for a multi-fuel-adaptive front and rear wall opposed-flow boiler swirl combustion system according to an embodiment of this application. Detailed Implementation

[0044] The embodiments of this application are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0045] The following description, with reference to the accompanying drawings, describes a multi-fuel-adaptive front and rear wall opposed-flow boiler swirl combustion system and its control method according to embodiments of this application.

[0046] Figure 1 This is a block diagram of a multi-fuel adapted front and rear wall opposed boiler swirl combustion system according to an embodiment of this application.

[0047] Before introducing the multi-fuel adaptable front and rear wall opposed boiler swirl combustion system proposed in the embodiments of this application, let’s briefly introduce the relevant technical background.

[0048] In related technologies, front and rear wall opposed-wall boilers generally adopt a single pulverized coal combustion mode. Their technical bottlenecks mainly lie in: poor fuel adaptability; existing swirl burners have a simple structure and cannot be compatible with low-carbon fuels such as ammonia and biomass; for high-moisture fuels, such as lignite, slagging inside the burner is easily caused during combustion; and the gasified ash slurry requires dehydration pretreatment before use, which adds 15%-30% to energy consumption. Secondly, there are also defects in combustion efficiency; the combustion efficiency is low, and for low-calorific-value fuels, such as ash slurry, the burnout rate is often less than 90%; the make-up air measures at the bottom of the furnace are also insufficient, resulting in unburned carbon particles accounting for as high as 5% or even more. In terms of environmental performance, NOx (nitrogen oxides) emissions from pulverized coal combustion typically exceed 100 mg / Nm³. 3 However, when ammonia is co-fired, uneven mixing can lead to ammonia escape. Furthermore, conventional wall-mounted airflow designs may exacerbate sulfide corrosion on the sidewalls. Finally, regarding control strategies, existing DCS (Distributed Control System) systems rely on static parameter settings, which prevents the system from flexibly responding to fluctuations in fuel calorific value, thus affecting overall operating efficiency and stability.

[0049] Based on the aforementioned problems, this application proposes a multi-fuel adaptable swirl combustion system for a front and rear wall opposed-flow boiler. The system includes a combustion module with an inner sleeve that supplies ammonia or gasified ash slurry, and a multi-hole diffuser nozzle at the end of the inner sleeve. An outer sleeve introduces pulverized coal and primary air, and an adjustable swirl blade assembly is configured at its outlet. A makeup air nozzle is arranged at the bottom of the furnace to improve the burnout rate of unburned carbon particles. Combined with an intelligent control module, the combustion control parameters are optimized and adjusted in real time using a neural network model, ensuring optimal combustion conditions. This solves the problems of poor fuel adaptability, low combustion efficiency, and insufficient environmental performance in existing technologies, enhancing the stability and flexibility of the combustion process.

[0050] For example, such as Figure 1As shown, the multi-fuel adaptable front and rear wall opposed-wall swirl combustion system 10 includes a combustion module 100, a makeup air module 200, and a control module 300. The combustion module 100 includes an inner sleeve 101 and an outer sleeve 102 arranged coaxially. The inner sleeve 101 is used to transport ammonia or gasified ash slurry, and the outer sleeve 102 is used to transport pulverized coal and primary air. The makeup air module 200 includes symmetrically distributed makeup air nozzles 201 for supplying air to the bottom of the furnace to assist fuel combustion. The control module 300 is used to adjust the combustion control parameters of the current combustion process based on real-time combustion monitoring data and a preset neural network model, so that the multi-fuel adaptable front and rear wall opposed-wall swirl combustion system achieves the preset optimal combustion conditions.

[0051] Specifically, the combustion module 100 is a nested swirl burner, consisting of an inner sleeve 101 and an outer sleeve 102 arranged coaxially. The main function of the inner sleeve 101 is to transport ammonia or gasified ash slurry, while the outer sleeve 102 is responsible for transporting pulverized coal and primary air, which are the main fuels and oxidants in the combustion process. The inner sleeve 101 is made of Inconel 625 nickel-based alloy, with a silicon nitride coating on its inner wall, ≥0.2mm thick, and an inner diameter of 150-300mm. This material and coating combination can withstand high temperatures (≥1200℃) and prevent corrosion, extending the burner's service life. The outer sleeve 102 can be made of Q345B carbon steel, with a 5mm thick ceramic (Al2O3, alumina, ≥95%) lining embedded in its inner wall, fixed with a high-temperature adhesive, thus forming an annular channel with a width between 50-80mm. By optimizing fuel delivery and mixing, the double-sleeve design significantly improves combustion efficiency and reduces emissions of unburned carbon particles.

[0052] The make-up air module 200, serving as the bottom make-up air system of the furnace, includes symmetrically arranged make-up air nozzles 201. The nozzle body can be made of heat-resistant steel, with the inner wall coated with a SiC (silicon carbide) wear-resistant coating. The nozzle diameter is 80–120 mm, and the nozzle axis forms an angle with the horizontal plane, ranging from 10° to 15°. During installation, the make-up air nozzles 201 can be connected to the high-pressure air duct via flanges. Flange connection is a common pipe connection method, connecting two pipes or devices using flanges and bolts. After installation, an airtightness test is required to verify the nozzle installation quality and ensure that leaks will not affect the normal operation of the system during actual operation. Furthermore, the make-up air nozzles 201 can provide an airflow with a velocity of 40–60 m / s and a temperature maintained within the range of 150–250°C, accounting for 2%–15% of the total air volume. This air supply is used to supply air to the bottom of the furnace, assisting fuel combustion and ensuring a more efficient and complete combustion process. The make-up air nozzle 201 is usually located at the bottom of the furnace, at a certain height (e.g., 1.5-2.5m) from the burner outlet, with a nozzle diameter of 80-120mm. This ensures that air can enter the furnace at an appropriate wind speed and temperature, thereby improving fuel combustion efficiency and reducing pollutant emissions.

[0053] The control module 300 can monitor combustion data in real time (such as furnace temperature, oxygen content, nitrogen oxide concentration, fly ash carbon content, fuel flow rate and pressure, etc.) and use a preset neural network model (such as LSTM (Long Short-Term Memory) neural network model) to dynamically adjust the combustion control parameters of the current combustion process, so as to ensure that the system can reach the preset optimal combustion conditions, thereby optimizing combustion efficiency and reducing emissions.

[0054] Optionally, in some embodiments, the combustion control parameters include at least one of fuel ratio, swirl intensity, and make-up air volume.

[0055] It is understood that combustion control parameters refer to a series of adjustable variables used to regulate and optimize combustion effects during the combustion process. Adjusting these parameters can effectively improve combustion efficiency, reduce pollutant emissions, and ensure the stable operation of the combustion system. Combustion control parameters include fuel ratio, swirl intensity, and make-up air volume. The fuel ratio refers to the proportional relationship between fuel and oxidizer (such as air or oxygen) during combustion. By adjusting the fuel ratio, a theoretically complete combustion state (i.e., stoichiometric combustion) can be achieved, thereby improving energy utilization efficiency and reducing the emission of unburned substances. In this embodiment, the dynamic adjustment range of the ammonia blending ratio is set between 10% and 30%, meaning that the amount of ammonia used can be flexibly adjusted according to actual needs during blending operations. Furthermore, to ensure the safety and efficiency of the blending process, the furnace temperature threshold can be maintained within the range of ≥800℃. Such temperature conditions help ensure the stable operation of the combustion process while avoiding incomplete combustion or equipment damage caused by excessively low temperatures. Swirl intensity refers to the degree of airflow rotation in the burner. Swirl intensity affects the degree of fuel-air mixing within the combustion chamber and the stability of the flame. Appropriate swirl intensity can enhance turbulent mixing, improve combustion efficiency, and reduce localized high-temperature zones, thus lowering nitrogen oxide formation. Makeup air volume refers to the amount of additional air introduced during combustion to supplement the oxygen supply to the main combustion zone. By adjusting the makeup air volume, sufficient oxygen can be ensured for the fuel during combustion, preventing incomplete combustion (such as the formation of carbon monoxide) caused by insufficient oxygen. Furthermore, makeup air can help control combustion temperature distribution and reduce pollutant formation.

[0056] Optionally, in some embodiments, the inner sleeve 101 includes an ammonia delivery pipe 1011 and a porous ammonia nozzle 1012. The ammonia delivery pipe 1011 is provided with an ammonia valve for controlling the ammonia flow rate. The porous ammonia nozzle 1012 is adjacent to the ammonia valve and is located at the end of the inner sleeve 101. The porous ammonia nozzle 1012 includes a base, a flow guide, and a nozzle array. The nozzle array is concentrically distributed, and the diameter of each nozzle is 2-15 mm.

[0057] Specifically, if Figure 2 As shown, the inner sleeve 101 is equipped with an ammonia gas delivery pipe 1011 and a perforated ammonia gas nozzle 1012. The ammonia gas delivery pipe 1011 is equipped with an ammonia gas valve, which precisely controls the flow rate of ammonia gas delivered through the pipe. Furthermore, the perforated ammonia gas nozzle 1012 is located at the end of the inner sleeve 101 and adjacent to the ammonia gas valve to ensure that the ammonia gas can be smoothly and evenly sprayed out. Figure 3As shown, the porous ammonia nozzle 1012 consists of a base, a flow guide, and a nozzle array. The base and flow guide are welded using a vacuum electron beam. To ensure welding quality, the weld seam undergoes rigorous X-ray flaw detection to ensure there are no internal defects. The nozzle array is arranged in a concentric circle pattern (ring array), including 3-4 concentric circles of nozzles. The nozzles are manufactured using electrical discharge machining (EDM) technology. During nozzle manufacturing, the diameter of each nozzle is strictly controlled to ensure its tolerance is within ±0.05mm. Furthermore, the included angle between adjacent nozzle axes is 15°-30°, and the nozzle flow rate consistency error is ≤5%. This design allows for uniform ammonia distribution throughout the injection area. The diameter of each nozzle is between 2-15mm. This size ensures efficient ammonia injection (jet velocity of 60-80m / s) while avoiding uneven ammonia injection that might result from excessively large orifices.

[0058] Optionally, in some embodiments, the outer sleeve 102 includes: a pulverized coal conveying pipe 1021, a primary air guide plate 1022, and a primary air nozzle 1023, wherein the pulverized coal conveying pipe 1021 is used to convey pulverized coal to the outer sleeve 102; the primary air guide plate 1022 is used to determine the flow path of the primary air; and the primary air nozzle 1023 is used to convey primary air to the outer sleeve 102 based on the flow path of the primary air to provide oxygen required for the current combustion process.

[0059] Specifically, if Figure 2 As shown, the outer sleeve 102 comprises three main parts: a pulverized coal conveying pipe 1021, a primary air guide plate 1022, and a primary air nozzle 1023. The main function of the pulverized coal conveying pipe 1021 is to transport pulverized coal to the outer sleeve 102, ensuring smooth combustion. The primary air guide plate 1022 primarily optimizes the flow path of the primary air, ensuring that air is evenly distributed throughout the burner. By setting the primary air guide plate 1022, primary air can enter the burner more evenly, reducing localized excessively high or low air velocities, thereby improving combustion efficiency. The primary air nozzle 1023 is responsible for delivering primary air to the outer sleeve 102. Primary air refers to the airflow first introduced into the furnace during combustion; its main function is to provide the oxygen required for combustion and help the fuel (such as pulverized coal) mix with air to form a combustible mixture, contributing to maintaining combustion stability and efficiency. The primary air velocity ranges from 20 to 26 m / s, while the coal dust concentration can be maintained at 0.4 to 0.6 kg of coal dust per kilogram of air.

[0060] Optionally, in some embodiments, a spiral guide rib is provided inside the pulverized coal conveying pipe 1021. The spiral guide rib is used to achieve a preset mixing requirement by mixing the pulverized coal and the primary air in a turbulent state.

[0061] Specifically, in this embodiment, spiral-shaped guide ribs are added inside the pulverized coal conveying pipe 1021 of the outer sleeve 102. These spiral guide ribs enhance the turbulent mixing effect of the pulverized coal and primary air, effectively forming a stable central recirculation zone, thereby stabilizing the flame. These ribs are set with a 10° tilt angle to ensure smooth pulverized coal flow while avoiding unnecessary resistance to the flow.

[0062] Optionally, in some embodiments, the combustion module 100 further includes: an adjustable swirl blade assembly 103 and a secondary air channel 104 located at the outlet end of the outer sleeve 102, wherein the secondary air channel 104 includes a secondary air guide plate 1041, which is used to determine the flow path of the secondary air; the adjustable swirl blade assembly 103 is used to achieve a preset mixing requirement for the turbulent mixing state of pulverized coal and secondary air based on the flow path of the secondary air.

[0063] Specifically, if Figure 2As shown, the outlet end of the outer sleeve 102 is equipped with an adjustable swirl blade assembly 103. This assembly enhances the turbulent mixing effect of pulverized coal and secondary air, effectively forming a stable central recirculation zone, thereby stabilizing the flame. Secondary air refers to the additional airflow introduced during combustion to supplement oxygen and promote complete fuel combustion. The secondary air channel 104 is the pipe or channel for transporting this air. The adjustable swirl blade assembly 103 can include 6-8 blades, designed to ensure sufficient surface area to influence the fluid. The blades are made of 310S stainless steel (an austenitic stainless steel containing a high proportion of chromium and nickel, possessing excellent high-temperature resistance and corrosion resistance). The adjustable angle of each blade ranges from 45° to 60°, meaning the angle can be dynamically adjusted based on real-time combustion data (such as furnace temperature and oxygen content) to adapt to different operating conditions and requirements. Furthermore, the axial length of the blades (i.e., the length along the rotation axis) is between 200-400 mm. This length range allows the adjustable swirl blade assembly 103 to be flexibly applied in different equipment sizes and fluid channels while maintaining its performance stability and reliability. The blade surfaces are also polished to reduce friction and improve airflow efficiency. These blades are hinged to the outer wall of the sleeve via the rotation axis, enabling flexible angle adjustment. The adjustment range can be set between 45° and 60° to adapt to different operating requirements. In addition, to ensure the precise operating performance of the blade assembly, the accuracy of angle positioning is strictly controlled, ensuring a positioning accuracy of ±0.5°. The main function of the secondary air duct 104 is to deliver secondary air to the outer sleeve 102 of the burner. The main role of the secondary air is to provide additional oxygen, optimize the combustion process, and reduce pollutant emissions. The secondary air duct 104 is equipped with a secondary air guide plate 1041 to determine the flow path of the secondary air, ensuring that the secondary air is evenly distributed to all parts of the burner. By setting the secondary air guide plate 1041, the secondary air can enter the burner more evenly, reducing the situation of excessively high or low local air velocity, thereby improving combustion efficiency.

[0064] Therefore, through the coordinated operation of the secondary air duct 104 and the adjustable swirl blade assembly 103, the flow path and swirl intensity of the secondary air can be optimized, thereby significantly improving the combustion efficiency of the combustion module 100, reducing pollutant emissions, enhancing the system's flexibility and durability, and meeting the combustion requirements under different operating conditions.

[0065] Optionally, in some embodiments, the multi-fuel-adaptive front and rear wall opposed-wall swirl combustion system 10 further includes: a coal slurry conveying pipeline and an ash slurry conveying pipeline, wherein the coal slurry conveying pipeline is equipped with a coal slurry pump for conveying coal slurry to the inner sleeve 101; and the ash slurry conveying pipeline is equipped with an ash slurry pump for conveying ash slurry to the inner sleeve 101.

[0066] Coal slurry is a mixture of coal and water that has undergone pulping treatment, and it has high viscosity and high solids content. Ash slurry is a liquid fuel that has undergone gasification treatment, and it typically contains high ash content and low calorific value.

[0067] Understandably, to achieve multiple fuel modes, this embodiment also includes a coal slurry conveying pipeline and an ash slurry conveying pipeline. The coal slurry conveying pipeline can be made of wear-resistant materials (such as carbon steel or alloy steel) to cope with the wear of the coal slurry, and can be designed as a ring or spiral to ensure that the coal slurry can enter the combustion module 100 evenly, avoiding sedimentation or blockage during the conveying process. Furthermore, a coal slurry pump is installed on the coal slurry conveying pipeline to provide sufficient pressure to convey the coal slurry to the inner sleeve 101. The ash slurry conveying pipeline can be made of high-temperature and corrosion-resistant materials (such as stainless steel or alloy steel) to cope with the corrosiveness of the ash slurry, and can also be designed as a ring or spiral to ensure that the ash slurry can enter the combustion module 100 evenly, avoiding sedimentation or blockage during the conveying process. Similarly, an ash slurry pump can also be installed on the ash slurry conveying pipeline to provide sufficient pressure to convey the ash slurry to the inner sleeve 101. Through the porous ammonia nozzle 1012 at the end of the inner sleeve 101, fuel (such as pulverized coal, coal slurry, ash slurry, etc.) can be evenly injected into the furnace to ensure sufficient diffusion and mixing of the fuel.

[0068] Therefore, by setting up coal slurry conveying pipelines and ash slurry conveying pipelines, the multi-fuel adaptable front and rear wall counter-flow boiler swirl combustion system 10 can flexibly switch fuel types to adapt to different combustion needs. For example, when it is necessary to reduce NOx emissions, it can be switched to ammonia co-firing mode; when it is necessary to improve combustion efficiency, it can be switched to coal slurry or ash slurry mode.

[0069] Optionally, in some embodiments, the multi-fuel-adaptive front and rear wall opposed swirl combustion system 10 of the boiler further includes: a wall-mounted air nozzle 400 and a burnout air nozzle 500, wherein the wall-mounted air nozzle 400 is located on the furnace side wall and is used to spray air at a preset speed toward the furnace side wall to form an air film parallel to the furnace side wall; the burnout air nozzle 500 is used to provide oxygen for the current combustion process.

[0070] It is understandable that, such as Figure 4As shown, to achieve a synergistic effect of low nitrogen emissions and corrosion prevention, this embodiment employs a staggered arrangement of wall-mounted air nozzles 400 and burnout air nozzles 500. Specifically, flattened wall-mounted air nozzles 400 are arranged on the furnace sidewalls. These nozzles generate high-speed airflow (carrying air) of 40-80 m / s, with an airflow volume ratio between 2% and 15%. The wall-mounted air nozzles 400 effectively isolate reducing gases such as H2S and CO by forming a stable gas film between the parallel sidewalls, preventing high-temperature corrosion of the water-cooled walls. This gas film provides protection, reducing the erosion of equipment and structures by these gases, thereby extending the equipment's service life and reducing maintenance costs.

[0071] To further optimize the combustion process and ensure complete combustion of harmful substances in the flue gas, the burnout air nozzle 500 can dynamically adjust according to current load changes. This adjustment allows the nozzle to deflect between 20° and 35°, effectively creating a dual-circulation flow pattern. This pattern helps extend the residence time of flue gas in the combustion chamber. This design not only optimizes combustion efficiency but also reduces the emission of harmful substances (such as NOx) (promoting NOx reduction) and improves overall combustion performance. Through this synergistic design, the system's corrosion resistance is enhanced, and low NOx emissions are ensured, achieving the dual goals of environmental protection and economic benefits.

[0072] The multi-fuel adaptable swirl combustion system for a front and rear wall-opposed boiler, as proposed in this application, adjusts the combustion control parameters of the current combustion process based on real-time combustion monitoring data and a preset neural network model through a control module. This enables the multi-fuel adaptable swirl combustion system to achieve preset optimal combustion conditions. Therefore, it solves the problems of poor fuel adaptability, low combustion efficiency, and insufficient environmental performance in existing technologies, and enhances the stability and flexibility of the combustion process.

[0073] Next, with reference to the accompanying drawings, a control method for a multi-fuel-adaptive front and rear wall opposed-flow boiler swirl combustion system according to an embodiment of this application is described.

[0074] Figure 5 This is a flowchart of a control method for a multi-fuel adapted front and rear wall opposed boiler swirl combustion system according to an embodiment of this application.

[0075] like Figure 5 As shown, the control method of this multi-fuel adapted front and rear wall opposed-wall swirl combustion system is applied to... Figure 1 The multi-fuel-adaptive front and rear wall opposed-flow boiler swirl combustion system of the embodiment, wherein the method includes the following steps:

[0076] In step S501, real-time combustion monitoring data of the front and rear wall opposed-flow boiler swirl combustion system with multi-fuel adaptation is obtained.

[0077] Specifically, by arranging multiple sensors in the combustion system, real-time combustion monitoring data of the swirl combustion system of the front and rear wall opposed boiler with multi-fuel compatibility can be collected, such as furnace temperature, oxygen content (O2%), NOx concentration, fly ash carbon content, fuel flow rate and pressure.

[0078] In step S502, based on real-time combustion monitoring data, a preset neural network model is used to predict the combustion state of the multi-fuel adapted front and rear wall opposed boiler swirl combustion system in a preset future period, and the prediction result is obtained. The preset neural network model is trained from the historical combustion monitoring dataset of the multi-fuel adapted front and rear wall opposed boiler swirl combustion system.

[0079] Specifically, after obtaining real-time combustion monitoring data, the collected data can be cleaned, filtered, and normalized to extract key features, providing input for the neural network model. Then, using a pre-defined neural network model (such as LSTM), the future combustion state, including the changing trends of key parameters such as furnace temperature, oxygen content, and NOx concentration, can be predicted based on the real-time combustion monitoring data.

[0080] It should be noted that the pre-defined neural network model can be trained by analyzing and learning from past combustion monitoring datasets of a multi-fuel-adaptive front and rear wall opposed-wall swirl combustion system. The specific training process involves the following steps: First, collect a large amount of historical combustion monitoring data, covering combustion states under different fuel types and operating conditions to ensure the model's generalization ability. Then, preprocess this data, including data cleaning, missing value imputation, and outlier handling, to improve data quality. Next, based on the problem definition, select an appropriate neural network architecture, such as a Deep Neural Network (DNN), Convolutional Neural Network (CNN), or Recurrent Neural Network (RNN) and its variant LSTM, designing the number of network layers and neurons per layer specifically for the characteristics of the multi-fuel-adaptive front and rear wall opposed-wall swirl combustion system. During the model training phase, the backpropagation algorithm is used to optimize the network parameters, minimizing the error between predicted and actual values. Through multiple iterative training iterations, the model converges, achieving the predetermined accuracy requirements. Finally, the trained model is evaluated to verify its performance on unseen data, ensuring the model's stability and reliability.

[0081] In step S503, based on the prediction results and real-time combustion monitoring data, the combustion control parameters of the current combustion process are adjusted using a preset multi-objective optimization algorithm, so that the multi-fuel-adaptive front and rear wall opposed boiler swirl combustion system reaches the preset optimal combustion conditions.

[0082] Specifically, after obtaining the prediction results, combustion control parameters can be dynamically adjusted based on the prediction results and real-time combustion monitoring data using a preset multi-objective optimization algorithm (such as NSGA-II (Non-dominated Sorting Genetic Algorithm II, an elite-strategy non-dominated sorting genetic algorithm)) to bring the combustion system to the preset optimal combustion conditions. The preset multi-objective optimization algorithm can effectively balance nitrogen oxide (NOx) emissions, fuel burnout rate, and steam parameter stability, thereby achieving multiple optimization objectives and finding the optimal combination of combustion control parameters (i.e., fuel ratio, swirl intensity, and make-up air volume). For the fuel ratio, the proportion of different fuels (such as pulverized coal, ammonia, biomass, etc.) is dynamically adjusted according to the combustion state. By optimizing the fuel ratio, pollutant emissions are reduced and combustion efficiency is improved. For the swirl intensity, the mixing effect of pulverized coal and primary air is optimized by adjusting the angle of the swirl blades. By optimizing the swirl intensity, combustion efficiency is improved and unburned carbon particles are reduced. Regarding the make-up air volume, the combustion process is optimized by adjusting the volume and velocity of the primary air, secondary air, and make-up air. By optimizing the make-up air volume, sufficient oxygen is provided to ensure complete combustion of fuel and reduce pollutant emissions.

[0083] Therefore, this process not only improves combustion efficiency and reduces pollutant emissions, but also enhances the system's flexibility and durability, making it suitable for various fuel modes and meeting combustion requirements under different operating conditions.

[0084] Furthermore, in some embodiments, the control method of the multi-fuel-adaptive front and rear wall counter-flow boiler swirl combustion system described above further includes: determining whether there is a fuel type switching requirement based on real-time combustion monitoring data; if there is a fuel type switching requirement, obtaining the current fuel type, the fuel type to be switched, and the current operating conditions; and adjusting the opening degree of the ammonia valve and / or the pressure of the coal slurry pump and / or the ash slurry pump using a preset fuzzy PID algorithm according to the current fuel type, the fuel type to be switched, and the current operating conditions.

[0085] Specifically, based on real-time monitoring data and preset control strategies, the intelligent control system (control module) analyzes the real-time monitoring data to determine whether there is a need to switch fuel types. For example, when the NOx concentration exceeds a set threshold (e.g., 50 mg / Nm³), the system will determine whether a fuel type switch is required. 3When the fly ash carbon content is too high (e.g., exceeding the fly ash carbon content threshold of 3%), it may be necessary to switch to the ash slurry mode. If the intelligent control system triggers a fuel switching command (i.e., there is a need to switch fuel types), it can further obtain the current fuel type (e.g., pulverized coal, ammonia co-firing, biomass mixing, etc.), the fuel type to be switched (e.g., switching from pulverized coal to ammonia co-firing, or from ammonia co-firing to ash slurry mode), and the current operating conditions (i.e., the current operating status of the combustion system, including key parameters such as furnace temperature, oxygen content, air volume, and wind speed). Based on the current fuel type, the fuel type to be switched, and the current operating conditions, the specific operating steps and parameter adjustment strategies during the switching process can be further determined.

[0086] During fuel type switching, a fuzzy PID algorithm can be used to dynamically adjust the opening of the ammonia valve and / or the pressure of the coal slurry pump and / or ash slurry pump to achieve a smooth transition during the fuel type switching process. The fuzzy PID algorithm (a preset fuzzy PID algorithm) is an intelligent control algorithm that combines fuzzy logic and PID control, capable of dynamically adjusting control parameters based on real-time monitoring data.

[0087] For example, when the initial fuel is pulverized coal, the primary air velocity is set to the design value; after the furnace temperature rises to 800°C, the ammonia valve is gradually opened, with ammonia accounting for 10% of the total calorific value.

[0088] When switching from pulverized coal to ammonia co-firing mode, the intelligent control system can maintain the furnace temperature at or above 800℃; send commands to increase the opening of the ammonia valve; and dynamically adjust the opening of the make-up air nozzle based on the oxygen content (O2%) to maintain the oxygen content within the range of 3%-5%. Notably, when the furnace temperature is below 700℃ or the oxygen content is below 2%, the ammonia supply can be forcibly cut off. Furthermore, when the NOx concentration is detected to exceed the set safety threshold, the intelligent control system can automatically increase the ammonia co-firing ratio.

[0089] When switching from ammonia co-firing to mortar slurry mode, the intelligent control system can shut off the ammonia valve; start the mortar slurry pump and adjust the pump pressure to control the mortar flow rate; simultaneously increase the air velocity at the make-up air nozzles and increase the air volume ratio; monitor the carbon content of fly ash, and if it exceeds the limit, increase the intensity of the secondary air swirl. It is worth noting that when the solid content of the mortar slurry is less than 40%, an alarm can be triggered and the injection of mortar slurry can be suspended.

[0090] When switching to biomass mixing mode, biomass particles (particle size ≤ 3mm) can be mixed with coal powder at a ratio of 1:3; the secondary air swirl intensity can be reduced to 40° to prevent slagging; and the wall-mounted air volume can be increased to 12% of the total air volume to inhibit sidewall corrosion.

[0091] It should be noted that the explanation and description of the aforementioned embodiment of the multi-fuel adapted front and rear wall opposed boiler swirl combustion system also applies to the control method of the multi-fuel adapted front and rear wall opposed boiler swirl combustion system of this embodiment, and will not be repeated here.

[0092] The control method for a multi-fuel adaptable front and rear wall opposed boiler swirl combustion system proposed in the embodiments of this application solves the problems of poor fuel adaptability, low combustion efficiency, and insufficient environmental performance in the prior art, and enhances the stability and flexibility of the combustion process.

[0093] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0094] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0095] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A multi-fuel adaptable front and rear wall opposed-flow boiler swirl combustion system, characterized in that, include: The combustion module includes an inner sleeve and an outer sleeve arranged coaxially. The inner sleeve is used to transport ammonia or gasified ash slurry, and the outer sleeve is used to transport pulverized coal and primary air. The make-up air module includes symmetrically distributed make-up air nozzles for supplementing air to the bottom of the furnace to assist fuel combustion. The control module is used to adjust the combustion control parameters of the current combustion process based on real-time combustion monitoring data and a preset neural network model, so that the multi-fuel adapted front and rear wall opposed-wall swirl combustion system of the boiler reaches the preset optimal combustion conditions.

2. The system according to claim 1, characterized in that, The inner sleeve includes an ammonia gas delivery pipe and a porous ammonia gas nozzle, wherein, The ammonia gas delivery pipeline is equipped with an ammonia gas valve, which is used to control the ammonia gas flow rate. The porous ammonia nozzle is adjacent to the ammonia valve and is located at the end of the inner sleeve. The porous ammonia nozzle includes a base, a flow guide, and a nozzle array, wherein the nozzle array is arranged in concentric circles, and the diameter of each hole is 2-15mm.

3. The system according to claim 2, characterized in that, The outer sleeve includes: A pulverized coal conveying pipeline, the pulverized coal conveying pipeline being used to convey pulverized coal to the outer sleeve; A primary air deflector, which is used to determine the flow path of the primary air; A primary air nozzle is provided for delivering primary air to the outer sleeve based on the flow path of the primary air to provide the oxygen required for the current combustion process.

4. The system according to claim 3, characterized in that, The coal powder conveying pipeline is equipped with spiral guide ribs inside, which are used to achieve a preset mixing state of turbulent mixing between the coal powder and the primary air.

5. The system according to claim 4, characterized in that, The combustion module further includes: an adjustable swirl blade assembly and a secondary air duct located at the outlet end of the outer sleeve, wherein, The secondary air duct includes a secondary air guide plate, which is used to determine the flow path of the secondary air. The adjustable swirl blade assembly is used to achieve the preset mixing requirements by adjusting the turbulent mixing state of the pulverized coal and the secondary air based on the flow path of the secondary air.

6. The system according to claim 1, characterized in that, Also includes: Coal slurry conveying pipelines and ash slurry conveying pipelines, among which, The coal slurry conveying pipeline is equipped with a coal slurry pump, which is used to convey coal slurry to the inner sleeve. The mortar delivery pipeline is equipped with a mortar pump, which is used to deliver the mortar to the inner sleeve.

7. The system according to claim 1, characterized in that, Also includes: The wall-mounted air nozzle is located on the side wall of the furnace and is used to spray air towards the side wall of the furnace at a preset speed to form an air film parallel to the side wall of the furnace. A burnout air nozzle, which is used to provide oxygen for the current combustion process.

8. The system according to claim 1, characterized in that, The combustion control parameters include at least one of fuel ratio, swirl intensity, and make-up air volume.

9. A control method for a multi-fuel adaptable front and rear wall opposed-wall swirl combustion system in a boiler, characterized in that, The method is applied to a multi-fuel adapted front and rear wall opposed-flow boiler swirl combustion system as described in any one of claims 1-8, wherein the method includes the following steps: Acquire real-time combustion monitoring data of the swirl combustion system of a front and rear wall opposed boiler with multi-fuel compatibility; Based on the real-time combustion monitoring data, the combustion state of the multi-fuel adapted front and rear wall opposed boiler swirl combustion system in a preset future period is predicted using a preset neural network model to obtain the prediction result. The preset neural network model is trained from the historical combustion monitoring dataset of the multi-fuel adapted front and rear wall opposed boiler swirl combustion system. Based on the prediction results and the real-time combustion monitoring data, the combustion control parameters of the current combustion process are adjusted using a preset multi-objective optimization algorithm, so that the multi-fuel adapted front and rear wall opposed-flow boiler swirl combustion system reaches the preset optimal combustion conditions.

10. The method according to claim 9, characterized in that, Also includes: Based on the real-time combustion monitoring data, determine whether there is a need to switch fuel types; If there is a need to switch fuel types, obtain the current fuel type, the fuel type to be switched to, and the current operating conditions. Based on the current fuel type, the fuel type to be switched, and the current operating conditions, the opening degree of the ammonia valve and / or the pressure of the coal slurry pump and / or the ash slurry pump are adjusted using a preset fuzzy PID algorithm.

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