Low-load mixed coal blending combustion device and method based on circulating fluidized bed boiler

Abstract

The invention relates to a low-load mixed coal blending combustion device and method based on a circulating fluidized bed boiler, and the device comprises a preheating modification device which is used for gasifying and combusting raw coal under the condition of a preset low air equivalence ratio; the coal slime feeding system is used for conveying the coal slime meeting the preset moisture content to the furnace top of the circulating fluidized bed boiler; the secondary air system is used for controlling the coal slime blocks to rotate and controlling the coal slime blocks to be subjected to suspension combustion so as to form unburned blocks; the separator is used for carrying out gas-solid separation on the unburned blocks and the flue gas; the return feeder is used for returning the separated gas and the separated solid into the circulating fluidized bed boiler; and the mixed coal blending combustion module is used for controlling the coal slime proportion of the circulating fluidized bed boiler according to the energy fluctuation so as to generate a mixed coal blending combustion result meeting a preset low-load condition. The invention provides a novel combustion technology and a novel load control strategy so as to improve the operation performance of the circulating fluidized bed boiler with the high coal slime proportion.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of combustion boilers, and particularly relates to a low-load mixed coal blending device and method based on a circulating fluidized bed boiler. BACKGROUND

[0002] At present, the CFB (Circulating Fluidized Bed) boiler blending technology mainly focuses on blending coal slime, sludge, municipal waste, coal gangue, petroleum coke, biomass and other substances.

[0003] In the related art, a double-cylinder plunger pump with an S-swing can be used to transport coal slime, and a coal slime gun with an atomization function is used to transport coal slime. When the coal slime gun is running, compressed air is used to atomize the coal slime, so as to facilitate the burning of the coal slime, and a wall box sealing air is arranged to avoid the gun head from being burnt out. The water content of the coal slime entering the coal slime conveying system is controlled, and a discharging screw device and a coal slime bin stirring device are arranged in the conveying pipeline of the coal slime conveying system, which are used to uniformly control the water content of the coal slime, so as to improve the discharging screw output.

[0004] However, the related art focuses on the high-load blending of inferior coal, and the research on the low-load blending of inferior coal with a large proportion is less, and the research on the blending proportion is less at present, and the research on the blending of inferior coal with a large proportion is less, which needs to be improved. SUMMARY

[0005] The present application provides a low-load mixed coal blending device and method based on a circulating fluidized bed boiler, so as to solve the problems that the related art focuses on the high-load blending of inferior coal, the research on the low-load blending of inferior coal with a large proportion is less, and the research on the blending proportion is less at present, and the research on the blending of inferior coal with a large proportion is less.

[0006] The first aspect of this application provides a low-load coal blending and combustion device based on a circulating fluidized bed boiler, comprising: a preheating and modification device for gasifying and burning raw coal under a preset low air equivalence ratio condition to generate a gas-solid binary fuel composed of coal gas and char that meets preset high-temperature conditions, and introducing the gas-solid binary fuel into the circulating fluidized bed boiler for combustion reaction to generate combustion reaction parameters; a coal slime feeding system for conveying coal slime with a preset moisture content to the top of the circulating fluidized bed boiler based on the combustion reaction parameters, and allowing the coal slime from the top of the boiler to fall into the furnace of the circulating fluidized bed along a slurry pipe to form coal slime blocks; and a secondary air system for asymmetric secondary air in the furnace. With the flow on both sides of the wall, the coal slime blocks are controlled to rotate and undergo suspension combustion to form unburned blocks; a separator is used to separate the unburned blocks and flue gas into separated gas and separated solids; a return feeder is used to return the separated gas and separated solids to the circulating fluidized bed boiler for a new combustion cycle, generating a combustion cycle result; a coal blending module is used to obtain the energy fluctuation of the coal slime by utilizing the energy storage of the circulating fluidized bed boiler based on the combustion cycle result, and to control the coal slime ratio of the circulating fluidized bed boiler according to the energy fluctuation to generate a coal blending result that meets the preset low load conditions.

[0007] Optionally, in one embodiment of this application, the coal slime feeding system includes: an execution unit for performing at least one of the following actions on the coal slime under a preset furnace temperature condition: drying, agglomeration, volatilization, thermal explosion, combustion, and falling, to form the coal slime block.

[0008] Optionally, in one embodiment of this application, it further includes: a suspension combustion module, used to generate a final suspension combustion result when the unburned block falls onto the surface of the circulating fluidized bed and the unburned block floats above the coal gangue; and an internal circulation fluidized combustion module, used to crush, wear, break, aggregate, rise, sink, disperse, and burn out the unburned block based on the final suspension combustion result, so as to obtain an internal circulation fluidized combustion result.

[0009] Optionally, in one embodiment of this application, it further includes: a bed material conveying system for conveying coal gangue particles that meet preset high-density conditions to the bottom of the fluidized bed.

[0010] Optionally, in one embodiment of this application, the average flow velocity of the coal slime is:

[0011]

[0012] in, The Reynolds number is... The desired flow rate of the circulating fluidized bed boiler. The density of coal slime, and These are rheological property parameters. D This refers to the inner diameter of the pipe. The in-furnace heat transfer equation for the circulating fluidized bed boiler is as follows:

[0013]

[0014]

[0015] in, Fuel consumption The amount of heat transferred per kilogram of combustion products to the furnace heating surfaces and materials. For insulation coefficient, To determine the effective value of heat release, X For valid values share, The enthalpy of ash at the furnace outlet. For the enthalpy of ash at the furnace mouth, For circulating ash quantity, The enthalpy of the flue gas at the furnace outlet. k m The furnace heat transfer coefficient, The furnace heating surface area, The furnace opening temperature, This refers to the tube wall temperature at the water-cooled wall. The excess air coefficient at the furnace outlet. The excess air coefficient at the return valve inlet. , These are the enthalpy of hot air and the enthalpy of cold air, respectively. The in-furnace heat transfer coefficient of the circulating fluidized bed boiler is:

[0016] in, The heat transfer coefficient is... k 0 represents the ratio. A and B All are constant coefficients. The concentration of suspended particles. T This represents the average temperature inside the furnace.

[0017] Optionally, in one embodiment of this application, the in-furnace carbon combustion formula of the circulating fluidized bed boiler is:

[0018] in, For the amount of carbon burned, For fuel feed rate, To receive basic net carbon, The rate of carbon combustion. This refers to the average carbon content of the slag. For slag removal rate, This represents the average carbon content of fly ash. This represents the fly ash input rate.

[0019] Optionally, in one embodiment of this application, the coal blending module includes: a composition unit, used to compose a first feedforward control sub-signal of the coal slime through a differential program and a proportional component; an adjustment unit, used to eliminate the main steam pressure deviation based on the first feedforward control sub-signal and utilize a second control sub-signal of the coal slime to adjust the load demand and obtain the energy fluctuation of the coal slime; a suppression unit, used to suppress the energy fluctuation of the coal slime in the early stage of the energy fluctuation of the coal slime using a third sub-signal of the coal slime to generate a suppression result; and a control unit, used to perform PI feedback supplementary control of the air-coal ratio based on the suppression result and utilize a fourth sub-signal of the coal slime to generate the coal blending result that meets the preset low load conditions.

[0020] The second aspect of this application provides a low-load coal blending method based on a circulating fluidized bed boiler, comprising the following steps: gasifying and burning raw coal under a preset low air equivalence ratio condition to generate a gas-solid binary fuel composed of coal gas and char that meets preset high-temperature conditions; introducing the gas-solid binary fuel into the circulating fluidized bed boiler for combustion reaction to generate combustion reaction parameters; based on the combustion reaction parameters, conveying coal slurry with a preset moisture content to the top of the circulating fluidized bed boiler, and allowing the coal slurry from the top to fall into the furnace of the circulating fluidized bed through a slurry pipe to form coal slurry blocks; and then, with asymmetric secondary air in the furnace... When the flow is on both sides of the wall, the coal slurry blocks are controlled to rotate and undergo suspension combustion to form unburned blocks; the unburned blocks and flue gas are separated into gas and solid to obtain separated gas and separated solid; the separated gas and separated solid are returned to the circulating fluidized bed boiler to carry out a new combustion cycle and generate a combustion cycle result; based on the combustion cycle result, the circulating fluidized bed boiler is used to store energy to obtain the energy fluctuation of the coal slurry, and the coal slurry ratio of the circulating fluidized bed boiler is controlled according to the energy fluctuation to generate a blended coal combustion result that meets the preset low load conditions.

[0021] Optionally, in one embodiment of this application, the step of conveying coal slurry with a preset moisture content to the top of the circulating fluidized bed boiler and dropping the coal slurry from the top of the boiler into the furnace of the circulating fluidized bed through a slurry pipe to form coal slurry blocks includes: performing at least one of the following actions on the coal slurry under a preset furnace temperature condition: drying, agglomeration, volatilization, thermal explosion, combustion, and falling, to form the coal slurry blocks.

[0022] Optionally, in one embodiment of this application, the method further includes: generating a final suspension combustion result when the unburned lumps fall onto the surface of the circulating fluidized bed and float above the coal gangue; based on the final suspension combustion result, the unburned lumps are subjected to crushing, abrasion, fragmentation, aggregation, rising, sinking, blowing, and burnout to obtain an internal circulating fluidized bed combustion result. Optionally, in one embodiment of this application, it further includes: conveying coal gangue particles that meet preset high-density conditions to the bottom of the fluidized bed.

[0023] Optionally, in one embodiment of this application, the average flow velocity of the coal slime is:

[0024]

[0025] in, The Reynolds number is... The desired flow rate of the circulating fluidized bed boiler. The density of coal slime, and These are rheological property parameters. D This refers to the inner diameter of the pipe. The in-furnace heat transfer equation for the circulating fluidized bed boiler is as follows:

[0026]

[0027]

[0028] in, Fuel consumption The amount of heat transferred per kilogram of combustion products to the furnace heating surfaces and materials. For insulation coefficient, To determine the effective value of heat release, X For valid values share, The enthalpy of ash at the furnace outlet. For the enthalpy of ash at the furnace mouth, For circulating ash quantity, The enthalpy of the flue gas at the furnace outlet.k m The furnace heat transfer coefficient, The furnace heating surface area, The furnace opening temperature, This refers to the tube wall temperature at the water-cooled wall. The excess air coefficient at the furnace outlet. The excess air coefficient at the return valve inlet. , These are the enthalpy of hot air and the enthalpy of cold air, respectively. The in-furnace heat transfer coefficient of the circulating fluidized bed boiler is:

[0029] in, The heat transfer coefficient is... k 0 represents the ratio. A and B All are constant coefficients. The concentration of suspended particles. T This represents the average temperature inside the furnace.

[0030] Optionally, in one embodiment of this application, the in-furnace carbon combustion formula of the circulating fluidized bed boiler is:

[0031] in, For the amount of carbon burned, For fuel feed rate, To receive basic net carbon, The rate of carbon combustion. This refers to the average carbon content of the slag. For slag removal rate, This represents the average carbon content of fly ash. This represents the fly ash input rate.

[0032] Optionally, in one embodiment of this application, the low-load coal blending module includes: a first feedforward control sub-signal composed of a differential program and a proportional component; based on the first feedforward control sub-signal, a second control sub-signal of the coal slime is used to eliminate the main steam pressure deviation to adjust the load demand and obtain the energy fluctuation of the coal slime; in the early stage of the energy fluctuation of the coal slime, a third sub-signal of the coal slime is used to suppress the energy fluctuation of the coal slime and generate a suppression result; based on the suppression result, a fourth sub-signal of the coal slime is used to perform PI feedback supplementary control of the air-coal ratio to generate the coal blending result that meets the preset low-load conditions.

[0033] A third aspect of this application provides an electronic device, including: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the low-load coal blending method based on a circulating fluidized bed boiler as described in the above embodiments.

[0034] A fourth aspect of this application provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described low-load coal blending method based on a circulating fluidized bed boiler.

[0035] This application embodiment utilizes a preheating modification device to gasify and burn raw coal under a preset low air equivalence ratio condition. A coal slime feeding system, meeting a preset moisture content, is transported to the top of a circulating fluidized bed boiler. A secondary air system controls the rotation of the coal slime blocks and controls their suspension combustion to form unburned blocks. A separator separates the unburned blocks from the flue gas, yielding separated gas and separated solids. A return feeder returns the separated gas and separated solids to the circulating fluidized bed boiler. A coal blending module controls the coal slime ratio in the circulating fluidized bed boiler based on energy fluctuations to generate a blended coal combustion result that meets preset low load conditions. Addressing the problems of low boiler thermal efficiency, combustion efficiency, and coal slime mixing ratio in circulating fluidized bed boiler combustion technology, a novel combustion technology is proposed. Furthermore, to address the instability in circulating fluidized bed boiler operation caused by energy fluctuations during coal slime combustion, a new load control strategy based on energy storage theory is proposed to improve the operating performance of circulating fluidized bed boilers with high coal slime ratios. This addresses the issues that related technologies focus on high-load blending of inferior coal conditions, with limited research on low-load, high-proportion blending of inferior coal conditions, and that current research primarily focuses on small blending ratios while neglecting high-proportion blending of inferior coal.

[0036] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0037] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein: Figure 1 This is a schematic diagram of a low-load coal blending and co-firing device based on a circulating fluidized bed boiler, according to an embodiment of this application. Figure 2 This is a schematic diagram of a fuel high-temperature preheating modification technology according to an embodiment of this application; Figure 3 This is a schematic diagram of asymmetric secondary wind according to an embodiment of this application; Figure 4 This is a schematic diagram of the control strategy of a coal slime mixing circulating fluidized bed unit according to an embodiment of this application; Figure 5 This is a flowchart illustrating a low-load coal blending method based on a circulating fluidized bed boiler, according to an embodiment of this application. Figure 6 This is a schematic diagram of the structure of an electronic device provided according to an embodiment of this application. Detailed Implementation

[0038] The embodiments of this application are described in detail below. Examples of these 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.

[0039] The following description, with reference to the accompanying drawings, describes a low-load coal blending device and method based on a circulating fluidized bed boiler according to embodiments of this application. Addressing the issues mentioned in the background art, which focuses on high-load blending of inferior coal and has limited research on low-load, high-proportion blending of inferior coal, and the current prevalence of research on small blending ratios with limited research on large-proportion blending of inferior coal, this application provides a low-load coal blending device based on a circulating fluidized bed boiler. This device addresses the problems of low boiler thermal efficiency, combustion efficiency, and coal slurry mixing ratio in circulating fluidized bed boiler combustion technology by proposing a novel combustion technology. Furthermore, to address the energy fluctuations caused by coal slurry combustion leading to unstable operation of the circulating fluidized bed boiler, a new load control strategy based on energy storage theory is proposed to improve the operating performance of circulating fluidized bed boilers with high coal slurry ratios. This solves the problems of related technologies focusing on high-load blending of inferior coal and limited research on low-load, high-proportion blending of inferior coal, and the current prevalence of research on small blending ratios with limited research on large-proportion blending of inferior coal.

[0040] Specifically, Figure 1 This is a schematic diagram of the structure of a low-load coal blending device 10 based on a circulating fluidized bed boiler, provided in an embodiment of this application.

[0041] like Figure 1 As shown, the low-load coal blending and co-firing device 10 based on a circulating fluidized bed boiler includes: Specifically, the preheating and modification device 100 is used to gasify and burn raw coal under a preset low air equivalence ratio condition to generate a gas-solid binary fuel composed of coal gas and char that meets the preset high temperature conditions. The gas-solid binary fuel is then introduced into a circulating fluidized bed boiler for combustion reaction to generate combustion reaction parameters.

[0042] It is understood that the preset low air equivalence ratio condition in the embodiments of this application can be a low air equivalence ratio (0.3-0.4).

[0043] In practical implementation, this application provides a novel combustion technology that involves the partial combustion of raw coal in a preheating and modification device 100 (PMD) with a low air equivalence ratio (0.3-0.4), converting the solid fuel into a gas-solid binary fuel composed of high-temperature coal gas and high-temperature char. Subsequently, the high-temperature gas-solid binary fuel enters a CFB (Circulating Fluidized Bed) to complete a primary combustion reaction. During the fuel preheating and modification process, two key objectives are achieved: pre-removal of fuel nitrogen and activation modification of the fuel. Pre-removal of fuel nitrogen has a positive effect on reducing NOx emissions, and the high-temperature gas and coke generated during the fuel preheating and modification process increase the variable load rate, such as... Figure 2 As shown.

[0044] Circulating fluidized bed (CFB) boilers face challenges in achieving high boiler thermal efficiency, combustion efficiency, and a high coal slurry mixing ratio. To address these issues, a novel combustion technology is proposed. This application demonstrates how this new combustion technology can be applied to CFB boilers, aiming to improve the variable load rate and combustion efficiency of the circulating fluidized bed, as well as reduce its NOx content. x emission.

[0045] It should be noted that the preset low air equivalence ratio condition can be set by those skilled in the art according to the actual situation, and no specific restrictions are imposed here.

[0046] Optionally, in one embodiment of this application, the low-load coal blending device 10 based on a circulating fluidized bed boiler further includes: a bed material conveying system for conveying coal gangue particles that meet preset high-density conditions to the bottom of the fluidized bed.

[0047] It is understood that the coal gangue particles with preset high density conditions in the embodiments of this application can be coal gangue particles with high density and different particle sizes.

[0048] In this embodiment of the application, some high-density coal gangue particles of different sizes are transported to the bottom of the fluidized bed through a bed material conveying system to ensure the bed pressure of the circulating fluidized bed.

[0049] It should be noted that the preset high-density conditions can be set by those skilled in the art according to the actual situation, and no specific restrictions are imposed here.

[0050] The coal slime feeding system 200 is used to transport coal slime with a preset moisture content to the top of the circulating fluidized bed boiler based on parameters of the combustion reaction, and to drop the coal slime from the top of the boiler into the furnace of the circulating fluidized bed through slurry pipes to form coal slime blocks.

[0051] It is understood that the preset moisture content in the embodiments of this application can be set to 30%.

[0052] Specifically, in this embodiment of the application, based on the parameters of the combustion reaction, coal slime with a moisture content of about 30% from the coal washing plant is transported to the top of the circulating fluidized bed boiler by the coal slime feeding system 200, i.e., the feeding system, and the coal slime on the top of the boiler falls into the furnace of the circulating fluidized bed along the slurry pipe to form coal slime blocks.

[0053] Optionally, in one embodiment of this application, the coal slime feeding system 200 includes: an execution unit for performing at least one of the following actions on the coal slime under a preset furnace temperature condition: drying, agglomeration, volatilization, thermal explosion, combustion, and falling, to form coal slime blocks.

[0054] In actual implementation, the embodiments of this application can use coal slime with a moisture content of approximately 30% from the coal washing plant, which is transported to the top of the furnace by the feeding system and falls into the furnace along the slurry pipe. The falling coal slime meets the high temperature (900-960℃) of the furnace and undergoes stages such as drying, agglomeration, volatilization, thermal explosion, combustion, and falling. This process is suspension combustion, through which large coal slime blocks are broken into blocks of different sizes.

[0055] (1) The coal slime feeding system 200 includes: Pipelines are the primary means of transporting coal slurry. Long-distance pipelines are crucial for coal slurry combustion. The slurry transportation system utilizes a viscous material pipeline system, which solves a series of technical problems in long-distance pipelines, including slurry flow control, pipeline sealing vibration, pipeline wear, slurry preparation, storage, mixing, transportation, feeding, and cleaning. This system enables a fully enclosed, stable, long-distance, and pollution-free transportation process.

[0056] In one embodiment of this application, the following two formulas are coupled together to calculate the pipe diameter and the average flow velocity of the coal slurry based on the amount of coal slurry:

[0057]

[0058] in, The Reynolds number is... The desired flow rate for a circulating fluidized bed boiler. The density of coal slime, and These are rheological property parameters. D This refers to the inner diameter of the pipe.

[0059] (2) Furnace system design: The furnace is an important component of the circulating fluidized bed.

[0060] The materials entering the furnace include fuel, bed material, desulfurizing agent, and gases. At the same time, some solid substances and gases leave the furnace, including ash from the furnace bottom, recycled materials, and flue gas.

[0061] Based on the heat exchange characteristics within the furnace, the heat transfer equation for a circulating fluidized bed boiler is as follows:

[0062]

[0063]

[0064] in, B j Fuel consumption, kg / s; The heat transferred per kilogram of combustion products to the furnace heating surfaces and materials, in kJ; The insulation coefficient; The effective value of heat release is expressed in kJ / kg. X For valid values The share; The enthalpy of ash at the furnace outlet is given in kJ / kg. The enthalpy of the furnace mouth ash is expressed in kJ / kg. B s The circulating ash amount is expressed in kg / s. The enthalpy of the flue gas at the furnace outlet is given in kJ / kg. The furnace heat transfer coefficient is given by kJ / (m²). 2 s℃); The furnace heating surface area, Furnace opening temperature, °C; The tube wall temperature at the water-cooled wall is in °C. The excess air coefficient at the furnace outlet is expressed in kJ / kg. The excess air coefficient at the return valve inlet; , These are the enthalpy of hot air and the enthalpy of cold air, respectively, in kJ / kg; The boiler thermal efficiency equation is:

[0065] in, For boiler thermal efficiency; Q 2 represents the flue gas heat loss per kilogram of fuel, in kJ; Q 3 represents the heat loss from combustion of combustible gas per kilogram of fuel, in kJ; Q 4 represents the heat loss per kilogram of solid fuel from incomplete combustion, in kJ; Q 5 represents the heat loss per kilogram of fuel, in kJ; Q 6 represents the slag heat loss per kilogram of fuel, in kJ; Q7 represents the desulfurization heat loss per kilogram of fuel, in kJ; It is the heat input per kilogram of fuel, in kJ.

[0066] Among the key parameters of the furnace, bed temperature is one of the critical parameters of the suspension-fluidized-circulating fluidized bed combustion system. The design temperature should avoid ash softening and coking, improve combustion efficiency, and reduce the emission of fly ash carbon and N2O. In addition, coal slime is difficult to burn and volatilize, so the bed temperature is designed to be 900-960℃.

[0067] The in-furnace heat transfer coefficient of a circulating fluidized bed boiler is:

[0068] in, k The heat transfer coefficient is expressed in kW / m³. 2 ; k 0 is a ratio; A and B It is a constant coefficient; The concentration of suspended particles is kg / m³. 3 ; T This represents the average temperature inside the furnace. Material concentration is the biggest factor affecting the heat transfer coefficient of the combustion heating surface inside the furnace; the higher the material concentration, the higher the heat transfer coefficient.

[0069] The secondary air system 300 is used to control the rotation of coal slurry blocks and control the suspension combustion of coal slurry blocks to form unburned blocks when asymmetrical secondary air flows on both sides of the furnace wall.

[0070] It is understandable that the correct selection of furnace fluidization velocity in the embodiments of this application is also important for slurry combustion. Fluidization velocity is generally determined through fluidized bed cold state test.

[0071] In actual implementation, the asymmetric secondary air in this embodiment is designed to flow on both sides of the furnace wall. With the asymmetric secondary air flowing on both sides of the furnace wall, the falling coal slurry blocks rotate, thereby prolonging the falling time and path of the coal slurry blocks, allowing them to complete suspension combustion and form unburned blocks.

[0072] In this application embodiment, a secondary air system design can be implemented. If the fuel and air are not mixed evenly, it will affect the boiler's thermal efficiency and combustion efficiency. Under the premise of ensuring boiler pressure, such as... Figure 3 As shown, the multi-stage asymmetric design of the secondary air system allows oxygen to be delivered to the furnace as the slurry blocks fall during their S-shaped rotation. This design avoids the oxygen-deficient zone, extends the descent time and path of the coal slime, and ensures combustion and desulfurization efficiency.

[0073] Optionally, in one embodiment of this application, the low-load coal blending device 10 based on a circulating fluidized bed boiler further includes: a suspension combustion module, used to generate the final suspension combustion result when unburned blocks fall onto the surface of the circulating fluidized bed and float above the coal gangue; and an internal circulation fluidized combustion module, used to crush, wear, break, aggregate, rise, sink, disperse, and burn off the unburned blocks based on the final suspension combustion result to obtain the internal circulation fluidized combustion result.

[0074] It is understood that the unburned block in the embodiments of this application may be a partially unburned block.

[0075] In this embodiment, the suspension combustion module generates the final suspension combustion result when the unburned blocks fall onto the surface of the circulating fluidized bed and float above the coal gangue. Based on the final suspension combustion result, the internal circulation fluidized combustion module crushes, wears, breaks, aggregates, rises, sinks, disperses, and burns off some of the unburned blocks to complete the internal circulation fluidized combustion process and obtain the internal circulation fluidized combustion result.

[0076] The embodiments of this application can further extend the descent time and path of coal slime, ensuring combustion efficiency and desulfurization efficiency.

[0077] Separator 400 is used to separate unburned blocks and flue gas into gas and solids to obtain separated gas and separated solids.

[0078] It is understood that the separated solids in the embodiments of this application include bed material and unburned block material.

[0079] In actual implementation, the remaining part of the unburned block in this embodiment enters the separator 400, i.e., the cyclone separator, together with the flue gas for gas-solid separation. After the separated gas enters the rear flue, the separated ash is transported to the ash silo after passing through the electrostatic precipitator.

[0080] The embodiments of this application can perform gas-solid separation of unburned blocks and flue gas, providing support for the next combustion cycle.

[0081] The return feeder 500 is used to return the separated gas and separated solids to the circulating fluidized bed boiler for a new combustion cycle, generating combustion cycle results.

[0082] In actual implementation, the embodiments of this application can return the separated gas and separated solids to the circulating fluidized bed boiler through the return feeder 500 to enter the next combustion cycle. This process is external circulation fluidized combustion, generating combustion cycle results.

[0083] The embodiments of this application can return the separated gas and separated solids to the circulating fluidized bed boiler, thereby significantly extending the residence time of fuel and desulfurizing agent in the furnace and greatly improving the burnout rate and overall combustion efficiency.

[0084] The coal blending module 600 is used to obtain the energy fluctuation of coal slime by utilizing the energy storage of the circulating fluidized bed boiler based on the combustion cycle results, and to control the coal slime ratio of the circulating fluidized bed boiler according to the energy fluctuation to generate coal blending results that meet the preset low load conditions.

[0085] In actual implementation, the embodiments of this application can run the control model: (1) Energy fluctuations caused by coal slime: In the above experiments, the moisture content of the coal slime in each pump was strictly controlled within a certain range. Therefore, the input energy did not change significantly during operation, making it easy to achieve automatic combustion control. However, it is difficult to ensure that the moisture content of the coal slime remains constant during long-term operation. When fuel is mixed in the hopper or injected by the pump, some water will mix into the coal slime. Since the pump volume is constant, if the proportion of water is too high, the amount of coal slime will be lower than normal, which is called a high-moisture pump condition. Conversely, it is called a low-moisture pump condition.

[0086] Under steady-state load, the typical coal slime pumping process can be divided into three types: 1. The normal operation process of the coal slime pump, where the coal slime-to-water ratio is maintained at the design value. During combustion, some energy is absorbed by the water. 2. The operation process of the high-humidity pump, where the moisture content is higher than normal, resulting in less total energy released by the coal than in process 1, while the water absorbs more energy. The net input energy is less than the required energy, and boiler energy storage must be used to compensate for the insufficient input energy. 3. The operation process of the low-moisture-content pump, where the moisture content is lower than normal. Conversely, the total energy provided by the coal is more than in process 1, while the water absorbs less energy. Therefore, the net input energy is greater than the required energy, requiring excessive input energy to stabilize boiler parameters. In actual operation, all three processes occur randomly. Obviously, the fluctuations caused by this randomness increase with the increase of the coal slime blending ratio.

[0087] (2) Energy storage theory: To achieve long-term stability of the unit, it is important to improve the unit's energy conversion. By utilizing the boiler's own energy storage to mitigate parameter fluctuations after co-firing coal slime, the operating performance of the high coal slime ratio circulating fluidized bed boiler can be improved.

[0088] Unlike pulverized coal boilers, circulating fluidized bed boilers release most of their heat not from the instantaneous input of fuel, but from a large amount of unburned carbon. This carbon is stored in the bed material and circulates continuously within the furnace; it is called "burned carbon." Therefore, circulating fluidized bed boilers have a very large energy storage capacity.

[0089] In one embodiment of this application, according to the law of conservation of mass, the in-furnace carbon combustion formula for a circulating fluidized bed boiler is:

[0090] in, Carbon burned, in kg; The fuel feed rate, including coal and coal slime, is expressed in kg / s. To receive net carbon, % ρ represents the combustion rate of carbon, in kg / s; The average carbon content of the slag, % Slag discharge rate, kg / s; The average carbon content of fly ash is %; The input rate of fly ash is expressed in kg / s. Based on engineering experience, a constant is set for a certain period of time. and .

[0091] The combustion rate of carbon can be expressed as:

[0092] in, is the molar mass of carbon, kg / kmol; The oxygen concentration around the "burning carbon" is expressed in kmol / m3. The average particle diameter is in meters (m). Density of carbon particles, kg / m³ 3 ; This is the particle combustion rate constant, which is related to the bed temperature.

[0093] in, T The temperature is K.

[0094] Assuming the oxygen concentration of particles is directly proportional to the total air volume:

[0095] in, This is the correlation coefficient between oxygen concentration and total airflow rate. The total airflow rate is Nm 3 / s.

[0096] According to the above formula, the heat released by burning carbon can be expressed as:

[0097] in, The energy released by the combustion of carbon, in MJ / s; , where is the calorific value of carbon, in MJ / kg; These are the total coefficients of the model.

[0098] The main volatile components in fuels are CH4, H2, CO, and tar (CH4). 0.689 O 0.014 The components are CO2 and H2O, of which the first four are combustible. The mass fraction of each component can be calculated using the following formula:

[0099]

[0100]

[0101]

[0102] in, M V The mass fraction of volatiles in the fuel, %.

[0103] The heat release from volatile combustion can be expressed by the following formula:

[0104] in, The heat released during volatile combustion, expressed in MJ / s; The mass fraction of each component; H i This corresponds to the calorific value.

[0105] Total heat of combustion released in the furnace Q(t) It can be calculated using the following formula:

[0106] Fuel-side energy storage can be expressed as:

[0107] Research on energy storage on the steam drum side is relatively mature, and the steam drum pressure is generally selected. P d This is used to measure the balance of energy storage on the steam drum side of a subcritical unit.

[0108]

[0109] in, The pressure of the steam drum is (MPa). Defined as the heat storage coefficient of the steam drum.

[0110] Based on the quantized total calorific value of the furnace combustion and the energy storage on the fuel side and steam drum side, the boiler energy storage distribution can be accurately calculated, improving energy conversion. Under the premise of meeting variable load requirements, when the air-coal ratio is reasonable and energy fluctuations caused by coal slime are reduced through control measures, more efficient boiler energy storage utilization can be achieved, thus making it possible to increase the amount of coal slime burned.

[0111] Energy fluctuations caused by coal slime combustion are a major cause of operational instability in circulating fluidized bed (CFB) boilers. Based on energy storage theory, a novel load control strategy is proposed to improve the operational performance of CFB boilers with high coal slime ratios. This application, based on energy storage theory, proposes a novel load control strategy to improve the operational control stability of CFB boilers with high coal slime ratios, thereby enhancing their combustion performance, coal slime mixing ratio, and overall operational performance.

[0112] Optionally, in one embodiment of this application, the coal blending module 600 includes: a composition unit for composing a first feedforward control sub-signal of coal slime through a differential program and a proportional component; an adjustment unit for eliminating the main steam pressure deviation based on the first feedforward control sub-signal and using a second control sub-signal of coal slime to adjust the load demand and obtain the energy fluctuation of coal slime; a suppression unit for suppressing the energy fluctuation of coal slime using a third sub-signal of coal slime in the early stage of the energy fluctuation of coal slime and generating a suppression result; and a control unit for performing PI feedback supplementary control of the air-coal ratio based on the suppression result and using a fourth sub-signal of coal slime to generate a coal blending result that meets the preset low load conditions.

[0113] It is understandable that this application embodiment proposes a load control strategy to approach the upper limit of the coal slime mix ratio as closely as possible during actual operation. The overall design idea is to fully utilize the energy storage of the circulating fluidized bed boiler to stabilize energy fluctuations caused by coal slurry, while meeting load requirements. Based on the analysis of energy fluctuations caused by coal slime moisture content, this application embodiment improves the load control strategy of the circulating fluidized bed unit, such as... Figure 4 As shown, the fuel-side energy storage is fully utilized to minimize the deviation between input energy, stored energy and demand energy; in the embodiments of this application, the first feedforward control sub-signal can be feedforward control sub-signal 1, the second control sub-signal can be control sub-signal 2, the third sub-signal can be sub-signal 3, and the fourth sub-signal can be sub-signal 4.

[0114] In actual implementation, the load control command in this embodiment consists of four parts. The load command signal, composed of differential and proportional components, serves as feedforward control sub-signal 1, primarily acting in the early control phase to improve the unit's load response speed. Control sub-signal 2 eliminates main steam pressure deviations through a PI controller, adjusting load demand and reducing energy fluctuations caused by coal slime. Sub-signals 3 and 4 are the core of the control strategy. Energy storage utilization is divided into two parts. Sub-signal 3 operates in the early stage of coal slime energy fluctuations, its task being to suppress fluctuations using boiler energy storage. Sub-signal 4 operates in the later stage, with boiler energy storage supplemented by PI feedback control based on the air-to-coal ratio, where the air-to-coal ratio is the ratio of the amount of air entering the boiler to the amount of coal.

[0115] Energy storage The acceleration signal is constructed as follows, which represents a portion of the stored energy to balance the energy fluctuations caused by the coal slime:

[0116] Furthermore, the embodiments of this application allow for controller tuning. Dynamic thermal effects with a feedforward structure do not affect system stability. Controller settings are still determined by engineering configuration methods. The specific steps for controller tuning of the load control system are as follows: 1) Single-loop coarse adjustment First, the load control system is divided into three single loops, namely... and The controller tuning for each single loop is based on the 4:1 attenuation curve method. This method may require some engineering experience, but it is very useful.

[0117] 2) Fine-tuning of the entire load control system To eliminate fluctuations caused by coupling between single loops, the entire load control system should be in an automatic state without sub-signals 3 and 4. The controller parameters can be fine-tuned based on engineering experience.

[0118] 3) Tuning of sub-signals 3 and 4 The final step is to add and tune sub-signals 3 and 4. During dynamic tuning, the acceleration signal of the pneumatic control loop should primarily operate in the early stage due to its fast response. The acceleration signal of the fuel control loop should operate at a slower speed. Furthermore, the influence of each PI closed loop can be appropriately reduced, while decreasing overshoot and integral saturation.

[0119] Figure 4 The parameters are represented as follows. Table 1 shows the important control parameter values ​​for the control strategy, as shown in Table 1: Table 1

[0120] The low-load coal blending device based on a circulating fluidized bed (CFB) boiler proposed in this application addresses the problems of low boiler thermal efficiency, combustion efficiency, and coal slurry mixing ratio in CFB boiler combustion technology. It proposes a novel combustion technology and, based on energy storage theory, proposes a new load control strategy to improve the operating performance of CFB boilers with high coal slurry ratios, addressing the energy fluctuations caused by coal slurry combustion that lead to operational instability in CFB boilers. This solves the problems of related technologies focusing on high-load blending of inferior coal conditions, with limited research on low-load, high-proportion blending of inferior coal conditions, and the current trend of focusing on small blending ratios while neglecting high-proportion blending of inferior coal.

[0121] Next, referring to the accompanying drawings, a low-load coal blending and co-firing method based on a circulating fluidized bed boiler, according to an embodiment of this application, is described.

[0122] like Figure 5 As shown, the low-load coal blending method based on a circulating fluidized bed boiler includes the following steps: In step S501, raw coal is gasified and burned under a preset low air equivalence ratio condition to generate a gas-solid binary fuel composed of coal gas and char that meets the preset high temperature conditions. The gas-solid binary fuel is then introduced into a circulating fluidized bed boiler for combustion reaction to generate combustion reaction parameters.

[0123] In step S502, based on the parameters of the combustion reaction, coal slurry with a preset moisture content is transported to the top of the circulating fluidized bed boiler, and the coal slurry on the top of the boiler falls into the furnace of the circulating fluidized bed along the slurry pipe to form coal slurry blocks.

[0124] In step S503, with asymmetrical secondary air flowing on both sides of the furnace wall, the coal slurry blocks are controlled to rotate and to undergo suspension combustion to form unburned blocks.

[0125] In step S504, the unburned block and flue gas are separated into gas and solid to obtain separated gas and separated solid.

[0126] In step S505, the separated gas and separated solids are returned to the circulating fluidized bed boiler to carry out a new combustion cycle and generate a combustion cycle result.

[0127] In step S506, based on the combustion cycle results, the circulating fluidized bed boiler is used to store energy to obtain the energy fluctuation of the coal slime, and the coal slime ratio of the circulating fluidized bed boiler is controlled according to the energy fluctuation to generate a blended coal combustion result that meets the preset low load conditions.

[0128] Optionally, in one embodiment of this application, coal slurry with a preset moisture content is transported to the top of a circulating fluidized bed boiler, and the coal slurry on the top of the boiler falls into the furnace of the circulating fluidized bed along a slurry pipe to form coal slurry blocks. This includes performing at least one of the following actions on the coal slurry under a preset furnace temperature: drying, agglomeration, volatilization, thermal explosion, combustion, and falling, to form coal slurry blocks.

[0129] Optionally, in one embodiment of this application, the method further includes: generating a final suspension combustion result when the unburned blocks fall onto the surface of the circulating fluidized bed and float above the coal gangue; based on the final suspension combustion result, the unburned blocks are crushed, worn, broken, aggregated, lifted, sunk, dispersed, and burned off to obtain an internal circulating fluidized combustion result. Optionally, in one embodiment of this application, it further includes: conveying coal gangue particles that meet preset high-density conditions to the bottom of the fluidized bed.

[0130] Optionally, in one embodiment of this application, the average flow velocity of the coal slime is:

[0131]

[0132] in, The Reynolds number is... The desired flow rate for a circulating fluidized bed boiler. The density of coal slime, and These are rheological property parameters. D This refers to the inner diameter of the pipe. The in-furnace heat transfer equation for a circulating fluidized bed boiler is:

[0133]

[0134]

[0135] in, Fuel consumption The amount of heat transferred per kilogram of combustion products to the furnace heating surfaces and materials. For insulation coefficient, To determine the effective value of heat release, X For valid values share, The enthalpy of ash at the furnace outlet. For the enthalpy of ash at the furnace mouth, For circulating ash quantity, The enthalpy of the flue gas at the furnace outlet. k m The furnace heat transfer coefficient, The furnace heating surface area, The furnace opening temperature, This refers to the tube wall temperature at the water-cooled wall. The excess air coefficient at the furnace outlet. The excess air coefficient at the return valve inlet. , These are the enthalpy of hot air and the enthalpy of cold air, respectively. The in-furnace heat transfer coefficient of a circulating fluidized bed boiler is:

[0136] in, The heat transfer coefficient, k 0 represents the ratio. A and B All are constant coefficients. The concentration of suspended particles. T This represents the average temperature inside the furnace.

[0137] Optionally, in one embodiment of this application, the in-furnace carbon combustion formula of the circulating fluidized bed boiler is:

[0138] in, For the amount of carbon burned, For fuel feed rate, To receive basic net carbon, The rate of carbon combustion. This refers to the average carbon content of the slag. For slag removal rate, This represents the average carbon content of fly ash. This represents the fly ash input rate.

[0139] Optionally, in one embodiment of this application, the low-load coal blending module includes: a first feedforward control sub-signal composed of a differential program and a proportional component; based on the first feedforward control sub-signal, a second control sub-signal of the coal slime is used to eliminate the main steam pressure deviation in order to adjust the load demand and obtain the energy fluctuation of the coal slime; in the early stage of the energy fluctuation of the coal slime, a third sub-signal of the coal slime is used to suppress the energy fluctuation of the coal slime and generate a suppression result; based on the suppression result, a fourth sub-signal of the coal slime is used to perform PI feedback supplementary control of the air-coal ratio to generate a coal blending result that meets the preset low-load conditions.

[0140] It should be noted that the foregoing explanation of the embodiment of the low-load coal blending and co-firing device based on the circulating fluidized bed boiler also applies to the low-load coal blending and co-firing method based on the circulating fluidized bed boiler in this embodiment, and will not be repeated here.

[0141] The low-load coal blending method based on a circulating fluidized bed (CFB) boiler proposed in this application addresses the problems of low boiler thermal efficiency, combustion efficiency, and coal slurry mixing ratio in CFB boiler combustion technology. It proposes a novel combustion technology and, based on energy storage theory, proposes a new load control strategy to improve the operating performance of CFB boilers with high coal slurry ratios, addressing the energy fluctuations caused by coal slurry combustion that lead to operational instability in CFB boilers. This solves the problems of related technologies focusing on high-load blending of inferior coal conditions, with limited research on low-load, high-proportion blending of inferior coal conditions, and the current trend of focusing on small blending ratios while neglecting high-proportion blending of inferior coal.

[0142] Figure 6 A schematic diagram of the structure of an electronic device provided in an embodiment of this application. The electronic device may include: The memory 601, the processor 602, and the computer program stored on the memory 601 and capable of running on the processor 602.

[0143] When the processor 602 executes the program, it implements the low-load coal blending method based on a circulating fluidized bed boiler provided in the above embodiments.

[0144] Furthermore, electronic devices also include: Communication interface 603 is used for communication between memory 601 and processor 602.

[0145] The memory 601 is used to store computer programs that can run on the processor 602.

[0146] The memory 601 may include high-speed RAM memory, and may also include non-volatile memory, such as at least one disk storage device.

[0147] If the memory 601, processor 602, and communication interface 603 are implemented independently, then the communication interface 603, memory 601, and processor 602 can be interconnected via a bus to complete communication between them. The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus, etc. Buses can be categorized as address buses, data buses, control buses, etc. For ease of representation, Figure 6 The bus is represented by a single thick line, but this does not mean that there is only one bus or one type of bus.

[0148] Optionally, in a specific implementation, if the memory 601, processor 602, and communication interface 603 are integrated on a single chip, then the memory 601, processor 602, and communication interface 603 can communicate with each other through an internal interface.

[0149] The processor 602 may be a central processing unit (CPU), an application specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of this application.

[0150] This embodiment also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described low-load coal blending method based on a circulating fluidized bed boiler.

[0151] 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.

[0152] 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, "N" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0153] Any process or method described in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or N executable instructions for implementing custom logic functions or processes, and the scope of the preferred embodiments of this application includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the functions involved, as should be understood by those skilled in the art to which embodiments of this application pertain.

[0154] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include: an electrical connection having one or more wires (electronic device), a portable computer disk drive (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Alternatively, the computer-readable medium may be paper or other suitable media on which the program can be printed, since the program can be obtained electronically by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in a computer memory.

[0155] It should be understood that the various parts of this application can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, the N steps or methods can be implemented using software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0156] Those skilled in the art will understand that all or part of the steps of the methods in the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, the program includes one or a combination of the steps of the method embodiments.

[0157] Furthermore, the functional units in the various embodiments of this application can be integrated into a processing module, or each unit can exist physically separately, or two or more units can be integrated into a module. The integrated module can be implemented in hardware or as a software functional module. If the integrated module is implemented as a software functional module and sold or used as an independent product, it can also be stored in a computer-readable storage medium.

[0158] The storage medium mentioned above can be a read-only memory, a disk, or an optical disk, etc. Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of this application.

Claims

1. A low-load coal blending and co-firing device based on a circulating fluidized bed boiler, characterized in that, include: The preheating and modification device is used to gasify and burn raw coal under a preset low air equivalence ratio condition to generate a gas-solid binary fuel composed of coal gas and char that meets the preset high temperature conditions. The gas-solid binary fuel is then introduced into a circulating fluidized bed boiler for combustion reaction to generate combustion reaction parameters. A coal slime feeding system is used to transport coal slime with a preset moisture content to the top of the circulating fluidized bed boiler based on the parameters of the combustion reaction, and to drop the coal slime from the top of the boiler into the furnace of the circulating fluidized bed through a slurry pipe to form coal slime blocks. The secondary air system is used to control the rotation of the coal slime blocks and to control the coal slime blocks to undergo suspension combustion in the presence of asymmetrical secondary air flowing on both sides of the furnace wall, so as to form unburned blocks. A separator is used to perform gas-solid separation between the unburned blocks and the flue gas to obtain separated gas and separated solids; A return feeder is used to return the separated gas and the separated solids to the circulating fluidized bed boiler for a new combustion cycle, generating a combustion cycle result; The coal blending module is used to obtain the energy fluctuation of the coal slime by utilizing the energy storage of the circulating fluidized bed boiler based on the combustion cycle results, and to control the coal slime ratio of the circulating fluidized bed boiler according to the energy fluctuation, so as to generate a coal blending result that meets the preset low load conditions.

2. The low-load coal blending and co-firing device based on a circulating fluidized bed boiler according to claim 1, characterized in that, The coal slime feeding system includes: An execution unit is used to perform at least one of the following actions on the coal slime under a preset furnace temperature condition: drying, agglomeration, volatilization, thermal explosion, combustion, and falling, in order to form the coal slime block.

3. The low-load coal blending and co-firing device based on a circulating fluidized bed boiler according to claim 1, characterized in that, Also includes: The suspension combustion module is used to generate the final suspension combustion result when the unburned blocks fall onto the surface of the circulating fluidized bed and the unburned blocks float above the coal gangue. The internal circulation fluidized combustion module is used to break up, wear down, crush, aggregate, rise, sink, disperse and burn out the unburned blocks based on the final suspension combustion result, so as to obtain the internal circulation fluidized combustion result.

4. The low-load coal blending and co-firing device based on a circulating fluidized bed boiler according to claim 1, characterized in that, Also includes: The bed material conveying system is used to convey coal gangue particles that meet the preset high-density conditions to the bottom of the fluidized bed.

5. The low-load coal blending and co-firing device based on a circulating fluidized bed boiler according to claim 1, characterized in that, The average flow velocity of the coal slime is: in, Let Reynolds number be 1. The desired flow rate of the circulating fluidized bed boiler. The density of coal slime, and These are rheological property parameters. D This refers to the inner diameter of the pipe. The in-furnace heat transfer equation for the circulating fluidized bed boiler is as follows: in, Fuel consumption The amount of heat transferred per kilogram of combustion products to the furnace heating surfaces and materials. For insulation coefficient, To determine the effective value of heat release, X For valid values share, The enthalpy of ash at the furnace outlet. For the enthalpy of ash at the furnace mouth, For circulating ash quantity, The enthalpy of the flue gas at the furnace outlet. k m The furnace heat transfer coefficient, The furnace heating surface area, The furnace opening temperature, The tube wall temperature at the water-cooled wall. The excess air coefficient at the furnace outlet. The excess air coefficient at the return valve inlet. , These are the enthalpy of hot air and the enthalpy of cold air, respectively. The in-furnace heat transfer coefficient of the circulating fluidized bed boiler is: in, The heat transfer coefficient is... k 0 represents the ratio. A and B All are constant coefficients. The concentration of suspended particles. T This represents the average temperature inside the furnace.

6. The low-load coal blending and co-firing device based on a circulating fluidized bed boiler according to claim 1, characterized in that, The in-furnace carbon combustion formula for the circulating fluidized bed boiler is: in, For the amount of carbon burned, For fuel feed rate, To receive basic net carbon, The rate of carbon combustion. This refers to the average carbon content of the slag. For slag removal rate, This represents the average carbon content of fly ash. This represents the fly ash input rate.

7. The low-load coal blending and co-firing device based on a circulating fluidized bed boiler according to claim 1, characterized in that, The coal blending module includes: The constituent unit is used to compose the first feedforward control sub-signal of the coal slime through differential procedure and proportional component; The regulating unit is used to eliminate the main steam pressure deviation based on the first feedforward control sub-signal and the second control sub-signal of the coal slime, so as to regulate the load demand and obtain the energy fluctuation of the coal slime. The suppression unit is used in the early stage of energy fluctuation of the coal slime to suppress the energy fluctuation of the coal slime using the third sub-signal of the coal slime and generate a suppression result. The control unit is used to perform PI feedback supplementary control of the air-coal ratio based on the suppression result and the fourth sub-signal of the coal slime to generate the blended coal combustion result that meets the preset low load conditions.

8. A low-load coal blending and co-firing method based on a circulating fluidized bed boiler, characterized in that, Includes the following steps: Raw coal is gasified and burned under a preset low air equivalence ratio to generate a gas-solid binary fuel composed of coal gas and char that meets the preset high temperature conditions. The gas-solid binary fuel is then introduced into a circulating fluidized bed boiler for combustion reaction to generate combustion reaction parameters. Based on the parameters of the combustion reaction, coal slurry with a preset moisture content is transported to the top of the circulating fluidized bed boiler, and the coal slurry on the top of the boiler falls into the furnace of the circulating fluidized bed along the slurry pipe to form coal slurry blocks. With asymmetrical secondary air flowing on both sides of the furnace wall, the coal slime blocks are controlled to rotate and to undergo suspension combustion to form unburned blocks. The unburned block and flue gas are subjected to gas-solid separation to obtain separated gas and separated solid; The separated gas and the separated solids are returned to the circulating fluidized bed boiler to carry out a new combustion cycle and generate a combustion cycle result; Based on the combustion cycle results, the circulating fluidized bed boiler is used to store energy to obtain the energy fluctuation of the coal slime, and the coal slime ratio of the circulating fluidized bed boiler is controlled according to the energy fluctuation to generate a blended coal combustion result that meets the preset low load conditions.

9. An electronic device, characterized in that, include: The memory, the processor, and the computer program stored in the memory and executable on the processor, the processor executing the program to implement the low-load coal blending method based on a circulating fluidized bed boiler as described in claim 8.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, The program is executed by the processor to implement the low-load coal blending method based on a circulating fluidized bed boiler as described in claim 8.

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