An experimental system and method for studying coal and biomass coupled combustion characteristics

Abstract

The present application relates to clean coal combustion and biomass energy utilization technical field, specifically disclose a kind of for coal and biomass coupling combustion characteristic research experimental system and method, including multiway gas distribution module, feeding module, fluidized bed reactor, heating module, gas-solid separation module, flue gas dewatering module and flue gas analysis module;Feeding module is connected with multiway gas distribution module, multiway gas distribution module is connected with the bottom of fluidized bed reactor, feeding module is connected with the lateral wall of fluidized bed reactor, heating module is sleeved in the radial outer side of fluidized bed reactor, gas-solid separation module is connected with the top of fluidized bed reactor, flue gas dewatering module is connected with gas-solid separation module, flue gas analysis module is connected with flue gas dewatering module.The present application can realize flow, pressure, temperature field, flue gas concentration and other multidimensional parameters synchronous acquisition, cleaning and analysis, effectively solve traditional platform feeding instability, atmosphere uneven, temperature sheet, data out of sync and other problems.

Description

Technical Field

[0001] This invention relates to the field of clean coal combustion and biomass energy utilization technology, specifically to an experimental system and method for studying the coupled combustion characteristics of coal and biomass. Background Technology

[0002] Coal is my country's core energy source, long serving as a crucial component in power supply, industrial production, and energy security. However, traditional coal-fired methods suffer from low combustion efficiency, high carbon emissions, and excessive SO2 and NO emissions. x The large volume of pollutant emissions and the prominent issues of ecological pollution and energy loss have made the clean, efficient, and low-carbon utilization of coal a key research direction in the energy sector. Biomass possesses advantages such as renewability, carbon neutrality, low sulfur and nitrogen content, and high reactivity. Co-combustion of coal and biomass can combine these advantages, effectively improving combustion efficiency and reducing pollutant emissions. It is a key technology for the clean utilization of coal and the high-value utilization of biomass, and a current research hotspot in the energy and environment fields. Fluidized bed combustion technology, adapted for multi-fuel co-combustion, is a core experimental method for studying the mechanism of coal / biomass coupled combustion and the laws governing pollutant formation.

[0003] Existing fluidized bed experimental platforms still suffer from numerous technical shortcomings, making it difficult to meet the demands of high-precision experiments. Conventional feeding structures are prone to bridging, blockage, and feed rate fluctuations due to differences in fuel properties, resulting in poor experimental repeatability. Direct injection of multiple gases into the furnace leads to insufficient mixing, resulting in uneven atmosphere distribution, fluctuating fluidization states, and low experimental accuracy. The limited number of furnace temperature measurement points fails to cover the entire axial temperature distribution, making it difficult to meet the needs of multi-stage combustion mechanism research. Furthermore, existing equipment has insufficient flue gas pretreatment capabilities; fly ash and water vapor easily interfere with detection accuracy and wear down instruments. The coordination between flue gas treatment, detection, and fly ash collection modules is poor, leading to inadequate data synchronization. In addition, data acquisition from various detection devices is scattered, lacking a unified management platform, making simultaneous and refined analysis of multiple parameters impossible. Moreover, it only possesses post-monitoring functions, unable to predict pollutant generation trends, and combustion control exhibits lag. In summary, a novel experimental system and method for studying the coupled combustion characteristics of coal and biomass are urgently needed to address the problems existing in the current technology. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention provides an experimental system and method for studying the coupled combustion characteristics of coal and biomass. It enables continuous and stable feeding, precise control of the combustion atmosphere, online monitoring of multiple temperatures, efficient separation of fly ash, real-time analysis of flue gas, and simultaneous acquisition of experimental data, improving the stability and accuracy of the experimental process. This provides a reliable experimental platform for studying the coupled combustion mechanism of coal and biomass, analyzing pollutant formation characteristics, and optimizing the combustion process. To achieve the above objectives, this invention adopts the following technical solution:

[0005] In a first aspect, an experimental system for studying the coupled combustion characteristics of coal and biomass according to some embodiments of this application includes:

[0006] A multi-channel gas distribution module, which is used to store and provide the gas required for the experiment;

[0007] The feeding module is connected to the multi-channel gas distribution module and is used to store and provide the coal and biomass required for the experiment.

[0008] A fluidized bed reactor, wherein the multi-channel gas distribution module is connected to the bottom of the fluidized bed reactor, and the feeding module is connected to the side wall of the fluidized bed reactor, and the fluidized bed reactor is used to provide a reaction site for experiments;

[0009] A heating module is fitted radially outside the fluidized bed reactor and is used to heat the fluidized bed reactor.

[0010] A gas-solid separation module is connected to the top of the fluidized bed reactor and is used to separate the gas-solid mixture after the reaction.

[0011] A flue gas water removal module is connected to the gas-solid separation module and is used to remove moisture from the flue gas.

[0012] A flue gas analysis module is connected to the flue gas dehydration module, and the flue gas analysis module is used to analyze the composition of the flue gas and the concentration of each component.

[0013] An experimental system for studying the coupled combustion characteristics of coal and biomass according to some embodiments of this application includes a multi-channel gas distribution module comprising an air compressor, an Ar gas cylinder, an O2 gas cylinder, a CO2 gas cylinder, and a gas mixing chamber. The air compressor is connected to the feeding module via a feed gas pipeline, and the air compressor is connected to the gas mixing chamber via an air intake pipeline. The Ar gas cylinder is connected to the gas mixing chamber via an argon gas intake pipeline, the O2 gas cylinder is connected to the gas mixing chamber via an oxygen intake pipeline, the CO2 gas cylinder is connected to the gas mixing chamber via a carbon dioxide intake pipeline, and the gas mixing chamber is connected to the bottom of the fluidized bed reactor via an intake pipeline.

[0014] An experimental system for studying the coupled combustion characteristics of coal and biomass according to some embodiments of this application includes an air inlet pipe equipped with an air flow meter, an argon inlet pipe equipped with an argon flow meter, an oxygen inlet pipe equipped with an oxygen flow meter, and a carbon dioxide inlet pipe equipped with a carbon dioxide flow meter.

[0015] An experimental system for studying the coupled combustion characteristics of coal and biomass according to some embodiments of this application includes a feeding module comprising a silo, a pressure gauge, and a screw feeder. The silo is equipped with an upper stirring mechanism and a lower stirring mechanism. The upper stirring mechanism continuously agitates the coal and biomass, while the lower stirring mechanism pre-loosens the coal and biomass in the feeding section. The pressure gauge is located at the top of the silo. The bottom outlet of the silo is connected to the inlet of the screw feeder. A vibration assembly is provided at the connection between the silo and the screw feeder. The outlet of the screw feeder is connected to the side wall of the fluidized bed reactor via a downwardly inclined feed pipe.

[0016] An experimental system for studying the coupled combustion characteristics of coal and biomass according to some embodiments of this application includes a fluidized bed reactor with an air inlet, a feed inlet, an exhaust outlet, and thermocouples. The air inlet is located at the bottom of the fluidized bed reactor, and the gas mixing chamber is connected to the air inlet via the air inlet pipe. The feed inlet is located on the side wall of the fluidized bed reactor at a distance of one-sixth to one-fifth of the axial height of the fluidized bed reactor from the air inlet. The outlet of the screw feeder is connected to the feed inlet via the feed pipe. The exhaust outlet is located at the top of the fluidized bed reactor and is connected to the gas-solid separation module via the exhaust pipe. Multiple thermocouples are arranged inside the side wall of the fluidized bed reactor along the axial height of the fluidized bed reactor.

[0017] According to some embodiments of this application, an experimental system for studying the coupled combustion characteristics of coal and biomass is provided. The gas-solid separation module includes a cyclone separator and a fly ash collection tank. The inlet of the cyclone separator is connected to the exhaust port through the exhaust pipe. The solid phase outlet of the cyclone separator is connected to the fly ash collection tank through the solid phase discharge pipe. The gas phase outlet of the cyclone separator is connected to the flue gas dewatering module through the gas phase pipe.

[0018] An experimental system for studying the coupled combustion characteristics of coal and biomass according to some embodiments of this application includes a flue gas dewatering module comprising a drying tube and anhydrous calcium chloride. The inlet of the drying tube is connected to the gas phase outlet of the cyclone separator through the gas phase pipeline, and the outlet of the drying tube is connected to the flue gas analysis module through the flue gas pipeline. The anhydrous calcium chloride is disposed inside the drying tube.

[0019] An experimental system for studying the coupled combustion characteristics of coal and biomass, according to some embodiments of this application, includes a flue gas analysis module for real-time online analysis of CO2, O2, CO, SO2, and NO. x Concentration of gas components.

[0020] An experimental system for studying the coupled combustion characteristics of coal and biomass according to some embodiments of this application further includes a data analysis system. The data analysis system includes a data acquisition and control cabinet and a computer terminal. The data acquisition and control cabinet is connected to the multi-channel gas distribution module, the feeding module, the fluidized bed reactor, the heating module, the gas-solid separation module, the flue gas dewatering module, and the flue gas analysis module, respectively. The data acquisition and control cabinet is used to record and process flow data, temperature data, and component concentration data in real time. The computer terminal is used to generate corresponding characteristic curves.

[0021] In a second aspect, according to some embodiments of this application, an experimental method for studying the coupled combustion characteristics of coal and biomass, using the aforementioned experimental system, includes the following steps.

[0022] After mixing the coal and biomass, they are placed into the silo, and the upper and lower mixing mechanisms are turned on to mix the coal and biomass.

[0023] The flow rates of different gases are adjusted by a multi-channel gas distribution module and then mixed in a gas mixing chamber before being introduced into a fluidized bed reactor.

[0024] The heating module is activated to preheat the fluidized bed reactor to the set temperature.

[0025] Turn on the air compressor and screw feeder to continuously feed the mixed coal and biomass powder into the fluidized bed reactor through the feed pipeline for coupled combustion;

[0026] The flue gas generated by the reaction is separated from fly ash by a cyclone separator, dried by anhydrous calcium chloride, and finally enters the flue gas analysis module for gas composition and concentration analysis. The data analysis system records the parameters of the entire process and generates corresponding characteristic curves.

[0027] This invention discloses an experimental system and method for studying the coupled combustion characteristics of coal and biomass. It is equipped with an independent multi-channel gas distribution module and a gas mixing chamber, enabling precise control and thorough homogenization of each gas channel, eliminating gas concentration gradients, ensuring stable fluidization within the reactor, and meeting the needs for refined control of different combustion atmospheres. Simultaneously, the use of a sealed silo with pressure monitoring and anti-clogging structures, along with a screw feeder, adapts to the differences in physical properties between coal and biomass fuels, effectively preventing feeding bridging, jamming, and rate fluctuations, achieving continuous and stable quantitative fuel supply, and significantly improving the stability and repeatability of experimental conditions. By arranging thermocouples along the axial direction of the fluidized bed reactor, real-time monitoring of the spatial temperature gradient within the reactor can be achieved, accurately capturing combustion temperature characteristic parameters under different fuel ratios. A high-efficiency cyclone separator enables rapid gas-solid separation, accurately collecting fly ash samples for subsequent analysis, while reducing the load on downstream equipment. The flue gas undergoes deep dehydration via an anhydrous calcium chloride drying tube, completely avoiding interference and damage to the detection instruments from water vapor, ensuring the accuracy of flue gas detection. Furthermore, this invention can achieve simultaneous acquisition, cleaning, and analysis of multi-dimensional parameters such as flow rate, pressure, temperature field, and flue gas concentration, effectively solving problems such as unstable feeding, uneven atmosphere, partial temperature measurement, and asynchronous data in traditional platforms, and providing high-precision and high-stability experimental data support for the study and characteristic analysis of the coupled combustion mechanism of coal and biomass. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the structure of an experimental system for studying the coupled combustion characteristics of coal and biomass according to the present invention;

[0029] Figure 2 This is a graph showing the axial temperature distribution and continuous operation temperature stability of the fluidized bed reactor in Embodiment 2 of the present invention.

[0030] Figure 3 This is a schematic diagram of combustion efficiency and fly ash carbon content in Embodiment 2 of the present invention;

[0031] Figure 4 This is a line graph showing the pressure difference changes at different heights in the fluidized bed reactor in Embodiment 2 of the present invention;

[0032] Figure 5 This is a line graph showing the changes in flue gas composition during the continuous operation of the test system in Embodiment 2 of the present invention.

[0033] In the diagram: 1. Air compressor, 2. Ar gas cylinder, 3. O2 gas cylinder, 4. CO2 gas cylinder, 5. Gas mixing chamber, 6. Air flow meter, 7. Argon flow meter, 8. Oxygen flow meter, 9. Carbon dioxide flow meter, 10. Silo, 11. Pressure gauge, 12. Screw feeder, 13. Upper stirring mechanism, 14. Lower stirring mechanism, 15. Vibration assembly, 16. Fluidized bed reactor, 17. Air inlet, 18. Feed inlet, 19. Exhaust outlet, 20. Thermocouple, 21. Cyclone separator, 22. Fly ash collection tank, 23. Drying tube, 24. Anhydrous calcium chloride, 25. Flue gas analysis module, 26. Data acquisition and control cabinet, 27. Computer terminal, 28. Heating module. Detailed Implementation

[0034] The embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and should not be construed as limiting the scope of the invention.

[0035] Example 1: An experimental system for studying the coupled combustion characteristics of coal and biomass in this example, such as... Figure 1 As shown, the system includes a multi-channel gas distribution module, a feeding module, a fluidized bed reactor 16, a heating module 28, a gas-solid separation module, a flue gas dehydration module, and a flue gas analysis module 25. The multi-channel gas distribution module stores and provides the gases required for the experiment. The feeding module is connected to the multi-channel gas distribution module and stores and provides the coal and biomass required for the experiment. The multi-channel gas distribution module is connected to the bottom of the fluidized bed reactor 16, and the feeding module is connected to the side wall of the fluidized bed reactor 16. The fluidized bed reactor 16 provides the reaction site for the experiment. The heating module 28 is fitted on the radial outside of the fluidized bed reactor 16 and is used to heat the fluidized bed reactor 16. The gas-solid separation module is connected to the top of the fluidized bed reactor 16 and is used to separate the gas-solid mixture after the reaction. The flue gas dehydration module is connected to the gas-solid separation module and is used to remove moisture from the flue gas. The flue gas analysis module 25 is connected to the flue gas dehydration module and is used to analyze the composition and concentration of each component of the flue gas.

[0036] The multi-channel gas distribution module may include an air compressor 1, an Ar gas cylinder 2, an O2 gas cylinder 3, a CO2 gas cylinder 4, and a gas mixing chamber 5. The air compressor 1 is connected to the feeding module through a feed gas pipeline. The air compressor 1 is connected to the gas mixing chamber 5 through an air intake pipeline. The Ar gas cylinder 2 is connected to the gas mixing chamber 5 through an argon gas intake pipeline. The O2 gas cylinder 3 is connected to the gas mixing chamber 5 through an oxygen intake pipeline. The CO2 gas cylinder 4 is connected to the gas mixing chamber 5 through a carbon dioxide intake pipeline. The gas mixing chamber 5 is connected to the bottom of the fluidized bed reactor 16 through an intake pipeline. To achieve precise gas mixing ratios, such as simulating conventional air combustion with 21% O2 / 79% N2, or O2 / CO2 oxygen-enriched combustion atmospheres with different O2 concentrations, high-precision mass flow meters are connected in series on each independent gas source pipeline. The air inlet pipeline is equipped with an air flow meter 6, the argon inlet pipeline with an argon flow meter 7, the oxygen inlet pipeline with an oxygen flow meter 8, and the carbon dioxide inlet pipeline with a carbon dioxide flow meter 9. These are used to accurately set and provide real-time feedback on the mass flow rates of each individual gas component. After flow regulation, the four gas streams converge into a cylindrical gas mixing chamber with a specific physical volume. The gas mixing chamber 5 is designed to utilize gas turbulence diffusion and physical retention effects to completely eliminate concentration gradients and pressure fluctuations in the initial stage of gas merging. The homogeneous gas, after thorough mixing and buffering, is then stably introduced into the fluidized bed reactor as a fluidizing medium through the bottom inlet. In addition, while conventional methods use inert gases such as N2 for feeding and purging, this embodiment directly uses air for purging. Subsequently, the concentrations of various gases inside the fluidized bed reactor 16 are adjusted through Ar gas cylinder 2, O2 gas cylinder 3, CO2 gas cylinder 4 and gas mixing chamber 5, which can save experimental costs.

[0037] The feeding module includes a hopper 10, a pressure gauge 11, and a screw feeder 12. The hopper 10 is equipped with an upper stirring mechanism 13 and a lower stirring mechanism 14. The upper stirring mechanism 13 is used to continuously stir the coal and biomass to keep particles of different sizes and densities evenly distributed and avoid component stratification caused by long-term static storage. The lower stirring mechanism 14 is used to pre-loosen the coal and biomass in the feeding section to reduce the adhesion force and internal friction resistance between powders and improve the flow performance of the mixed fuel. In addition, the coal-spreading air sent into the hopper 10 through the feed air pipeline can effectively prevent the coal and biomass from sticking to the hopper 10. Through the dual-stage stirring and controllable coal-spreading air, the bridging effect and instantaneous agglomeration phenomenon that are prone to occur in the traditional single screw feeder process can be effectively improved. Compared to traditional single gravity feeding or ordinary screw conveying methods, this embodiment adopts a composite conveying path of "vertical stirring and homogenization - horizontal screw quantitative conveying," which ensures that the coal and biomass mixed fuel is fully depolymerized before entering the conveying section and maintains stable propulsion during the conveying process, reducing feeding fluctuations from the source. Pressure gauge 11 is installed at the top of the silo 10. The entire feeding system adopts a sealed connection structure and is equipped with a pressure monitoring device, achieving gas-solid isolation and real-time feedback of operating status during the feeding process, effectively preventing high-temperature flue gas backflow and powder leakage. The bottom outlet of the silo 10 is connected to the inlet of the screw feeder 12. A vibration component 15 is installed at the connection between the silo 10 and the screw feeder 12. The outlet of the screw feeder 12 is connected to the side wall of the fluidized bed reactor 16 through a downwardly inclined feed pipe. By incorporating a vibration assembly 15 and a downwardly inclined feed pipe, the vibration assembly 15 can periodically apply micro-amplitude mechanical disturbances, causing fuel particles adhering to the silo wall and the inner wall of the conveying channel to detach in a timely manner. Simultaneously, it disrupts the stable bridging structure formed inside the powder. The vibration assembly 15, in conjunction with the downwardly inclined feed pipe, ensures continuous, uniform, and blockage-free powder conveying. This achieves a transformation from traditional intermittent and unstable supply of coal and biomass blended fuel to a continuous, uniform, and intelligent supply method, providing reliable fuel transport guarantees for conducting fluidized bed combustion experiments under different blending ratios, different combustion atmospheres, and multi-parameter coupling conditions.

[0038] The fluidized bed reactor 16 is equipped with an air inlet 17, a feed inlet 18, an exhaust outlet 19, and a thermocouple 20. The air inlet 17 is located at the bottom of the fluidized bed reactor 16, and the gas mixing chamber 5 is connected to the air inlet 17 via an air inlet pipe. The feed inlet 18 is located on the side wall of the fluidized bed reactor 16, at a distance of one-sixth to one-fifth of the axial height of the fluidized bed reactor 16 from the air inlet 17. The inclined insertion structure design allows fuel to directly enter the dense phase region and the strong gas-solid disturbance region of the fluidized bed. With this arrangement, the coal and biomass particles entering the fluidized bed reactor 16 can be quickly subjected to the fluidizing medium and fully contact the high-temperature quartz sand bed material, achieving rapid heating, volatile matter release, and subsequent oxidation and combustion processes. At the same time, the inclined feed structure can effectively reduce the reverse migration of the bed material along the feed pipe under the action of airflow, improving the system's operational stability. The outlet of the screw feeder 12 is connected to the feed inlet 18 through the feed pipe. The exhaust port 19 is located at the top of the fluidized bed reactor 16 and is connected to the gas-solid separation module through the exhaust pipe. There are multiple thermocouples 20, which are arranged inside the side wall of the fluidized bed reactor 16 and along the axial height of the fluidized bed reactor 16.

[0039] In some embodiments, the fluidized bed reactor 16 is a cylindrical reactor operating at atmospheric / variable pressure. The fluidized bed reactor 16 is also equipped with a pressure monitoring module and a back pressure valve. By adjusting the back pressure valve, it can not only overcome the resistance of downstream components to maintain a stable atmospheric slightly positive pressure during routine tests, but also achieve step-wise or continuous adjustment of the system pressure in special pressurized combustion experiments. The main body of the fluidized bed reactor 16 is made of high-temperature resistant and corrosion-resistant stainless steel to meet the stringent requirements of high-temperature thermochemical reactions. A high-power electric heater is circumferentially wrapped around the outside of the fluidized bed reactor 16. This heating module 28 is controlled by a programmable PID temperature controller, which not only preheats the stainless steel bed to above the ignition temperature of the pulverized coal and biomass in the initial stage of the experiment, but also accurately compensates for the heat lost to the environment during the steady-state combustion stage, maintaining a constant and uniform furnace thermal environment.

[0040] The gas-solid separation module includes a cyclone separator 21 and a fly ash collection tank 22. The inlet of the cyclone separator 21 is connected to the exhaust port 19 via an exhaust pipe, the solid phase outlet of the cyclone separator 21 is connected to the fly ash collection tank 22 via a solid phase discharge pipe, and the gas phase outlet of the cyclone separator 21 is connected to the flue gas dewatering module via a gas phase pipe. The high-temperature flue gas discharged from the fluidized bed reactor 16 carries a large amount of fly ash and unburned carbon particles. The high-temperature flue gas rushes out at high speed from the exhaust port 19 at the top of the fluidized bed reactor 16 and then tangentially enters the cyclone separator 21. Under the strong centrifugal force of the cyclone separator 21, the denser solid particles are thrown against the wall and spiral down, eventually falling into the fly ash collection tank 22 at the bottom and being completely trapped. This gas-solid separation process not only provides high-purity solid-phase samples for subsequent research on the microstructure and mineral evolution of ash residue from coal and biomass coupled combustion, but also fundamentally blocks fine dust from entering the downstream gas phase pipeline, protecting the flue gas analysis module 25.

[0041] The flue gas dehydration module includes a drying tube 23 and anhydrous calcium chloride 24. The inlet of the drying tube 23 is connected to the gas phase outlet of the cyclone separator 21 through a gas phase pipeline, and the outlet of the drying tube 23 is connected to the flue gas analysis module 25 through a flue gas pipeline. The anhydrous calcium chloride 24 is located inside the drying tube 23.

[0042] The purified dry flue gas after deep dehydration is finally fed into the flue gas analysis module 25. Under normal pressure or pressure-swing coupling combustion test conditions of fuels such as coal / willow, the integrated flue gas analysis module 25 can comprehensively cover and simultaneously acquire conventional carbon / oxygen components such as CO2, O2, and CO, as well as nitrogen / sulfur pollutant components such as SO2, NO, N2O, and NO. x The system effectively reduces the gas dead volume and significantly shortens the instrument's response delay through a compact gas path optimization design. This not only ensures the accuracy of real-time sampling of multi-component gases but also guarantees the high-frequency fidelity of the dynamic evolution curves of various gas concentrations over time under complex testing conditions, providing reliable support for a comprehensive analysis of the element transformation and pollutant emission mechanisms in the coupled combustion process.

[0043] The experimental system also includes a data analysis system, comprising a data acquisition and control cabinet 26 and a computer terminal 27. The data acquisition and control cabinet 26 is connected to the multi-channel gas distribution module, feeding module, fluidized bed reactor 16, heating module 28, gas-solid separation module, flue gas dewatering module, and flue gas analysis module 25. The data acquisition and control cabinet 26 is used to record and process flow rate data, temperature data, and component concentration data in real time, while the computer terminal 27 is used to generate corresponding characteristic curves. The data analysis system ensures the traceability of parameters throughout the experiment and outputs high-dimensional and high-precision data.

[0044] This embodiment also provides an experimental method for studying the coupled combustion characteristics of coal and biomass. The experiment is conducted using the above-mentioned experimental system and includes the following steps:

[0045] After mixing the coal and biomass, the mixture is placed into the silo 10, and the upper stirring mechanism 13 and the lower stirring mechanism 14 are turned on to stir the coal and biomass.

[0046] The flow rates of different gases are adjusted by a multi-channel gas distribution module and mixed in the gas mixing chamber 5 before being introduced into the fluidized bed reactor 16.

[0047] Start the heating module 28 to preheat the fluidized bed reactor 16 to the set temperature;

[0048] Turn on the air compressor 1 and the screw feeder 12 to continuously feed the mixed coal and biomass powder into the fluidized bed reactor 16 through the feed pipeline for coupled combustion;

[0049] The flue gas generated by the reaction is separated from fly ash by cyclone separator 21, dried by anhydrous calcium chloride 24, and finally enters flue gas analysis module 25 for gas composition and concentration analysis. The data analysis system records the parameters of the whole process and generates corresponding characteristic curves.

[0050] Example 2: An experimental system for studying the coupled combustion characteristics of coal and biomass in this example. In order to realize the three-dimensional reconstruction of the thermodynamic state of the combustion space, five high-sensitivity thermocouples are scientifically arranged inside the fluidized bed reactor 16 along the upward axis of the airflow. The fluidized bed has a total height of 870 mm. The bottom thermocouples T1 and T2 extend into the dense phase zone, above the air distribution plate. Thermocouple T1 is 100 mm from the bottom flange, and thermocouple T2 is 200 mm from the bottom flange. These thermocouples monitor the bed temperature during the intense collision of fuel particles and the main combustion stage. The middle thermocouples T3 and T4 are located in the transition zone. Thermocouple T3 is 400 mm from the bottom flange, and thermocouple T4 is 500 mm from the bottom flange. These thermocouples primarily track the temperature rise during the large-scale release of volatiles and secondary combustion. The top thermocouple T5 is located in the free section, 700 mm from the bottom flange, and is used to monitor the final temperature before fly ash burnout and flue gas exiting the furnace. This multi-point temperature measurement matrix provides solid data support for analyzing the axial combustion dynamics of the fuel. In this embodiment, the feed inlet 18 is located approximately 60 mm above the air distribution plate.

[0051] In this embodiment, the biomass used is *Salix psammophila*, such as... Figure 2As shown, under the condition that the blending ratio of pure coal and sand willow is 10%~40%, the temperature at different heights of fluidized bed reactor 16 remains within the range of approximately 805~835℃. For the same fuel condition, the axial temperature difference of fluidized bed reactor 16 is small, and the temperature changes only slowly with the height of fluidized bed reactor 16, indicating good gas-solid contact and heat transfer within the bed, without obvious local low temperature zones or sudden temperature rises. As the blending ratio of sand willow increases, the overall temperature of fluidized bed reactor 16 rises, indicating that the addition of sand willow can promote fuel ignition and volatile matter release. During continuous operation for 120 minutes, the temperature at each measuring point fluctuates slightly around the corresponding average value, without continuous increase, continuous decrease, or large oscillation, indicating that the experimental system has good temperature control capability and thermal stability.

[0052] like Figure 3 As shown, under different coal types and sand willow blending ratios, the fuel combustion efficiency remained above 98.5%, reaching a maximum of approximately 99.04%. The corresponding fly ash carbon content ranged from approximately 8.17% to 12.36%. After adding an appropriate amount of sand willow, the combustion efficiency improved and the fly ash carbon content decreased under some operating conditions, indicating that coal and sand willow can achieve relatively complete combustion within the fluidized bed reactor 16. While the favorable blending ratios differed for different coal types, a high fuel burnout level was maintained under all experimental conditions, demonstrating that the device can adapt to different coal types and different coal-sand willow ratios.

[0053] like Figure 4 As shown, during continuous operation for 60 minutes, the pressure differential in the lower part of the fluidized bed reactor 16 fluctuated periodically around an average value of approximately 4 kPa, while the pressure differentials in the middle and upper parts remained within a relatively low and stable range. The high-frequency fluctuations in the pressure differential in the lower part of the fluidized bed reactor 16 were mainly caused by the movement of bed material particles, bubble generation and collapse, and gas-solid phase interaction, which are characteristic of dynamic fluctuations during normal operation of the fluidized bed. The average pressure differential values ​​in each section did not drift significantly with operating time, indicating that the bed material inventory and axial distribution were basically stable, and there was no obvious bed material accumulation, fluidization deterioration, or significant particle loss.

[0054] like Figure 5 As shown, during approximately 45 minutes of continuous combustion, the concentrations of CO, SO2, NO, and N2O fluctuated slightly around their respective average values, without any sustained increases, decreases, or sudden large changes. The stable changes in flue gas composition indicate that the fuel feed, fluidizing air supply, and in-bed combustion reaction maintained a dynamic balance, and the fuel release and oxidation processes exhibited good continuity.

[0055] The above-mentioned test results of temperature, combustion efficiency, bed pressure difference and flue gas composition show that the experimental system of this embodiment can maintain a stable temperature field, fluidization state and combustion process under continuous feeding conditions of coal and sand willow mixed fuel. It has good fuel adaptability to different coal types and different sand willow blending ratios and can achieve continuous and stable combustion of coal and biomass mixed fuel.

[0056] The embodiments of the present invention are given for illustrative and descriptive purposes only, and are not intended to be exhaustive or to limit the invention to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described in order to better illustrate the principles and practical application of the invention, and to enable those skilled in the art to understand the invention and to design various embodiments with various modifications suitable for a particular purpose.

Claims

1. An experimental system for studying the coupled combustion characteristics of coal and biomass, characterized in that, include A multi-channel gas distribution module, which is used to store and provide the gas required for the experiment; The feeding module is connected to the multi-channel gas distribution module and is used to store and provide the coal and biomass required for the experiment. A fluidized bed reactor (16) is provided with a multi-channel gas distribution module connected to the bottom of the fluidized bed reactor (16) and a feeding module connected to the side wall of the fluidized bed reactor (16). The fluidized bed reactor (16) is used to provide a reaction site for experiments. A heating module (28) is fitted on the radial outside of the fluidized bed reactor (16) and is used to heat the fluidized bed reactor (16). A gas-solid separation module is connected to the top of the fluidized bed reactor (16) and is used to separate the gas-solid mixture after the reaction. A flue gas water removal module is connected to the gas-solid separation module and is used to remove moisture from the flue gas. The flue gas analysis module (25) is connected to the flue gas dewatering module and is used to analyze the composition of the flue gas and the concentration of each component.

2. The experimental system for studying the coupled combustion characteristics of coal and biomass according to claim 1, characterized in that, The multi-channel gas distribution module includes an air compressor (1), an Ar gas cylinder (2), an O2 gas cylinder (3), a CO2 gas cylinder (4), and a gas mixing chamber (5). The air compressor (1) is connected to the feeding module through a feed gas pipeline. The air compressor (1) is connected to the gas mixing chamber (5) through an air intake pipeline. The Ar gas cylinder (2) is connected to the gas mixing chamber (5) through an argon gas intake pipeline. The O2 gas cylinder (3) is connected to the gas mixing chamber (5) through an oxygen intake pipeline. The CO2 gas cylinder (4) is connected to the gas mixing chamber (5) through a carbon dioxide intake pipeline. The gas mixing chamber (5) is connected to the bottom of the fluidized bed reactor (16) through an intake pipeline.

3. The experimental system for studying the coupled combustion characteristics of coal and biomass according to claim 2, characterized in that, The air intake pipe is equipped with an air flow meter (6), the argon intake pipe is equipped with an argon flow meter (7), the oxygen intake pipe is equipped with an oxygen flow meter (8), and the carbon dioxide intake pipe is equipped with a carbon dioxide flow meter (9).

4. The experimental system for studying the coupled combustion characteristics of coal and biomass according to claim 2, characterized in that, The feeding module includes a silo (10), a pressure gauge (11), and a screw feeder (12). The silo (10) is equipped with an upper stirring mechanism (13) and a lower stirring mechanism (14). The upper stirring mechanism (13) is used to continuously stir the coal and biomass, and the lower stirring mechanism (14) is used to pre-loosen the coal and biomass in the feeding section. The pressure gauge (11) is located at the top of the silo (10). The bottom outlet of the silo (10) is connected to the inlet of the screw feeder (12). A vibration component (15) is provided at the connection between the silo (10) and the screw feeder (12). The outlet of the screw feeder (12) is connected to the side wall of the fluidized bed reactor (16) through a downwardly inclined feed pipe.

5. The experimental system for studying the coupled combustion characteristics of coal and biomass according to claim 4, characterized in that, The fluidized bed reactor (16) is provided with an air inlet (17), a feed inlet (18), an exhaust outlet (19), and a thermocouple (20). The air inlet (17) is located at the bottom of the fluidized bed reactor (16). The gas mixing chamber (5) is connected to the air inlet (17) through the air inlet pipe. The feed inlet (18) is located on the side wall of the fluidized bed reactor (16) at a distance from the air inlet (17). At one-sixth to one-fifth of the axial height, the outlet of the screw feeder (12) is connected to the feed inlet (18) through the feed pipe. The exhaust port (19) is located at the top of the fluidized bed reactor (16) and is connected to the gas-solid separation module through the exhaust pipe. There are multiple thermocouples (20), which are arranged inside the side wall of the fluidized bed reactor (16) and along the axial height of the fluidized bed reactor (16).

6. The experimental system for studying the coupled combustion characteristics of coal and biomass according to claim 5, characterized in that, The gas-solid separation module includes a cyclone separator (21) and a fly ash collection tank (22). The inlet of the cyclone separator (21) is connected to the exhaust port (19) through the exhaust pipe. The solid phase outlet of the cyclone separator (21) is connected to the fly ash collection tank (22) through the solid phase discharge pipe. The gas phase outlet of the cyclone separator (21) is connected to the flue gas dewatering module through the gas phase pipe.

7. The experimental system for studying the coupled combustion characteristics of coal and biomass according to claim 6, characterized in that, The flue gas dewatering module includes a drying tube (23) and anhydrous calcium chloride (24). The inlet of the drying tube (23) is connected to the gas phase outlet of the cyclone separator (21) through the gas phase pipeline. The outlet of the drying tube (23) is connected to the flue gas analysis module (25) through the flue gas pipeline. The anhydrous calcium chloride (24) is disposed inside the drying tube (23).

8. The experimental system for studying the coupled combustion characteristics of coal and biomass according to claim 7, characterized in that, The flue gas analysis module (25) is used for real-time online analysis of CO2, O2, CO, SO2 and NO. x Concentration of gas components.

9. The experimental system for studying the coupled combustion characteristics of coal and biomass according to claim 8, characterized in that, It also includes a data analysis system, which includes a data acquisition control cabinet (26) and a computer terminal (27). The data acquisition control cabinet (26) is connected to the multi-channel gas distribution module, the feeding module, the fluidized bed reactor (16), the heating module (28), the gas-solid separation module, the flue gas dewatering module, and the flue gas analysis module (25), respectively. The data acquisition control cabinet (26) is used to record and process flow data, temperature data, and component concentration data in real time. The computer terminal (27) is used to generate corresponding characteristic curves.

10. An experimental method for studying the coupled combustion characteristics of coal and biomass, characterized in that, The experiment using the experimental system of claim 9 includes the following steps: After mixing the coal and biomass, put them into the silo (10), and turn on the upper stirring mechanism (13) and the lower stirring mechanism (14) to stir the coal and biomass; Different gas flow rates are adjusted by a multi-channel gas distribution module and mixed in a gas mixing chamber (5) before being introduced into a fluidized bed reactor (16). Start the heating module (28) to preheat the fluidized bed reactor (16) to the set temperature; Turn on the air compressor (1) and screw feeder (12) to continuously feed the mixed coal and biomass powder into the fluidized bed reactor (16) through the feed pipeline for coupled combustion; The flue gas generated by the reaction is separated from fly ash by a cyclone separator (21), dried by anhydrous calcium chloride (24), and finally enters the flue gas analysis module (25) for gas composition and concentration analysis. The data analysis system records the parameters of the whole process and generates corresponding characteristic curves.

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