A system and method for simultaneous measurement of parameters of combustion characteristics of a porous medium solid fuel

Abstract

The application provides a porous medium solid fuel combustion characteristic parameter synchronous measurement system and a measurement method. The measurement system comprises a combustion chamber, a sampling module, a flow control module and a data processing system. Through the cooperation of the above components, in-situ synchronous measurement of gas phase and solid phase temperature, combustion gas product component and concentration, real-time measurement of solid fuel mass loss and visual monitoring of the combustion process are realized, and the change law of the combustion characteristic parameters is fully mastered to facilitate accurate analysis of the combustion mechanism.

Description

Technical Field

[0001] This invention relates to the field of porous media solid fuel monitoring technology, specifically to a synchronous measurement system and method for porous media solid fuel combustion characteristic parameters. Background Technology

[0002] Porous media solid fuels play a crucial role in the global energy structure. Coal, as my country's primary energy source, occupies an important position in national economic development; biomass and porous carbon materials are key carriers in the clean energy transition. However, the combustion of porous media solid fuels can cause significant safety and environmental hazards. In particular, coalfield fires, as a major mining disaster worldwide, result in direct coal loss and large-scale resource waste; smoldering of humus and accumulated biomass can easily spread into open flames, causing large-scale fires that seriously threaten ecosystems and human safety. Therefore, clarifying the combustion mechanism of porous media solid fuels is crucial for balancing energy utilization efficiency and disaster risk prevention, and understanding the variation patterns of their combustion characteristic parameters is a prerequisite for analyzing the combustion mechanism.

[0003] Currently, combustion tests mostly employ self-constructed fuel combustion physics simulation experimental platforms, which mainly consist of four parts: a combustion furnace system, a heating system, a gas supply system, and a data acquisition system. Holes are drilled at fixed intervals on the same side of the furnace body, and measuring points T1 to T10 are arranged sequentially, with sensors inserted to measure solid temperatures. Furthermore, determining gas composition in combustion experiments is a core method for assessing combustion progress, reaction characteristics, and safety risks, providing crucial data support for theoretical research and practical prevention and control.

[0004] Another testing system mainly consists of a temperature acquisition subsystem and a gas acquisition subsystem, capable of acquiring data on different temperatures and indicator gases inside the coal sample throughout the entire smoldering process. The online gas monitor is used to collect and test key marker gases released during the smoldering process. The reactor top adopts an open design, with the instrument's metal sampling head positioned within the flue gas duct. High-temperature flue gas collected by the vacuum pump is processed by an electronic condenser before reaching the sensor surface, where it is quantitatively analyzed using electrochemical methods and finally exported as a digital signal.

[0005] In summary, existing testing methods are insufficient for in-situ simultaneous measurement of gas and solid phase temperatures, gaseous product composition and concentration, real-time monitoring of solid fuel mass loss, and visualization of the combustion process. Summary of the Invention

[0006] The purpose of this invention is to provide a synchronous measurement system and method for combustion characteristic parameters of porous media solid fuels, so as to solve the problems mentioned in the background art.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] This application provides a synchronous measurement system for combustion characteristic parameters of porous media solid fuels, including:

[0009] The combustion chamber is used to contain solid fuel samples;

[0010] The sampling module includes three rows of monitoring apertures arranged parallel to each other along the combustion chamber axis:

[0011] The first row of apertures is used to directly install solid temperature sensors; the second row of apertures is used to install gas temperature sensors, with a porous tube surrounding the gas temperature sensor; the third row of apertures is used to install gas sampling probes, with a porous tube surrounding the gas sampling probes; the porous tubes have a structure that blocks solid particles from passing through while allowing gas to pass freely.

[0012] The flow control module includes a suction line connected to the gas sampling probe, a miniature vacuum pump and a pressure sensor disposed on the line, and a controller electrically connected to them. The controller is configured to maintain a stable micro-negative pressure environment at the sampling point by adjusting the power of the vacuum pump.

[0013] The data processing system is used to synchronously collect temperature and gas concentration data. The system also includes a combustion state diagnosis module, which is configured to automatically identify and output combustion state information based on the spatiotemporal variation trends of the synchronously collected solid phase temperature, gas phase temperature, and gas concentration data.

[0014] Optional, also includes:

[0015] The mass measurement module includes a weighing balance located below the base support, on which the combustion chamber is placed for real-time monitoring of the mass change of the fuel sample.

[0016] The combustion state diagnostic module further receives mass loss data and uses it for combustion state identification.

[0017] Optional, also includes:

[0018] The visualization module includes at least two quartz glass observation windows located at different axial heights and connected to the side wall of the combustion chamber via flanges;

[0019] The data processing system is further configured to process image data acquired through the observation window to analyze the migration trajectory of the combustion front.

[0020] Optionally, the combustion state diagnostic module identifies the combustion state through at least one of the following logics:

[0021] Identifying smoldering-to-open-flame transition: When the difference between the solid phase temperature and the gas phase temperature at the same axial position continuously decreases to a set threshold, and at the same time a sharp decrease in CO concentration and a significant increase in CO2 concentration are detected, it is determined that a smoldering-to-open-flame transition has occurred.

[0022] Warning signs of impending flameout: When the rate of mass loss continues to decrease, and at the same time, the O2 concentration rises and the upward trend of the temperature at all measuring points stops or decreases, it is determined to be a sign of impending flameout.

[0023] Determining combustion completion: When the mass loss curve enters a stable plateau period and the temperature at all measuring points drops to near the ambient temperature, combustion is considered complete.

[0024] Optionally, the observation window of the visualization module is equipped with visible light and infrared thermal imaging equipment;

[0025] The data processing system is further configured to cross-validate and fuse the acquired infrared thermal imaging data with the readings of the gas temperature sensor to generate a two-dimensional temperature field distribution map inside the combustion chamber.

[0026] Optionally, a heating plate is provided at the bottom of the combustion chamber, and the combustion chamber is provided with an upper air port and a lower air port;

[0027] The system further includes an atmosphere control unit connected to the upper and lower air ports and configured to perform at least one of the following operations:

[0028] Simulate an underground fire environment: Close the upper air vent, and only the lower air vent provides low-flow-rate oxygen-deficient air;

[0029] Simulate combustion on the surface of stacked fuel: close the lower gas port, and provide ventilation only from the upper gas port;

[0030] Perform a variable oxygen concentration experiment: dynamically adjust the oxygen concentration of the introduced gas according to a preset program;

[0031] Global pressure management: By coordinating the intake air flow and exhaust air flow, the overall pressure of the combustion chamber is stabilized within a set range, providing a stable macroscopic pressure environment for local gas sampling.

[0032] Optionally, the combustion chamber is provided with a metal mesh, a heat insulation material, and a particulate filling layer from bottom to top;

[0033] The particulate filling layer is made of steel balls or glass beads.

[0034] Optionally, a sensor connector is provided at the monitoring hole array on the side wall of the combustion chamber for fixing and sealing the solid temperature sensor, gas temperature sensor and gas sampling probe.

[0035] Optionally, the bottom of the combustion chamber is provided with a threaded plate with a gas passage; the gas sampling probe is fixed to the threaded plate through a gas extraction pipe sealing joint, forming a bottom gas extraction path.

[0036] Secondly, this application provides a method for synchronously measuring the combustion characteristic parameters of porous media solid fuels using the system described above, comprising the following steps:

[0037] In the three rows of monitoring holes arranged axially in the combustion chamber, a solid temperature sensor, a gas temperature sensor with a porous tube sleeve, and a gas sampling probe with a porous tube sleeve are respectively installed.

[0038] The flow control module is activated to create and maintain a local micro-negative pressure environment at the gas sampling probe, simultaneously extracting undiluted in-situ reaction gas to the gas analyzer, and simultaneously recording data from the solid and gas temperature sensors.

[0039] The mass loss of the fuel sample is monitored and recorded in real time using a weighing balance located at the bottom of the combustion chamber.

[0040] The migration of the combustion front and changes in sample morphology are visualized and recorded through observation windows at different axial heights on the sidewall of the combustion chamber.

[0041] The data processing system synchronously collects temperature, gas concentration, mass data and visualization information, and the combustion status diagnosis module performs fusion analysis based on the spatiotemporal variation trends of the above multiple parameters, automatically identifying and outputting combustion status information.

[0042] The present invention adopts the above-described technical solution, and compared with the prior art, it has the following advantages:

[0043] This application provides a synchronous measurement system and method for combustion characteristic parameters of porous media solid fuel. The measurement system includes: a combustion chamber for containing solid fuel samples; a sampling module including three rows of monitoring holes arranged parallel to the axial direction of the combustion chamber, used to arrange a solid temperature sensor, a gas temperature sensor with porous tube protection, and a gas sampling probe with porous tube; a flow control module including a suction pipeline connected to the gas sampling probe, a miniature vacuum pump and a pressure sensor disposed on the pipeline, and a controller electrically connected to them, the controller being configured to maintain a stable micro-negative pressure environment at the sampling point by adjusting the power of the vacuum pump; and a data processing system for synchronously acquiring temperature and gas concentration data. The system also includes a combustion state diagnosis module, which is configured to automatically identify and output combustion state information based on the spatiotemporal variation trends of the synchronously acquired solid phase temperature, gas phase temperature, and gas concentration data. Through the coordinated operation of the above components, in-situ synchronous measurement of parameters such as gas phase and solid phase temperature, composition and concentration of combustion gas products, real-time measurement of solid fuel mass loss, and visual monitoring of the combustion process are achieved. This allows for a thorough understanding of the changing patterns of combustion characteristic parameters, facilitating accurate analysis of the combustion mechanism. Attached Figure Description

[0044] Figure 1 This is a schematic diagram of the experimental system of the present invention;

[0045] Figure 2 This is a top view of the experimental system of the present invention;

[0046] Figure 3 This is a schematic diagram of the distribution of the three rows of axial measuring points in this invention.

[0047] Figure label:

[0048] 1. Upper air inlet, 2. Flange, 3. Steel ball or glass bead, 4. Thermal insulation material, 5. Metal mesh, 6. Quartz glass window, 7. Sensor connector, 8-1 Gas temperature sensor, 8-2 Solid temperature sensor, 9. Threaded plate, 10. Air extraction pipe sealing joint, 11. Porous pipe, 12. Air extraction pipe, 13. Heating plate, 14. Lower air inlet, 15. Base bracket, 16. Weighing balance. Detailed Implementation

[0049] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0050] Furthermore, elements in this invention are referred to as being "fixed to" or "set on" another element, which may be directly on the other element or may also include an intervening element. When an element is considered to be "connected" to another element, it may be directly connected to the other element or may also include an intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementations.

[0051] The following detailed explanation of the proposed solution is illustrated with specific examples:

[0052] Please see Figures 1-3 This application provides a synchronous measurement system for combustion characteristic parameters of porous solid fuel, comprising: a combustion chamber for containing a solid fuel sample; and a sampling module including three rows of monitoring apertures arranged parallel to the axial direction of the combustion chamber. These three rows of apertures are spatially dedicated to: the first row for arranging a solid temperature sensor 8-2, whose probe end is in direct contact with the solid fuel to measure the skeletal temperature of the solid fuel; the second row for arranging a gas temperature sensor 8-1, which is fitted with a high-temperature resistant porous tube 11, suspending its probe end in the fuel pores to isolate contact interference from solid particles and accurately measure the true gas phase temperature within the pores; and the third row for arranging a gas sampling probe, which is fitted with a high-temperature resistant porous tube 11, allowing the probe inlet to be positioned... The gas is collected within the pores of the fuel, thus filtering solid particles to ensure that the collected gaseous products are in situ and undiluted by ambient air. The high-temperature resistant porous tube 11 has a structure that blocks solid particles from passing through while allowing gas to pass freely. The flow control module includes a suction pipe 12 connected to the gas sampling probe, a miniature vacuum pump and a pressure sensor installed on the pipe, and a controller electrically connected to them. The controller is configured to maintain a stable micro-negative pressure environment at the sampling point by adjusting the power of the vacuum pump. The data processing system is used to simultaneously collect temperature and gas concentration data. The system also includes a combustion state diagnosis module, which is configured to automatically identify and output combustion state information based on the spatiotemporal variation trends of the synchronously collected solid phase temperature, gas phase temperature, and gas concentration data.

[0053] In this embodiment, the flow control module is explained as follows:

[0054] The mechanism by which the controller adjusts the vacuum pump power: The controller adjusts the vacuum pump power through closed-loop feedback control (usually using a PID algorithm, i.e., proportional-integral-derivative control). The core logic is to compare the deviation between the actual gas pressure and the target slight negative pressure, and adjust the pumping intensity based on the deviation. The specific process is as follows:

[0055] Signal acquisition: The air pressure sensor monitors the local air pressure at the sampling point or in the air extraction pipeline in real time. Since the air extraction pipeline is connected to the sampling probe, the air pressure in the pipeline can reflect the air pressure status at the sampling point.

[0056] Deviation calculation: The controller compares the measured air pressure with the preset target slight negative pressure value, such as -5Pa to -20Pa, and sets it according to the sampling requirements to obtain the deviation value: ΔP = measured air pressure - target air pressure;

[0057] Power adjustment: The controller calculates the required power adjustment value based on the magnitude, accumulation, and rate of change of the deviation, and outputs an electrical signal to the vacuum pump drive circuit to change its input power.

[0058] If ΔP>0: that is, the measured air pressure is higher than the target value, that is, the sampling point has not reached the required slight negative pressure, indicating that the pumping intensity is insufficient. The controller increases the vacuum pump power to increase the pumping rate and reduce the air pressure at the sampling point to the target value.

[0059] If ΔP<0: The measured air pressure is lower than the target value, that is, the sampling point is under excessive negative pressure, indicating that the pumping intensity is too high. The controller reduces the vacuum pump power to reduce the pumping rate, so that the air pressure at the sampling point rises back to the target value.

[0060] Adjustment trigger scenarios: When the air pressure at the sampling point or pipeline deviates from the target value due to changes in the external environment or fluctuations in the system itself, the controller initiates adjustment; Environmental pressure changes: If the external air pressure rises, the air pressure at the sampling point will rise with the rise in external pressure. At this time, the vacuum pump power needs to be increased to maintain a slight negative pressure; Pipeline resistance changes: If the suction pipe is slightly blocked, the suction resistance increases, and the air pressure at the sampling point rises. The power needs to be increased to offset the resistance; Gas composition changes: If the gas density at the sampling point increases, the suction efficiency decreases. The power needs to be increased to maintain the suction rate; External interference: If the sampling probe moves or the surrounding airflow is disturbed, it will cause fluctuations in the air pressure at the sampling point. The controller will maintain stability by fine-tuning the power.

[0061] In this embodiment, as Figure 3 As shown: Three rows of equally spaced monitoring holes are opened along the axial direction on the sidewall of the combustion chamber, corresponding to the coal sample filling area of ​​the central combustion chamber. Two types of probes are inserted through the sensor connector 7: a gas temperature sensor 8-1 is directly inserted, ensuring that the end of the gas temperature sensor 8-1 is completely located at the central axis of the sample; a high-temperature resistant porous tube 11 is fitted over another set of solid temperature sensors 8-2, and then inserted through the sensor connector 7, so that the porous tube 11 is completely immersed in the pores of the coal sample, avoiding direct contact between coal sample particles and solid temperature sensors 8-2. During the experiment, the leads of both types of sensors are connected to an external temperature monitoring instrument, and data is collected synchronously every X seconds to record the changes in solid and gas phase temperatures at the axial center of different coal seams over time.

[0062] Furthermore, three rows of independent, equally spaced monitoring holes are axially arranged on the sidewall of the combustion chamber. These three rows are arranged in parallel in space and are dedicated to housing the solid temperature sensor 8-2, the gas temperature sensor 8-1, and the gas sampling probe, respectively. Both the gas temperature sensor 8-1 and the gas sampling probe are fitted with high-temperature resistant porous tubes 11. The sensor or probe is placed inside the porous tube 11, which acts as a protective sleeve inserted into the sample. The porous structure both blocks solid particles and allows gas to pass freely, ensuring that the measured gas temperature is the true temperature within the sample pores and that the collected gas components are the true components of the in-situ reaction products, avoiding gas mixing, dilution, and temperature distortion caused by open-space measurements.

[0063] In this embodiment, as Figure 1 As shown: A gas passage is opened on the threaded plate 9 at the center of the combustion chamber. After the extraction pipe 12 is fitted with a porous tube 11, it is fixed to the threaded plate 9 through the extraction pipe sealing joint 10, ensuring that the inlet end of the extraction pipe 12 is located in the pore area of ​​the sample fuel's central axis, corresponding to the temperature measurement point in space; the other end of the extraction pipe 12 is connected to an external gas analyzer. During the experiment, the reaction gas in the pores of the sample fuel is continuously extracted through the extraction pipe 12. After the gas passes through the porous tube 11 to filter solid particles, it enters the analyzer. The same time interval as the temperature acquisition is set, and the concentration data of components such as O2, CO, and CO2 are recorded synchronously.

[0064] In one specific embodiment, it further includes: a mass measurement module, including a weighing balance 16 disposed below the base support 15, the combustion chamber being placed on the weighing balance 16, for real-time monitoring of mass changes of the fuel sample; the combustion state diagnosis module further receives mass loss data and uses it for combustion state identification.

[0065] In this embodiment, before the experiment begins, the empty combustion chamber without sample fuel is placed on a weighing balance 16. The balance's built-in calibration function is used to zero the initial mass, eliminating the influence of the combustion chamber's own weight. After sample fuel is loaded into the central combustion chamber, the base support 15 supports the entire combustion chamber, which remains on the weighing balance 16. During the experiment, the balance collects real-time data on the total mass change of the combustion chamber and sample fuel, and the data is synchronously transmitted to an external data acquisition system via a data cable. The acquisition system automatically calculates the real-time mass loss of the sample fuel, which is then converted into a mass loss rate.

[0066] Furthermore, a load-bearing tray and a high-precision electronic analytical balance are added below the base support 15 to directly quantify the mass loss and consumption rate of the sample during combustion, realize the comprehensive correlation of multi-dimensional parameters, and fill the gap in traditional monitoring of mass quantification.

[0067] In one specific embodiment, it further includes: a visualization module, comprising at least two quartz glass observation windows located at different axial heights and connected to the sidewall of the combustion chamber via flange 2; the data processing system is further configured to: process image data acquired through the observation windows to analyze the migration trajectory of the combustion front.

[0068] In this embodiment, a circular or rectangular opening corresponding to the center of the combustion chamber is made on the non-monitoring side of the combustion chamber, and a quartz glass window 6 is embedded therein. The window frame is bolted to the side wall of the combustion chamber via a flange 2, and a high-temperature resistant sealing gasket is used to ensure the combustion chamber is sealed. Before the experiment, the sample fuel filling is observed through the quartz glass window 6 to ensure it meets the requirements. During the experiment, a high-definition camera is used to continuously photograph the phenomena inside the combustion chamber through the window.

[0069] Furthermore, a viewing window is added, through which the axial migration trajectory of the combustion front and the morphological changes of solid particles can be directly observed; the filling quality can also be directly checked to see if there are voids or uneven compaction, avoiding experimental errors caused by inconsistent sample conditions and improving data reliability.

[0070] In one specific embodiment, the combustion state diagnostic module identifies the combustion state through at least one of the following logics:

[0071] Identifying smoldering-to-open-flame transition: When the difference between the solid phase temperature and the gas phase temperature at the same axial position continuously decreases to a set threshold, and at the same time a sharp decrease in CO concentration and a significant increase in CO2 concentration are detected, it is determined that a smoldering-to-open-flame transition has occurred.

[0072] Warning signs of impending flameout: When the rate of mass loss continues to decrease, and at the same time, the O2 concentration rebounds and the upward trend of temperature at all measuring points stops or decreases, it is determined to be a sign of impending flameout.

[0073] Determining combustion completion: When the mass loss curve enters a stable plateau period and the temperature at all measuring points drops to near the ambient temperature, combustion is considered complete.

[0074] In this embodiment, the combustion state diagnosis module identifies the combustion state through at least one of the following logics: Identifying smoldering-to-open-flame transition: When the difference between the solid phase temperature and the gas phase temperature at the same axial position continuously decreases to a set threshold, for example, the temperature difference drops below 50°C, and simultaneously a sharp decrease in CO concentration is detected (e.g., a decrease exceeding 20%) and a significant increase in CO2 concentration (e.g., an increase exceeding 30%), a smoldering-to-open-flame transition is determined, and the consistency of frontal migration is verified by combining the image data from the observation window; Warning of pre-extinguishing signs: When the mass loss rate continuously decreases (e.g., the slope is less than 0.5 g / min), and simultaneously accompanied by an increase in O2 concentration (e.g., an increase exceeding 5%) and a stagnation or decrease in the temperature rise trend at all measuring points (e.g., the temperature change rate approaches zero), a pre-extinguishing sign is determined, and secondary confirmation is performed based on particle morphology changes fed back by the visualization module; Determining combustion completion: When the mass loss curve enters a stable plateau period (e.g., mass fluctuation less than 1% for more than 10 minutes), and the temperature at all measuring points drops to near ambient temperature (e.g., the temperature difference is within ±5°C), combustion is determined to be complete. In addition, the module also supports logical combination applications. For example, when identifying signs of transition or engine shutdown, it can automatically trigger the data processing system to record key parameters and output diagnostic reports in real time to improve experimental efficiency. At the same time, the threshold setting can be dynamically adjusted for different fuel characteristics to ensure the accuracy of identification.

[0075] In one specific embodiment, the observation window of the visualization module is equipped with visible light and infrared thermal imaging equipment; the data processing system is further configured to cross-validate and fuse the acquired infrared thermal imaging data with the readings of the gas temperature sensor 8-1 to generate a two-dimensional temperature field distribution map inside the combustion chamber.

[0076] In one specific embodiment, a heating plate 13 is provided at the bottom of the combustion chamber, and the combustion chamber is provided with an upper air port 1 and a lower air port 14; the system further includes an atmosphere control unit, which is connected to the upper air port 1 and the lower air port 14, and is configured to perform at least one of the following operations:

[0077] Simulated underground fire environment: The upper air inlet 1 is closed, and only the lower air inlet 14 provides low-flow oxygen-deficient air;

[0078] Simulated combustion of stacked fuel surface: the lower gas port 14 is closed, and ventilation is provided only by the upper gas port 1;

[0079] Perform a variable oxygen concentration experiment: dynamically adjust the oxygen concentration of the introduced gas according to a preset program;

[0080] Global pressure management: By coordinating the intake air flow and exhaust air flow, the overall pressure of the combustion chamber is stabilized within a set range, providing a stable macroscopic pressure environment for local gas sampling.

[0081] In this embodiment, the working principle of the atmosphere and pressure control unit in global pressure management can be achieved in the following way: for example, by linking the proportional valve installed on the exhaust pipe with the mass flow controller on the intake pipe, the central controller adjusts the valve opening in real time according to the feedback from the combustion chamber pressure sensor to ensure pressure stability.

[0082] In one specific embodiment, the combustion chamber is provided with a metal mesh 5, a heat insulation material 4 and a particulate filling layer from bottom to top;

[0083] The particulate filling layer is made of steel balls or glass beads 3. The function of the steel balls or glass beads is to ensure that the airflow reaches the combustion chamber evenly.

[0084] In one specific embodiment, a sensor connector 7 is provided at the monitoring hole array on the side wall of the combustion chamber for fixing and sealing the solid temperature sensor 8-2, the gas temperature sensor 8-1, and the gas sampling probe.

[0085] In one specific embodiment, a threaded plate 9 with a gas passage is provided at the bottom of the combustion chamber; the gas sampling probe is fixed to the threaded plate 9 through a gas extraction pipe sealing joint 10, forming a bottom gas extraction path.

[0086] Secondly, this application provides a method for synchronously measuring the combustion characteristic parameters of porous media solid fuels using the system described above, comprising the following steps:

[0087] In the three rows of monitoring holes arranged axially in the combustion chamber, a solid temperature sensor 8-2, a gas temperature sensor 8-1 with a porous tube 11 sleeve, and a gas sampling probe with a porous tube 11 sleeve are respectively installed.

[0088] The flow control module is activated to create and maintain a local micro-negative pressure environment at the gas sampling probe, simultaneously extracting undiluted in-situ reaction gas to the gas analyzer, and simultaneously recording the data from the solid and gas temperature sensors 8-1.

[0089] The mass loss of the fuel sample is monitored and recorded in real time using a weighing balance 16 located at the bottom of the combustion chamber.

[0090] The migration of the combustion front and changes in sample morphology are visualized and recorded through observation windows at different axial heights on the sidewall of the combustion chamber.

[0091] The data processing system synchronously collects temperature, gas concentration, mass data and visualization information, and the combustion status diagnosis module performs fusion analysis based on the spatiotemporal variation trends of the above multiple parameters, automatically identifying and outputting combustion status information.

[0092] Experimental example:

[0093] 1. Experimental Objective

[0094] The invention verifies the system's ability to simultaneously measure solid / gas phase temperature, gaseous product concentration, mass loss, and visualize combustion front migration during the smoldering process of lignite, and demonstrates its intelligent combustion state diagnostic function.

[0095] 2. Experimental Materials and System Configuration

[0096] Sample: Lignite crushed to 3-5mm, initial mass 500g, initial moisture content 15%.

[0097] System: The system claimed in claims 1-7.

[0098] Atmosphere control: The "simulated underground fire environment" mode is adopted, and only the lower air port 14 provides oxygen-deficient air with an oxygen content of 10% at a flow rate of 0.5L / min.

[0099] Heating: The bottom of the sample is heated to 300°C at the beginning of the experiment by the bottom heating plate 13 to ignite it.

[0100] Data acquisition: All sensors collect data synchronously every 10 seconds.

[0101] 3. Experimental Procedure and Results

[0102] 3.1 Simultaneous Visualization and Observation of Temperature Field and Combustion Front Migration

[0103] Table 1: Axial temperature distribution and front location

[0104]

[0105] 3.2 In-situ synchronous measurement of gas-solid phase temperature and gas composition

[0106] Table 2: Synchronous Data Record of Key Parameters at Central Measurement Points

[0107]

[0108] 3.3 Real-time monitoring of mass loss

[0109] Table 3: Quality Loss Data

[0110]

[0111] 4. Demonstration of intelligent combustion status diagnosis

[0112] The most outstanding effect of this experiment is that the system successfully issued an early warning of "signs of impending engine shutdown".

[0113] Time point: around 115 minutes.

[0114] Diagnostic basis:

[0115] The rate of mass loss continued to decrease: from 0.98 g / min at 100 minutes to 0.21 g / min at 115 minutes.

[0116] O2 concentration rebounds: Due to the weakening of the combustion reaction and the reduction in oxygen consumption, the O2 concentration rebounded from a low of 7.0% to 8.8%.

[0117] The upward trend in temperature has stalled: the temperature at all measuring points has stopped rising and has begun to fall.

[0118] The system automatically outputs: At 117 minutes, the combustion status diagnosis module of the data processing system pops up a warning on the user interface: "Alarm: Pre-extinguishing signs detected."

[0119] 5. Experimental Conclusions

[0120] The experimental examples and simulation data fully demonstrate the superior performance of the system of this invention:

[0121] Synchronization: Successfully achieved in-situ, synchronous, and spatiotemporally correlated measurement of solid phase temperature, gas phase temperature, gas component concentration, mass loss, and visualization information.

[0122] Accuracy: Based on the "micro-negative pressure sampling" and "porous tube 11 protection" technologies, undisturbed real in-situ data were obtained, revealing key phenomena such as gas-solid phase temperature difference.

[0123] Intelligence: Through multi-parameter data fusion, the system has advanced functions for intelligent diagnosis of combustion status, such as the "flameout precursor" warning demonstrated in this experiment, which is of great value for laboratory safety and fire prevention research.

[0124] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0125] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A synchronous measurement system for combustion characteristic parameters of porous media solid fuels, characterized in that, include: The combustion chamber is used to contain solid fuel samples; The sampling module includes three rows of monitoring apertures arranged parallel to each other along the combustion chamber axis: The first row of holes is used to directly install solid temperature sensors (8-2); the second row of holes is used to install gas temperature sensors (8-1), with a porous tube (11) covering the gas temperature sensor (8-1); the third row of holes is used to install gas sampling probes, with a porous tube (11) covering the gas sampling probes; wherein, the structure of the porous tube (11) can block solid particles from passing through while allowing gas to pass through freely; The flow control module includes a suction line connected to the gas sampling probe, a miniature vacuum pump and a pressure sensor disposed on the line, and a controller electrically connected to them. The controller is configured to maintain a stable micro-negative pressure environment at the sampling point by adjusting the power of the vacuum pump. The data processing system is used to synchronously collect temperature and gas concentration data. The system also includes a combustion state diagnosis module, which is configured to automatically identify and output combustion state information based on the spatiotemporal variation trends of the synchronously collected solid phase temperature, gas phase temperature, and gas concentration data. Also includes: The mass measurement module includes a weighing balance (16) located below the base support (15), on which the combustion chamber is placed for real-time monitoring of the mass change of the fuel sample; The combustion state diagnosis module further receives mass loss data and uses it for combustion state identification; Also includes: The visualization module includes at least two quartz glass observation windows located at different axial heights and connected to the sidewall of the combustion chamber via flanges (2); The data processing system is further configured to process image data acquired through the observation window to analyze the migration trajectory of the combustion front; The combustion status diagnosis module identifies the combustion status through at least one of the following logics: Identifying smoldering-to-open-flame transition: When the difference between the solid phase temperature and the gas phase temperature at the same axial position continuously decreases to a set threshold, and at the same time a sharp decrease in CO concentration and a significant increase in CO2 concentration are detected, it is determined that a smoldering-to-open-flame transition has occurred. Warning signs of impending flameout: When the rate of mass loss continues to decrease, and at the same time, the O2 concentration rises and the upward trend of the temperature at all measuring points stops or decreases, it is determined to be a sign of impending flameout. Determining combustion completion: When the mass loss curve enters a stable plateau period and the temperature at all measuring points drops to near the ambient temperature, combustion is considered complete.

2. The system according to claim 1, characterized in that, The observation window of the visualization module is equipped with visible light and infrared thermal imaging equipment. The data processing system is further configured to cross-validate and fuse the acquired infrared thermal imaging data with the readings of the gas temperature sensor (8-1) to generate a two-dimensional temperature field distribution map inside the combustion chamber.

3. The system according to claim 1, characterized in that, The bottom of the combustion chamber is provided with a heating plate (13), and the combustion chamber is provided with an upper air port (1) and a lower air port (14); The system further includes an atmosphere control unit connected to the upper air port (1) and the lower air port (14), and configured to perform at least one of the following operations: Simulated underground fire environment: The upper air inlet (1) is closed, and only the lower air inlet (14) provides low-flow oxygen-deficient air; Simulated combustion on the surface of stacked fuel: the lower gas port (14) is closed, and ventilation is provided only by the upper gas port (1); Perform a variable oxygen concentration experiment: dynamically adjust the oxygen concentration of the introduced gas according to a preset program; Global pressure management: By coordinating the intake air flow and exhaust air flow, the overall pressure of the combustion chamber is stabilized within a set range, providing a stable macroscopic pressure environment for local gas sampling.

4. The system according to claim 1, characterized in that, The combustion chamber is provided with a metal mesh (5), a heat insulation material (4) and a particulate filling layer from bottom to top; The material of the particulate filling layer is steel balls or glass beads (3).

5. The system according to claim 1, characterized in that, A sensor connector (7) is provided at the monitoring hole array on the side wall of the combustion chamber for fixing and sealing the solid temperature sensor (8-2), the gas temperature sensor (8-1) and the gas sampling probe.

6. The system according to claim 1, characterized in that, The bottom of the combustion chamber is provided with a threaded plate (9) with a gas passage; the gas sampling probe is fixed to the threaded plate (9) through the gas extraction pipe sealing joint (10) to form a bottom gas extraction path.

7. A method for synchronously measuring combustion characteristic parameters of porous media solid fuels using the system described in any one of claims 1-6, characterized in that, Includes the following steps: In the three rows of monitoring holes arranged axially in the combustion chamber, a solid temperature sensor (8-2), a gas temperature sensor (8-1) with a porous tube (11) sleeve, and a gas sampling probe with a porous tube (11) sleeve are respectively installed. The flow control module is activated to create and maintain a local micro-negative pressure environment at the gas sampling probe, and simultaneously extracts undiluted in-situ reaction gas to the gas analyzer, while simultaneously recording the data from the solid and gas temperature sensors (8-1). The mass loss of the fuel sample is monitored and recorded in real time by a weighing balance (16) located at the bottom of the combustion chamber; The migration of the combustion front and changes in sample morphology are visualized and recorded through observation windows at different axial heights on the sidewall of the combustion chamber. The data processing system synchronously collects temperature, gas concentration, mass data and visualization information, and the combustion status diagnosis module performs fusion analysis based on the spatiotemporal variation trends of the above multiple parameters, automatically identifying and outputting combustion status information.

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