Method and system for measuring and calculating thermal physical property coefficient of loose coal body in oxidation exothermic stage

Abstract

The application discloses a kind of loose coal body thermal property coefficient measurement method and system of exothermic oxidation stage, this measurement method experiment constructs temperature field, determines the loose coal body exothermic heat source term of coal body under high temperature oxidation (70 DEG C above) condition, when the boundary condition of measurement and calculation model function is consistent, the temperature rise curve of measuring point;Then construct thermal property parameter calculation model function and golden section search calculation model, measure the thermal diffusivity of loose coal body.The measurement method and system of the application are high in degree of automation, and the measurement result is reliable and stable, easy to operate;It comprehensively uses finite difference equation and golden section search algorithm, and introduces heat source term, eliminates the influence of self-heating of coal body in oxidation environment on thermal diffusivity test, improves the measurement accuracy and efficiency;Convenient for engineering application, the algorithm is packaged by program, and the calculation result can be obtained by inputting corresponding parameters.

Description

Technical Field

[0001] This invention relates to the field of thermophysical property testing, specifically to a method, system, and operating method for calculating the thermal diffusivity during the oxidative exothermic stage of loose coal. Background Technology

[0002] my country's resource endowment is characterized by "abundant coal, scarce oil, and limited gas," resulting in coal consistently accounting for over 50% of the country's primary energy consumption. Goaf areas after mining operations still contain geothermal resources generated from the oxidation and release of heat from residual coal, which have potential positive applications. Thermal properties are an important indicator for evaluating the efficiency of geothermal resource extraction; therefore, accurately measuring the thermal properties of loose coal seams is fundamental to research on geothermal energy extraction from goaf areas and is of great significance.

[0003] Currently, the main traditional approach to determining the thermal properties of loose coal is experimental measurement, which is theoretically divided into steady-state and unsteady-state methods. For example, the method and system for testing the thermal properties of loose coal disclosed in patent CN 101639455A uses a parallel hot-wire method. This method places a heating rod at the center of the coal sample as a heat source and records the heating power, time, and sample temperature for calculation. However, because the loose coal undergoes accelerated oxidation and exothermic processes during the test, the heat source itself interferes with the sample temperature data, leading to significant errors. To test the thermal conductivity of loose coal during the oxidation and exothermic process, a cooling method has been developed to determine the intensity of oxidation and thermal properties of each coal sample. For instance, patent CN101984349A discloses a method for testing the oxidation heat of loose coal, which calculates the thermal conductivity of the coal at different temperatures based on temperature, time, density, specific heat capacity, and porosity. This method requires many parameters, resulting in a long testing cycle.

[0004] Therefore, designing a method to rapidly measure the thermophysical parameters of loose coal during high-temperature oxidation and heat release is of great significance for the development and utilization of geothermal resources in goaf areas. Summary of the Invention

[0005] To address the aforementioned technical shortcomings, the purpose of this invention is to provide a system and method for calculating the thermal diffusivity of loose coal during the exothermic oxidation stage. By constructing a reasonable temperature field and combining the finite difference one-dimensional thermal conductivity equation under the first type of boundary conditions with the golden section search algorithm, the thermal diffusivity of loose coal can be quickly tested, and then thermal properties such as thermal conductivity and specific heat capacity can be calculated.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0007] A method for calculating the thermal diffusivity of loose coal during the exothermic oxidation stage includes the following steps:

[0008] S1: Experimentally determine the heat source term of loose coal body under high temperature oxidation conditions, and measure the temperature rise curve at the measuring point when the boundary conditions of the function in the calculation model are consistent.

[0009] S2: Construct the model function for calculating thermal property parameters, which is the finite difference one-dimensional heat conduction equation under the first kind of boundary conditions:

[0010]

[0011] The coal sample is divided into a grid along the axial direction, with each control volume having a length of Δx, and written in the form of a difference equation:

[0012]

[0013] For ease of calculation, it can be represented in matrix form:

[0014]

[0015] Its two boundary conditions are

[0016] T(b,t)=T(b)

[0017] T(c,t)=T(c)

[0018] Set the corresponding variable parameters, where: the superscript n represents the nth time step;

[0019] △t is the time step, in seconds;

[0020] △x is the distance between the control volume and the midpoint of its predecessor control volume, in cm;

[0021] T represents temperature, in °C;

[0022] α is the thermal diffusivity, in cm⁻¹ 2 / s;

[0023] A is the finite difference iteration coefficient matrix;

[0024] This is the interpolation matrix for the oxidation heat source function;

[0025] b and c are the positions of the two end boundaries, in cm;

[0026] S3: Fit the heat source term to the input, construct the coefficient matrix, form a convergent calculation equation, and solve to output the temperature of the temperature measurement point;

[0027] S4: Constructing the Golden Section Search Calculation Model:

[0028]

[0029]

[0030] Where, a low is the upper limit of the thermal diffusivity of the assumed loose coal mass, and a high is the lower limit of the thermal diffusivity of the assumed loose coal mass, is the golden ratio, taking

[0031] S5: Assume that at time t0, the temperature T(a, t0) at the measurement point calculated by substituting the assumed values of parameters a1 and a2 into the finite difference one-dimensional heat conduction equation; Substitute T(a, t0) and the measured true value T(t0) into the objective function S calculation model, and calculate the values S(a1) and S(a2) of the objective function calculation model corresponding to a1 and a2 respectively. The objective function S calculation model is:

[0032] S = [T(t0) - T(a, t0)] 2

[0033] S6: Reassign a low and a high Judge S(a1) and S(a2). When S(a1) > S(a2), let a low = a1; when S(a1) < S(a2), let a high = a2; Repeat the steps until |S(a1) - S(a2)| < 1×10 -6 Then stop the calculation, and record a ture = (a1 + a2) / 2 as the thermal diffusivity of the coal mass.

[0034] Preferably, fit the heat source interpolation method into a function interpolation matrix The input is the heat source term, substitute it into the heat source term of the calculation model function in step S2 to form a coefficient matrix; After testing the convergence of the equation, perform the calculation and solution of the equation to obtain the temperature at the measurement point position;

[0035] Another object of the present invention is to provide a system for measuring the thermal diffusivity of loose coal mass in the oxidation heat release stage, including a programmable temperature control box, a reaction kettle is installed in the programmable temperature control box, and the coal mass to be measured is installed in the reaction kettle; It also includes

[0036] A flipping heat source unit, the flipping heat source unit includes a rotatable heat preservation box wall and a reaction kettle upper cover, the rotatable heat preservation box wall is installed on the upper side wall of the programmable temperature control box and can rotate along the central axis of the temperature control box wall; The reaction kettle upper cover is installed on the rotatable heat preservation box wall, and the reaction kettle is connected to the rotatable heat preservation box wall by a spring top plate controlled by a servo motor;

[0037] A temperature control unit is installed on the outside of the reactor. It includes a heating wire installed in the programmable temperature control box and a heating element installed in the reactor cover. Both are controlled by a programmable temperature controller. It is a constant temperature heat source that can be controlled instantaneously. A heat dissipation device is installed at the bottom of the reactor to keep the overall temperature of the coal constant.

[0038] Temperature sensors are installed inside the cavity and top cover of the reactor.

[0039] A gas flow control unit, connected to the reactor, is used to provide a mixed gas at a set temperature.

[0040] The data processing unit includes a gas chromatograph and a computer, which are electrically connected to each other.

[0041] Preferably, the temperature control unit further includes a fan, which is installed on the inner wall of the programmable temperature control chamber, and the heating wire is installed between the fan and the reactor.

[0042] Preferably, the gas supply unit includes high-pressure gas cylinders and an inlet pipeline. The high-pressure gas cylinders are divided into three groups: oxygen, nitrogen, and air. Each high-pressure gas cylinder is equipped with a flow controller. Each high-pressure gas cylinder is connected to the beginning of the inlet pipeline. A gas preheating copper pipe is provided on the inlet pipeline. The end of the inlet pipeline is connected to the reaction vessel. The upper part of the reaction vessel is connected to the data processing unit through an outlet pipeline.

[0043] The flow controller includes a pressure reducing valve, a pressure regulating valve, a flow regulating valve, a pressure gauge, a gas resistance valve, and a flow sensor installed in sequence, and is used to control the proportion of each component in the mixed gas by adjusting the flow rates of oxygen, nitrogen, and air.

[0044] The third objective of this invention is to provide an operating method for a system for calculating the thermal diffusivity of loose coal during the exothermic oxidation stage, characterized by the following steps:

[0045] S1: Crush the fresh coal sample and screen two coal samples within the target particle size range. Load the first coal sample into the reaction vessel.

[0046] S2: Screw on the reactor lid, turn on the servo motor to control the reactor lid to rotate into the program temperature control box and fit against the reactor, set the gas supply unit to input nitrogen until the coal body is completely in a nitrogen environment, set the heating wire and heating element to the same ambient temperature preset value through the program temperature controller, and heat the program temperature control box.

[0047] S3: After the coal temperature stabilizes at the ambient temperature, a gas supply unit is set up to control the oxygen concentration ratio and input oxygen-containing mixed gas into the reactor. The computer records the temperature rise data.

[0048] S4: Set up the gas supply unit, input nitrogen into the reactor, and wait until the coal is completely in a nitrogen environment. Then close the gas cylinder, turn the reactor lid out of the box, take out the first coal sample, and replace it with the second coal sample.

[0049] S5: The heating element is controlled by the programmable temperature controller until the internal temperature of the reactor reaches the preset value of the ambient temperature. The heating element is then controlled to heat the reactor lid to the preset value of the reactor lid temperature. The reactor lid is rotated and the servo motor is turned on to make the reactor fit with the lid.

[0050] S6: Introduce an oxygen-containing mixed gas with the same oxygen concentration ratio as in step S3 into the reactor, and record the temperature rise curve by computer.

[0051] Preferably, the maximum particle size of the loose coal is 25 mm, and the amount of coal sample loaded into the reactor each time is 0.5 kg.

[0052] The beneficial effects of this invention are as follows:

[0053] 1. This experimental calculation system calculates the thermophysical parameters of loose coal under various environmental conditions by changing the proportion of gas components and the temperature of the programmed temperature control chamber, combined with gas chromatograph data, thereby improving the coupling degree with the goaf environment.

[0054] 2. The calculation method of this invention comprehensively utilizes the finite difference equation and the golden section search algorithm to solve the problem of inverse solution of second-order nonlinear partial differential equations. The allowable error and search range of its thermal diffusivity calculation can be freely set. This invention sets the absolute residual value between the model solution value and the experimental measured value to be less than 1e-3 and the number of iterations to be less than 20, thereby improving the accuracy and efficiency of the thermal diffusivity calculation of high-temperature loose coal.

[0055] 3. By substituting the heat source term obtained through experiments into the algorithm, the influence of the self-heating of the coal body in a high-temperature environment on the thermal diffusivity test is eliminated;

[0056] 4. This invention enables the placement of heat sources for instantaneous first-type boundary conditions of coal, so that the measurement experiment satisfies the boundary conditions of the one-dimensional thermal diffusion equation, and realizes the combination of finite difference method and experimental testing for calculation.

[0057] 5. It has a high degree of automation, reliable and stable measurement results, and is easy to operate; the algorithm is encapsulated in the program, and only the corresponding parameters need to be input to calculate the thermal diffusivity of loose coal under high temperature conditions. Attached Figure Description

[0058] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0059] Figure 1 This is a schematic diagram of the system for calculating the thermal diffusivity of loose coal during the oxidation exothermic stage provided in Embodiment 1 of the present invention.

[0060] Figure 2 This is a flowchart of the method for calculating the thermal diffusivity of loose coal in the oxidation exothermic stage provided in Embodiment 1 of the present invention.

[0061] Explanation of reference numerals in the attached figures:

[0062] 1. High-pressure gas cylinder; 2. Pressure reducing valve; 3. Pressure regulating valve; 4. Flow regulating valve; 5. Pressure gauge; 6. Gas resistance; 7. Flow sensor; 8. Insulation layer; 9. Gas preheating copper pipe; 10. Programmable temperature control chamber; 11. Gas inlet pipe; 12. Bottom of the reactor; 13. Reactor cavity; 14. Cavity temperature sensor; 15. Data line; 16. Gas outlet pipe; 17. Rotatable temperature control chamber wall; 18. Spring top plate; 19. Reactor top cover; 20. Heating wire; 21. Fan; 22. Programmable temperature controller; 23. Gas chromatograph; 24. Computer; 25. Top cover temperature sensor. Detailed Implementation

[0063] 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.

[0064] like Figure 1 As shown, a system for calculating the thermal diffusivity of loose coal during the oxidation exothermic stage includes a programmable temperature control chamber 10. The chamber 10 is composed of a stainless steel inner liner and an insulation layer 8, which is made of asbestos.

[0065] A reaction vessel is installed in the center of the programmable temperature control chamber 10. A variable power fan 21 is installed on the right side wall of the programmable temperature control chamber 10 to ensure uniform air temperature in the furnace. An electric heating wire 20 is installed between the fan 21 and the reaction vessel. The temperature of the electric heating wire 20 is controlled by a programmable temperature controller 22.

[0066] The reactor includes a lower reactor bottom 12, a reactor cavity 13, and a reactor top cover 19. A cavity temperature sensor 14 is installed inside the reactor cavity 13, with its other end electrically connected to a computer 24. The temperature sensor 14 uses a platinum resistance precision temperature sensing element, and the probe is positioned along the reactor's axis. The reactor is cylindrical, with the lower reactor bottom 12 at the bottom, which is a copper heat sink. The axial ends are made of copper, and the radial cylindrical body is constructed of multiple layers of insulation material: an inner layer of silicone, an outer layer of stainless steel, and a sandwich layer of nano-insulation material.

[0067] A gas flow controller controls the input of high-pressure gas cylinder 1 into the reactor through inlet pipe 11. Inlet pipe 11 is a thin steel pipe with a gas preheating copper pipe 9 installed on it. The gas preheating copper pipe 9 has a curved multi-row structure, which ensures that the mixed gas is fully preheated and that the gas temperature entering the coal tank reaches the set value. There are three sets of high-pressure gas cylinders 1, each connected to a gas flow controller, which can adjust the flow rates of oxygen, nitrogen, and air to obtain mixed gases with different oxygen concentrations. The mixed gas is input into the reactor through inlet pipe 11. The gas flow controller includes a pressure reducing valve 2, a pressure regulating valve 3, a flow regulating valve 4, a pressure gauge 5, a gas resistance valve 6, and a flow sensor 7, installed in sequence.

[0068] The inlet pipe 11 is connected to the inlet port at the bottom of the reactor, and the outlet pipe 16 is connected to the outlet port at the top of the reactor. The outlet pipe 16 is sequentially connected to a gas chromatograph 23 and a computer 24. Test data from the gas chromatograph 23 is transmitted to the computer 24 via a data cable. The gas chromatograph 23 can test the concentration of gas components produced by the oxidation of coal under heating, thus determining the degree of oxidation. It is also required to measure the thermal diffusivity at different degrees of oxidation.

[0069] The upper side wall of the temperature control chamber 10 is also provided with a flip-up heat source unit. The flip-up heat source unit includes a flip-up temperature control chamber wall 17, which can rotate along the central axis of the temperature control chamber wall. The heat source is an electric heating element controlled by the programmable temperature controller 22. A reactor cover 19 is installed on the flip-up temperature control chamber wall 17. The reactor cover 19 is connected to the chamber wall by a spring top plate 18 controlled by a servo motor. One end of the servo motor is fixed to the flip-up temperature control chamber wall 17 by screws, and the other end is connected to the spring top plate 18. The up and down movement of the reactor cover 19 can be controlled by controlling the spring top plate 18.

[0070] First, the heat source side of the upper cover is flipped out of the temperature control box. After the heat source temperature stabilizes at the set temperature, the temperature control box wall 17 is flipped over. Then, the servo motor is turned on to move the heat source of the upper cover downwards until it is in contact with the reactor. The spring top plate 18 can make the upper cover fit more tightly with the reactor. The servo motor is controlled by the electrical control cabinet, and the motor circuit and heat source circuit are built into the box wall. After flipping into the programmable temperature control box 10, the movement of the spring top plate is started according to the computer program language in the electrical control cabinet. The movement stops when the reactor upper cover 19 moves to contact the reactor cavity 13. The upper cover temperature sensor 25 is installed inside the reactor upper cover 19.

[0071] This invention incorporates two heat sources: a heat source at the bottom of the reactor lid to maintain the sample at the same temperature as the ambient environment, and a heat source at the top of the reactor lid to generate a temperature higher than the ambient environment. The flipping function prevents heat conduction from contact with the sample during heating. The flipping instantaneously provides the sample with a constant-temperature heat source.

[0072] The above-described apparatus was used to construct a temperature field. A constant-temperature heat source capable of instantaneous generation was placed at one end of the loose coal mass, while a radiator capable of rapid heat dissipation was placed at the other end, thus maintaining a constant temperature at the other end of the coal mass. The exothermic heat source term of the loose coal mass under high-temperature (above 70℃) oxidation conditions was measured, and the temperature rise data inside the reactor was recorded. The radiator was turned on when the programmed temperature control chamber was heated (at the start of the experiment) to reduce fluctuations in the ambient temperature around the reactor and maintain a constant ambient temperature for the sample and heat source during the experiment.

[0073] The specific calculation method is as follows: Figure 1 As shown, it includes the following steps:

[0074] S1: Crush the fresh coal sample and screen two coal samples with a particle size range of 0-0.1mm or other target particle size ranges. Load the first coal sample into the reactor. The maximum particle size of the loose coal is 25mm. The amount of coal sample loaded into the reactor each time is 0.5kg.

[0075] S2: Screw on the reactor lid, turn on the servo motor to control the reactor lid to rotate into the program temperature control box and fit it against the reactor, set the gas supply unit to input nitrogen gas until the coal body is completely in a nitrogen environment, set the heating wire and heating element to the same ambient temperature preset value of 70℃ through the program temperature controller, and heat the program temperature control box.

[0076] S3: After the coal temperature stabilizes at the ambient temperature, a gas supply unit is set up to control the oxygen concentration ratio and input oxygen-containing mixed gas into the reactor. The computer records the temperature rise data.

[0077] S4: Set up the gas supply unit, input nitrogen into the reactor, and wait until the coal body is completely in a nitrogen environment. Then, close the gas cylinder, turn the reactor lid out of the box, take out the first coal sample, cool it to the initial temperature, and replace it with the second coal sample. Since the system temperature is higher than the initial temperature due to the exothermic oxidation after the determination of the heat source of loose coal under oxidative conditions, and the sample has been oxidized and modified, it is necessary to cool it to the initial temperature and replace it with a new sample for thermal diffusivity testing.

[0078] S5: The heating element is controlled by the programmable temperature controller to heat the reactor until the internal temperature of the reactor reaches the preset value of 70°C. The heating element is then controlled to heat the reactor lid to the preset value of 100°C. The reactor lid is rotated and the servo motor is turned on to make the reactor fit with the lid.

[0079] S6: Introduce an oxygen-containing mixed gas with the same oxygen concentration ratio as in step S3 into the reactor, and record the temperature rise curve by computer.

[0080] Then, the thermal diffusivity of the loose coal mass is calculated using the algorithm proposed in this invention. A calculation model for thermal property parameters is constructed, which is a finite-difference one-dimensional heat conduction equation under the second and first type of boundary conditions:

[0081]

[0082] The coal sample is divided into a grid along the axial direction, with each control volume having a length of Δx, and written in the form of a difference equation:

[0083]

[0084] For ease of calculation, it can be represented in matrix form:

[0085]

[0086] Its two boundary conditions are

[0087] T(b,t)=T(b)

[0088] T(c,t)=T(c)

[0089] In the formula: the superscript n represents the nth time step;

[0090] △t is the time step, in seconds;

[0091] △x is the distance between the control volume and the midpoint of its predecessor control volume, in cm;

[0092] T represents temperature, in °C;

[0093] a is the thermal diffusivity, in cm⁻¹ 2 / s;

[0094] A is the finite difference iteration coefficient matrix;

[0095] is the interpolation matrix of the oxidation heat source function;

[0096] b and c are the positions of both ends, in cm;

[0097] The variables to be set in this step are: Δt is 0.01 s, Δx is 0.01 cm, and the initial value of a low is 0.0001 cm 2 / s, a high is 1 cm 2 / s, b is 0 cm, c is 10 cm;

[0098] Fit the heat source interpolation method to the function interpolation matrix The input is the heat source term, which is substituted into the heat source term of the corresponding calculation model function to form a coefficient matrix;

[0099] After testing the convergence of the equation, perform the calculation and solution of the equation to obtain the temperature at the measuring point position;

[0100] Assume that the upper and lower limits of the thermal diffusivity of the loose coal body are a low and a high , respectively, and construct the golden section search calculation model:

[0101]

[0102]

[0103] Among them, is the golden ratio, taking

[0104] Select the assumed time t0 = 300 s. Substitute the assumed values of a1 and a2 parameters into the temperature T(a, t0) at the measuring point calculated by the finite difference one-dimensional heat conduction equation; Substitute T(a, t0) and the measured true value T(t0) = 73.2 °C into the calculation model, and calculate the values S(a1) and S(a2) of the objective function calculation model corresponding to a1 and a2 respectively. The objective function calculation model S is:

[0105] S = [T(t0) - T(a, t0)] 2

[0106] Reassign a low and a high . Compare S(a1) and S(a2). When S(a1) > S(a2), let a low = a1; when S(a1) < S(a2), let a high = a2; Repeat the steps until |S(a1) - S(a2)| < 1×10 -6The calculation can only be stopped when the time is right, and 'a' is recorded. ture = (a1+a2) / 2; Repeat the selection of t0 several times and repeat the measurement for other temperature measurement points, recording a at this time. ture The mean value is 0.00312cm. 2 / s thermal diffusion system of coal body.

[0107] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A method for calculating the thermal diffusivity of loose coal during the exothermic oxidation stage, characterized in that, Includes the following steps: S1: Experimentally determine the heat source term of loose coal body under high temperature oxidation conditions, and measure the temperature rise curve at the measuring point when the boundary conditions of the function in the calculation model are consistent. S2: Construct the model function for calculating thermal property parameters, which is the finite difference one-dimensional heat conduction equation under the first kind of boundary conditions: ； The coal sample is divided into a grid along the axial direction, and written in the form of a difference equation: ； For ease of calculation, it can be represented in matrix form: ； Its two boundary conditions are ； ； Set the corresponding variable parameters, where: superscript Representing the One time step; Let be the time step, in seconds; The distance between the control body and the midpoint of its predecessor control body, in cm; T For temperature, ; Where is the thermal diffusivity, ; It is a finite difference iteration coefficient matrix; This is the interpolation matrix for the oxidation heat source function; b, c The two boundary positions, ; S3: Fit the heat source term to the input, construct the coefficient matrix, form a convergent calculation equation, and solve to output the temperature of the temperature measurement point; S4: Constructing the Golden Section Search Calculation Model: ； In the formula, Assuming an upper limit for the thermal diffusivity of loose coal, Assuming a lower limit for the thermal diffusivity of loose coal, Taking the golden ratio as an example, ; S5: Assumption At this time, the assumed value and The temperature at the measuring point is calculated by substituting the parameters into the finite difference one-dimensional heat conduction equation. ;Will and the true value measured in the experiment Substitute into the objective function The calculation model calculates separately. and The corresponding objective function calculates the value of the model. and objective function The calculation model is as follows: ； S6: Yes and Reassign value, check and ,when > season = ;when < season = Repeat the steps until... The calculation can only be stopped when the time is right, and the result should be recorded. is the thermal diffusivity of the coal.

2. The method for calculating the thermal diffusivity of loose coal in the exothermic oxidation stage according to claim 1, characterized in that, In step S3, the heat source interpolation method is fitted into a function interpolation matrix. The input is a heat source term, which is substituted into the heat source term of the calculation model function in step S2 to form a coefficient matrix; after the test equation converges, the equation is calculated and solved to obtain the temperature at the measuring point.

3. A measurement system applying the measurement method of claim 1, characterized in that, The system includes a programmable temperature control chamber, within which a reaction vessel is installed, and within the reaction vessel, the coal to be tested is installed; it also includes: The rotating heat source unit includes a rotating insulated box wall and a reactor top cover. The rotating insulated box wall is installed on the upper side wall of the programmable temperature control box and can rotate along the central axis of the temperature control box wall. The reactor top cover is installed on the rotating insulated box wall, and the reactor and the rotating insulated box wall are connected by a spring top plate controlled by a servo motor. A temperature control unit is installed on the outside of the reactor. It includes a heating wire installed in the programmable temperature control box and a heating element installed in the reactor cover. Both are controlled by a programmable temperature controller. It is a constant temperature heat source that can be controlled instantaneously. A heat dissipation device is installed at the bottom of the reactor to keep the overall temperature of the coal constant. Temperature sensors are installed inside the cavity and top cover of the reactor. A gas flow control unit, connected to the reactor, is used to provide a mixed gas at a set temperature. The data processing unit includes a gas chromatograph and a computer, which are electrically connected to each other.

4. The measurement system according to claim 3, characterized in that, The temperature control unit also includes a fan, which is installed on the inner wall of the programmable temperature control chamber, and the heating wire is installed between the fan and the reactor.

5. The measurement system according to claim 3, characterized in that, The gas supply unit includes high-pressure gas cylinders and an inlet pipeline. The high-pressure gas cylinders are available in three sets: oxygen, nitrogen, and air. Each high-pressure gas cylinder is equipped with a flow controller. All high-pressure gas cylinders are connected to the beginning of the inlet pipeline. A gas preheating copper pipe is installed on the inlet pipeline. The end of the inlet pipeline is connected to the reaction vessel. The upper part of the reaction vessel is connected to the data processing unit through an outlet pipeline. The flow controller includes a pressure reducing valve, a pressure regulating valve, a flow regulating valve, a pressure gauge, a gas resistance valve, and a flow sensor installed in sequence, and is used to control the proportion of each component in the mixed gas by adjusting the flow rates of oxygen, nitrogen, and air.

6. The method for operating the measurement system according to claim 5, characterized in that, The steps are as follows: S1: Crush the fresh coal sample and screen two coal samples within the target particle size range. Load the first coal sample into the reaction vessel. S2: Screw on the reactor lid, turn on the servo motor to control the reactor lid to rotate into the program temperature control box and fit against the reactor, set the gas supply unit to input nitrogen until the coal body is completely in a nitrogen environment, set the heating wire and heating element to the same ambient temperature preset value through the program temperature controller, and heat the program temperature control box. S3: After the coal temperature stabilizes at the ambient temperature, a gas supply unit is set up to control the oxygen concentration ratio and input oxygen-containing mixed gas into the reactor. The computer records the temperature rise data. S4: Set up the gas supply unit, input nitrogen into the reactor, and wait until the coal is completely in a nitrogen environment. Then close the gas cylinder, turn the reactor lid out of the box, take out the first coal sample, cool it to the initial temperature, and replace it with the second coal sample. S5: The heating element is controlled by the programmable temperature controller until the internal temperature of the reactor reaches the preset value of the ambient temperature. The heating element is then controlled to heat the reactor lid to the preset value of the reactor lid temperature. The reactor lid is rotated and the servo motor is turned on to make the reactor fit with the lid. S6: Introduce an oxygen-containing mixed gas with the same oxygen concentration ratio as in step S3 into the reactor, and record the temperature rise curve by computer.

7. The method for operating the measurement system according to claim 6, characterized in that, The maximum particle size of the loose coal is 25mm, and the amount of coal sample loaded into the reactor each time is 0.5kg.

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