阅读说明：本技术 一种利用微波加热的煤自燃程序控温系统及方法 (Coal spontaneous combustion program temperature control system and method using microwave heating ) 是由 肖旸 石群 高鲁晗 王亚超 尹岚 李青蔚 芦星 王凯 于 2021-03-09 设计创作，主要内容包括：本发明公开了一种利用微波加热的煤自燃程序控温系统及方法,其中,所涉及的煤自燃程序控温系统,包括加热机构、煤样承载机构、电控机构和气体采集分析机构；加热机构利用微波发生器对煤样承载机构中的煤样加热；电控机构用于控制煤样的加热功率及通向煤样的气体流量；气体采集分析机构用于采集分析过程中产生的气样。本发明还涉及利用微波加热的煤自燃程序控温方法,包括煤样填充、程序升温、控温模式等阶段,其中,综合考虑微波加热实际效果与工业中的能耗比,在程序升温阶段设定微波的频率值为2.45GHz,加热功率值为1.2～1.6kw。本发明适于在对煤自燃特性研究时使用,可保证煤样快速、均匀的升温,并实现升温速率的可控,能满足不同实验需求。(The invention discloses a coal spontaneous combustion program temperature control system and a method using microwave heating, wherein the coal spontaneous combustion program temperature control system comprises a heating mechanism, a coal sample bearing mechanism, an electric control mechanism and a gas acquisition and analysis mechanism; the heating mechanism heats the coal sample in the coal sample bearing mechanism by using the microwave generator; the electric control mechanism is used for controlling the heating power of the coal sample and the gas flow leading to the coal sample; the gas collection and analysis mechanism is used for collecting gas samples generated in the analysis process. The invention also relates to a coal spontaneous combustion program temperature control method by utilizing microwave heating, which comprises the stages of coal sample filling, program temperature rising, temperature control modes and the like, wherein the frequency value of the microwave is set to be 2.45GHz and the heating power value is 1.2-1.6 kw in the program temperature rising stage by comprehensively considering the actual microwave heating effect and the energy consumption ratio in the industry. The device is suitable for being used in the research of the spontaneous combustion characteristic of coal, can ensure the rapid and uniform temperature rise of the coal sample, realizes the controllability of the temperature rise rate, and can meet different experimental requirements.)

1. A coal spontaneous combustion program temperature control system using microwave heating is characterized in that: comprises a heating mechanism, a coal sample bearing mechanism, an electric control mechanism and a gas collecting and analyzing mechanism; the heating mechanism comprises a microwave generator, a microwave energy applicator and a microwave transmitter which is used for connecting the microwave generator and the microwave energy applicator and realizing microwave conduction, wherein the coal sample bearing mechanism is arranged in the microwave energy applicator;

the electric control mechanism comprises a temperature control module and a gas flow control module; the temperature control module comprises a temperature controller and a temperature sensor arranged in the coal sample bearing mechanism; the gas flow control module comprises a gas cylinder communicated with the bottom of the coal sample bearing mechanism, a pressure controller arranged in the gas cylinder and a flow controller arranged on the connecting pipeline;

the gas collecting and analyzing mechanism comprises a gas chromatograph communicated with the top of the coal sample bearing mechanism.

2. The coal spontaneous combustion program temperature control system using microwave heating according to claim 1, characterized in that: the microwave energy applicator is a resonant cavity made of non-ferromagnetic material; a box door is arranged on the resonant cavity, and a heat-insulating coating is coated in the cavity.

3. The coal spontaneous combustion program temperature control system using microwave heating according to claim 2, characterized in that: the microwave generator comprises a magnetron and a transformer which are arranged in a microwave electric appliance control box; the transformer is electrically connected with the temperature controller; and a heat radiation fan for cooling the device is also arranged in the microwave electrical appliance control box.

4. The coal spontaneous combustion program temperature control system using microwave heating according to any one of claims 1 to 3, characterized in that: the temperature controller includes a speed motor and a power conditioner motor connected to a computer.

5. The coal spontaneous combustion program temperature control system using microwave heating according to claim 4, characterized in that: and a pipeline for communicating the gas chromatograph with the coal sample bearing mechanism is also provided with an electromagnetic valve for controlling the on-off of gas.

6. The coal spontaneous combustion program temperature control system using microwave heating according to any one of claims 1 to 3 and 5, characterized in that: the coal sample bearing mechanism comprises a coal sample tank arranged in the microwave energy applicator through a coal sample tank tray; the coal sample tank is characterized in that a coal sample bracket is arranged at the bottom of the coal sample tank, a detachable end cover is arranged at the top of the coal sample tank, and a temperature sensor sleeve penetrating into the coal sample tank is fixedly arranged on the end cover.

7. The coal spontaneous combustion program temperature control system using microwave heating according to claim 6, characterized in that: the coal sample bracket is a through hole clapboard covered with asbestos cloth.

8. The coal spontaneous combustion program temperature control system using microwave heating according to claim 6, characterized in that: the coal sample jar is the tubular structure by ceramic material preparation, and the diameter is 30 ~ 50 mm.

9. The coal spontaneous combustion program temperature control system using microwave heating according to claim 7 or 8, characterized in that: the top of the coal sample tank is also communicated with the water tank.

10. A coal spontaneous combustion program temperature control method by utilizing microwave heating is characterized in that: a microwave-heated coal auto-ignition programmed temperature control system as claimed in any one of claims 1 to 9, comprising the following steps performed sequentially in order:

s1, filling a coal sample: after the coal sample is filled in the coal sample bearing mechanism, the temperature sensor is inserted, and the real-time communication between the electric control mechanism and the gas chromatograph and the computer is ensured;

s2, temperature programming: introducing gas into the coal sample bearing mechanism, and controlling the gas flow through a computer; then heating and heating the coal sample carrying mechanism by using a microwave generator, and setting the frequency value of the microwave to be 2.45GHz and the heating power value to be 1.2-1.6 kw through a computer; meanwhile, the heating time of 3-5 s is ensured;

s3, temperature control mode: and (3) closing the microwave generator, stopping heating, monitoring the temperature of the coal sample through a temperature sensor, extracting gas samples once every 10-15 ℃, analyzing the gas by using a gas chromatograph, and transmitting data results to a computer.

Technical Field

The invention belongs to the technical field of coal spontaneous combustion characteristic research, and particularly relates to a coal spontaneous combustion program temperature control system and method utilizing microwave heating.

Background

Coal spontaneous combustion is one of the hazards affecting mine safety, and not only can release toxic and harmful gases to cause atmospheric pollution, but also can cause gas explosion to damage the safety and health of mine workers and coal resources and production equipment, thereby causing huge economic loss. The spontaneous combustion of coal is a self-accelerating coal-oxygen composite heat release process, oxygen molecules firstly form physical and chemical adsorption heat on the surface of coal, so that the temperature of a coal body is increased, further, the oxygen molecules and active functional groups on the surface of the coal molecules are promoted to generate oxidative decomposition reaction, a large amount of reaction heat is released, and the heat is accumulated in the coal body, so that the spontaneous combustion of the coal is finally caused. The exothermic characteristics of the coal-oxygen recombination process are influenced by various factors, such as temperature, the deterioration degree of the coal body, the surface area of the coal body in contact with air, and the like, so that the spontaneous combustion period and the index gas of the coal must be determined through experimental study.

The program temperature control device is a commonly used experimental device for researching the spontaneous combustion and ignition period of coal and index gas. The heating mode of the existing program temperature control device is generally that a heating pipe heats a coal sample or high-temperature methyl silicone oil and edible oil are used, the temperature of the coal sample in a coal sample tank is raised from the outside to the inside by utilizing heat transfer, and gas is collected at a specific temperature. However, the above method for heating the coal sample requires a long time to reach the set temperature, and generally has the problems that the temperature distribution of the coal sample in the coal sample tank is not uniform, and the temperature rise rate is difficult to control.

Disclosure of Invention

In order to overcome the defects in the prior art, the invention aims to provide a coal spontaneous combustion program temperature control system and method utilizing microwave heating, so that the coal sample can be efficiently, quickly and uniformly heated, and the purpose of controlling the heating rate is realized.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows: a coal spontaneous combustion program temperature control system heated by microwave comprises a heating mechanism, a coal sample bearing mechanism, an electric control mechanism and a gas collecting and analyzing mechanism; the heating mechanism comprises a microwave generator, a microwave energy applicator and a microwave transmitter which is used for connecting the microwave generator and the microwave energy applicator and realizing microwave conduction, wherein the coal sample bearing mechanism is arranged in the microwave energy applicator;

the electric control mechanism comprises a temperature control module and a gas flow control module; the temperature control module comprises a temperature controller and a temperature sensor arranged in the coal sample bearing mechanism; the gas flow control module comprises a gas cylinder communicated with the bottom of the coal sample bearing mechanism, a pressure controller arranged in the gas cylinder and a flow controller arranged on the connecting pipeline;

the gas collecting and analyzing mechanism comprises a gas chromatograph communicated with the top of the coal sample bearing mechanism.

As a limitation of the invention, the microwave energy applicator is a resonant cavity made of a non-ferromagnetic material; a box door is arranged on the resonant cavity, and a heat-insulating coating is coated in the cavity.

As a further limitation of the present invention, the microwave generator comprises a magnetron and a transformer provided in a control box of the microwave appliance; the transformer is electrically connected with the temperature controller; and a heat radiation fan for cooling the device is also arranged in the microwave electrical appliance control box.

As another limitation of the invention, the temperature controller includes a speed motor and a power conditioner motor connected to the computer.

As a further limitation of the invention, a pipeline for communicating the gas chromatograph and the coal sample bearing mechanism is also provided with an electromagnetic valve for controlling the on-off of the gas.

As a third limitation of the present invention, the coal sample carrying mechanism comprises a coal sample tank disposed inside the microwave energy applicator via a coal sample tank tray; the coal sample tank is characterized in that a coal sample bracket is arranged at the bottom of the coal sample tank, a detachable end cover is arranged at the top of the coal sample tank, and a temperature sensor sleeve penetrating into the coal sample tank is fixedly arranged on the end cover.

As a further limitation of the invention, the coal sample bracket is a through hole partition plate covered with asbestos cloth.

As a further limitation of the invention, the coal sample tank is a cylindrical structure made of ceramic materials, and the diameter of the coal sample tank is 30-50 mm.

As a still further limitation of the present invention, the top of the coal sample tank is also in communication with a water tank.

Due to the adoption of the technical scheme, compared with the prior art, the invention has the following beneficial effects:

(1) according to the invention, a microwave heating mode is adopted, when a coal sample is heated, polar molecules in the coal are deflected under the influence of an external alternating electromagnetic field, and then the internal vibration generates heat, compared with the traditional mode of heating the coal sample by using a heating rod, the system realizes quick temperature rise of the coal sample, and simultaneously correspondingly improves the uniformity of the coal sample; on the other hand, the microwave has strong penetrating power and small heating inertia, so that the temperature change can be quickly controlled.

(2) The microwave generator transmits microwaves to the microwave energy applicator by using the microwave transmitter (waveguide tube) to heat the coal sample, and the microwave generator is not in direct contact with the coal sample, so that the condition that the coal sample is heated locally and heated and then gradually diffused can be avoided, the heating uniformity of the coal sample is further improved, and the accuracy and reasonability of an experiment are ensured; on the other hand, the waveguide tube is used for microwave transmission, so that loss can be reduced as much as possible in the microwave transmission process, and the high efficiency of the heating rate is ensured.

(3) The box door arranged on the microwave energy applicator (resonant cavity) is convenient for taking and placing the coal sample bearing mechanism for replacing the coal sample; and the heat-insulating coating coated in the cavity of the resonant cavity is convenient to realize and maintain the constant temperature state of the coal sample after the coal sample reaches the heating temperature.

(4) The heat radiation fan arranged in the microwave electrical appliance control box can radiate heat and cool high-power components such as a transformer, a magnetron and the like, and ensure the long-term normal operation of equipment.

(5) The speed motor and the power regulator motor arranged in the temperature controller can realize the accurate control of the heating speed and the heating power of the microwave generator (magnetron) under the control of a computer, can effectively ensure the accurate controllability of experimental conditions, and reduces the deviation of experimental results.

(6) The electromagnetic valve arranged on the communication pipeline between the gas chromatograph and the coal sample bearing mechanism can realize the interval sampling of the gas chromatograph in the experimental process, and can ensure the reasonability of gas collection and the accuracy of gas analysis; and the basin of the extra intercommunication of coal sample bearing mechanism can in time handle the gas that releases through coal sample bearing mechanism when the solenoid valve disconnection, can guarantee the good circulation of gas in the coal sample bearing mechanism, avoids gaseous long-term delay and then influences the condition emergence of follow-up gas chromatograph gas sample collection accuracy nature.

(7) The coal sample bracket arranged at the bottom of the coal sample tank can ensure the reasonability of coal sample filling; the end cover arranged on the top is convenient for filling and replacing the coal sample, and the temperature sensor sleeve arranged on the end cover is also convenient for inserting the temperature sensor and ensures the contact between the temperature sensor and the coal sample to be good.

(8) The asbestos net covered on the coal sample bracket at the bottom of the coal sample tank can prevent the coal sample from blocking the pipeline and ensure the uniformity of gas flowing in the coal sample.

(9) Through analysis and research of a large number of experimental processes, the diameter of the coal sample tank is set to be 30-50 mm, so that the uniformity of heating of the coal sample in the coal sample tank and the reasonable accuracy of subsequent gas collection are guaranteed.

The invention also discloses a coal spontaneous combustion program temperature control method by utilizing microwave heating, and the coal spontaneous combustion program temperature control system by utilizing microwave heating comprises the following steps in sequence:

s1, filling a coal sample: after the coal sample is filled in the coal sample bearing mechanism, the temperature sensor is inserted, and the real-time communication between the electric control mechanism and the gas chromatograph and the computer is ensured;

s2, temperature programming: introducing gas into the coal sample bearing mechanism, and controlling the gas flow through a computer; then heating and heating the coal sample carrying mechanism by using a microwave generator, and setting the frequency value of the microwave to be 2.45GHz and the heating power value to be 1.2-1.6 kw through a computer; meanwhile, the heating time of 3-5 s is ensured;

s3, temperature control mode: and (3) closing the microwave generator, stopping heating, monitoring the temperature of the coal sample through a temperature sensor, extracting gas samples once every 10-15 ℃, analyzing the gas by using a gas chromatograph, and transmitting data results to a computer.

Due to the adoption of the technical scheme, compared with the prior art, the invention has the following beneficial effects:

(1) according to the coal spontaneous combustion program temperature control method, the temperature rise and the temperature control and the constant temperature of the coal sample can be quickly controlled through the computer, the operation is simple, the time consumption is short, the experiment workload of operators can be greatly reduced, the generated process data and the experiment result can be visually displayed on the computer, and the subsequent analysis and processing of the operators are facilitated.

(2) In the coal spontaneous combustion program temperature control method, the frequency value of the microwave is set to be 2.45GHz, and the heating power value is set to be 1.2-1.6 kw, so that the problem of the actual microwave heating effect and the industrial energy consumption ratio can be effectively solved, and the optimal heating effect on the coal sample is ensured.

In conclusion, the coal sample heating device is reasonable in structure, simple to operate, high in safety and stability, capable of guaranteeing rapid and uniform heating of the coal sample, and capable of achieving controllability of heating rate, further capable of meeting different experimental requirements and greatly improving accuracy of experimental results.

The invention is suitable for being used in the research of coal spontaneous combustion characteristics, and is used for analyzing and researching the oxygen consumption condition and the gas generation amount of coal samples with different metamorphism degrees and different particle sizes under different oxygen concentrations and temperature programming conditions.

Drawings

The invention is described in further detail below with reference to the figures and the embodiments.

FIG. 1 is a schematic view of the overall structure of embodiment 1 of the present invention;

FIG. 2 is a schematic structural view of a heating mechanism according to embodiment 1 of the present invention;

FIG. 3 is a schematic view of a partial structure of a coal sample tank according to embodiment 1 of the present invention;

FIG. 4 is a schematic circuit diagram of a temperature control module according to embodiment 1 of the present invention;

in the figure: 1. a heating mechanism; 2. a coal sample carrying mechanism; 3. a microwave electric appliance control box; 4. a magnetron; 5. a transformer; 6. a heat radiation fan; 7. a resonant cavity; 8. a waveguide; 9. a coal sample tank; 10. a coal sample tank tray; 11. an end cap; 12. a temperature sensor sleeve; 13. a gas cylinder; 14. a gas chromatograph; 15. a water tank; s1, a main switch; s2, a speed motor switch; s3, a power regulator motor switch, an MD and a speed motor; MV, power regulator motor.

Detailed Description

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the description of the preferred embodiment is only for purposes of illustration and understanding, and is not intended to limit the invention.

Embodiment 1 coal spontaneous combustion program temperature control system using microwave heating

As shown in fig. 1 to 4, the present embodiment includes a heating mechanism 1, a coal sample carrying mechanism 2, an electric control mechanism, and a gas collecting and analyzing mechanism, which cooperate with each other. The embodiment adopts a microwave heating mode, so that the coal sample is rapidly heated, the heating uniformity of the coal sample is ensured, and the adjustability and controllability of the heating rate of the coal sample are realized.

First, heating mechanism 1

The heating mechanism 1 is a core component of this embodiment, and is configured to emit microwaves, so as to heat the coal sample. As shown in fig. 2, the heating means 1 includes a microwave generator, a microwave energy applicator, and a microwave transmitter. The microwave generator comprises a magnetron 4 and a transformer 5 which are arranged in a microwave appliance control box 3, wherein the transformer 5 is electrically connected with the magnetron 4 and provides required voltage for the magnetron 4. In order to ensure the safety and stability of power supply, in this embodiment, a high voltage diode is further disposed on the connection line between the transformer 5 and the magnetron 4. Because the magnetron 4 and the transformer 5 are high-power components and generate a large amount of heat during operation, a heat dissipation fan 6 for dissipating heat of components is further arranged in the microwave appliance control box 3 in the embodiment.

The microwave energy applicator, namely the resonant cavity 7, is used for placing the coal sample bearing mechanism 2 and realizing the high-efficiency application of microwave energy. The resonant cavity 7 is integrally made of non-ferromagnetic materials, and the front surface of the resonant cavity is provided with a box door so as to facilitate the taking and placing of the coal sample bearing mechanism 2; the cavity of the resonant cavity 7 is coated with a heat-insulating coating so that the coal sample can be kept in a constant temperature state after reaching the heating temperature.

The microwave transmitter is used for transmitting the microwaves generated by the magnetron 4 into the resonant cavity 7, so that the coal sample is heated in the resonant cavity 7. In order to reduce the loss of the microwave during transmission as much as possible, the present embodiment uses the waveguide 8 as a microwave transmitter, and as shown in fig. 2, the waveguide 8 is disposed at the upper end of the microwave control box 3 communicating with the resonant cavity 7.

Second, coal sample bearing mechanism 2

The coal sample bearing mechanism 2 is integrally arranged in the resonant cavity 7 and is used for bearing a coal sample and simulating the spontaneous combustion phenomenon of the coal under the action of the heating mechanism 1. As shown in fig. 1 or fig. 2, the coal sample bearing mechanism 2 includes a coal sample tank 9 and a coal sample tank tray 10, the coal sample tank tray 10 is fixedly connected to the bottom of the resonant cavity 7, and the coal sample tank 9 is placed on the coal sample tank tray 10. The coal sample tank 9 is made of a ceramic material capable of transmitting microwaves, is of a cylindrical structure, and considers that the diameter of the coal sample tank 9 affects the uniformity of temperature distribution, and the coal sample is heated unevenly when the diameter is too large or too small, so that the diameter of the coal sample tank 9 is selected to be 30-50 mm in the embodiment. In order to reduce the loss of heat in the experimental process, the heat-insulating layer is arranged on the inner side wall of the coal sample tank 9.

More specifically, in order to ensure the rationality of the filling distribution of the coal sample in the coal sample tank 9, a coal sample bracket is welded at the bottom of the coal sample tank 9; in order to ensure that the gas can be in uniform contact with the coal sample in the coal sample tank 9 and prevent the coal sample from blocking the pipeline, the through-hole partition plate is adopted as the coal sample bracket in the embodiment, and the through-hole partition plate is covered with a layer of asbestos cloth. As shown in fig. 3, in order to facilitate the filling of the coal sample, a detachable end cover 11 is disposed at the top of the coal sample tank 9, an air outlet capable of communicating with the gas collecting and analyzing mechanism is disposed on the end cover 11, and a temperature sensor sleeve 12 facilitating the insertion of a temperature sensor is further fixedly disposed. One end of the temperature sensor sleeve 12 is hermetically welded with the end cover 11, and the other end extends into the coal sample tank 9. Since the present embodiment uses the thermocouple as the temperature sensor, the temperature sensor sleeve 12 in the present embodiment is also a thermowell.

Third, electric control mechanism and gas collection and analysis mechanism

The electric control mechanism comprises a temperature control module and a gas flow control module, the temperature control module is used for detecting the temperature of the coal sample and realizing the control of the heating power of the coal sample, and the gas flow control module is used for controlling the flow of gas introduced into the coal sample. Wherein, the temperature control module comprises a temperature controller and a temperature sensor arranged in the coal sample bearing mechanism 2 through a temperature sensor sleeve 12. The temperature controller comprises a speed motor MD and a power regulator motor MV which are connected with a computer and controlled by the computer, and the specific circuit connection relationship is shown in figure 4. In the experimental process, the rate motor MD and the power regulator motor MV are controlled by a computer, so that the temperature rise rate and the heating power of the coal sample can be accurately controlled. In this embodiment, the temperature sensor is a thermocouple connected to the computer.

The gas flow control module comprises a gas cylinder 13 communicated with the bottom of a coal sample tank 9 in the coal sample bearing mechanism 2 through a pipeline, a pressure controller arranged inside the gas cylinder 13 and a flow controller arranged on a connecting pipeline of the gas cylinder 13 and the coal sample tank 9, wherein the pressure controller and the flow controller are respectively connected with a computer, and in the experimental process, the monitoring and the control of the gas diffusion speed can be realized through the computer.

The gas collection and analysis mechanism is used for collecting and analyzing the gas sample passing through the coal sample tank 9. The gas collection and analysis mechanism comprises a gas chromatograph 14 communicated with the top of a coal sample tank 9 in the coal sample bearing mechanism 2 through a pipeline, wherein an electromagnetic valve is further arranged on the connecting pipeline of the gas chromatograph 14 and the coal sample tank 9 and is connected with a computer and used for controlling the on-off of gas so as to realize the interval sampling of the gas chromatograph 14 in the experimental process.

In order to discharge the gas in the coal sample tank 9 in time in the off state of the electromagnetic valve and avoid the influence of long-term retention of the gas on the sampling accuracy and real-time performance of the subsequent gas chromatograph 14, in this embodiment, the top of the coal sample tank 9 is further communicated with the water tank 15 through a pipeline, and the specific structure is as shown in fig. 1.

Embodiment 2 coal spontaneous combustion program temperature control method by microwave heating

This example utilizes the coal auto-ignition programmed temperature control system of example 1, comprising the following steps performed in sequence:

step S1, filling coal sample

Opening the door of the microwave energy applicator (namely the resonant cavity 7), taking out the coal sample tank 9, uniformly filling the coal sample crushed to a certain particle size into the coal sample tank 9, arranging a layer of asbestos gauze above the coal sample, covering the end cover 11, inserting the temperature sensor (namely a thermocouple), and then putting the coal sample tank 9 into the microwave energy applicator. Meanwhile, all the components in the electric control mechanism and the gas chromatograph 14 can be ensured to be communicated with the computer in real time.

S2, temperature programming

Gas in the gas cylinder 13 is introduced into the coal sample tank 9 of the coal sample bearing mechanism 2, corresponding gas flow is set in the computer according to actual experiment requirements, and the computer realizes accurate control of the gas flow through the pressure controller and the flow controller.

The coal sample bearing mechanism 2 is heated and warmed by a microwave generator (namely a magnetron 4), and the heating and warming method specifically comprises the following steps: firstly, setting a microwave frequency value of a microwave generator to be 2.45GHz, setting a heating power value to be 1.2-1.6 kw and setting a heating time to be 3-5 s by a computer; then the main switch S1 is closed, at this time, the microwave generator is in a standby state; then, after the computer adjusts the power governor motor MV to the desired gear, the power governor motor switch S3 is closed, and after the rate motor MD is adjusted to the desired temperature increase rate, the rate motor switch S2 is closed. At the moment, the transformer 5 supplies power to the microwave generator to generate 2.45GHz microwave energy, the microwave energy is transmitted into the microwave energy applicator through the microwave transmitter, polar molecules of the coal sample in the coal sample tank 9 are deflected under the influence of an external alternating electromagnetic field, and then the internal vibration generates heat, so that the temperature rise effect is achieved.

S3 temperature control mode

After the heating time is 3-5 s, automatically closing the microwave generator by the computer, and stopping heating; meanwhile, the temperature of the coal sample is monitored through a temperature sensor, when the temperature changes by 10-15 ℃, the electromagnetic valve is controlled by the computer to be opened briefly, the gas sample is extracted once, the gas chromatograph 14 is used for analyzing the gas, and then the data result is transmitted and stored in the computer for the operator to analyze next step.

Although the present invention has been described in detail with reference to the above embodiments, it will be apparent to those skilled in the art that modifications may be made to the embodiments described above, or equivalents may be substituted for elements thereof. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.