Microwave-assisted plasma ignition system for thermal power plant

Abstract

The utility model relates to the field of ignition systems, in particular to a microwave-assisted plasma ignition system for a thermal power plant. Comprising an ignition module, a microwave auxiliary module and a control unit, and the ignition module and the microwave auxiliary module are both connected with the control unit; the ignition module comprises an ignition coil and a spark plug, and the ignition coil is used for providing high-voltage electricity for the spark plug; the microwave-assisted module provides additional microwave energy for the ignition module under the coordination of the control unit, and the microwave-assisted module comprises a microwave generating device, a microwave amplifier and a mixer; the microwave amplifier is used for adjusting the power of microwaves generated by the microwave generating device, and the mixer is used for mixing high-voltage electricity output by the ignition coil and microwave energy adjusted by the microwave amplifier and transmitting the mixed energy to the spark plug. By means of the structure and a corresponding control method, balance between ignition performance and durability is achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of ignition systems, in particular to a microwave-assisted plasma ignition system for a thermal power plant. Background Art

[0002] The ignition system is one of the important equipment used by coal-fired (thermal) power plants to start and maintain the combustion process. It can ignite the mixture of coal powder and air and maintain combustion, and then use the heat generated by the combustion process to drive the turbine to generate electricity. At present, the ignition system of traditional coal-fired power plants generally adopts flame ignition technology or electric spark ignition technology. These ignition technologies have problems such as low ignition energy, unstable ignition and poor adaptability. In particular, when achieving ultra-low load combustion and burning lean mixed gases, the ignition success rate is low; at the same time, as environmental protection regulations have stricter requirements on pollutant emissions, traditional coal-fired power plants are faced with the dual challenges of improving combustion efficiency and reducing pollution emissions.

[0003] Improving the ignition system is one of the effective means to improve power generation efficiency and reduce pollution emissions. In recent years, in order to effectively increase the ignition energy and enhance the reliability and stability of ignition, people have studied and proposed a variety of new ignition technologies. Among them, the microwave-assisted plasma ignition system for thermal power plants is an emerging technology that can use microwave energy to generate a large volume of high-energy plasma, thereby achieving effective ignition and combustion of dilute mixed gases and improving combustion efficiency. However, microwave-assisted plasma ignition technology is less used in the field of coal-fired power plants. Therefore, the present application aims to apply microwave-assisted plasma ignition technology to the ignition system of a coal-fired power plant, and to provide a high-efficiency and high-stability ignition system for a thermal power plant. Utility Model Content

[0004] The purpose of the utility model is to overcome the above-mentioned deficiencies of the prior art and provide a microwave-assisted plasma ignition system for a thermal power plant, which can significantly improve the ignition stability and combustion efficiency of the boiler of a coal-fired power station, improve energy utilization efficiency and achieve environmentally friendly emissions.

[0005] The technical scheme of the utility model is: a microwave-assisted plasma ignition system for a thermal power plant, comprising an ignition module, a microwave-assisted module and a control unit, wherein the ignition module and the microwave-assisted module are both connected to the control unit; the ignition module comprises an ignition coil and a spark plug, wherein the ignition coil is used to provide high voltage electricity to the spark plug; the microwave-assisted module provides additional microwave energy to the ignition module under the coordination of the control unit; the microwave-assisted module comprises a microwave generating device, a microwave amplifier and a mixer; the microwave amplifier is used to adjust the power of the microwave generated by the microwave generating device, and the mixer is used to mix the high voltage electricity output by the ignition coil and the microwave energy adjusted by the microwave amplifier, and transmit the mixture to the spark plug; the mixer comprises a central electrode and a cavity resonator; the cavity resonator is arranged in a microwave path, and the cavity resonator is used to enhance the microwave energy, and also can prevent the high voltage current from flowing back to the microwave path.

[0006] Furthermore, the cavity resonator is cylindrical and is arranged around the central electrode.

[0007] Furthermore, an electromagnetic blocker is provided on one side of the center electrode close to the ignition coil, and the electromagnetic blocker is used to prevent the microwaves superimposed on the center electrode from flowing back toward the ignition coil.

[0008] Furthermore, the microwave frequency generated by the microwave auxiliary module is 2.45 GHz, and the output power is at the level of 1 kW. The microwave generating device can generate continuous or pulsed microwave energy for exciting plasma.

[0009] Furthermore, the ignition system also includes a sensor, which is used to monitor the temperature and pressure in the combustion chamber and feed back the signal to the control unit.

[0010] Further, the control unit includes a micro control unit (MCU), and the micro control unit is used to control the pulse width, duration and output level of the microwaves generated by the microwave auxiliary module.

[0011] Furthermore, the control unit can also be used to adjust the microwave transmission power and spark intensity of the microwave auxiliary module in real time according to parameters such as the type, particle size, humidity of the coal powder and the temperature of the boiler.

[0012] Compared with the prior art, the utility model has the following beneficial effects:

[0013] 1. This ignition system can achieve a more uniform and extensive plasma distribution, thereby achieving ultra-low fuel consumption in the boiler of a coal-fired power station, which helps to improve the thermal efficiency of the entire power generation system; the ignition system in this application achieves stable generation and maintenance of plasma by precisely controlling the output of microwaves, and can cope with various complex conditions encountered during the ignition process of a coal-fired power station, such as changes in coal quality, humidity, and particle size, to ensure the stability and reliability of ignition; the ignition system in this application can also be combined with the control system of the power station, and can adjust the output power and frequency of the microwave according to the actual operating conditions, achieve precise control of the ignition process, and enhance the adaptability and flexibility to complex combustion environments;

[0014] 2. The microwave-assisted plasma ignition system of the present application can achieve more complete and efficient combustion, significantly reducing the emission of unburned coal powder, thereby reducing the generation of harmful gases such as NOx and SOx, and helping coal-fired power plants meet more stringent environmental protection standards;

[0015] 3. Compared with the traditional ignition system, the ignition system proposed in this application uses high-frequency microwave excitation, which reduces the physical wear of the ignition device during the ignition process, thereby extending the service life of the ignition device and reducing maintenance costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the principle of mixing microwave energy and high voltage electricity in Example 1 of the utility model. DETAILED DESCRIPTION

[0017] The present invention will be further described in detail below in conjunction with specific embodiments. Methods or functional components not specifically described in the embodiments are all prior art. Unless otherwise defined, all technical terms and scientific terms used in this document have the same meanings as those generally understood by technicians in this technical field.

[0018] Example 1

[0019] like Figure 1As shown, the microwave-assisted plasma ignition system for thermal power plants in this embodiment includes an ignition module, a microwave-assisted module and a control unit, and the ignition module and the microwave-assisted module are both connected to the control unit; the ignition module includes an ignition coil and a spark plug, and the ignition coil is used to provide high voltage electricity to the spark plug; the microwave-assisted module provides additional microwave energy to the ignition module under the coordination of the control unit; the microwave frequency produced by the microwave-assisted module is 2.45GHz, and the output power is at the level of 1kW. The microwave-assisted module includes a microwave generator, a microwave amplifier and a mixer; the microwave amplifier is used to adjust the power of the microwave generated by the microwave generator, and the mixer is used to mix the high voltage electricity output by the ignition coil and the microwave energy adjusted by the microwave amplifier, and transmit them to the spark plug; the mixer includes a central electrode and a cavity resonator; the cavity resonator is configured in the microwave path to prevent the high voltage current from flowing back to the microwave path.

[0020] In this embodiment, the cavity resonator is cylindrical and is arranged around the central electrode. An electromagnetic blocker is provided on the side of the central electrode close to the ignition coil, and the electromagnetic blocker is used to prevent the microwaves superimposed on the central electrode from flowing back toward the ignition coil, that is, to prevent the microwaves from transmitting in the direction of the ignition coil, thereby improving the utilization rate of microwave energy.

[0021] In this embodiment, the ignition system further includes a sensor, which is used to monitor the temperature and pressure in the combustion chamber and feed back the signal to the control unit.

[0022] In this embodiment, the control unit includes a microcontroller unit (MCU), which is used to control the pulse width, duration and output level of the microwaves generated by the microwave auxiliary module. The control unit can also be used to adjust the microwave transmission power and the intensity of the electric spark of the microwave auxiliary module in real time according to parameters such as the type, particle size, humidity of the pulverized coal and the temperature of the boiler.

[0023] The working process of this embodiment is as follows: during the ignition process, the control unit first triggers the ignition device, and the ignition coil in the ignition device generates a high-voltage electric spark. Then, in the initial stage of spark generation, the microwave auxiliary module is activated and emits microwave energy. The microwave energy is superimposed on the high-voltage electric spark through the mixer, that is, the mixer superimposes the microwave energy on the high-voltage electricity generated by the ignition coil, and generates a higher-energy plasma at the position of the spark plug. These plasmas can quickly ignite the coal powder in the coal-fired boiler to achieve efficient combustion.

[0024] The above are only some embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have combinations and modifications of the aforementioned technical features. Without departing from the spirit and scope of the present invention, those skilled in the art may improve, modify, or replace the present invention with equivalents, or apply the structure or method of the present invention to other fields to achieve the same effect, which all fall within the scope of protection of the present invention.

Claims

1. A microwave-assisted plasma ignition system for a thermal power plant, comprising an ignition module, wherein the ignition module comprises an ignition coil and a spark plug, wherein the ignition coil is used to provide high voltage electricity to the spark plug; characterized in that: It also includes a microwave auxiliary module and a control unit, and the ignition module and the microwave auxiliary module are both connected to the control unit; the microwave auxiliary module provides additional microwave energy to the ignition module under the coordination of the control unit; The microwave auxiliary module includes a microwave generator, a microwave amplifier and a mixer; the microwave amplifier is used to adjust the power of the microwave generated by the microwave generator, and the mixer is used to mix the high voltage electricity output by the ignition coil and the microwave energy adjusted by the microwave amplifier, and transmit them to the spark plug; The mixer comprises a central electrode and a cavity resonator; the cavity resonator is arranged in a microwave path, and is used to enhance microwave energy and prevent high voltage current from flowing back to the microwave path.

2. The microwave-assisted plasma ignition system for a thermal power plant according to claim 1, characterized in that: The cavity resonator is cylindrical and is arranged around the central electrode.

3. The microwave-assisted plasma ignition system for a thermal power plant according to claim 1, characterized in that: An electromagnetic blocker is provided on one side of the central electrode close to the ignition coil, and the electromagnetic blocker is used to prevent the microwaves superimposed on the central electrode from flowing back toward the ignition coil.

4. The microwave-assisted plasma ignition system for a thermal power plant according to claim 1, characterized in that: The microwave frequency generated by the microwave auxiliary module is 2.45GHz and the output power is at the 1kW level.

5. The microwave-assisted plasma ignition system for a thermal power plant according to claim 1, characterized in that: The control unit comprises a micro control unit, and the micro control unit is used to control the pulse width, duration and output level of the microwaves generated by the microwave auxiliary module.

6. The microwave-assisted plasma ignition system for a thermal power plant according to claim 5, characterized in that: Includes sensors that monitor the temperature and pressure in the combustion chamber and feed the signals back to the control unit.

7. The microwave-assisted plasma ignition system for a thermal power plant according to claim 6, characterized in that: The control unit is used to adjust the microwave transmission power and the intensity of the electric spark of the microwave auxiliary module in real time according to the type, particle size, humidity of the coal powder and the temperature parameters of the boiler.

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