Laser ignition device for thermal combustion

Abstract

The present invention provides a laser ignition device for thermal combustion, comprising: a light generating assembly, a light transmission assembly, an ignition assembly, and a light blocking assembly. The light generating assembly includes a first light source configured to emit a first light beam, the first light beam being a laser. The light transmission assembly is configured to transmit the first light beam to the ignition assembly. The ignition assembly includes a light guiding assembly and an ignition nozzle located at the end of the light guiding assembly. The light guiding assembly is configured to guide the first light beam along a guiding direction and ejected through the ignition nozzle for ignition. The light blocking assembly is located on a side of the ignition nozzle away from the light guiding assembly in the guiding direction and is configured to block the entire first light beam ejected from the ignition nozzle. The laser ignition device utilizes laser-assisted ignition, which not only serves as an ignition device but also assists and stabilizes combustion.

Description

Technical Field

[0001] The present invention relates to the technical field of energy beam ignition of high-power thermal combustion equipment, in particular to a laser ignition device for high-power thermal combustion. Background Art

[0002] Thermal power generation is a typical application of high-power (power of 0.14Mw and above) thermal combustion. Currently, thermal power generation is still the main way to provide electricity. Due to the good economic efficiency of coal-fired power generation, "coal-fired power" accounts for a large proportion of "thermal power", especially in developing countries. It is also one of the main sources of air pollution. High-power "coal-fired power" boilers all use pulverized coal burners without exception.

[0003] With the rapid increase in the urgency of global greenhouse gas emissions reduction, high-power pulverized coal combustion technology will develop in the direction of "green combustion" with higher efficiency, energy saving and lower emissions. It is necessary to further improve the level of combustion technology. On the basis of refined combustion and intelligent control, it is also necessary to study safer, more reliable, convenient and economical energy beam ignition devices. Summary of the Invention

[0004] The embodiment of the present invention provides a laser ignition device for thermal combustion, which uses laser-assisted ignition to not only ignite, but also assist and stabilize combustion. Therefore, the laser ignition device of the present invention is a beam ignition technology.

[0005] The laser ignition device for thermal combustion provided by the present invention includes: a light generating component, a light transmission component, an ignition component and a light blocking component, wherein: the light generating component includes a first light source, the first light source is configured to emit a first light beam, and the first light beam is a laser; the light transmission component is configured to transmit the first light beam to the ignition component; the ignition component includes a light guiding component and an ignition nozzle located at the end of the light guiding component, the light guiding component is configured to guide the first light beam along a guiding direction to be emitted through the ignition nozzle for ignition; in the guiding direction, the light blocking component is located on the side of the ignition nozzle away from the light guiding component and is configured to block all of the first light beam emitted from the ignition nozzle.

[0006] In some embodiments, the light generating assembly further includes: an air supply component configured to provide a purification gas to the first light beam; and the light transmitting component further configured to transmit the purification gas and the first light beam along the same optical path to the ignition assembly and eject the gas from the ignition nozzle.

[0007] In some embodiments, the light generating assembly further comprises: a phosgene combining component configured to receive and combine the first light beam and the purge gas, and transmit the combined first light beam and the purge gas to the light transmitting component.

[0008] In some embodiments, the light generating assembly further includes: a collimating component, which is configured to collimate the first light beam; a second light source, which is configured to emit a second light beam, and the second light beam is visible light to be used as an indicator light; wherein the second light beam is configured to be transmitted along the same optical path as the collimated first light beam through the light generating assembly, the light transmitting component and the light guiding component to the ignition nozzle and be emitted from the ignition nozzle.

[0009] In some embodiments, the light generating assembly further includes: a gas supply component configured to provide a purified gas to the first light beam; a phosgene combination component configured to receive and collect the collimated first light beam, the second light beam, and the purified gas, and transmit the collected collimated first light beam, the second light beam, and the purified gas to the light transmission component.

[0010] In some embodiments, the phosgene assembly component includes: a first input port, a second input port, and an output port; the first input port is configured to receive the collimated first light beam and the second light beam; the second input port is configured to receive the purge gas; and the output port is configured to output the collected collimated first light beam, the second light beam, and the purge gas to the light transmission component.

[0011] In some embodiments, there are multiple light generating components, multiple first light sources emit multiple first light beams, multiple second light sources emit multiple second light beams, and multiple gas supply components provide multiple purification gases; the light transmission component is configured to collect the multiple first light beams and the multiple second light beams to form a collected light beam, and transmit the collected light beam to the ignition component so that the collected light beam is emitted from the ignition nozzle; the light transmission component is also configured to mix the multiple purification gases to form a mixed purification gas and transmit the mixed purification gas to the ignition component so that the mixed purification gas is emitted from the ignition nozzle.

[0012] In some embodiments, the mixed purge gas forms a purge gas diffusion zone within the injection region of the ignition nozzle, and the concentrated light beam is transmitted to the light blocking component through the purge gas diffusion zone.

[0013] In some embodiments, the light blocking component has an optically reflective surface configured to reflect the concentrated light beam emitted from the ignition nozzle.

[0014] In some embodiments, the optical reflective surface is a convex quadratic surface facing the ignition nozzle, and the convex quadratic surface is configured to form a divergent reflection on the concentrated light beam.

[0015] In some embodiments, a laser ignition area is provided between the ignition nozzle and the optical reflective surface; a spatial distance along the guiding direction is provided between the ignition nozzle and the optical reflective surface, and the laser ignition area is the area from 1 / 2 of the spatial distance to the optical reflective surface.

[0016] In some embodiments, the first light source is an infrared laser source, and the laser is an infrared laser. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings of the embodiments will be briefly introduced below. Obviously, the drawings in the following description only relate to some embodiments of the present invention, but are not intended to limit the present invention.

[0018] Figure 1 This is a schematic structural diagram of a laser ignition device according to an embodiment of the present invention;

[0019] Figure 1A Schematic diagram of the optical path of the collimating component according to an embodiment of the present invention;

[0020] Figure 2A This is a schematic structural diagram of a phosgene assembly component according to an embodiment of the present invention;

[0021] Figure 2B This is a schematic structural diagram of a phosgene assembly component according to another embodiment of the present invention;

[0022] Figure 3A Schematic diagram of the structure of an optical transmission component according to an embodiment of the present invention;

[0023] Figure 3B A schematic structural diagram of an optical transmission component according to another embodiment of the present invention;

[0024] Figure 3C Schematic diagram of a light spot after light beams converge according to an embodiment of the present invention;

[0025] Figures 4A to 4F FIG. 4 is a schematic diagram of a light spot after light beams are converged according to an embodiment of the present invention.

[0026] Figure 5 A schematic structural diagram of a light guiding component, an ignition nozzle, and a light blocking component according to an embodiment of the present invention;

[0027] Figure 6 A schematic diagram of a light path of a light blocking component according to an embodiment of the present invention;

[0028] Figure 7 is another light path schematic diagram of a light blocking component according to an embodiment of the present invention;

[0029] Figure 8 Schematic diagram of the structure of the thermal combustion equipment according to an embodiment of the present invention. DETAILED DESCRIPTION

[0030] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the described embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of the present invention.

[0031] Unless otherwise defined, the technical or scientific terms used herein shall have the ordinary meaning understood by persons of ordinary skill in the field to which the invention belongs. The words "first", "second" and similar terms used in the patent application specification and claims of the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. Words such as "include" or "comprise" and similar words mean that the elements or objects appearing before "include" or "comprise" include the elements or objects listed after "include" or "comprise" and their equivalents, and do not exclude other elements or objects. Words such as "connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0032] As we all know, electricity must be used immediately, making it difficult to store in large capacities. To date, existing methods for converting and storing electricity, such as hydropower, compressed or liquefied air, and flywheels, have been unsatisfactory, and new, ideal large-scale storage technologies are still under development. Consequently, the thermal power industry suffers from a serious problem of curtailed electricity, which wastes resources and pollutes the environment. While this curtailed electricity can be reused, it still results in energy consumption and air pollution.

[0033] How to further improve the efficiency of coal-fired power and fundamentally address the engineering challenges of large-scale storage of curtailed electricity is a key concern within the industry. Rather than passive energy storage, active deep peak shaving is preferable. This allows coal-fired units to respond quickly to large-scale dynamic load changes with acceptable temperature and voltage ramps, minimizing curtailment and achieving optimal energy conservation and emissions reductions.

[0034] The ignition method is crucial for the startup of high-power pulverized coal boilers, especially when they are completely cold. It is also a key step in achieving active "deep peak load regulation." Traditionally, the ignition, combustion support, and combustion stabilization methods for high-power pulverized coal boilers have relied on oil or gas. These methods are time-consuming, costly, and generate significant pollution during the initial stages of ignition.

[0035] The plasma ignition technology proposed at the beginning of this century is superior to traditional methods in terms of ignition, combustion support and stable combustion, but it still has obvious shortcomings:

[0036] 1. Time-consuming: ignition, combustion support and stable combustion require several hours, more than ten hours, dozens of hours or even hundreds of hours;

[0037] 2. Limited ignition energy: Current gas discharge technologies, whether DC or AC, struggle to generate large plasma volumes. Therefore, the plasma ignition energy, which serves as the "spark," is limited. While step-by-step ignition and amplified combustion techniques can be used to increase the final main ignition energy, the pulverized coal machine has a minimum load limit. This creates an objective mismatch between the initial plasma ignition energy and the minimum pulverized coal feed rate, making safe and reliable ignition impossible. Furthermore, factors such as changes in ambient humidity and the moisture content of pulverized coal can cause the latent heat of vaporization to consume some of the ignition energy, further reducing ignition reliability and creating a significant safety hazard of deflagration due to ignition failure. Increasing the plasma volume to increase the ignition energy would increase the size, weight, complexity, and cost of the discharge device, making it difficult to implement in engineering.

[0038] 3. There are safety hazards: The operation process must be to discharge first, and then supply air and coal powder for ignition after successful arc drawing. However, successful arc drawing does not guarantee successful ignition, because the instant of supplying air and coal powder changes the discharge environment, which may quench the arc and cause ignition failure. Even if the arc is successfully drawn again when continuing to supply air and coal powder, explosion may occur due to the arcing interval time. There are major safety hazards, and it is difficult to avoid through human operation.

[0039] 4. Limited coal types: Due to the limited energy of a certain volume of plasma, reliable ignition requires that the air-dry basis volatile matter of the coal powder must be greater than 18%. For very lean coal with a ratio lower than this, oxygen-enriched or pure oxygen is required to assist combustion for ignition, which will undoubtedly increase the ignition cost, operation complexity and safety risks. Therefore, plasma ignition has requirements for the type of coal in the pulverized coal furnace, and not all coal can be ignited.

[0040] 5. Limited ignition application: Existing plasma ignition technology is only applicable to pulverized coal boilers or gas boilers and cannot be used for ignition of solid fuel boilers, such as fluidized beds and biomass fuel boilers.

[0041] 6. Technical defects of the device: Existing plasma igniters all adopt an internal combustion type with an integrated structure with the main combustion equipment. The inner wall of the burner has to withstand high temperatures of several hundred degrees. Although cooling air is used to avoid flames sticking to the wall, coal powder flowing against the wall, and coking, these phenomena cannot be eliminated. It is necessary to strictly control the temperature of the inner wall of the burner and not to exceed 600℃ for a certain period of time. This requires temperature measurement and temperature control measures, which increases the complexity of the equipment and affects reliability.

[0042] In summary, whether it is traditional fuel or gas ignition or plasma ignition method, there are safety hazards and technical defects. Exploring and developing new ignition systems has important social significance, great economic benefits and real market demand.

[0043] To this end, an embodiment of the present invention provides a laser ignition device for thermal combustion, comprising a light generating assembly, a light transmission component, an ignition assembly, and a light blocking component. The light generating assembly includes a first light source configured to emit a first light beam, the first light beam being a laser; the light transmission component is configured to transmit the first light beam to the ignition assembly; the ignition assembly includes a light guiding component and an ignition nozzle located at a distal end of the light guiding component, the light guiding component being configured to guide the first light beam in a guiding direction and ejected through the ignition nozzle for ignition; the light blocking component is located on a side of the ignition nozzle away from the light guiding component in the guiding direction and is configured to block the entire first light beam emitted from the ignition nozzle.

[0044] Since laser is the energy beam with the highest power and energy density that humans can achieve so far (for example, infrared laser beam can reach a power density of more than 107W / cm2 or an energy density of more than 107J / cm2), it can generate high temperatures of thousands of degrees and can ignite all combustible materials.

[0045] Compared to traditional ignition methods using fuel oil, gas, and plasma technologies, the ignition system provided by the above-mentioned embodiment of the present invention uses a laser as the ignition energy beam for igniting high-power pulverized coal boilers. This system is not only time-efficient and energy-efficient, but also highly safe and unrestricted by the type of combustible material. Furthermore, because laser energy provides sustainable energy and does not deplete after a period of use like fuel oil and gas, the laser ignition device of the embodiment of the present invention also assists and stabilizes combustion. Furthermore, because the ignition device of the embodiment of the present invention is also equipped with a light-blocking component, it prevents the high-energy laser beam from striking the inner walls of the thermal combustion equipment, making the operation process safer, more convenient, and more economical, and offering broad application prospects. Furthermore, the above-mentioned laser ignition device is suitable not only for igniting high-power combustion equipment, such as pulverized coal boilers, but also for igniting other solid, liquid, and gas fuel boilers, kilns, and the like.

[0046] The present invention is described below by way of specific embodiments. To keep the following description of the embodiments of the present invention clear and concise, detailed descriptions of known functions and components may be omitted. When any component of an embodiment of the present invention appears in more than one drawing, the component may be represented by the same reference numeral in each drawing.

[0047] Figure 1 FIG. 1 is a schematic diagram of the structure of the laser ignition device according to an embodiment of the present invention. Figure 1 As shown, the laser ignition device 100 provided by the embodiment of the present invention includes: light generating components 11 and 12, a light transmission component 20, an ignition component 30, a light blocking component 40 and a fixing component 50.

[0048] In the embodiments of the present invention, the number of light generating assemblies can be one or more. "Multiple" refers to two or more. Using multiple light generating assemblies can generate multiple laser beams, resulting in higher ignition energy and improved safety and stability due to parallelism. This is preferred, and the embodiments of the present invention do not limit the number of light generating assemblies. The specific structure of the light generating assembly is described below using light generating assembly 11 as an example.

[0049] like Figure 1 As shown, the light generating assembly 11 includes a first light source 1 , which is configured to emit a first light beam L1 , which is a laser.

[0050] For example, the first light source 1 is an infrared laser source, and the first light beam L1 is an infrared laser. The wavelength of the infrared laser spectrum can be divided into the near-infrared region (0.75-2.5μm), the mid-infrared region (2.5-25μm), and the far-infrared region (25-1000μm). The first light source 1 can emit infrared lasers in any of the above wavelength bands. Lasers with wavelengths in the infrared spectrum have high-density laser energy and high temperatures. They have good atmospheric penetration in the atmospheric window and are suitable for high-power thermal combustion ignition, especially for use as ignition beams for pulverized coal boilers. In addition, laser sources with wavelengths in the infrared spectrum can set output power according to actual needs, have high beam quality, can work independently, or can be used in parallel, thereby improving the safety and reliability of ignition. By adjusting the output power of a single light source and controlling the start-up timing of multiple light sources, the convenience and economy of ignition are improved.

[0051] For example, Figure 1 As shown, the light generating assembly 11 may further include a collimating component 2 configured to collimate the first light beam L1. This allows the first light beam L1 to be collimated, allowing the light to be efficiently coupled into a desired optical device (e.g., the phosgene assembly 3) for easier transport and collection.

[0052] For example, the collimating component 2 is an optical device for collimation, including a convex lens group, a reflector group, etc. Figure 1A As shown, the collimating component 2 includes a convex lens assembly 21, which shapes the infrared laser light emitted by the first light source 1 into a collimated beam. For example, the diameter of the collimated beam is d1, and the value range of d1 is 0.2 mm ≤ d1 < 500 mm. The collimation length m is m ≥ 10 mm. For example, within the range of m, the variation of d1 is within ±10% of d1. The collimated beam has, for example, a nearly circular cross-sectional shape (i.e., a near-circular spot), with the major axis to minor axis ratio of approximately 1.1:1.

[0053] The embodiment of the present invention is described by taking the collimated light beam having a spot that is approximately circular as an example. It can be understood that in other embodiments of the present invention, the spot of the collimated light beam may also be other shapes, such as elliptical, rectangular, etc., and the embodiment of the present invention does not limit this.

[0054] For example, Figure 1 As shown, the light generating assembly 11 may further include a second light source 4 configured to emit a second light beam L2, which is visible light and serves as an indicator light. The second light beam L2 is configured to be transmitted along the same optical path as the collimated first light beam L1. In other words, the second light beam L2 is transmitted along the same optical path as the collimated first light beam L1 through the light generating assembly 11, the light transmitting component 20, and the light guiding component 7 to the ignition nozzle 8 and is emitted from the ignition nozzle 8.

[0055] For example, the second light beam L2 serves to visualize the laser ignition process; by setting the second light beam L2 to the visible spectrum (e.g., red or green light), it not only has high brightness but also has a safety threshold. Furthermore, by arranging the second light beam L2 to be transmitted along the same optical path as the collimated laser beam, it can be used to indicate the set laser transmission path and the laser ignition spatial position along the same optical path, thereby observing the dust distribution density in the laser transmission space. In particular, before actual laser ignition, an indicator light can be used to achieve "pre-ignition," visually simulating the entire process and scenario of laser ignition to improve the safety, reliability, and convenience of the actual ignition operation. This gives laser ignition the unique advantage of "on-site pre-ignition simulation," something that traditional gas, oil, and plasma ignition methods cannot achieve.

[0056] For example, Figure 1 As shown, the first light source 1 and the second light source 4 are located on different sides of the collimating component 2, so that the first light beam L1 and the second light beam L2 are incident on the collimating component 2 in different directions. The above arrangement can avoid crosstalk between the first light source 1 and the second light source 4.

[0057] It is understandable that Figure 1The illustration is for illustration only. In other embodiments, the first light source 1 and the second light source 4 may be arranged in other ways, such as being arranged on the same side (left side or upper side) of the collimating component 2. This embodiment of the present invention is not limited to this.

[0058] For example, Figure 1 As shown, the light generating assembly 11 may further include a gas supply component 5, which is configured to provide a purge gas G to the first light beam L1, wherein the purge gas G and the first light beam L1 are transmitted along the same optical path to the ignition assembly 30 and are emitted from the ignition nozzle 8. "Transmitted along the same optical path" herein means that the transmission path of the light beam or gas is the same, which can also be referred to as "transmitted along the same optical path."

[0059] During laser transmission, there's no vacuum, so moisture or dust in the environment can attenuate laser energy. By coordinating the purified air G and the first light beam L1 along the same optical path, the adverse effects of moisture and dust on laser energy during laser transmission can be minimized. Furthermore, the system also cools optical components.

[0060] For example, the purified gas G is compressed air, that is, the air is compressed and pressurized by compression, filtration, cold drying or hot drying, particulate matter is filtered out, and moisture is removed by evaporation or condensation to form purified air with a set pressure, dust content level, moisture percentage, and flow rate.

[0061] In this embodiment of the present invention, when the purified gas G passes through the light transmission component 20 and the light guide component 7 and is ejected from the ignition nozzle 8, a purified air diffusion zone (i.e., a purified gas diffusion zone) is purged within the injection area of ​​the ignition nozzle 8, thereby forming a relatively clean light path between the ignition nozzle 8 and the light blocking component 40. Without this diffusion zone, the laser light emitted from the ignition nozzle 8 would be affected by moisture or dust in the surrounding environment before reaching the light blocking component 40, reducing the laser energy. However, by forming a purified air diffusion zone, the laser light (i.e., the focused light beam) is transmitted within this purified air diffusion zone, effectively eliminating the adverse effects of moisture and dust between the ignition nozzle 8 and the light blocking component 40 on the laser energy. Furthermore, the combustion area where the pulverized coal and the laser light come into contact is kept as far away from the ignition nozzle 8 as possible.

[0062] For example, Figure 1 As shown, the light generating assembly 11 may further include a phosgene assembly component 3. The phosgene assembly component 3 receives and combines the collimated first light beam L1, the second light beam L2 and the purge gas G, and transmits the combined collimated first light beam L1, the second light beam L2 and the purge gas G to the light transmission component 20.

[0063] For example, the phosgene assembly 3 is located downstream of the first light source 1 and the second light source 4. "Downstream" in this context means that the first and second light sources 1 and 4 precede the phosgene assembly 3 in the beam propagation path. This allows the first and second light beams L1 and L2 to enter the phosgene assembly 3 over a shorter distance, saving on optical components.

[0064] For example, an optical device may be provided between the phosgene assembly component 3 and the first light source 1, or may not be provided, and this is not limited in the embodiment of the present invention. Figure 1 As shown, for example, the collimating component 2 may be located between the phosgene assembly component 3 and the first light source 1, so that the collimated first light beam L1 and the second light beam L2 traveling along the same optical path enter the phosgene assembly component 3 together. In another example, the collimating component 2 may not be disposed between the phosgene assembly component 3 and the first light source 1. In this way, the first light beam L1 and the second light beam L2 traveling along the same optical path enter the phosgene assembly component 3 directly without passing through the collimating component 2.

[0065] Figure 2A FIG. 1 is a schematic structural diagram of a phosgene assembly component according to an embodiment of the present invention. Figure 2A As shown, the phosgene assembly component 3 includes a first input port 301 , a second input port 302 and an output port 303 .

[0066] For example, the phosgene assembly component 3 is a tubular member 30A. The tubular member 30A includes a front end and a rear end that are opposite to each other in the direction of its extension (e.g., horizontally in the figure), with the rear end being closer to the optical transmission component 20 than the front end. A first input port 301 and a second input port 302 are located at the front end, while an output port 303 is located at the rear end. The first input port 301 receives the collimated first and second light beams L1, L2, and the second input port 302 receives the purge gas G. The output port 303 outputs the combined first and second light beams L1, L2, and purge gas G to the optical transmission component 20.

[0067] For ease of description, the combined first light beam L1, second light beam L2, and purge gas G are referred to herein as a combined phosgene beam LG. The combined phosgene beam formed by the first light generating assembly (e.g., light generating assembly 11) is defined as LG1, the combined phosgene beam formed by the second light generating assembly (e.g., light generating assembly 12) is defined as LG2, the combined phosgene beam formed by the third light generating assembly (not shown) is defined as LG3, and so on.

[0068] For example, the diameter of the tubular member 30A is d2, where d2 > d1. This allows the collimated first and second light beams L1 and L2 to fully enter the first input port 301. For example, d1 is 10 mm, d2 > d1, and d2 is 15 mm. The actual value range of d2 should ensure unimpeded transmission of the laser and indicator light while also ensuring the required purified air pressure at the output port 303. This facilitates purging a purified air diffusion zone T1 outside the output port 303, ensuring that the collimated laser and indicator light have a relatively clean transmission path after leaving the tubular member, reaching the desired spatial location with minimal optical energy loss. In the phosgene assembly component 3, the first and second light beams L1, L2, and purified gas G are coaxially transported within the tubular member 30A in a semi-enclosed state, and are output to the optical transmission component 20 through the output port 303. Herein, "semi-enclosed state" refers to the state where the light beams and / or gas are input from one end of a component and output from the other end.

[0069] Figure 2A In the embodiment, the tubular member 30A is configured as a straight line, and the output port 303 and the first input port 301 are directly opposite each other in the extension direction of the tubular member 30A, so that the output port 303 and the first input port 301 are directly connected to each other. In other embodiments, the tubular member can be configured as a curved line, that is, the output port 303 and the first input port 301 are not directly opposite each other.

[0070] Figure 2B FIG. 1 is a schematic structural diagram of a phosgene assembly component according to another embodiment of the present invention. Figure 2B As shown, the phosgene assembly component 3 ′ includes a first input port 301 ′, a second input port 302 ′ and an output port 303 ′.

[0071] For example, the phosgene assembly component 3' is a tubular member 30A' having a front end and a rear end opposite each other in its extension direction, with the rear end being closer to the optical transmission component 20 than the front end. A first input port 301' and a second input port 302' are located at the front end, while an output port 303' is located at the rear end. The first input port 301' receives the collimated first and second light beams L1, L2, while the second input port 302' receives the purge gas G. The output port 303' outputs the combined first and second light beams L1, L2, and purge gas G to the optical transmission component 20.

[0072] and Figure 2A The difference is that the tubular member 30A' is bent, and the output port 303' and the first input port 301' are not arranged opposite each other in the extension direction of the tubular member 30A.

[0073] In order to ensure that the collimated first light beam L1 and the second light beam L2 are output from the output port 303', the tubular member 30A' may further include a reflector 304', which can reflect the collected first light beam L1 and the second light beam L2 to the output port 303'. Due to the blocking effect of the reflector 304', the purified gas G is also guided to the output port 303'.

[0074] For example, the reflector 304' is an optical reflector, and the angle between the optical reflector and the axial direction of the tubular member 30A' (eg, the horizontal direction shown in the figure) is A, and the value range of A is 0°. <A< 90°。

[0075] from Figure 2A and 2B As can be seen, after the purge gas G is delivered to the phosgene assembly 3, it travels along the same optical path as the collimated first and second light beams L1, L2. Thus, during the transmission of the first and second light beams L1, L2, the purge gas G minimizes the adverse effects of moisture and dust on the laser energy during laser transmission. Furthermore, it also cools optical components (such as the tubular element and optical reflector).

[0076] Figure 2B The diameter of the tubular member 30A' can be referred to Figure 2A The tube diameter d2 is set so that the collimated first light beam L1 and the second light beam L2 can all enter the first input port 301', and it is beneficial to use the purified air G to blow out the purified air diffusion area T1 outside the output port 303'.

[0077] It should be noted that the light generating assembly of the embodiment of the present invention can also be configured without the gas supply component and the phosgene assembly component. Instead, the collimated first and second light beams L1 and L2 can be directly incident on the light transmission component 20 and then transmitted to the ignition nozzle 8, thereby achieving laser ignition. However, this solution reduces reliability and results in a certain amount of laser energy loss, and is therefore not the preferred technical solution of the present invention.

[0078] Alternatively, when the light generating assembly 11 does not include the second light source 4, the phosgene combining component 3 is configured to receive and combine the first light beam L1 and the purge gas G, and transmit the combined first light beam L1 and purge gas G to the light transmitting component 20. This approach can also achieve laser ignition. However, because this solution loses the significant advantage of visual laser "pre-ignition," it is not a preferred technical solution of the present invention.

[0079] For example, Figure 1AAs shown, the laser ignition device 100 may include two light generating assemblies 11 and 12 , wherein two first light sources 1 emit two first light beams L1 , two second light sources 4 emit two second light beams L2 , and two gas supply components 5 provide two paths of purge gas G. The two first light beams L1 , the two second light beams L2 , and the two paths of purge gas G are all delivered to the light transmission component 20 .

[0080] For example, the optical transmission component 20 is used to combine the two first light beams L1 and the two second light beams L2 to form a combined light beam, and transmit the combined light beam to the ignition assembly 30 (e.g., the light guiding component 7) so that the combined light beam is emitted from the ignition nozzle 8. The optical transmission component 20 is also used to mix the two purge gases G to form a mixed purge gas, and transmit the mixed purge gas to the ignition assembly 30 (e.g., the light guiding component 7) so that the mixed purge gas is emitted from the ignition nozzle 8.

[0081] It is understandable that the laser ignition device 100 of the embodiment of the present disclosure may include more than two light generating components. The following description will take the laser ignition device 100 including three light generating components as an example.

[0082] For example, the laser ignition device 100 includes three light generating assemblies, and the three light generating assemblies respectively generate three phosgene combined beams LG1 , LG2 , and LG3 . The three phosgene combined beams LG1 , LG2 , and LG3 are delivered to the light transmission component 20 .

[0083] Figure 3A Schematic diagram of the structure of an optical transmission component according to an embodiment of the present invention.

[0084] For example, Figure 3A As shown, the optical transmission component 20 includes a tubular structure 6, which may be formed, for example, from a tube having a circular or polygonal cross-section. The tubular structure 6 includes three input ports 601 and one output port 602. Each input port 601 is connected to an output port of the phosgene assembly 3. The three input ports 601 are respectively configured to receive three phosgene combined beams LG1, LG2, and LG3. The output ports 602 are connected to the light guide component 7 of the ignition assembly 30, transmitting the combined light beams and the mixed purified gas to the ignition nozzle 8 via the light guide component 7.

[0085] For example, Figure 3A As shown, the light transmission component 20 may further include optical elements (such as four reflectors shown in the figure) disposed in the tubular structure 6 for reflectively bundling the three phosgene combination beams LG1, LG2, and LG3.

[0086] For example, the three first beams L1 and the three second beams L2 of the three combined phosgene beams LG1, LG2, and LG3, traveling along the same optical path, are reflected by optical elements (e.g., the four reflectors shown) within the tubular structure 6 to form converged beams LG1', LG2', and LG3'. Thus, using geometric optics, the originally independently distributed beams LG1, LG2, and LG3 are redirected and optically converged to form horizontally oriented converged beams LG1', LG2', and LG3'. These converged beams LG1', LG2', and LG3' are then transmitted from the output port 602 to the ignition assembly 30.

[0087] For example, the three purified gases in the three phosgene combination beams LG1, LG2, and LG3 are blocked by the optical elements in the tubular structure 6 (such as the four reflectors shown in the figure) and are gathered into one mixed purified gas (not shown in the figure), which is also transmitted from the output port 602 to the ignition assembly 30.

[0088] Optionally, the optical transmission component 20 can also be used to focus the collected beams, reducing their diameter. For example, the diameter of the three combined phosgene beams LG1, LG2, and LG3 before collection is d30, and the diameter after collection and focusing is d3, where d30 > d3 > d2. Compared to their pre-collection diameters, the collected and focused beams LG1', LG2', and LG3' have smaller diameters, resulting in higher laser energy density and better ignition performance.

[0089] Figure 3B Schematic diagram of the structure of an optical transmission component according to another embodiment of the present invention.

[0090] like Figure 3B As shown, for example, the optical transmission component 20' includes a tubular structure 6', which may be formed, for example, of a tube having a circular or polygonal cross-section. The tubular structure 6' includes three input ports 601' and one output port 602'. Each input port 601' is connected to an output port of the phosgene assembly 3. The three input ports 601' are respectively configured to receive three phosgene combined beams LG1, LG2, and LG3. The output port 602' is connected to the light guide component 7 of the ignition assembly 30, transmitting the combined light beams and mixed gas path through the light guide component 7 to the ignition nozzle 8.

[0091] Figure 3A and Figure 3B The difference is: Figure 3A In the process, the three phosgene combination beams LG1, LG2, and LG3 have the same input direction. Figure 3BThe three phosgene combined beams LG1, LG2, and LG3 are input in different directions. Therefore, the three input ports 601' of the tubular structure 6' are arranged in different ways to receive the phosgene combined beams LG1, LG2, and LG3 from different directions.

[0092] in addition, Figure 3B The number and arrangement of optical elements are also different. Figure 3A , Figure 3B There are fewer optical elements (such as the two mirrors shown in the figure), so Figure 3B The tubular structure 6' is more suitable for use when the input directions of the multiple phosgene combined beams are different.

[0093] Figure 3A 、 Figure 3B The number and arrangement of the input ports shown are for illustration only. The number of input ports is determined based on the number of phosgene combination bundles provided by the light generating assembly, and their arrangement can be determined based on the relative positional relationship between the phosgene combination component and the light transmission component. This is not limited in the embodiments of the present invention.

[0094] Figure 3A and Figure 3B The structures of the light transmitting components 20 and 20 ′ shown are merely illustrative. In other embodiments, the light transmitting components 20 and 20 ′ may have other configurations.

[0095] In the disclosed embodiments, the laser ignition device may further include multiple optical transmission components 20. For example, when the number of phosgene combination beams is from a dozen to several dozen, multiple optical transmission components 20 (or optical transmission components 20') may be provided, and these optical transmission components 20 may be divided into multiple stages for combined cascade connection.

[0096] For example, if the laser ignition device includes multiple optical transmission components 20, these components can be arranged in a two-stage cascade: some components 20 are configured as primary components, while the remaining components 20 are configured as secondary components. The secondary components are located downstream of the primary components. The beams collected by the multiple primary components can be further combined by the secondary components to form a single, aggregated beam. This combined cascade arrangement allows for more flexible expansion of the number of combined phosgene beams, allowing for the laser energy required for ignition to be increased at any time based on actual on-site needs. This approach is simple to operate.

[0097] Figure 3C FIG. 1 is a schematic diagram of a light spot after the light beams are converged according to an embodiment of the present invention. Figure 3CAs shown, the light beams LG1 ′, LG2 ′, and LG3 ′ formed by the convergence of the three phosgene combined beams LG1 , LG2 , and LG3 have a triangular combined light spot. Figure 3C The light spot shapes shown are only for illustration purposes. In other embodiments of the present invention, there may be combined light spots of other shapes.

[0098] Figures 4A to 4F Schematic diagram of light spot after light beams converge according to other embodiments of the present invention. Figure 4A The light spots are formed by combining two and three phosgene beams respectively. The light spot pattern on the left is linear, and the light spot pattern on the right is triangular. Figure 4B These are two types of light spots formed after four phosgene beams are combined. The light spot pattern on the left is a three-pointed star, and the light spot pattern on the right is a square. Figure 4C The light spot is formed by combining five phosgene beams, and the light spot pattern is a cross. Figure 4D The light spot is formed by combining six phosgene beams, and the light spot pattern is circular. Figure 4E The light spot is formed by combining seven phosgene beams, and the light spot pattern is hexagonal. Figure 4F The light spot is formed by combining eight phosgene beams, and the light spot pattern is circular.

[0099] from Figures 4A to 4F It can be seen that the transmission directions of the mixed light beams are parallel to each other, so that the laser beam can continue to be transmitted, accurately guided to the set spatial area, and facilitate the required beam transformation such as focusing.

[0100] In some embodiments, such as Figure 4C and Figure 4E As shown, when there are multiple phosgene combined beams, one phosgene combined beam can be set as the central beam, and the remaining beams are arranged with equal intervals along the circumferential direction of the central beam with the central beam as the center. In other embodiments, as Figure 4D and 4F As shown, all phosgene combined beams can be arranged at equal intervals along the circumferential direction to make the laser energy in the circumferential direction more uniform.

[0101] like Figure 1 As shown, the ignition assembly 30 includes a light guiding component 7 and an ignition nozzle 8 located at the end of the light guiding component 7. The collected light beams LG1', LG2', LG3' and the mixed purified gas are simultaneously incident on the light guiding component 7 through the light transmission component 20 and reach the ignition nozzle 8.

[0102] Figure 5 FIG is a structural diagram of a light guiding component, an ignition nozzle and a light blocking component according to an embodiment of the present invention. Figure 5As shown, the light guiding component 7 plays a guiding role, guiding the collected light beams LG1 ′, LG2 ′, LG3 ′ and the mixed purified gas along a guiding direction R, and ejecting them through the ignition nozzle 8 for ignition.

[0103] For example, the light guide component 7 is a tubular member having an input end 701 and an output end 702. The input end 701 is connected to the output port of the light transmission component 20 and is configured to receive the converged light beams LG1', LG2', and LG3' and the mixed purge gas. The output end 702 is connected to the ignition nozzle 8 and is configured to output the converged light beams LG1', LG2', and LG3' and the mixed purge gas to the ignition nozzle 8.

[0104] For example, the input end 701 has a tapered shape to further ensure that the collected light beams LG1', LG2', and LG3' can smoothly enter the light guiding component 7. The narrow end of the tapered input end 701 is the same as the diameter of the tubular member of the light guiding component 7, which is d4, where d4>d3 (d3 is the diameter of the collected light beams, and d4 must be larger than the diameter of the collected light beams to ensure smooth entry into the optical transmission channel).

[0105] For example, the size of the ignition nozzle 8 is set to gradually decrease along the guiding direction R. Furthermore, the size of the ignition nozzle 8 at the conical nozzle should be set as follows: under the premise of not hindering light transmission, the inner diameter of the conical nozzle is as small as possible to ensure that when the mixed purified air is ejected from the output end, a purified air diffusion area T2 can be formed in the injection area of ​​the nozzle, so that the collected light beams LG1', LG2', and LG3' are transmitted to the light blocking component 40 through the purified air diffusion area T2.

[0106] For example, the ignition nozzle 8 can be a single-layer or multi-layer structure. When it is a single-layer structure, it can be made of a high-temperature resistant material. When it is a multi-layer structure, it can include a metal layer and a high-temperature resistant coating applied on the metal layer. In actual production, the latter is preferred for cost reduction.

[0107] like Figure 1 As shown, in the guiding direction R, the light blocking component 40 is located on the side of the ignition nozzle 8 away from the light guiding component 7 and is used to block all light beams emitted from the ignition nozzle 8, such as blocking all the collected light beams LG1', LG2', and LG3'.

[0108] like Figure 5As shown, for example, the light blocking member 40 is a convex quadric body 9 (e.g., a sphere). In the guiding direction R, the convex quadric body 9 is located on the side of the ignition nozzle 8 that is away from the light guiding member 7. That is, in the guiding direction R, the ignition nozzle 8 is located between the light guiding member 7 and the convex quadric body 9. This arrangement facilitates the convex quadric body 9 to block all of the converged light beams LG1', LG2', and LG3' emitted from the ignition nozzle 8.

[0109] Figure 6 FIG. 1 is a schematic diagram of the light path of the light blocking component according to an embodiment of the present invention. Figure 6 As shown, the convex quadratic body 9 has an optical reflective surface 91, which is a convex quadratic profile facing the ignition nozzle 8. The convex quadratic profile is configured to form a divergent reflection for the converged light beams LG1', LG2', and LG3' emitted from the ignition nozzle 8, thereby blocking all the light beams LG1', LG2', and LG3' emitted from the ignition nozzle 8, and completely avoiding the harmful continued propagation of the laser beam after ignition.

[0110] Herein, “divergent reflection” means that the light beam reflected by the reflecting surface is scattered away from the convex quadratic surface 9 , similar to an “umbrella cap” type distribution.

[0111] Without convex quadric body 9, the focused beams LG1', LG2', and LG3' could directly irradiate components such as the boiler wall or heat receiver, causing damage. In embodiments of the present invention, the provision of convex quadric body 9 allows for reflection or refraction of the laser beam, thereby preventing the high-energy laser beam from directly irradiating components such as the boiler wall and heat receiver. A sphere is preferably used as convex quadric body 9 in the present invention.

[0112] In the embodiment of the present invention, the "optical reflective surface" 91 refers to a smooth reflective surface with light-reflecting properties. Without the optical reflective surface 91, for example, a rough reflective surface may cause overheating and damage to the convex quadric body 9 due to excessive absorption of laser energy. This may cause the focused light beams LG1', LG2', and LG3' to directly irradiate equipment components such as boiler walls or heat receivers, thereby damaging these devices. In the embodiment of the present invention, by providing the optical reflective surface 91, the laser beam can be reflected or refracted, thereby avoiding excessive absorption of laser energy and damage to the convex quadric body 9. The present invention preferably uses the optical reflective surface 91.

[0113] like Figure 6As shown, the nozzle of the ignition nozzle 8 is directly opposite the optical reflective surface 91 of the convex quadratic body 9, and there is a set spatial distance between the two, wherein the side close to the convex quadratic body 9 is the set laser ignition space. That is, a laser ignition area SP is provided between the ignition nozzle 8 and the optical reflective surface 91. For example, a spatial distance along the guide direction R is provided between the ignition nozzle 8 and the optical reflective surface 91, and the laser ignition area SP is the area from about 1 / 2 of the spatial distance to the optical reflective surface 91. In this article, "approximately" or "about" means that process errors are allowed. Of course, it can also be narrower than the above area. For example, the laser ignition area SP can be the area from about 1 / 3 of the spatial distance to the optical reflective surface 91, because the laser ignition area SP has no clear boundary.

[0114] For example, the axis O1 of ignition nozzle 8 coincides with the diameter extension line O2 of optical reflective surface 91 passing through the sphere center. Thus, the mixed purified air ejected from the nozzle of ignition nozzle 8 can sweep out a purified air diffusion zone between ignition nozzle 8 and optical reflective surface 91, forming a relatively clean light path in the space leading to convex quadratic body 9. The converged light beams LG1', LG2', and LG3' emitted from ignition nozzle 8 propagate through purified air diffusion zone T2 with minimal light energy loss, reach convex quadratic body 9, and are reflected by optical reflective surface 91.

[0115] It should be noted that the converged light beams LG1 ′, LG2 ′, and LG3 ′ include converged laser beams (ie, three converged first light beams L1 ) and converged indicator lights (ie, three converged second light beams L2 ) transmitted along the same optical path.

[0116] like Figure 6 As shown, the converged beams LG1', LG2', and LG3' emitted from the ignition nozzle 8 pass through the purified air diffusion zone like an "umbrella handle" surface. When the pulverized coal boiler is supplied with air and the pulverized coal is ignited, the laser beams in this area can directly collide and intersect with the incoming air and pulverized coal jets, thereby achieving primary ignition. Simultaneously, the converged laser beams are reflected by the reflective surface 91, scattering away from the convex quadratic surface 9 in a distribution pattern resembling an "umbrella cap" (hereinafter referred to as "narrowly expanded reflected laser beams"). This has the following benefits:

[0117] On the one hand, the narrow beam reflected laser diverges rapidly, and the energy density of the "remote" laser is greatly reduced at a distance of about 300 mm from the optical reflective surface 91, which is completely insufficient to cause laser damage, ensuring the absolute safety of any equipment components such as the boiler wall and the heat receiver. At the same time, the "remote" laser also helps to increase the initial temperature of the furnace space.

[0118] Secondly, the narrow beam expansion reflected laser diverges rapidly, and at a "mid-range" distance of about 300 mm from the optical reflective surface 91, the laser still has a high energy density, which can significantly increase the ambient temperature in and around the set laser ignition area, even reaching the ignition temperature of coal powder. The resulting local high temperature is conducive to ignition.

[0119] Thirdly, the narrow beam expansion reflected laser diverges rapidly, and the "short-range" laser energy density within about 200 mm from the optical reflective surface 91 is higher, and the laser "umbrella cap" formed collides and intersects with the wind and coal powder jet. Because the concentrated laser beam at the "umbrella handle" has directly achieved a collision and intersection with the wind and coal powder before being reflected by the convex quadratic surface body 9, the narrow beam expansion reflected laser beam at the "umbrella cap" has achieved a second collision and intersection with the wind and coal powder. This double collision and intersection effect further increases the action space of the laser and the wind and coal powder jet, increases the ignition volume, and improves the safety, reliability and effectiveness of ignition. Compared with traditional gas and oil methods, the laser beam ignition method of the present application is safer, more economical and more stable.

[0120] In addition, in the present application, since the converged second light beam L2 and the converged first light beam L1 are transmitted along the same optical path and are used as indicator light, before formal ignition, the transmission path of the first light beam L1 can be understood through the second light beam L2 to perform a "pre-ignition" test.

[0121] For example, when the converged first light beam L1 is reflected into an "umbrella cap" shape, the converged second light beam L2 is also reflected into an "umbrella cap" shape, thereby indicating the approximate location of the set ignition space. When officially ignited, the continuously delivered high-density laser light has an "umbrella handle" shape, which continuously acts on the wind and coal powder jets, safely and reliably triggering continuous fire. The reflected "umbrella cap"-shaped laser light continuously supports and stabilizes combustion. For example, when the ignition device is used in conjunction with a swirl burner, the strong rotation of the torch caused by the swirling jet and the strong mixed disturbance of the wind and coal powder jets can be used to further achieve the effects of supporting and stabilizing combustion.

[0122] For example, the diameter of the convex quadratic body 9 is d5, where d5>N*d3, where N>1, and the specific value of N is determined by actual needs, but should not be too large to minimize the disturbance to the wind and coal powder jet.

[0123] For example, the convex quadratic body 9 is made of a high-temperature resistant material to prevent the laser from causing penetrating damage thereto.

[0124] For example, the convex quadratic surface body 9 can not only block the laser, but also accumulate laser energy and "additional heat source" due to being irradiated by the laser, which is more conducive to ignition. In addition, the damping of its convex quadratic surface can also play a role in locally stabilizing the flame.

[0125] While the light-blocking component described in this embodiment of the present invention utilizes a convex quadric surface 9 as an example, it is understood that other light-blocking components may be used in other embodiments, such as a hemisphere, a hemisphere combined with a cylinder, a hemisphere combined with a cone, or an aspheric shape. Considering the primary purpose of achieving the multiple functions of blocking, reflecting / refracting, and accumulating laser energy during air supply and before and after coal ignition, and particularly the need to ensure boiler equipment safety, a sphere is preferred. The convex quadric surface 9 may be solid or hollow, and this is not limited in this embodiment of the present invention, as long as it can reflect the concentrated light beam projected onto its surface.

[0126] Figure 7 FIG. 1 is another light path diagram of the light blocking component according to an embodiment of the present invention. Figure 7 As shown, when the axis line O1 of the ignition nozzle 8 does not coincide with the diameter extension line O2 of the optical reflective surface 91 passing through the sphere center, the converged laser beam can also be reflected by the optical reflective surface 91. After reflection, the converged laser beam can also form an "umbrella cap" shape.

[0127] Figure 7 In the embodiment, by setting the nozzle of the ignition nozzle 8 to face the upper right direction and obliquely toward the lower part of the optical reflective surface 91 of the convex quadratic curved surface 9, a certain inclination angle is provided between the axis line O1 of the ignition nozzle 8 and the diameter extension line O2 of the optical reflective surface 91 passing through the center of the sphere, the purposes of ignition, combustion assistance and stable combustion can also be achieved.

[0128] It is understood that in the embodiment of the present invention, multiple convergent laser beams can be distributed and arranged in an upward and downward staggered manner to respectively project to different parts of the optical reflective surface 91. Figure 7 On this basis, the same ignition nozzle 8 can also be set on the upper part of the optical reflective surface 91, that is, the nozzle of the ignition nozzle 8 is set to face the upper part of the optical reflective surface 91 of the convex quadratic surface body 9 in an oblique direction toward the lower right, thereby increasing the range of the ignition, combustion-supporting and stable combustion space.

[0129] like Figure 1 As shown, in order to place the light blocking component 40 at an appropriate position in the furnace space without involving any modification of the boiler and the burner, the laser ignition device 100 may further include a fixing component 50. Figure 5 As shown, for example, fixing member 50 includes a connector 10 connected to convex quadric body 9 for securing and supporting convex quadric body 9. One end of connector 10 is connected to convex quadric body 9, and the other end is connected to either ignition nozzle 8 or light guide member 7, for example, ignition nozzle 8. The provision of connector 10 renders the laser ignition device a self-contained entity, avoiding unnecessary connections with the original boiler system and minimizing contact with the boiler itself, resulting in a safer and simpler design.

[0130] It should be noted that regardless of how convex quadratic body 9 is attached and fixed, it is positioned at a suitable distance from the nozzle opening of ignition nozzle 8, with optical reflective surface 91 always oriented toward the nozzle opening. This ensures that the space between convex quadratic body 9 and the nozzle opening of ignition nozzle 8 forms the laser ignition zone, achieving ignition, combustion support, and stable combustion. It is understandable that, because there is no clear boundary between the pulverized coal and the air jet, the laser ignition zone also lacks a clear boundary or morphology.

[0131] For example, the connector 10 is made of a metal material coated with a heat-insulating coating, or made of a high-temperature resistant material. The connector 10 can be tubular or plate-shaped, and has a certain mechanical rigidity.

[0132] For example, the connector 10 or the convex quadratic body 9 may have through-holes, threaded openings, screw threads, or bayonet holes for connection and fixation, thereby achieving simple and easy connection. For example, the convex quadratic body 9 may have an auxiliary through-hole that extends through the diameter, or two symmetrical auxiliary blind holes that do not extend through the diameter but are located at opposite ends of the diameter, or a single auxiliary blind hole located at one end of the diameter, for insertion of the connector 10. The diameters of the auxiliary through-holes and auxiliary blind holes, as well as the depth of the blind holes, are determined by actual needs.

[0133] For example, the optically reflective surface 91 can be a highly reflective, smooth convex quadratic surface located on the side of the convex quadratic body 9 facing the ignition nozzle 8, or it can be a partially reflective convex quadratic surface. The portion of the convex quadratic body 9 facing away from the ignition nozzle 8 can be a reflective surface or a non-reflective surface, an optically reflective surface or a roughened reflective surface, and this is not limited in this embodiment of the present invention.

[0134] An embodiment of the present invention further provides a thermal combustion device, which includes a burner and the laser ignition device described in any of the above embodiments.

[0135] Figure 8 FIG. 1 is a schematic diagram of the structure of a thermal combustion device according to an embodiment of the present invention. Figure 8 As shown, the thermal combustion equipment is, for example, a pulverized coal boiler, which includes the laser ignition device 100 and the burner 200 of any of the above embodiments.

[0136] Generally, it is well known that high-power pulverized coal boilers use burners 200 of different jet types, which will produce wind and pulverized coal jets with different structures and morphologies, and their aerodynamic characteristics (velocity distribution, range, entrainment characteristics and recirculation zone, etc.) are different, and the ignition mechanism is completely different.

[0137] For example, the burner 200 can be divided into two types: a swirl burner and a direct current burner:

[0138] The aerodynamic characteristics of the swirl burner are that the rotating secondary air in the outer circle wraps the rotating or non-rotating primary air and pulverized coal jet in the inner circle. The high-temperature flue gas sucked in the outer recirculation zone formed only heats the secondary air itself, and cannot ignite due to the low pulverized coal concentration; the role of the inner recirculation zone is different. The sucked high-temperature flue gas heats the primary air and pulverized coal jet. Because there is sufficient pulverized coal concentration, it can ignite as long as the temperature is high enough. With the help of the strongly rotating torch and the mixed disturbance of the airflow and pulverized coal, the combustion develops rapidly. The ignition mechanism is "from inside to outside". The combustion starts in the inner recirculation zone of the rotating jet and then develops outward.

[0139] The aerodynamic characteristics of the DC burner are that the primary air and pulverized coal jets are not wrapped with the secondary air. The jets rely on the suction effect of their outer boundaries to draw in high-temperature flue gas and receive heat from adjacent flames to heat themselves. Also, due to the low concentration of pulverized coal, the secondary air cannot ignite a real fire after being heated. Instead, the ignition starts from the outer boundary of the primary air and pulverized coal jets, and then quickly develops to the central area. The ignition mechanism is "from outside to inside". Combustion starts from the outer boundary of the primary air and pulverized coal DC jets and then develops inward.

[0140] When a pulverized coal boiler utilizes a swirl jet burner, based on its "inside-out" ignition mechanism, the laser ignition device 100's light guide component 7 is located within the horizontal portion of the primary air and pulverized coal conveying pipeline, nested coaxially and isolated from each other. This light guide component concentrates the laser beam, the indicator light, and the mixed purified air within this semi-enclosed section of the pipeline, isolated from the air and pulverized coal conveying, and conveys them coaxially to the nozzle of the connected ignition nozzle 8. The ignition nozzle 8 extends approximately D1 beyond the damping device (flame stabilization device) of the primary air and pulverized coal conveying pipeline, with D1 being ≥ 10 mm.

[0141] When a DC jet burner is used, based on its "outside-to-inside" ignition mechanism, as well as the characteristics of multi-nozzle combined delivery of primary air and coal powder, and equal or graded air distribution of secondary and tertiary air, the light guide component 7 of the laser ignition device 100 is set at the position of the original main ignition oil (gas) gun, and the ignition nozzle 8 connected to it extends out of the original damping device (flame stabilization device) by approximately a distance D2, with D1 ≥ 10 mm, and multiple laser ignition points can be set according to the position distribution of the original main ignition oil (gas) gun.

[0142] In summary, for burners of different jet types, the direction, position (or area) of laser ignition, power adjustment of each laser beam, opening timing control, etc. need to be set according to different ignition mechanisms. However, it can be determined that whether it is a swirl burner suitable for high-volatile and high-calorie coal, or a direct current burner suitable for low-volatile and low-calorie coal, the laser ignition device 100 of the present invention can be used.

[0143] In the embodiment of the present invention, the convex quadratic body 9 has the following multiple functions:

[0144] 1. Before air supply and pulverized coal ignition, after the laser is turned on, it plays the role of blocking the continued transmission of the laser at the set spatial position, reliably preventing the high-energy laser beam from directly irradiating the boiler wall, heat receiver and other equipment components, and completely eliminating the possibility of high-density laser energy damaging the boiler equipment and causing major safety accidents.

[0145] 2. It also plays the role of accumulating laser energy, converting part of the laser energy into heat energy and accumulating it in the sphere, making the sphere a "thermal energy source" that is more conducive to ignition, combustion support and stable combustion.

[0146] 3. By adjusting the relative spatial position relationship between the sphere and the nozzle, the laser and the indicator light are irradiated to different positions of the optical mirror hemisphere, producing different optical effects such as beam expansion reflection and beam expansion refraction, so that the laser ignition system provided by the present invention is suitable for swirl and DC jet type burners.

[0147] 4. Before air supply and coal powder ignition, turn on the indicator light to block the continued transmission of the indicator light in the set space, display the light transmission path between the nozzle and the sphere, and simultaneously display the red or color indicator light spot irradiated on part of the spherical surface, accurately visualize the set laser ignition space position, and appropriately adjust the relative spatial relationship between the nozzle and the sphere according to actual needs on site, thereby improving the convenience, safety and reliability of the ignition operation.

[0148] 5. After the air is supplied and the coal powder is ignited, the sphere damps the wind and coal powder jets and the mixed purified air, which stabilizes the flame locally and shapes the "root flame", effectively assisting and stabilizing combustion.

[0149] 6. During the combustion process, the sphere continues to block the high-energy laser, continues to store heat energy and scatter laser energy, and continues to serve as a "thermal energy source" to support and stabilize combustion.

[0150] It is particularly noted that high-energy-density lasers and high temperatures can also photoionize and thermally ionize, inducing the production of a large number of active particles, increasing the kinetic activity and effective collision frequency of oxide and combustion molecules, and playing an important role in promoting ignition and combustion development.

[0151] In addition, high-density laser energy, thermal energy and combustion heat are an intertwined, coupled, interacting and mutually reinforcing thermodynamic process. Due to the inaccuracy and dynamic change characteristics of laser scattering, thermal energy convection, and wind and fuel transport flow fields, the laser ignition area does not have a strictly determined morphology, volume and boundary in the physical sense. However, it is scientifically appropriate to describe it as the approximate ignition area where the laser beam directly collides and intersects with the wind and coal powder jet, or scatters or refracts and then collides and intersects with the wind and coal powder jet.

[0152] To facilitate understanding of the laser ignition device provided by the present invention, an example of an ignition method of the laser ignition device is provided below. It should be understood that the following example is not intended to limit the present invention.

[0153] For example, when the laser ignition device 100 is used together with a rotating jet burner, the laser ignition device 100 may be configured as follows:

[0154] 1. Seven infrared laser sources are used, each with an output laser power of 3 kW. The total laser ignition power reaches 21 kW, which is about 30% greater than the rated ignition power of the thermal power unit. The large redundant ignition laser energy, combined with the parallel application of seven independent working devices, ensures high safety and reliability of ignition and avoids the risk of major safety accidents caused by ignition failure. The lasers are arranged in a circle with one beam in the center and six beams on the periphery, equally divided on the same axis.

[0155] 2. Accordingly, 7 optical collimation components are set to collimate the lasers output by the 7 infrared laser sources into 7 collimated laser beams, with diameters d1 = 10 mm ± 1 mm and D1 = 3 m; 7 red light sources are set to transmit along the same optical path as the collimated laser beams; 7 air purification paths G are set.

[0156] 3. Set up 7 phosgene combination components 3, d2 = 15 mm, straight-through opening, respectively combine a collimated laser beam with a red light beam in the same optical path and a path of purified air G into a tubular part with a diameter of d2 = 15 mm and a length of about 36 mm, and output them to the straight-through output port.

[0157] 4. An optical transmission component 20 is provided, having seven input ports and one output port. The seven input ports are respectively connected to seven phosgene combination components 3. A geometric optical beam combining method is used to combine seven collimated laser beams and a red light beam on the same optical path into a concentrated laser beam with a diameter of d3 and a concentrated indicator light on the same optical path. d3 is approximately 28 mm. The seven laser beams (including the indicator light on the same optical path) are spatially positioned with a central beam and six equally divided beams on the periphery. The seven paths of purified air G are mixed into one path of mixed purified air. The concentrated beams and the mixed purified gas are output from the output port.

[0158] 5. The output port of the optical transmission component 20 is connected to the input port of the optical guide component 7. The optical guide component 7 is arranged at the axis of the burner primary air and coal powder conveying pipeline, and guides and conveys the collected laser beam, collected indicator light, and mixed purified air to a distance of about 5600 cm. Two supporting members are arranged in the middle to support the optical guide component 7.

[0159] 6. The output port of the light guide component 7 is connected to the ignition nozzle 8, which ignites and emits a concentrated laser beam and a concentrated indicator light along the same optical path, and sprays out the mixed purified air.

[0160] 7. The convex quadratic surface 9 is connected to and fixed on the ignition nozzle 8. The diameter of the sphere is 96 mm. The optical reflective surface 91 is opposite to the ignition nozzle nozzle, with a distance of about 260 mm, and is roughly located in front of the set recirculation zone of the burner; the mixed purified air is ejected from the nozzle, blowing the 260 mm interval into a relatively clean compressed air diffusion zone; the axis O1 of the ignition nozzle 8 coincides with the extension line O2 of the diameter of the sphere, forming a beam expansion reflection; the wind and coal powder jets collide and intersect at a distance of approximately 200-260 mm from the optical reflective surface to achieve ignition, the beam expansion reflected light energy assists combustion, and the local static pressure zone formed by the sphere generates a "root flame" to cooperate with the recirculation zone mouth for stable combustion, thereby promoting the normal development of combustion.

[0161] The embodiment of the present invention further provides an ignition method of a laser ignition device. For example, the ignition method of the laser ignition device 100 includes:

[0162] Step 1: Provide infrared laser;

[0163] Step 2: transmitting the infrared laser to the ignition nozzle and causing it to be emitted from the ignition nozzle for ignition;

[0164] Step 3: Block all infrared laser light emitted from the ignition nozzle.

[0165] Compared to traditional ignition methods using fuel oil, gas, and plasma technologies, the ignition method provided by the above-mentioned embodiment of the present invention uses a laser as the ignition energy beam. This method is not only time-efficient and energy-efficient, but also highly safe and unrestricted by the type of combustible material. Furthermore, because laser energy provides a sustainable supply and does not deplete after a period of use like fuel oil and gas, the laser ignition device of the embodiment of the present invention also assists and stabilizes combustion. Furthermore, the ignition device of the embodiment of the present invention includes a light-blocking component that prevents the laser from striking the inner walls of the thermal combustion equipment, making the operation safer, more convenient, and more economical, and possessing broad application prospects.

[0166] To facilitate understanding of the laser ignition device provided by the present invention, an example of an ignition method of the laser ignition device is provided below. It should be understood that the following example is not intended to limit the present invention.

[0167] For example, the ignition method of the laser ignition device 100 includes the following steps:

[0168] 1) Turn on one or more infrared laser sources (i.e., first light source 1) and emit laser light (i.e., first beam L1) with a set power, beam quality, and spatial arrangement;

[0169] 2) Optionally, the laser light emitted by the infrared laser source is optically shaped and transformed by the collimating component 2 to output a collimated laser beam;

[0170] 3) Optionally, turning on the visible light source (i.e., the second light source 4) to emit red or green light (i.e., the second light beam L2) serving as an indicator light, wherein the indicator light is transmitted along the same optical path as the collimated laser beam;

[0171] 4) Optionally, the purified air generating device (i.e., the air supply component 5) is turned on to provide purified air G according to the set pressure, flow rate, dust content level, and water content percentage;

[0172] 5) Optionally, the collimated laser beam, the indicator light, and the purified air G are combined into a tubular member with a diameter of d2 using the phosgene assembly component 3, and are coaxially transported in the tubular member in a semi-sealed state and output to the optical transmission component 20;

[0173] 6) The optical transmission component 20 is used to combine the multiple collimated laser beams and the indicator light transmitted along the same optical path into a combined laser beam with a diameter of d3 and a combined indicator light along the same optical path. The multiple paths of purified air G are mixed into one path of mixed purified air and output to the light guiding component 7;

[0174] 7) Using the light guide component 7 to guide the concentrated laser beam and the concentrated indicator light on the same optical path, mixed and purified air to the ignition nozzle 8;

[0175] 8) The concentrated laser beam, the concentrated indicator light on the same optical path, and the mixed purified air are accurately guided to the set spatial position through the ignition nozzle 8, and ejected and emitted from the nozzle;

[0176] 9) The mixed purified air is ejected from the nozzle, sweeping out a relatively clean compressed air diffusion area. The focused laser beam and the focused indicator light on the same optical path pass through this area and are reflected by the convex quadratic surface 9, forming a narrow or wide beam expansion reflection or refraction, and accumulating part of the laser energy and heat energy.

[0177] 10) Turn on the air supply and coal powder, the narrow or wide beam expansion reflected laser "umbrella cap" and high temperature first heat the air and coal powder jets, and then the laser beam "umbrella handle" is concentrated to directly collide and intersect with the wind and coal powder jets at the tail of the purified air diffusion zone. The high energy density laser and high temperature ignite the coal powder, and the forward and backward scattering is reflected by the narrow or wide beam expansion to form a small open "umbrella cap" to assist and stabilize combustion. The convex quadratic surface body 9 plays a local combustion stabilizing role, and forms a "root flame" in the recirculation zone at the rear of the sphere to further stabilize the combustion, so that the combustion develops normally. Depending on the combustion development situation, the laser combustion assistance and stabilization can be continued, or the laser power can be reduced beam by beam until all the ignition lasers, indicator lights, and air purification are turned off to successfully complete an ignition process.

[0178] In this embodiment of the present invention, the indicator light serves as a "pre-ignition" system for the entire process and scenario. The indicator light allows for observation of the on-site conditions, and fine-tuning can be performed as needed. For example, the outer lasers are activated one by one, with output power controlled at approximately 5%, gradually increased to rated power, and the on-site conditions are observed. The decision to initiate ignition is based on the actual situation. After confirming that ignition is possible, air and pulverized coal are supplied at the pulverizer's minimum load, and the central laser is activated to observe the ignition status. If combustion develops normally, the air supply and pulverized coal volume are gradually increased, and the ignition laser energy can be further increased as needed. Once combustion stabilizes, the lasers and indicator light are turned off, and the air is purified.

[0179] To facilitate understanding of the laser ignition device provided by the present invention, specific examples of the laser ignition device and the ignition method are provided below. It should be understood that the following examples are not intended to limit the present invention.

[0180] The laser ignition device, thermal combustion equipment, or laser ignition method provided by the above-mentioned embodiments of the present invention utilizes laser as an ignition medium and has the following advantages:

[0181] First, laser is the energy beam with the highest energy (power) density that can be achieved in engineering so far. It can easily reach a power density of 107W / cm2 and above, or an energy density of 107J / cm2 / s and above, generating high temperatures of thousands of degrees, which is much higher than the ignition temperature of about 600℃ of coal powder or even extremely lean coal powder. It can ignite all combustible materials, ensure ignition in terms of energy and temperature, maximize the safety and reliability of ignition, combustion support and stable combustion, and completely eliminate the risk of major safety hazards caused by ignition errors or failures.

[0182] Second, it is easy to increase the ignition laser energy, easy to set the ignition zone position as needed, and easy to finely control the ignition, combustion-supporting, and stable combustion processes. It can quickly complete the entire process of ignition, combustion-supporting, and stable combustion with the maximum dT / dt and dP / dt gradients that the thermoelectric system can withstand, thereby solving the key bottleneck problem of safely and reliably achieving "10%-100% deep peak regulation" and laying a solid technical foundation for revolutionary progress in thermoelectric technology.

[0183] Third, laser is a flexible high-energy beam that is easy to interface with existing thermoelectric systems. It requires less engineering modification and is less expensive. Laser ignition, combustion assistance, and enhanced combustion stability are more environmentally friendly and economical.

[0184] Fourth, a "pre-ignition" method is provided before the actual ignition. The indicator light clearly shows the laser transmission path and the ignition space position, and the laser ignition process is visualized in advance in a panoramic view throughout the entire process, thereby improving the safety, reliability and convenience of the actual ignition operation.

[0185] In this article, there are several points to note:

[0186] (1) The drawings of the embodiments of the present invention only relate to the structures related to the embodiments of the present invention. Other structures may refer to conventional designs.

[0187] (2) In the absence of conflict, the embodiments of the present invention and the features therein may be combined with each other to form new embodiments.

[0188] (3) The above description is merely an exemplary embodiment of the present invention and is not intended to limit the scope of the present invention. The scope of the present invention is determined by the appended claims.

[0189] Finally, it should be noted that the above embodiments and drawings are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A laser ignition device for thermal combustion, comprising: a light generating assembly, a light transmitting assembly, an ignition assembly, and a light blocking assembly, wherein: The light generating assembly includes a first light source configured to emit a first light beam, the first light beam being a laser; The light transmitting component is configured to transmit the first light beam to the ignition assembly; The ignition assembly includes a light guiding component and an ignition nozzle located at a distal end of the light guiding component, wherein the light guiding component is configured to guide the first light beam in a guiding direction to be emitted through the ignition nozzle for ignition; In the guiding direction, the light blocking member is located on a side of the ignition nozzle away from the light guiding member and is configured to block the entire first light beam emitted from the ignition nozzle. The light blocking component is a convex quadratic surface, which is located on the side of the ignition nozzle away from the light guiding component in the guiding direction; the convex quadratic surface has an optical reflective surface, which is configured to form a divergent reflection on all light beams emitted from the ignition nozzle; the divergent reflection refers to the light beams reflected by the optical reflective surface being scattered in a direction away from the convex quadratic surface. The size of the ignition nozzle is set to gradually decrease along the guide direction and have a tapered nozzle, that is, a tapered laser output port. The optical reflective surface is a highly reflective smooth convex quadratic surface located on the side of the convex quadratic body facing the ignition nozzle; a laser ignition area is provided between the ignition nozzle and the optical reflective surface; a spatial distance along the guiding direction is provided between the ignition nozzle and the optical reflective surface, and the laser ignition area is the area from 1 / 2 of the spatial distance to the optical reflective surface.

2. The laser ignition device for thermal combustion according to claim 1, wherein: The light generating assembly further comprises: a gas supply component configured to provide a purge gas to the first light beam; The light transmission component is further configured to transmit the purge gas and the first light beam along a same optical path to the ignition assembly and emit from the ignition nozzle.

3. The laser ignition device for thermal combustion according to claim 2, wherein: The light generating assembly further comprises: The phosgene combining component is configured to receive and combine the first light beam and the purge gas, and transmit the combined first light beam and the purge gas to the light transmitting component.

4. The laser ignition device for thermal combustion according to claim 1, wherein: The light generating assembly further comprises: a collimating component configured to collimate the first light beam; a second light source configured to emit a second light beam, wherein the second light beam is visible light and is used as an indicator light; The second light beam is configured to be transmitted along the same optical path as the collimated first light beam through the light generating assembly, the light transmitting component, and the light guiding component to the ignition nozzle and to be emitted from the ignition nozzle.

5. The laser ignition device for thermal combustion according to claim 4, wherein: The light generating assembly further comprises: a gas supply component configured to provide a purge gas to the first light beam; The phosgene combination component is configured to receive and combine the collimated first light beam, the second light beam, and the purge gas, and transmit the combined collimated first light beam, the second light beam, and the purge gas to the light transmission component.

6. The laser ignition device for thermal combustion according to claim 5, wherein: The phosgene assembly component includes: a first input port, a second input port and an output port; The first input port is configured to receive the collimated first light beam and the second light beam; The second input port is configured to receive the purge gas; The output port is configured to output the collected collimated first light beam, the second light beam, and the purge gas to the light transmission component.

7. The laser ignition device for thermal combustion according to claim 5, wherein: There are multiple light generating components, multiple first light sources emit multiple first light beams, multiple second light sources emit multiple second light beams, and multiple gas supply components provide multiple paths of purified gas; The light transmission component is configured to collect the plurality of first light beams and the plurality of second light beams to form a collected light beam, and transmit the collected light beam to the ignition assembly so that the collected light beam is emitted from the ignition nozzle; The light transmission component is further configured to mix the multiple purge gases to form a mixed purge gas and transmit the mixed purge gas to the ignition assembly so that the mixed purge gas is ejected from the ignition nozzle.

8. The laser ignition device for thermal combustion according to claim 7, wherein: The mixed purge gas forms a purge gas diffusion zone in the injection area of ​​the ignition nozzle, and the converged light beam is transmitted to the light blocking component through the purge gas diffusion zone.

9. The laser ignition device for thermal combustion according to any one of claims 1 to 8, wherein: The first light source is an infrared laser source, and the laser is an infrared laser.

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