RU2788490C1 - Device and method for burning fuel-air mixture - Google Patents

Abstract

FIELD: electrical engineering.

SUBSTANCE: device for burning the fuel-air mixture can be used in the fuel industry and energy industry and belongs to the field of electrical engineering, namely to ignition devices designed for burning of fuel-air mixtures, for example, coal dust-air mixture during oil-free ignition of CHP boilers. The device for burning the fuel-air mixture contains an insulating housing with an air supply line, inside which an electrode system and voltage supply lines are installed, and the electrode system has an initiating part, made adjustable and attached to the housing from inside it, and a removable part extending beyond the housing connected to each other. The housing is collapsible and made of fiberglass. The housing has an observation window. The voltage supply line contains at least one bus connected to any of the electrodes. The initiating part of the electrode system has breakdown voltage regulators. The breakdown voltage regulators are made in the form of movable screws.

EFFECT: formation of a stable gas diffusion discharge and, as a result, effective ignition of the fuel-air mixture, as well as an increase in maintainability and wear resistance of the electrode system.

11 cl, 4 dwg

Description

Technical field

[1] The claimed invention can be used in the fuel industry and energy and relates to the field of electrical engineering, namely, to ignition devices designed to ignite air-fuel mixtures, for example, to ignite a coal dust-air mixture during oil-free ignition of CHP boilers.

State of the art

[2] The ignition device, or igniter, is a device that ignites the main burner, which ignites the air-fuel mixture supplied to the combustion devices and thermal equipment. This device is usually a channel with electrodes placed inside it. When voltage is applied to them, an electric discharge occurs in the breakdown area, which, when moving along the electrodes, ignites the fuel particles in the burner. The movement of the discharge can be carried out by supplying air in the channel or by the action of a magnetic field. There are several devices and methods that describe the different designs of igniters and methods of combustion of the air-fuel mixture.

[3] A solution is known (RU 2726023 C1; publ. 07/08/2020; IPC: F23D 1/00, F23Q 13/00), which discloses a method for flaring combustion of an air-fuel mixture, including, among other things, the creation of an electric discharge in the ignition zone, the supply fuel and air into the ignition zone, the implementation of plasma electroionization ignition of the fuel-air mixture and the implementation of its flare combustion, while the electric discharge is affected by a magnetic field, the lines of force of which are oriented perpendicular to the flow of the air-fuel mixture.

[4] In this solution, a device for plasma electroionization ignition of an air-fuel mixture is also disclosed, comprising a housing to which a fuel line and an air duct are connected, rod electrodes are installed inside the housing, directed along its longitudinal axis and designed to generate an electric discharge, and the housing is made of non-magnetic material, behind the rod electrodes, in the direction of the air-fuel mixture flow, on the outer opposite sides of the housing, electromagnetic coils with magnetic circuits are installed, with the possibility of moving along the longitudinal axis of the housing, and the longitudinal axes of these electromagnetic coils with magnetic circuits are coaxial to each other and perpendicular to the longitudinal axis of the housing, and the electromagnetic coils with magnetic circuits are installed opposite the electric discharge radiation zone inside the housing.

[5] The disadvantages of this method and device include the location of the electrodes in the air-fuel mixture, leading to accelerated abrasive wear of these elements, as well as difficult control of the ignition of the electric arc between the electrodes.

[6] Another solution is known (US 4241673 A; publ. 12/30/1980; IPC: F23D 1/00), consisting of, among other things, the formation of a flammable mixture, including the presence of a source of pulverized coal dust with a sufficiently small particle size and the supply of pulverized coal mixture, transmission flammable mixture into the ignition zone, supplying ignition energy to the mixture with its subsequent ignition, checking the success of ignition and flame stabilization. The device for igniting and maintaining combustion of the pulverized coal mixture, in turn, contains a device for forming the mixture, a device for supplying it to the ignition zone, devices for maintaining combustion, and sensors that respond to particle ignition.

[7] Among the disadvantages of the above device and method is the difficult replacement of the ignition electrode.

[8] Another solution close to the claimed invention can be considered (RU No. 2410603 C1; publ. 27.01.2011; IPC: F23Q 5/00, F23Q 13/00). The patent describes a device for plasma ignition of pulverized coal, containing a housing, rod electrodes for generating an electric arc, a fuel line and a secondary air pipeline, characterized in that the housing is divided by a transverse partition into resonant and cooling chambers, and in the center of the partition a passage of secondary air is made and in it rod electrodes are installed with the possibility of longitudinal movement, and their working part is directed inside the resonant chamber, and the electric arc is created by high-frequency alternating current in the resonant chamber with the formation of an acoustic field.

[9] The disadvantages of this invention are that the presence of the electrodes in the flow of pulverized coal mixture reduces the service life of the electrodes subjected to abrasive wear. In addition, the regulation of the breakdown distance is difficult due to the design of the electrodes.

[10] The disadvantage of all the mentioned devices is the difficult replacement of the ignition electrodes, as well as the lack of a simple regulation of the breakdown distance between them.

The essence of the invention

[11] The objective of the present invention is to provide a collapsible and efficient combustion device for air-fuel mixture and to develop a method that maintains the claimed efficiency of the device.

[12] This problem is solved by achieving the technical result claimed by the invention, which consists in the formation of a stable gas diffusion discharge and, as a result, the effective ignition of the air-fuel mixture, as well as increased maintainability and wear resistance of the electrode system.

[13] Stability is achieved through the presence of a removable part of the electrode system that extends beyond the housing and does not come into contact with the air-fuel mixture flow, which eliminates abrasive wear of the electrode system and thereby contributes to stable discharge ignition. In addition, stability is achieved by adjusting the breakdown distance with the help of the initiating adjustable part of the electrode system, the possibility of replacing the removable part of the electrode system and the tightness of the electrode block, as well as the possibility of installing a viewing window that provides visual control of wear of working elements, the process of ignition of the air-fuel mixture and setting breakdown distance.

[14] The technical result is achieved due to the design of the air-fuel mixture combustion device, which ensures the reliability of ignition of the gaseous diffusion discharge, increased maintainability and wear resistance of the electrode system.

[15] The air-fuel mixture combustion device comprises an insulating housing, to which an air supply line is connected, passing through the housing. The electrode system, consisting of the initiating regulated and removable parts interconnected, is placed in the housing in such a way that the initiating regulated part is installed inside the housing using fasteners, and the removable part is taken out of it. The voltage supply to the electrode system is carried out using a voltage source and a supply line connected to it, passing through the housing. The design features include the adjustable initiating part of the electrode system, which improves the control of the discharge ignition process, as well as the presence of a removable part of the electrode system, which makes it easier to replace wear parts of the system, for example, electrodes, and the removable part that extends beyond the housing, which also simplifies replacement and eliminates abrasive wear of parts of the electrode system due to the absence of their contact with the air-fuel mixture.

[16] The insulating housing performs primarily a protective function. Insulation is necessary for the breakdown to take place in the electrode system, although there are solutions where the body of the igniters itself acts as one of the breakdown electrodes. The implementation of the housing with insulation eliminates the possible danger of injury associated with the impact of electric current, and also prevents additional heating of the housing associated with the flow of current through it. To improve the maintainability of the device, the housing can be made collapsible. One of the preferred options for the body material is fiberglass. This material is a laminated sheet composite consisting of many layers of glass fabric impregnated with a polymeric thermosetting resin and pressed under high pressure. This substance has good thermal stability, high resistivity and strength. Also, a viewing window can be made in the case, with the help of which it is possible to improve the control of the process of setting the breakdown distance in the initiating part of the electrode system and, consequently, the process of discharge ignition itself.

[17] The air supply line performs two functions: moving the electric discharge inside the electrode system outside the housing and cooling the working elements of the electrode system. The supply line may communicate with the body through a fitting or other suitable detachable element.

[18] The electrode system is the main working element of the device. A voltage of sufficient magnitude, applied to it through the voltage supply lines using a voltage source, causes a breakdown of air in the system and the ignition of a discharge. The breakdown voltage depends on several parameters, including the length of the breakdown distance in the system, temperature and environment, air flow rate, and others. The electrode system is divided into two connected components: initiating and removable. The initiating part provides a fixed fixation of the electrode system in the housing with the help of fasteners and ignition of the discharge in the system, while the discharge moves along the removable part as a result of the movement of the air flow supplied through the air supply line. The removable part is connected to the initiating part, for example, using a threaded connection, and goes outside the body. If this part wears out during the operation of the device, it can be easily detached and replaced with a new one. The initiating part can be equipped with breakdown voltage regulators, with the help of which the control of the discharge ignition process and its movement along the electrode system is improved, or the breakdown distance can be adjusted by adjusting the fastenings to the case or in another way. A preferred option for regulating the initiating part is the presence of breakdown voltage regulators in it and, in particular, their manufacture in the form of screwed screws screwed into through threaded holes in the initiating part of the electrode system. This makes it easy to adjust the breakdown distance and replace the screws themselves, which improves the maintainability of the device and contributes to the stability of the discharge ignition.

[19] Voltage supply lines are used to transfer voltage from the source to the electrode system. They are made in the form of high-voltage wires and can be connected to the system either through connectors installed in the housing, or directly or in another way. Also, tires can be installed in the case, which serve to fix the wires inside the case and exclude their contact with parts of the case or between themselves, thereby ensuring stable operation of the device.

[20] The air-fuel mixture combustion method consists of several stages, in which the necessary breakdown distance is set on the combustion device using an adjustable initiating part, then the combustion device is connected to the line in which the air-fuel mixture is transferred. The connection is carried out in such a way as to ensure that the removable part of the electrode system extending beyond the housing does not come into contact with the mixture flow, but the electric discharge displaced by the air flow is within the reach of the air-fuel mixture. Next, air is supplied through the air supply line, then a gas diffusion discharge is created inside the electrode system by supplying high-voltage voltage to it through the voltage supply lines, which is then displaced by an air flow that ensures the interaction of the discharge and the fuel air mixture with its subsequent ignition and combustion. They can also carry out additional adjustment of the breakdown distance depending on various parameters of the system, for example, the temperature of the supplied air flow and its speed, which additionally contributes to the stability of the discharge ignition. The air-fuel fuel can be a dust-air mixture with a different content of components, used, for example, to ignite furnace spaces.

Description of drawings

[21] The subject matter of this application is described point by point and clearly stated in the claims. The objects, features and advantages of the invention mentioned above will be apparent from the following detailed description, taken in conjunction with the accompanying drawings, which show:

[22] FIG. 1 shows a longitudinal section of the device

[23] FIG. 2 shows a cross section of the device

[24] FIG. 3 shows a general view of the air-fuel mixture combustion device

[25] FIG. 4 is a flowchart illustrating the air-fuel mixture combustion method.

Detailed description of the invention

[26] In the following detailed description of the implementation of the invention, numerous implementation details are provided to provide a clear understanding of the present invention. However, one skilled in the art will appreciate how the present invention can be used, both with and without these implementation details. In other cases, well-known methods, procedures, and components are not described in detail so as not to unduly obscure the features of the present invention.

[27] In addition, from the foregoing it is clear that the invention is not limited to the above implementation. Numerous possible modifications, alterations, variations, and substitutions that retain the spirit and form of the present invention will be apparent to those skilled in the art.

[28] FIG. 1 shows a longitudinal section of one of the options for assembling an air-fuel mixture combustion device. As an air-fuel fuel, for example, a pulverized coal mixture with a different ratio of constituent substances can act. The device contains an insulating housing 101, to which an air supply line is connected to the housing through a detachable element made in the form of a fitting 102, and in which the initiating part 105 of the electrode system, made adjustable, is placed with the help of fasteners 103. The initiating part 105 is connected to the removable part 104 extending outside the body 101, for example, by means of a sleeve or otherwise. In the preferred embodiment, the initiating part 105 is provided with a threaded connection, with which the removable part 104 of the electrode system is screwed into the initiating part, which provides ease of replacement of the removable part and improved maintainability. In this version, the initiating part 105 also has holes for installing the breakdown distance regulators, made in the form of screwed screws 106. The housing 101 also has slots for installing a viewing window 107. In this version, the insulating housing 101 is entirely made of fiberglass and is collapsible. This insulating material is characterized by good heat resistance, high resistivity and strength, which further ensures the stability of the device. Housing 101 is assembled using standard products, namely bolts, washers, screws and nuts. Such an implementation provides ease of assembly and disassembly of the body 101, as well as the strength of the connection of its structural elements, which together contributes to an increase in maintainability. The presence of a viewing window 107 in the housing provides easier control of the process of setting the breakdown distance on the screws 106, and also, as a consequence, the discharge ignition process itself. The viewing window 107 is made of a heat-resistant material that can withstand high ignition temperatures, such as pulverized coal. The air supply line with fitting 102 provides not only the movement of the discharge ignited in the electrode part, but also the cooling of the device due to heat transfer by the air flow. The removable part 104 of the electrode system is placed outside the housing and is located in such a way that the removable part 104 does not come into contact with the flow, while the discharge displaced by the air flow is within the reach of the mixture. This eliminates the abrasive wear of the working sections of the elements, thereby contributing to the stable ignition of the discharge. In addition, the detachable portion 104 can be easily replaced when heavy wear occurs during the operation of the device. In the general case, the setting of the breakdown distance can be carried out by, among other things, changing the length of the fastener or the depth of its fixation in the body elements due to screwing or otherwise, as well as tilting the breakdown sections of the electrode system to each other using, for example, their spherical connection with the body. In the preferred embodiment, the adjustment of the breakdown distance is carried out using regulators made in the form of movable screws 106, by screwing them into holes in the initiating part 105 of the electrode system. The implementation of the regulators in the form of movable screws 106 ensures their easy replacement, due to the fact that the discharge in this case is primarily initiated on the screws themselves due to the breakdown of the air space located between them and which is the part of the electrode system with the smallest breakdown distance, as well as the simplicity of the the process of setting the breakdown distance, which ensures the stability of the ignition of the electric discharge.

[29] FIG. 2 shows a cross section of one embodiment of the claimed device. In addition to the elements mentioned above, the section shows the connection with the body of the current supply lines to the electrode system, made in the form of high-voltage connectors 108, as well as wires 109 that maintain contact between the source and the system. The current supply lines can also be provided with busbars supporting the wires 109. The busbars prevent accidental contact of the wires with the case, which ensures stable operation of the device.

[30] FIG. 3 shows a general view of one of the embodiments of the air-fuel mixture combustion device.

[31] FIG. 4 is a block diagram illustrating one embodiment of the air-fuel mixture combustion method. It includes pre-setting the breakdown distance on the air-fuel mixture combustion device using an adjustable initiating part, then further connecting the device itself to the line in which the air-fuel mixture is transferred. The connection is carried out in such a way as to ensure that the removable part of the electrode system extending beyond the housing does not come into contact with the mixture flow, but the electric discharge displaced by the air flow is within the reach of the air-fuel mixture. The next step is to supply air through the supply lines, then create an electric discharge in the electrode system by applying voltage to it through the voltage supply lines, which leads to the movement of the ignited discharge by the air flow along the outgoing part of the system to the mixture and the interaction of the discharge with fuel particles with their ignition , which ultimately leads to the combustion of the air-fuel mixture. They can also carry out additional adjustment of the breakdown distance depending on various parameters of the system, for example, the temperature of the supplied air flow and its speed, which additionally contributes to the stability of the discharge ignition. The air-fuel fuel can be a dust-air mixture with a different content of components, used, for example, to ignite furnace spaces.

[32] The device operates as follows. Using screws 106, the required breakdown distance is set in the initiating part 105 of the electrode system. Then the combustion device is connected to a line carrying, for example, a dust-air mixture. The connection is carried out in such a way that the removable part 104 does not come into contact with the mixture flow, but the electric discharge displaced by the air flow is within the reach of the dust-air mixture. Further, to the housing 101, in which the wires 109 are located and the initiating part 105 of the electrode system is securely fixed with the help of fasteners 103, the air supply line is connected through the fitting 102 and the current supply lines are connected from the current source to the high-voltage connectors 108. Using the viewing window 107, check the set breakdown distance and supply air through the air supply line. Then voltage is applied to the system through the voltage supply lines, followed by ignition of a discharge between the screws 106, which is displaced by the air flow to the removable part 104 of the system. This leads to the interaction of the discharge with the particles of coal-dust-air fuel with their ignition, which ultimately leads to the combustion of the air-fuel mixture. If necessary, the breakdown distance can be additionally adjusted depending on various parameters of the system, for example, the temperature of the incoming air flow and its speed, which additionally contributes to the stability of the discharge ignition.

[33] Thus, the mentioned elements directly affect the technical result, which consists in ensuring the formation of a stable gaseous diffusion discharge and, as a result, the effective ignition of the air-fuel mixture due to the increased maintainability and wear resistance of the electrode system.

[34] The present application materials provide a preferred disclosure of the implementation of the claimed technical solution, which should not be used as limiting other, private embodiments of its implementation that do not go beyond the requested scope of legal protection and are obvious to specialists in the relevant field of technology.

Claims (17)

1. An air-fuel mixture combustion device, comprising an insulating housing with an air supply line, inside which an electrode system and voltage supply lines are installed, the electrode system having an initiating part connected to each other, made adjustable and attached to the housing from the inside, and a removable part extending beyond body limits. 2. The device according to claim 1, characterized in that the body is collapsible. 3. The device according to claim 1, characterized in that the body is made of fiberglass. 4. The device according to claim 1, characterized in that a viewing window is made in the housing. 5. The device according to claim 1, characterized in that the voltage supply line contains at least one bus connected to any of the electrodes. 6. The device according to claim 1, characterized in that the initiating part of the electrode system has breakdown voltage regulators. 7. The device according to claim 6, characterized in that the breakdown voltage regulators are made in the form of movable screws. 8. The device according to claim 1, characterized in that the connection of the initiating and removable parts of the electrode system is threaded. 9. The method of combustion of the air-fuel mixture, in which: - set the required breakdown distance on the air-fuel mixture combustion device using an adjustable initiating part, - connect the air-fuel mixture combustion device to the line carrying the air-fuel mixture in such a way as to ensure that there is no contact between the removable part of the electrode system and the mixture extending beyond the body, - supply air through the air supply line, - create a gas diffusion discharge in the electrode system by supplying a breakdown voltage through the voltage supply lines, - carry out the ignition of the line through the interaction of the gas diffusion discharge plasma displaced by the air flow and the air-fuel mixture, - combustion of the air-fuel mixture is carried out. 10. The method according to claim 9, characterized in that the breakdown distance is additionally adjusted. 11. The method according to claim 9, characterized in that a pulverized coal mixture is used as the air-fuel mixture.

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