Automatic modular burner

Abstract

FIELD: thermal power engineering.SUBSTANCE: invention relates to an automatic, modular, gas, modulating burner with forced air supply. A forced-air modular burner comprises a gas ramp, a housing and a flame head including a shell, a retaining washer, a first mixing unit designed to supply a gas-air mixture to the zone of the internal pilot flare, and a second mixing unit designed to supply a gas-air mixture to the zone of the external flare, which covers the internal flare. The shell has the form of a cylindrical tube with a confuser and an outlet edge, the surface of which is located perpendicular to the surface of the cylindrical tube. The thrust washer is made in the form of a ring, is located at the outlet of the combustion head, can move along the axis of the combustion head and is designed to change the size of the gap intended for the passage of air and formed between the shell and the thrust washer. The first mixing unit comprises a gas distribution pipe located along the axis of the combustion head, wherein the end of the gas distribution pipe located on the side of the combustion head outlet is equipped with a distributor, which is a support for several gas outlet nozzles and a swirler. One end of each gas outlet nozzle of the first mixing unit communicates with the cavity of the gas distribution pipe, and the other is built into the swirler. The second mixing unit comprises a gas-distributing manifold, several gas pipes with gas outlet nozzles, wherein the gas pipes are located near the shell and communicate with the internal cavity of the gas-distributing manifold. The gas outlet nozzles of the second mixing unit are positioned in such a way that the gas stream from them is directed into the converging part of the shell. The internal cavity of the gas distribution pipe of the first mixing unit is isolated from the internal cavity of the gas distribution manifold of the second mixing unit. Gas is supplied to the manifold of the second mixing unit through the boiler gas pipeline, on which a pressure regulator, the first automatic shut-off valve with a safety shut-off function (the first valve) and the second automatic shut-off valve with a safety shut-off function (the second valve) are installed in series along the gas flow. The pressure regulator can be used as a separate device or can be built into the first valve, and gas is supplied to the gas distribution pipe through the pilot flare gas pipeline, on which an automatic shut-off pilot valve with a safety shut-off function is located. The pilot flare gas pipeline communicates with the boiler gas pipeline at a place located between the first valve and the second valve.EFFECT: reducing the content of nitrogen oxides NOx and safe operation of the burner without extinguishing throughout the entire range of regulation of the burner thermal power.1 cl, 5 dwg

Description

[0001] Technical field

[0002] This invention relates to thermal power engineering, specifically to an automatic, modular, modulating burner with forced air supply (hereinafter referred to as the burner). The burner is designed for combustion of gaseous fuel. The burner is intended for use in stationary steam and hot water boilers and waste heat boilers.

[0003] Prior Art - Automatic Block Burners

[0004] The automatic block burner includes technical means for supplying gas and air to the combustion zone, mixture formation, ignition, flame stabilization, and automatic combustion process control. Automatic block burners are known from patents [1] - [6].

[0005] Automatic block burners consist of the following functional parts:

[0006] - body and flame head with unit(s) for mixing fuel with air;

[0007] - suction box with an air damper (hereinafter referred to as the damper) with a servo drive;

[0008] - fan wheel with motor and starter;

[0009] - gas control valve (hereinafter referred to as the valve) with servo drive;

[0010] - gas rail and / or liquid fuel rail;

[0011] - ignition transformer for ignition electrodes;

[0012] - devices for torch control and pressure measurement of media;

[0013] - microprocessor control device.

[0014] Prior art - methods for regulating the thermal power of a burner

[0015] The burner's thermal output is regulated by changing the air quantity (by changing the damper position in the suction box and / or by changing the fan speed) and the gas flow rate (by changing the valve position in the boiler's gas pipeline). The damper and valve positions are regulated by their servomotors, whose operation is coordinated. However, many burner manufacturers add an additional method to this power regulation method [7] - [9], which enables a high modulation ratio that can actually be achieved on a specific boiler. This type of burner is capable of guaranteeing a minimum to maximum output ratio of 1:10 due to its ability to ensure stable combustion without flame breakthrough, flame liftoff, or flame tearing off the burner throughout the entire burner control range.This is achieved by using an adjustment ring located at the burner's combustion head outlet and moving it along the combustion head axis to change the size of the annular gap designed to allow air to enter the flame zone. By changing the annular gap size, the air flow velocity through the gap changes while maintaining the same air flow. This method is important for high-power burners, where the air flow significantly increases during ignition and at full load. The presence of an adjustment ring allows for optimal air velocity at the combustion head outlet to ensure flame stability. A rod, driven by a servo drive, is used to move the adjustment ring.

[0016] Prior art - methods for ensuring the lowest value of nitrogen oxides NOx

[0017] It is well known that combustion product recirculation is used to reduce nitrogen oxide (NOx) emissions. In high-capacity boilers, combustion products are mixed with the air supplied by the fan, while in low-capacity boilers, combustion product recirculation can be easily implemented within the combustion chamber thanks to the special design of the combustion head. This requires creating conditions for the air or fuel-air mixture exiting the combustion head such that a low-pressure zone is created at its outlet, where the cool combustion products from the combustion chamber are directed. To achieve this, the cylindrical shell of the combustion head has a confuser and / or an exit edge at the outlet, the surface of which is perpendicular to the surface of the cylindrical shell. The confuser and / or exit edge form stagnation surfaces, which are designed to increase the velocity and swirl of the air or gas-air mixture.To direct the largest portion of the supplied air specifically to these braking surfaces, a gap is created at the combustion head outlet, through which the air is directed toward these braking surfaces. To create this gap, a retaining washer, shaped like a ring or disk, is placed at the combustion head outlet. An annular gap for the air passage is formed between the retaining washer and the inner surface of the shell. Furthermore, the gas outlet nozzles are positioned so that the gas stream is directed toward these braking surfaces. Such technical solutions are described by ELCO [DE] in burner patents

[10] -

[11] .

[0018] Description of the prototype for the invention

[0019] The closest analogue for the claimed block burner is the burner of the Weishaupt company [DE], which is described in most detail in the application

[12] for the invention "Mixing device and burner head for a burner with reduced NOx emissions". In the description of the application

[12] it is indicated that additional embodiments of the invention can be studied from the description of the WKGL70 dual fuel burner Version 3LN (LowNOx) multiflam® burner

[13] -

[15] . The known WKGL70 burner uses known technical solutions aimed at solving the corresponding problems, the description of which is given above in this description. Also, the known WKGL70 burner uses other technical solutions, which are described below.

[0020] The WKGL70 forced-air burner consists of a gas manifold, a housing, a gas manifold (hereinafter referred to as the manifold), and a combustion head. The combustion head includes a gas manifold, a first mixing unit, a second mixing unit, and a thrust washer.

[0021] The shell has the form of a cylindrical pipe with a confuser and an outlet edge, the surface of which is located perpendicular to the surface of the cylindrical pipe.

[0022] The thrust washer is made in the form of a ring, located at the outlet of the combustion head, has the ability to move along the axis of the combustion head and is designed to change the size of the gap intended for the passage of air and formed between the shell and the thrust washer.

[0023] The first mixing unit is designed to supply the gas-air mixture to the internal flare zone.

[0024] The second mixing unit is designed to supply the gas-air mixture to the external flare zone, which covers the internal flare.

[0025] The first mixing unit comprises a gas distribution pipe located along the combustion head axis. The gas distribution pipe is movable along the combustion head axis. This is accomplished by a support housing and a positioning unit with a rod connected to a servo drive. The first end of the gas distribution pipe (on the manifold side) is open, and the internal cavity of the gas distribution pipe on the first end communicates with the internal cavity of the manifold. A distributor is attached to the second end of the pipe (on the combustion head outlet side), which closes the internal cavity of the gas distribution pipe. The distributor supports several tubular gas outlet nozzles of the first mixing unit (hereinafter referred to as tubular nozzles), a truncated cone-shaped cup with a swirl element at the base, and a retaining washer. Accordingly, when the gas distribution pipe moves, all elements attached to it move along with it.

[0026] The first end of each tubular nozzle communicates with the cavity of the gas distribution pipe, from where gas enters the cavity of the tubular nozzle. The second end of the tubular nozzle is built into the swirler, from which gas enters the internal flame zone.

[0027] Air enters the internal flame zone from the annular gap between the glass and the retaining washer.

[0028] Additionally, the flame from the mixing chamber is directed through the swirler into the internal flame zone. The mixing chamber is formed by the walls of the distributor and the nozzle. Air enters the mixing chamber through openings in the distributor wall, and gas enters through round openings in the wall of each tubular nozzle. The mixing chamber contains dual ignition electrodes that ignite the gas-air mixture contained within the mixing chamber.

[0029] The second mixing unit contains several gas pipes with gas outlet nozzles located near the shell. The gas pipes communicate with the internal cavity of the manifold. The gas outlet nozzles are positioned so that the gas stream from them is directed toward the constriction (confuser) of the shell. To direct air into the confuser and the outlet edge of the shell, air passes through the gap between the shell and the retaining plate. This design of the second mixing unit is used to recirculate combustion products into the outer flame zone.

[0030] Air is forced into the combustion head by a fan.

[0031] The WKGL70 burner gas train is connected to the boiler gas pipeline. The gas train has a standard (known) set of fittings

[13] . Gas is supplied to the burner through the boiler gas pipeline. A pressure regulator, the first automatic electromagnetic or electrohydraulic shut-off normally-closed valve with a safety shut-off function (hereinafter referred to as the first valve), and a second automatic electromagnetic or electrohydraulic shut-off normally-closed valve with a safety shut-off function (hereinafter referred to as the second valve) are installed in series along the gas flow on the boiler gas pipeline.

[0032] The WKGL70 burner

[13] is ignited using an ignition burner. The ignition burner is used to ignite the burner at low gas flow rates. Gas is supplied to the ignition burner via the ignition gas line, which contains an automatic electromagnetic or electrohydraulic normally-closed ignition gas valve with a safety shutoff function (hereinafter referred to as the ignition gas valve). The ignition gas line communicates with the boiler gas line between the first and second valves.

[0033] To supply gas to the ignition burner, the first valve and the ignition gas valve open. The second valve is closed at this point. The ignition burner is a relatively long tube located inside the gas distribution pipe. Gas from the ignition burner travels through the gas distribution pipe and enters the mixing chamber, where it is ignited by a spark between electrodes. After the ignition burner ignites, the second valve opens, and gas from the boiler gas line begins to flow into the burner manifold. From the manifold, gas is fed into the gas distribution pipe of the first mixing unit and into the gas pipes of the second mixing unit. The ignition burner ignites the internal and external flames. The ignition gas valve then closes, and the ignition burner stops firing. The burner ignition mode is now complete.

[0034] In operating mode, gas enters the burner manifold via the boiler's gas pipeline, which contains the first and second valves and a damper that regulates the gas flow into the manifold. From the manifold, gas is distributed to the gas distribution devices of the first and second mixing units. Consequently, gas is supplied to the first and second mixing units via the same pipeline, and this gas flow is controlled by the same valves, namely the first and second valves, and regulated by the same damper. Consequently, the two flames (internal and external) are dependent on each other and on the changing gas flow rate within the manifold's interior, meaning that any problems with combustion stability or extinguishing will simultaneously affect both flames.

[0035] The application

[12] states that "the internal flame stabilizes combustion, while the exhaust gas recirculation inside the combustion chamber is carried out through the external flame." To stabilize the internal flame, the application

[12] proposes structurally and functionally complex devices, such as a highly complex-profile thrust washer and an additional third mixing unit, the operation of which uses movable devices in the burner body cavity. In the actually manufactured WKGL70 burner

[13] -

[14] , such complex devices are not used, and, therefore, the problem of ensuring a stable internal flame without extinguishing in the actual WKGL70 burner is not solved. Consequently, the issue of safe operation of the WKGL70 burner is not resolved.

[0036] Essence of the invention

[0037] The technical problem lies in expanding the range of automatic block burners with forced air supply (hereinafter referred to as burners).

[0038] The proposed burner uses technical solutions that are aimed at achieving:

[0039] - high modulation ratio applicable to boiler;

[0040] - reducing the value of nitrogen oxides NOx;

[0041] - safe operation of the burner without extinguishing throughout the entire range of regulation of the thermal power of the burner;

[0042] - preventing thermal overload of the parts of the first mixing unit.

[0043] The technical result in the invention is achieved by the fact that a burner with forced air supply is proposed, containing a first mixing unit intended for supplying a gas-air mixture to the zone of an internal (pilot) flare, and a second mixing unit intended for supplying a gas-air mixture to the zone of an external flare, which covers the internal flare.

[0044] The burner consists of a gas ramp, a body and a flame head.

[0045] The flame head includes a shell, a thrust washer, and the first and second mixing units.

[0046] The shell has the form of a cylindrical pipe with a confuser and an outlet edge, the surface of which is located perpendicular to the surface of the cylindrical pipe.

[0047] The thrust washer is made in the form of a ring, located at the outlet of the combustion head, has the ability to move along the axis of the combustion head and is designed to change the size of the gap intended for the passage of air and formed between the shell and the thrust washer.

[0048] The first mixing unit contains a gas distribution pipe located along the combustion head axis. The end of the gas distribution pipe, located at the combustion head outlet, is equipped with a distributor, which supports several gas outlet nozzles and a swirler. One end of each gas outlet nozzle communicates with the internal cavity of the gas distribution pipe, while the other is integrated into the swirler.

[0049] The second mixing unit contains a gas-distributing manifold and several gas pipes with gas outlet nozzles. The gas pipes are located near the shell and communicate with the cavity of the gas-distributing manifold. The gas outlet nozzles of the second mixing unit are positioned so that the gas stream from them is directed into the converging nozzle of the shell.

[0050] The internal cavity of the gas distribution pipe of the first mixing unit is isolated from the internal cavity of the gas distribution manifold of the second mixing unit. Gas is supplied to the manifold of the second mixing unit via the boiler's gas pipeline, which is connected in series along the gas flow: a pressure regulator, a first automatic shut-off valve with a safety shut-off function (the first valve), and a second automatic shut-off valve with a safety shut-off function (the second valve). The pressure regulator can be used as a separate device or can be integrated into the first valve.

[0051] Gas is supplied to the gas distribution pipe through the pilot flare gas pipeline, on which an automatic shut-off pilot valve with a safety shut-off function is located, while the pilot flare gas pipeline communicates with the boiler gas pipeline at a location located between the first valve and the second valve.

[0052] Separate gas pipelines are used to supply gas to the gas distribution devices (pipe and manifold), each with a shut-off valve with a safety shut-off function. This type of gas supply for the internal and external flares is called independent.

[0053] The presence of an internal (pilot) torch, operating continuously throughout the entire period of burner operation and with constant power, with an independent gas supply, ensures safe operation of the burner without burner extinguishing in the entire range of regulation of the burner's thermal power.

[0054] List of figures explaining the design of the burner

[0055] Fig. 1 - Schematic diagram of the burner.

[0056] Fig. 2 - General view of the burner with cutouts.

[0057] Fig. 3 - A flame head in which the thrust washer is extended from the flame head in a downstream direction.

[0058] Fig. 4 - A flame head in which the thrust washer is pushed into the flame head in an upstream direction.

[0059] Fig. 5 - Enlarged view of the mixing chamber.

[0060] Information confirming the possibility of carrying out the burner

[0061] Fig. 1-5 shows the burner, where: 1 - burner; 2 - body;

[0062] 3 - flame head; 4 - fan; 5 - gas ramp;

[0063] 6 - air fan electric motor;

[0064] 7 - air control damper (hereinafter referred to as damper);

[0065] 8 - damper servo;

[0066] 9 - gas distribution pipe; 10 - gas distribution manifold (hereinafter manifold);

[0067] 11 - thrust washer; 12 - thrust washer servo drive;

[0068] 13 - ignition transformer;

[0069] 14 - gas disc control valve (hereinafter referred to as the valve);

[0070] 15 - valve servo drive; 16 - boiler gas pipeline; 17 - pressure regulator;

[0071] 18 - first valve; 19 - second valve; 20 - pilot valve;

[0072] 21 - pilot flare gas pipeline;

[0073] 22 - cylindrical shell pipe; 23 - shell confuser;

[0074] 24 - output edge of the shell; 25 - support body; 26 - nozzle;

[0075] 27 - distributor;

[0076] 28 - gas outlet tubular nozzles of the first mixing unit;

[0077] 29 - glass; 30 - swirl;

[0078] 31- annular gap for internal torch air;

[0079] 32 - mixing chamber; 33 - air holes in the wall of the glass;

[0080] 34 - gas outlet slots; 35 - gas pipes;

[0081] 36 - gas outlet nozzles of the second mixing unit;

[0082] 37 - annular gap for air for external torch; 38, 39 - guide edges of the thrust washer.

[0083] Burner 1 (Fig. 1) has a housing 2, a combustion head 3, an air fan 4 located in the housing 2, and a gas ramp 5. Electric motor 6 rotates fan 4. Air enters through the suction box into the housing 2 and then into the combustion head 3. In the suction box, there is a damper 7, moved by a servo drive 8. Damper 7 regulates the amount of air for combustion. When the burner stops, the air damper completely closes the box.

[0084] Burner 1 comprises a first mixing unit designed to supply a gas-air mixture to the internal (pilot) flare zone, and a second mixing unit designed to supply a gas-air mixture to the external flare zone encompassing the internal flare. Gas distribution devices of the first and second mixing units are located in housing 2 and / or combustion head 3, namely, gas distribution pipe 9 designed to supply gas for the internal (pilot) flare, and manifold 10 (hereinafter referred to as manifold) designed to supply gas for the external flare. Gas distribution pipe 9 is located along the axis of combustion head 3.

[0085] At the outlet of the combustion head 3, there is a support washer 11. The support washer 11 can move along the axis of the combustion head 3. To move the support washer 11, a servo drive 12 is provided in the burner.

[0086] The ignition of the air-fuel mixture occurs using a double ignition electrode (not shown), for which an ignition transformer 13 is provided. The flame is controlled using a photoelectric sensor (not shown).

[0087] A valve 14 with a servo drive 15 is used as a gas flow regulator.

[0088] Burner gas train 5 is connected to boiler gas line 16. The gas train has a standard (known) set of fittings

[13] ,

[15] . According to Federal Norms and Rules for the Safety of Gas Distribution and Gas Consumption Systems, two shut-off valves with a safety shut-off function (in this case, a safety shut-off is a slow-opening and rapid-closing valve) must be installed on the gas pipeline before each boiler burner. The second valve is installed in case the first valve eventually becomes leaky or the actuator fails.

[0089] Gas is supplied to the manifold 10 of the second mixing unit through the gas pipeline of the boiler 16. A pressure regulator 17, a first automatic electromagnetic or electrohydraulic shut-off normally-closed valve 18 with a safety shut-off function (hereinafter referred to as the first valve 18), a second automatic electromagnetic or electrohydraulic shut-off normally-closed valve 19 with a safety shut-off function (hereinafter referred to as the second valve 19) and a shutter 14 are installed in series along the gas flow on the gas pipeline of the boiler 16. The requirement for safe gas supply is met, since two shut-off valves with a safety shut-off function are used to supply gas to the second gas-distributing unit, namely the first valve 18 and the second valve 19.

[0090] Gas is supplied to the gas distribution pipe 9 through the gas pipeline 21 of the pilot flare, on which an automatic electromagnetic or electro-hydraulic shut-off normally-closed pilot valve 20 with a safety shut-off function (hereinafter referred to as the pilot valve 20) is located.

[0091] The gas pipeline 21 of the pilot flare communicates with the gas pipeline 16 of the boiler at a location located between the first valve 18 and the second valve 19. Therefore, the gas pipeline 16 of the boiler with the first valve 18 and then the gas pipeline 21 of the pilot flare with the pilot valve 20 are used to supply gas to the gas distribution pipe 9 of the first mixing unit. The requirement for safe gas supply is met, since two shut-off valves with a safety shut-off function are used when supplying gas to the first mixing unit, namely the first valve 18 and the pilot valve 20.

[0092] Gas pressure regulator 17 can be used as a separate device (Fig. 1) or can be built into the first valve (Fig. 2). Gas pressure regulator 17 provides gas supply at a constant pressure (p=const) for both the internal (pilot) flare and the external flare.

[0093] The shell (Fig. 3) has the form of a cylindrical tube 22 with a confuser 23 and an outlet edge 24, the surface of which is located perpendicular to the surface of the cylindrical tube. The inner edge of the outlet edge 24 forms the outlet opening of the flame head 3. The confuser 23 in the area of ​​the air flow path is used to locally increase the air flow velocity.

[0094] The first mixing unit comprises a gas distribution pipe 9, which can be configured to move along the axis of the flame head 3. For this purpose, a support body 25 is provided, a positioning unit with a rod (not shown), which is connected to a servo drive 12. The first end of the gas distribution pipe 9 is connected to a nozzle 26, by means of which the gas distribution pipe 9 is connected to the gas pipeline 21 of the pilot torch. The second end of the pipe (on the side of the outlet from the flame head) is closed by a distributor 27. The distributor 27 is a support for several (for example, four) tubular gas outlet nozzles 28 (hereinafter tubular nozzles 28) and a cup 29 in the form of a truncated cone with a swirler 30 in the area of ​​​​the base of the cone. A support washer 11 may be secured to the distributor 27, which in this case will move together with the gas distribution pipe 9. The support washer 11 may not be secured to the gas distribution pipe 9.In this case, the gas distribution pipe 9 remains stationary, and the support washer 11 moves thanks to the servo drive 12.

[0095] One end of each tubular nozzle 28 (Fig. 5) is connected to the cavity of the gas distribution pipe 9, from where gas enters the cavity of the nozzle. The other end of the tubular nozzle is built into the swirler 30 and distributes gas into the flame of the inner (pilot) flare. Air from the flame tube enters the zone of the inner flare through the annular gap 31 between the cup 29 and the retaining washer 11. Additionally, the flame from the mixing chamber 32 enters the flame of the inner flare through the swirler 30. The mixing chamber 32 is formed by the walls of the distributor 27 and the cup 29. Air from the flame head enters the mixing chamber 32 through openings 33 in the wall of the cup 29 or in the wall of the distributor (not shown). Gas enters the mixing chamber 32 through longitudinal and / or transverse gas outlet slots 34 made in the wall of each tubular nozzle 28. The gas outlet from the slots, in contrast to the round holes made in the prototype nozzles [12, 13], makes it possible to prevent the mixing chamber parts from thermal overload.The ignition electrodes (not shown) are located in the mixing chamber 32.

[0096] The second mixing unit (Fig. 3) contains several (for example, eight) gas pipes 35 with gas outlet nozzles 36. The gas pipes 35 are located near the wall of the shell and are connected to the manifold 10.

[0097] The internal cavities of the gas distribution pipe 9 and the collector 10 are isolated from each other.

[0098] Gas outlet nozzles 36 are positioned in such a way that the gas stream from them is directed into the confuser 23 (narrowing zone) of the shell for good mixing of gas with air.

[0099] Backup washer 11 is designed to form annular gap 37, which allows air to pass into the outer flame zone. This annular gap 37 is formed between the shell and backup washer 11. Backup washer 11 is a ring-shaped device whose surface is perpendicular to the axis of the inner bore of the ring. Air guide edges 38 and 39 are located on the outer and inner edges of the ring.

[0100] When the thrust washer 11 moves, the size of the annular gap 37 changes.

[0101] Figure 3 shows the combustion head in ignition mode, when the gas and air supply to the outer flame zone is minimal (minimum burner power). This requires increased gas-air mixture velocity. To achieve this, the thrust washer is extended downstream from the combustion head 3, and the annular gap 37 is at its minimum size.

[0102] Figure 4 shows the combustion head in the burner's medium or maximum power mode, when the gas and air supply to the outer flame zone is at maximum levels. The thrust washer 11 is pushed into the combustion head 3 in an upstream direction, and the annular gap 37 is at its maximum size. It should be noted that this position of the thrust washer 11 is approximate, as it does not take into account the backpressure in the combustion chamber. Therefore, the actual position of the thrust washer 11 is determined during the performance adjustment phase, and the position at maximum loads may be intermediate.

[0103] The ability to vary the annular gap, and therefore the air velocity, ensures stable combustion without flame breakthrough, flame liftoff, or burner blowoff across the entire control range. This ensures a high modulation ratio that can be achieved on a specific boiler.

[0104] The burner has a control device (controller), the functions of which include: controlling the ignition electrodes, collecting information from flame and pressure control devices, controlling the gas ramp fittings, and controlling the servo drives.

[0105] The burner works as follows.

[0106] Before burner ignition (Fig. 1), first valve 18, second valve 19, and pilot valve 20 are closed. Shutter 14, which determines the gas flow to the external flame, is set to the ignition position at reduced power. Damper 7, which regulates the amount of air to the internal and external flames, and retaining washer 11, which regulates the air velocity at the outlet of combustion head 3, are set to the position determined during the operational adjustment stage in the minimum burner power mode.

[0107] First, the internal (pilot) flame is ignited. In this description, the pilot flame is defined as a flame that operates continuously throughout the entire burner flame operation period

[16] . To do this, the first valve 18 is opened (while the second valve 19 remains closed). Then the pilot valve 20 is opened. The starting gas enters the first mixing unit, namely the gas distribution pipe 9, through the first valve 18 of the boiler gas pipeline 16 and the pilot valve 20 of the gas pipeline 21 of the pilot flame. From the gas distribution pipe 9, the gas enters the tubular nozzles 28. Through the gas outlet slots 34 of the tubular nozzles 28, the gas enters the mixing chamber 32. Air pumped by the fan from the combustion head 3 enters the mixing chamber 32 through the openings 33 in the cup 29.

[0108] Also, gas from tubular nozzles 28 enters the combustion chamber of the boiler, where air from the combustion head 3 enters through the annular gap 37.

[0109] The electric ignition devices located in mixing chamber 32 ignite the gas-air mixture with a spark, and the flame formed in mixing chamber 32 ignites the gas-air mixture in the boiler combustion chamber. At this point, the ignition stage of the internal (pilot) flame is complete.

[0110] The internal (pilot) flame always operates at constant power and constant pressure (p=const). The internal flame must be stable. If the external flame goes out, the internal flame ignites it.

[0111] The thermal power of the internal (pilot) flare must not exceed 0.12 MW, in accordance with the requirements for not exceeding the starting power of the ignition burner. Meeting this requirement allows for burner ignition at low gas flow rates. In this regard, the internal (pilot) flare is similar to the ignition burner in the prototype.

[0112] The internal (pilot) flame presence monitoring must be established within 3 seconds. If a stable internal (pilot) flame is established, the electric igniter is turned off.

[0113] Then the external flame is ignited. To do this, the second valve 19 is opened, and gas flows through the boiler's gas line 16 at a constant pressure (p=const) into the second mixing unit, namely, the manifold 10. From the manifold 10, gas enters the combustion chamber through gas distribution pipes 35 with gas outlet nozzles 36. Air from the combustion head 3 enters the combustion chamber through annular gap 37. The internal (pilot) flame ignites the external flame. This completes the burner ignition process.

[0114] Confuser 23 and edge 24 of the shell serve as stagnation surfaces for the gas-air mixture of the second mixing unit. If the gas-air mixture flows against these stagnation surfaces, turbulent regions are formed that extend into the downstream flame front. The outer flame front is formed not at the flame head, but at a distance from it. Furthermore, a zone of overpressure forms upstream of the stagnation surfaces, while a zone of low pressure forms downstream. These low-pressure zones and turbulent regions cause increased recirculation of combustion products from the combustion chamber into the flame, which lowers the flame temperature and, as a result, reduces the nitrogen oxides formed during combustion of the gas-air mixture.

[0115] Furthermore, when the block burner is operating over a wide power range, the gas flow rate to the internal flame is not adjusted. Burner power is adjusted by varying the gas flow rate and the amount of air supplied to the external flame. The external flame receives the majority of the total gas supplied. The position of the retaining washer 11 is adjusted to ensure stable combustion without flame breakthrough, flame liftoff, or flame tearoff across the entire burner control range.

[0116] Bibliography:

[0117] 1. RU 229727 U1 "Automated burner device".

[0118] 2. RU 227070 U1 "Block burner".

[0119] 3. RU 260870 C1 "Block burner device".

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[0121] 5. EP 0751350 B1 "Incineration plant and method for controlling and / or monitoring an incineration plant".

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[0123] 7. DE 7640744 U1 "Large burner, especially for liquid fuels."

[0124] 8. Manual for adjustment and maintenance of gas burners GP-250 T, GP-280 T, OILON, 40250119RU, p. 18. Found on the Internet at: https: / / www.cok.ru / library / instructions / oilon / gorelki-gazovye / 11454 / 30785.pdf

[0125] 9. RU 2660592 C1 "Burner head of the burner device".

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[0127] 11. US 7891971 B2 "Combustion head and method for burning fuel".

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[0129] 13. Installation and operating instructions for industrial burners WKGL70 / …, 3LN (LowNOx) design multiflam® from Weishaupt with electronic linked regulation W-FM100, 83057546 - 1 / 2003, pp. 8, 12, 20-21, 42-43, 45, 52. Found on the Internet at: https: / / www.teplogamma.ru / downloaa7files / 575rus_03.pdf

[0130] 14. Weishaupt WKGL70 dual fuel burner version 3LN (Low NOx) multiflam®, 1 / 2003 GB. Found online at: https: / / cms.esi.info / Media / documents / Weish_WKGL70_ML.pdf

[0131] 15. Weishaupt. Installation and operating instructions. Gas burners WKmono-G80 / 2-A / ZM-3LN (W-FM 100 / 200), 83300146 1 / 2016-04, pp. 13-14. Found on the Internet at: https: / / www.cok.ru / library / instructions / weishaupt / gorelki-gazovye / 29085 / 107555.pdf?ysclid=ml9fc985uo923134498

[0132] 16. Flare System Safety Guide. Approved by Order of the Federal Service for Environmental, Technological and Nuclear Supervision of December 22, 2021, No. 450, p. 21.

Claims

A forced-air block burner comprising a gas ramp, a housing and a combustion head including a shell, a retaining washer, a first mixing unit designed to supply a gas-air mixture to the zone of the internal - pilot flame, and a second mixing unit designed to supply a gas-air mixture to the zone of the external flame, which covers the internal flame, wherein the shell has the form of a cylindrical pipe with a confuser and an outlet edge, the surface of which is located perpendicular to the surface of the cylindrical pipe; the retaining washer is made in the form of a ring, is located at the outlet of the combustion head, has the ability to move along the axis of the combustion head and is designed to change the size of the gap intended for the passage of air and formed between the shell and the retaining washer; the first mixing unit contains a gas distribution pipe located along the axis of the combustion head, wherein the end of the gas distribution pipe,located on the side of the outlet from the combustion head, is provided with a distributor, which is a support for several gas outlet nozzles and a swirler, wherein one end of each gas outlet nozzle of the first mixing unit communicates with the cavity of the gas distributing pipe, and the other is built into the swirler; the second mixing unit contains a gas distributing manifold, several gas pipes with gas outlet nozzles, wherein the gas pipes are located near the shell and communicate with the internal cavity of the gas distributing manifold, and the gas outlet nozzles of the second mixing unit are arranged in such a way that the gas stream from them is directed into the confuser of the shell, characterized in that the internal cavity of the gas distributing pipe of the first mixing unit is isolated from the internal cavity of the gas distributing manifold of the second mixing unit, wherein gas is supplied to the manifold of the second mixing unit through the gas pipeline of the boiler, on which a pressure regulator is installed sequentially along the flow of gas,a first automatic shut-off valve with a safety shut-off function - the first valve and a second automatic shut-off valve with a safety shut-off function - the second valve, wherein the pressure regulator can be used as a separate device or can be built into the first valve, and gas is supplied to the gas distribution pipe through the pilot flare gas pipeline, on which the automatic shut-off pilot valve with a safety shut-off function is located, wherein the pilot flare gas pipeline communicates with the boiler gas pipeline at a location located between the first valve and the second valve.

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