EP3058279A1

EP3058279A1 - Method for the ignition of a power plant burner, and coal dust burner suitable for the method

Info

Publication number: EP3058279A1
Application number: EP14777675.1A
Authority: EP
Inventors: Alfons Leisse; Sebastian Rehfeldt
Original assignee: Mitsubishi Hitachi Power Systems Europe GmbH
Current assignee: Mitsubishi Power Europe GmbH
Priority date: 2013-10-18
Filing date: 2014-10-02
Publication date: 2016-08-24
Anticipated expiration: 2034-10-02
Also published as: EP3058279B1; CA2927707A1; US10309644B2; CN105637296B; CN105637296A; WO2015055443A1; DE102013111504A1; DE102013111504B4; KR20160071378A; US20160238239A1; JP2016533467A

Abstract

In the case of a burner, in particular coal dust burner (12), comprising a fuel pipe (1), a fuel nozzle (2), at least one ignition and/or heat source (3') and a pipe (7, 10) which conducts an oxygen-containing gas and/or recirculated flue gas, wherein the at least one ignition and/or heat source (3') is arranged in the burner interior and is in the form of or comprises an electric heating and/or ignition device (14') by means of which, exclusively by conversion of electrical current into heat energy, the amount of heat energy required within the burner for the initiation and continuation of the initial pyrolysis and ignition is generated and/or provided in the burner interior, in particular in the region of the fuel ignition site that forms, it is the intention to provide a solution which, dispensing with the use of gaseous, liquid or solid additional fuel, permits frequent start-up and shut-down of the burners of a steam generator of a large-scale thermal power plant in an inexpensive manner with regard to fuel consumption, and provides a burner suitable for this purpose. This is achieved in that a stabilizing ring (9) with toothed ring (15) is a constituent part of the electric heating and/or ignition device (14') arranged in the mouth region (13) of the fuel nozzle (2).

Description

Method for igniting a power plant burner and suitable for it

Pulverized coal burner

The invention is directed to a burner, in particular pulverized coal burner, comprising a fuel tube, a fuel nozzle, at least one ignition and / or heat source and a tube containing oxygen containing gas and / or recirculated flue gas, wherein the at least one ignition and / or heat source burner inside arranged and designed as an electrical heating and / or ignition device or includes such, which required inside the burner for the formation and the course of the initial pyrolysis and ignition amount of heat energy burner inside, especially in the area of forming fuel ignition location, exclusively by Conversion of electrical power into heat energy generated and / or provides.

Furthermore, the invention is directed to a method for igniting a particulate, in particular dusty, fuel by means of a burner, in particular pulverized coal burner, wherein the fuel in the burner promoted to within the burner in the region of the fuel nozzle forming ignition and the start of the burner for the formation and the course of an initial pyrolysis and ignition of the fuel delivered to the burner mouth is entered into the burner and / or the fuel conveyed therein exclusively by means of at least one ignition and / or heat source arranged in the burner, which heat source is in the form of a heating - And / or ignition device is formed in the burner or is arranged with such arranged in the burner heating and / or ignition device in heat-conducting and / or heat-transmitting active compound, the required amount of heat energy exclusively by Wandlerl ung electrical power generated in heat energy burner inside and / or provided

In connection with the feed-in of electrical energy from discontinuous, regenerative energy sources (eg photovoltaic or wind power plants) into the general power grid, pulverized coal-fired power plants must more frequently start at arbitrarily low partial loads or shut down be taken, which usually leads to the shutdown of individual or all burner levels of the combustion chamber of the steam generator of the power plant. The ignition of coal dust when starting the burner is usually carried out with the aid of gaseous or liquid additional fuels, such as natural gas or light fuel oil, which are ignited in a arranged on or in the respective pulverized coal burner ignition lance. Only after the formation of a continuously burning flame produced by the combustion of such a gaseous or liquid additional fuel can the pulverized coal usually be conveyed to the burners where they are ignited in the mouth region. By more frequent startup and shutdown in connection with the grid feed of electrical energy from renewable energy sources, the consumption of these auxiliary fuels increases sharply, resulting in a significant increase in the operating costs so equipped thermal pulverized coal power plants. When starting and stopping as well as in operation at very low partial loads therefore burners for gaseous or liquid fuels often have to be used for auxiliary firing. It is advisable to carry out such a support firing also with a solid, dusty fuel that can be burned by means of indirect firing systems, which include a previous intermediate storage of the processed coal dust, and suitable burners in the combustion chamber or the firing chamber of a steam generator.

In thermal power plants burners are used, by means of which solid, often dust-like, fuels such as lignite, hard coal, biomass are burned. For this purpose, it is necessary that in the respective burner or the respective burner device, the ignition of the respective particular dust-like fuel takes place. The ignition of fuels is basically determined by the processes of pyrolysis of the particulate, dusty fuel and the oxidation of the combustion of the resulting pyrolysis products. To initiate the required processes, the necessary, known boundary conditions must be met. For the

Firing of pulverized coal, for example, is a suitable fuel concentration, a sufficiently high heat transfer, a sufficient residence time of the dust particles in the region of the pyrolysis and ignition zone and the presence of primary oxygen or a Oxidizing agent indispensable prerequisites. Taking these conditions into account, the pyrolysis and oxidation of the pyrolysis products required for the ignition can generally be ensured. In practice, it is common for an ignition lance, which is operated within the burner, to be operated with gaseous fuel and forms a pilot flame, at which fuel conveyed in the burner is ignited.

From DE 33 27 983 A1 discloses a purely electrically operated ignition device is known, which has an ignition device which ignites from a primary air tube of the burner emerging fuel.

DD 240 245 A1 discloses a generic burner having an electric ignition device in the mouth region, by means of which a coal dust-air mixture is ignited. At the glowing electric ignition ignited coal dust passes and forms a Zündwirbel, which ensures that a arranged in this area the rear wall is also made to glow. A burner in which pulverized coal is ignited by means of an immersion in the fuel tube cross-section heating rod is also disclosed in DD 270 576 A1.

The invention has for its object to provide a solution that allows waiving the use of gaseous, liquid or solid additional fuel in terms of fuel consumption cost, frequent startup and shutdown of the burner of a steam generator of a large thermal power plant and a suitable burner This object is achieved by a burner with the features of claim 1 and a method having the features of claim 18. Inventive developments and expedient embodiments of the invention are the subject of the respective subclaims.

The solution is therefore first of all a burner, in particular a pulverized coal burner, which comprises a fuel tube, a fuel nozzle, at least one ignition and / or heat source and a tube carrying an oxygen-containing gas and / or recirculated flue gas, wherein the at least one ignition and / or or heat source arranged inside the burner and is designed as an electric heating and / or ignition, or such includes the heat energy required inside the burner for the emergence and the course of the initial pyrolysis and ignition burner inside, especially in the area of forming fuel Zündortes , Generated and / or provides exclusively by converting electrical power into heat energy, wherein a stabilizing ring with ring gear is part of the arranged in the mouth region of the fuel nozzle electric heating and / or ignition device.

Likewise, a method for igniting a particulate, in particular dust-like, fuel by means of such a burner, in particular pulverized coal burner is provided, wherein the fuel in the burner promoted to within the burner in the region of the fuel nozzle forming ignition and the start of the burner for the formation and the course of an initial pyrolysis and ignition of the fuel delivered to the burner mouth is entered into the burner and / or the fuel conveyed therein exclusively by means of at least one ignition and / or heat source arranged in the burner, which heat source is in the form of a heating - And / or ignition device is formed in the burner or is arranged with such arranged in the burner heating and / or ignition device in heat-conducting and / or heat-transmitting active compound, the required amount of heat energy exclusively by converting electric current in

Heat energy is generated inside the burner and / or provided, wherein the required amount of heat energy by means of a arranged in the mouth region of the fuel nozzle heating and / or ignition device in the burner and / or is introduced into the subsidized fuel, the component of which is a stabilizing ring with sprocket.

The invention is thus based in its first aspect on the fact that in a power plant burners, especially pulverized coal burners, which are subjected to a frequent startup process, can be operated more cost-effectively, that at the respective start for performing the pyrolysis and ignition of the particulate, in particular dusty , Total fuel required thermal energy and exclusively by means of an electric, ie by conversion of electric current, which generates for the initial pyrolysis and ignition of the particular dust-like fuel necessary amount of heat energy generating heating and / or ignition and is registered within the burner in the fuel delivered in the burner. By eliminating the need for an ignition lance operated with gaseous or liquid (supplemental) fuel, there is no need for constructive and costly measures for arranging such a burner lance in a respective burner and the utilities and shut-off devices necessary to provide the (supplemental) fuel. and control valves. In addition, eliminates the need for the operation of each ignition lance consumption of additional liquid, gaseous or solid fuel. The amount of energy necessary to start up such a burner, especially a pulverized coal burner, to carry out and ensure the necessary initial pyrolysis and ignition of the fuel, becomes solely electrical, i. By converting electrical current into heat energy, generated. Electric power is regularly available in large power plants at different voltage levels

Available. The respective initial initial ignition of the in the burner, especially pulverized coal burner, promoted particular dusty carbon and the necessary initiation and maintenance of an initial pyrolysis of the promoted in the burner fuel is thus exclusively by means of one or more electrically powered

Heating and / or ignition devices reached and is also registered only within the burner in the burner and / or the fuel. According to a further aspect of the invention, it is thus provided that a purely electrically operated ignition and / or heat source or heating and / or ignition device is arranged and formed inside the burner inside the burner. An additional aspect is that this purely electrically operated ignition and / or heat source or heating and / or ignition device required for the initial pyrolysis and the ignition of the fuel heat energy (quantity) in components or construction elements of the burner and thus in the Burner initiates and enters. From these components or construction elements, the registered heat energy (amount) can then be delivered to the fuel flowing past it and entered into this, so that this is about the required for the initial pyrolysis and ignition heat energy (quantity) is supplied. According to a further aspect, however, it is also possible for the purely electrically operated ignition and / or heat source or heating and / or ignition device to emit the heat energy (quantity) generated directly to the fuel flowing past it and to enter it. Finally, according to a further aspect of the invention, it is also possible for a plurality of electrically operated ignition and / or heat sources or heating and / or igniting devices to be arranged and configured inside the burner, in which case in particular at least one of the ignition and / or heat sources or heating and / or ignition means electrically generated heat energy into the burner, ie components or design elements of the burner, initiates or enters and another of the ignition and / or heat sources or the heating and / or ignition devices within the burner heat energy in the flowing therein Fuel initiates and enters. But it can also all

Heat sources or ignition devices heat energy exclusively in components and design elements of the burner initiate.

With regard to the method, another aspect is that, especially during start-up of the burner, within the burner for the

Emergence and the expiration of the initial pyrolysis and ignition required amount of heat energy without the use of another additional liquid, gaseous or solid fuel, except the initially pyrolyzed and ignited fuel generated. In the initial to be pyrolyzed Fuel is the dust-like or particulate fuel, in particular pulverized coal, which is also provided in the further operation of the burner as a feedstock fuel for combustion to produce the burner flame.

The amount of heat energy required in the burner for the formation and the course of the initial pyrolysis and ignition is generated by means of the heating and / or ignition exclusively by converting electrical current into heat energy and / or an arc and / or plasma and introduced into the fuel. By ensuring the necessary for the emergence and the course of the initial pyrolysis or the initiation and implementation of the initial pyrolysis residence time of fuel in the burner in the range of the necessary for the implementation of the pyrolysis temperature and standing with the fuel in heat-transmitting operative connection burner inside ( Wirk-) surface and / or contact surface and / or inner surface of the fuel pipe and or the heating and / or ignition device is achieved that the necessary heat input can be made in the fuel and the flow of pyrolysis and the ignition of the particular dusty fuel by means of the electric operated heating and / or ignition can be performed and guaranteed. A further aspect of the invention therefore also consists in the fact that the amount of heat energy required within the burner for the formation and the course of the initial pyrolysis and ignition is in contact or in contact with the flowing fuel at a residence time sufficient for the course of the initial pyrolysis and ignition Actively connected burner inside

Surface, in particular of the burner is registered in the fuel.

In this case, it is a further aspect of the invention expedient that the heat energy required within the burner for the formation and the course of the initial pyrolysis and ignition at a contact surface of the heating and / or ignition device burner inside is entered into the fuel with a for the Entry of the required amount of heat energy into the fuel to produce the initial pyrolysis and ignition sufficient residence time inside the burner with the fuel in contact or in Active compound is. This ensures that a sufficiently large contact surface, which takes place a heat input into the fuel conveyed past, is ensured. According to the invention, it is thus provided that the thermal energy is generated by means of an electric heating and / or ignition device, which is designed as part of the fuel nozzle and at least partially as a stabilizing ring with toothed ring and arranged in the opening region of the fuel nozzle. In this case, therefore, the burner or fuel nozzle which is usually present in burners and, in particular, the stabilizing ring with toothed ring optionally provided and arranged there, is designed as a heating and / or ignition device which generates electrical heat energy and delivers it to or into the burner and / or to the fuel. The burner according to the invention is therefore characterized in that a stabilizing ring with ring gear is part of the arranged in the mouth region of the fuel nozzle electric heating and / or ignition device. The inventive method provides that the required amount of thermal energy is entered by means of a arranged in the mouth region of the fuel nozzle heating and / or ignition in the burner and / or in the subsidized fuel, the component is a stabilizing ring with sprocket.

In this case, it is advantageous according to the invention that the toothed stabilizing ring is arranged at a distance in front of the mouth opening of the tube arranged concentrically within the fuel tube and in the center of the burner.

It is to ensure the sequence of the necessary pyrolysis further advantageous that the fuel nozzle is formed such that the zahnformige stabilizing ring is designed to be directed radially inward and funded in a fuel delivery cross section fuel flow or

Detects fuel dust flow, decelerates and deflects what the invention provides in development. Here, it is particularly useful if the fuel nozzle and / or the stabilizing ring with ring gear at least one of electric current flowable heating wire and / or at least one inductively heated area / have, which (r) respectively within the burner for the emergence and the Run the initial pyrolysis and ignition generated / generate and provide / provide heat energy required. This also provides the invention in an embodiment.

The burner, in particular pulverized coal burner, is characterized in that the electrical heating and / or ignition device, especially when starting the burner, in particular pulverized coal burner, within the burner for the formation and the course of the initial pyrolysis and ignition required amount of heat energy in the Forming fuel-ignition location without the use of another additional liquid, gaseous or solid fuel, except the initially pyrolyzed and ignited fuel produced and / or provides.

In this case, it is therefore further expedient for the burner to have / have a contact surface on the burner interior side and / or the electrical heating and / or ignition device or to be in heat-conducting and / or heat-transmitting active connection with the starting operation of the burner a sufficient for the expiration of the initial pyrolysis and ignition residence time with the fuel in the fuel pipe funded in contact or in operative connection is / are, what the invention also provides.

In an embodiment of the invention according to the invention, it is furthermore advantageous that a fuel nozzle having the stabilizing ring with toothed ring in the heat-conducting and / or heat-transmitting operative connection forms the burner inner surface area of the fuel tube and / or the contact surface. It is expedient here, moreover, for the surface on the burning surface to be wholly or partially part of the contact surface of the heating and / or ignition device, which the invention also provides. A particularly advantageous embodiment of the heating and / or ignition device is also that the fuel nozzle in the mouth region comprises a plurality of windings formed from a heating wire or resistance wire, which form the heating and / or ignition, which the invention also provides. Here, the windings of the heating wire can extend through the stabilizing ring and the ring gear, which the invention also provides in an embodiment.

In order to be able to heat adjacent combustion-surface-side surface areas and to be able to form a heat source, the invention is further characterized in that the windings of the heating wire extend through combustion chamber-side stabilizing ring-side surface areas of the fuel nozzle and the fuel tube. But it is not only possible that the electric heating and / or ignition

Part of a stabilizing ring with sprocket having fuel nozzle, it is also possible that the fuel nozzle and / or the stabilizing ring with sprocket form the electrical heating and / or ignition device, which the invention also provides.

In order to ensure the ignition of the pyrolysis products formed during the pyrolysis, the invention is characterized in that the fuel nozzle and / or the stabilizing ring with ring gear and / or the burner interior surface areas to a temperature of at least 200 ° C, in particular of> 450 ° C, is preferably formed of between 600 ° C - 700 ° C, heatable / are.

However, in addition to the heating ring formed in the stabilizing ring with toothed ring or designed as a stabilizing ring with toothed ring, and / or ignition device further electrical ignition and / or heat sources may be provided in the burner. The invention is therefore also characterized in development by ignition and / or heat sources, which form a combination of the electric current into heat energy converting heating and / or ignition device with an arc generating or a hot air generating, further heating and / or ignition device.

In particular, it is provided in a further development of the invention that the further electrical heating and / or ignition device comprises or forms a plasma torch which is directed in particular to the burner inner side surface and / or the contact surface and / or the stabilizing ring with ring gear and / or or the subsidized fuel transfers heat energy.

However, it may also be possible to use a hot-air delivery pipe as an electrical heating and / or ignition device, so that the invention also provides that the further electrical heating and / or ignition device comprises or form a equipped with an electric heater hot air conveyor pipe, with its burner inside mouth region is directed to the burner inner side surface and / or the contact surface and / or the stabilizing ring with ring gear and transfers heat energy to these and / or the subsidized fuel.

Thus, a plurality of heating and / or ignition devices, in particular of different types, can be realized and arranged on a burner. It is a combination of two heating and / or ignition devices, in particular the

Combination of an electric current in heat energy converting and an arc generating or a hot air generating heating and / or ignition, possible. The combination can thus consist in the burner inside a burner several ignition and / or heat sources or heating and / or ignition devices are formed and arranged, each enter or initiate either thermal energy in components or structural elements or burner devices or transferred to this or the Apply heat energy directly to the extracted fuel. Besides, it is possible for either one of these two Types of ignition and / or heat source or heating and / or ignition device burner inside the burner is arranged and designed.

Finally, the burner is also characterized in another embodiment of the invention by the fact that the electrical heating and / or ignition and / or the further electrical heating and / or ignition device, especially when starting the burner, within the burner for the emergence and the amount of heat energy required in the initial pyrolysis and ignition process in the region of the fuel-ignition location that is being formed without the use of another additional liquid, gaseous or solid fuel, except for the fuel which is initially to be pyrolyzed and ignited, producing / producing and / or providing / providing.

It is furthermore advantageous if the stabilizing ring with ring gear is at least part of an ignition and / or heat source, which the invention finally also envisages in the design of the burner.

In an advantageous embodiment of the method according to the invention, it is provided that the amount of heat energy required during startup of the burner within the burner for the formation and the course of the initial pyrolysis and ignition without the use of another additional liquid, gaseous or solid fuel, except for the initial to pyrolyzing and igniting fuel is generated. It is advantageous in a further embodiment of the invention that the heat energy required within the burner for the formation and the course of the initial pyrolysis and ignition at one with a sufficient for the expiration of the initial pyrolysis and ignition residence time with the flowing fuel in contact or in Actively connected burner inside surface of the burner is registered in the fuel and / or at a

Contact surface of the heating and / or ignition inside the burner is registered in the fuel, with sufficient for the entry of the required amount of heat energy into the fuel to produce the initial pyrolysis and ignition residence time inside the burner with the fuel Contact or is in operative connection, wherein the surface and / or the contact surface is / are formed by the fuel nozzle and / or the ring gear stabilizer ring. The fuel nozzle and / or the stabilizing ring can be formed in particular advantageously as an electrically operated heating and / or ignition device, that the fuel nozzle and / or the stabilizing ring has / has a heated by heating electric wire or an inductively heated area, by means of which in each case the amount of heat energy required within the burner for the formation and the course of the initial pyrolysis and ignition is generated and provided, which the invention also provides.

As an electrically operated heating and / or ignition but can also be a plasma torch or an arc-generating device use, so that it is also possible that the heat energy required within the burner for the formation and the course of the initial pyrolysis and ignition by means of a electric arc, in particular by means of a plasma torch, is generated and provided, which is directed in particular to the burner inner side surface and / or the contact surface and transmits the required amount of thermal energy to these and / or the subsidized fuel.

Another possibility of generating the heat energy necessary to trigger the initial pyrolysis or the initial pyrolysis process is to bring hot air into the region of the ignition or the location of the pyrolysis process, in which case within the burner for the formation and the course of the initial pyrolysis and ignition required amount of heat energy is generated and provided by means of a equipped with an electric heater hot air conveying pipe, which with its burner inside

Mouth area is directed in particular to the burner inner side surface and / or the contact surface and transmits the required amount of heat energy to these and / or the subsidized fuel. In particular, in this case, but also in all other cases, is suitable for the necessary for the expiration of the pyrolysis process and the ignition of the energy input, in particular the burner mouth with her / it provided therein burner-internals so that the for the emergence and the course of the Initial heat pyrolysis and ignition required amount of heat energy is entered via a burner inner surface and / or contact surface in the fuel, which is formed by the fuel nozzle and / or the stabilizing ring with ring gear or includes. However, it is also possible that the surface to be provided for the heat input into the fuel is not an immediate component of the heating and / or ignition device, but is provided by a burner device which is thus in heat-conducting or heat-transmitting operative connection, so that the surface inside the burner inner surface and / or or contact surface of a standing with the heating and / or ignition, in particular the fuel nozzle and / or the stabilizing ring with sprocket, in heat-conducting and / or heat-transmitting operative connection burner mouth side inner surface area of the fuel tube is formed. In order to ensure the ignition of the fuel and to carry out the necessary initial pyrolysis, it has proved to be particularly useful if the heat energy required for these processes generated in the region of the ignition of the fuel and then entered on the one hand via an active surface or contact surface in this area in the fuel but on the other hand via heat conduction and / or thermal radiation in others

Areas and other active surfaces and contact surfaces of the burner, in particular burner inner side surface areas of the fuel pipe, is passed. It is therefore also advantageous if, especially when starting the burner, within the burner needed for the formation and the course of the initial pyrolysis and ignition

Thermal energy is generated and / or provided by means of the heating and / or ignition device in the region of the forming Zündortes. For carrying out the pyrolysis process and the ignition of the fuel sufficiently high temperatures are fuel-dependent in the range of> 200 ° C, in particular> 450 ° C and preferably in the range between 600 ° C and 700 ° C. The invention therefore provides, in a further embodiment of the method, that the surface on the burner surface and / or the contact surface and / or the stabilizing ring with ring gear and / or a burner mouth side inner surface area of the fuel tube by means of the heating and / or ignition device to a temperature of> 200 ° C, in particular of> 450 ° C, preferably of between 600 ° C - 700 ° C, is heated. Thus, in sufficient to carry out the pyrolysis and the ignition of the fuel heat energy can be transferred to the fuel. The ignition temperature of solid fuels increases with increasing degree of coalification, ie with a lower percentage of volatile constituents. The particulate, in particular pulverulent, fuel can be conveyed in the burner, in particular in the fuel pipe or fuel delivery pipe, with a concentration between 0.1 and 10 kg (fuel) / (carrier gas) and / or a conveying speed between 5 and 30 m / s in the burner , Finally, in an embodiment of the method according to the invention, the invention finally also provides that the particulate, in particular dust-like, fuel in the burner with a concentration between 0.1 and 10 kg (fuel) / kg (carrier gas) and / or a conveying speed between 5 and 30 m / s is guided along the burner inner side surface and / or the contact surface and / or the stabilizing ring with sprocket and / or the burner mouth side inner surface region of the fuel tube.

The burner, in particular pulverized coal burner, is preferably designed as a component suitable for an indirect firing system, wherein the fuel-conveying gas has a higher dust load of> 0.4 kg (fuel) / kg (gas).

On the whole, the invention therefore aims at the ignition of solid, particulate, in particular pulverulent fuels based on lignite, Hard coal, biomass or other materials in suitable burner devices, ie in particular burners or pulverized coal burners, without the use of an additional, gaseous or liquid fuel to perform. As a result, the otherwise required infrastructure for the firing of gaseous or liquid fuels or auxiliary fuels can be completely saved. In particular, the invention is suitable for use in indirect combustion systems. Also, existing power plants can be retrofitted with it. Thus, the invention relates to a burner device or a burner, in particular pulverized coal burner, and a method for solid, particulate, especially dusty, fuel with the coal dust or biomass or mixtures thereof without the aid of other gaseous or liquid fuels can be ignited exclusively with electrical energy , For this purpose, the burner device or the burner or pulverized coal burner has in particular the special features or combinations listed below, which are explained below on the basis of the drawing showing an exemplary embodiment. The invention is explained in more detail below by way of example with reference to a drawing.

The drawing, which is a single figure, shows in a schematic sectional view a cross-section of a pulverized coal burner 12 installed in the lining or pipe wall bend of a steam generator of a large thermal power station. This pulverized coal burner 12 comprises a fuel pipe 1 which controls the delivery and concentration of a dusty, carbonaceous fuel conveyed therein in the mouth region 13 of the pulverized coal burner 12 allows where a fuel nozzle 2 is formed, which due to their geometric configuration in the

Fuel delivery cross section 8 funded fuel flow or fuel dust flow completely detected by means of a conventional tooth-shaped stabilizing ring 9, decelerates and deflects. As a result, a sufficient residence time of the fuel in a sufficient concentration in the mouth region 13 of the pulverized coal burner 12, which provides the time for the expiration of the required pyrolysis process in the fuel delivery stream and its ignition. In the mouth region 13, the fuel nozzle 2 has a plurality of windings formed from a heating wire 20 or resistance wire, which form a (first) heating and / or ignition device 14 '. The windings of the heating wire 20 extend through the stabilizing ring 9 and its sprocket 15 and adjacent thereto burner inner side surface portions 16, 17, 18 and 19 of the fuel nozzle 2 and the fuel tube. 1 By means of the heating wire 20 and thus by means of the (first) heating and / or ignition device 14 ', which forms a (first) ignition and / or heat source 3', sufficient for the initiation of the initial pyrolysis process and the ignition of the fuel delivered high heat transfer and heat input initially introduced and registered in these components and structural elements of the burner 12, which then in turn enter the necessary for the initiation of the initial pyrolysis and the ignition of the fuel heat transfer and heat input in the fuel flow past it. Similarly, here is designed as an ignition lance further heating and / or ignition device 14, which forms a further ignition and / or heat source 3 and allows for triggering the initial pyrolysis sufficiently high heat transfer and heat input into the funded fuel flow, with their peak in Area of the forming Zündortes the subsidized fuel arranged. The necessary for the ignition and combustion or oxidation of the fuel oxygen is supplied in particular through the central tube 10 or core air tube 7 in the region of the ignition. Additionally and alternatively, by the fuel in the fuel tube 1 promotional

Carrying gas, for example, an oxygen-containing gas (usually atmospheric air) or a CO2-containing recirculation gas, the oxygen necessary for combustion are supplied to the region of the ignition. The region of the ignition location is in the region of the toothed rim 15 of the stabilizing ring 9. This region of the ignition location is made available via the carrier gas or the oxygen-containing gas or the recirculation gas, the oxygen required for ignition or for immediate oxidation of the pyrolysis products released from the dust particles of the fuel , The here in the field of ignition by means of the (first) heating and / or ignition devices amount of heat generated is introduced directly or at least partially by means of heat conduction and / or heat transfer, for example by means of radiant heat in the fuel nozzle 2 and the stabilizing ring 9 with ring gear 15 and from this via heat conduction into adjacent inner surface areas 16, 17, 18, 19 of the fuel delivery pipe 1 and / or the fuel nozzle 2, so that over a corresponding distance, along which the fuel partially in contact with the inner surface regions 16, 17, 18 19 occurs 19 and flows to the burner orifice 3, for the formation and the course of the initial pyrolysis and ignition in the area the ignition location required heat input is provided in the fuel. Furthermore, it is possible for the heat input necessary for the ignition of the fuel and the initial pyrolysis to be made available exclusively by means of the first heating and / or ignition device 14 '. In this case, however, it is also possible for heat energy to be simultaneously introduced into the fuel by means of the further heating and / or ignition device 14.

The first ignition and / or heat sources 3 'and the further ignition and / or heat source 3 provide - at least in total, but possibly also individually - for the pyrolysis, i. the expiring initial pyrolysis, and the ignition of the particulate, especially dusty fuel necessary heat and ignition energy exclusively by the use of electrical energy as electrically heated ignition and / or heat source 3, 3 'or heating and / or igniter 14, 14' without Use of additional additional liquid or gaseous fuels ready.

After initial ignition of the dust-like fuel and formation of a stable flame, the initial pyrolysis process, ie the formation and execution of the initial pyrolysis, and the initial ignition is completed and / will electrically operated heating and / or ignition device (s) 14, 14 ' switched off. The further combustion of the delivered fuel under continuous flow and continuous formation of the pyrolysis process with the final ignition of the pyrolysis products is then carried out in the usual way by the heat energy input generated by the burner flame in the fuel conveyed in the pulverized coal burner. The heat energy required for the formation and the course of the initial pyrolysis and ignition is introduced in the region of the fuel nozzle 2 and / or the stabilizing ring 9 and the burner mouth side inner surface region 16 of the fuel tube 1 into the fuel flowing along it with sufficient residence time. These surfaces or surface areas form the burner inner side surface 16, 17, 18, 19, along which the amount of heat energy required in the pulverized coal burner 12 for the formation and the course of the initial pyrolysis and ignition at one with a sufficient for the expiration of the initial pyrolysis and ignition Residence time with the flowing fuel in contact or operatively connected brennnnenseitigen surface 16, 17, 18, 19 is introduced into the fuel. This burner inner side surface 16, 17, 18, 19 is wholly or partially part of a contact surface of the (first) heating and / or ignition device 14 ', since the fuel nozzle 2 with the stabilizing ring 9 arranged thereon with ring gear 15 and / or the burner inner surface 16 , 17, 18, 19 by means of the electric heating wire 20 or by means of inductive heating as (first) heating and / or ignition device 14 'is / are formed and the first heated electrical ignition and / or heat source 3' form.

But it is also possible, the heating and / or further ignition device 14 shown in the figure as an electric arc generating device, in particular a plasma torch form, the / on the burner inner side surface and / or the contact surface and / or the thereto is directed past fuel and transfers to this or these the required amount of heat energy. In a manner not shown, the further heating and / or ignition device 14 may also be formed by a hot air conveyor tube, which is equipped to generate the required amount of heat energy with an electric heater and with its burning-side mouth area on the burner inner side surface and / or the contact surface and / or the fuel flowing past it directed and transmits to this or this the amount of heat energy required.

The fuel nozzle 2 comprises a toothed stabilizing ring 9, which is formed and arranged at the mouth-side end of the fuel pipe 1 and forms its mouth end 13. In this case, the fuel nozzle 2 and in particular the toothed stabilizing ring 9 is further arranged with or in a - desired, certain and possibly determinable - distance before the mouth of the concentric fuel tube 1 within the same and arranged in the center of the burner core air tube 7 and formed.

The fuel nozzle 2 and / or the burner inner surface areas 16,

17, 18, 19 are wholly or partially at least substantially, preferably exclusively, electrically heated to a temperature of at least 200 ° C, depending on the nature of the fuel to a temperature of preferably> 400 ° C. Due to the, preferably complete detection, deceleration and deflection of the fuel dust stream in the axial and radial flow direction, sufficient dwell time for the pyrolysis of the dust particles of the fuel stream is produced at the fuel nozzle 2, and the preferably completely detected and delayed dust particles are heated in such a way that they degas and releasing flammable pyrolysis products, wherein this pyrolysis process is initiated and maintained prior to the initial ignition of the fuel and thus of the burner 12 exclusively by means of heat energy from the electrically heated fuel nozzle 2 and / or the electrically heated burner inner surface 16, 17, 18th , 19 and / or the electrically heated ignition and / or heat sources 3, 3 ', in particular the stabilizing ring 9 with ring gear 15, is provided.

The further ignition and / or heat source 3 preferably supports the pyrolysis and (de) ignites pyrolysis products which have become free, and if appropriate in addition, if, for example, the electrically heated burner interior surfaces 16, 17,

18, 19 of the fuel nozzle 2 or the stabilizing ring 9 is electrically heated in another way, for example, inductively or by means of a sunk in the fuel nozzle 2 heating wire 20th In a non-illustrated embodiment of the invention can be provided here that is used as a further heat source 3, a plasma flame, which can be generated by means of electrical energy without an additional fuel. The plasma flame is thereby formed with the aid of a suitable lance in the immediate vicinity of the fuel nozzle 2 and / or the stabilizing ring 9, whereby the fuel dust / fuel dust is heated so much that the pyrolysis process is instantaneous and the oxidation can take place in a timely manner. This ignition and / or heat source 3 in the form of a plasma flame can additionally be provided if the fuel nozzle 2 and / or the burner inner side surface 16, 17, 18, 19 in other ways completely or partially electrically heated, for example, inductively or by means of a In this case, the fuel dust / fuel dust is additionally strongly heated by the formation of the plasma flame with the aid of the suitable lance in the immediate vicinity of the fuel nozzle 2, in the fuel nozzle 2 and / or in the burner inner side surface 16, 17, 18, 19 the pyrolysis process is supported and the oxidation of the pyrolysis products released from the fuel dust particles at the electrically heated fuel nozzle 2 or the burner inner side surface 16, 17, 18, 19 or the ignition and / or heat sources 3, 3 'can take place in a timely manner.

Furthermore, the fuel tube 1, a device 4, with the temporary startup dust lock can be formed, which is specifically directed to increase the heat release in the ignition and / or heat sources 3 and / or 3 ', and then after ignition to be dissolved again without worsening the above-mentioned ignition conditions. The device 4 may be designed as a rail, which stacks the fuel dust with the help of a swirl generator 5 at a certain circumferential position and deflects in the axial direction.

In principle, it is possible that for the exclusive or additional provision of a sufficient ignition temperature and to ensure sufficient pyrolysis or in support of the pyrolysis, an electrically heated heating wire 20 or another form of electrical heating, For example, inductive heating, as ignition and / or heat source 3, 3 'in the fuel nozzle 2 and / or in the burner inner surface 16, 17, 18, 19 is integrated. The exclusiveness results when only at this point an ignition and / or heat source 3, 3 'is formed. The additionality arises when such or one of the heat source 3 is also formed elsewhere in the burner.

Furthermore, a fuel lance 6 is arranged in the burner 12, which selectively introduces a part of the fuel / fuel dust / fuel dust into the further ignition and / or heat source 3, which is then preferably designed as a plasma flame, as a result of which the carbonaceous dust particles are heated very strongly and the release and ignition of pyrolysis products from the fuel leads to the formation of a flame which, in turn, causes the pyrolysis of the dust-like fuel particles detected and delayed at the fuel nozzle 2 by heat release and in particular by the heat radiation of the heated fuel particles continuously emitted via the electromagnetic spectrum. The fuel lance 6 can be formed as an independent component or as a further ignition and / or heat source 3 surrounding annular cross-section.

However, it is also possible to initiate other dust-like, not combustible media, by means of a suitable lance 6 or a lance of the further ignition and / or heat source 3 surrounding ring cross section in the further ignition and / or heat source 3 instead of fuel dust that thereby the effect of the pyrolysis of the detected at the fuel nozzle 2 and delayed

Fuel dust particles promoting heat radiation of these dust particles is achieved.

The fuel nozzle 2 can be isolated on its side facing away from the fuel flow with the aid of refractory materials, such as textiles or dimensionally stable components made of ceramic fibers, in order to reduce the heat losses to the surrounding the fuel pipe 1 shell air 1 1 and the electrical energy requirement of the heating. In particular, the fuel nozzle 2 is heated in particular inductively to a suitable and the respective intended temperature.

It is also possible to provide an ignition lance 6 operated with a dusty, solid fuel and designed as a heating and / or heat source, which generates a flame in the vicinity of the fuel nozzle 2, preferably with the aid of an electric igniter with the addition of pure oxygen or a gas mixture is ignited with very high oxygen partial pressure. Since the formation of a plasma flame as a further ignition and / or heat source 3 technically possibly requires a relatively high constructive and / or equipment expense, it can be provided that the ignition is performed by means of sufficiently hot air or at least supported. This is possible because the ignition of the coal dust is ultimately due to the pyrolysis of the volatiles and the subsequent onset of the reaction of the volatiles with the supplied oxygen. Crucial for this are the temperature conditions in the area of the mixing zone between this hot air and the fuel and the residence times. Hot air temperatures of> 450 ° C, for example, a hot air generated by means of an electric heating and / or ignition device 14 with a temperature in the range of 650 ° C, are sufficient to set the pyrolysis and ignition process, for example in dry lignite in motion.

Such a heating and / or ignition device 14 may for example be installed in the burner shown in the figure. The hot air is then introduced in the region of the mouth 13 of the dust nozzle or burner nozzle 2 and mixed there with the particular dust-like fuel, preferably lignite dust. This ignitable mixture is then located directly in the region of the return flow zone of the burner, so that the resulting after the ignition of the fuel flame at a correspondingly high swirl over the circumference of the

Brenners is distributed and forms a stable flame. In principle, this method can be used in any burner form in which the mixing zone between fuel and air or combustion oxygen or oxidizing agent in the region of a flame holder, here the stabilizing ring 9, located. The hot air is mixed into the fuel in the burner inside initial region of the mixing zone between fuel and air. In this case, the speed of the fuel should be so low that on the remaining way to the burner mouth good mixing of the hot air is ensured with the fuel with sufficient residence time.

To generate the hot hot and / or ignition air can be provided as a further ignition and / or heat source 3, a hot air tube through which the heated ignition air is promoted and thereby heated by means provided in or on the hot air tube electrical heating within the hot air tube. The outlet of the hot air tube is located near the dust nozzle or fuel nozzle 2 within the burner in the flow direction in front of the stabilizing ring 9, so that an immediate mixing of the hot air can be done with the supplied through the fuel tube 1 fuel. In this case, the hot air tube can be guided by the primary air tube provided at the burner, the core air tube 7, by the secondary air tube, the jacket air pipe or from all sides to this point. The intended for heating electrical device is to allow heating of the air to sufficiently high temperatures for the heating and pyrolysis of the fuel. The positioning thereof within the burner is preferably chosen so that this is possible with little design effort.

The heated ignition air can also be mixed directly with a dusty medium, preferably fuel dust, with the help of a lance 6 or a surrounding the Zündluftlanze ring cross section, so that a high

Heat radiation of the then hot dust particles leads to a heat transfer to the detected and delayed at the fuel nozzle dust particles, causing them to degas and release flammable pyrolysis. The invention enables the conversion of boilers or steam generators

Ignition and support fire with existing combustion of coal dust, in particular dry lignite dust, and is particularly advantageous in indirect firing and a concomitant dismantling of the supply infrastructure for oil or gaseous fuels. A such, in particular indirect firing may also include mixtures of the different fuels. It is expedient to use a mixture of dry brown coal and sawdust or other biomass. The firing and support firing based on the indirect firing can also be used in steam generators with direct main firing of hard coal or lignite coal and allows here in particular the operation of the steam generator at arbitrarily low loads with nevertheless stable firing. Indirect firing is expediently carried out with higher dust loads> 0.4 kg (fuel dust) / kg (gas).

Under direct firing or direct firing system is understood in the above context and in connection with the invention that the fuel after its preparation / grinding in a grinding plant, especially coal mills, directly to the burners in the firing chamber of the large steam generator is supplied. Indirect firing or indirect firing system is understood to mean an intermediate storage of the fuel after the treatment / milling in the grinding plant in one or more storage containers or silos, from which the fuel is then conveyed to the burners as needed and as needed, if appropriate later.

In principle, the combustion of pulverized fuel is used in the steam generators of thermal power plants. The steam generators are equipped with pulverized coal burners 12 for this purpose. The pulverized coal burners 12 fulfill the function of enabling the pyrolysis and combustion process described below.

The burning of solid, dusty fuel, such as coal dust, requires its initial ignition or ignition. Combustion means that energy is released by oxidation of the combustible constituents present in the fuel. However, very specific conditions have to be fulfilled for the ignition of the fuel. If these are not fulfilled, the fuel does not ignite and the energy chemically bound in it is not released. Since the oxidation of the carbon fixedly bound in the fuel requires a high initial thermal energy, the volatile constituents contained in the fuel are initially ignited when the fuel is ignited. In order for these to be ignited, they must gaseously escape from the fuel dust. Under the influence of heat, the volatiles escape from the fuel dust and thus come into contact with the oxygen necessary for the oxidation. The escape of the volatiles into the gas phase is referred to as pyrolysis. In a continuous combustion process, the heat required for the individual process steps originates from the energy release of the exothermic combustion reactions. However, to initialize a continuous combustion process, heat energy must first be provided from a (different) source to initiate the process. For this purpose, usually initially a gaseous or liquid fuel is burned. By the invention is achieved, the combustion of gaseous or liquid fuels, which are otherwise necessary for the ignition of a solid, dusty fuel, save. As individual process steps of the pyrolysis and combustion process

1 . Supply of fuel and oxidant gas

2. Allowing residence time and heat transfer to the fuel

3. Provision of oxygen 4. Initialization of the pyrolysis and combustion process

4a. Heating up fuel nozzle 4b. Use of a plasma torch 4c. Other heat sources 5. Pyrolysis 6. Combustion of pyrolysis products

7. combustion of carbon 8. Training a flame explained in more detail below.

1 . Process step: supply of the fuel and the oxygen carrier gas

It is transported in fuel lines leading by means of a carrier gas of pulverized fuel to a burner 12. Additionally, additional conduits carry air or other oxidant gas into the combustor 12 to provide an amount of oxygen necessary for combusting volatiles and carbon in the fuel. Also, the carrier gas of the fuel in the fuel lines may contain oxygen. The concentration of fuel in the carrier gas may be, for example, between 0.1 and 10 kg (fuel) / kg (carrier gas). The conveying speed of the fuel can be in the range between 5 and 30 m / s. The pyrolysis and combustion process takes place at the mouth region 13 of the burner 12, i. where the fuel and oxygen carrier gas leading tubes of the burner 12 open into the furnace of a steam generator. 2nd step: Allowing residence time and heat transfer to the fuel

In addition, the burner 12 fulfills the function of allowing for the heat transfer to the fuel and the formation and the pyrolysis necessary residence time. The residence time depends on the required amount of heat or temperature of the fuel and on a

Heat transfer to the heat acting on the fuel. This is realized in the burner 12 in that the amount of heat or the temperature corresponds to the requirements of the pyrolysis and the initialization of the oxidation of volatile constituents of the fuel. A high residence time ensures sufficient heat transfer. This is due to the structural design of the

Burner 12 is increased by the dusty fuel at a suitable location at the mouth region 13 of the burner 12 or in its vicinity by deceleration, deceleration, turbulence or deflection in its movement is influenced such that the available and acting on the fuel heat output leads to a sufficient transfer of heat, which is required for the initiation of pyrolysis and the combustion of the pyrolysis on the fuel. The component realized for influencing the movement of the fuel in the burner 12 is the fuel nozzle 2 or the flame holder. The necessary amount of heat must be provided at the appropriate place mentioned above. At the same time, the residence time is selected such that an ignitable mixture of gaseous pyrolysis products and the oxygen carrier gas is produced by the pyrolysis.

3rd process step: provision of oxygen

The carrier gas, which transports the fuel dust, may already contain an amount of oxygen sufficient for the oxidation of the pyrolysis products. Should it be advantageous or necessary from a process engineering point of view to set a low oxygen concentration in the carrier gas or to use an inert gas as a carrier gas, the burner 12 may alternatively via lines for providing air or other oxidant gases, the required oxygen at its mouth for the combustion of the provide gaseous pyrolysis or for the subsequent combustion of the carbon contained in the fuel have. The mouth of the burner inside pipes is located where the amount of oxygen required for combustion must be made available.

4. Process step: Initialization of the pyrolysis and combustion process To initialize the entire pyrolysis and combustion process must to

Beginning of the continuous supply of dusty fuel heat to be transferred to the fuel. In this case, in the prior art usually a gaseous or liquid auxiliary fuel is first ignited electrically, ie by a spark or arc is an ignitable mixture of oxygen carrier gas and gaseous or liquid fuel for a short time supplied heat energy sufficient to achieve an oxidation of the auxiliary fuel. The oxidation or combustion of the auxiliary fuel liberates thermal energy, which results in a continuous flow Combustion of the supplied liquid or gaseous fuel leads. The heat energy released from this combustion is used to ignite a dust-like fuel, ie to effect the initial pyrolysis and ignition of the dust-like fuel. Once the dusty fuel is ignited and burns, the combustion of the liquid or gaseous auxiliary fuel can be stopped because the combustion of the dust-like fuel continues automatically by the heat released during combustion heat. For the ignition of dusty fuel, a short-term spark or arc is insufficient to cause pyrolysis, ie, the escape of volatiles from the fuel with the aim of producing a combustible mixture with an oxygen carrier.

The invention now provides a method and a pulverized coal burner 12 which exclusively generates and supplies the amount of heat required for the pyrolysis and the combustion of the volatile constituents of the pulverulent fuel without combustion of an additional liquid or gaseous auxiliary fuel.

5. Process Step: Pyrolysis Pyrolysis, ie the escape of volatiles from the dusty, solid fuel, already begins at temperatures lower than those required to oxidize the carbon fixed in the fuel. The so-called pyrolysis temperature is dependent on the properties of the dust-like fuel and can be determined experimentally. For the pyrolysis of the volatile constituents of the fuel, it is necessary that there is a sufficient residence time, during which a sufficient amount of heat can be introduced into the fuel, which allows the fuel is heated so that the formation and implementation of the initial Pyrolysis required temperature is reached. For this purpose, at least the first heat source 3 'adapted to the available residence time is provided, which is optionally supported by the further heat source 3. If there is an insufficient residence time or amount of heat, so that the initial pyrolysis can not be effected, the combustion of the solid fuel will not take place. 6th step: combustion of the pyrolysis products

The gaseous, derived from the fuel volatiles ignite under certain conditions. On the one hand, sufficient oxygen must be available for combustion. In addition, a suitable combustion ratio of oxygen and combustibles, i. an ignitable mixture of the oxygen carrier gas and the volatiles escaping from the fuel are formed. The ability of the mixture to ignite is described by means of the lower and upper ignition limits. The ignition limits are those mixture ratios of oxygen and combustible materials within which such a mixture is flammable. It must therefore initially escape a sufficient amount of volatile components from the fuel, so that ignitable mixtures arise. The residence time already mentioned above is therefore designed so that a sufficient amount of volatiles escapes from the fuel. In addition, sufficient oxygen is provided to form an ignitable mixture. This means that the supply of air or another oxidizer is designed such that the escaped volatiles and the oxygen carrier gas form an ignitable mixture. Furthermore, a sufficient temperature must predominate for an ignition of the mixture or a sufficient temperature

Dwell time for heating up to this temperature or in other words a sufficient residence time for the required transfer of heat allows. If this is the case, then, after successful ignition of the mixture, heat energy is released from the exothermic oxidation reactions.

7. Process step: combustion of the carbon

The heat energy released from the combustion of the educt mixture of oxygen carrier gas, eg air, and the volatiles released from the fuel leads to an increase in the temperature of the products resulting from the combustion and to a further heat transfer to the degassing fuel. The combustion of volatile constituents and the degassed fuel (residual coke) in turn leads to a release of heat energy, which causes the formation of a stable, continuous Combustion process allows. The combustion of the degassed fuel is largely determined by chemical and diffusion processes.

8. Process Step: Forming a Flame By the released heat energy from the combustion of the volatile constituents and the residual coke, a temperature increase of the gaseous and solid constituents of the flue gas mixture, i. the combustion products causes. Due to high temperature fuel, dust and soot particles, radiant energy is emitted to the environment by electromagnetic radiation in the area of heat radiation and also in the area of visible light. In this way, finally, a visible flame is created. Gaseous products of the combustion reactions with a heteroatomic structure also emit heat radiation in certain wavelength ranges and thus lead to heat transfer by radiation. In addition, a recirculation of hot flue gas within the visible flame can be achieved by a skillful guide the flow of combustion air or other oxygen carriers. This causes a convective heat transfer to the educts of the combustion. Together with the radiant heat transfer described above, the reactants continuously fed to the combustion, i. the dusty fuel and the volatiles escaping from it, heated up. This results in a continuous combustion, wherein the supplied fuel is degassed by absorbing heat, ignites and burns. To initialize the pyrolysis and combustion process, the for the

Initialization of the individual process steps necessary heat are first provided by a source other than the exothermic combustion reactions. It is therefore below in the context of the invention

Process steps for initializing the pyrolysis and combustion process described. Process step 4a: Ignition on hot surfaces

The amount of heat necessary for the initialization of the process steps of pyrolysis and ignition of the fuel, ie for providing the activation energy of the exothermic volatile oxidation reactions, on a suitable surface, at which the residence time for heat transfer is sufficient, burner inside provided within the burner 12. The residence time necessary for the formation and the course of an initial pyrolysis and ignition of the dusty fuel, necessary residence time for heating can be achieved constructively by internals that delay the fuel, decelerate, distract or vortex. These fittings or surfaces may be the fuel nozzle 2 with the toothed stabilizing ring 9 or a flame holder. Since the fuel is influenced in its movement by the fuel nozzle 2 and / or the toothed stabilizing ring 9 (also referred to as a flame holder), the residence time required for the individual process steps is realized on this component. It is therefore expedient to transfer the amount of heat required for the abovementioned process steps to the fuel also at this suitable surface. This can be done by the fuel nozzle 2 and / or the stabilizing ring 9 is electrically heated to a temperature above 200 ° C. The temperature of the fuel nozzle 2 or of the stabilizing ring depends on the specific requirements of the respective fuel to be pyrolyzed and ignited. By convective heat transfer, heat conduction and heat radiation, an amount of heat is transferred from the hot surface to the fuel, which is sufficient to allow the necessary process steps described above. After successful ignition of the fuel, ie, with continuous combustion of the supplied fuel, the heating of the fuel nozzle 2 and / or the stabilizing ring 9 and / or the heat-transmitting surfaces of the burner 12 is terminated, since then from the combustion process itself required for the individual process steps amount of heat is available. That is, the first ignition and / or heat source 3 'and the other ignition and / or heat sources. 3 forming and / or thus in thermally conductive operative connection standing first heating and / or ignition device 14 'and the other heating and / or ignition device 14 are turned off or turned off. Process step 4b: Use of a plasma torch

The amount of heat necessary to achieve the pyrolysis of the fuel and to activate the oxidation of the pyrolysis products may also be provided by means of a plasma torch. This occurs at a point at which the fuel has a sufficient residence time, so that sufficient heat can be transferred to the fuel. The use of a plasma flame with the aim of avoiding the combustion of gaseous or liquid fuel for the ignition of solid, dusty fuel, can go beyond the mere making available of heat, since a plasma has special chemical-physical properties. The formation of a plasma is particularly suitable for the initialization of the firing of solid, dusty fuels, because the charge carriers present in the plasma, namely radicals, ions and electrons, can trigger the chemical reactions generally referred to as combustion. The plasma flame is aligned by means of a lance at a suitable location near the burner mouth so that a sufficient transfer of heat to the fuel for the above-mentioned process steps, which require the supply of heat, or the dust-like fuel in direct contact with the free charge carriers present in the plasma come, so that the combustion can take place. In a

Plasma flame is very high temperature, ie the charge carriers present in the plasma have a high kinetic energy, so that a suitable heat transfer to the fuel to effect the pyrolysis and the combustion of pyrolysis products takes place. Likewise, charge carriers for combustion reactions with the constituents of the dusty fuel are available in the plasma. If the other conditions described above for the individual process steps are also met, the fuel can be ignited and burned in this way. Once the ignition of the fuel is realized in this way, the ignition of the Maintaining fuel with the heat available from the combustion, so that the generation of the plasma can be switched off again.

It is possible, in order to ensure a suitable heat transfer to the fuel or to bring the fuel directly into contact with the charge carriers present in the plasma, to introduce a partial flow from the main flow of the fuel in a separate fuel-carrying lance directly into the formed plasma flame, so that the high temperatures or the charge carriers present in the plasma under the provision of oxygen, for example in the fuel carrying gas in the flame immediately a combustion of dust-like fuel, ie volatiles and fixed carbon takes place. This plasma-assisted pulverized coal flame leads to combustion of the pulverized coal, in which, according to the energy released from the plasma flame and the combustion and the resulting temperatures of the combustion educts and products, heat radiation is released to the environment. By the heat transfer by radiation from this flame then the main flow of the fuel can be ignited according to the aforementioned process steps on the burner.

It is also possible to introduce another solid, non-combustible, dust-like material in the plasma flame, whereby this material undergoes a strong increase in temperature and then emits thermal radiation according to its temperature. Such a particle flame made of non-combustible material is suitable for transferring heat to the fuel stream, so that the individual method steps of the ignition are made possible.

The initiation of the process steps pyrolysis and combustion of the pyrolysis by the provision of a sufficient amount of heat energy can in the plasma flame and the plasma-based Kohlenstaubflamme from a partial flow of the fuel and the particle flame with non-combustible material with other heat sources, such as a heated fuel nozzle or a heated flame holder, combined. Process Step 4c: Other heat sources

Besides a heated surface and the formation of a plasma, it is also possible to use another heat source. For example, by means of a suitable lance, a hot gas, for example air, with a temperature of at least 200 ° C can be introduced at a suitable location, so that there is sufficient heat transfer by conduction, radiation and convection to the fuel to the pyrolysis of gaseous components trigger. The hot gas can be heated, for example by means of an electric heater.

In order to support the heat transfer to the fuel by radiation, it is conceivable to introduce fuel dust or non-combustible dust directly into the hot gas.

Claims

claims

1 . Burner, in particular pulverized coal burner (12), comprising a fuel tube (1), a fuel nozzle (2), at least one ignition and / or heat source (3 ') and a tube (7, 10) carrying an oxygen-containing gas and / or recirculated flue gas , wherein the at least one ignition and / or heat source (3 ') arranged on the burner inside and as an electric heating and / or ignition device (14') is formed or includes those within the burner for the formation and the process of the needed initial pyrolysis and ignition

Generated amount of heat energy burner inside, especially in the field of forming fuel-ignition, exclusively by converting electrical power into heat energy and / or provides, characterized in that a stabilizing ring (9) with sprocket (15) part of the

Mouth region (13) of the fuel nozzle (2) arranged electrical heating and / or ignition device (14 ').

2. Burner according to claim 1, characterized in that the toothed stabilizing ring (9) is arranged at a distance in front of the orifice of the concentric within the fuel tube (1) and in the center of the burner tube (7, 10).

3. Burner according to claim 1 or 2, characterized in that the fuel nozzle (2) is designed such that the tooth-shaped

Stabilizing ring (9) is designed to be directed radially inward and detects, delays and deflects a fuel flow or fuel dust flow delivered in a fuel delivery cross section (8).

4. Burner according to one of the preceding claims, characterized in that the fuel nozzle (2) and / or the Stabilization ring (9) with sprocket (15) at least one of electric current flowable heating wire (20) and / or at least one inductively heated area / has, which in each case within the burner for the formation and the course of the initial pyrolysis and Ignition generated / generate and provide / provide heat energy amount.

Burner according to one of the preceding claims, characterized in that the burner has a burner inner side surface (16, 17, 18, 19) and / or the electric heating and / or ignition device (14 ') has a contact surface / with such or in thermally conductive and / or heat-transfer active compound is / are in the startup operation of the burner with a sufficient for the expiration of the initial pyrolysis and ignition residence time with the fuel in the fuel pipe (1) funded fuel in contact or in operative connection / stand.

Burner according to Claim 5, characterized in that a fuel nozzle (2) having a heat-conducting and / or heat-transmitting operative connection to the stabilizer ring (9) with toothed rim (15) has the inner surface area of the fuel tube (1) on the burner inner side (16, 17, 18, 19) and / or the contact surface is formed.

Burner according to claim 5 or 6, characterized in that the burner inner side surface (16, 17, 18, 19) is wholly or partly part of the contact surface of the heating and / or ignition device (14 ').

Burner according to one of the preceding claims, characterized in that the fuel nozzle (2) in the mouth region (13) more of a heating wire (20) or resistance wire formed Has windings, which form the heating and / or ignition device (14 ').

Burner according to Claim 8, characterized in that the windings of the heating wire (20) extend through the stabilizing ring (9) and its toothed rim (15).

Burner according to claim 8 or 9, characterized in that the windings of the heating wire (20) by the stabilizer ring (9) with ring gear (15) adjacent burner inner surface regions (16, 17, 18, 19) of the fuel nozzle (2) and Fuel tube (1) extend.

Burner according to one of the preceding claims, characterized in that the fuel nozzle (2) and / or the stabilizing ring (9) with toothed rim (15) form the electrical heating and / or ignition device (14 ').

Burner according to one of the preceding claims, characterized in that the fuel nozzle (2) and / or the stabilizing ring (9) with toothed rim (15) and / or the burner inner side surface areas (16, 17, 18, 19) to a temperature of at least 200 ° C, in particular of> 450 ° C, preferably of between 600 ° C - 700 ° C, is formed heatable / are.

Burner according to one of the preceding claims, characterized by ignition and / or heat sources (3, 3 ') which generate a combination of the electric current into heat energy converting heating and / or ignition device (14') with an arc generating or a hot air generating , form another heating and / or ignition device (14).

14. Burner according to claim 13, characterized in that the further electrical heating and / or ignition device (14) comprises or forms a plasma torch, in particular directed to the burner inner side surface (16, 17, 18, 19) and / or the contact surface is and transfers heat energy to these and / or the subsidized fuel.

15. Burner according to claim 13, characterized in that the further electrical heating and / or ignition device (14) comprises or equipped with an electric heater equipped hot air conveying tube, with its burner inside mouth region on the burner inner surface (16, 17, 18, 19) and / or the contact surface and / or the stabilizing ring (9) with toothed rim (15) is directed and transmits heat energy to these and / or the subsidized fuel.

16. Burner according to one of the preceding claims, characterized in that the electrical heating and / or ignition device (14 ') and / or the further electrical heating and / or ignition device (14), in particular during start-up of the burner, within the Brenners needed for the formation and the course of the initial pyrolysis and ignition

Amount of heat energy in the region of the fuel-ignition site that is being formed without the use of another additional liquid, gaseous or solid fuel, except for the fuel that is initially to be pyrolyzed and ignited, and / or provide / provide.

17. Burner according to one of the preceding claims, characterized in that the stabilizing ring (9) with toothed rim (15) is at least part of an ignition and / or heat source (3 ').

18. A method for igniting a particulate, in particular dusty, fuel by means of a burner, in particular A pulverized coal burner (12) according to any one of claims 1-17, wherein the fuel in the burner to its within the burner in the region of the fuel nozzle (2) is formed promoting ignition and the startup of the burner for the formation and the course of an initial pyrolysis and the ignition of the fuel supplied to the burner mouth (13) is introduced into the burner and / or the fuel conveyed therein exclusively by means of at least one ignition and / or heat source (3 ') disposed in the burner, which heat source (3') is in Form of a heating and / or ignition device (14 ') is formed in the burner or with such arranged in the burner heating and / or ignition device (14') in heat-conducting and / or heat-transmitting active compound, the required amount of heat energy only by conversion electrical Electricity is generated and / or provided in heat energy on the burner interior side,

characterized,

in that the required amount of heat energy is introduced into the burner and / or into the conveyed fuel by means of a heating and / or ignition device (14 ') arranged in the opening region (13) of the fuel nozzle (2), the component of which comprises a stabilizing ring (9) with toothed rim (14). 15).

A method according to claim 18, characterized in that the heat energy required during start-up of the burner within the burner for the formation and the course of the initial pyrolysis and ignition without the use of another additional liquid, gaseous or solid fuel, except for the initial pyrolyzing and to be ignited Fuel is generated.

A method according to claim 18 or 19, characterized in that the amount of heat energy required within the burner for the formation and the course of the initial pyrolysis and ignition at a sufficient time for the expiration of the initial pyrolysis and ignition residence time with the flowing fuel in contact or in Actively connected burner inside surface (16, 17, 18, 19) of the burner is registered in the fuel and / or on a contact surface of the heating and / or ignition device (14 ') burner inside is registered in the fuel, with a for the entry the amount of heat energy required in the fuel for

Generation of the initial pyrolysis and ignition sufficient residence time is inside the burner with the fuel in contact or in operative connection, wherein the surface (16, 17, 18, 19) and / or the contact surface of the fuel nozzle (2) and / or the stabilizing ring (9) with sprocket (15) is formed or include / include.

Method according to one of Claims 18-20, characterized in that the fuel nozzle (2) and / or the stabilizing ring (9) has / has a heating wire (20) which can be flowed through by electric current or an inductively heated region, by means of which in each case the inside of the Burner is generated and provided for the formation and the course of the initial pyrolysis and ignition required amount of thermal energy.

22. The method according to any one of claims 18 - 21, characterized in that the burner inner side surface (16, 17, 18, 19) and / or the contact surface and / or the stabilizing ring (9) with sprocket (15) and / or a brennermündungsseitiger Inner surface area of the fuel tube (1) by means of the heating and / or ignition device (14, 14 ') to a temperature of> 200 ° C, in particular of> 450 ° C, preferably between 600 ° C - 700 ° C, is heated.

Method according to one of claims 18 - 22, characterized in that the particulate, in particular dust-like, fuel in the burner with a concentration between 0.1 and 10 kg (fuel) / kg (carrier gas) and / or a conveying speed between 5 and 30 m / s on the burner inside surface (16, 17, 18, 19) and / or the Contact surface and / or the stabilizing ring (9) with sprocket (15) and / or the burner mouth side inner surface area of the fuel pipe (1) is guided along.