RU2282105C2 - Solid fuel burner (variants), fuel combustion device (variants), boiler (variants), fuel combustion method (variants), boiler system and power plant (variants) - Google Patents

Abstract

FIELD: power engineering, particularly burners for combustion of pulverulent fuel.

SUBSTANCE: solid fuel burner comprises central air supply pipe adapted to eject air, fuel atomizer located outside the central air supply pipe and adapted to eject fluid mixture including solid fuel and conveyance gas, additional vent orifices or pipes to supply additional air flow and one or several ambient air supply pipes. The additional vent orifices or pipes are formed on inner fuel atomizer and used for air ejection. The ambient air supply pipes are located outside fuel atomizer and used to eject air for fuel combustion. Outlet of any or determined central air supply pipe or additional vent orifice or pipe is located upstream of fuel atomizer outlet along process chain of the burner. Heated and/or compressed air is supplied to above additional vent orifices or pipes. Obstruction is created on outer surface of above central air supply pipe beginning from upstream side along process chain of the burner. The obstruction has conical part with diverging cross-section and conical part with converging cross-section. Restricted channel section is created on inner wall of fuel atomizer and is adapted to narrow fuel atomizer channel beginning from upstream side along process chain of the burner and to widen above channel to initial channel dimension. Guiding means to direct ambient air to be ejected is installed at ambient air supply pipe outlet. Pipe widening member is installed at ambient air supply pipe outlet. The widening member is adapted to increase ambient air flow twisting at above pipe outlet to provide air flow ejection at angle of 45° or less with regard to central burner axis. Annular flame stabilizer is located between fuel atomizer and ambient air supply pipe. The flame stabilizer is located opposite to solid fuel and air mixture to be ejected.

EFFECT: reduced nitrogen oxide concentration in exhaust gas flow.

55 cl, 32 dwg

Description

The invention relates to a solid fuel burner and a combustion method using a solid fuel burner for burning solid fuel transported by an air stream; and in particular to a solid fuel burner and a combustion method using a solid fuel burner that are applicable over a wide load range of the combustion chamber and therefore suitable for burning fuel, for example, pulverized coal, wood and peat, saturated with moisture and volatile substances, and additionally providing the possibility of burning, by reducing the concentration of nitrogen oxides (No _x ) in the exhaust gas; to a device for burning fuel, for example, a combustion chamber, a heating furnace and a blast heater, using said burner and a method for controlling them; to a solid fuel boiler and the system in which it is used; and to a coal-fired power plant.

In recent years, environmental regulations have been tightened to protect the environment. In particular, for the aforementioned type of pulverized coal boilers, a reduction in the generation of NO _x in the exhaust gas (reduction in the concentration of NO _x ) is seriously required for coal combustion. As combustion technologies, two-stage combustion methods (NO _x reduction technologies) are known to reduce the concentration of NO _x generated in the exhaust gas. Two methods of two-stage combustion are known. One method aims to reduce the generation of NO _x in the combustion chamber as a whole, while the other method aims to reduce the generation of NO _x in one burner. In the method that ensures a reduction in the concentration of NO _x in general, the air coefficient (the ratio of the amount of air supplied to the amount of air needed to completely burn the amount of fuel) in the active combustion zone in the combustion chamber is maintained below unity. In this fuel saturated zone, the generated NO _{x is} chemically reduced and, therefore, a reduction in the NO _x concentration is achieved. Unburned carbon resulting from the use of this method is completely burned with the help of air introduced through the air intake, which is provided downstream from the active combustion zone.

In the method of decreasing NO _x generation by a single burner operating on solid fuel (just a burner, in some cases described below), for example, a burner operating on pulverized coal, the secondary and tertiary air are twisted, thereby delaying its mixing with the flow pulverized coal combusted with one primary air. Due to this, a large area of chemical reduction is formed (such burners are referred to below as burners providing a reduced concentration of NO _x ). This method is implemented in a pulverized coal burner with a reduction in NOx concentration (in Japanese Unexamined Patent Publications No. Sho-60-176315 and No. Sho-62-172105).

These technologies reduce the NOx concentration in the exhaust gas to a value of 130 ppm (fuel coefficient = bonded carbon / volatile matter = 2, nitrogen in coal = 1.5%, and unburned carbon in ash = 5% or less). Nevertheless, the regulated value of the concentration of NO _x in the exhaust gas decreases year by year and the required value of the concentration of NO _x in the exhaust gas in the near future is 100 ppm or less.

Burners have been developed that provide a reduced concentration of NO _x in the exhaust gas, capable of reducing the generation of NO _x to 100 ppm or less. Such burners include a burner having an internal ring flame stabilizer designed to enhance the combustion process with a reduced concentration of NO _x in the active combustion section; and a burner having an annular flame stabilizer for forming a jumper between the inner annular flame stabilizer, as described above, and an external annular flame stabilizer provided in the outer periphery of the fuel atomizer, through which a mixture of pulverized coal and carrier gas passes.

Incidentally, in geological areas where an increase in energy demand is expected, most consumers in the near future will use low-grade coal, which is characterized by a rich moisture and ash content and low calorific value. Among various low-grade coals, coal with a high moisture content, for example brown coal and semi-bituminous coal, is found in abundance. However, compared to coal, such coal has the problem of poor fuel, for example, low flame temperature and poor flammability. Brown coal is found mainly in Europe and is a juvenile coal containing 20% or more ash and 30% or more moisture.

In addition, low-grade coal (for example, brown coal and lignite), wood and peat are rich in volatile substances, which when released are released in the form of gas, and are also rich in moisture. Such fuels have a lower calorific value than high-grade coal, such as coal and anthracite, and are also difficult to grind. In addition, the ash of such fuels has a low melting point. The rich content of volatile substances simply causes spontaneous combustion during storage and during grinding in air. Compared to coal or similar fuels, this causes processing difficulties. To prevent the occurrence of these difficulties in the grinding and burning of brown coal and lignite, a mixture of exhaust gas and air is used as the fuel transporting gas. Since this gas mixture has a lower oxygen concentration, spontaneous ignition of the fuel is prevented. In addition, the residual heat in the exhaust gas contributes to the evaporation of moisture in the fuel transported by the gas mixture.

However, since the fuel is transported by gas with a low oxygen concentration, the combustion reaction does not develop until the fuel ejected from the burner is mixed with air. That is, the combustion reaction is limited by the speed of mixing fuel with air. This leads to a lower burning rate than the burning rate of coal, which can be transported by air. Accordingly, the time required for combustion is longer than for coal. This causes an increased content of unburned carbon at the outlet of the combustion chamber.

The method of accelerating the ignition of fuel transported by a transporting gas with a low oxygen concentration should provide air to the end of the fuel atomizer so as to increase the oxygen concentration in the gas transporting the fuel. For example, Japanese Unexamined Patent Application Publication No. Hei-10-73208 describes a burner having an air supply tube outside the fuel atomizer. In addition, to accelerate the mixing of fuel with air at the outlet of the fuel atomizer, a burner is usually used having an air supply tube in the center of the atomizer.

In addition, Japanese Patent Application Publication No. Hei-4-214102 discloses a burner comprising a fuel atomizer for ejecting a mixture of pulverized coal and a carrier gas; and a secondary air supply pipe and a tertiary air supply pipe provided outside the fuel atomizer; in which an annular flame stabilizer, designed to maintain the flame of pulverized coal ejected from the fuel atomizer, is provided at the end of the partition between the fuel atomizer and the secondary air supply pipe.

As indicated above, brown coal is an inexpensive fuel. However, its high ash content, high moisture content and low calorific value cause flammability and ash cohesion problems. With regard to flammability, the main technology for efficient combustion depends on how to accelerate ignition and form a stable flame. Cohesion of ash to the design of the burner and the surface of the walls of the combustion chamber is caused by the low melting point of the ash. This is due to the fact that brown coal is rich in calcium, sodium and similar substances. In addition, the cohesion of the ash is accelerated by the fact that brown coal must be supplied in large quantities to compensate for the low calorific value compared to coal, while generating in accordance with this a large amount of ash. Such slagging and external pollution is a disadvantage of brown coal. Accordingly, in order to use low grade coal, for example brown coal and lignite, to burn fuel in a burner, it is necessary to achieve efficient fuel combustion and reduce ash cohesion.

The methods of burning brown coal, which are generally used abroad, are the method of tangential combustion of fuel and the method of angular combustion of fuel. In the first method, a burner chamber is provided in each side wall of the combustion chamber, which consists of fuel channels and ventilation channels to provide combustion. In the latter method, the burner chamber consists of fuel channels and ventilation channels to provide combustion in each corner of the combustion chamber.

The difference between these methods and the so-called opposed fuel combustion method is described below, in which a group of burners is provided in each of the surfaces of the opposite walls of the combustion chamber, which is used, in general, in Japan for burning coal.

In the method of opposed combustion of fuel, each burner (many tubes for supplying fuel and combustion air) is regulated by the automatic flame stabilization method. In brown coal combustion methods, instead of the automatic flame stabilization method implemented at the outlet of the burner, the high-speed flow of combustion air has kinetic energy and mixes with fuel around the middle of the combustion chamber, thereby promoting stable combustion.

On Fig shows a front view (from the side of the combustion chamber) of an example of a chamber 37 of the burner corresponding to the method of angular combustion of fuel or the method of tangential combustion of fuel. Each air stream has a different speed depending on a different purpose. The central air supply pipe 124 mixes the air with the fuel supplied by the exhaust gas stream from the fuel atomizer 125, thereby increasing the oxygen concentration and the acceleration of combustion. The external air supply pipe 126 delivers a high-speed flow having high penetration, having a speed of 50 m / s or more, thereby stabilizing the combustion of fuel around the middle of the combustion chamber.

The main technology necessary to ensure dominance in the international market in the relatively new area of burning low-grade coal, for example brown coal, is a pulverized coal burner that can operate even when the load changes depending on the change in the demand for electric load. In Western Europe, boilers must be operated at partial load, in some cases reaching 30% of the nominal value. In such cases, the prior art has the following problems.

As described above, an important moment of burning (brown coal) corresponding to the prior art (the method of angular combustion of fuel and the method of tangential combustion of fuel) is the need to provide a high-penetrating high-speed flow of the mixture of fuel and combustion air in order to stabilize combustion in the combustion chamber. By reducing the load in the combustion chamber, the aforementioned kinetic energy of the high-speed flow from the burner chamber 37 is also reduced, thereby causing instability in the flame plume. On Fig shows a cross section of the combustion chamber 41 in accordance with the method of angular combustion of fuel, illustrating an example of a change in the configuration of the flame of the flame, if the load of the combustion chamber 41 is reduced from a high load to a low load. At high load, as shown in Fig. 31 (a), the high-speed flow from the burner chamber 37 forms an outlet section 38 near the exit of the burner and additionally forms a stable combustion region located between the vicinity of the exit and the middle of the combustion chamber 41, thereby ensuring efficient combustion .

In contrast, at low load, the flow rate and, therefore, the kinetic energy of each high-speed flow from the burner chamber 37 decreases. Accordingly, the region of stable combustion, as shown in Fig. 31 (a), is not formed and, therefore, the combustion is unstable (the entire region of the combustion chamber 41 becomes dark, as shown in Fig. 31 (b)). To prevent extinguishing the burner flame at low load, near the air channel 49 formed in the upper part of the combustion chamber 41, as shown in the section shown in Fig. 32, a flame-temperature detector 48 is provided for monitoring the formation of the stable combustion region of the combustion chamber 41. This flame-temperature detector 48 detects that the quenching of the flame took place when the brightness of the combustion chamber 41 decreases, as shown in Fig. 31 (b).

If this is the case, since the formation of a stable combustion region in the combustion chamber 41 is influenced by the kinetic energy of the high-speed flow of each burner, the method according to the prior art is not applicable at low load. In this case, as shown in FIGS. 31 (a) and FIG. 31 (b), burner chambers 37 are provided at the bottom of the combustion chamber, whereby high-speed flows of the mixture of fuel and transporting gas from the burner chambers 37 are mixed with combustion air, supplied from the air channels 49, forming in accordance with this flame.

In addition, when the device for burning fuel (furnace chamber) corresponding to the prior art is operated at a high load, that is, when a large amount of fuel is supplied to the burners, heat radiation heats the burner structure to a higher temperature. Since low-grade coal ash, such as brown coal or lignite, has a lower melting point, the ash lying on the heated section of the burner structure melts, and the amount of molten ash gradually increases. The growth of molten ash can interfere with fuel combustion. Accordingly, under high load conditions it is necessary to form a flame in a position that is far from the burner.

An object of the present invention is to provide a burner. operating on solid fuel and the method of combustion using a burner operating on solid fuel, which can provide stable combustion in a wide range of loads of the combustion chamber from operating conditions at high load to operating conditions at low load, and, therefore, are suitable for burning low-grade fuel , for example brown coal and lignite; a device for burning fuel in which the specified burner is used, and a method for operating it and a coal-fired boiler using the specified burner.

Another objective of the present invention is the provision of a burner suitable for opposed combustion of fuel and capable of efficiently burning pulverized coal, for example brown coal having poor ash properties, near the exit of the burner and thereby preventing ash cohesion in the vicinity of the burner; and devices for burning fuel that use the specified burner.

An additional objective of the present invention is the provision of a burner suitable for angular combustion of fuel and tangential combustion of fuel and capable of forming a stable combustion region around the middle of the combustion chamber even at a low burning load of the combustion chamber by preventing ash from cohesion on the side walls of the racing chamber into fuel burning devices, which use the specified burner

Another objective of the present invention is the provision of a multi-tube burner suitable for opposed combustion of fuel, angular combustion of fuel and tangential combustion of fuel and a device for burning fuel, which use the specified burner.

The above tasks are solved due to the fact that they are offered

a solid fuel burner comprising a central air supply tube for ejecting air;

a fuel atomizer provided outside of said central air supply tube and ejecting a fluid mixture consisting of solid fuel and a carrier gas;

additional vents or tubes for supplying additional air provided in the inner surface of the wall of the fuel atomizer and ejecting air; and

one or more external air supply tubes provided outside said fuel atomizer and ejecting combustion air, wherein the outlet of any one or said central air supply tube and said additional ventilation holes or additional air supply tubes is located in a position located upstream of the burner processing chain from the outlet of said fuel atomizer, and heated and / or compressed air are connected to the indicated additional ventilation openings or supply pipes to olnitelnogo air.

Further, in the burner, starting from the side upstream of the burner processing chain, an obstruction is provided on the outer surface of the wall of said central air supply tube, comprising a conical section having a gradually increasing cross section, and a conical section having a gradually decreasing cross section, and on the inside a wall narrowing element is provided on the wall of said fuel atomizer for temporarily narrowing the cross section of the channel of said fuel atomizer willow starting from the side upstream of the burner process chain and to expand the specified cross-section to the initial value, while a swirl is provided in the specified central air supply pipe and a swirl is provided in the specified external air supply pipe, while the outlet from the specified pipe an external air supply is provided with a guide designed to limit the ejection of external air and an expansion element is provided at the outlet of the specified external air supply pipe a flange designed to increase the rate of swirling of the external air flow from the specified external air supply pipe to eject at a deflection angle of 45 degrees or less relative to the central axis of the burner, while a ring flame stabilizer is provided between the specified fuel atomizer and the specified external air supply pipe designed to withstand the ejected flow of a mixture of solid fuel and air.

Further, an annular flame stabilizer is provided in the burner, having L-shaped protrusions directed inwardly towards the exit of the specified fuel atomizer, and the cross section of the channel down the process chain from the specified central air supply pipe is smaller than the cross section of the channel up the technological chain from the specified central supply pipe air, and the location of the specified swirl in the specified Central air supply tube is movable in the direction of the Central axis of the burner to the specified center Flax air supply tube and said central tube supplying air swirler provided for adjusting the intensity of swirling of the air flow depending on the combustion load.

The following provides a method of burning fuel using a solid fuel burner, in which the air ejection from the burner is supplied depending on the combustion load, as selected from the group comprising the air ejection mode, in which the air flow from the specified central air supply tube is ejected as rectilinear high speed flow or low swirl high speed flow; and an air ejection mode in which the air flow from said central air supply tube is ejected as a highly swirling high-speed flow and in which, at a low burning load, a high swirling high-speed flow is ejected from said central air supply tube, while at a high combustion load from said central tube a straight high-speed flow or a slightly twisted high-speed flow ejected into the air supply and in which combustion is carried out by adjusting the amount of air so that the ratio of the total amount of air supplied by the specified fuel atomizer, the specified Central air supply pipe and the specified additional ventilation holes or additional air supply pipes, to the amount of air required for complete combustion of the volatile substances of the fuel is maintained equal to 0.85-0 , 95, using a solid fuel burner in which the ratio of the amount of air ejected from the specified central air supply pipe to the amount of air ejected from these additional ventilation openings or additional air supply pipes is controlled depending on the combustion load and in which, at a low combustion load, the amount of air ejected from the specified central air supply pipe is reduced, and at the same time, the contribution of the amount of air is increased, ejected from these additional ventilation holes or tubes for supplying additional air; while at a high combustion load, the amount of air ejected from said central air supply tube is increased, and at the same time, the contribution of the amount of air ejected from said additional air vents or additional air supply tubes is reduced.

An apparatus for burning fuel using an exhaust gas as a transport gas for solid fuel used in a solid fuel burner and comprising a combustion chamber having a wall surface of the combustion chamber equipped with a plurality of said solid fuel burners, in which many of these burners are located in the corners or in opposite surfaces of the side walls of the combustion chamber so as to form a pair or pairs of modules, and in which the Central tube the burner air supply for solid fuel burners has a cylindrical shape and in which a pair of air supply pipes for supplying air is connected to a part upstream of the central air supply pipe, and wherein said pair of said air supply pipes are connected so so that air is introduced in a tangential direction in each of the opposing positions of the cross-sectional circle of said central air supply tube.

The following provides a method for controlling a device for burning fuel, in which, at a high combustion load, said fuel burning device increases the amount of air ejected from said central air supply pipe, and at the same time reduces the contribution of the amount of air ejected from said additional ventilation openings or additional air supply pipes, due to which, starting from a position far from the specified solid fuel burner, a torch n a solid fuel fuel, in which, at a low burning load, said fuel burning device reduces the amount of air ejected from said central air supply pipe, and at the same time increases the contribution of the amount of air ejected from said additional ventilation openings or additional air supply pipes, due to which, directly below the process chain from the outlet of the fuel atomizer of the specified solid fuel burner, a torch of flame fuel and in which in the specified burner that runs on solid fuel, or on the surface of the wall of the combustion chamber near the specified burner that runs on solid fuel, thermometers or flame-temperature detectors are provided, thereby controlling the amount and intensity of the swirl of air ejected from the specified central air supply tubes of said solid fuel burner, or in an alternative embodiment, the amount of air ejected from said additional veins openings or additional air supply tubes in response to a signal from these measuring devices, and in which, at high load of said fuel burning device, combustion is carried out in a position that is 0.5 m or more away from the fuel atomizer exit on the central axis of the fuel atomizer in the combustion chamber; in which, at a low load of the specified device for burning fuel, starting from a position located near the surface of the wall of the combustion chamber outside the outlet of the fuel atomizer, a solid fuel flame is formed in the combustion chamber and in which at high load of the said device for burning fuel, using flame-temperature detectors or by visual inspection carry out the current control of the torch in the middle of the combustion chamber, where the torches of the solid fuel flame of the burners working and solid fuels; whereas at a low load of the specified device for burning fuel, the torch formed near the exit of each burner operating on solid fuel is monitored and in which at a high load of the said device for burning fuel, an identical amount of air is supplied into the two air supply pipes, as in the specified Central air supply tube; whereas at a low load of said fuel burning device, a different amount of air is supplied to the two air supply tubes than to said central air supply tube; whereby depending on the high or low load, the intensity of swirling of the central air flow is controlled.

Further, a coal-fired boiler is provided, comprising a combustion chamber having a wall surface equipped with a plurality of solid fuel burners, a superheater provided in said combustion chamber for boiling water to generate water vapor by using a flame produced by burning solid fuel in said combustion chamber, wherein a coal-fired boiler system is proposed comprising a coal-fired boiler, a chimney serving as a channel for exhausting of gas from said boiler; a device for cleaning the exhaust gas provided in the specified chimney; a device for transporting pulverized coal, designed to transport coal in the form of pulverized coal to the burners in the specified boiler; a device for controlling the supply of pulverized coal, designed to adjust the amount of pulverized coal supplied from the specified device for transporting pulverized coal to these burners; and a device for adjusting the air supply, designed to adjust the amount of air ejected from these burners.

A coal-fired power plant, comprising a combustion chamber having wall surfaces of the combustion chamber, equipped with a plurality of solid fuel burners, a boiler for boiling water to produce water vapor by using the heat of combustion obtained by burning solid fuel through said burners; a steam turbine driven into rotation by the steam generated by said boiler; and an electric generator driven by said steam turbine.

The following is a solid fuel burner comprising a fuel atomizer for ejecting a fluid mixture consisting of solid fuel and a transport gas; additional air vents or additional air supply tubes provided on an inner wall surface of said fuel atomizer and ejecting air in which heated and / or compressed air is connected to said additional air vents or additional air supply tubes, and in which outlets of said additional air vents or additional air supply pipes are located on the side up the burner process chain from the outputs of the specified a fuel atomizer, while inside the fuel atomizer there is an obstacle comprising a section having a gradually increasing cross section and a section having a gradually decreasing cross section in the direction from the side upward along the burner processing chain, to the downward side along the burner technological chain, and on the inner surface a wall narrowing element is provided for the wall of said fuel sprayer for temporarily narrowing the cross section of the channel of said fuel sprayer in the direction from the side up the burner process chain to the side down the burner process chain and to expand the specified cross section to the original value, while in the burner that is powered by solid fuel in the external air supply pipe a swirl is provided, and at the outlet of the external air supply pipe a guide rail is provided for restricting the direction of the flow of external air ejected from the external air supply pipe and between said fuel atomizer and the pipe An external air supply is provided with a ring flame stabilizer designed to withstand the ejected flow of a mixture of solid fuel and air and a ring flame stabilizer is provided, which has L-shaped protrusions directed inward to the end of the wall surface of the specified fuel atomizer, while the exhaust gas is used as a solid transporting gas gas fuel and in which the outlet from said additional ventilation holes or additional air supply tubes is located between nical section of the obstacle; having a gradually decreasing cross section, and an annular flame stabilizer, and the air supply section for said additional ventilation holes or additional air supply pipes is connected to air boxes for supplying compressed air to an external air supply pipe, wherein the air supply section for said additional ventilation holes or additional air supply pipes connected to a device for supplying combustion gas, specially designed for supplying air for For combustion to said air supply section, and said combustion air supply device is connected to means for supplying oxygen-rich gas or pure oxygen, and a device for adjusting the combustion gas flow rate is provided in said combustion air supply device.

The following provides a method of burning fuel using a solid fuel burner in which, with a low burning load, the amount of air supplied from said additional ventilation holes or additional air supply pipes is increased, while at a high burning load, the amount of air supplied from said additional vents or tubes for supplying additional air, and with a low burning load, reduce the amount of air supplied from the pipe ki supplying outside air, which of said feed tubes outside air is closest to said fuel spray, or alternatively increase the intensity of its twist; and with a high burning load, the amount of air supplied from the external air supply pipe, which of these external air supply pipes is closest to the specified fuel atomizer, is increased, or alternatively, the intensity of its swirling is reduced.

Further, there is provided a device for burning fuel containing a combustion chamber having a wall surface equipped with a plurality of solid fuel burners, as well as a device for burning fuel containing a combustion chamber having a wall surface equipped with a plurality of solid fuel burners, and a superheater provided in said combustion chamber for boiling water in order to generate water vapor by using a flame torch obtained by using heat burned out I obtained through the combustion of solid fuel in said combustion chamber.

A coal-fired boiler is also provided, comprising a combustion chamber having a wall surface equipped with a plurality of solid fuel burners, and a superheater provided in said combustion chamber for boiling water to generate water vapor by using a flame produced by using heat combustion obtained by burning solid fuel in said combustion chamber.

Finally, a method for controlling a device for burning fuel is proposed, in which, at a high burning load in said fuel burning device, a solid fuel flame is formed starting from a position far from said solid fuel burner; in which, at a low burning load, in said fuel burning device, a fuel flame is formed starting from a position of the combustion chamber close to the surface of the wall of the combustion chamber immediately below the process chain from the outlet of the fuel atomizer of said solid fuel burner, and in which solid fuel burners, or on the wall surface of the combustion chamber close to said solid fuel burners, provide thermometers or flame-temperature e detectors, due to which, in these solid fuel burners, the amount of air ejected from the indicated additional ventilation openings or additional air supply pipes is controlled in response to a signal from these measuring devices and in which, at high load, the specified device for burning fuel carried out in a position spaced from the exit of the fuel atomizer by 0.5 m or more on the central axis of the atomizer in the combustion chamber; in which at low load the specified device for burning fuel, starting from a position located near the surfaces of the walls of the combustion chamber outside the outlet of the fuel atomizer in the combustion chamber, a solid fuel flame is ignited, in which at high load of the specified device for burning fuel by using flame-temperature detectors or with the help of visual inspection carry out the current control of the torch in the middle of the combustion chamber, where the torches of the solid fuel flame of the burners operating on solid fuel; while at a low load of the specified device for burning fuel, a separate flame formed near the exit of each burner operating on solid fuel is monitored and in which, at a low load of the said device for burning fuel, the amount of air is controlled so that the ratio of the total amount of air supplied the specified burner operating on solid fuel, to the amount of air required for the complete combustion of volatile substances in the fuel, was maintained at the level of 0.85-0.95.

Finally, a coal-fired power plant is proposed, comprising a combustion chamber having wall surfaces of the combustion chamber, equipped with a plurality of solid fuel burners, a boiler for boiling water to generate water vapor by using the heat of combustion obtained by burning solid fuel through said burners; a steam turbine driven by means of water vapor generated by said boiler; and an electric generator driven by said steam turbine.

The burner that provides a low concentration of NO _x corresponding to the prior art has a configuration suitable for reducing the concentration of NO _x in the exhaust gas of conventional coal. However, in a fuel burning device using flammable fuels such as brown coal and peat, the carrier gas used is not primary air, but off-gas with a low oxygen concentration to prevent spontaneous ignition. In this case, ignition near the burner is difficult and causes the following two problems.

(1) Due to the difficulty of controlling the torch near the burner, operation without auxiliary oil or fuel gas for combustion is limited by a high load condition in which the combustion temperature is high enough.

(2) No reduction in NO _x concentration is obtained because the combustion rate is low near the active combustion zone, where the fuel is in excess with respect to the combustion air, that is, since the combustion rate is high after mixing with secondary and tertiary air.

The above problems result from the use of gas with a low oxygen concentration as a coal transporting agent. To solve this problem, it is possible to supply combustion air to the fuel atomizer near the exit of the burner in order to increase the oxygen concentration. However, this configuration reduces the concentration of pulverized coal and, therefore, does not improve the ignition of the fuel.

Thus, it is an object of the present invention to provide a solid fuel burner capable of quickly and efficiently burning pulverized coal, for example brown coal having poor ash properties, near the exit of the burner and thereby providing combustion with a reduced concentration of No _x ; and devices for burning fuel that use the specified burner.

DESCRIPTION OF THE INVENTION

The burner of the present invention is suitable for using a fluid mixture comprising solid fuel consisting of low-grade coal, for example brown coal and lignite; and a carrier gas having an oxygen concentration of less than 21%.

(1) A first embodiment of a burner according to the present invention is a solid fuel burner comprising a central air supply tube for ejecting air; a fuel atomizer provided outside the central air supply tube and an ejected fluid mixture consisting of solid fuel and a transport gas; additional vents or tubes for supplying additional air provided in the inner surface of the wall of the fuel atomizer and ejecting air; and one or more external air supply tubes provided outside the fuel atomizer and ejecting combustion air.

In the aforementioned burner, it is possible to increase the amount of air ejected from additional ventilation holes or additional air supply tubes for ejecting air along the inner side of the wall of the fuel atomizer. Air ejected from additional ventilation openings or additional air supply tubes increases the oxygen concentration near the inner wall of the fuel atomizer. This speeds up combustion compared with a lower oxygen concentration. The ignition of the fuel, respectively, is accelerated and, therefore, a flame is formed, starting from the vicinity of the fuel atomizer.

In the aforementioned burner, further comprising a swirl in the central air supply tube, an air ejection from the central air supply tube may be selected in response to a combustion load in the form of (1) a direct high-speed flow or a slightly twisted high-speed flow; and (2) a highly swirling high speed flow.

In this case (a) the output of the central air supply pipe and / or (b) the output of the additional ventilation holes or additional air supply pipes are preferably located upstream from the outlet of the fuel atomizer inside the burner. In accordance with this configuration, a mixture of fuel with air ejected from (a) the central air supply pipe and / or (b) additional ventilation holes or additional air supply pipes is obtained in a fuel atomizer. This allows you to partially increase the oxygen concentration of the gas transporting fuel.

The distance between the outlet of the fuel atomizer and the outlet of the central air supply tube and the distance between the outlet of the fuel atomizer and the outlet of the additional ventilation holes or the air supply tubes are preferably set such that the residence time of the fuel in the atomizer does not exceed the ignition delay time (approximately 0.1 sec) fuel. The aim of this is to prevent the formation of a reverse flame and damage from burning caused by the formation of a flame in the fuel atomizer. Since the gas transporting the fuel, as a rule, passes through the fuel atomizer at a speed of 10-20 m / s, the above distances are 1-2 m or less.

If the element of the narrowing of the channel, intended for the gradual temporary narrowing of the cross section of the fuel atomizer, starting up the burner process chain, and to restore the cross section, is provided on the inner side of the wall of the atomizer of the fuel of the burner, then the flow of fuel particles (pulverized coal) having higher inertia than the inertia of the fuel-transporting gas (exhaust gas or similar gas) is focused in the region of the central axis. In addition, if an obstacle consisting of a conical section having a gradually increasing cross section starting upstream of the burner process chain and a subsequent conical section having a gradually decreasing cross section is provided on the outer surface of the wall of the central air supply tube so as to be lower the technological chain from the channel narrowing element, the flow of fuel particles (pulverized coal), focused in the region of the central axis, expands with an obstacle and It passes through the fuel atomizer channel after passing through the obstacle. In this case, a stream of fuel particles (pulverized coal) having a higher inertia than the inertia of the gas transporting the fuel (exhaust gas) is concentrated in the region of the inner side of the wall of the fuel atomizer and passes towards the exit. This concentrated stream of pulverized coal in the area of the inner wall of the fuel atomizer simply enters into contact interaction with external air (combustion air) near the outlet of the fuel atomizer, and in additional contact interaction with high-temperature gas recirculation zones formed lower down the process chain from the ring flame stabilizer, described later, simply igniting it.

If the specified burner corresponding to the present invention operates at high load, the fuel ejected from the fuel atomizer is heated by strong heat radiation from the combustion chamber. This situation provides the possibility of stable combustion, even if the fuel is ejected from the fuel atomizer at high speed. In this case, the air is ejected in the form of a rectilinear high-speed flow or a weakly twisted high-speed flow (with a swirl coefficient of 0.3 or less) from the central air supply tube, whereby the flame leaves the vicinity of the burner so that the flame forms in position far from the burner. This prevents high-temperature heating of the burner structure by means of heat emission from the torch.

In contrast, if the burner according to the present invention operates at a low load, then the air is ejected as a highly swirling high-speed flow (with a swirl coefficient of 0.5 or more) from the central air supply tube, thereby accelerating the mixing of the high-speed fuel flow with air. In addition, since the rate of fuel ejection on the central axis of the burner is reduced by the swirling high-speed air flow from the central air supply tube, the residence time of the fuel near the fuel atomizer becomes longer. Accordingly, the fuel is heated near the fuel atomizer at a temperature necessary for combustion, so that a torch is formed starting from the vicinity of the atomizer.

In the above burner of the present invention, the ratio of the amount of air ejected from the central air supply pipe to the amount of air ejected from the additional ventilation holes or additional air supply pipes can be adjusted depending on the burning load. For example, with a low burning load, the amount of air ejected from the central air supply tube is reduced, while the amount of air ejected from the additional ventilation holes or additional air supply tubes is increased. In contrast, with a high combustion load, the amount of air ejected from the central air supply pipe is increased, while the amount of air ejected from the additional ventilation holes or additional air supply pipes is reduced.

In the above burner of the present invention, the amount of air is controlled during the combustion process, preferably so that the air ratio for volatile substances (the ratio of the total amount of air supplied from the fuel atomizer, central air supply pipe and additional ventilation openings or additional air supply pipes to the amount of air required for complete combustion of volatile substances contained in the fuel) was 0.85-0.95.

In addition, at the end of the partition between the fuel atomizer and the external air supply pipe, it is preferable to counteract (annular flame stabilizer) the gas flow from the fuel atomizer and the air flow from the external air supply pipe.

The pressure down the process chain from the annular flame stabilizer decreases, due to which recirculation zones are formed, directed from the direction down the process chain to the direction up the process chain. In the recirculation zones, in addition to fuel and air ejected from the external air supply pipes, there is a high-temperature exhaust gas formed lower in the process chain. Accordingly, the recirculation zones have a high temperature, serving accordingly as a source of ignition for the high-speed flow of fuel passing in the vicinity. This provides the possibility of stable formation of a flame, starting from the exit of the fuel atomizer.

In addition, an annular flame stabilizer having an L-shaped protrusions may be provided on the inner surface of the outlet wall of the fuel atomizer. Such an annular flame stabilizer similarly accelerates the ignition of the fuel.

In the above burner according to the present invention, the cross section of the channel downstream of the central air supply pipe may be smaller than the cross section of the channel upstream of the central air supply pipe and then the position of the swirl provided in the central air supply pipe may be shifted in the direction the central axis of the burner in the central air supply tube. In accordance with this configuration, adjusting the position of the swirl allows controlling the intensity of the swirl of the air flow depending on the burning load.

At low load, the swirl is displaced lower along the channel chain to a position where the cross section in the central air supply tube is smaller, due to which the high-speed air flow from the central air supply tube is strongly twisted, forming a flame near the burner in accordance with this. In contrast, at high load, the swirl is displaced higher along the channel’s processing chain to a position where the cross section in the central air supply tube is larger, due to which the high-speed air flow from the central air supply tube is slightly twisted, forming in accordance with this a flame plume far from burners in the combustion chamber.

If the temperature of the surface of the burner or the wall of the combustion chamber rises too high, the burnt ash cohere on the burner structure and the wall of the combustion chamber and cohesion gradually increases. This phenomenon, called slagging, tends to occur. To suppress slagging, in response to a signal from a thermometer or radiation intensity meter provided on the surface of the burner or wall of the combustion chamber, the amount or intensity of swirling of air ejected from the central air supply tube can be adjusted, or alternatively, the amount of air can be adjusted ejected from additional ventilation openings or additional air supply tubes. Adjusting the amount or intensity of air swirling causes a change in the position of the formation of the flame in the combustion chamber, allowing in accordance with this adjustment of the intensity of heat radiation to the surface of the burner and the wall of the combustion chamber.

At high load, due to the high thermal load of the combustion chamber, the flame is preferably formed in a position far from the burner. At low load, due to the low thermal load of the combustion chamber, the temperature of the surface of the burner and the wall of the combustion chamber does not rise as high as in the case of high load, even if the flame is formed near the burner.

If the aforementioned burner according to the present invention is used in such a device for burning fuel, then the central air supply tube has a cylindrical shape. A pair of air ducts for supplying air is connected to a part upstream in the processing chain of the central air supply tube. Each duct is connected so as to supply air from a tangential direction in a mutually opposite position of a circular cross section of a central air supply tube. If the device for burning fuel operates at a high combustion load (for example, 60-70% or higher), then each air duct brings the same amount of air into the central air supply pipe. In contrast, if the device for burning fuel operates at a low burning load (for example, 60-70% or lower), then each air duct supplies a different amount of air into the central air supply pipe. Due to such work, the rate of swirling of the central high-speed air flow is regulated depending on the load.

(2) A second embodiment of a burner in accordance with the present invention is a solid fuel burner, comprising: a fuel atomizer for ejecting a fluid mixture consisting of solid fuel and a transport gas; additional vents or tubes for supplying additional air provided in the surface of the wall of the fuel atomizer and ejecting air; and one or more external air supply tubes provided outside the surface of the wall of the fuel atomizer and ejecting air. In contrast to the burner according to the first embodiment of the present invention, the burner according to the second embodiment of the present invention does not comprise a central air supply tube for ejecting air.

In a second embodiment of the burner of the present invention, it is possible to increase the amount of air ejected from additional ventilation openings or additional air supply tubes for ejecting air along the inner surface of the wall of the fuel atomizer. Air ejected from additional ventilation openings or additional air supply tubes increases the oxygen concentration near the inner surface of the fuel atomizer wall. This accelerates the fuel combustion reaction compared to the case of low oxygen concentration. The ignition of the fuel, respectively, is accelerated and, therefore, a torch is formed, starting from the vicinity of the fuel atomizer.

In the second embodiment of the burner, the outlet (end) of the additional ventilation holes or additional air supply tubes is preferably located upstream of the outlet (end) of the fuel atomizer in the burner. In accordance with this configuration, a mixture of fuel with air ejected from additional ventilation openings or additional air supply tubes is obtained in a fuel atomizer. This allows you to partially increase the oxygen concentration of the gas transporting fuel. The distance between the outlet of the fuel atomizer and the outlet of the additional air vents or additional air supply tubes is preferably set so that the residence time of the fuel in the atomizer does not exceed the ignition delay time (approximately 0.1 sec) of the fuel. The aim of this is to prevent the formation of a reverse flame and damage from burning caused by the formation of a flame in the fuel atomizer. Since the gas transporting the fuel typically passes through the fuel atomizer at a speed of 10-20 m / s, the above distance is 1-2 m or less.

A channel constriction element for temporarily narrowing the cross section of the fuel atomizer, gradually starting up the burner process chain and extending down the process chain, and for restoring the cross section, is preferably provided on the inner side of the wall of the burner fuel atomizer. This narrowing of the cross section increases the speed of the gas transporting fuel passing through the fuel atomizer from the fuel atomizer. Accordingly, even if a torch is formed in the fuel atomizer due to a temporary deceleration of the fuel flow, the reverse flame is prevented from passing up the channel narrowing section formed by the channel narrowing element along the process chain. In addition, if the obstacle consists of a section having a gradually increasing cross section starting upstream of the burner process chain and passing down the process chain, and a subsequent section having a gradually decreasing cross section, is provided inside the fuel atomizer so as to be located lower in the process chain from the element of the narrowing of the channel, the flow of fuel particles (pulverized coal), focused in the region of the central axis, is expanded by an obstacle and then passes Through the channel of the fuel atomizer. In this case, the flow of fuel particles (pulverized coal), having a higher inertia than the inertia of the gas transporting the fuel, is concentrated in the region of the inner side of the wall of the fuel atomizer and passes towards the exit. This concentrated stream of pulverized coal in the area of the inner side of the wall of the fuel atomizer simply enters into contact with external air ejected from the external air supply pipe in the vicinity of the outlet of the fuel atomizer. The pulverized coal stream enters into additional contact interaction with the high-temperature gas of the recirculation zones formed lower down the process chain from the ring flame stabilizer described later, simply igniting it.

In addition, an annular flame stabilizer opposed to the flow of the solid fuel mixture from the fuel atomizer and the air flow is preferably provided at the end of the wall surface between the fuel atomizer and the external air supply pipe.

The pressure in the combustion chamber lower in the process chain from the annular flame stabilizer decreases, due to which recirculation zones of the current mixture are formed, having a direction from a position lower in the process chain to a position higher in the process chain. In the recirculation zones, in addition to air, fuel and gas transporting fuel, ejected from the fuel atomizer and from the external air supply pipe, there is a high-temperature exhaust gas generated in the combustion chamber downstream of the burner. Accordingly, the recirculation zones have a high temperature, serving accordingly as an ignition source for a high speed fuel flow. This allows stable flame formation starting from the exit of the fuel atomizer.

An annular flame stabilizer having an L-shaped protrusion may be provided on the inner surface of the outlet wall of the fuel atomizer. Such an annular flame stabilizer similarly accelerates the ignition of the fuel.

If exhaust gas is used as a gas transporting solid fuel, then between the conical section having a decreasing cross section in the obstacle and the annular flame stabilizer, additional vents or additional air supply tubes are provided. This configuration allows the gas mixture to have the amount of oxygen needed for combustion. This gas mixture collides with an annular flame stabilizer, thereby allowing efficient ignition by an annular flame stabilizer. In addition, even at a low burning load and even if pulverized coal is burned in the combustion chamber, for example, brown coal having poor ash properties, fast and efficient combustion is obtained near the burner outlet, thereby obtaining a low NO _x concentration and preventing cohesion the surface of the wall of the combustion chamber near the burner.

In the above burner in accordance with the present invention, the amount of air ejected from the additional ventilation openings or additional air supply pipes can be adjusted depending on the burning load in the fuel combustion device (combustion chamber).

Typically, in solid fuel burners not limited to the above solid fuel burners of the present invention, at a high burning load in the fuel combustion device (combustion chamber), a solid fuel torch is preferably formed in the combustion chamber far from the burner working on solid fuel. In contrast, at a low burning load in the fuel combustion device (combustion chamber), a solid fuel flame is preferably formed in the combustion chamber starting from a neighborhood of the surface of the wall of the combustion chamber immediately downstream of the outlet of the solid fuel atomizer.

For example, if a solid fuel burner has additional ventilation openings or additional air supply pipes, then with a low burning load in the fuel combustion device (combustion chamber), the amount of air ejected from additional ventilation openings or additional air supply pipes can be increased . Air ejected from additional ventilation openings or additional air supply tubes increases the oxygen concentration near the inner surface of the fuel atomizer wall. This accelerates the fuel combustion reaction compared to the case of low oxygen concentration. Consequently, the ignition of the fuel is accelerated and, therefore, a flame is formed starting from the vicinity of the outlet (end) of the fuel atomizer. With a high burning load in the device for burning fuel (combustion chamber), the amount of air ejected from additional ventilation openings or additional air supply pipes is reduced. This operation reduces the oxygen concentration near the inner side of the wall of the fuel atomizer, thereby slowing down the fuel combustion reaction in comparison with the case of a low oxygen concentration. Consequently, ignition of the fuel slows down and, therefore, a torch forms in the combustion chamber in a position far from the burner.

With a high combustion load in the device for burning fuel (combustion chamber), the temperature of the solid fuel burner and the wall surface of the combustion chamber increase. Burnt ash, respectively, cohere on the burner structure and cohesion gradually grows. This phenomenon, called slagging, tends to occur. To suppress slagging on the surface of the burner structure and the wall of the combustion chamber, with a high load of combustion in the device for burning fuel (furnace chamber), the flame is shifted to a position far from the burner, thereby comparatively reducing the temperature of the surface of the burner and the wall of the combustion chamber. At a low combustion temperature, the amount of air is adjusted approximately so that the air coefficient for volatile substances (the ratio of the total amount of air supplied from the fuel atomizer and additional ventilation openings or additional air supply pipes (if provided) to the amount of air required for complete combustion of the volatile substances contained in the fuel) was 0.85-0.95. With a low load, stable combustion is generally difficult to achieve. However, the air coefficient for volatiles, of 0.85-0.95, increases the temperature of the flame, providing in accordance with this continued stable combustion.

In addition, in order to suppress slagging on the surface of the burner structure and the combustion chamber wall, in response to a signal from a thermometer or flame temperature detector provided in the burner or the peripheral surface of the combustion chamber wall, the amount of air ejected from additional ventilation openings or tubes can be adjusted supply of additional air. Adjusting the amount of air causes a change in the position of the formation of the torch in the combustion chamber, providing in accordance with this the ability to adjust the intensity of heat radiation to the surface of the burner and the wall of the combustion chamber.

As described above, at a high load of the fuel combustion device due to the high heat load of the combustion chamber, a flame torch is preferably formed in the combustion chamber at a position far from the burner. In contrast, with a low load of the fuel combustion device due to the low heat load of the combustion chamber, the temperature of the burner and the surface of the peripheral wall of the combustion chamber does not rise so high compared to the case of high load. A flame torch, respectively, can be formed in the combustion chamber near the burner.

In the combustion method using the first and second embodiments of the burner according to the present invention, with a high load of the fuel combustion device, the fuel is ignited in a position far from the burner, and therefore, a torch is formed in the middle of the combustion chamber. For monitoring the flame generated by the burners at high load, the torch is preferably controlled in the middle of the combustion chamber, where the flame from the burners is drained. In contrast, when the fuel burner is low loaded, the fuel is ignited near the burner and a flame is formed near each burner. In addition, in some cases, each burner in the combustion chamber form an independent torch. Accordingly, the torch formed at the outlet of each burner is preferably controlled at low load.

In the first and second embodiments of the burner of the present invention, additional ventilation openings may be used in place of the additional air supply pipes. Additional vents provided in the wall surface of the fuel atomizer are in the form of a circle, ellipse, rectangle and square. Four, eight or twenty maximum additional ventilation openings may be provided, spaced at the same distance in the radial direction of the fuel atomizer. One additional ventilation hole formed by separating the fuel atomizer in the radial direction, unfortunately, leads to the formation of an uneven flow of additional air ejected from the slots in the fuel atomizer.

Preferably, heated air is supplied to the additional ventilation openings or additional air supply pipes. The heat source for this purpose may be compressed air supplied to the grinder fan to form pulverized coal, or in an alternative embodiment, air supplied to the air box, heated for combustion in the burner. Compressed air supplied to the grinder fan is more preferred due to its higher pressure.

The air supply section for additional ventilation openings or additional air supply pipes may be connected to an air box for supplying combustion air (external air, for example, secondary or tertiary air) to the external air supply pipe. However, it is more preferable that the air supply section is connected to a specially designed device for supplying combustion air.

If the air supply section for additional ventilation openings or additional air supply pipes is connected to a specially designed device for supplying combustion air, then oxygen-enriched air having a high oxygen concentration or pure oxygen can simply be supplied regardless of the flammability of the solid fuel, for example, pulverized coal, and in response to reducing the load of the device for burning fuel. In addition, the device that controls the flow rate of combustion air for a specially designed device for supplying combustion air provides the ability to easily control the flow rate.

In addition, if the combustion gas (air) effective for igniting the fuel is supplied to the burner by means of a specially designed device for supplying combustion air, the pressure of this combustion gas (air) may differ from the pressure generated by the air box. This allows unlimited selection of the size of the combustion air supply aperture for the purpose of ignition. In addition, a device that controls the flow rate of combustion air provides the ability to easily control the feed rate.

At the outlet of the external air supply pipe of the aforementioned first and second embodiments of the burners of the present invention, a guide is provided for restricting the direction of ejection of the external air, due to which the flow of external air (hereinafter referred to as secondary and tertiary air below) is provided with some divergence in order to form a diverging flame torch. In this case, the slope of the guide is set to 45 degrees or less relative to the central axis of the burner, which ensures such kinetic energy of the high-speed combustion air stream ejected from the external air supply pipe to contain a fluid mixture of exhaust gas and pulverized coal. The torch is narrowed by a high-speed air stream having a higher kinetic energy, due to which a stable torch (combustion area) is formed in the combustion chamber, providing, accordingly, the possibility of efficient combustion of pulverized coal.

If a guide designed to direct the external high-speed air flow from the external air supply tube is provided at such an angle that the external high-speed air flow moves along the burner and the outer wall surface of the combustion chamber, the external high-speed air flow cools the burner and the wall surface of the combustion chamber, preventing according to this slagging.

Fuel combustion devices equipped with a plurality of the above burners according to the first and second embodiments of the present invention in the surface of the combustion chamber include a coal-fired boiler, a peat-fired boiler, and a biomass (wood-fired) boiler, a heating oven and blast heater.

Thermometers or flame-temperature detectors are provided in the aforementioned first and second embodiments of the burner of the present invention, or in the wall of the combustion chamber outside the burner. In response to a signal from such a measuring device, the quantity and intensity of swirling air ejected from the central air supply tube of the burner are regulated, and / or the amount of air ejected from additional ventilation openings or additional air supply tubes is controlled. Due to this technological operation, depending on the load change, the position of the torch formation in the combustion chamber is accordingly regulated.

The following is an example of an appropriate measurement of the position of the formation of a torch. With a low burning load in the device for burning fuel, the end of the solid fuel flame in the combustion chamber is formed near the wall of the combustion chamber outside the outlet of the fuel atomizer. With a high burning load in the device for burning fuel, a flame is formed starting from a position 0.5 m or more away from the exit of the fuel atomizer on the central axis of the fuel atomizer.

At a high load of the fuel combustion device, a flame torch is monitored around the middle of the combustion chamber where the torches from the burners of the present invention merge by means of a flame temperature detector or by visual inspection. In contrast, at low load, the fuel combustion devices control the torch formed at the outlet of each burner of the present invention.

The present invention provides a coal-fired boiler system and a coal-fired power plant as described below.

(a) The coal-fired boiler system comprises a coal-fired boiler; a chimney that serves as a channel for the exhaust gas from the boiler; a device for cleaning the exhaust gas provided in the chimney; a pulverized coal transport device for conveying coal in the form of pulverized coal to a burner according to the present invention provided in a boiler; a device for regulating the supply of pulverized coal, designed to adjust the amount of pulverized coal supplied from the device for transporting pulverized fuel to the burner; and a device for adjusting the air supply, designed to adjust the amount of air ejected from the burner.

(b) A coal-fired power plant comprises a combustion chamber having a combustion chamber wall equipped with a plurality of burners according to the present invention; a boiler for boiling water in order to generate water vapor through the heat of combustion obtained by burning solid fuel through burners; a steam turbine driven into rotation by the steam generated by the boiler; and an electric generator driven by a steam turbine; wherein said coal-fired power plant uses coal-fired burners according to the present invention as said burners.

In the first and second embodiments of the burner in accordance with the present invention, a burner corresponding to an angular or tangential fuel combustion scheme, which is difficult to operate with a low load of the combustion chamber of the prior art, operates such that a stable burning area is formed around the middle of the combustion chamber at high load flame, and at low load it works according to the automatic flame stabilization scheme.

In this case, the solid fuel burners of the present invention form a module, and a plurality of modules are located at the corners or opposing side walls of the combustion chamber so as to form a pair or pairs of modules.

This method of burning fuel is applicable for a wide range of loads of the combustion chamber (specifically 30-100%), corresponding to the required change in power even in the combustion chamber for burning low-grade coal, such as brown coal and lignite.

It is characteristic that at high load in the lower part of the high-speed fuel flow from the burner an exhaust section is formed. At low load, an automatic flame stabilization scheme is used, that is, combustion is carried out starting from the bottom of the high-speed fuel flow from the burner. The release or ignition at the bottom of the high-speed fuel flow from the burner is controlled by adjusting the coefficient of distribution of combustion air (external air or farthest from the middle of the air) of the burner and / or by adjusting the rate of swirling of the combustion air through the use of a swirl provided in the tube (external air) burner.

When using the burner in accordance with the present invention in the combustion chamber of the boiler, the boiler can operate depending on the required power. This prevents excessive steam generation in the furnace chamber of the boiler to generate electricity, thereby ensuring efficient operation of the furnace chamber of the boiler and a significant reduction in operating costs for the furnace chamber.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of a pulverized coal burner according to a first embodiment of the present invention at a low load. FIG.

FIG. 2 is a cross-sectional view of a pulverized coal burner illustrated in FIG. 1 at high load.

FIG. 3 is a front view of a pulverized coal burner illustrated in FIG. 1 from the side of the combustion chamber.

FIG. 4 is a front view of a modification of a pulverized coal burner illustrated in FIG.

FIG. 5 is a sectional view of a modification of a pulverized coal burner illustrated in FIG.

FIG. 6 is a sectional view of a modification of a pulverized coal burner illustrated in FIG.

Fig. 7 is a cross-sectional view of a pulverized coal burner according to a second embodiment of the present invention at high load.

Fig. 8 is a cross-sectional view of a pulverized coal burner illustrated in Fig. 7 taken along line AA.

9 is a sectional view of a pulverized coal burner according to a third embodiment of the present invention.

FIG. 10 is a front view of a pulverized coal burner illustrated in FIG. 9 from the side of the combustion chamber.

11 is a sectional view of a pulverized coal burner according to a fourth embodiment of the present invention at low load.

Fig. 12 is a sectional view of a pulverized coal burner illustrated in Fig. 11 at high load.

FIG. 13 is a front view of a pulverized coal burner illustrated in FIG. 11 from the side of the combustion chamber.

Fig. 14 is a sectional view of a pulverized coal burner modification illustrated in Fig. 11 at high load.

Fig - front view of a modification of the burner, working on a pulverized coal, illustrated in Fig.11, from the side of the combustion chamber.

FIG. 16 is a sectional view of a modification of a pulverized coal burner illustrated in FIG. 11.

17 is a sectional view of a pulverized coal burner according to a fifth embodiment of the present invention at low load.

Fig. 18 is a cross-sectional view of a pulverized coal burner illustrated in Fig. 17 at high load.

Fig. 19 is a cross-sectional view of a pulverized coal burner according to a sixth embodiment of the present invention.

Fig. 20 is a front view of a pulverized coal burner illustrated in Fig. 19 from the side of the combustion chamber.

FIG. 21 is a sectional view (FIG. 21 (a)) and a front view (FIG. 21 (b)) of a pulverized coal burner according to a seventh embodiment of the present invention.

Fig. 22 is a sectional view (Fig. 22 (a)) and a front view (Fig. 22 (b)) of a pulverized coal burner according to an eighth embodiment of the present invention.

Fig. 23 is a cross-sectional plan view of the combustion chamber according to an embodiment of the present invention, illustrating the situation of flame formation by the configuration of the burners during angular fuel combustion at high load (Fig. 23 (a)) and at low load (Fig. 23 (b)) .

Fig. 24 is a cross-sectional top view of the combustion chamber according to an embodiment of the present invention, illustrating the situation of flame formation by the configuration of burners during tangential combustion of fuel at high load (Fig. 24 (a)) and at low load (Fig. 24 (b)) .

FIG. 25 is a sectional plan view of a combustion chamber according to an embodiment of the present invention, illustrating a torch configuration by burner configurations during the tangential combustion of a fuel at high load (FIG. 25 (a)) and at low load (FIG. 25 (b)).

Fig. 26 is a schematic schematic configuration of a conventional brown coal boiler, which shows a vertical front view (Fig. 2b (a)) and a section view from above (Fig. 26 (b)) of a combustion chamber.

Fig. 27 is a schematic diagram of a fuel burning apparatus according to an embodiment of the present invention.

Fig. 28 is a cross-sectional plan view of the fuel burning apparatus illustrated in Fig. 27.

29 is a schematic diagram of a pulverized coal boiler according to an embodiment of the present invention.

30 is a front view of an example of a burner chamber according to the prior art, from the side of the combustion chamber.

Fig - sectional top view of the combustion chamber corresponding to the prior art, illustrating the change in the combustion area in the combustion chamber in the process of reducing the load when the configuration of the burners corresponding to the angular combustion of fuel at high load (Fig (a)) and at low load ( Fig. 31 (b)).

Fig. 32 is a vertical sectional front view of a combustion chamber according to the prior art, illustrating the position of a flame-temperature detector mounted in a combustion chamber for monitoring the middle of the combustion chamber.

DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE PRESENT INVENTION.

Embodiments of the present invention are described below with reference to the accompanying drawings.

26 illustrates the configuration of the combustion chamber 41 of a conventional brown coal boiler. On Fig (a) presents a vertical front view of the combustion chamber 41 of the boiler, working on brown coal, with tangential combustion of fuel. FIG. 26 (b) is a sectional view from above of the combustion chamber 41 illustrated in FIG. 26 (a).

In a conventional brown coal boiler, off-gas having a temperature of about 1000 ° C. is removed from the top of the combustion chamber 41 through an exhaust gas channel 55 (FIG. 28). The fan-grinder 45 drains and grinds the brown coal supplied from the coal hopper 43. The heat transfer pipes of the superheater 59 (Fig. 29) and similar devices are located in the inner part of the combustion chamber 41. In the burner corresponding to angular fuel combustion and tangential fuel combustion, the fan- a chopper 45 is provided in each burner chamber 37 (FIG. 30).

(First Embodiment of the Present Invention)

Figures 1 and 2 show sections of a solid fuel burner (below simply a burner) according to a first embodiment of the present invention. Figure 1 illustrates a situation in which fuel ejected from the burner 42 at low load is burned in the combustion chamber 41. Figure 1 illustrates a situation in which fuel ejected from the burner 42 at high load is burned in the combustion chamber 41. Figure 3 shows a schematic diagram of the burner, illustrated in figure 1, from the side of the combustion chamber 41.

An oil heater 24, designed to facilitate combustion, is provided in the center of the burner 42. A central air supply pipe 10 for ejecting air is provided around the oil heater 24. A fuel atomizer 11 is provided around the central air supply pipe 10, having a channel coaxial with the central supply pipe 10 air and ejecting a fluid mixture of fuel conveying gas. Additional vents (not shown) or additional air supply tubes 12 are provided on the inner wall surface of the fuel atomizer 11 to which heated and / or compressed air is supplied. In the present invention, a plurality of additional air supply tubes 12 are provided along the inner wall surface of the fuel atomizer 11, as shown in FIG. 3, or in an alternative embodiment, a plurality of additional air vents are provided on the inner wall surface. The secondary air supply pipe 13 and the tertiary air supply pipe 14 (in some cases described below collectively referred to as the external air supply pipe) are aligned with the fuel atomizer 11 and are provided around the fuel atomizer 11 for air ejection. An obstacle called a ring flame stabilizer 23 is provided at the outer end (from the exit to the combustion chamber) of the fuel atomizer 11. An annular flame stabilizer 23 serves to counteract the passage of a stream 16 of a mixture of fuel and carrier gas (below the stream of pulverized coal) ejected from the atomizer 11 of the fuel and stream 17 of secondary air passing through the secondary air supply pipe 13. In accordance with this, the pressure on the far side along the processing chain (side of the combustion chamber 41) of the annular flame stabilizer 23 is reduced, as a result of which a stream is formed in this region, passing in a direction opposite to the direction of motion of the pulverized coal stream 16 and secondary air stream 17. This backward flow is called recirculation zones 19. The high-temperature gas generated by the combustion of the pulverized fuel passes into the recirculation zones 19 from areas located downstream of the process chain and remains here. The high-temperature gas is mixed with pulverized coal in a high-speed fuel stream 16 at the outlet of the burner into the combustion chamber 41. At the same time, the dusty coal particles are heated by heat radiation from the combustion chamber 41 and are ignited thereby.

The igniter oil heater 24 provided along the central axis of the central air supply pipe 10 is used to ignite the fuel when the burner 42 is started. A swirl 10a, designed to swirl the air ejected from the central air supply pipe 10, is provided at the end of the central air supply pipe 10. Air is supplied to the air box 26 for supplying air and then is supplied to the combustion chamber 41 through the secondary air supply pipe 13 and the tertiary air supply pipe 14. The swirlers 27 and 28, intended for swirling the air flows ejected from the secondary air supply pipe 13 and from the tertiary air supply pipe 14, are provided in the pipes 13 and 14, respectively.

The secondary air supply pipe 13 and the tertiary air supply pipe 14 are separated from each other by the baffle 29. The end of the baffle 29 forms a guide (sleeve) 25 to induce the ejection of the tertiary air stream 18 at an angle relative to the pulverized coal stream 16. The burner port 30 forming the wall of the combustion chamber 41 also serves as the outer wall of the tertiary air supply pipe 14. On the walls of the combustion chamber 41, water cooling pipes 31 are provided.

An element for narrowing the channel 32, designed to temporarily narrow the cross section of the channel in the atomizer 11 of the fuel and to expand the specified cross section to the original value, is provided on the inner wall of the atomizer 11 of the fuel. In addition, an obstacle 33 for concentrating fuel to the side surface of the baffle 22 of the fuel atomizer is provided on the outside of the central air supply tube 10. Obstacle 33 is located on the side lower in the process chain (on the side of the combustion chamber) of the channel narrowing member 32.

The channel narrowing element 32 has an effect where the stream of fuel particles (pulverized coal), which has a greater inertia than the stream of gas transporting fuel (exhaust gas), is focused in the region of the central axis of the burner. In addition, the obstacle 33 provided downstream from the channel narrowing element 32 has the effect that the stream of fuel particles (pulverized coal) focused in the central axis by the channel narrowing element 32 is expanded by the obstacle 33 and then passes through the channel of the atomizer 11 of the fuel.

In this case, since the flow of particles of fuel (pulverized coal), which expands and then passes through the channel of the atomizer 11 of the fuel, has more energy than the flow of gas transporting fuel (exhaust gas), the flow of particles of fuel (pulverized coal) is concentrated in the inner lateral region the walls of the atomizer 11 of the fuel and passes towards the exit. This concentrated pulverized coal stream in the region of the side wall of the fuel atomizer 11 simply engages in contact with external air (combustion air) near the outlet of the atomizer 11 and further enters into contact with the high-temperature gas of the recirculation zones 19, which are formed downstream from ring stabilizer 23 of the flame, and due to this is simply ignited.

In the present invention, described below, there are provided configurations of burner 42 and a combustion method in which the exhaust gas is used as a fuel-transporting gas and in which the oxygen concentration in the pulverized coal stream 16 is low. Such a combustion method is applicable, for example, for burning brown coal and lignite.

As indicated above, low-grade coal, such as brown coal and lignite, has a high content of volatile substances and moisture. Such coal has a low calorific value and, in addition, is difficult to grind. In addition, its ash has a low melting point. The high content of volatiles simply causes spontaneous ignition during storage and grinding in air. To prevent such problems when grinding and burning brown coal and lignite, a mixture of exhaust gas and air having a low oxygen concentration is used as a gas transporting fuel. In this case, the residual heat in the exhaust gas contributes to the evaporation of moisture from pulverized coal.

However, the burning rate of brown coal and lignite is lower in an atmosphere with a low oxygen concentration than in an air atmosphere. Thus, when transporting pulverized coal, for example brown coal and lignite, by means of a transporting gas having a low oxygen content, the burning rate depends on the speed of mixing brown coal and lignite with air. This results in a lower burning rate than the burning rate of coal, which can be carried out in an air atmosphere. Accordingly, when burning brown coal and lignite with a low load of the burner 42 with a low burning rate of fuel, there is simply a release and extinguishing of the flame compared to burning of coal. In addition, the time required for burning brown coal and lignite is longer than for burning coal. Thus, it is necessary to accelerate the mixing of fuel with air. With an increase in the amount of fuel burned, that is, when burning brown coal and lignite under high load with good mixing with air, a high concentration of volatile substances causes an increase in the amount of combustion in the vicinity of burner 42. Accordingly, the heat load near the burner 42 locally increases and, therefore , the temperature of the design of the burner and the wall of the combustion chamber rises due to heat radiation. This makes it possible that the ash formed as a result of combustion coheses and melts on the burner structure and the wall of the combustion chamber, causing their slagging in accordance with this. The lower melting point of brown coal ash and lignite accelerates the slagging of the burner structure and the combustion chamber wall.

In the present embodiment, the above problem caused by the difference in fuel combustion conditions at high load and low load of burner 42 when using low-grade coal is solved by adjusting the position of the flame formation 20 depending on the load of the burner. That is, at high load, the flame 20 is formed in a position spaced a greater distance from the burner in the furnace. In contrast, at low load, a flame 20 is formed, starting from the exit of the fuel atomizer 11. At low load due to the low heat load on the combustion chamber, the temperature of the burner 42 and the walls of the combustion chamber does not rise as high as in the case of a high load, even if a flame 20 is formed near the burner 42 and the wall of the combustion chamber. Thus, slagging does not occur on the burner structure and the wall of the combustion chamber.

In order to form a flame torch 20, starting from the exit of the fuel atomizer 11 at low load, in the present invention, in addition to the fact that high-temperature gas is forced to be in the recirculation zones 19 formed below the processing chain from the ring flame stabilizer 23, air is supplied to the burner through additional ventilation holes or tubes 12 for supplying additional air, thereby increasing the concentration of oxygen in the stream 16 of pulverized coal near the annular stabilizer 23 of the flame. Due to this, the burning rate is increased in comparison with the case of a low oxygen concentration, thereby accelerating the ignition of the fuel particles. Accordingly, a flame torch 20 is formed starting from the vicinity of the fuel atomizer 11.

In addition, the air supply through the central air supply tube 10 also increases the oxygen concentration in the pulverized coal stream 16, thereby accelerating the ignition of the pulverized coal. In this case, it is preferable that the swirl 10a is provided in the central air supply tube 10, as shown in FIG. 1, in order to swirl the central air stream 15, thereby accelerating mixing with the pulverized coal stream 16. If the central air stream 15 is swirling, then the air stream 15 passing from the central air supply tube 10 expands outwardly by the action of centrifugal forces, whereby the flow rate directed towards the center of the combustion chamber is reduced. In accordance with this, the residence time of pulverized coal near the exit of the burner increases. As a result, combustion starts near burner 42.

The central air supply tube 10 and additional ventilation holes or additional air supply tubes 12 are preferably located upstream of the outlet of the fuel atomizer 11. In this case, the position of the central air supply tube 10 and the position of the additional air vents and additional air supply tubes 12 in the fuel atomizer 11 are preferably arranged so that the residence time of the pulverized coal in the atomizer 11 becomes shorter than the ignition delay time of the pulverized coal. The purpose of this is to prevent flame propagation in the opposite direction and damage from burning in the fuel atomizer 11 caused by ignition of pulverized coal in the atomizer 11 of the fuel. The measures used are: setting the ignition delay time (approximately 0.1 second) of gaseous fuel, the delay time of which is shorter than the ignition delay time of pulverized coal; and flow rates of 10-20 m / s in the atomizer 11 of the fuel. In this case, the distance between the outlet of the fuel atomizer 11 and the outlet of the central air supply tube 10 and the distance between the outlet of the fuel atomizer 11 and the outlet of the additional ventilation holes and the additional air supply tubes 12 was set to be approximately 1 m or less.

At high load, the heat load near the burner decreases due to the formation of a torch in a position far from the burner. For this purpose, in the present invention, the air supply from the additional ventilation openings or additional air supply pipes 12 is reduced compared to the case of a low load. On the other hand, the air supply from the central air supply tube 10 is increased, while the flow rate is set higher than the flow rate of pulverized coal 16 in the fuel atomizer 11. A decrease in the additional air supply reduces the oxygen concentration in the pulverized coal stream 16 near the annular flame stabilizer 23 compared with the case of low load, thereby slowing down the burning rate. In accordance with this, the temperature of the recirculation zones 19, formed lower in the process chain from the annular flame stabilizer 23, becomes lower, thereby suppressing heat radiation on the burner structure. In addition, increasing the air flow rate from the central air supply tube 10 increases the flow rate of pulverized coal 16 at the outlet of the fuel atomizer 11. Accordingly, the residence time of the fuel particles near the burner becomes shorter. As a result, most of the fuel ignites in a position far from the burner 42. Due to this, heat radiation from the flame plume is reduced and slagging of the burner structure and the combustion chamber wall is suppressed.

In the present embodiment, a swirler 10a is provided in the central air supply tube 10 in order to swirl the central air stream 15. Due to this, deviating from the burner 42, the central air stream 15 expands outward, whereby the flow rate decreases. In accordance with this, the speed of the air flow is balanced with the speed of flame propagation to a position far from the burner 42, in accordance with which stable combustion of pulverized coal is ensured.

In addition, in the present invention, recirculation zones 19 are formed downstream from the annular flame stabilizer 23 and then part of the fuel burns in the recirculation zones 19. Flames in this area serve as a starting torch. The resulting starting torch can stably supply high-temperature gas to the torch formed in the combustion chamber 41 in a position far from the burner 42, thereby stabilizing the flame in a position far from the burner 42 and, therefore, reducing the possibility of extinguishing the flame.

To reduce the concentration of NO _x in the exhaust gas generated by the combustion of pulverized coal, it is preferable to adjust the amount of air so that the air coefficient for volatiles (the ratio of the total amount of air supplied from the fuel atomizer 11, the central air supply pipe 10 and additional ventilation holes or tubes 12 supply of additional air to the amount of air required for complete combustion of volatile substances contained in the fuel) was 0.85-0.95. Most of the pulverized coal is mixed with the air supplied through the atomizer 11 of the fuel, and then burns (the first stage). Then the fuel gas is mixed with the secondary air stream 17 and the tertiary air stream 18, and then burns out (second stage). If an air channel 49 is provided (see FIG. 27) for supplying air downstream from the burner to the combustion chamber 41, the fuel gas is mixed with the air supplied from the air channel 49 and then completely burned out (third step). Volatile substances contained in the fuel burn out at the first stage, since their burning rate is higher than the burning rate of bound carbon.

In this case, the air coefficient for volatile substances, of 0.85-0.95, causes a lack of oxygen concentration, but accelerates the ignition of pulverized coal. The combustion of pulverized coal is carried out at a high flame temperature. Due to the chemically reducing combustion of pulverized coal, provided that there is a lack of oxygen in the first stage, NO _x generated from nitrogen contained in pulverized coal and air is converted to harmless nitrogen, resulting in a decrease in the concentration of NO _x in the exhaust gas from the combustion chamber 41 In addition, high temperature accelerates the reaction in the second stage, thereby reducing the amount of unburned carbon. Table 1 shows the results of comparing the concentration of NO _x in the exhaust gas at the outlet of the combustion chamber when the amount of supplied air changes. In this case, the fuel used was brown coal, and the fuel coefficient of (bound carbon) / (volatiles) was 0.82.

Table 1 State A Condition B Amount of fuel delivered (at rated load) one hundred% one hundred% The oxygen concentration in the gas transporting the fuel (%) 10 10 Air ratio for volatiles in fuel Carrier gas 0.26 0.26 BUT Central air 0.48 0.53 AT Additional air 0.05 0.05 FROM General (transporting gas + central air + additional air) 0.79 0.84 D Outside air (secondary air + tertiary air) 0.67 0.67 E Air ratio for fuel (volatiles + bound carbon) Common to the burner (conveying gas + central air + additional air + external air) 0.80 0.82 Air supplied through the air duct 49 0.40 0.40 NO _x concentration at the outlet of the combustion chamber (ppm: equivalent to 6% oxygen concentration) 165 150

In state B, the air coefficient for volatile substances (column D in table 1) becomes 0.84 with a value of 0.79 in state A, and the concentration of NO _x decreases.

The burner 42 according to the present embodiment is a cylindrical burner comprising a central air supply pipe 10, a fuel atomizer 11, additional air supply pipes 12, a secondary air supply pipe 13 and a tertiary air supply pipe 14, each of which is cylindrical and arranged concentrically as shown in the front view shown in figure 3, from the side of the combustion chamber. However, the fuel atomizer 11 may be rectangular. In addition, as shown in the front view of the burner shown in FIG. 4, from the side of the combustion chamber, the fuel atomizer 11 may be surrounded by at least a portion of the external air supply pipe, for example, secondary air supply pipe 13 and tertiary supply pipe 14 air. In addition, as shown in the cross-section of the burner shown in FIG. 5, external air can be supplied by means of a single tube (secondary air supply tube 13) and further can be supplied by three or more tubes (not shown). In the present invention, as shown in FIGS. 1 and 2, a channel constriction element 32 is provided in the fuel atomizer 11 to provide a channel constriction and an obstacle 33 for concentrating the fuel particles to the side of the external partition 22 of the fuel atomizer 11. However, a similar effect was obtained even on burner 42 (FIG. 5) without these structures.

In addition, in the present invention, as shown in FIGS. 1 and 2, an annular flame stabilizer 23 is provided at the end of the outer baffle 22 of the fuel atomizer 11. However, a burner 42 without an annular flame stabilizer 23, as shown in FIG. 5, may be provided with a pipe expansion member 70 designed to increase the rate of swirling of the external air flow from said external air supply pipe to be ejected at a deflection angle of 45 ° or less, relative to the central axis of the burner (secondary air stream 17), forming, in accordance with this, recirculation zones 19 downstream from the end of the external partition 22.

Figure 6 illustrates a burner, which is a modified burner 42, corresponding to a variant implementation of the present invention, illustrated in figure 1. The air supply section for the additional air supply tubes 12 may be connected to a specially designed combustion air supply device for supplying combustion air, but not connected to the air box 26 in this case shown in FIG. 6. If the air supply section for the additional air supply pipes 12 is connected to a specially designed combustion air supply device, then oxygen-rich air having an increased oxygen concentration or pure oxygen can simply be supplied depending on the ignition of pulverized coal and depending on the load devices for burning fuel. In addition, a device for adjusting the flow rate of combustion air provided for a specially designed combustion air supply device provides easy control of the feed rate.

(Second Embodiment of the Present Invention)

7 is a sectional view of a burner 42 according to a second embodiment of the present invention. Figure 7 illustrates the situation of the burner when the combustion chamber 41 is operating at high load. The second embodiment differs from the first embodiment in that the position of the swirl 10a located in the central air supply tube 10 can be offset. The burner operation situation of this embodiment of the present invention at low load is similar to the burner operation of the first embodiment at low load, illustrated in FIG. In this case, the swirl 10a is biased toward the end of the central air supply tube 10. The difference in the burner operating situation of the present embodiment at high load from the first embodiment at high load, illustrated in FIG. 2, is that the swirl 10a is biased to the side upstream of the central air supply pipe 10. An additional difference of the present embodiment from the first embodiment is that as the swirl 10a is shifted to a side higher in the processing chain of the central air supply tube 10, the cross section of the central air supply tube 10 becomes larger. This configuration reduces the ratio of the area covered by the swirl 10a to the cross-sectional area of the tube compared to the case where the swirl 10a is located at the end (side down the processing chain) of the central air supply tube 10.

A case is described below where the burner 42 of the present embodiment changes the swirling speed of the central air stream 15 under the condition of a high load of the combustion chamber 41.

At high load, in contrast to the first embodiment of the present invention, the swirl moves to the side higher along the processing chain of the central air supply tube 10. Accordingly, a flame plume is formed in a position far from the burner, thereby reducing the heat load near the burner. For this purpose, in the present embodiment, the air supply from additional ventilation holes (not shown) or additional air supply pipes 12 is reduced at high load compared to the case of low load.

In addition, at high load, the area covered by the swirl 10a in the central air supply tube 10 increases compared with the area at low load, thereby reducing the rate of swirling of the air flow from the central air supply tube 10. Accordingly, the central air stream 15 does not spread as well after ejection through the air supply pipe 10 into the combustion chamber 41, as in the case of a high swirl intensity. Thus, the residence time of the fuel particles near the burner becomes shorter and, therefore, the amount of fuel burned near the burner is reduced. Due to this, the heat radiation from the flame torch to the structure of the burner and the wall of the combustion chamber is reduced and the slagging of the structure of the burner and the wall of the furnace chamber is suppressed. At this very time, the temperature of the recirculation zones 19 located downstream from the annular flame stabilizer 23 becomes lower in accordance with a decrease in heat radiation from the flame plume.

In the present embodiment described above, there was an effect in the case of a change in the swirling speed of the central air stream 15. However, in addition to this change, the amount of air supplied to each of the air supply tubes 10-14 can be changed as described above in the first embodiment . The effect is the same as in the case of the first embodiment.

The present embodiment is a case in which the air flow ejected from the central air supply tube 10 is twisted by means of a swirler 10a, in which the blades inclined relative to the air flow create a swirl intensity. In addition, in the present embodiment, the spin intensity is changed by changing the position of the swirl 10a in the central air supply tube 10 and, accordingly, by changing the ratio of the area occupied by the swirl 10a to the cross-sectional area of the tube. However, the spin intensity can be changed by changing the angle of inclination of the swirl blades. Furthermore, the spin intensity can be changed by a method in which, as shown in cross section of the central air supply pipe 10 illustrated in FIG. 8, the pipe 52 located upstream of the central air supply pipe 10 is divided into two tubes 60a and 60c and into which air is introduced in a tangential direction relative to the cross section of the central air supply tube 10. In this case, the swirl intensity is canceled out at high load by using two opposed tubes 60a and 60b, while the swirl intensity is increased at low load by using mainly one of the two tubes 60a and 60b to introduce air.

(Third Embodiment of the Present Invention)

Figure 9 shows a section of a burner for burning solid fuels, such as brown coal and lignite, corresponding to the third embodiment of the present invention. Figure 10 shows a front view of the burner from the side of the combustion chamber.

A fluid mixture of pulverized coal fuel and exhaust gas is fed into the combustion chamber 41 through a fuel atomizer 11. An L-shaped annular flame stabilizer 36 having L-shaped protrusions directed inward toward the outlet of said fuel atomizer is provided at the end of the fuel atomizer 11. Recirculation zones 19 are formed downstream of the stabilizer, so that a flame is formed starting from the vicinity of the burner. The burner illustrated in FIG. 9 is characterized in that additional ventilation holes (not shown) or additional air supply tubes 12 are provided so that ignition air is introduced between the L-shaped protrusions of the ring flame stabilizer 36 (see FIG. 10). Due to this, ignition is simply initiated around each of the protrusions of the ring flame stabilizer 36 (ignition takes place lower in the process chain from the L-shaped protrusions of the ring flame stabilizer 36).

(Fourth Embodiment of the Present Invention

11 and 12 are sectional views of a burner 42 according to a fourth embodiment of the present invention. Figure 11 illustrates the situation in which the fuel ejected from the burner 43 at low load burns in the combustion chamber 41. Figure 12 and illustrates the situation in which the fuel ejected from the burner 43 at high load burns in the combustion chamber 41 In Fig.13 shows a schematic view of the burner 42, illustrated in Fig.11, from the side of the combustion chamber 41.

In the burner 42 according to the fourth embodiment, an oil blower 24 is provided in the center to facilitate ignition. A fuel atomizer 11 for ejecting a fluid mixture of fuel and carrier gas is provided around an oil blower 24. A plurality of additional air vents (not shown) or additional air supply tubes 12 are provided along the inner region of the outer surface 22 of the wall of the fuel atomizer 11. The secondary air supply pipe 13 and the tertiary air supply pipe 14, coaxial with the fuel atomizer 11 and intended to supply air flow, are provided around the fuel atomizer 11. An annular flame stabilizer 23 is provided at the outer end (exit side to the combustion chamber) of the wall surface of the atomizer 11 of the fuel. An annular flame stabilizer 23 serves to counteract both the pulverized coal stream 16 ejected from the fuel atomizer 11 and the secondary air stream 17 passing through the secondary air supply pipe 13. Accordingly, the pressure is reduced on the side downstream of the process chain (combustion chamber side 41) of the annular flame stabilizer 23, whereby recirculation zones 19 are formed in this region in the opposite direction to the pulverized coal stream 16 and the secondary air stream 17. In the recirculation zones 19, the fuel particles are heated by heat radiation from the combustion chamber 41 and are thereby ignited.

If the guide 25, designed to limit the ejection of external air outward relative to the Central axis of the burner 42, is provided at the outlet of the external air supply pipe (secondary air supply pipe 13, tertiary air supply pipe 14 and the like), then recirculation zones 19 are formed more just in conjunction with the annular flame stabilizer 23.

The igniter-assisted oil blower 24 provided along the central axis of the fuel atomizer 11 is used to ignite the fuel when the burner 42 is started. The swirlers 27 and 28, designed to swirl the air flows ejected from the secondary air supply pipe 13 and the tertiary air supply pipe 14, are provided in the pipe 13 of the secondary air supply and of the tertiary air supply tube 14, respectively.

The secondary air supply pipe 13 and the tertiary air supply pipe 14 are separated from each other by a partition 29. The end of the partition 29 forms a guide 25 for guiding the tertiary air stream 18 in an outward direction relative to the pulverized coal stream 16. The burner port 30 forming the wall of the combustion chamber 41 also serves as the outer wall of the tertiary air supply pipe 14. On the walls of the combustion chamber 41, water cooling pipes 31 are provided.

An element for narrowing the channel 32, intended to narrow the channel in the atomizer 11 of the fuel, is provided on the inner side of the septum 22 upstream of the atomizer 11 of the fuel. In addition, an obstacle 33 designed to concentrate fuel to the side surface of the baffle 22 of the fuel atomizer 11 is provided on the outside of the oil blower 24. The obstruction 33 is located on the side lower in the processing chain (on the side of the combustion chamber) of the channel narrowing element 32.

In the present embodiment described below, there are provided configurations of burner 42 and a method for burning brown coal and lignite, in which the exhaust gas from the combustion chamber 41 is used as a fuel transporting gas and in which the oxygen concentration in the pulverized coal stream 16 is low.

In the present embodiment, the problem of initiating and extinguishing the flame at low load and the problem of cohesion of ash and slagging of the burner design at high load caused by the difference in fuel combustion conditions at high load and low load of burner 42 when using low-grade coal, are solved by adjusting the position of the formation of the flame in the combustion chamber 41 depending on the load on the burner 42. That is, with a high load, a flame is formed in the combustion chamber 41 in a position far from the burner 42. In contrast, at low load, a flame is formed in the combustion chamber 41, starting from the vicinity of the exit of the fuel atomizer 11. At low load due to the low heat load of the combustion chamber 41, the temperature of the burner 42 and the walls of the combustion chamber 41 around the burner 42 does not rise as high as in the case of a high load, even if a flame is formed near the burner 42 and the walls of the combustion chamber 41. Thus, around the design of the burner and the walls of the combustion chamber 41 does not occur slagging.

In order to form a flame in the combustion chamber 41 starting from the vicinity of the exit from the atomizer 11 of the fuel at low load, in the present embodiment, in addition to the fact that high-temperature gas is forced to be in the recirculation zones 19, which are formed downstream from the ring flame stabilizer 23 and the guide 25 , air is supplied through additional ventilation holes (not shown) or additional air supply tubes 12, thereby increasing the oxygen concentration in the dust-like stream 16 coal near the annular flame stabilizer 23. By virtue of such work, the burning rate is increased in comparison with the case of a low oxygen concentration, thereby accelerating the ignition of the fuel particles. The flame torch, respectively, is formed in the combustion chamber 41, starting from the vicinity of the atomizer 11 of the fuel.

Additional vents (not shown) or additional air supply tubes 12 are preferably located upstream of the end (exit of the combustion chamber 41) of the fuel atomizer 11. In this case, the position of the additional ventilation openings or the additional air supply pipes 12 in the fuel atomizer 11 is preferably set so that the residence time of the fuel in the atomizer 11 is shorter than the ignition delay time of the fuel. The purpose of this is to prevent backfire and damage from burning in the fuel atomizer 11 caused by fuel combustion in the fuel atomizer 11. The measures used are: setting the ignition delay time (approximately 0.1 second) of gaseous fuel, the delay time of which is shorter than the ignition delay time of pulverized coal; and flow rates of 10-20 m / s in the atomizer 11 of the fuel. For example, the distance between the outlet of the fuel atomizer 11 and the exit of the central air supply tube 10 and the distance between the outlet of the fuel atomizer 11 and the outlet of the additional ventilation holes and the additional air supply tubes 12 are set to approximately 1 m or less.

With a high load of the combustion chamber 41, the heat load near the burner is reduced due to the formation of a flame in the combustion chamber 41 in a position far from the burner 42. For this purpose, in the present invention, air is supplied from additional ventilation openings (not shown) or additional air supply pipes 12 reduce compared to the case of low load. A decrease in the supply of additional air reduces the concentration of the pulverized coal stream 16 near the annular flame stabilizer 23 in comparison with the case of a low load, thereby slowing down the burning rate. Accordingly, the temperature of the recirculation zones 19, which are formed lower in the process chain from the annular flame stabilizer 23, becomes lower, thereby suppressing heat radiation on the burner structure 42, and accordingly, slagging is suppressed.

In the present embodiment, the recirculation zones 19 are formed downstream of the annular flame stabilizer 23, and part of the fuel is burned in the recirculation zones 10. Flames in this area serve as a starting torch. The obtained starting torch can stably supply high-temperature gas to the torch formed in the combustion chamber 41 in a position far from the burner 42, thereby stabilizing the flame in a position far from the burner 42 and, therefore, reducing the possibility of extinguishing the flame.

23 (a) illustrates a situation in which the flame of the burner 42 is formed in a position far from the recirculation zones 19 downstream from the ring stabilizer 23 of the flame, with a high load of the combustion chamber 41. In this case, to reduce the possibility of extinguishing Flames flame torches are preferably mixed with each other in the combustion chamber 41, thereby ensuring the possibility of stable combustion in the combustion chamber, as shown in sectional top view of a fuel combustion device (combustion chamber ry 41) using the burner 42 according to the present invention. 23 (a) illustrates a case where a burner 42 is located in each of the four corners of the combustion chamber 41. However, the operation is also the same in the case of opposed combustion of the fuel, in which the burner 42 is located in each of the opposite walls of the combustion chamber 41.

To reduce the concentration of NO _x in the exhaust gas generated by burning fuel, it is preferable to adjust the amount of air so that the air coefficient for volatile substances (the ratio of the total amount of air supplied from the atomizer 11 of the fuel, the Central tube 10 of the air supply and additional ventilation holes or tubes 12 supply of additional air to the amount of air required for complete combustion of volatile substances contained in the fuel) was 0.85-0.95. Most of the fuel is mixed with air supplied through additional ventilation holes or tubes 12 for supplying additional air to the atomizer 11 of the fuel, and then burns out (first stage). After that, the fuel gas is mixed with the secondary air stream 17 and the tertiary air stream 18, and then burns out (second stage). If an air channel 49 is provided (see FIG. 27) for supplying air downstream from the burner 42 to the combustion chamber 41, the fuel gas is mixed with the air supplied from the air channel 49, and then completely burns out (third step). Volatile substances contained in the fuel burn out at the first stage, since their burning rate is higher than the burning rate of bound carbon.

In this case, the air coefficient for volatile substances, of 0.85-0.95, causes a lack of oxygen concentration, but accelerates the combustion of fuel. Fuel is burned at a high flame temperature. Due to the chemically reducing combustion of the fuel under the condition that there is a lack of oxygen in the first stage, NO _x generated from the nitrogen contained in the fuel and air is converted to harmless nitrogen, resulting in a decrease in the concentration of NO _x in the exhaust gas from the combustion chamber 41. In addition , high temperature accelerates the reaction in the second stage, accordingly reducing the amount of unburned carbon. Table 2 shows the results of comparing the concentration of NO _x in the exhaust gas at the outlet of the combustion chamber 41 with a change in the amount of supplied air. In this case, the fuel used was lignite, and the fuel coefficient (associated carbon / volatiles) was 0.82.

In state B, the air coefficient for volatile substances (column C in table 2) becomes 0.85 with a value of 0.70 in state A, and the concentration of NO _x in the flare decreases.

table 2 State A Condition B Amount of fuel delivered (at rated load) one hundred% one hundred% The oxygen concentration in the gas transporting the fuel (%) 10 10 Air ratio for volatiles in fuel Carrier gas 0.50 0.50 BUT Central air 0.20 0.35 AT Additional air 0.70 0.85 FROM General (transporting gas + central air + additional air) 0.76 0.76 D Outside air (secondary air + tertiary air) Air ratio for fuel (volatiles + bound carbon) Common to the burner (conveying gas + central air + additional air + external air) 0.80 0.84 Air supplied through the air duct 49 0.40 0.40 NO _x concentration at the outlet of the combustion chamber (ppm: equivalent to 6% oxygen concentration) 170 155

The burner 42 according to the present invention is a cylindrical burner comprising a fuel atomizer 11, a secondary air supply pipe 13 and a tertiary air supply pipe 14, each of which is cylindrical and arranged concentrically, as shown in the front view of FIG. 13, from the side combustion chamber. However, the fuel atomizer 11 and the condenser may be rectangular. In addition, as shown in the front view of the burner 42 shown in FIG. 15 (front view from the side of the combustion chamber 41), the fuel atomizer 11 may be surrounded by at least a portion of an external air supply pipe, for example a secondary air supply pipe 13 and Tertiary air supply tubes 14. In addition, as shown in the burner illustrated in FIG. 15, additional ventilation openings or additional air supply pipes 12 can be positioned by one pipe along the inside of the wall 22 of the fuel atomizer 11.

In addition, as shown in sectional view of burner 42 shown in FIG. 16, external air may be supplied by means of a single tube (secondary air supply tube 13) or may be supplied by three or more tubes (not shown). In the present embodiment, as shown in FIGS. 11 and 12, a channel constriction element 32 is provided in the fuel atomizer 11 for narrowing the channel, and an obstacle 33 for concentrating the fuel particles on the inner side of the wall surface 22 of the fuel atomizer 11. However, a similar effect as in burner 42 illustrated in FIGS. 11-15 is obtained even without these structures.

In addition, in the present embodiment, as shown in FIGS. 11 and 12, an annular flame stabilizer 23 is provided at the end of the wall surface 22 of the fuel atomizer 11. However, as shown in FIG. 16, a guide 35 may be provided for guiding the external air stream (secondary air stream 17) outwardly with respect to the fuel atomizer 11, thereby generating recirculation zones 19 near the rear side (laterally from the middle combustion chamber 41) guide 35.

(Fifth Embodiment of the Present Invention)

17 and 18 are sectional views of a burner 42 according to a fifth embodiment of the present invention. 17 illustrates a situation in which fuel ejected from the burner 42 at low load burns in the combustion chamber 41. FIG. 18 illustrates a situation in which fuel ejected from the burner 42 at high load burns in the combustion chamber 41.

The main difference between this embodiment and the fourth embodiment is that neither an annular flame stabilizer 23 nor a guide 35 are provided on the end of the wall surface 22 of the fuel atomizer 11. To adjust the flame profile without the annular flame stabilizer 23 and the guide 35 in the secondary supply channel air provided swirl 27.

A flame torch is formed, starting from the exit from the atomizer 11 of the fuel at a low load of the combustion chamber 41. For this purpose, air is supplied through additional ventilation openings (not shown) or an additional air supply pipe 12, thereby increasing the oxygen concentration in the pulverized coal stream 16 near the septum 22 of the fuel atomizer 11. Thanks to this operation, the burning rate is increased in comparison with the case of a low oxygen concentration, thereby accelerating the ignition of the fuel particles. Starting from the vicinity of the fuel atomizer 11, a flame is generated, respectively.

In the present embodiment, the secondary air is intensively swirled (with a swirl coefficient of 1 or more) by means of a swirl 27 provided in the secondary air supply pipe 13. Due to the centrifugal force arising during twisting, the secondary air stream 17 after ejection expands in the direction of deviation from the pulverized coal stream 16. In this case, the pressure in the region between the pulverized coal stream 16 and the secondary air stream 17 drops, whereby recirculation zones 19 are formed in a direction opposite to the direction of the pulverized coal stream 16 and the secondary air stream 17. In addition, if a damper (not shown) is provided in the secondary air supply pipe 13 (not shown) to reduce the flow rate so as to reduce the secondary air flow rate to a value close to zero, then between the tertiary air stream 18 from the tertiary air supply pipe 14 and the stream 16 of pulverized coal, recirculation zones 19 are formed.

With a high load of the combustion chamber 41, the heat load near the burner 42 decreases due to the formation of a flame in the combustion chamber 41 in a position far from the burner 42. For this purpose, the air supply from the additional ventilation openings or additional air supply pipes 12 is reduced compared to a low case load. A decrease in the supply of additional air reduces the oxygen concentration in the stream of pulverized coal 16 near the surface 22 of the wall of the atomizer 11 of the fuel compared with the case of low load, thereby reducing the burning rate of the fuel. In addition, in the present embodiment, the spin intensity provided in the secondary air by the swirl 27 in the secondary air supply pipe 13 is reduced. The secondary air stream 17 after ejection from the secondary air supply pipe 13 then passes parallel to the pulverized coal stream 16, without correspondingly forming reverse circulation zones 19 in the region between the pulverized coal stream 16 and the secondary air stream 17. In addition, if the damper (not shown) provided in the secondary air supply pipe 13 is opened so as to increase the secondary air flow rate, the formation of reverse circulation zones 19 can be prevented between the pulverized coal stream 16 and the secondary air stream 17.

(Sixth Embodiment of the Present Invention)

FIG. 19 is a sectional view of a solid fuel burner 42 according to a sixth embodiment of the present invention. On Fig shows a front view of the burner 42 from the side of the combustion chamber 41.

A fluid mixture of fuel and exhaust gas is led to the combustion chamber 41 through a fuel atomizer 11. An annular flame stabilizer 36 with L-shaped protrusions is provided at the end of the fuel atomizer 11. Downstream of the process chain (inside the combustion chamber 41), recirculation zones 19 are formed from the stabilizer, whereby a flame is generated starting from the vicinity of burner 42. The burner illustrated in FIG. 19 is characterized in that additional ventilation holes (not shown) or tubes 12 additional air supply (see FIG. 20) is provided so that combustion air is introduced between the L-shaped protrusions of the annular flame stabilizer 36. Due to this, combustion is simply initiated around each of the L-shaped protrusions of the annular flame stabilizer 36 (ignition takes place lower in the process chain from the L-shaped protrusions of the annular flame stabilizer 36).

(Seventh Embodiment of the Present Invention)

The seventh embodiment of the present invention is described below. On Fig shows a section of a burner corresponding to the seventh variant of implementation. On Fig (a) presents a section of the burner, while on Fig (b) presents a front view of the burner from the side of the combustion chamber.

The fluid mixture 1 of pulverized coal and carrier gas (primary air) is led to the combustion chamber 41 through a fuel atomizer 11. An annular flame stabilizer 36 with L-shaped protrusions is provided at the end of the fuel atomizer 11. Downstream of the stabilizer, recirculation zones 19 are formed, due to which, starting from the vicinity of the burner, a flame is formed.

An obstacle 33 is provided inside the fuel atomizer 11. The obstruction 33 increases the concentration of pulverized coal near the annular flame stabilizer 36, thereby accelerating the ignition. Combustion air (secondary air stream 17 and tertiary air stream 18) is led around the fuel atomizer 11 from the air box 26. The tertiary air stream 18 is properly swirled by means of a swirl 28, thereby optimizing combustion conditions with a reduced NO _x content. In addition, the tertiary air stream 18 expands outwardly through the guide 29, prompting in accordance with this the creation of a so-called lack of air condition in which there is insufficient air in the center of the flame. Accordingly, fuel is burned with reduced NO _x formation.

The burner illustrated in FIG. 21 is characterized in that between the obstruction 33 and the inner wall of the fuel atomizer 11, additional ventilation holes (not shown) and additional air supply tubes 12 are provided. Thus, additional ignition air is supplied to the pulverized coal stream concentrated by an obstruction 33 at the inner side of the wall of the fuel atomizer 11, and therefore, the oxygen concentration increases, while the pulverized coal concentration is maintained at a predetermined concentration level or higher. This improves flammability. An oil blower 24 is provided on the central axis of the burner 42, used to start the burner 42. Between the obstacle 33 and the annular flame stabilizer 36 at the end of the atomizer 11, a mixing region S is provided for mixing the fluid mixture with additional air to provide ignition. Due to this, the fluid mixture is sufficiently mixed with additional air 21 for ignition. Between the L-shaped cutaway teeth of the annular flame stabilizer 36 (see FIG. 21 (b)), additional vents or additional ignition air supply tubes 12 are provided. Due to this, ignition is easily initiated around each of the L-shaped protrusions of the annular flame stabilizer 36 (ignition takes place lower in the process chain from the L-shaped protrusions of the annular flame stabilizer 36).

A guide 36 ', designed to expand the direction of ejection of external air, can be provided at the outlet of the channel of the external air supply pipe (secondary air stream 17, tertiary air stream 18 and similar flows), and the recirculation zones 19 are formed more easily when the guide 36' interacts with the annular 36 flame stabilizer.

(Eighth Embodiment of the Present Invention)

The burner 42 corresponding to the eighth embodiment illustrated in FIG. 22 (FIG. 22 (a) is a sectional view of the burner 42, and FIG. 22 (b) is a front view of the burner from the combustion chamber side), characterized in that the additional air 67 for ignitions are introduced from the supply line 66, specially designed for additional ventilation holes (not shown) or additional air supply tubes 12 for ignition, through additional ventilation holes (not shown) or additional air supply tubes 12 for ignition I and S in the mixing zone, designed for mixing the fluid mixture in the nebulizer 11 with the additional fuel 67 to ignite the air.

In the burner 42 illustrated in FIG. 22, the additional ignition air 67 introduced from the supply line 66 may have a pressure different from the pressure of the air supplied from the air box 26, thereby allowing free choice of the size of the additional ventilation openings (not shown) or tubes 12 for supplying additional air. In addition, a device (not shown) for adjusting the flow rate of ignition air may be provided in a specially designed auxiliary ignition air supply line 66, thereby allowing a simple adjustment of the feed rate. When using oxygen-enriched gas as additional air 67 for ignition, the flammability is improved.

FIG. 23 is a sectional view of a top view of a combustion chamber 41 using burners in accordance with any of the above embodiments of the invention for angular fuel combustion.

In general, when the burners are arranged in accordance with the angular combustion of fuel, a horizontal section for the burner chamber 37 is provided at each corner of the combustion chamber 41. At high load of the combustion chamber 41, as shown in Fig. 23 (a), the high-speed flow from each burner in the burner chamber 37 forms an outlet section 38 near the exit of the burner, thus forming a region of stable combustion in the combustion chamber 41.

In the example of operation of the burner in accordance with the angular combustion of fuel illustrated in FIG. 23, the tertiary air flow rate 18 of the external tertiary air supply tube 14 contributing to the formation of a stable combustion region in the combustion chamber is 50 m / s or more, while the velocity of the stream 16 of pulverized coal supplied by the exhaust gas is 5-30 m / s. And the air flow rate of the Central tube 10 of the air supply, designed to accelerate the ignition of the fuel, is 5-20 m / s.

At low load of the combustion chamber 41, as shown in FIG. 23 (b), the distribution coefficient and the swirl intensity of the combustion air are controlled so that each burner forms a flame flame F of an automatically stabilizing type. On Fig illustrates an embodiment in which fuel is supplied to the combustion chamber 41 of the four burner chambers 37, each formed in the side wall of the combustion chamber 41. In Fig. 25 (in Fig. 25 (a) at high load, and Fig. 25 (b) at low load) illustrates an embodiment in which fuel is supplied to the combustion chamber 41 of six burner chambers 37, each provided in a side wall of the combustion chamber 41.

According to the above-described installation, near the burner 42 there is a low oxygen concentration and there is no heat source, for example, high-temperature gas circulation at a high level. Accordingly, the fuel does not ignite, so that an exhaust section 38 is formed. In the middle of the combustion chamber 41, the fuel is mixed with high-speed flows from other burners 42 and with air from the tertiary air supply pipe 14, thereby forming a region of stable combustion, and therefore stable combustion of fuel. The function of the tertiary air supply tube 14 at high load, as in the prior art, is to stabilize the formation of a stable combustion region. For this purpose, the flow velocity is preferably 50 m / s or more.

In short, in the present invention, in the combustion chamber 41 in accordance with the angular or tangential combustion according to the prior art, the exhaust section 38 is formed in a high-speed fuel flow near the burner 42 at high load, thereby forming a stable combustion region in the combustion chamber 41. In contrast, with a low load in a high-speed fuel stream, starting from the vicinity of the burner 42, an automatically stabilized flame is formed. This work provides applicability in a wide range of loads of the combustion chamber 41.

It is more characteristic that the water-cooled design of each wall surface of the combustion chamber is not modified, but part of the burner chamber 37 is modified in the design of the burner containing a fuel channel; and many channels for combustion air. Then, the distribution of combustion air and the spin rate of the high-speed fuel flow and the high-speed combustion air flow are adjustable. In this case, the operation is regulated depending on the low or high load of the combustion chamber.

In the above description, the water-cooled wall structure is not modified, but one part of the burner chamber 37 is modified. However, the present invention is applicable in the case of a water-cooled wall structure provided between adjacent burners 42 in a newly created boiler.

On Fig is a schematic diagram of a device for burning fuel when using burners operating on coal, such as brown coal and lignite, corresponding to the present invention. On Fig shows a section view from above of the device illustrated in Fig.27. The following is a description made with reference to FIGS. 27 and 28.

The combustion chamber 41 of the device for burning fuel in each corner contains two vertical rows of burners 42. Each burner 42 is positioned so that it is horizontally directed towards the middle of the combustion chamber 41. Coal and similar fuel are supplied from the fuel hopper 43, through the device 44 for feeding coal and into the fan-grinder 45. Coal, crushed by means of the fan-grinder 45, is fed through the fuel line 54 to the burner 42. In this case, the exhaust gas discharged from the upper part of the combustion chamber 41 is mixed with coal in Nala 55 feeding the exhaust gas is located downstream from the device 44 to the coal feed, and then introduced into the fan-crusher 45. When mixed with the high temperature gas for the combustion of coal from the coal evaporates moisture. In addition, since the oxygen concentration decreases, spontaneous ignition of the coal and the explosion when the coal is heated during the grinding process in the grinding fan 45 are suppressed. In the case of brown coal, the oxygen concentration is usually 8-15%. The air supplied to the burner 42 and to the air channel 49, located downstream of the process chain, is supplied by the blower 46. In this case, a two-stage fuel combustion circuit is used, in which the burner 42 supplies air in an amount that is less than the amount required for complete combustion of the fuel, and in which the air duct 49 delivers a shortage of air. However, a two-stage fuel combustion scheme is also possible in which there is no air channel 49 and in which the burner 42 supplies all the necessary amount of air.

In the burner 42, depending on the load of the fuel combustion device (combustion chamber 41), the combustion method is changed. That is, at high load, the heat load near the burner decreases due to the formation of a flame in a position far from the burner 42. In contrast, with a low load, a flame is formed starting from the exit of the fuel atomizer 11. In this case, for the safe operation of the device for burning fuel, it is necessary to control the flame. In the present invention, since the combustion method is changed depending on the load, the method for monitoring the flame of the flame is preferably changed depending on the load. That is, at low load, since the flame is formed independently in each burner 42, a flame-temperature detector 47 must be provided in each burner 42. In contrast, at high load, for monitoring the flame, which is formed in a position far from the burner 42, a flame-temperature detector 48 is required for monitoring the middle of the combustion chamber 41. Depending on the load and method of burning fuel, select the appropriate signal from the flame-temperature detectors Sectors 47 and 48, in accordance with which the current control of the torch.

In addition, thermometers (not shown) or flame-temperature detectors (not shown) may be provided in the walls of the combustion chamber or burner walls 42 operating on pulverized coal to reduce slagging of the burner structure and the walls of the combustion chamber under high load, in accordance with which In response to a signal from such devices, the flow rate of additional air and the flow rate of central air can be adjusted.

29 illustrates a configuration in which various burners for burning coal, for example brown coal and lignite, corresponding to any of the above embodiments of the present invention, are used in a pulverized coal boiler system.

The pulverized coal boiler illustrated in FIG. 29 has a burner configuration 42 corresponding to a two-stage fuel combustion circuit and includes an air duct 49. Many burners 42 are located in the combustion chamber 41 in three vertical rows of five pieces in each row. The horizontal arrangement of the burners of the combustion chamber 41 is not shown. The number of burners 42 and their location is determined by the ability (maximum burning rate of pulverized coal, boiler capacity and similar parameters) of one burner and boiler design.

The burners 42 of each stage are located in the air box 26. A spray gun designed to eject the ignition-promoting oil with exhaust gas and air is provided in the burner 42. The ignition-promoting oil is supplied through a distributor 58 in the atomizer 24 of the oil of each burner. The combustion air 51, heated by means of the heat exchanger 52, becomes in accordance with this hot air, the temperature of which is approximately 300 ° C. The combustion air is introduced into the air box 26 after adjusting the flow rate through the damper 56. Then, the combustion air is ejected through each burner 42 into the combustion chamber 41. The combustion air 51 is additionally supplied through the damper 57 to the air duct 49.

The off-gas is discharged through the off-gas channel 55 connected to the vicinity of the off-gas outlet at the exit of the combustion chamber, thereby supplying coal to the coal supply device 44. Pulverized coal is fed to the grinder fan 45 together with the conveying exhaust gas and ground here. The grain size distribution is then controlled and then pulverized coal is supplied to the burner 42. The grain size of the pulverized coal supplied to the burner 42, and its distribution is controlled depending on the load of the boiler. The wall surface of the combustion chamber 41, as a rule, has a water-cooled design to generate primary water vapor. The primary steam superheated by the steam heater 59 becomes superheated steam supplied to a steam turbine (not shown). A steam turbine is connected to an electric generator that generates electricity.

In the chimney to exhaust the exhaust gas of the pulverized coal boiler through the chimney 63, an exhaust gas purification apparatus comprising an NO _x removal device 60, an electric dust collector 61 and an SO _x removal device 62 is provided through the air.

The amount of combustion air supplied to each burner 42 is set to a value of 89-90 vol.% Of the theoretical amount of coal combustion air. The amount of air supplied subsequently from the air channel 49 is set equal to approximately 40-30 vol.% Of the theoretical amount of air for burning coal. Accordingly, the total amount of air is about 120 vol.% Of the theoretical amount of air for burning coal. Flame burning of the pulverized coal burner 42 is carried out using air, the amount of which is less than the theoretical amount of air, after which the unburned carbon of the fuel is burned in the air supplied subsequently.

Electricity generation by burning low-grade coal, for example brown coal and lignite, is carried out by means of a coal-fired power plant containing a combustion chamber having wall surfaces of the combustion chamber equipped with a plurality of burners 42 according to the present invention; a coal-fired boiler for generating water vapor by using the heat of combustion obtained by burning pulverized coal with burners 42; steam turbines driven by steam from the boiler; and an electric generator (not shown) driven by steam turbines.

INDUSTRIAL APPLICABILITY

The present invention provides a solid fuel burner and a method for burning fuel using a solid fuel burner that can provide stable combustion of a fuel over a wide load range of a combustion chamber from a high load condition to a low load condition even in in the case of burning poorly combustible fuels like low-grade coal, such as brown coal and lignite; devices for burning fuel, for example a combustion chamber, a heating furnace and a blast heater, using the specified burner and its control method; a solid fuel boiler and the system in which it is used; and a coal-fired power plant.

The present invention allows ignition of fuel in the vicinity of the burner, even if a gas with a low oxygen concentration is used as the transporting gas. Accordingly, even pulverized coal, for example brown coal having poor ash properties, can be quickly and efficiently burned near the exit of the burner. This allows a reduction in the NO _x content in the exhaust gas and prevents the ash from cohesion around the burner.

Claims (59)

1. A solid fuel burner containing a central air supply pipe for ejecting air, a fuel atomizer provided outside the specified central air supply pipe and ejecting a fluid mixture consisting of solid fuel and a transport gas, additional ventilation holes or additional supply pipes air provided in the inner surface of the fuel atomizer wall and ejecting air, and one or more external air supply tubes provided outside the specified fuel atomizer and ejecting combustion air. 2. A solid fuel burner according to claim 1, wherein the output of any one or said central air supply pipe and said additional ventilation holes or additional air supply pipes is located in a position located upstream of the burner process chain from the output of said fuel atomizer . 3. The solid fuel burner according to claim 1, wherein the heated and / or compressed air is connected to said additional ventilation openings or additional air supply pipes. 4. The solid fuel burner according to claim 1, in which, starting from the side upstream of the burner processing chain, an obstruction is provided on the outer wall surface of said central air supply tube, comprising a conical section having a gradually increasing cross section, and a conical section having a gradually decreasing cross section. 5. A solid fuel burner according to claim 1, wherein a channel constriction element is provided on the inner wall of said fuel atomizer for temporarily narrowing the cross section of the channel of said fuel atomizer, starting from the side upstream of the burner processing chain, and to expand the specified cross section to the original value. 6. A solid fuel burner according to claim 1, wherein a swirler is provided in said central air supply tube. 7. A solid fuel burner according to claim 1, wherein a swirler is provided in said external air supply pipe. 8. A solid fuel burner according to claim 1, wherein a guide is provided at the outlet of said external air supply pipe to limit the direction of ejection of external air. 9. The solid fuel burner according to claim 1, wherein an outlet pipe extension is provided at the outlet of said external air supply pipe to increase the rate of swirling of the external air flow from said external air supply pipe to eject at a deflection angle, equal to 45 ° or less, relative to the central axis of the burner. 10. A solid fuel burner according to claim 1, wherein an annular flame stabilizer is provided between said fuel atomizer and said external air supply pipe to resist an ejected flow of a mixture of solid fuel and air. 11. The solid fuel burner of claim 10, wherein an annular flame stabilizer is provided having L-shaped protrusions directed inward toward the outlet of said fuel atomizer. 12. The solid fuel burner according to claim 1, wherein the cross section of the channel down the process chain from said central air supply pipe is less than the cross section of the channel up the process chain from said central air supply pipe. 13. The solid fuel burner of claim 12, wherein the location of said swirler in said central air supply tube is movable in the direction of the central axis of the burner in said central air supply tube. 14. The solid fuel burner according to claim 1, wherein a swirler is provided in said central air supply tube for adjusting the rate of swirl of the air flow depending on the burning load. 15. The method of burning fuel when using a solid fuel burner according to claim 1, wherein the air ejection mode from the burner is supplied depending on the combustion load of a group of the air ejection mode, in which the air stream from said central tube is selected the air supply is ejected as a rectilinear high-speed flow or a weakly swirling high-speed flow, and an air ejection mode in which the air flow from said central air supply tube is ejected as a strongly swirling high speed stream. 16. The method of burning fuel according to clause 15, in which at a low burning load a highly swirling high-speed stream is ejected from the specified central air supply pipe, while at a high burning load from the specified central air supply pipe, a rectilinear high-speed stream or a slightly twisted high-speed stream is ejected. 17. The method of burning fuel according to clause 15, in which the combustion is carried out by adjusting the amount of air so that the ratio of the total amount of air supplied by the specified fuel atomizer, the specified Central air supply pipe and the specified additional ventilation holes or additional air supply pipes, to the amount of air required for complete combustion of the volatile substances of the fuel was maintained equal to 0.85-0.95. 18. The method of burning fuel using a solid fuel burner according to claim 1, wherein the ratio of the amount of air ejected from said central air supply pipe to the amount of air ejected from said additional ventilation holes or additional air supply pipes is adjusted depending on the burning load. 19. The method of burning fuel according to claim 18, wherein, at a low combustion load, the amount of air ejected from said central air supply tube is reduced, and at the same time, the contribution of the amount of air ejected from said additional ventilation holes or additional air supply tubes is increased, while at a high combustion load, the amount of air ejected from the specified central air supply tube is increased, and at the same time, the contribution of the amount of air ejected from the indicated additional air holes or additional air supply tubes. 20. A device for burning fuel using exhaust gas as a transport gas for solid fuel used in a solid fuel burner according to claim 1, and comprising a combustion chamber having a wall surface of the combustion chamber equipped with a plurality of said burners operating on solid fuel. 21. The device for burning fuel according to claim 20, in which many of these burners are located in the corners or in opposite surfaces of the side walls of the combustion chamber so as to form a pair or pairs of modules. 22. The device for burning fuel according to claim 20, in which the central tube of the air supply of the burner operating on solid fuel has a cylindrical shape and in which a pair of air supply tubes for supplying air are connected to the part upstream of the specified central tube air supply, and in which the specified pair of these air supply pipes are connected so that air is introduced in a tangential direction in each of the opposing positions of the cross-section circle of the specified Central air supply tubes. 23. The control method of the device for burning fuel according to claim 20, in which at a high load of combustion in the specified device for burning fuel, increase the amount of air ejected from the specified Central air supply pipe, and at the same time reduce the contribution of the amount of air ejected from these additional ventilation openings or additional air supply pipes, due to which, starting from a position far from the specified solid fuel burner, a solid flame torch is formed fuel, in which at a low burning load in said fuel burning device, the amount of air ejected from said central air supply pipe is reduced, and at the same time, the contribution of the amount of air ejected from said additional ventilation openings or additional air supply pipes is increased due to which is directly lower in the process chain from the outlet of the fuel atomizer of the specified solid fuel burner, a flame of solid fuel is formed wa. 24. The method of controlling the device according to item 23, in which in the specified burner that runs on solid fuel, or on the surface of the wall of the combustion chamber near the specified burner that runs on solid fuel, thermometers or flame-temperature detectors are provided, thereby controlling the amount and intensity swirling air ejected from said central air supply tube of said solid fuel burner, or in an alternative embodiment, the amount of air ejected from said additional ventilation openings or additional air supply pipes in response to a signal from these measuring instruments. 25. The control method of the device according to item 23, in which at high load the specified device for burning fuel, the combustion is carried out in a position that is 0.5 m or more away from the fuel atomizer exit on the central axis of the fuel atomizer in the combustion chamber, in which low load of the specified device for burning fuel, starting from a position located near the surface of the wall of the combustion chamber outside the outlet of the fuel atomizer, a flame of solid fuel is formed in the combustion chamber. 26. The device control method according to item 23, in which at high load the specified device for burning fuel by using flame-temperature detectors or by visual inspection, the torch is monitored in the middle of the combustion chamber where torches of solid fuel flame from the burners operating on solid fuel, while at a low load of the specified device for burning fuel, the torch formed near the exit of each burner operating on solid fuel is monitored e. 27. The device control method according to claim 23, wherein, at a high load of said fuel burning device, an identical amount of air is supplied to the two air supply pipes as to said central air supply pipe, while at a low load of said fuel burning device, two air supply tubes supply a different amount of air than to the specified central air supply tube, whereby depending on the high or low load, the central air swirl intensity is controlled th stream. 28. A coal-fired boiler comprising a combustion chamber having a wall surface equipped with a plurality of solid fuel burners according to claim 1, a superheater provided in said combustion chamber for boiling water to generate water vapor by using a flame torch, obtained by burning solid fuel in the specified combustion chamber. 29. A coal-fired boiler system, comprising a coal-fired boiler, according to claim 28, a chimney serving as an exhaust gas channel from said boiler, an exhaust gas purification device provided in said chimney, a pulverized coal transport device designed to transport coal in the form of pulverized coal to burners in the specified boiler, a device for controlling the supply of pulverized coal, designed to adjust the amount of pulverized coal supplied from the specified device for t ansportirovki pulverized coal to said burners, and a device for adjusting the air supply, for adjusting the amount of air ejected from said burners. 30. A coal-fired power plant comprising a combustion chamber having wall surfaces of the combustion chamber equipped with a plurality of solid fuel burners according to claim 1, a boiler for boiling water to produce water vapor by using the heat of combustion obtained by burning solid fuel by said burners, a steam turbine driven into rotation by the steam generated by said boiler, and an electric generator driven by said steam turbine. 31. A solid fuel burner comprising a fuel atomizer for ejecting a fluid mixture consisting of solid fuel and a carrier gas, additional ventilation holes or additional air supply tubes provided in an inner wall surface of said fuel atomizer and ejecting air. 32. A solid fuel burner according to claim 31, wherein the heated and / or compressed air is connected to said additional ventilation openings or additional air supply pipes. 33. The solid fuel burner of claim 31, wherein the outputs of said additional ventilation holes or additional air supply tubes are located on the side upstream of the burner processing chain from the outputs of said fuel atomizer. 34. The solid fuel burner of claim 31, wherein an obstacle is provided within the fuel atomizer comprising a section having a gradually increasing cross section and a section having a gradually decreasing cross section in the direction from side up in the burner process chain to side down the burner process chain. 35. The solid fuel burner according to claim 31, wherein a channel constriction element is provided on the inner surface of the wall of said fuel atomizer for temporarily narrowing the cross section of the channel of said fuel atomizer in the direction from the side up along the burner processing chain to the side down along the burner process chain and to expand the specified cross section to the original value. 36. The solid fuel burner of claim 31, wherein a swirler is provided in the external air supply pipe. 37. The solid fuel burner according to claim 31, wherein a guide is provided at the outlet of the external air supply pipe to restrict the direction of flow of external air ejected from the external air supply pipe. 38. The solid fuel burner of claim 31, wherein an annular flame stabilizer is provided between said fuel atomizer and the external air supply pipe to resist an ejected flow of a mixture of solid fuel and air. 39. The solid fuel burner of claim 38, wherein an annular flame stabilizer is provided that has L-shaped protrusions directed inward toward an end of a wall surface of said fuel atomizer. 40. The solid fuel burner of claim 34, wherein the exhaust gas is used as a gas transporting solid fuel and wherein the outlet from said additional ventilation openings or additional air supply tubes is located between a conical section of an obstacle having a gradually decreasing cross section , and ring flame stabilizer. 41. The solid fuel burner of claim 31, wherein the air supply section for said additional ventilation holes or additional air supply pipes is connected to air boxes for supplying compressed air to the external air supply pipe. 42. The solid fuel burner of claim 31, wherein the air supply section for said additional ventilation openings or additional air supply pipes is connected to a combustion gas supply device specifically adapted to supply combustion air to said combustion section air. 43. The solid fuel burner of claim 42, wherein said combustion air supply device is connected to means for supplying oxygen-rich gas or pure oxygen. 44. The burner operating on solid fuel according to claim 42, wherein said device for supplying combustion air is provided with a device for adjusting the flow rate for combustion. 45. The combustion method when using a solid fuel burner according to claim 31, wherein, at a low combustion load, the amount of air supplied from said additional ventilation openings or additional air supply pipes is increased, while at a high combustion load, the amount of air is reduced, supplied from these additional ventilation openings or additional air supply pipes. 46. The method of burning fuel according to item 45, in which at a low combustion load, reduce the amount of air supplied from the external air supply pipe, which of these external air supply pipes is closest to the specified fuel atomizer, or alternatively increase its swirl intensity and with a high combustion load, the amount of air supplied from the external air supply pipe, which of these external air supply pipes is closest to the specified atomizer, is increased. liva, or alternatively reduce the intensity of its twist. 47. A device for burning fuel, comprising a combustion chamber having a wall surface equipped with a plurality of solid fuel burners according to claim 31. 48. A device for burning fuel, comprising a combustion chamber having a wall surface equipped with a plurality of solid fuel burners according to claim 31, and a superheater provided in said combustion chamber for boiling water to generate water vapor by using a flame, obtained by using the heat of combustion obtained by burning solid fuel in the specified combustion chamber. 49. A coal-fired boiler comprising a combustion chamber having a wall surface equipped with a plurality of solid fuel burners according to claim 31, and a superheater provided in said combustion chamber for boiling water to generate water vapor by using a flame torch obtained by using the heat of combustion obtained by burning solid fuel in the specified combustion chamber. 50. The method of controlling a device for burning fuel according to clause 47, in which at a high load of combustion in the specified device for burning fuel, a flame of solid fuel is formed, starting from a position far from the specified burner operating on solid fuel, in which at low the burning load in the specified device for burning fuel, a flame of fuel is formed, starting from a position close to the surface of the wall of the combustion chamber directly below the process chain from the exit of the spray A fuel of said burner operated with solid fuels. 51. The method of controlling a device for burning fuel according to claim 50, wherein thermometers or flame-temperature detectors are provided in said solid fuel burners or on the surface of the combustion chamber wall near said solid fuel burners, so that said solid fuel burners control the amount of air ejected from said additional ventilation openings or additional air supply tubes in response to a signal from these measurement points PSI. 52. The method of controlling a device for burning fuel according to claim 50, wherein, at a high load of said device for burning fuel, combustion is carried out in a position that is 0.5 m or more away from the fuel atomizer exit on the central axis of the fuel atomizer in the combustion chamber, in which, at a low load of said fuel burning device, starting from a position located near the surfaces of the walls of the combustion chamber outside the outlet of the fuel atomizer in the combustion chamber, a solid fuel flame is ignited. 53. The method of controlling a device for burning fuel according to claim 50, wherein, at a high load of said device for burning fuel, by using flame temperature detectors or by visual inspection, the torch is monitored in the middle of the combustion chamber where torches of solid fuel burners are merged operating on solid fuel, while at a low load the specified device for burning fuel carry out the current control of a separate torch formed near the exit of each mountain ki, solid fuel. 54. The method for controlling a fuel burning device according to claim 50, wherein, at a low load of said fuel burning device, the amount of air is controlled so that the ratio of the total amount of air supplied by said solid fuel burner to the amount of air needed to fully combustion of volatile substances in fuel was maintained at the level of 0.85-0.95. 55. A coal-fired power plant, comprising a combustion chamber having wall surfaces of the combustion chamber, equipped with a plurality of solid fuel burners according to claim 31, a boiler for boiling water to generate water vapor by using the heat of combustion generated by burning solid fuel by means of said burners, a steam turbine driven by means of water vapor generated by said boiler and an electric generator driven by said steam turbine. Priority on points: 01/29/2001 - according to claims 1 - 30; 08/04/2000 and 05/17/2001 - according to pp.31-41; 08/04/2000 - according to PP.42 - 44, 46; 05/17/2001 - according to paragraphs 45, 47 - 55.

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