RU2279606C2 - Fuel distributor for fuel supply pipe and method of boiler operation - Google Patents

Abstract

FIELD: power engineering.

SUBSTANCE: fuel distributor comprises pipe for supplying fuel that supplies mixed fluid composed of solid fuel and gas to one or more burners arranged over the walls or corner sections defined by the furnace walls, a number of branching pipes originated from the branching section defined inside the pipe for supplying fuel and connected with the burners, and gate mounted inside the pipe for supplying fuel upstream of the branching section. The inclination of the gate with respect to the direction of the flow of the mixed fluid can be changed. The axle of rotation of the gate is mounted at the end section of the gate or at the central part of the gate. The axle is mounted in the central section of the pipe for supplying fuel. The angle of inclination of the gate with respect to the direction of the mixed fluid ranges within ±40°. The distributor is provided with rotating impeller that causes the mixed fluid to flow and is mounted in the pipe for supplying fuel upstream of the gate. The pipe for supplying fuel is mounted for permitting the mixed fluid to flow vertically and is provided with the first pipe for supplying fuel that receives the gate and the second pipe for supplying fuel mounted upstream of the first pipe for supplying fuel and connected with the first pipe. The second pipe is bent in the direction of flow of the mixed fluid. The third pipe for supplying fuel that causes the mixed fluid to flow vertically is connected upstream of the second pipe.

EFFECT: enhanced combustion completeness.

10 cl, 29 dwg

Description

FIELD OF THE INVENTION

This invention relates to a fuel distributor for a fuel supply pipe, a fuel supply system provided with the aforementioned fuel distributor, and a combustion system provided with the aforementioned fuel supply system, and in particular, to a fuel distributor for a fuel supply pipe, which is advantageously installed to improve combustion performance brown coal boiler.

State of the art

On Fig shows an example of a known system for burning brown coal for a boiler. The brown coal combustion system and the boiler design include a coal hopper 1, a mill 3 that atomizes the coal fed from said hopper 1, a fuel supply pipe 4 that delivers mixed fluid formed from coal particles fed from said mill 3 , and a carrier gas for coal particles (here and below, coal particles can be referred to as “pulverized coal”, and a mixture of coal particles and a carrier gas of coal particles can be referred to as “mixed fluid” or “two-phase solid-gas flow "), g rods 5, which are connected to the end parts of said fuel supply pipe 4, a furnace 8 having burners 5 mounted on its side walls, and an exhaust gas pipe 6 that connects a passage in the wall of the furnace 8 with a mill 3 for using coal exhaust gas particles burned in said burners 5 as a carrier gas of coal particles, and a heat exchanger pipe 9, which is installed inside said furnace 8.

Lump coal A is cut in a feeder 2 mounted on the lower part of the hopper 1 and continuously fed to the mill 3. Although a wing mill 3 is used in many cases, the design of the mill 3 is not limited to the wing mill.

In mill 3, coal is dried by high-temperature exhaust gas B, the oxygen concentration of which is less than 21%, and is introduced from the furnace 8 through the exhaust gas pipe 6, while being sprayed at the same time. Mixed fluid C of coal particles (atomized coal) obtained by spraying coal in the form of granules and the exhaust gas is fed through a pipe 4 for supplying fuel to burners 5, which are installed at a plurality of steps in the vertical direction of the side walls of furnace 8. Coal particles fed to burners 5 are burned inside the furnace 8, thereby forming a flame, and the resulting radiant heat is heat absorbed by the heat exchanger pipe 9 mounted on the side walls of the furnace in the upper part of the furnace, and steam is generated.

From the fuel supply pipe 4, the mixed fluid C is distributed over a plurality of burner stages 5 mounted on the side walls of the furnace 8, and in many cases, the burners 5 are installed in (2-4) stages. So, in many cases, these burners 5 many stages are installed in the vertical direction of the side walls of the furnace 8 for each mill 3 (can be installed many mills for each boiler). This is explained by the fact that the pressure productivity at the exit of the vane mill 3 is lower than that of a conventional centrifugal type turbo-blower, etc. That is, the pressure loss on the fuel supply pipe 4 should be limited, and in order to simplify the design of the fuel supply pipe 4, and also to give it an appropriate length not exceeding the required length, it will be advisable to install the group of burners in the vertical direction, and not in horizontal direction.

Moreover, an example of a method of burning in the furnace 8 of the boiler shown in FIG. 20 will be described.

Although, for example, when the load of the boiler is low, the amount of coal A supplied to the burners 5 is reduced, the flow rate of the carrier gas of the coal particles (boiler exhaust gas) in the fuel supply pipe 4 is kept at a fixed flow rate so that the flow rate is not will fall below the minimum flow rate necessary for the stable transfer of coal particles, so as to feed the coal particles obtained by atomizing coal A by mill 3 in a stable mode from mill 3 to burners 5. Thus, when the boiler load is low, the concentration of coal particles in the mixed fluid C supplied to the burners 5 becomes low, and the ignition characteristics of the fuel on the burners 5 may be unstable.

As a countermeasure, part of the set of mills 3 is temporarily stopped (reduce the number of working mills, for example, the number of working mills is changed from four plants to two plants), and at the same time, the concentration of coal particles (atomized coal) in the mixed fluid supplied to the burner 5 each stage, change accordingly.

Known technical solutions shown in Figs. 27, 28 and 29 are solutions for thickening fuel in a pipe 4 for supplying fuel that transfers coal to burners 5. In these known technical solutions for thickening fuel, the concentrations of coal particles fed to respective burners are controlled on the side of the upper stage and the side of the lower stage.

In the example shown in FIG. 27, a main pipe 4 of large diameter 4 for supplying fuel (main pipe) mounted on the upstream side of the flow path of the mixed fluid C, a small diameter pipe 102 for supplying fuel (branch pipe) on the side is used downstream, and this fuel supply pipe 102 (branch pipe) is introduced, thereby branching the flow path of the mixed fluid C into two pipes, with the lower stage burner 501 and the upper stage burner 502 being connected to the end portions their pipes. In the construction shown in FIG. 27, a conical reflector 105 is installed in the inner part of the large diameter main pipe 4 on the side upstream of the main passage of the small diameter branch pipe 102, and the inertia of the coal particles is used to cause the coal particles to accumulate in the direction to the inner wall of the pipe 4 of large diameter, thereby increasing the concentration of coal particles fed to the lower stage burner 501, relative to the concentration of coal particles fed to the upper stage burner 502.

In the example shown in FIG. 28, the fuel supply pipe 4 (main pipe) branches into three pipes, the upper stage burner 503, the middle stage burner 504 and the lower stage burner 505 are installed at the ends of the branch pipes 107, 108 and 109, respectively, distributors (dampers) 115-117 are installed inside the three branch pipes 107-109, respectively, and the respective flow resistances of the mixed fluid C in the branch pipes 107-109 are controlled by the angles of the shutters 115-117 to control the flow of the mixed fluid.

In the example shown in FIG. 29, the main pipe 4 for supplying fuel received from the mill 3 is connected to the upper stage burner 506 without changing the cross-sectional area, and a branch pipe 121 connected to the lower stage burner 507 is located in the middle. The prior art solutions provide the effect that the concentration of coal particles in the mixed fluid C supplied to the upper stage burner 506 is increased due to the inertia of the coal particles.

The aforementioned known technical solutions shown in FIGS. 27-29 have the disadvantage that with burners 501-507 and fuel supply pipes connected to burners 501-507, it is not possible to control the concentration of coal in the mixed fluid C in the branch pipes connected to the main pipe 4. The shutters 115-117 are installed inside the three branch pipes 107-109, respectively, as shown in FIG. 28, and although the flow resistance of the mixed fluid C, including coal particles and the carrier gas, can be changed inside each branch pipe 107-109, it is not possible to selectively change the concentration of coal particles.

The fuel supply pipe shown in FIGS. 27 and 29 does not have elements for regulating the shutter and the corresponding passage for the flow path, and therefore, the concentration of coal particles in the mixed fluid C inside the branch pipes 102 and 121 connected to the main pipe 4 cannot be changed in a convenient manner in accordance with changes in the loading of the boiler.

The above-mentioned known technical solutions also have the disadvantage that it is difficult to control the distribution of concentrations of coal particles in the fuel supply pipe 4 (main pipe), which supplies the mixed fluid C from the vane mill 3 to the corresponding burner stages 5 in the furnace 8 of the boiler.

On the main pipe 4, close to the outlet part of the vane mill 3, the concentration of coal particles per unit cross-sectional area is not necessarily uniform, and in many cases there is a concentration distribution. This is because the coal particles are introduced into the main pipe 4 by the centrifugal force of the impeller blade 16, which, as shown in FIG. 21, is placed inside the impeller mill 3 and rotates at high speed. 21 shows the state of the coal flow in the vane mill 3, and the coal fed to the vane mill 3 is sprayed onto small particles as a result of impact with the impeller blade 16, and the coal particles are pushed to the side of the inner wall of the casing 17 of the vane mill 3 by centrifugal force arising as a result of rotation of the impeller blade 16. This results in a shift in the concentration of coal particles of the mixed fluid, which includes a two-phase flow of solids - gas, on the main pipe 4 near the outlet part of the vane mill 3, and a stream d with a high concentration of coal particles and a stream d ′ s are formed low concentration of coal particles in the direction of the cross section of the main pipe 4 (this displacement below can be called as "displacement of the two-phase flow of solids - gas").

The centrifugal force of the impeller blade 16 is determined mainly by the installation position of the wing mill 3, the design of the pipe 4 for supplying fuel, etc., and it will be difficult to establish the distribution of the concentration of coal particles in accordance with the differences in the designs of the wing mill 3 and burners 5 before the operation of the combustion system coal.

So, in the case where the sorter 18, such as shown in Fig. 22, is installed in the main pipe 4 at the outlet of the vane mill 3, in order to ensure the small size of the coal particles supplied to the burners 5 of the furnace 8 of the boiler, the aforementioned bi-phase flow of solids - gas increases inside the main pipe 4 connected to the part downstream of the sorter 18. This phenomenon will not be described using Fig.22.

The two-phase flows d and d ′ of solids - gas, which were transferred from the vane mill 3 through the main pipe 4 on the side upstream of the sorter 18, collide with a diffusion plate mounted on the sorter, and then coarse coal particles f fall in the direction of entry of the vane mill 3 and return to the inlet of the vane mill not shown through the pipe 20. Incidentally, small coal particles are fed to the corresponding steps of the burner of the furnace 8 through the main pipe 4 on the side of the sorter 18, which is lower on p current. In this process, small coal particles inside the main pipe 4 are moved by flow due to inertia in the direction of the wall of the main pipe 4, closer to the inner wall of the sorter body 19, located opposite the inner wall of the casing 19 on the side on which the diffuser plate 21 of the sorter 18 is mounted, and thus significant heterogeneity is formed in the distribution of the concentration of coal particles in the direction of the cross section of the main pipe 4.

If the mixed fluid C is supplied to each of the branch pipes branching from the main pipe 4, with the aforementioned heterogeneity in the distribution of the concentration of coal particles remaining, then coal particle fuel of an appropriate concentration may not be supplied to each burner 5. For example, the mixed fluid C with low concentration of coal particles can be fed to the burner 5, which must be filed mixed fluid With a high concentration of coal particles. Especially in the case when the boiler must operate at low load, and if the mixed fluid with a low concentration of coal particles is fed to the burner 5, which must be mixed with a fluid medium C with a high concentration of coal particles, the state of combustion of the flame may be unstable and cause a flash of flame.

When the boiler is to operate at low load, the load of the mill must be reduced, and although the amount of coal supplied is reduced accordingly, the flow rate of the carrier gas of the coal particles cannot be reduced below a predetermined flow rate (minimum flow rate) for a steady supply of coal particles. Thus, in order to prevent a flame outbreak, the concentration of coal particles in the mixed fluid C, which must be supplied to a specific burner from burners placed at many stages in the furnace, should be increased to ensure the stability of ignition and stable combustion of the flame on the burner 5.

Moreover, in the case where brown coal or other coal containing a large amount of water or ash is used as fuel for the boiler, the range of concentration of coal particles over which a stable burner flame can be maintained is determined in accordance with the proportion of water or ash contained in corner during the actual operation of the boiler.

So, the stability of the flame of the burner 5 is highly dependent on the concentration of coal particles, the concentration of water and the concentration of ash supplied to the burner 5, and it is known from experience that the stability of the flame of the burner is higher, the higher the concentration of coal particles, the lower the concentration of water and ash concentration. Since coal, such as lignite, contains a large amount of water or ash, ensuring the stability of the burner flame will be important when lignite is used as fuel.

23 and FIG. 26 show an example of reducing the number of mills (from four plants to two plants) for operating the furnace 8 at low load, equipped with burners 5 in the corner parts of the opposite walls. FIG. 26 shows burner flame conditions when a charge is even lower than a charge in the case of FIG. 23. When the number of mills for operating the boiler at low load is reduced and when the heat load inside the furnace 8 is reduced, a stable, high-temperature combustion zone will not be formed in the central part of the furnace 8, as shown in Fig. 23 and Fig. 26, and a method for achieving a stable combustion by means of a self-adjusting flame on each burner. In this case, if the concentration of coal particles is not properly regulated, the burning of coal becomes unstable, and it will be difficult to achieve stable operation of the boiler.

In general, with a low boiler load, the concentration of coal particles fed to the burners of specific stages from the total number of burner stages located in the vertical direction of the side wall of the furnace increases, and this increase in concentration is aimed at stabilizing the burning of the flame of the burner at these specific stages and at the burning stability of the furnace generally. However, even in the case of high values of the condensed coal particles supplied to the burners of specific stages, and with improved stability of the ignition of the burners, the temperature of the exhaust gas at the outlet of the furnace decreases due to the relationship between the heat absorption of the furnace walls in the direction along the height of the furnace and because of the distribution of the flame temperature inside the furnace, thereby preventing a predetermined steam temperature from being obtained. For the stability of the ignition of coal and to achieve the temperature of the exhaust gas at the outlet of the furnace at a predetermined temperature level, it becomes important to control the concentration of coal particles fed to the corresponding burners 5 located on the upper and lower stages.

The aim of this invention is to develop a fuel distributor for a fuel supply pipe by which solid fuel can be supplied to the burner so that ignition stability and stable burning of the ignited flame can be achieved even when the boiler load is low, as well as the development of a feed system a fuel equipped with the aforementioned fuel dispenser for a fuel supply pipe; a fuel combustion device provided with the aforementioned fuel supply system.

Another objective of this invention is the development of a fuel distributor for a fuel supply pipe, which is given the function of reflecting high concentration of solid fuel in a mixed fluid consisting of solid fuel and a carrier gas in a given direction, a fuel supply system equipped with the aforementioned fuel distributor for fuel supply pipes, and fuel combustion devices provided with the aforementioned fuel supply system.

In general, during operation of the boiler at full charge (100% charge), an example of which is shown in FIG. 20, the temperature of the gas leaving the furnace of the boiler is set so that after the gas is heat absorbed by the walls of the heat exchanger, which are installed along the gas flow path on the side downstream of the outlet of the furnace 8, and a heat exchanger pipe 9 installed inside the aforementioned gas flow path, and reaches the rear part of the furnace heat exchanger not shown, the gas temperature will be below the melting point Oles contained in the gas. The temperature of the gas leaving the boiler’s furnace when the boiler is fully loaded is also set so that the temperature of the metal surface not shown in the drawings of the heat exchanger pipe installed on the rear part of the heat exchanger does not increase sharply to or above the surface heat resistance temperature.

However, when the boiler switches from full load to partial load, since the amount of heat entering the furnace decreases, the temperature of the gas at the outlet of the boiler decreases, and the temperature of the steam at the exit of the boiler drops below the temperature of the steam required at the turbine inlet on the consumed side steam (this temperature can be called "the temperature of the steam required on the side of the consumed steam").

Thus, it is another object of the invention to provide a fuel dispenser for a fuel supply pipe, by which, when a boiler using a mixed fluid consisting of solid fuel and carrier gas is switched from a full load operation mode to a partial load mode, it is prevented a sharp drop in the temperature of the gas at the outlet of the boiler furnace, so that the temperature of the steam at the exit of the boiler will not fall below or equal to the mentioned temperature of the steam required on the side of the consumed steam. The aim of the present invention is also to develop a method of operation of a boiler equipped with the aforementioned fuel distributor for a fuel supply pipe, allowing to raise the concentration of the solid phase for a particular burner from a plurality of burners.

SUMMARY OF THE INVENTION

This invention is directed to the development of a fuel dispenser for a fuel supply pipe, and this pipe delivers a mixed fluid including, in turn, solid fuel and a carrier gas (e.g., burnt exhaust gas or other gas with an oxygen concentration of less than 21%), one or more burners located on the walls or corner parts formed by the walls of the furnace, said fuel distributor includes a plurality of branch pipes that branch from a branching part formed in said fuel supply pipes e, and each of which is connected to a corresponding burner, and a damper that is installed inside the fuel supply pipe on the side upstream of the branching part, and which can be changed in angle with respect to the flow of the mixed fluid so that the mutual difference will be occur in the concentration of solid fuel mixed fluid supplied to the corresponding branch pipes.

The axis of rotation of the shutter for changing the angle of inclination of the aforementioned shutter in the aforementioned fuel distributor for the fuel supply pipe (main pipe) is preferably mounted on the end part of the shutter (see Figure 2) or on the central part of the shutter (see Figure 4), and this axis The rotation of the damper is preferably located in or near the central part of the pipe, in the part that lies upstream of the aforementioned branching part.

In the presence of the aforementioned fuel supply pipe, which is located on the downstream side and has branch pipes that are respectively connected to each of the plurality of burners facing the furnace, the distribution coefficient of the carrier gas of solid fuel in a mixed fluid including the two-phase flow of a solid - gas, can be made constant, and the concentration of solid fuel can be increased in an arbitrary direction by adjusting the angle of inclination of the shutter mounted on the side Chez aforementioned downstream part which is branched to branch off pipes. This is possible because the pressure loss between the damper and the inlets of the corresponding branch pipes is insignificant compared to the total pressure loss from the side upstream of the branching part of the fuel supply pipe, through the branch pipe burners, and to the furnace, and the distribution coefficient can thus , remain constant, and it becomes possible inertial separation of only solid fuel. Particles of solid fuel will be exposed to flow displaced to the selected path (each branch pipe).

In general, a combustion system is used whereby solid fuel particles are fed through a single pipe to supply fuel to a plurality of burners installed on the upper and lower steps of the furnace, and if the angle of inclination of the shutter is adjusted so that a larger amount of the above mixed fluid including solid phase and gas phase will flow to the branch pipe of a particular burner from a plurality of burners, although the solid phase and gas phase will tend to keep the aforementioned ca. due to inertia force even after the passage of the portion where the damper is installed, the gas phase having a low density and thus small inertia, loses its inertia rapidly and the flow will tend to uniform flow of branch pipes which are connected to the respective burners. Incidentally, in the presence of a solid phase having a high density, the aforementioned biased flow is established faster due to the large inertia. The inhomogeneous distribution of the concentration of solid fuel along the corresponding branch pipes (characteristics of the inhomogeneous distribution) will thus be preserved.

According to the above principle, most of the solid phase will have to selectively flow to a branch pipe connected to a particular burner. This can be called a type of inertial sorting (classification), and this type of sorting will be attributed to inertial sorting, which is asymmetric with respect to the direction of flow (direction of the main axis) of the two-phase flow of solids - gas in the fuel supply pipe (main pipe) to distinguish it from the distribution method described below.

In order for the coal to spontaneously ignite on the burner, it is necessary to supply heat (the calorific value of the supplied coal), the concentration of coal and oxygen in excess of or equal to fixed values. However, due to the use of exhaust gas from a boiler with a low oxygen concentration as a carrier gas of coal particles (atomized coal), the carrier gas that is supplied to the mill, and due to the water vapor generated by drying the coal in the mill and added to mixed fluid supplied to the burner mixed fluid will have a significantly reduced oxygen concentration (reduced to 15%).

Thus, when the mixed fluid is distributed over a plurality of burners from the same mill through the fuel supply pipe, the characteristic of spontaneous combustion of the fuel on a particular burner can be maintained while providing the minimum required amount of heat input and coal concentration. The flame can thus be generated and stored on at least one burner per mill in the furnace.

In the case of using brown coal, which has a low calorific value and a high water content, it will be important to raise the solid phase concentration for a particular burner from a plurality of burners to which brown coal is supplied from the same mill as solid fuel. By fulfilling this requirement, it is possible to avoid a flash of flame on said specific burner even in the case where the load is low for a furnace using brown coal as fuel.

A device is also used in the present invention in which, preferably, the following ratio is maintained for a distance L from the aforementioned axis of rotation of the shutter to the aforementioned branch portion in the direction of flow of the mixed fluid and for the diameter D of the fuel supply pipe (see FIG. 7):

L / D = 0.4-2.

In general, a combustion system is used that uses solid fuel particles supplied through a fuel feed pipe to a plurality of burners installed on the upper and lower steps of the furnace, and if the aforementioned L / D ratio is outside the aforementioned range, then the solid fuel-coal concentration coefficient fed to a specific burner becomes low.

If the aforementioned L / D ratio is less than 0.4, then the concentration ratio of the solid fuel to a particular burner becomes low, and a flame may occur on this burner when low loading operation is performed, in which the amount of fuel supplied to the furnace is reduced overall. When the L / D ratio is greater than 2, the distance between the shutter and the branching part of the pipe will be too large, and there will be a phenomenon in which solid particles of high concentration fuel that have been distributed for supply to a particular burner are again uniformly distributed in the supply pipe fuel, thereby preventing the accumulation of solid fuel with a high concentration in the direction of the above-mentioned specific burner. Thus, in order to maintain a high concentration coefficient of solid fuel particles in the direction of a specific burner from burners installed in many stages, the distance L between the upper end of the valve and the branching part of the pipe is preferably set (0.4-2) times larger than the diameter D pipes for supplying fuel.

Thus, the device will be preferable in which the angle of inclination of the aforementioned damper relative to the direction of flow of the mixed fluid can be changed within a range of ± 40 °.

If the aforementioned angle of inclination of the shutter is equal to or more than 30 °, then the concentration coefficient of coal particles towards the specific burner from the burners of the upper and lower stages becomes saturated, and the pressure loss on the parts where the shutter, pipes for supplying fuel increases. The aforementioned angle of inclination of the shutter is thus set preferably in the range of about ± 30 °, and in practice the maximum angle of inclination is chosen adjustable within the range of 40 °.

A rotating turntable for mixing the mixed fluid stream may be installed in the above-described fuel supply pipe on the upstream side of the above-described shutter (see FIG. 15). In this case, strong mechanical rotation can be applied to the two-phase flow of solids - gas by means of a rotating pinwheel in the fuel supply pipe, and thus, even if there is a displaced stream in the fuel supply pipe on the side upstream of the rotating pinwheel, the displaced stream can be forcedly adjusted by means of a rotating turntable.

The aforementioned fuel supply pipe in the fuel distributor for the fuel supply pipe according to this invention is arranged so that the mixed fluid flows in a vertical direction, and said pipe can have a device having a first fuel supply pipe 4a in which the above-described shutter is installed and a second fuel supply a pipe 4b mounted on the upstream side of the first fuel supply pipe 4a and bently connected to the first fuel supply pipe 4a (see FIG. 10 and FIG. 14).

Here, the aforementioned fuel supply pipe 4b is preferably bent in a direction in which the mixed fluid will be oriented to increase the differential concentration of solid fuel in the mixed fluid supplied to the respective burner pipes caused by the aforementioned damper.

If the fuel supply pipe has the aforementioned bent-connected part (elbows E and E ′ of FIG. 10 and FIG. 14), then the bent-connected part is designed to create a biased flow, in particular for the solid phase of a two-phase solid-gas flow. By setting the directivity of this biased flow to match the direction of the biased flow, which is asymmetric with respect to the axis of the inertial type flap, the characteristic of the inhomogeneous distribution (displacement of the solid phase or concentration of the solid phase towards a certain area) of the fuel supply pipe on the downstream side of the part where a shutter is installed, and the charcoal particle distribution characteristic of the shutter of this invention will not be ruled out by biased two-phase sweat with an eye of solids - gas in the pipe for supplying fuel on the side upstream.

So, the third fuel supply pipe 4c, which causes the mixed fluid to flow in the vertical direction, can be connected on the upstream side of the above-described second fuel supply pipe 4b.

In this case, the first fuel supply pipe 4a, the second fuel supply pipe 4b, and the third fuel supply pipe 4c form elbows E and E ′ at two locations, that is, at the upper location and lower location in the entire fuel supply pipe (FIG. 14). Thus, an offset O is set between the main axes of the first fuel supply pipe 4a and the third fuel supply pipe 4c, which are arranged in the vertical direction. Due to this displacement O, the mixed fluid passing through the third fuel supply pipe 4c collides with the upper part of the wall of the second fuel supply pipe 4b, while the direction of the mixed fluid flow, including the two-phase flow of solids - gas, changes, and after reaching the damper to the first fuel supply pipe 4a, the flow direction changes in the opposite direction. The result of the displacement of the solid phase flow in the mixed fluid can thus be achieved with a low pressure loss, and a large amount of coal particles can be forced to flow at a higher concentration to a branch pipe connected to a particular burner.

Together with the fuel distributor for the fuel supply pipe according to this invention, a restrictor can be installed that restricts the flow of mixed fluid in the fuel supply pipe on the upstream side of the shutter (see FIG. 16 and FIG. 17).

When the aforementioned restrictor is installed in the fuel supply pipe, the mixed fluid stream, including a two-phase flow of solids - gas, first narrows towards the main axis of the fuel supply pipe, and then diverges after passing through the limiter. The distribution of the concentration of coal particles in the direction of the cross section of the fuel supply pipe becomes thus uniform immediately after passing through the restrictor and beyond, and a mixed fluid having a high concentration of coal particles on the side of a particular burner pipe is forced to flow through a shutter.

Thus, even in the case when a biased flow is generated in the fuel supply pipe, such as a two-phase solid-gas flow, having a high concentration of solids in the direction of the branch pipe for a particular burner, for which the concentration of solids should not be high, since this displaced flow lies on the side upstream of the restrictor, it will not be possible to raise the concentration of solid particles in a two-phase flow of solids - gas supplied to a particular burner.

So, by installing the aforementioned restrictor with a device that allows you to change the degree of restriction to increase the differential in the concentration of solid fuel mixed fluid supplied to the corresponding branch pipes, due to the aforementioned damper, the concentration of solid particles passing through a particular branch pipe from a variety of branch pipes can be quickly increase or, otherwise, adjust.

The invention is also directed to a fuel supply system in which the above-described fuel distributor for a fuel supply pipe is installed between a solid fuel atomizing mill and corresponding burners mounted on the walls of the furnace, and the invention is also directed to a solid fuel combustion system equipped with the aforementioned fuel supply system.

In the fuel distributor of the present invention, a branch pipe damper is provided for the fuel supply pipe by which the passage area of the branch pipe can be changed when the shutter is moved from a fully open state to a fully closed state, and this shutter can be installed inside at least one branch pipe connected to a particular burner of a plurality of burners arranged in the height direction of the walls of the furnace or the corner parts formed by the walls (see FIG. 24 and FIG. 25).

The method of operation described below can be used in a solid fuel boiler equipped with the fuel supply system described above having a fuel distributor in which a shutter is installed inside a branch pipe.

That is, this method of operation is a method of operating a solid fuel boiler, in which coal particles atomized by a single coal atomizing mill for crushing coal are supplied together with a carrier gas through a fuel supply pipe and through a plurality of branch pipes branching from the aforementioned pipes for supplying fuel to each of the burners corresponding to the pipes of the burners and arranged at a plurality of steps in the direction of the height of the walls of the furnace or the corner sections formed by the walls of the furnace. And with this method of operation of the boiler for burning fuel, it is provided to use a shutter installed inside the pipe for supplying fuel on the side upstream of the aforementioned branch pipes and having a variable angle of inclination relative to the direction of flow of the fluid, consisting of solid fuel and carrier gas, and the use of another damper, which can be used to change the passage area of the branch pipe from a fully open state to a fully closed state, with another damper installed at least inside one branch pipe of a plurality of branch pipes connected to the burner in the lower stage, the damper is adjustable in the branch pipe connected to the burner of the lower stage. The aforementioned flap of the fuel supply pipe is adjustable. Another damper in the branch pipe connected to the lower stage burner works in the open direction to feed the coal particles in a condensed form when the boiler starts up, and when the load changes after the stabilization of combustion, the load changes from a high value to a low value, while said damper in a branch pipe connected to a low stage burner operates in the closing direction.

By adjusting the damper of the pipe for supplying fuel and feeding the coal particles in a condensed form into a branch pipe connected to a low-stage burner, during the start-up of the boiler, fuel combustion can be provided on the lower-stage burner during the start-up of the boiler, in which the fuel is burned is unstable.

So, when the aforementioned valve is operated in a branch pipe connected to the lower stage burner in the closing direction, when the boiler switches to the low load mode after the high load operation mode, in which stable combustion of the fuel is achieved, the gas temperature at the furnace outlet can become adequately high to ensure the temperature of the steam required on the consumption side, and to prevent problems that arise due to a decrease in the temperature of the steam.

Brief Description of the Drawings

Figure 1 is a view in longitudinal section of a pipe for supplying fuel of the first embodiment of this invention.

Figure 2 is a detailed view in longitudinal section of a pipe for supplying fuel according to Figure 1.

Figure 3 is a plan view of a shutter used in the fuel supply pipe of Figure 1.

4 is a detailed longitudinal sectional view of a fuel supply pipe of a second embodiment of this invention.

FIG. 5 is a plan view of a shutter used in the fuel supply pipe of FIG. 4.

6 is a diagram that illustrates a characteristic of the distribution of coal particles to the lower stage burner of the first embodiment of the invention and the second embodiment of this invention.

7 is a diagram that illustrates a characteristic of the distribution of coal particles to the lower stage burner of the first embodiment of the invention and the second embodiment of this invention.

Fig. 8 is a diagram that illustrates a distribution characteristic of coal particles to a lower stage burner of a first embodiment of the invention and a second embodiment of this invention.

Fig.9 is a view in longitudinal section of a pipe for supplying fuel of the third embodiment of this invention.

Figure 10 is a view in longitudinal section of a pipe for supplying fuel of the fourth embodiment of this invention.

11 is a diagram that explains a method for increasing a deviation of a coal flow in a fuel supply pipe of a fourth embodiment of this invention.

12 is a diagram that explains a method for increasing a deviation of a coal flow in a fuel supply pipe of a first embodiment of this invention.

13 is a diagram that explains the phenomena of increasing coal flow and reducing pressure loss on the lower stage burner in cases where pipes for supplying fuel of the first and fourth embodiments of the invention are used.

FIG. 14 is a longitudinal sectional view of a fuel supply pipe of a fifth embodiment of this invention. FIG.

15 is a longitudinal sectional view of a fuel supply pipe of a sixth embodiment of this invention.

FIG. 16 is a longitudinal sectional view of a fuel supply pipe of a seventh embodiment of this invention. FIG.

17 is a longitudinal sectional view of a fuel supply pipe of an eighth embodiment of this invention.

Fig. 18 is a diagram that illustrates a distribution characteristic of coal particles on a burner of a lower stage of a seventh embodiment and a first embodiment of this invention.

FIG. 19 is a longitudinal sectional view of a fuel supply pipe explaining a problem that may arise in a first embodiment of this invention. FIG.

Fig. 20 is an explanatory diagram of a fuel supply system for a brown coal boiler.

Fig is a diagram that shows the state of the flow of coal in the vane mill shown in Fig.20.

Fig.22 is a partial view in longitudinal section of a sorter, illustrating the state of the coal flow in the case when the sorter is installed in the pipe for supplying fuel, shown in Fig.20.

FIG. 23 is a horizontal sectional view of the inside of the furnace during sustained combustion when the load is low.

24 is a longitudinal sectional view of a fuel supply pipe of a ninth embodiment of this invention.

25 is a longitudinal sectional view of a fuel supply pipe of a tenth embodiment of this invention.

Fig. 26 is a horizontal sectional view of the interior of the prior art furnace during unstable combustion when the load is low.

Fig. 27 is a horizontal sectional view of a prior art fuel supply pipe.

Fig. 28 is a horizontal sectional view of a prior art fuel supply pipe.

Fig.29 is a view in horizontal section of a pipe for supplying fuel of the prior art.

The best modes for implementing the invention

Embodiments of this invention will be described with reference to the accompanying drawings. The embodiments described below relate to a fuel supply pipe 4, which extends vertically and which uses the furnace exhaust gas as a carrier gas to supply brown coal sprayed by a wing mill 3, to the burners 5 of the furnace 8 of the brown coal boiler, as shown on Fig. The aforementioned burners 5 are mounted on a plurality of steps in the vertical direction of the side walls of the furnace 8, and the fuel is supplied by the wing mill 3 to the respective burners 5, as well as through the fuel supply pipe 4, as will be described below. The fuel supply system for burners 5 of these embodiments of the invention, described below and provided with a fuel supply pipe 4, in which the concentration distribution and distribution of the flow of coal particles in the fuel supply pipe 4 on the upstream side of the shutter component of the fuel supply system can be adjusted so as to make the concentration of coal particles flowing through the branch pipe 4 connected to the burner 5 of the lower stage of the furnace 8 of the boiler higher than the concentration of coal particles ekayuschih through branching pipe 4 connected to a higher stage burner 5. Although examples in which the fuel supply pipe 4 branches into two pipes connected to the upper stage burner and the lower stage burner, respectively, are illustrated by the embodiments of the invention described below, the fuel supply pipe 4 of this invention is not limited to such a two-branch design.

First incarnation

Figure 1 is a sectional view of the main parts of the fuel supply pipe of this embodiment, and Figure 2 shows a detailed structure around the shutter that is installed in the fuel supply pipe of Figure 1.

The fuel supply pipe system of FIG. 1 consists of a main pipe 4, which extends in a vertical direction, a shutter 11, which is installed on the upstream side inside the main pipe 4 near the branch point 14 of the pipe, and branch pipes 15 and 16 formed in the result of branching and connected to the burner 12 of the upper stage and the burner 13 of the lower stage, respectively.

The axis of rotation 11a of the valve 11 is located in the direction of intersection of the main pipe 4 near the Central part of the main pipe 4, as shown in Fig.2.

As shown in FIG. 2, the rotation axis 11a of the shutter is mounted on the upper end part of the shutter 11 in this embodiment. As shown in a plan view of the shutter 11 of FIG. 3, the shutter 11 has a substantially semicircular shape, and an axis of rotation 11a of the shutter is provided on a straight portion at the upper end of the shutter 11.

The damper 11 has a device in which when the axis of rotation of the damper 11a is rotated, the inclination angle θ of the damper 11 with respect to the vertical line (hereinafter simply referred to simply as “the inclination angle of the damper 11”) is set to an appropriate value, and the damper 11 can be held there position.

Second incarnation

FIG. 4 is a longitudinal sectional view of the main parts of the fuel supply pipe of this embodiment, which is an embodiment of the first embodiment, and FIG. 5 is a plan view of the shutter of FIG. 4. The damper 11 has a round shape, which coincides with the cross-sectional shape of the main pipe 4.

The damper 11 can also be held in this case at an appropriate angle of inclination e ′ during rotation of the axis of rotation 11a of the damper.

6 shows the relationship between the coal concentration coefficient towards the lower stage burner 13 in the first embodiment and the second embodiment and the value (L1 / LD), which is the ratio of the length (L1) from the upper end of the shutter 11 to the pivot axis 11a to the maximum width (LD) damper. The coal concentration coefficient towards the lower stage burner 13 is the ratio of the concentration of coal fed to the branch pipe 16 on the side of the lower stage burner to the concentration of coal in the mixed fluid in the main pipe 4.

As indicated by (L1 / LD), when the inclination angle θ of the shutter 11 with respect to the direction in which the mixed fluid flows through the main pipe 4 (vertical direction) is 30 °, then the mixed fluid C with the highest concentration of coal can be reached towards the burner 13 of the lower stage when L1 = 0 is long (first embodiment).

So, when (L1 / LD) = 0.4 or higher, although the distribution will remain almost constant, the pressure loss on the shutter 11 becomes high. Since the productivity of the pressure at the outlet of the vane mill 3 (Figure 1) is low, compared with a conventional centrifugal type turbofan, etc., the pressure loss inside the branch pipes 15 and 16 branching from the main pipe 4 should be limited to low level.

From the foregoing, it can be understood that, in the presence of the devices of the first and second embodiments, the position of the damper rotation axis 11a is preferably set within the range from the upper end of the damper to a point lying at half the maximum width (LD) of the damper 11.

Fig. 7 shows the results of checking the relationship between the installation position of the shutter 11 and the concentration coefficient of coal particles towards the burner 13 of the lower stage when the inclination angle θ of the shutter 11 is set to 30 ° for the second embodiment shown in Fig. 4.

Here, the ratio of the concentration coefficient of coal particles towards the burner 13 of the lower stage was checked, which was determined based on the ratio of the distance L between the upper end of the shutter and the branch point 14 and the diameter D of the main pipe 4.

When the distance L is small compared to the diameter D of the shutter 11, that is, when the L / D becomes lower than 0.4, the concentration coefficient of the carbon particles towards the burner 13 of the lower stage becomes low. This is because the flow resistance of the mixed fluid exerted by the shutter 11 increases, and since the amount of gas flowing into the branch pipe 16 connected to the burner 13 of the lower stage (the burner for which coal is thickened to improve the ignition performance) also increases , the concentration of carbon particles within the aforementioned branch pipe 16 does not increase to the same extent. On the other hand, when L / D exceeds 2.0, the coal particles directed to the branch pipe 16, on the side of the burner 13 of the lower stage, are re-scattered inside the main pipe 4 before reaching the branch pipe 16, and the concentration coefficient of the coal particles in the direction toward the burner 13 of the lower stage is thus reduced. Therefore, to increase the concentration coefficient of coal particles towards the lower stage burner 13, the distance L between the upper end of the shutter and the branch point 14 is preferably set (0.4-2) times larger than the diameter D of the fuel supply pipe.

The only operation in which the concentration coefficients of coal particles from the main pipe 4 towards the burner 12 of the upper stage and the burner 13 of the lower stage can be adjusted during the working test of the boiler is the operation of adjusting the angle θ of the shutter 11. Fig. 8 shows the results checking the ratio of the angle θ of the inclination of the shutter 11 and the concentration coefficient of coal particles in the direction of the burner 13 of the lower stage. It becomes apparent that when the angle of inclination θ of the damper is equal to or greater than 30, the aforementioned distribution coefficient saturates and the pressure loss (not shown) on the part of the main pipe 4 on which the damper is mounted increases. If the angle of inclination of the damper is equal to or more than 30 °, although the number of coal particles directed to the branch pipe increases, in which the supplied coal particles must be condensed, it is considered that the concentration coefficient does not change due to the fact that the quantity increases to the same extent gas.

As mentioned above, since the pressure loss of the mixed fluid C inside the branch pipes 15 and 16 must be limited to a low level, the angle of inclination of the damper θ is preferably set to approximately ± 30 ° with respect to the vertical line passing through the axis of rotation 11a of the damper 11 , and in practice, the angle of inclination of the damper is controlled in the range of a maximum of 40 °.

In the above-described cases of the first and second embodiments, the mixed fluid stream C, which is transferred from the vane mill 3 (see FIG. 20), from the boiler exhaust gas, as shown in FIG. 1, is impacted with a shutter 11 installed inside the main pipe 4, held under angle of inclination θ relative to the vertical direction, and becomes a biased flow, while the coal particles, which are solids, flow in the form of a stream of coal particles F, which has a low concentration of coal and flows mainly to the pipe 15, along connected to the burner 12 of the upper stage, and in the form of a stream E of coal particles, which has a high concentration of coal and flows to the pipe 16 connected to the burner 13 of the lower stage, and these flows are thus fed into the furnace 8 of the boiler from the burner 12 of the upper stage and burner 13 lower steps, respectively.

With such an installation of the damper 11 on the side upstream of the branch point 14 of the main pipe 4 and when the axis of rotation of the damper 11a is installed above the central part of the damper, the distribution coefficients of the carrier gas in the mixed fluid C including coal particles and boiler exhaust gas can be made the same for the branch pipes 15 and 16, and the distribution of only solid fuel can be changed in an arbitrary direction (towards the branch pipe 16 in the first and second embodiments of the invention). And this is due to the fact that the flow of solid fuel particles was shifted to the selected path by the action of inertia when installing the shutter 11. Thus, by adjusting the angle of inclination θ of the shutter 11, the concentration of fuel supplied to the burners 12 and 13 of the upper and lower rungs.

Thus, when the boiler is low loaded, the shutter 11 can, for example, be given an angle of inclination such that mixed fluid C with a high concentration of coal particles is fed to the burner 13 on the side of the lower stage of the furnace side wall in order to ensure stable ignition of the coal particles and stable combustion lit flame inside the boiler.

Third incarnation

Figure 9 shows an example of a fuel supply pipe having a rectangular cross-section, in the construction of which branch pipes 15 and 16 branching from the main pipe 4 and connected to the burners 12 and 13 of the upper and lower stages, respectively, are parallel in the upper direction and are separated burners 12 and 13 of the upper and lower stages are nearby from a friend. The damper 11 is installed inside the main pipe 4 in the direction of flow, where the pipe 4 branches to the burner 12 of the upper stage and the burner 13 of the lower stage.

As shown in FIG. 9, the shutter 11 has a device on which its pivot axis 11a is mounted on the upstream side and along a vertical line passing through the branch point 14. And this pivot axis 11a is mounted on a part of the upper end of the shutter 11. Since the shutter 11, as shown in FIG. 9, is turned to the branch pipe 15, which leads to the upper stage burner 12, the concentration of coal particles in the mixed fluid E supplied to the branch pipe 16 leading to the lower stage burner 13 becomes higher than the concentration in the mixed fluid F passing through the branch pipe 15 leading to the upper stage burner 12.

Although the third embodiment provides the same results as the aforementioned first embodiment, it also has the following advantage due to the rectangular cross section of the fuel supply pipe.

That is, with respect to the structure, in this embodiment, restrictors 25 and 26 can be installed (FIG. 17), which can change the cross-sectional area of the flow path, which ensures high responsiveness and almost unlikely local inhomogeneous wear of the structure, since the plates consist only of straight parts etc.

Fourth incarnation

This embodiment corresponds to a device in which a curved second main pipe is connected on the upstream side of the vertically extending main pipe 4, has a valve 11 mounted therein for supplying fuel of the first embodiment described above.

FIG. 10 shows a longitudinal sectional view of the main parts of the fuel supply pipe of this embodiment, and this device is provided with a main pipe 4a having a shutter 11 installed therein, installed in the upstream part in the main pipe 4a near the branch point 14 of the pipe, and branching pipes 15 and 16, which are connected to the upper stage burner not shown in the drawing and to the lower stage burner not shown in the drawing, respectively. The damper 11 is provided with an axis 11a of rotation of the damper, which intersects the main pipe 4a in the vicinity of the central part of the main pipe 4a. The damper 11 is rotatably mounted about an axis 11a and can be held in an inclined position at a corresponding angle θ.

Although, as shown in FIG. 10, the pivot axis 11a is located on the central part of the shutter 11, it can be mounted on a part of the upper end of the shutter 11, as shown in FIG. 2. Similar to the installation position of the pivot axis 11a on the flap shown in FIGS. 14, 15 or 11, the pivot axis 11a can be mounted on a part of the upper end of the flap 11.

Even if, for example, the inclination angle θ of the shutter 11 shown in FIGS. 1-5 is set so that the mixed fluid of a relatively high concentration of coal particles is supplied to the lower stage burner 13, and not to the upper stage burner 12, if the displaced flow solid phase (coal particles), which takes place inside the main pipe 4 on the side upstream of the valve 11, is formed in such a way that a mixed fluid of a relatively high concentration of coal particles will be fed to the burner 12 of the upper stage, and not to the burner 13 of the lower stage, in contrast to what was assumed by setting the angle θ of the shutter 11, the beneficial effect of installing the aforementioned shutter 11 will be lost.

Thus, in the present invention, the characteristic of the flowing solid phase (carbon particles) in the biased flow is improved inside the main pipe 4b on the upstream side of the main pipe 4a in which the shutter 11 is installed to further support the result of the presence of the biased flow of the shutter 11. Mixed fluid a relatively high concentration of coal particles can thus be fed to the lower stage burner communicating via branch pipe 16, and not to the upper stage burner communicating through vetvlyayuschuyusya pipe 15.

The dispenser for the fuel supply pipe of the embodiment shown in FIG. 10 generally consists of four parts. Regarding the construction, this embodiment is characterized in that an elbow E (bent portion) is formed between the main pipe 4a in which the shutter 11 is installed and the main pipe 4b on the upstream side.

The lowest downstream part of the main pipe 4a branches into two parts and is provided with a branch pipe 15 connected to the upper stage burner and a branch pipe 16 connected to the lower stage burner and a shutter 11 with its pivot axis 11a located in front of the branch point 14. The pivot axis 11a is set in the direction of the main pipe 4a.

The position of the shutter 11 can be changed by changing its angle of inclination e relative to the axis of rotation 11a. If the clockwise rotation direction is taken as a positive rotation angle, then when the angle θ is set in the range 0 <θ <90 °, the trajectory of the mixed fluid (two-phase flow of solids - gas) supplied from the upstream side is bent by the shutter 11, and the fluid is forced to flow more to the lower stage burner through the branch pipe 16. That is, the volume of the mixed fluid stream in the branch pipe 16 increases. Since the phase of solids has a higher density and inertia than the gas phase, the growth rate of the flow volume on the pipe 16 will be higher for the phase of solids than for the gas phase. As a result, the volume flow of the phase of solids on the branch pipe 16 increases, and at the same time, the concentration of the phase of solids (the concentration of carbon particles in the mixed fluid) increases on the branch pipe 16.

When setting the angle θ of the inclination of the shutter 11 in the range of -90 ° <θ <0, there will be a phenomenon opposite to the above when setting the angle of inclination θ in the range 0 <θ <90 °, and the volume flow of the solid phase, as well as the concentration of the solid phase increase in the branch pipe 15.

A characteristic feature of the shutter 11 in the distributor for the fuel supply pipe of this embodiment is that since the inertial sorting shutter asymmetric with respect to the axis is deliberately used, the concentration of coal particles in the cross-sectional direction of the main pipe 4a in which the shutter 11 is installed increases substantially monotonously in downstream side of the pipe.

Corresponding vectors in the flow direction (main axis direction) F1 of the mixed fluid in the main pipe 4b on the side upstream of the elbow E, in the direction F2 of the main axis of the main pipe 4a on the downstream side of the elbow E, in the direction F3 of the main axis of the branch inlet pipes 15, which are connected to the burner of the upper stage, and in the direction F4 of the main axis of the input part of the branch pipe 16, which is connected to the burner of the lower stage, are formed in the same plane. The rotational axis 11a of the shutter is set in a direction perpendicular to the aforementioned plane.

In this embodiment of the distributor for the fuel supply pipe, which satisfies the above conditions, when the angle of inclination of the flap θ is set in the positive direction in the range 0 <θ <90 °, the orientation of the main pipe 4b on the upstream side of the part on which the flap 11 is mounted is set at setting the angle a ′ (the clockwise direction is the positive direction for a ′), formed by the direction F1 in the main axis and the direction F2 of the main axis, which should lie in the range 0 <a ′ <180 °, by means of E. E. When this angle a ′ is set in this way, the trajectory of the mixed fluid (two-phase flow of solids - gas) that flows into the main pipe 4a is bent in the negative direction of angle a ′ by the elbow E. Since the solid phase of the coal particles, having a high density, has a high inertia at this point, a displaced flow of mixed fluid takes place, and a mixed fluid that reaches the part on which the shutter 11 is mounted increases further in the aforementioned displaced flow through the valve 11 in such a way that the concentration and volume of the flow of coal particles (solid phase) in the mixed fluid that flows towards the branch pipe 16 increase relative to the volume of the stream and the concentration of the fluid flowing to the branch pipe 15. With this orientation the fuel pipe distributor shown in FIG. 10 can provide a distribution characteristic that is superior to or equivalent to distribution performance due to the presence of a damper 11 for nyh particles (solid phase) in the mixed fluid in the main pipe 4a at the portion where the damper is installed. Thus, the combined effect of the knee E and the damper 11 is ensured.

On the other hand, although, in general, when the inclination angle θ of the shutter 11 is large, the performance of the distribution of coal particles in the mixed fluid increases, since the passage area of the mixed fluid in the pipe 4a narrows, the loss of pressure carrying the fluid and created vane mill 3. Thus, when installing the elbow E in the main pipe 4b on the side upstream of the part where the damper is installed, the performance of the distribution of coal particles (solid phase) can be achieved at an equivalent level the valence level of the embodiments shown in FIGS. 1-5, at a lower fluid-carrying pressure.

Typically, with the system shown in FIG. 20, for supplying coal to the boiler furnace 8, a fuel supply pipe 4 having a wing mill 3 at the highest upstream point is designed to provide the shortest path extending in the vertical direction in order to reduce loss pressure during the transfer of mixed fluid. However, in many cases, the presence of a curved part in a vertical plane cannot be avoided when placing various equipment for the transfer of fluid. When installing an elbow E with an angle of inclination a ′ in the main pipe 4b on the upstream side of the part on which the shutter is installed, as such a bent part, the pressure loss of the fluid transfer system, which again occurs as a result of the aforementioned angle a ′, should not be attributed to pressure loss of the entire mixed fluid transfer system. That is, the pressure loss inevitable on the curved part can be effectively used to improve the distribution characteristics. The distribution characteristic can thus be improved without increasing pressure loss.

So, when the aforementioned tilt angle a ′ is set to about 90 ° (when there is a horizontal part in the part of the main pipe 4b on the upstream side of the part on which the shutter is mounted), the influence of gravity acting on the solid phase in the main pipe 4b affects maximum degree. Since the dense phase of solids will thus tend to quickly form on the bottom of the main pipe 4b, a distribution characteristic involving the separation of the mixed fluid in the distributor as a whole for the pipe supplying fuel to an area with a higher concentration of coal particles (solid phase) and a higher concentration of carrier gas (gas phase) can be improved to the maximum extent. Moreover, when installing a pipe device with the aforementioned curved part, in which the main pipe 4 has an angle of inclination a ′, close to the exit of the vane mill 3, there is no need to install the bent part again in the main pipe 4b on the upper side of the flow side of the part on which the shutter is installed .

The main advantages of this embodiment are shown in FIG. 11. They will be described by comparison with the characteristics of the first embodiment shown in FIG.

The three diagrams that are shown on the right side of the figure are diagrams of the distribution of the volume of coal flow in the cross section a-b in the main pipe 4b, in the cross section cd on the side downstream of the bent portion of the elbow E, and in the cross section ef in front of point 14 branching of the main pipe 4a. The mixed fluid stream, which exhibits a substantially uniform distribution of the flow volume in the cross section a-b in the main pipe 4b, shows an increased value on the right side of the distribution diagram of the coal flow volume over the cross section cd on the side downstream of the bent portion of the elbow E Incidentally, with the device of FIG. 1, a uniform flow distribution is maintained in the same position (FIG. 12). For a given distribution state, the volume of the coal flow is made even more heterogeneous by the shutter 11 in the example shown in FIG. 11, and thus a high value of the distribution of the flow volume in the e-f section in the main pipe 4a on the downstream side of the shutter is obtained. Since this distribution of the volume of the coal stream is directly reflected in the branch pipe 15 and the branch pipe 16, the volume of the coal stream in the branch pipe 16 is significantly increased in the present embodiment compared with the first embodiment shown in FIG.

A second result of this embodiment is illustrated in FIG. 13.

When the angle of inclination of the flap θ is set to a large value, the concentration coefficient of the coal fed to the specific burner (lower stage burner in the present embodiment) increases (equal to the volume of coal flow supplied to the branch pipe 16). In the present embodiment (see solid line), the aforementioned coal concentration coefficient increases relative to the concentration coefficient of the first embodiment (see dashed line). If the coal concentration coefficient towards the lower stage burner is held at the same _lower C value with the present embodiment and the first embodiment, the angle of inclination θ of the pipe 11 can be reduced from angle θ ₁ to angle θ ₂ .

The result of the influence of the angle of inclination θ of the flap on the pressure loss in the main pipe 4 in the position where the flap is installed will be reflected convex in the downward direction of the curve, as shown in the lower diagram of Fig.13. With the present embodiment, since the angle θ ₁ can be reduced to the angle θ ₂ , the pressure loss ΔP ₁ on the part where the shutter 11 is installed can be reduced to ΔP ₂ .

Fifth incarnation

The distributor for the fuel supply pipe of the embodiment shown in FIG. 14 is a distributor for the fuel supply pipe, which is a modification of the embodiment shown in FIG. 10. In this device, the main pipe 4 is installed with the main pipe 4a, which is oriented in the vertical direction of the part on which the shutter is installed, with the pipe 4b, which is oriented in a curved form and connected to the side upstream of the main pipe 4a through the elbow E, and vertically oriented pipe 4c, which is installed through the elbow E ′, that is, the elbows E and E ′ are provided in two locations, that is, the upper location and lower location of the main pipe 4, and, moreover, the offset O is established between the main E riser pipe 4a and 4c.

The designs of the other parts of the distributor for the fuel supply pipe shown in FIG. 14 are the same as the designs shown in FIG. 10. Due to the aforementioned displacement O, the mixed fluid that has passed through the main pipe 4c collides with the upper part of the wall of the pipe 4b. The mixed fluid, consisting of a two-phase flow of solid particles - gas, thus changes with respect to the direction of flow by the upper part of the wall of the main pipe 4b, and after reaching the damper 11 in the main pipe 4a, changes again with respect to the direction of flow in the opposite direction by the angle of inclination θ. As a result of its inertia, the flow of the solid phase in the mixed fluid flows towards the wall of the main pipe 4a, which is closer to the branch pipe 16 connected to the lower stage burner. Thus, in a manner similar to the result described with reference to FIG. 10, the concentration and volume of the flow of coal particles (solid phase) in the mixed fluid that flows towards the branch pipe 16 connected to the lower stage burner increases compared to characteristics of the mixed fluid that flows towards the branch pipe 15 connected to the upper stage burner.

The distributor for the fuel supply pipe of this embodiment can be installed with a simple orientation when the wing mill 3 is displaced relative to the main pipe 4a by the same value as the aforementioned offset O.

Sixth incarnation

The embodiment shown in FIG. 15 is also a manifold for a fuel supply pipe, which is a modification of the embodiment shown in FIG. 10. In this distributor, the main pipe 4 is installed with branch pipes 15 and 16, which branch and are connected to the upper stage and lower stage burners not shown, respectively, the shutter 11, which rotates around the rotary axis 11a of the shutter, is located on the upstream side at the branch point 14, and the rotating pinwheel 22 with the axis of rotation 22a is positioned even further upstream relative to the shutter 11. The axis of rotation 11a of the shutter and the axis of rotation 22a are located in the direction perpendicular to the main axis of the main pipe 4. The axis 11a of rotation of the shutter and it can be mounted on the upper end part of damper 11 as shown in Figure 2.

The distributor for the fuel supply pipe shown in FIG. 15 corresponds to a device in which the distributor for the fuel supply pipe of the embodiment shown in FIG. 4 is further provided with a rotary turntable 22 and a rotation axis 22a.

When rotation is reported in the direction of the arrow In the rotary turntable 22, when the angle of inclination θ of the shutter 11 corresponds to the inequality 0 <θ <90 °, coal particles that flow into the region in which the rotary turntable 22 is installed will contribute to a two-phase flow of solids - gas the side of the main pipe 4 (the right side in FIG. 15), which is closer to the branch pipe 16, and collide with the flow on the side of the main pipe 4 (the left side in FIG. 15), which is closer to the branch pipe 15 of the central axis 21a. As a result, the concentration of coal particles in the mixed fluid in the main pipe 4 in the vicinity of the part on which the shutter 11 was mounted will be high on the side of the main pipe 4, which is closer to the branch pipe 16, and will be low on the side of the main pipe 4, which is closer to branch pipe 15. Thus, as in the case of the fourth embodiment shown in FIG. 10 and the fifth embodiment shown in FIG. 14, the concentration and volume flow of the coal particles in the mixed fluid flowing towards the branch are increased. an existing pipe 16 connected to a lower stage burner compared to the characteristics of a mixed fluid flowing towards a branch pipe 15 connected to a upper stage burner.

The results unique to the present embodiment are that there is no need to bend the main pipe 4, and that when the angle θ of the slope of the shutter 11 satisfies the inequality -90 ° <θ <0, the concentration and volume of the flow of coal particles in the mixed fluid flowing towards the branch pipe 15, compared with the characteristics of the mixed fluid flowing towards the branch pipe 16, can be quickly implemented by setting the direction of rotation of the rotating turntable 22, opposite an arrows B.

Also in the present embodiment, since strong mechanical rotation can be imparted to the two-phase flow of solids - gas by means of the rotating pin 22 even when there is a biased flow in the main pipe 4 on the side upstream of the rotating pin 22, this biased flow can be corrected faster than the above fourth and fifth incarnations.

In the fourth and fifth embodiments, since the curved part E and / or E ′ is installed, the pressure loss increases compared to the case where the main pipe 4 is a straight pipe. However, since the cross-sectional area of the flow path of the main pipe 4 does not decrease, the decrease in pressure loss on the part on which the shutter 11 is mounted will be much larger than the increase in pressure loss due to the presence of a bent part. That is, since the displaced flow is already deliberately formed on the upstream side of the shutter 11, the angle θ of the portion of the shutter 11 can be set much smaller, and the pressure loss due to the presence of the shutter 11 can thus be significantly reduced. In the present embodiment, although the cross-sectional area of the flow path of the main pipe 4 is reduced in relation to statics, there will be almost no pressure loss on the part where the rotary turntable 22 is installed, since the rotational speed of the rotary turntable 22 can be set much higher than the mixed fluid flow rate Wednesday.

Seventh and eighth incarnations

Fig.16 is a view in longitudinal section of the main parts of the distributor for the fuel supply pipe of the seventh embodiment of this invention; Fig.17 is a view in longitudinal section of the main parts of the distributor for the fuel supply pipe of the eighth embodiment, which is a modification of the embodiment shown in Fig.16, and Fig. .18 is a diagram that illustrates the distribution characteristic of the distributor of FIG. 16.

As described with reference to Fig.21 and Fig.22, coal particles, which are transported by the blade 17 of the impeller of the vane mill 3 and through the sorter 18 lead to an increase in bias in the two-phase flow of solids - gas in the main pipe 4, so that the coal stream d high concentration or a stream of coal of high concentration can be formed relative to the direction of the cross section of the pipe in a two-phase flow of solids - gas.

In this case, as shown in FIG. 19, if, for example, the shutter is installed inside the main pipe 4 in an inclined position in the direction of supply of coal to the branch pipe 16, which leads to the burner of the lower stage, and the mixed fluid is biased so that the distribution b, the concentration of coal in the direction of the cross section in the main pipe 4 on the side upstream of the shutter 11 will be such that the concentration of coal increases from the central part of the pipe 4 towards the branch pipe 15 for the upper stage burner, the flow is high ontsentratsiey coal passing through the space between the end portion of flap portion 11 and the wall of the main pipe 4 without colliding with damper 11, increases and the volume of coal flow flowing in the branching pipe 15 to the upper stage burner, also increases.

Fig. 18 shows the relationship between the passage of the main pipe 4 in the cross-sectional direction formed by the shutter 11 and the concentration coefficient of coal particles (towards the branch pipe 16 leading to the lower stage burner), and with the device shown in Fig. 19, the concentration coefficient of coal particles in the direction of the branch pipe 16 leading to the lower stage burner, in the case where there is a displaced flow of coal particles in the main pipe 4 on the side upstream of the part on which the shutter is installed 11 (see the dashed line) may be lower than the concentration coefficient of coal particles in the case where there is no displaced flow (see the dashed line).

As a countermeasure to overcome the aforementioned drawback of the first embodiment illustrated in FIG. 19, in the seventh embodiment, a distributor for the fuel supply pipe of the device shown in FIG. 16 was used.

The seventh embodiment has a device in which an annular restrictive element 24 is provided on the inner wall of the main pipe 4, extending in the vertical direction, a shutter 11 is provided, provided with a pivot axis 11a, in parts downstream of the restrictive element 24, and branch pipes 15 and 16, which branch and connected to the upper and lower stage flaps not shown in the drawing, respectively, located downstream of the main pipe 4, in which the valve 11 is installed.

Due to the aforementioned restriction element 24, the mixed fluid stream C, consisting of a two-phase flow of solids - gas, narrows first towards the main axis, and then diverges after passing through the restriction element 24. The distribution of the concentration of coal particles in the cross section direction of the main pipe 4 is becomes homogeneous when passing through the restriction element, and then a mixed fluid flows having a high concentration of coal particles on the branch side yuscheysya pipe 16.

Thus, even if the two-phase solid-gas flow is biased towards the branch pipe 15 for the upper stage burner in the main pipe 4, since the amount of coal passing through the space between the lower end portion of the shutter 11 and the wall of the main pipe 4 shown in FIG. .19 decreases, a good distribution characteristic can be obtained.

Fig. 18 shows a characteristic of the distribution of coal particles towards a branch pipe 16 leading to a burner of the lower stage of the device shown in Fig. 16.

In the present embodiment, even when there is a biased flow in the mixed fluid in the main pipe 4 on the upstream side of the part on which the shutter 11 is mounted, since the restrictor 24 is installed, reducing the concentration coefficient of the coal particles towards the branch pipe 16, leading to the lower stage burner does not take place, and a good distribution characteristic equivalent to the distribution characteristic in the case where there is no biased flow can be obtained.

The eighth embodiment shown in FIG. 17 is a modification of the device shown in FIG. 16, and in this embodiment, a pair of restriction elements 25 and 26 that can be height-adjusted in the cross-sectional direction of the main pipe 4 are mounted on the inner walls of the main pipe 4 on the upstream side of the part where the shutter 11 is installed in the main pipe 4 having a rectangular cross section. In the case where, for example, the coal particles must be fed in condensed form to the branch pipe 16 for the lower stage burner, since the concentration of coal particles supplied to the branch pipe 15 for the upper stage burner should be reduced to the part where the shutter 11 is installed, the height L _{1 of the} height-adjustable restriction element 25 mounted on the side of the branch pipe 15 for the upper stage burner is set large, and the height L _{2 of the} height-adjustable restriction element 26 mounted on the side of branching pipe 16 for the opposite burner of the lower stage, set the smallest, as shown in Fig.17.

It is thus possible to avoid a useless increase in the pressure drop inside the main pipe 4. Thus, it will be preferable to adjust the heights L ₁ and L _{2 of the} restriction elements 25 and 26 with respect to the inner diameter D of the pipe in the ranges 0≤L ₁ / D≤0.3 and 0 ≤L ₂ / D≤0.3.

Ninth and tenth incarnations

On Fig and Fig shown respectively fuel distributors for the fuel supply pipe of the ninth embodiment and the tenth embodiment.

The ninth embodiment shown in FIG. 24 is an example where the branch pipe 16 connected to the lower stage burner in the fuel supply pipe structure of the first embodiment is provided with a shutter 28 by which the passage area of the branch pipe 16 can be changed from a fully open to a fully open state closed state, and the tenth embodiment shown in FIG. 25 is an example where a branch pipe 16 connected to a lower stage burner in the structure of the fuel feed pipe is a quarter second embodiment is provided with a shutter 29, whereby the area can be changed by the passage of the branch pipe from a fully open state to fully closed state.

The branch pipes 15 and 16 of the fuel supply pipe structure shown in the aforementioned Figs. 24 or 25 are connected respectively to burners 5 of a plurality of steps formed in the height direction of the walls or parts of the corner walls of the boiler furnace 8, shown schematically in Fig. 20. A damper 11, the angle of inclination of which can be changed with respect to the direction of flow of the mixed fluid, is installed inside the fuel supply pipe 4 on the side upstream of the branch pipes 15 and 16 (Figure 1, etc.), at least branching the pipe 16 connected to the lower stage burner is provided with a shutter 28 or a shutter 29, by means of which the passage area of the branch pipe 16 can be changed from a fully open state to a completely closed state. Although the branch pipe 15 may also be provided with a shutter 28 or a shutter 29, with which you can change the passage area of the branch pipe 15 from a fully open state to a fully closed state, this is not shown here.

A heat exchanger pipe 9 is installed in the furnace 8 of the boiler, an example of which is shown in FIG. 20, and a heat exchanger pipe not shown is also installed in an unshown flow path at the furnace outlet. Moreover, the heat exchanger tube is mounted on the unshown back of the heat exchanger, the gas flow paths on the downstream side of the furnace outlet.

As already explained in the part of the description related to the prior art, during operation at full load (100% load) of the boiler, the gas temperature at the outlet of the boiler furnace, when the combusted gas reaches the rear of the heat exchanger of the furnace 8, is set below the melting point ash contained in the gas, and is set such that the temperature of the metal surface of the heat exchanger pipe, which contains the aforementioned rear part of the heat exchanger, will not increase sharply to or above the surface heat resistance temperature. However, when the boiler switches from the full load operation mode to the partial load operation mode, since the amount of heat at the furnace inlet 8 decreases, the gas temperature at the boiler furnace outlet also decreases, as does the steam temperature at the boiler outlet.

Thus, in the ninth and tenth embodiments, the valve 11 of the fuel supply pipe 4 is controlled during the start-up of the boiler, and the valve 28 or 29 inside the branch pipe 16 is manipulated, and it opens the supply of coal particles in condensed form to the branch pipe 16 connected to the lower stage burner, and when, when the load changes after stabilization of combustion, when the load changes from full to low, the shutter 28 or 29 in the aforementioned branch pipe 16 connected to the lower stage burner is manipulated in the closed direction i.

By adjusting the shutter 11 in the fuel supply pipe 4 and by opening the shutters 28 or 29 in the branch pipe 16 connected to the lower stage burner, during the boiler start-up, coal particles can be fed in condensed form to the branch pipe connected to the lower stage burner and is provided burning fuel on the burner 13 of the lower stage during the start-up of the boiler when the burning of fuel is unstable. So, when the boiler enters the low-load operation mode from the high-load mode, in which stable combustion of fuel has been achieved, the shutter 28 or 29 in the branch pipe 16 connected to the aforementioned lower stage burner 13 is manipulated in the closing direction to make the gas temperature the outlet of the furnace is high enough to provide the required temperature of the steam on the side of the consumed steam.

Although examples have been given in which the shutter 28 or 29 is installed in only one branch pipe 16 of the two branch pipes 15 and 16 shown in FIGS. 24 and 25, the shutters can be installed in both pipes 15 and 16. In this case, as shown in the examples illustrated in Figs. 24 and 25, a shutter is installed in the branch pipe 15 of the upper stage side, in addition to the branch pipe 16 of the lower stage side.

When the shutter 28 or 29 in the branch pipe 16 connected to the lower stage burner is manipulated in the closing direction after the boiler load changes from high to low, the shutter installed in the branch pipe 15 is opened.

So, when installing the dampers in both branch pipes 15 and 16, the shutter (not shown) in the branch pipe 15 connected to the upper stage burner can be manipulated in the closing direction when the gas temperature at the outlet of the furnace must be lowered, thus allowing regulation temperature at the outlet of the furnace.

The above embodiments 1-10 can be easily implemented and are intended not only for mixed fluids (two-phase flows of solids - gas), but also for other two-phase flows that differ in density.

Industrial applicability

Thanks to this invention, at appropriate coal concentrations, the coal particles can be distributed over a plurality of burners regardless of the type of coal, load size, etc., in order to improve ignition and ensure stable burning near the burners.

In particular, since coal particles of appropriate coal concentrations can be distributed over many burners, the formation of a stable flame near the burners is improved, and since stabilization of the flame by means of separately installed burners is useless, the combustion of coal in the furnace is stabilized even in the area of low boiler load, where it is necessary reduction in the number of mills. Thus, it is possible to work in a wide range with adjustable load.

Also, thanks to this invention, the shutter can be installed with the possibility of tilting relative to the direction along the flow of the mixed fluid, and with a device in which a bend (bent part) is provided in the fuel supply pipe (main pipe), while the pressure loss does not increase, since the area of the pipe flow path does not decrease.

Moreover, thanks to this invention, a mixed fluid of high coal concentration can be supplied to a specific burner even when there is a biased flow of a two-phase solid-gas stream at the inlet side of the part on which the shutter is mounted. And this is possible even in the case when various auxiliary equipment is installed in the fuel supply pipe (main pipe) on the upstream side of the part on which the shutter is installed, and the characteristic of supplying a mixed fluid of a high concentration of coal to the specific burner in pieces, by which the shutter is installed will not deteriorate, and the arrangement of various equipment can be easily designed. The time required to design a fuel supply system can thus be reduced, and the equipment can be made more compact.

Thanks to this invention, in the case when a boiler using a mixed fluid including solid fuel and its carrier gas is switched from full load to partial load, the boiler can be activated in such a way that the temperature of the steam at the outlet of the boiler will not decrease below the temperature required on the side of the consumed steam.

Claims (10)

1. A fuel distributor for a fuel supply pipe including a fuel supply pipe that delivers mixed fluid, including, in turn, solid fuel and carrier gas, to each one or more burners disposed on walls or corner portions formed the walls of the furnace, a lot of branching pipes branching from the branching part formed in said fuel supply pipe, and each of which is connected to a corresponding burner, and a shutter placed inside the fuel supply pipe on the side above the flow of a branching part, the inclination angle of which can be changed relative to the direction of flow of the mixed fluid, while the axis of rotation of the damper for changing the angle of inclination of the said damper is located on the end part of the damper or the central part of the damper, and the said axis of rotation of the damper is located in the central part of the supply pipe fuel with a device by which the following relation is observed for the distance L from the said axis of rotation to the said branching part in the flow direction is mixed fluid, and the diameter D of the pipe for supplying fuel in the part that lies upstream relative to the said branching part: L / D = 0.4-2, so that the mutual difference will occur in the concentration of solid fuel of the mixed fluid, fed to the respective branch pipes, allowing the concentration of the solid phase to be raised for a particular burner from a plurality of burners. 2. The fuel distributor for the fuel supply pipe according to claim 1, wherein the angle of inclination of said damper relative to the direction of flow of the mixed fluid can be changed within a range of ± 40 °. 3. The fuel dispenser for the fuel supply pipe according to claim 1, wherein a rotating pinwheel that mixes the mixed fluid stream is housed in the fuel supply pipe on the upstream side of said damper. 4. The fuel distributor for the fuel supply pipe according to claim 1, wherein said fuel supply pipe is arranged so that the mixed fluid flows in a vertical direction and is provided with a first fuel supply pipe in which said shutter is installed, and a second a fuel supply pipe mounted on an upstream side of said first fuel supply pipe and bently connected to said first fuel supply pipe. 5. The fuel dispenser for the fuel supply pipe according to claim 4, wherein said second fuel supply pipe is bent in a direction in which the mixed fluid will be directed so as to increase the differential pressure in the solid fuel concentrations of the mixed fluid supplied to corresponding branch pipes caused by said damper. 6. The fuel dispenser for the fuel supply pipe according to claim 4, wherein the third fuel supply pipe, causing the mixed fluid to flow in a vertical direction, is connected on the upstream side of the second fuel supply pipe. 7. The fuel distributor for the fuel supply pipe according to claim 1, wherein the restrictor restricting the flow of the mixed fluid is placed in the fuel supply pipe on the upstream side of the shutter. 8. The fuel dispenser for the fuel supply pipe according to claim 7, wherein said restrictor has a device for changing the degree of restriction in order to increase the difference in the concentration of solid fuel of the mixed fluid supplied to the respective branch pipes due to said damper. 9. The fuel dispenser for the fuel supply pipe according to claim 1, wherein the branch pipe damper, by which the passage area of the branch pipe can be transferred from a fully open state to a fully closed state, is installed inside at least one branch pipe, connected to a particular burner from a plurality of burners placed in the vertical direction of the walls of the furnace or the corner parts formed by the walls. 10. The method of operation of the boiler for burning solid fuel, which consists in the fact that the coal particles that have been atomized by a single mill for crushing coal are supplied together with the carrier gas through a fuel supply pipe and a plurality of branch pipes that branch from said supply pipe fuel for each of the burners, which correspond to branch pipes and which are placed at a number of steps in the direction of the height of the walls of the furnace or the angular parts formed by the walls of the furnace, moreover, a flap, the angle of which can be changed relative to the direction of flow of the mixed fluid, including solid fuel and carrier gas, installed inside the fuel supply pipe on the side upstream of said branch pipes, another damper by which the passage area of the branch pipe can be changed from a fully open state to a fully closed state is installed inside at least one branch pipe of said branch pipes, which is connected to a lower stage burner, said the removed valve of the fuel supply pipe is adjustable, and the other valve in the branch pipe connected to the lower stage burner works in the opening direction, so that the coal particles are condensed when the boiler is started up and when the load changes after stabilization the combustion load is changed from high load to low load, said other damper in the branch pipe connected to the lower stage burner operates in the closing direction.

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