RU2396486C1 - Reactor feed water circuit with fluidised bed and reactor with fluidised bed with such feed water circuit - Google Patents

Abstract

FIELD: power engineering. ^ SUBSTANCE: circuit comprises down-take pipe (26) and multiple horizontal inlet headers (30), having length equal to length of front wall (14) of vessel furnace, arranged under vessel furnace and panel (18) of steam-generating tubes (16) in front wall (14) and back wall, extension pieces of steam-generating tubes of front wall (14) and back wall connected directly to inlet headers. Besides each inlet header communicates along flow with down-take pipe (26) only by means of inlet nozzle (28), which is connected to the end of inlet header. Inlet headers comprise inlet header of front wall arranged under front wall (14) pf furnace, and inlet header of back wall arranged under back wall of furnace, and at least one inlet header of furnace grid under central part of furnace grid inside air chamber of vessel with fluidised bed. ^ EFFECT: invention provides a simple and reliable feed water circuit for the vessel. ^ 11 cl, 3 dwg

Description

The present invention relates to a boiler water circuit of a fluidized bed boiler (PS boiler) and to a fluidized bed boiler having such a boiler water circuit in accordance with the introductory part of claim 1. This invention in particular relates to a boiler water circuit of a 400 MW supercritical pressure boiler with a circulating fluidized bed (DSP), operating on a once-through basis.

In PS boilers, as in any other thermal energy boilers, vaporization, i.e. boiling, of preheated incoming water occurs mainly through panels of boiling tubes located on the outer walls of the boiler furnace. The water to be evaporated is, for the most part, supplied either from the steam manifold of the drum boiler or from the surfaces of the water heating in the direct-flow energy boiler to the lower part of the boiler using one or more lowering pipes. The downpipe is usually connected to a plurality of inlet nozzles, through which water is introduced into the inlet manifolds located under the furnace, these intake manifolds have a length corresponding to the width of the furnace walls. The heating pipes in the panels of the heating pipes of the outer walls of the furnace are in turn connected to the intake manifolds for heating and evaporating water in the heating pipes. The heating pipes of the outer walls are connected with the upper end to the exhaust manifolds and pipes, through which the steam is directed further to separate the water and superheat.

In order to guarantee an even distribution of water in the boiler pipes of the boiler pipe panel, the downpipe is usually connected to a large number of inlet pipes which are connected at one end at approximately equal intervals over the entire length of the inlet manifolds. Direct-flow energy boilers that have such a large number of inlet nozzles are disclosed, for example, in US Pat. No. 4,290,389, US Pat. No. 3,399,656, and US Pat. No. 3,396,926. US Pat. No. 4,183,330 discloses an example of a boiler PS having a plurality of inlets connecting the downpipes of a steam drum to an annular inlet. a collector supplying water to the furnace screen pipes.

The lowering pipe can be essentially vertical, due to which it usually ends outside the lower plane of the boiler or its lower part, can be rotated horizontally, having then the ability to pass as such under one of the walls of the boiler. In the latter case, the intake manifolds of the intake manifolds connected to the wall may be relatively short. Especially when two downpipes are present, they can preferably extend under the longer side walls, in other words, the front wall and the rear wall, or alternatively, under their shorter side walls.

The boiler water circuits described above are working solutions as such, but in large boilers they can become quite complex. The boiler water circuit becomes particularly complicated when the furnace grate is also cooled by evaporator pipes and, due to the large size of the furnace grate, it is preferable even in drum boilers to have one or more intake manifolds so that they extend longitudinally under the central part of the grate fireboxes. Especially with boilers with a fluidized bed, the placement of the inlet nozzles of the so-called inlet manifold of the grill is problematic, since also the suction chamber of the fluidizing air, the so-called air chamber, must be placed in the boiler with a fluidized bed under the grill. If the air chamber needs to be installed as one large undivided structure, which is preferable due to the homogeneous distribution of air, then the intake manifold of the grill, as a rule, should be placed inside the air chamber. Thus, multiple inlets must be routed through the air chamber.

An object of the present invention is to provide a boiler water circuit of a fluidized bed boiler that reduces problems related to boiler water circuits of a fluidized bed boiler in accordance with the prior art.

In particular, the object of the present invention is to provide a simple and reliable boiler water circuit of a supercritical pressure boiler with a circulating fluidized bed operating on a once-through basis.

Another objective of this invention is to provide a fluidized bed boiler having such a boiler water circuit.

In order to solve the aforementioned problems of the prior art, a boiler water circuit of a fluidized bed boiler and a fluidized bed boiler having a similar boiler water circuit are provided, and their distinguishing features are presented in the characterizing part of the independent claims of the device.

Thus, the boiler water circuit of a fluidized bed boiler in accordance with the present invention comprises a downcomer and a plurality of horizontal inlet manifolds of substantially a length equal to the length of the front wall of the boiler furnace, located under the furnace of the fluidized bed boiler, panels of the front wall and rear wall boiler tubes extensions of boiling pipes connected directly to the intake manifolds, and each intake manifold communicating downstream with the downcomer only via the inlet th nozzle attached to the end of the intake manifold.

The fluidized-bed boiler furnace is usually rectangular in horizontal section, and the front wall of the furnace and the rear wall of the furnace are usually referred to as long walls of the furnace. The short side walls of the furnace may preferably also be cooled in accordance with the present invention, but it is possible that water is supplied to the short walls of the furnace by a conventional method using a plurality of inlets. A third alternative, which is especially the subject of discussion when the lengths of the long or short walls of the furnace are relatively close to each other, is that the short walls of the furnace are cooled in accordance with this invention and the long walls in the usual way.

When each inlet manifold is in fluid communication with the downpipe in accordance with the present invention, preferably with only one downpipe, only by means of an inlet pipe connected to the end of the inlet manifold, the complexity caused by the numerous inlet pipes is eliminated. The connection to the end of the intake manifold refers in this connection to either the intake manifold connected in parallel to the intake manifold, directly to its end, or to the intake manifold attached to the side wall of the intake manifold, but essentially to its closest end. Such an arrangement in accordance with this invention is particularly preferred in large circulating fluidized bed boilers in which an undivided air chamber is required to enable a homogeneous flow of the fluidizing gas. The manufacture of such is greatly hindered by numerous inlet pipelines of the prior art.

Naturally, the disadvantage of the arrangement in accordance with the present invention is that the inner diameters of the intake manifolds must be large enough to ensure a sufficient flow of boiler water also to the far end of the intake manifold. The required size of the intake manifolds thus depends on the amount of water supplied, but according to a preferred embodiment, the inner diameter of the intake manifolds should be at least 200 mm, most preferably at least 300 mm. Large intake manifolds as such increase costs, but the author of the present invention unexpectedly noticed that with large PS boilers, especially direct-flow DSC supercritical boilers with an output power of at least 400 megawatts, it is preferable to use the very simple arrangement of the intake manifolds described above for boiler water.

Especially when the boiler water circuit in accordance with the invention is a supercritical single circuit, a very simple and preferred arrangement is provided when only one downcomer is present, whereby each of the intake manifolds is in communication with one common downcomer.

To solve the tasks, a boiler fluidized water circuit of the boiler (10) with a fluidized bed containing a downcomer (26) and many horizontal intake manifolds (30, 48, 50, 52, 54), essentially having a length equal to the length of the front wall (14 ) the furnace (12) of the boiler, located under the furnace of the fluidized-bed boiler, and the panel (18) of the heating tubes (16) of the front wall (14) and the rear wall (38), lengthening (44, 46) of the heating tubes of the front wall (14) and a rear wall (38) connected directly to the intake manifolds, each intake manifold the collector is in communication with the down pipe (26) only through the inlet pipe (28) connected to the end of the intake manifold. The circuit is characterized in that the intake manifolds comprise an front wall intake manifold (48) located under the furnace front wall (14) and a rear wall intake manifold (50) located under the furnace rear wall (38), and at least one the intake manifold (52, 54) of the furnace grate under the central part of the furnace grate inside the air chamber (20) of the fluidized bed boiler.

Preferably, the boiler water circuit is a supercritical once-through circuit. In a preferred embodiment, each intake manifold is in communication with only one downcomer pipe (26). In another preferred embodiment, each intake manifold is in fluid communication with a common downpipe (26).

One section of extensions (44) of the heating pipes in the front wall (14) can be connected directly to the front wall intake manifold (48), and the extension section (46) of the heating pipes in the rear wall (38) is connected directly to the rear wall intake manifold (50) and another section (54 ') of the heating pipes in the front wall and another section of the heating pipes in the rear wall run parallel to the furnace grate in the form of grating tubes (42) connected to the inlet manifold (52, 54) of the furnace grate.

Preferably, the diameter of the heating tubes (54) in the front wall (14) and the rear wall (38) is smaller than the diameter of the grill tubes (42), and each heating tube of said other portion of the heating tubes of the front wall and the rear wall is connected to the grille tube via a connecting element (56 )

The intake manifolds may contain two inlet manifolds (52, 54) of the furnace grate, and said other section of extension of the heating pipes in the front wall (14) is connected to the first inlet manifold (52) of the furnace grate, and said other section of extension of the heating tubes in the rear wall ( 38) is connected to the second intake manifold (54) of the furnace grate.

Preferably, the inner diameter of the intake manifolds is at least 200 mm, and more preferably at least 300 mm.

The intake manifold (52) of the furnace grate can be configured to function as a support element of the furnace grate.

Also proposed is a fluidized bed boiler (10) containing the above described boiler water circuit.

According to a preferred embodiment of the present invention, the intake manifolds comprise a front wall intake manifold located under the front wall of the furnace, a rear wall intake manifold located under the rear wall of the furnace, and at least one so-called intake manifold of the grill under the central part of the furnace grill . In this preferred embodiment, typically the first portion of the extensions of the heating pipes in the front wall of the furnace is connected directly to the intake manifold of the front wall, and accordingly, the first section of the extensions of the heating pipes in the rear wall of the furnace is connected directly to the intake manifold of the rear wall. According to this arrangement, not all the heating tubes of the front wall and rear wall heating tubes panel are connected to the aforementioned front wall intake manifold and rear wall intake manifold, but the second portion of the front wall and rear wall heating tubes continues in the form of grating tubes parallel to the furnace grate to the inlet collector grille. Using this arrangement, it is also possible to ensure uniform distribution over all the tubes of the grate. The intake manifolds of the grill are preferably located under the grill of the furnace, inside the air chamber.

Since the requirements for the strength of the grill tubes are higher than the requirements for the strength of the boiling tubes of the front walls and the rear walls, and since there should be enough space between the grille tubes for the nozzles for fluidizing air, the grill tubes are usually larger in diameter than the heating tubes of the walls. Therefore, each lattice tube is preferably connected by means of a special connecting element to a heating pipe of the aforementioned second heating pipe section in the front wall or the rear wall.

It is preferable in large boilers to have two grill inlet manifolds, whereby the second extension section of the heating pipes in the front wall is preferably connected to the first intake manifold of the grill, and the second extension section of the heating pipes in the rear wall is connected to the second intake grille. The heating pipes of the first and second sections are preferably alternated in the front wall and the rear wall, whereby, for example, every second heating pipe of the front wall is connected to the front wall intake manifold, and the remaining heating pipes are connected to the first intake manifold of the grill.

A significant additional advantage of large intake manifolds is that they can be placed as supporting elements of the lower part of the furnace, whereby they reduce many other supporting elements. Especially in large PS boilers, it is possible to simplify the support of the central part of the furnace grate when the large intake manifold of the grate in accordance with a preferred embodiment of the present invention forms part of it.

The invention will be discussed in more detail with reference to the accompanying drawings, in which:

1 schematically shows a side view of a circulating fluidized bed boiler containing a boiler water circuit in accordance with a preferred embodiment of the present invention;

2 schematically shows a vertical sectional view of the lower part of a circulating fluidized bed boiler containing a boiler water circuit in accordance with a preferred embodiment of the present invention;

3 schematically shows an element of the lower part of the boiler tubes of a circulating fluidized bed boiler in accordance with a preferred embodiment of the present invention.

Figure 1 shows a DSP boiler 10 in accordance with a preferred embodiment of the present invention, comprising a furnace 12. The boiler in accordance with the invention may be a natural circulation boiler, in other words, a drum boiler, but a direct-flow supercritical energy boiler, which is shown, is most preferred. , for example, in figure 1. The horizontal section of the firebox is usually a rectangle, and it (the firebox) is bounded by a hearth (the bottom of the firebox), a ceiling, and side walls, of which one long side wall, the so-called front wall 14, is shown in the drawing. The walls restricting the furnace are usually made in the form of a screen design of heating pipes, in other words, of heating pipes 16 and plates connected gas-tight between them. Boilers and plates form panels 18 of boilers that are used to boil water, that is, to convert pre-heated feed water into steam.

The so-called air chamber 20 is located under the furnace for supplying primary gas, usually air, necessary for burning fuel and for fluidizing (creating) a fluidized bed to the furnace. Other common components of the boiler DSP, such as a fuel supply device, exhaust channels for flue gases and slag, as well as particle separators and recirculation channels related thereto, are also connected to the furnace. For simplicity, these elements not related to the present invention are not shown in FIG.

The pre-heated feed water 22 supplied from the surfaces of the pre-heated water, the so-called economizer, and the possible liquid returned from the steam separator 24 are supplied through the downcomer 26 to the bottom of the furnace, from where they are distributed through the inlet pipes 28 to the intake manifolds 30 of the evaporation tubes in the side the walls of the boiler. In accordance with conventional technology, multiple inlet nozzles are connected approximately equally spaced from each other along the entire length of the intake manifolds. This, however, is a feature of the present invention that each intake manifold 30 is connected downstream to the downcomer 26 only through the intake manifold 28 connected to the end of the intake manifold. To make this possible, the diameter of the intake manifolds 30 must, of course, be sufficient, substantially larger than the diameter in the arrangement of the prior art. The inner diameter of the intake manifolds in accordance with the invention is preferably at least 200 mm, most preferably at least 300 mm. The structure of the intake pipes in accordance with the invention is very simple, and it does not violate the arrangement of devices attached to the lower part of the furnace, for example, the design of an expanded, unshared air chamber 20.

Water from the intake manifolds 30 is supplied to the panels 18 of the evaporator tubes and then in the form of steam to the exhaust manifolds 32. If the boiler is a so-called drum boiler, then the force that moves water and steam upward in the panel is the weight of the water column in the drum lowering pipe . If, in turn, the boiler is a so-called boiler with forced circulation, especially the so-called once-through boiler of supercritical pressure, then the driving force is the pressure created by the feed pump (not shown in figure 1). Steam from the exhaust manifolds 32, possibly still containing a certain amount of liquid water, is supplied to the water and steam separator 24 [steam-water mixture separator] via manifold pipes 34. The steam continues to move further along the steam lines 36 to the superheaters located, for example, in the flue gas channel.

2 schematically shows a simplified vertical section of the lower part of the furnace 12 of a fluidized bed boiler having a water circuit in accordance with a preferred embodiment of the present invention. Figure 2 shows the front wall 14 and the rear wall 38, which are formed by the panels of the heating tubes of the furnace 12, as well as the air chamber 20. Figure 2 also schematically shows the air chamber 20 with the nozzles 40 of the fluidizing gas, which are located between the tubes 42 of the lattice.

Extensions 44, 46 of the first portion of the heating tubes in the front wall 14 and the rear wall 38 are connected directly to the front wall intake manifold 48 and the rear wall intake manifold 50, respectively. The front wall intake manifold 48 and the rear wall intake manifold 50 are both connected, as shown in FIG. 1, to the downcomer only by an inlet pipe connected to the end of the intake manifold. Thus, since there are no other inlet pipes connected to the intake manifolds, in accordance with the present invention, each section of the furnace 12 is simple, since there are no inlet pipes of the intake manifolds that make it difficult to connect other devices to the bottom of the furnace 12.

In the embodiment of FIG. 2, there are two other intake manifolds located inside the air chamber 20, the so-called first and second intake manifolds 52, 54 of the grill. The grill tubes 42 are connected to the grille inlet manifolds, each of which is preferably connected to the heating tube of the front wall 14 or the rear wall 38, as described below. Since the intake manifolds 52, 54 of the grille are also connected, as shown in FIG. 1, to the downcomer only by means of an inlet pipe connected to the end of the intake manifold, there are no intake pipes connected to the central part of the intake manifolds 52, 54 of the grill that would interfere the structure of an undivided air chamber. These intake manifolds 52, 54 of the grill, passing along the entire length of the walls of the boiler, also significantly strengthen the design of the grill of the furnace and, thus, reduce the need for other supporting structures.

Figure 3 schematically shows an element of the lower part of the boiler tubes of a circulating fluidized bed boiler in accordance with a preferred embodiment of the present invention. This drawing shows the front wall intake manifold 48, the first grill intake manifold 52, and the heating pipes attached thereto. Of course, the drawing may also show, respectively, heating pipes connected to the intake manifold of the rear wall and the second intake manifold of the grill. As shown previously in connection with FIG. 2, the grate tubes are preferably located along the central portion of the cross section of the grate of the firebox, and the length of the substantially horizontal portion of the grating tubes 42 parallel to the grate of the firebox is thus approximately half the entire width of the grate of the firebox.

The grill tubes 42 connected to the first grille intake manifold 52 first exit the grille intake manifold a certain distance upward and then rotate parallel to the furnace grill to the front wall 14, where they again rotate upward. Since the diameter of the grating tubes is preferably larger than the diameter of the heating tubes 54, 54 ′ of the furnace wall, the grating tubes are preferably connected via a connecting member 56 to the heating tubes 54 ′ of the furnace wall. Preferably, each second tube of the furnace wall relates to the so-called first section 54 of heating pipes, their extensions 44 connected directly to the front wall intake manifold 48, and the remaining pipes belong to the so-called second section 54 ', which is connected by connecting elements 56 to the heating pipes 42 and thereby with the first intake manifold 52 of the grill.

The present invention has been described with reference to some typical layouts. These layouts were not given to limit the scope of the invention, but the invention is only limited by the claims and the definitions given therein.

Claims (11)

1. The boiler water circuit of a fluidized bed boiler (10) comprising a downcomer (26) and a plurality of horizontal inlet manifolds (30, 48, 50, 52, 54) essentially having a length equal to the length of the front wall (14) of the furnace ( 12) the boiler, located under the furnace of the fluidized-bed boiler, and the panel (18) of the heating pipes (16) of the front wall (14) and the rear wall (38), the extension (44, 46) of the heating pipes of the front wall (14) and the rear wall (38) connected directly to the intake manifolds, with each intake manifold in fluid communication with the intake manifold pipe (26) only by means of an inlet pipe (28) connected to the end of the intake manifold, characterized in that the intake manifolds comprise an front wall intake manifold (48) located under the furnace front wall (14) and a rear wall intake manifold (50) located under the rear wall (38) of the furnace and at least one intake manifold (52, 54) of the furnace lattice under the central part of the furnace lattice inside the air chamber (20) of the fluidized bed boiler. 2. The boiler water circuit according to claim 1, characterized in that the boiler water circuit is a supercritical once-through circuit. 3. The boiler water circuit according to claim 1 or 2, characterized in that each inlet manifold is in communication with the stream with only one down pipe (26). 4. The boiler water circuit according to claim 3, characterized in that each inlet manifold is in communication with the common lowering pipe (26). 5. The boiler water circuit according to claim 1, characterized in that one section of the extensions (44) of the heating pipes in the front wall (14) is connected directly to the intake manifold (48) of the front wall, the extension section (46) of the heating pipes in the rear wall ( 38) is connected directly to the inlet manifold (50) of the rear wall, and another section (54 ') of the heating pipes in the front wall and another section of the heating pipes in the rear wall run parallel to the furnace grate in the form of tubes (42) for the grate connected to the intake manifold ( 52, 54) the grate of the furnace. 6. The boiler water circuit according to claim 1, characterized in that the diameter of the heating pipes (54) in the front wall (14) and the rear wall (38) is smaller than the diameter of the grill pipes (42), and each heating pipe of the above-mentioned section of the front heating pipes the wall and the back wall is connected to the tube of the lattice by means of a connecting element (56). 7. The boiler water circuit according to claim 5, characterized in that the intake manifolds contain two intake manifolds (52, 54) of the furnace grate, and the other extension section of the heating pipes in the front wall (14) is connected to the first intake manifold (52) of the grate firebox, and said other portion of the extensions of the heating pipes in the rear wall (38) is connected to the second intake manifold (54) of the combustion chamber grate. 8. The boiler water circuit according to claim 1, characterized in that the inner diameter of the intake manifolds is at least 200 mm. 9. The boiler water circuit according to claim 7, characterized in that the inner diameter of the intake manifolds is at least 300 mm. 10. The boiler water circuit according to claim 1, characterized in that the intake manifold (52) of the furnace grate is configured to act as a support element of the furnace grate. 11. The boiler (10) with a fluidized bed, characterized in that the boiler contains a boiler water circuit according to one of claims 1 to 10.

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