DE2060609A1 - Steam boiler operated with a fluidized fuel bed - Google Patents

Description

> Walter Meissner DipK-ing. Herbert Tischer

BERLIN-GRUNEWALD MUNICH

8 Munich 2, den

I ^{a! 71} oe «o«, December 9, 197ο

Fern sp. StSOSS7

Poster Wheeler John Brown Boilers Limited London / Great Britain

ivi steam boiler operated with a fluidized fuel bed

The original invention concerns one with a fluidized one fuel bed operated Jampfkessel.

fluidized fuel bed consists of a loose layer of fuel particles, most of which Ash particles and a small amount of coal are particles. the Lights are carried by the otrom of the combustion air, which flows through the fuel bed at sufficient speed to keep the particles suspended. As is well known, behaves Such a fluidized fuel bed of solid particles is similar to a boiling, turbulent liquid, Like particles of coal burn in the air, and to maintain it; Fresh coal particles are continuously fed to the incineration, and particles are continuously fed through an overflow (mainly ash particles) withdrawn, whereby the ßronnstoffbetthohe is kept essentially constant,

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The heat generated in the fuel bed can be used in various ways to generate steam. Oil pipes are preferably arranged in such a way that they are located in the fuel bed, so that very high heat transfer values can be achieved and satisfactory cooling of the fuel bed is obtained, as a result of which within the fuel bed the melting temperature of the ^ ash is not reached ₀

The task of the invention is the mode of operation a steam boiler operated with a fluidized fuel bed thanks to a special arrangement of the itpipes to improve the boiler

The one operated with a fluidized fuel bed Steam boiler according to the invention is characterized in that a row of substantially perpendicular tubes existing tube bundles is immersed in the fuel bed, which extends between an upper and a lower jamming tube extend and so side by side within the fuel bed are arranged so that the tubes of the j-bundle of ears are essentially evenly over the cross-sectional area of the fuel bed are distributed.

A significant advantage of this arrangement is that, as a result of the vertical arrangement of the ears, a step by step taking place separation of the steam in the ears, if They serve as low pipes, does not occur »^ This reduces them There is a risk of burns in the pipe with a horizontal arrangement of the pipes.

as already stated, can itohre because they are arranged vertically, substantially evenly over the _{1 (i} uerschnittsf pool of burn of f FCTs be distributed v / ground what f for uniform over the x'emperaturverteilung; Ad burning equipment FCOF f bed t is cheap.

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The inlet and outlet manifolds preferably run with respect to the cross section of the fuel bed in radial junction, i.e. they go in the superclinic surface geoelien from a central point of the fuel bed outward. The fuel bed is conveniently located in a cylindrical house, so that the cross-section of the burns offbettü is an area, with the inlet and outlet sainme ir öhre in radial alignment from the center of the cross-section aes fuel bed or from the .üChse of the -cylindrical Housing made of outwardly extending

±> is a preferred embodiment of the invention the ^ cross-section of the .u-bundle of ears, seen in the horizontal plane approximately sector-shaped, with ax sector area inside and outside is jaded. -üie tube bundles are in the fuel bed provided that they are distributed substantially evenly over the cross-sectional area of the fuel bed.

Tube bundles can all consist of boiler tubes On the one hand, when no superheater or reheater is required or a superheater or reheater is provided outside the fuel bed and heated by the hot combustion gases flowing out of the fuel bed. On the other hand, one or more hohrbündel inside the .fuel bed from superheater tubes and the rest of the tubes are made of lower tubes.

The cores of the itohr bundles are essentially vertical, however, the ends of the xiohre can be included in the inlet and outlet together 1 pipe must be bent »

According to a further embodiment of the invention the fuel bed is located in a cylindrical inner housing, aas is surrounded by a cylindrical outer housing. A hanging channel is present between the two housings, the ■

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flowed through by the iTuidisierungsluft in a downward direction before it flows through the fuel bed. This arrangement has the advantage that the inner housing, exposed to the high temperatures of the fuel bed is, with fluidizing air supplied under excess pressure compared to atmospheric pressure, only the pressure drop when the fluidizing air flows through the fuel bed is subject to while the outer casing that no has to withstand high temperatures, easily trained in this way v / can earth that it can withstand the internal overpressure.

./you already noticed, v / ground by means of an overflow Particles of the fuel bed withdrawn to keep the fuel bed height substantially constant. When building of the steam boiler according to the invention, so the pipes lying in the fuel bed run vertically, the Overflow for the particles through a tube open at the top od. The like. Be formed in the putty between all tube bundles is provided and through the fuel bed is guided below. This medium mess for the ash drawer aids in maintaining an even Fuel bed with level level.

If necessary, the lower collecting pipes can be located below an air distribution plate can be arranged, which forms a floor for the fuel bed, with the vertical pipes pass through the air distribution plate. In this version the air distribution plate contains a lower plate with circular openings for the passage of the pipes and between the tubes and the openings there are provided annular passages for the pluidizing air to pass through inverted, attached to the xtohren shells or the like. Covered to distribute the pluidizing air and prevent ash particles from entering the annular passages fall when the supply of pluidizing air is turned off.

109826/105 ^

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The drawing illustrates two examples of implementation of the invention, show:

U ¹ Ig. Fig. 1 is a diagram of the top b of the steam boiler according to the invention;

x ^{; i} ig. Fig. 2 is a vertical section through the main part of the steam boiler;

i ¹ ig. 3 shows a section "or _o is a plan view taken along the line 3-3 in I ¹ Ig. 2;

4 shows a vertical section through a second embodiment;

S ¹ Ig. 5 shows a partial section through the air distribution plate according to FIG. 4 on a larger scale.

The steam boiler shown in Fig. 1 to 3 of the drawing 1o has a furnace 11 operating with a fluidized fuel bed. The fluidized fuel bed 14 is located in a cylindrical inner housing 12. The upper level of the fuel bed 14 is indicated at 15. The inner housing 12 is closed at the bottom by a perforated air distribution plate 16 through which the fluidizing air is evenly distributed over the fuel bed 14. The inner housing 12 is made up of a cylindrical outer housing 18 and between the two housings 12 and 18 there is an annular channel 2o, through which a ring channel 2o flows Fluidizing air down to the air distribution plate 16. when the fluidizing air has a pressure above atmospheric Has pressure, the outer housing 18 must be designed so that it can withstand the excess pressure, while the inner housing 12 is only subject to the slight pressure drop that occurs when the air flows through the air distribution plate 16 and the

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2060809

Fuel bed 14 is created. However, the inner housing 12 is exposed to the high temperature of the fuel bed 14, while the outer housing 18 is not subject to this high temperature.

Within the fuel bed 14 there is a large number of substantially vertically arranged tubes 22 which extend between lower inlet manifolds 24 and upper outlet liner tubes 26. All of the laminate tubes 24, 26 run in the radial direction with respect to the circular cross-section of the fuel bed 14, each outlet collector tube 26 above an inlet collector tube? 24 lies. The tubes 22 are also arranged in groups, each group being provided between an inlet manifold 24 and the associated outlet manifold 26 above it, so that a number of tube bundles 28 is formed. .. the best from JJ ¹ Ig. 3 shows, the cross-section of the tube bundle 28 etv / a is sector-shaped, the inner and outer surface of the lector being truncated. The tube bundles 28 are also arranged next to one another in such a way that they fill the entire area of the fuel bed 14, and the individual tubes 22 are distributed essentially uniformly over the cross-sectional area of the fuel bed 14.

The tube bundles 28 have according to .ii'ig. 3 such a cross-section that o-segments 3o remain, which do not contain any tubes, but these segments j> o can optionally also be filled with tubes 22. As a modification, the segments 3o can be separated from the fuel bed 14 by walls so that they can be used as a channel for the iluidization air instead of the annular channel 2o.

In the example shown, there are six Tube bundle 28 is present, but it can also be more or less Tube bundles are provided. The exact number and shape

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and their arrangement depends on the iorm and the general . Education of the fuel bed 14 from.

In order to keep the fuel bed 14 at a constant level, a middle tube 32 which is open at the top is provided, which represents an overflow or .tiuslaß. This jctohr 32 goes through the air vertex latte 16 and through the Bottom of the .außengehäuses 18 through and is on an .aschebehäuses (not shown) connected, i ^ in constant The flow of ash particles passes over the edge of the tube 32 downward so that the fuel bed 14 is kept at a constant height when fresh coal dust passes through the capped. ^ inlJLsse 33 is fed.

The hot fluidizing air or the combustion gases from the fuel bed 14 are normally in a dust collector 36 passed to separate entrained particles. The separated particles can simply be fed through an outlet pipe 34 are fed into the pipe 32, but the entrained ones Particles still have a significant proportion of coal dust may contain them in the lower 'salvation of the fuel bed 14 are returned.

Each tube bundle 28 may consist of low tubes. In this case, the boiler can without superheater be formed ÄK or it can be a with ivonvektion working superheater in which the fuel bed leaving air stream or exhaust gas stream, for example, above the fuel bed, disposed v / ground, .andererseits some tube bundle 28 may consist superheater pipes. For example, two diametrically opposite tube bundles 28 can be formed from superheater tubes, while the remaining four tube bundles consist of boiler tubes. In this case, additional superheater and / or oil and / or economizer tubes can be arranged above the fuel bed. The design of the steam boiler according to the invention therefore enables the tubes 22 to be used very differently.

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On the inner edge of the inner housing 12, water pipes can optionally be provided, which form additional drain pipes _o In addition, an economizer 38 can be provided downstream of the fuel bed 14 and the fluidizing air supplied to the fuel bed 14 can be preheated by the exhausting combustion gases. All of these measures do not form part of the invention, so that they do not need to be described in detail.

from Fig. 1 it can be seen that the supply of fluidizing air can take place by means of a turbine arrangement 39. The air is pressurized by means of a turbine which is driven by an exhaust gas turbine. The exhaust gases are passed through this exhaust gas turbine before entering a chimney (not shown) arrive.

The vertical arrangement of the tubes 22 prevents intermittent separation of steam and water in the .Rohren, which serve as lower pipes, which prevents the risk of pipes failing.

Another feature of the steam boiler 1o is the central pipe 32 serving as an overflow, which ensures a uniform discharge causes the excess ash particles and consequently contributes to an even fuel distribution and uniform temperature of the fuel bed can be maintained.

The steam boiler shown in Fig. 4 and 5 is the same essential to the steam boiler 1o according to Fig. 1 to 3 with the exception, that the air distribution plate 42 is designed differently. Except for the air distribution plate 42, the others are the same Parts of the steam boiler to the corresponding parts of the steam boiler Ιο. They are therefore provided with the same reference numerals and are not described again in detail.

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In the case of the steam boiler 4o, the air distribution plate 42 lies above the inlet collecting pipes 24 and the vertical ones Pipes 22 pass through the air distribution plate 42, as can be seen in detail in FIG.

The air distribution plate 42 contains a lower plate 44 with circular openings 46 through which the tubes 22 go through. The openings 46 have a larger diameter than the outer diameter of the tubes 22, so that between them and the plate 44 annular passages 48 are present. The plate 44 also has annular shapes on its upper surface Grooves 5o that surround the openings 46 «in this Grooves 5o protrude the flanges 52 from inverted shells 54- * which in turn are fastened to the tubes 22 and form parts of the air distribution plate 42. The arrangement is like this taken that those formed by the interior of the shells 5 ^ Passages 56 on the one hand with the passages 48 and on the other hand are in communication with the grooves 5o. The fluidizing air can therefore through the passages 48 and 56 and the Flow up grooves 5o to fluidize the fuel bed.

It should be noted that the cups 54 on the tubes 22 are attached, while the plate 44 is not connected to the tubes connected is. The consequences of different expansion of the pipes gjj 22 and the plate 44, which would result from a firm connection, are thus avoided.

For introducing pulverized coal into the fuel bed, capped inlets 58 are provided (FIG. 4).

The additional advantages of the steam boiler 4o over those of the steam boiler 1o are that the lower collector tubes 24 with its relatively large Lie tal Linas se lie outside the fuel bed, so that they are very

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are not exposed to high temperatures within the fuel bed. The bends at the lower ends of the ito tubes 22, where they do not run vertically, are also located outside the fuel bed and therefore cannot overheat as a result of local inadequacies in the water cooling. Further, the air distribution plate 42 is provided with the type avoided that of the fuel bed precipitated ash passages blocked 48 and 56 of the air distribution plate 42 when the supply of the I ¹ IUID is ie approximately air is shut off, since most of ash particles are deposited on the upper surfaces of the bowls ^ A- from "

Although in the above description the .expressions "Water" and "steam" are used to mean these expressions Include other liquids and vapors as required.

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Claims (9)

l patent claims kit a fluidized fuel bed operated steam boiler, thereby. characterized in that a series of tube bundles (28) consisting of substantially vertical tubes is immersed in the fuel bed (14), extending between an upper and a lower collecting tube (24,26) and so side by side within the fuel bed (14) are arranged so that the xvohre (22) of the tube bundle (28) are distributed substantially uniformly over the ^ uschnittsflache of the fuel bed (14). W. 2. Steam boiler according to claim 1, characterized ge show that the inlet and outlet manifolds (24,26) with respect to the cross-sectional area of the fuel beds (14) run in a radial seal. 3. Steam boiler according to claim 2, characterized ge indicates that the fuel bed (14) is located in a cylindrical housing (12). 4 _e steam boiler according to one of the preceding claims, characterized in that the cross-section of the tube bundle (28) is approximately sector-shaped, the surface area being truncated inside and out. 5. Steam boiler according to one of the preceding claims. characterized in that all tube bundles (28) are made of plain tubes. 6. Steam boiler according to one of the claims 1 to 4, there characterized in that one or more tube bundles (28) from superheater or reheater tubes and the rest are made of split tubes. 20R06Q9 7 · Steam boiler according to one of the preceding claims, characterized in that the .fuel bed is located in a cylindrical inner housing (12), which is surrounded by a cylindrical outer housing (18) is, wherein the hanging duct (2o) present between the two housings is traversed by the fluidizing air. 8. Steam boiler according to one of the preceding iuis claims, characterized in that between the tube bundles (28) an open top, middle tube (;) 2) is provided, which is passed down through the fuel bed (14 ·) and as an overflow for removing particles of the fuel bed is used to maintain a constant level To maintain the fuel bed " 9. Steam boiler according to one of the preceding claims, characterized in that the lower header pipes (24) are arranged below an air distribution plate (42) which forms a floor for the fuel bed, the vertical tubes (22) through the air distribution plate (42) go through ο 1o. Steam boiler according to claim 9 »characterized in that that the air distribution plate (42) has a lower plate (44-) with circular openings (46) for contains the passage of the tubes (42), and that between the tubes (22) and the openings (46) annular passages (48) are provided for the fluidizing air that passes through inverted shells (54) or the like attached to the tubes (22) are covered in order to distribute the fluidizing air and prevent ash particles from falling into the annular passages (48) when the supply of fluidizing air is turned off will. 109826 / 105S