EP2220434B1 - Fluidized-bed furnace - Google Patents

Abstract

The invention relates to a fluidized-bed furnace (1) having a first stationary fluidized bed (6) to which fuels which are to be burnt can be fed. A second stationary fluidized bed (6') having immersed heating surfaces is assigned to the first fluidized bed (6). Heat output from the first fluidized bed (6) is obtained by surplus bed material (10) being fed automatically from the first fluidized bed (6) to the second fluidized bed (6'). Cooled bed material (21) from the second fluidized bed (6') can be recirculated to the first fluidized bed (6).

Description

The invention relates to a fluidized bed combustion.

Such fluidized bed combustion systems are used in various embodiments in order to burn fuels, in particular also waste materials, and thus to generate hot gas, which can be used for further processes.

Such fluidized bed combustors are typically integrated in a furnace and have at least one fluidized bed containing inert material, such as sand, limestone or ash, to which gas, in particular air, is supplied via a nozzle arrangement. Further, the furnace to be fired fuels are supplied via a feeder. By spraying with the nozzle assembly, the inert material is fluidized and mixed with the fuel to be fired. The ignition during the heating of the combustion process by means of a burner.

In general, a distinction is made between stationary and circulating fluidized bed firing. In a stationary fluidized bed combustion, the inert material stirred up by the nozzle arrangement remains in the fluidized bed. In contrast, in a circulating fluidized bed furnace, the inert material rises to the top of the furnace and is typically returned to the fluidized bed via cyclones and heat exchangers.

In a stationary fluidized bed combustion operation with or without Tauchheizflächen can be provided. In the case of operation without immersion heating surfaces, no heat emission from the fluidized bed is generally possible. By providing Although a heat discharge is possible from immersion heating surfaces, this is always dependent on the generation of hot gas, in particular on the generated hot gas heat.

In a circulating fluidized bed combustion is generally possible by the return of the fluidized material stirred up from the fluidized bed via heat exchangers an adjustable heat output. However, the disadvantage of circulating fluidized-bed furnaces is the high constructional complexity which arises, in particular, due to the return of the wound-up material. Also problematic are the high particle velocities within the fluidized bed combustion, which leads to an increased wear of components within the fluidized bed combustion and requires the high power requirement of the fan.

From the EP 0 262 105 a fluidized bed combustion is known which has a first fluidized bed and a laterally arranged next to this second fluidized bed. During operation, a transfer of bed material from the first fluidized bed to the second fluidized bed takes place. Via a feed line and an injector cooled bed material from the second fluidized bed is recycled to the first fluidized bed.

A corresponding fluidized bed furnace is from the US 5,060,599 A known.

The invention has for its object to provide a stationary fluidized bed with improved functionality.

To solve this problem, the features of claim 1 are provided. Advantageous embodiments and expedient developments of the invention are described in the subclaims.

The invention relates to a fluidized bed combustion with a first stationary fluidized bed, which are supplied to fuels to be fired. The first Fluidized bed is associated with a second stationary fluidized bed with Tauchheizflächen. A heat output from the first fluidized bed is obtained by excess bed material is automatically guided from the first fluidized bed to the second fluidized bed. In addition, cooled bed material is traceable to the first fluidized bed in the second fluidized bed. The fluidized bed furnace has an oven and is integrated in this. For discharging hot gas from the furnace, a cyclone disposed on a side wall of the furnace is provided, by means of which a circulating flow directed above the fluidized bed is generated in the interior of the furnace in a horizontal direction. A portion of the hot gases discharged from the furnace by means of the cyclone are returned to the furnace by means of a secondary air injector and / or mixed air or flue gas denitration gases are injected into the cyclone to enhance the circulating flow in the furnace.

With the stationary fluidized bed combustion according to the invention hot gas is generated on the one hand by the combustion of fuels. This hot gas can be used for different processes.

Furthermore, the heat discharged via the immersion heating surface from the first fluidized bed can also be used for external processes. Particularly advantageously, the immersion heating surfaces are formed by the surfaces of a heat exchanger arrangement. There, heat exchange fluids, in particular thermal oil, are heated by the heat discharged from the first fluidized bed.

An essential advantage of the invention is that an adjustable heat output is made possible for the fluidized bed combustion, whereby an optimal combustion process is obtained at different process parameters.

It is particularly advantageous that in the fluidized bed combustion according to the invention, the setting of the heat output can be completely independent of the setting of the temperature of the hot gas generated by the fluidized bed combustion.

The setting of the hot gas temperature is carried out by the specification of the air / fuel ratio, that is, the ratio of the air volume supplied to the first fluidized bed and the amount of fuel supplied. Irrespective of this, the heat release can be advantageously adjusted by adjusting the amount of bed material returned to the first fluidized bed. If there is an excess of bed material in the first fluidized bed, this flows over to the second fluidized bed and is cooled by the contact with the immersion heating surface. The more of the cooled bed material returned from the second fluidized bed to the first fluidized bed, the greater the excess bed material, the more bed material is passed from the first to the second fluidized bed. As a result, the greater the amount of heat released, the greater the amount of bed material returned to the first fluidized bed.

As a return unit, a pipe system with at least one nozzle is preferably provided, which is controlled by a control unit. About the control unit so the amount of recycled bedding material can be precisely specified. In particular, the quantity control of the recycled bed material can be integrated into a control loop, wherein the recycled amount of the bed material can be predetermined depending on the temperature of the guided in the heat exchangers thermal oil.

Since in the fluidized bed combustion according to the invention the heat removal via the second fluidized bed is independent of the setting of the hot gas temperature, which is predetermined by the specification of the air-fuel ratio, the efficiency of the fluidized bed combustion can be optimally adjusted within wide ranges.

Another essential advantage of the fluidized bed combustion according to the invention is that the first fluidized bed has a significantly lower height in comparison to known fluidized beds with immersion heating surfaces, since the immersion heating surfaces are displaced into the second fluidized bed. As a result, the required pressure of the combustion air, which increases linearly with the fluidized bed height, in the first fluidized bed of fluidized bed combustion according to the invention is considerably lower than in known fluidized beds with immersion heating surfaces integrated there. The low pressure required leads to a significant reduction of the required fan power and thus to a significant reduction in operating costs. Although a high pressure of the combustion air is required for the second fluidized bed, however, the second fluidized bed is considerably smaller than the first fluidized bed and the gas velocity is lower than in the first fluidized bed, so that overall a considerable saving effect remains.

Advantageously, the area of the second fluidized bed with the fluidized bed combustion is spatially separated from the furnace with the first fluidized bed. In addition, the gas velocities in the second fluidized bed are advantageously considerably lower than in the first fluidized bed. Thus takes place in the region of the second fluidized bed, where the heat exchanger assembly is, almost no combustion of fuel, so that there are no or almost no pollutants, whereby no or only a slight wear of the heat exchanger assembly is given by corrosion.

The heat exchanger arrangement forming the immersion heating surfaces is particularly advantageously designed as a modular, exchangeable unit, whereby the fluidized bed combustion according to the invention can be converted quickly and easily.

According to a particularly advantageous embodiment, the heat exchanger tubes of the heat exchanger assembly are mounted in holders which have irregular distances from one another.

Due to the arrangement of the holders for supporting the heat exchanger tubes at different distances from one another, vibrations of the heat exchanger tubes can be effectively damped during operation of the fluidized bed combustion. Due to the different distances of the brackets to each other namely vibrations of the heat exchanger tubes are avoided in the form of standing waves, whereby the life of the heat exchanger tubes is specifically increased.

According to a particularly advantageous embodiment of the invention, a nozzle arrangement is associated with the second fluidized bed, which allows the individual segments of the heat exchanger tubes between the individual brackets separately to apply air, whereby the Wärmeaustrag can be specifically controlled with the heat exchanger assembly.

The fluidized bed combustion according to the invention can generally be modified or extended so that instead of a first fluidized bed and a second fluidized bed, a plurality of first fluidized bed and / or a plurality of second fluidised bed can be provided, wherein different geometric arrangements of the fluidized bed are possible.

An essential aspect of the invention consists in that a cyclone arranged on a side wall of the furnace is provided for the outlet of hot gas from the furnace of the fluidized bed furnace, by means of which a circulating, circulating flow above the fluidized bed directed in the horizontal direction is generated in the interior of the furnace.

In this case, it is advantageous with respect to outlets at the top of the furnace that almost no bed material is whirled up by the fluidized beds due to the flow of the hot gas within the furnace in the horizontal direction.

Another advantage of this arrangement is that the cyclone can be arranged on the outside of the furnace, that is, in the furnace no corresponding components must be installed.

According to the invention, part of the hot gases discharged from the furnace by means of the cyclone are returned to the furnace by means of a secondary air injection device, so that the circulating flow in the furnace is intensified.

By the secondary air blowing dust particles that are contained in the outgoing with the cyclone from the furnace hot gas stream can be recycled into the oven, so that they are then burned safely in the oven.

A further variant of the invention provides that mixed air or gases for flue gas denitration are blown into the cyclone itself. The injection is preferably carried out so that the horizontal circulating flow is thereby enhanced in the oven. The injection of mixed air thereby promotes the afterburning of carbon monoxide and / or hydrocarbons contained in the hot gas stream. The blowing of gases with ammonia or urea for flue gas denitrification is particularly efficient in the area of the cyclone, since There by a strong Verwverwirbelung the necessary chemical reactions run particularly well.

Figur 1:

Ausführungsbeispiel der erfindungsgemäßen Wirbelschichtfeuerung.

Figur 2:

Wärmetauscheranordnung für die Wirbelschichtfeuerung gemäß Figur 1.

Figur 3:

Detaildarstellung der Wärmetauscheranordnung gemäß Figur 2.

Figur 4:

Außenansicht einer Variante der Wirbelschichtfeuerung gemäß Figur 1.

Figur 5:

Teildarstellung der Auslassvorrichtung der Wirbelschichtfeuerung gemäß Figur 4.

The invention will be explained below with reference to the drawings. Show it:

FIG. 1:

Embodiment of the fluidized bed combustion according to the invention.

FIG. 2:

Heat exchanger arrangement for fluidized bed combustion according to FIG. 1 ,

FIG. 3:

Detail representation of the heat exchanger assembly according to FIG. 2 ,

FIG. 4:

External view of a variant of the fluidized bed combustion according to FIG. 1 ,

FIG. 5:

Partial representation of the outlet device of the fluidized bed combustion according to FIG. 4 ,

FIG. 1 shows a schematic representation of an embodiment of the fluidized bed combustion according to the invention 1. The fluidized bed furnace 1 has a furnace 2, the masonry walls 3 are sealed on the outside with tiles. The furnace 2 has a main space 4, in which fuel can be introduced via inlets 5 to be fired. A first fluidized bed 6 is furthermore located in the main chamber 4 for forming a stationary fluidized bed furnace 1. This comprises a first nozzle arrangement 7 with a flat field of nozzles 8, preferably extending over the entire area of the main chamber 4, which are connected to the nozzle chambers 9 with gas. in particular air are applied. On the nozzles 8 of the nozzle assembly 7 is bed material 10 in the form of sand, ash or the like. The nozzle arrangement 7 is mounted on a frame 11. The term nozzle arrangement 7 is generally the entire air supply system for the fluidized bed 6, namely a nozzle box 9 for the introduction of air and a downstream arrangement of tubes 22, to which the individual nozzles 8 are arranged.

Due to the gas flow generated by the nozzle arrangement 7 in the first fluidized bed 6, mixing of the inert material with the fuel to be fired takes place. The combustion process is ignited by means arranged in the furnace 2 burners 12, such as gas burners or oil burners. By the combustion of the fuel hot gas is generated, which is discharged through an outlet 13 from the furnace 2. The hot gas is then available as an energy source for performing externally running processes. The temperature of the hot gas can be set by the air-fuel ratio, that is, the ratios of the amounts of air added through the nozzle assembly 7 and the amount of fuel supplied.

Particularly advantageously, the outlet in the form of an involute or the like is formed, through which a tangential air flow is generated in the region of the outlet, which causes conditionally contained by the centrifugal forces acting in the air flow particles are guided to the edge of the outlet. The outlet is designed so that the accumulating particles can fall back into the oven. As a result, a separation effect is obtained without additional design effort, which ensures that particles present in the outlet air flow are separated off. This effect can be exacerbated by the fact that in the fluidized bed combustion optionally required secondary air is flowed tangentially in the region of the furnace.

The furnace 2 has, in addition to the main space 4, an adjoining space 14, which is partially separated by a partition wall 15 extending vertically from the bottom of the furnace 2 in front of the main space 4. The ceiling of the furnace 2 in the area of the auxiliary space 14 is considerably lower than the ceiling of the furnace 2 in the region of the main space 4.

In this side room 14 is a second nozzle assembly 16 with an array of nozzles 17 and nozzle boxes 18, which are also mounted on a frame 19. This nozzle assembly 16 is lower than the nozzle assembly 7 in the main space 4. On the nozzle assembly 16 in the adjoining room 14, a heat exchanger assembly 20 is arranged, the elements form Tauchheizflächen. The nozzle arrangement 7 with the heat exchanger arrangement 20 serves to form a second fluidized bed 6 ', wherein this bed material 21 also comprises inert material.

How out FIG. 1 it is evident that the upper side of the nozzle arrangement 7 of the first fluidized bed 6 is at least approximately flush with the upper side of the heat exchanger arrangement 20, wherein the upper edge of the intermediate wall 15 lies approximately at the same height. Accordingly, the upper edges of the bed materials 10, 21 are at the same level.

If an excess of bed material 10 is present in the first fluidized bed 6, an overflow of the bed material 10 from the first fluidized bed 6 into the second fluidized bed 6 'takes place.

The height of the intermediate wall 15, is chosen so that a passage between the secondary 14 and main space 4 is given, through which the bed material 10 in the direction indicated by the arrow in FIG. 1 can flow over inclined direction.

Conversely, bed material 10, 21 can be supplied from the second fluidized bed 6 'to the first fluidized bed 6 by means of a recirculation unit. The recirculation unit in the present case comprises a tube 22 which leads from the underside of the second fluidized bed 6 'to the underside of the first fluidized bed 6. In the process, a vertically extending pipe section terminates at the second fluidized bed 6 'and is adjoined by a horizontal pipe section, from which finally a further vertical pipe section leads to the first fluidized bed 6. At the transition from this vertical pipe section to the horizontal pipe section is an injector nozzle 23, of a not shown Control unit is controlled. By means of the injector nozzle 23 controlled by the control unit, the amount of bed material 10 returned to the first fluidized bed 6 is predetermined.

FIG. 2 shows a detailed view of the structure of the heat exchanger assembly 20. The heat exchanger assembly 20 consists of an arrangement of heat exchanger tubes 24, in which thermal oil is performed as a heat transfer medium. The heat exchanger tubes 24 are mounted in plate-shaped holders 25a-d. On a front-side support 25d input and output ports 26 of the heat exchanger assembly 20 are provided. The planes of the brackets 25a-d are oriented perpendicular to the longitudinal directions of the heat exchanger tubes 24. The heat exchanger tubes 24 are fixed in position in bores of the holders 25a-d.

Excess bed material 10 from the first fluidized bed 6 flows into the second fluidized bed 6 'and comes into contact with the immersion heating surfaces formed by the surfaces of the heat exchanger tubes 24 of the heat exchanger arrangement 20, see above that this is cooled. Cooled bed material 21 from the second fluidized bed 6 'is returned to the first fluidized bed 6 via the recirculation unit. The more bed material 21 is recycled via the recirculation unit, the more bed material 10 flows out of the first fluidized bed 6 into the second fluidized bed 6 ', the greater is the heat output from the first fluidized bed 6. The amount of recirculated bed material 21 can be arbitrary via the control unit be specified. The return can be done continuously or temporally discrete. Particularly advantageous is a controlled return as a function of the temperature of the thermal oil in the heat exchanger assembly 20th

By transferring the bed material 10 from the first fluidized bed 6 into the second fluidized bed 6 ', the thermal oil in the heat exchanger arrangement 20 is heated. The heat generated in this way can be used for external processes.

Since the return of the bed material 10, 21 via the feedback unit by the control unit is independent of the combustion process in the furnace 2, in particular independent of the specification of the air-fuel mixture, the removal of heat via the heat exchanger assembly 20 can be carried out independently of the combustion process, that is in particular without reducing the efficiency of the combustion process.

The gas velocities in the first fluidized bed 6 are significantly higher than the gas velocities in the second fluidized bed 6 ', which is achieved by the amount of air per unit area in the nozzle assembly 7 of the first fluidized bed 6 is considerably larger than in the nozzle assembly 16 of the second fluidized bed 6' , Typically, the gas velocities in the first fluidized bed 6 are in the range of 1 to 3 m / s and in the second fluidized bed 6 'in the range of 0.5 to 1.5 m / s.

Characterized in that the heat exchanger tubes 24 of the heat exchanger assembly 20 are thus exposed only to particles with low flow velocity, they are subjected to only little wear. This effect is exacerbated by the fact that only in the main room 4 with the first fluidized bed 6, a significant combustion of fuel, but not in the adjoining room 14 with the second fluidized bed 6 ', so there are significantly less pollutants. In order nevertheless to avoid damage by corrosion or the like, the heat exchanger tubes 24 preferably have protective coatings, in particular Inconel coatings.

How out FIG. 2 As can be seen, the middle brackets 25a-d of the heat exchanger assembly 20 are arranged asymmetrically, so that they share in the longitudinal direction of the heat exchanger assembly 20 extending heat exchanger tubes 24 into segments of different lengths. Here, the brackets 25a-d are arranged in the present case so that the lengths of the first segments of the heat exchanger tubes 24 between the brackets 25a and 25b about 15% of the total length of the heat exchanger tubes 24 between the brackets 25a and 25d, the lengths of second segments of the heat exchanger tubes 24 between the brackets 25b and 25c are about 35% of the total length and the lengths of the third segments are about 50% of the total length. As a result of these asymmetrical arrangements of the holders 25a-d, vibrations of the heat exchanger tubes 24 are reduced with high efficiency, since standing waves on the heat exchanger tubes 24 can not form due to this arrangement of the holders 25a-d.

The nozzle assembly 16 is formed so that the individual segments of the heat exchanger tubes 24 are selectively acted upon with air from the nozzle assembly 16. Thereby, the Wärmeaustrag can be adjusted with the heat exchanger assembly 20 in a simple manner.

FIG. 3 shows a detailed view of the heat exchanger assembly 20 according to FIG. 2 , The heat exchanger tubes 24 are in the form of several, in the present case of three individual strands 24a-c formed, each of which forms a multiple between the front-side brackets 25a and 25d back and forth piping arrangements. In FIG. 3 For the sake of clarity, the single strands are shown pulled apart. On the input side and output side control valves 27a-c, 28a-c are provided on the individual strands to form the input and output ports.

The individual strands are individually monitored by the control unit, so that the temperature difference of the thermal oil between input and output and the flow rates of thermal oil are the same for all single strands. To determine the temperature differences, first temperature sensors 29a-c are provided on the input side of the individual strands, and second temperature sensors 30a-c are provided on the output side. For flow measurement, the aperture 31 a-c are provided on the output side.

FIG. 4 shows an external view of a variant of the fluidized bed combustion 1 according to FIG. 1 , The components of the fluidized bed 1 within the Furnace 2, in particular the formation of the first fluidized bed 6 and the second fluidized bed 6 'with the associated Tauchheizflächen correspond to the embodiment according to FIG. 1 , In the main area 2 a of the furnace 2 is the first fluidized bed 6, while in the subsequent, smaller side area 2 b of the furnace 2, the second fluidized bed 6 'is located.

The embodiment according to FIG. 4 differs from the fluidized bed 1 according to FIG. 1 only in that instead of the outlet 13 at the top of the furnace 2 on the outside of a side wall of the furnace 2, a laterally arranged outlet device is provided which has a cyclone 27 as an essential part. Between the side wall and the cyclone 27 is a funnel-shaped hollow body 28th FIG. 5 shows a perspective view of the hollow body 28 and the cyclone 27 from the interior of the furnace 2 from. As a connection for the outlet device, a hollow cylindrical collar plate 29 is inserted into an opening in the side wall of the furnace 2.

By the cyclone 27, a spiral gas flow is generated, which continues into the interior of the furnace 2. This circulating flow is directed along the longitudinal side of the cyclone 27 and thus in the horizontal direction, wherein this flow is above the fluidized bed 6, 6 '. The horizontal flow prevents unwanted fluidization of bed material on the fluidized beds 6, 6 '. The circular flow is enhanced by the shape of the furnace 2 with a rounded, semi-cylindrical roof.

In order to at least partially lead the dust particles back into the furnace 2 and then burn them there in a second combustion process, a Sekundärlufteinblasvorrichtung is provided. This Sekundärlufteinblasvorrichtung has at the lower end of the funnel-shaped hollow body an injector 30, that is, a jet nozzle. From there pipelines 31 back in the furnace 2. In the present case, the pipes 31 open directly below the inlets 5 for the fuel to be fired.

The hot gas contained in the furnace 2 is passed through the opening in the cyclone 27 and discharged from there. Dust particles contained in the hot gas therefore migrate outwards due to the centrifugal forces of the flow, are collected in the funnel-shaped hollow body 28 and returned to the furnace 2 via the injector 30 and then via the pipelines.

In the embodiment according to FIG. 4 are also provided in the cyclone 27 leading leads 32. Via these supply lines 32 gases in the form of mixed air and / or ammonia or urea are blown. By blowing in mixed air, an afterburning of carbon monoxide and hydrocarbons in the hot gas to be carried out is achieved. By blowing in ammonia, urea or the like a Rauchgasentstickung is achieved. The tangential blowing direction of the gases into the cyclone 27 further increases the circular flow generated there.

LIST OF REFERENCE NUMBERS

(1)

fluidised bed combustion

(2)

oven

(2a)

main area

(2 B)

In addition to area

(3)

wall

(4)

main room

(5)

inlet

(6)

fluidized bed

(6 ')

fluidized bed

(7)

nozzle assembly

(8th)

jet

(9)

nozzle box

(10)

bed material

(11)

frame

(12)

burner

(13)

outlet

(14)

Outbuildings

(15)

partition

(16)

second nozzle arrangement

(17)

jet

(18)

nozzle box

(19)

frame

(20)

The heat exchanger assembly

(21)

bed material

(22)

pipe

(23)

injector nozzle

(24)

heat exchanger tube

(25a-d)

bracket

(26)

connection

(27)

cyclone

(27a-c)

control valves

(28)

hollow body

(28a-c)

control valves

(29)

collar sheet

(29a-c)

temperature sensors

(30)

injector

(30a-c)

temperature sensors

(31)

piping

(31a-c)

dazzle

(32)

supply

Claims (13)

1. Fluidised-bed furnace (1) with a first stationary fluidised bed (6), to which fuels to be fired can be supplied, wherein a second stationary fluidised bed (6') with immersion heating surfaces is associated with the first fluidised bed (6) and heat output from the first fluidised bed (6) is obtained in that excess bed material (10) is automatically led from the first fluidised bed (6) to the second fluidised bed (6'), and wherein bed material (21) cooled in the second fluidised bed (6') can be fed back to the first fluidised bed (6), wherein the fluidised-bed furnace (1) comprises an oven (2) and is integrated in this, and for the delivery (13) of hot gas from the oven (2) a cyclone (27), by means of which in the interior of the oven (2) a circulating flow directed in horizontal direction is generated above the fluidised beds (6, 6'), is provided at a side wall of the oven (2), characterised in that a part of the hot gas led out of the oven (2) by means of the cyclone (27) is fed back by means of a secondary air injection device into the oven (2) so that the circulating flow in the oven (2) is reinforced and/or that mixed air or gases for flue-gas nitrogen oxide removal is or are so injected into the cyclone (27) that the circulating flow in the oven (2) is reinforced.
2. Fluidised-bed furnace according to claim 1, characterised in that the immersion heating surfaces are formed by a heat exchange arrangement (20), wherein a heat exchange liquid is heated in the heat exchange arrangement (20), and that externally useable process heat is generated by heating of the heat exchange liquid.
3. Fluidised-bed furnace according to claim 2, characterised in that the heat exchange arrangement (20) comprises an arrangement of heat exchange pipes (24) mounted in a plurality of mounts (25a-d), wherein the segments of the heat exchange pipes (24) are of different sizes between different adjacent mounts (25a-d), wherein the mounts (25a-d) are formed by plates which are arranged one behind the other and at different mutual spacings in parallelly extending planes in the longitudinal direction of the heat exchange pipes (24) and wherein the heat exchange pipes (24) are mounted in bores of the mounts (25a-d).
4. Fluidised-bed furnace according to one of claims 2 and 3, characterised in that the heat exchange pipes (24) of the heat exchange arrangement (20) form a plurality of individual runs which are individually monitored by monitoring units associated therewith, wherein the temperature difference between an inflowing and outflowing heat exchange liquid as well as the throughflow quantity of the heat exchange liquid are monitored by each monitoring unit for each individual run and wherein the temperature differences and throughflow quantities of the individual runs are respectively set to the same values by means of, in particular, the monitoring units.
5. Fluidised-bed furnace according to any one of claims 2 to 4, characterised in that the heat exchange arrangement (20) forms a modular, exchangeable unit.
6. Fluidised-bed furnace according to any one of claims 1 to 5, characterised in that the first fluidised bed (6) and the second fluidised bed (6') each comprise a respective nozzle arrangement (7, 16) able to be acted on by air, wherein the regions between two mounts (25a-d) of the heat exchange arrangement (20) can be selectively acted on by air by way of the nozzle arrangement (16).
7. Fluidised-bed furnace according to claim 6, characterised in that the nozzle arrangement (16) of the second fluidised bed (6') is disposed lower by comparison with the nozzle arrangement (7) of the first fluidised bed (6), that the heat exchange arrangement (20) is arranged above the nozzle arrangement (16) of the second fluidised bed (6') and that the upper sides of the fluidised beds (6, 6') mutually adjoin so that excess bed material (10) of the first fluidised bed (6) runs over onto the second fluidised bed (6').
8. Fluidised-bed furnace according to claims 7, characterised in that the two fluidised beds (6, 6') are separated by a wall (15), wherein the height of the wall (15) is so dimensioned that the excess bed material (10) can overflow from the first fluidised bed (6) to the second fluidised bed (6') via the upper edge.
9. Fluidised-bed furnace according to any one of claims 1 to 8, characterised in that a pipe system with at least one nozzle is provided as return unit for return of cooled bed material (21) from the second fluidised bed (6') to the first fluidised bed (6), wherein the nozzle is controlled by a control unit, wherein the heat delivery from the first fluidised bed (6) is regulable in the control unit by a quantity control of the bed material (21) returned by means of the nozzle and wherein the regulation in the control unit is carried out in dependence on the temperature of the heat exchange liquid in the heat exchange arrangement (20).
10. Fluidised-bed furnace according to any one of claims 2 to 9, characterised in that the heat exchange liquid is formed by thermal oil.
11. Fluidised-bed furnace according to any one of claims 1 to 9, characterised in that hot gas having a temperature regulable independently of the heat delivery from the second fluidised bed (6') is generated in the furnace, wherein for presetting the temperature of the hot gas the ratio of the air fed by way of the nozzle arrangement (7) of the first fluidised bed (6) and the supplied fuels is settable.
12. Fluidised-bed furnace according to any one of claims 1 to 11, characterised in that the flow speed in the second fluidised bed (6') is significantly smaller than the flow speed in the first fluidised bed (6).
13. Fluidised-bed furnace according to any one of claims 1 to 12, characterised in that this comprises a plurality of first fluidised beds (6) and/or a plurality of second fluidised beds (6').

Images