EP2715229A1

EP2715229A1 - Steam generator

Info

Publication number: EP2715229A1
Application number: EP12724986.0A
Authority: EP
Inventors: Klaus VÖLKERER; Willibald Eidler; Arno Past; Josef Koglbauer
Original assignee: Individual
Current assignee: Vep Umwelttechnik - Neumot - Produktions- und Vert
Priority date: 2011-05-30
Filing date: 2012-05-30
Publication date: 2014-04-09
Anticipated expiration: 2032-05-30
Also published as: EP2715229B1; PL2715229T3; AT511485B1; SI2715229T1; HRP20151149T1; DK2715229T3; HUE026453T2; AT511485A1; WO2012163961A1

Abstract

The invention relates to a steam generator, comprising a combustion chamber (1), a flue gas duct (10), and a boiler assembly (2). The boiler assembly (2) has a plurality of individual, identically designed steam boilers (3) for obtaining an appropriate amount of steam. The steam boilers have riser pipes (4) that are guided through the combustion chamber (1). The steam boilers (3) can optionally have a respective pipe array, which comprises at least the riser pipe (4), a steam discharge pipe (5), a down pipe (6), and a connecting pipe (7) that leads from the down pipe (6) to the riser pipe (4).

Description

steam generator

The subject invention relates to a steam generator with a combustion chamber, at least one flue gas duct and a boiler assembly.

The production of steam has been an essential necessity of many industrial installations since the beginning of the industrial revolution. Despite the many years of experience in dealing with steam generators, their operation is still risky, since it at

Carelessness or technical failure can lead to dangerous steam explosions. Therefore, the installation, operation and maintenance of steam generators are subject to strict regulatory requirements, such as in Austria

"Pressure Equipment Surveillance Ordinance" (DGÜW-V), the "Installation and Operation of Steam Boiler Ordinance" (ABV) and the "Steam Boiler Operating Act" (DKBG).

The risk potential of a steam boiler plant is mainly dependent on the volume of the pressure vessels and the maximum operating pressure, whereby the plants can be classified according to certain characteristics, such as the pressure content product (product of operating pressure times volume) in different hazard classes.

For steam boilers, pressure vessels or pipelines with a high risk potential, comprehensive and costly provisions must be observed for the first company audit, regular audits, type of monitoring, revision periods and monitoring measures (measures within the framework of periodic inspections and checks) as well as their documentation.

Systems with a low risk potential are exempted from these strict regulations and have, among other things, the advantage that, for example, the monitoring can be carried out by the operator himself. Pressure vessels with a low risk potential include overheating s endangered steam boilers or pressure vessels susceptible to overheating, the pressure-content product of which is less than 200 [bar x 1] or, if made of pipes with

Nominal diameters up to and including DN 32, the pressure content of which is less than 350 [bar x 1]. These include, for example, so-called "fast steam generators".

However, quick steam generators deliver only small amounts of steam of mostly low quality and are therefore unsuitable for many applications. There is therefore a need for cost-effective steam generators with a low risk potential, which can also produce large quantities of high-quality steam. This would significantly reduce the cost of steam generation with the greatest possible reliability.

The subject invention solves this problem by a steam generator of the type mentioned, in which the boiler assembly has a plurality of individual, identically designed steam boilers, which have risers, which are guided through the combustion chamber. The individual steam boilers can thereby be dimensioned relatively small, so that they have only a low risk potential and also meet the corresponding legal safety criteria. The amount of steam that can be generated is not increased by an increase in boiler volume and maximum pressure, but is determined by the number of steam boilers that are operated via the combustion chamber. Depending on requirements, the steam boilers can be designed as a natural circulation, forced circulation or forced circulation boiler. Forced-circulation boilers may, for example, have helical risers which are guided through the combustion chamber.

Advantageously, the steam boiler can each have a pipe construction, which at least the riser, a steam ablas srohr, a downpipe and a leading from this to the riser connecting pipe. Such a media circulation effecting pipe construction is simple and inexpensive to manufacture, with standardized

Pipe elements can be used. By choosing the preferably standardized tubes, a high compressive strength of the tube construction can be achieved in a simple manner.

In a preferred embodiment of the invention, the steam boilers can have a horizontally arranged evaporator tube at the operating level of the water level. As a result, the water surface at which the generated steam can escape from the water, significantly increased. The achievable steam quality can be improved.

An advantageous embodiment of the invention may provide that the tube axes of a steam boiler are arranged substantially in the same, preferably vertical plane. Due to the flat construction achieved thereby, it is possible to arrange several steam generators in a small space next to each other, so that the space available in the combustion chamber can be optimally utilized. Preferably, in one embodiment of the invention, a heat exchanger for feeding water may be arranged in the flue gas duct. This improves the

Energy efficiency of the system.

In this case, the heat exchanger advantageously comprises tubes whose tube axes are arranged substantially in the same plane as the tube axes of the boiler. This allows an extremely compact construction of steam boiler and heat exchangers, wherein the tubes of the heat exchanger, for example, can be arranged within a frame formed by riser, steam outlet pipe, downpipe and connecting pipe. Several flat juxtaposed heat exchanger of several juxtaposed, flat steam boilers can be arranged in an advantageous manner in the same flue gas duct. Baffles in the flue gas duct can increase the flow path of the flue gas in the heat exchanger and thus improve the heat transfer.

Advantageously, each steam boiler may be constructed of tubes up to and including a maximum of DN 32, wherein the pressure-content product (p x V) may be less than 350 [bar x 1]. As a result, the steam boiler has only a low risk potential and it can comply with the provisions that are prescribed by law for systems with low risk potential. National safety regulations may set different limits in different states. It lies however in the abilities of a

One skilled in the art, the teachings of the invention also apply to other standards or statutory provisions advantageous.

In a further advantageous embodiment of the invention, for cooling the

Combustion chamber walls may be provided at least one further steam boiler, the riser tubes are arranged in the region of the combustion chamber walls. The risers such Brennraumwand- steam boiler, for example, in the areas where no risers of

the former identically constructed steam boiler are provided, like a cage around the

Combustion chamber wall be arranged so that the wall is cooled in all areas and the

Steam generation is used. This improves the steam yield and energy efficiency of the system while providing cooling of the combustion chamber walls.

Preferably, the steam extraction lines leading away from the respective steam extraction connections of the steam boiler can open in a steam manifold. This is possible because the steam manifold, out of safety considerations, is no longer to count the volume of the steam boiler. Several steam boilers, whose steam is introduced into a common steam manifold, are therefore for the interpretation of the

Safety criteria not to be considered as total volume, but individually. Thus, it is possible to produce large amounts of steam with a steam generator according to the invention, which in terms of safety and the legal operating conditions a

Fast steam generator corresponds.

On the other hand, the steam extraction lines leading away from the respective steam extraction connections of the steam boilers may optionally have one

Steam jet compressor, each opening into a arranged in the combustion chamber superheater pipe. Steam superheating is beneficial, for example, for feeding steam engines or turbines. The steam generator according to the invention can be used advantageously for the operation of a power plant, such as for power generation from biomass or gas, even in relatively small scale. The steam jet compressors can be used to feed multi-stage steam engines, for example a turbine or a multi-stage steam engine

Axial piston motor, are used, is derived from the engine, relaxed exhaust steam of a stage in the steam jet compressor with the steam supplied by the steam boiler fresh steam to the desired level and in the superheater is brought to the required temperature for the next stage.

The individual superheater tubes can advantageously be helically wound in the region of the combustion chamber and arranged in the manner of a cylinder. As a result, the available space in the combustion chamber can be used optimally.

The invention will now be described by way of example with reference to the accompanying drawings, in which:

1 is a fiction, contemporary boiler assembly in perspective view,

2 and 3, the boiler assembly of FIG. 1 in a side view and

4 shows the same boiler assembly in a plan view;

Fig. 5 shows a similar-shaped steam boiler in a side view and

FIG. 6 shows the steam boiler of FIG. 5 in a perspective view; FIG.

7 shows a combustion chamber wall steam boiler in a perspective view;

Fig. 8 shows a further advantageous embodiment of the fiction, contemporary boiler assembly in which the steam extraction lines open in a vapor manifold, and , Fig. 9 shows the boiler assembly of Fig. 8 with the combustion chamber wall and the flue gas ducts.

In the following description, like components are each the same

Provided with reference numerals. If necessary for the description, the

Reference numerals of components that are multiple in a figure, by

Lowercase letters added.

Fig. 1 to 4 show a first fiction, contemporary embodiment of the steam generator in perspective view (Fig. 1), in two side views (Figures 2 and 3) and a plan view (Fig. 4). For better visibility of the individual components has been dispensed with a representation of the walls of the combustion chamber and the flue gas duct. The figures thus show primarily the boiler assembly 2 of the invention.

The individual components are mounted on a frame 18, wherein the combustion chamber 1 is located in the middle of the substantially symmetrical construction. On both sides five steam boilers are arranged, wherein for the sake of clarity in Fig. 1, only the steam boilers 3a to 3e of the right side are provided with reference numerals.

The construction of the individual steam boiler 3 will now be explained in more detail with reference to FIGS. 5 and 6. The illustrated steam boiler 3 is a natural circulation boiler, wherein the

Feed water is introduced via a feedwater supply 23 and preheated via a heat exchanger 11, which is located in the flue gas duct 10. Opposite the

Feedwater supply 23, a pressure measuring device 19 is arranged to control the operating pressure. The flue gas channel 10 is shown in Fig. 5 only schematically by dashed lines, wherein in the interior of the flue gas duct 10 a plurality of baffles 20 are arranged, which extend the path of the flue gas in the region of the heat exchanger 11. The baffles 20 are arranged obliquely in Fig. 5, but they can also transversely to the tubes of the

Heat exchanger 11 run when this is structurally easier to implement. The

Feedwater rises in the tubes of the heat exchanger 11 high, is preheated while cooling the flue gases and is in the upper part of the riser 4 the

Water cycle added. The riser 4 is arranged in the combustion chamber 1 and extends therein vertically along a combustion chamber wall. (A corresponding combustion chamber wall is shown, for example, in the embodiment shown in FIG. 9). However, the riser 4 may also have an oblique or tortuous course, unless this affects the arrangement of the other steam boiler. In the upper part of the riser 4 is located in the combustion chamber 1, a vent opening 21 through which the flue gases from the combustion chamber 1 enter the flue gas duct 10. The supply line 22 for the feed water from the

Heat exchanger 11 is located just above this exhaust port 21st

Above the feed line 22, the riser pipe 4 branches into a horizontally arranged evaporator tube 9 and a vapor discharge pipe 5 lying parallel above it. In operation, the water level 8 is approximately in the middle of the evaporator tube 9, so that the water surface available for evaporation is maximized , This prevents vapor bubbles, which may form further below in the riser pipe 4, from rising up a "water plug" up to the steam extraction port 14, which would affect the quality and dryness of the vapor being removed Exiting steam in a wide range from the water and either rise through the extension of the riser 4 or via an additional Ausvampfrohr 24 in the steam outlet pipe 5. The Dampfentnahme- connection 14, where the steam to a Dampfentnahmeleitung 15 (Fig. 1 to 4) is discharged, is located on the steam outlet pipe 5 at the uppermost point of the boiler 3. Further, the steam outlet pipe 5 is a

Safety valve 25 is arranged.

The steam outlet pipe 5 opens into a vertical level pipe 28, at the upper end of a level sensor 26 is used, via which the water level can be controlled. In addition, a sight glass 27 is arranged for visual inspection on the level pipe 28 in the height of the operating water level 8. The lower end of the fill level pipe 28 opens into a downpipe 6, which extends from the combustion chamber remote end of the evaporator tube 9 down. The water cycle is closed by a connecting pipe 7, which enters the combustion chamber 1 in the lower region and opens into the riser pipe 4. At the

Connecting pipe 7 is further arranged in the lowest area of the boiler, a drain valve 29, via which the system can be emptied.

In order to provide a forced circulation instead of a natural circulation, only a circulation pump would have to be additionally installed, for example in the region of the downpipe 6 or the connecting pipe 7. This can be implemented constructively by a person skilled in the art without further ado.

To operate the invention with forced-circulation boilers, some further structural changes would be required, but also the skill of a To those of ordinary skill in the art. A forced circulation boiler would not contain a downpipe 6, but the preheated in the heat exchanger 11 feed water would be fed directly to the riser 4 via a connecting pipe.

The riser 4 can be extended by being guided, for example, helically or meandering in the combustion chamber 1. This can be advantageous, above all, for steam generators without preheating or for forced circulation boilers. The winding risers of several

Steam generators could form a cylindrical shape superimposed in the combustion chamber in the form of a multiple helix, whereby a uniform heating of all riser tubes could be achieved. It is also not mandatory that the riser pipes must be vertical and straight. Rather, for example, meandering pipes or diagonal running through the combustion chamber 1 pipes can be used as risers, as long as this is compatible with the arrangement of the other steam boiler.

As can be clearly seen in Fig. 6, all the tubes of the boiler 3 are arranged in a common vertical plane in the illustrated embodiment, so that in the

Substantially rectangular steam boiler 3 has a flat shape. This makes it possible in a simple manner, closely juxtaposed several similar steam boiler, as can be seen for example in Fig. 1, in which on both sides of the combustion chamber five steam boilers 3a-3e are arranged flat side by side.

The illustrated embodiment of the steam boiler is constructed exclusively from standardized pipes, for example with a nominal diameter of DN 32 and DN 25, so that within the meaning of the Austrian Pressure Equipment Surveillance Ordinance (DGÜW-V) a steam boiler consisting of such pipes can only be used from a pressure content of more than 350 bar x 1] represents a steam boiler with a high risk potential. When using larger

Pipe diameter already a pressure content product of over 200 [bar x 1] would cause a high risk potential of the boiler. In the embodiment shown in FIGS. 5 and 6, with a maximum height of about 190-200 cm and a maximum width of about 70-90 cm, a steam boiler volume of about 10 liters can be achieved by suitable dimensioning of the tubes. At a maximum operating pressure of 32 bar, this results in a pressure-content product of approx. 320 [bar x 1], so that the steam boiler according to DGÜW-V has a low hazard potential. Referring again to FIGS. 1 to 4, it can be seen that the ten risers 4 of the steam boiler 3 are arranged in a lattice-like manner on two opposite sides of the combustion chamber 1. In order to use the remaining side surfaces of the combustion chamber to generate steam and to cool the fireclay panel of the combustion chamber walls, two more steam boilers, the combustion chamber wall steam boiler 12, provided, the riser tubes 13 extend bar-like vertically to the side surfaces of the combustion chamber wall and in addition to the additional steam yield cooling cause the combustion chamber walls.

In Fig. 7, a combustion chamber wall steam boiler 12 is shown removed. Of the

Combustor wall steam boiler 12 has a plurality of parallel risers 13 which are secured to the frame 18 and are supplied with feed water via distribution pipes 30. The distribution pipes 30 are in turn fed via a supply pipe 31, on which a feedwater supply 23 and a pressure measuring device 19 are provided. Furthermore, the combustion chamber wall steam boiler 12 has a vertical level pipe 28 with a

Level sensor 26 and a sight glass 27 on. The sight glass 27 is disposed at the level of the service water level. At its upper end, the riser pipes 13 open into collecting pipes 32, via which the steam is discharged into a steam outlet pipe 5, at which a safety valve 25 and a steam extraction connection 14 are located.

The risers 13 form two groups, which are each arranged in a corner of the combustion chamber wall. The first group of rising pipes 13a-13g are each of equal length and extend essentially over the entire height of the combustion chamber wall. The

Risers 13h-13o of the second group are of different lengths, since at the

Brennraumvorderseite a room for a combustion opening 34 must be kept free. The risers 13h to 131 extend substantially over the entire height of

On the other hand, the combustion chamber wall, the riser ducts 13m to 13o, extend between an intermediate tube 35 located above the firing opening, which is connected to the two riser ducts 13k and 131, and one of the upper manifolds 32. Both groups extend on the combustion chamber front and rear walls, respectively Substantially up to half of the combustion chamber, from where the corresponding risers of the opposite

Combustor wall steam boiler 12 begin. Thus, essentially the entire

Combustion chamber wall used for steam generation.

The two riser groups of a combustion chamber wall steam boiler 12 are spaced apart, wherein in the gap between the risers 4 of the five similar trained steam boiler 3 run. On the frame 18 a plurality of receptacles 33 are provided for the risers 4 of the five similarly designed steam boilers 3.

The steam generator according to the invention shown in Fig. 1 to 4 is able to supply superheated steam in twelve different pressure levels a consumer. As a consumer, for example, a multi-stage turbine or a multi-stage Achsialkolbenmotor be driven. To generate the different steam qualities

cascaded steam jet compressor 16, which are arranged above the combustion chamber. Each steam jet compressor 16 is fed via a steam extraction line 15 with the steam generated in one of the twelve steam boilers 3, 12, with the steam in each

Steam boiler produced steam of substantially the same quality, for example, a pressure of 32 bar and a temperature of about 240 ° C (saturated steam). The second input of the steam jet compressor 16 is charged with the relaxed in the subsequent stage steam. This partially expanded steam is then in the

Steam jet compressor 16 is treated with the live steam and introduced into a superheater tube 17 in which the steam overheats to, for example, about 420 ° C and the

downstream working stage is supplied. As can be seen in FIGS. 1 to 4, the superheater tubes 17 of the various stages are arranged helically parallel one above the other so that the entirety of the superheater tubes form a cylindrical shape.

The illustrated embodiment may generate steam at twelve different pressure levels. However, it is also easily possible to summarize several stages and to produce 16 four different pressure levels, for example, each with three parallel interconnected steam jet compressors. Several steam extraction lines 15 could also be fed together to a steam jet compressor 16. For example, four steam extraction lines could be combined in one of three steam jet compressors to generate three pressure levels. In cases where no different steam levels are needed, the steam jet compressor could be completely dispensed with, the steam of the

Steam extraction lines 15 would be introduced directly into the superheater tubes 17. It is also possible to generate different vapor pressures by varying the pressure in the individual steam boilers. The steam generator according to the invention can thus be flexibly adapted to different needs. FIG. 8 shows a further embodiment of the steam generator according to the invention, which does not have a superheater. This embodiment is advantageous for all applications in which superheated saturated steam is not required, for example for steam cleaning or for temperature control in the chemical industry and the food industry (eg in breweries). As can be seen in Fig. 8, the individual steam extraction lines 15 of the twelve steam boilers 3, 12 are combined to form a single vapor manifold 36 and fed to the consumer. The other components shown in Fig. 8 correspond to

Essentially the embodiment shown in Fig. 1, so that no further detailed explanation is required.

Fig. 9 shows the steam generator of Fig. 8, but in Fig. 9, the combustion chamber walls 37 and the flue gas duct 10 are shown. In the combustion chamber walls 37 is a

Furnace opening 34 is provided, in which the burner is used. The lateral opening in the flue gas duct 10 is closed by a simple bolted cover.

List of reference numbers:

Combustion chamber 1

Boiler assembly 2

Steam boiler 3

Riser 4

Steam outlet pipe 5

Downpipe 6

Connecting pipe 7

Water level 8

Evaporator tube 9

Flue gas duct 10

Heat exchanger 11

Combustion chamber steam boiler 12

Risers 13 of the combustion chamber wall steam boiler

Steam extraction connection 14

Steam extraction lines 15

Steam jet compressor 16

Superheater tube 17

Frame 18

Pressure measuring device 19

Baffles 20

Discharge opening 21

Supply line 22

Feedwater supply 23

Evaporating pipe 24

Safety valve 25

Level sensor 26

Sight glass 27

Level tube 28

Drain valve 29

Distribution pipes 30

Supply pipe 31

Headers 32

Shots 33

Burner opening 34

Intermediate pipe 35

Steam manifold 36

Combustion chamber walls 37

Claims

claims

1. Steam generator with a combustion chamber (1), at least one flue gas duct (10) and a boiler assembly (2), characterized in that the boiler assembly (2) has a plurality of individual, similarly formed steam boilers (3), which risers (4) have, which are passed through the combustion chamber (1).

2. Steam generator according to claim 1, characterized in that the

Steam boiler (3) each having a tubular construction, which at least the riser (4), a steam outlet pipe (5), a downpipe (6) and from this to the riser pipe (4) leading connecting pipe (7).

3. Steam generator according to claim 2, characterized in that the

Steam boiler (3) at the operating level of the water level (8) have a horizontally arranged evaporator tube (9).

4. Steam generator according to claim 2 or 3, characterized in that the tube axes of a steam boiler (3) are arranged substantially in the same, preferably vertical plane.

5. Steam generator according to one of the preceding claims, characterized

characterized in that in the flue gas duct (10) has a heat exchanger (11) for

Speisewas servorwärmung is arranged.

6. Steam generator according to claim 5, characterized in that the

Heat exchanger (11) has tubes whose tube axes are arranged substantially in the same plane as the tube axes of the steam boiler (3).

7. Steam generator according to one of the preceding claims, characterized

characterized in that each boiler is made up of pipes up to and including a maximum of DN 32, the pressure content product (pxV) being less than 350 [bar x 1].

8. Steam generator according to one of the preceding claims, characterized in that for cooling the combustion chamber walls (37) at least one further

Steam boiler (12) is provided, the riser tubes (13) are arranged in the region of the combustion chamber walls.

9. Steam generator according to one of the preceding claims, characterized

characterized in that the of the respective Dampfentnahme- connections (14) of the

Steam boiler (3, 12) wegführenden steam extraction lines (15) in one

Steam manifold (36) open.

10. Steam generator according to one of claims 1 to 8, characterized in that the of the respective Dampfentnahme- connections (14) of the steam boiler (3, 12)

wegführenden steam extraction lines (15), optionally via one each

Steam jet compressor (16), each in a arranged in the combustion chamber superheater pipe (17) open.

11. Steam generator according to claim 10, characterized in that the individual superheater tubes (16) in the region of the combustion chamber helically wound and arranged in a cylinder-like manner.