EP2912374B1 - Method for producing steam - Google Patents

Description

The invention relates to a method for generating water vapor, are burned in the hydrogen and oxygen with the addition of liquid water in a combustion chamber. Furthermore, the invention relates to a device for carrying out this method and a submarine with such a device.

It is well known to generate water vapor by combustion of hydrogen and oxygen. It is also part of the state of the art to introduce water outside the actual combustion zone and thus vaporize it in order to generate additional water vapor into the combustion chamber in which the combustion of the hydrogen with the oxygen takes place.

The adiabatic flame temperature is comparatively high in the stoichiometric combustion of hydrogen and oxygen. This can lead to a part of the water vapor generated during combustion dissociating again outside the hydrogen-oxygen flame to hydrogen and oxygen, whereby the hydrogen and oxygen molecules thus formed partly no longer participate in the combustion process. The product gas produced during combustion then contains hydrogen and oxygen in addition to water vapor. Water vapor of the highest purity can be produced only with a complex post-treatment of the product gas, for example in the form of a catalytic afterburning. Furthermore, with the high adiabatic flame temperature during the combustion of hydrogen and oxygen, high demands are placed on the materials or components used in the combustion chamber. Thus, the outer wall of the combustion chamber in a complex manner to protect against the prevailing in the combustion chamber high temperature. A direct arrangement of ignition devices and measuring sensors in the combustion chamber is not possible due to the high temperature in the combustion chamber in the rule. The introduction of the water into the combustion chamber proves to be problematic in the previously known approach. Thus, the water introduced into the combustion chamber can lead to chain termination reactions in the oxidation process taking place in the combustion chamber due to a concomitant reduction in the flame temperature.

From the US Pat. No. 7,128,624 B1 a propulsion system for an underwater vehicle is known. The system includes a hydrogen supply, an oxygen supply and a combustion chamber.

From the DE 102 43 250 A1 is a method and a steam generator for producing water vapor, in particular ultrapure water vapor, by reacting a stoichiometric mixture of a fuel, in particular hydrogen, and an oxidizer, in particular oxygen, and injecting water into the hot reaction gases, which are produced by a high purity of the Steam is known.

From the EP 0 197 555 A2 is a method for producing steam in a steam generator is known, in which one reacts in a hot gas reaction chamber hydrogen and oxygen to steam, in which one heats water in the wall of the hot gas reaction chamber and in which one injects the heated water into the hot reaction gases.

The object of the invention is to provide a method for producing superheated steam of highest purity by combustion of hydrogen and oxygen, in which the described problems of the previously known methods of this type do not occur. It is another object of the invention to provide an apparatus for performing this method.

This object is achieved by a method for generating water vapor having the features specified in claim 1 and with a device for generating water vapor having the features specified in claim 6. Advantageous developments of the method and the device will become apparent from the dependent claims, the following description and the drawings. Here, according to the invention, the specified in the dependent claims 2 to 5 features each alone, but also in a technically meaningful combination, the method of claim 1 and the features specified in the dependent claims 7 to 12 features alone or combined with each other, the device of claim 6 on embellish.

In the method according to the invention for producing water vapor, hydrogen and oxygen are burned with the addition of water in a combustion chamber. The hydrogen and the oxygen are expediently supplied in a stoichiometric ratio in the combustion process. Preferably, the hydrogen is introduced from the oxygen spatially separated into the combustion chamber.

The basic idea of the invention is to introduce liquid water in a common volume flow with the oxygen into the combustion chamber. Unlike previously customary, the liquid water is therefore not introduced in the post-combustion zone of the hydrogen-oxygen flame, but in the preheating and combustion zone of the combustion chamber together with the oxygen. Due to this introduction of the water into the combustion chamber, the adiabatic flame temperature in the combustion chamber is locally reduced compared to the previously customary combustion process management. Thus, the reaction temperature in the combustion chamber in the inventive method is about 950 to 1050 ° C. Advantageously, takes place at this reaction temperature no dissociation of the water vapor generated during combustion, so that no free hydrogen and oxygen molecules are formed in the inventive method and thus water vapor of highest purity can be generated. The outer wall of the combustion chamber and arranged in the combustion chamber components or component groups are exposed in the inventive method a significantly lower thermal load. This makes it possible, if appropriate, to arrange ignition devices and measuring sensors directly in the combustion chamber. Further advantageously, the reaction temperature is above the temperature at which it comes to chain termination reactions of a hydrogen-oxygen mixture. In this respect, a trouble-free process is guaranteed in this regard.

In an advantageous development of the method according to the invention, it is provided to add additional liquid water to the combustion chamber on the output side of the steam generated in the combustion chamber. With this measure, the possibility is created to adjust the amount of steam and especially the temperature of the water vapor generated. The temperature control is typically carried out via the amount of the water vapor supplied to the liquid water, which also evaporates due to the temperature of the already existing water vapor. As a result of the addition of the additional water, the steam has a lower temperature than the water vapor present before the addition of the additional liquid water. In contrast to the hitherto known processes for the generation of steam by the combustion of hydrogen and oxygen, it is thus possible to realize steam temperatures which lie in a range below 200 ° C.

Although the reaction temperatures prevailing in the combustion chamber in the method according to the invention are comparatively low, it is preferably provided to cool the combustion chamber on its outer side so as to dissipate the heat absorbed by the outer wall of the combustion chamber. In this case, the water to be evaporated is particularly advantageously used beforehand for cooling the outer wall of the combustion chamber. Ie. Preferably, water, which is led along to form a cooling flow on the outside of the combustion chamber, then, after it has absorbed heat from the outer wall of the combustion chamber, passed in a common volume flow with the oxygen in the combustion chamber and / or the output side of the combustion chamber in the Combustion chamber generated water vapor added. Accordingly, the water before it is introduced together with the oxygen in the combustion chamber or the output side of the combustion chamber is added to the water vapor generated in the combustion chamber, advantageously already preheated.

Conveniently, the water is homogeneously mixed with the oxygen introduced into the combustion chamber. Thus, it is preferably provided that the water supplied to the combustion chamber is atomized before being introduced into the combustion chamber by means of the oxygen stream. The resulting oxygen-water mist is then introduced into the combustion chamber. The atomization of the water causes an improvement in the heat exchange between the hydrogen-oxygen flame and the water and, consequently, an acceleration of the evaporation process of this water.

With the aim of improving the heat exchange between the water vapor generated in the combustion chamber and the water added to the output side of the combustion chamber liquid water and to effect a rapid evaporation of the liquid water is provided in a similar manner, preferably also the water vapor generated in the combustion chamber To atomize added liquid water, for which purpose the steam stream is used as propellant gas.

The inventive device for generating water vapor has a combustion chamber with a hydrogen inlet and an oxygen inlet. The hydrogen inlet and the oxygen inlet preferably open at a distance from one another into the combustion chamber. To go in the combustion chamber to be able to introduce liquid water in a common volume flow with the oxygen, the oxygen inlet is connected on the input side via a lockable supply line to a water source. In other words, besides a supply line leading from an oxygen source to the oxygen inlet, another supply line coming from a water source is connected to the oxygen inlet.

To derive the water vapor generated by the combustion of the hydrogen with the oxygen and by evaporation of the liquid water, a steam outlet is arranged on the combustion chamber. Preferably, this steam outlet opens on the output side of the combustion chamber into a mixing chamber, which also has a water inlet for liquid water. Accordingly, downstream of the combustion chamber is arranged a space into which the steam can directly flow from the combustion chamber, where the water vapor is then mixed with further water vapor formed by evaporating liquid water, which is passed via the water inlet into the mixing chamber. Conveniently, a controller may be provided, with which the introduced via the water inlet into the mixing chamber amount of water is controllable, which then also the temperature of the water vapor generated in the device according to the invention can be controlled.

According to a further advantageous embodiment of the invention, the hydrogen inlet is arranged on the combustion chamber concentrically around the oxygen inlet. Here, the hydrogen inlet may be annular or, as is preferably provided, may be formed by a plurality of hydrogen inlet openings arranged annularly at a radial distance from the oxygen inlet therearound. This radial distance of the oxygen inlet from the hydrogen inlet, and preferably also a distance in the outflow direction of the oxygen inlet between the oxygen inlet and the hydrogen inlet advantageously prevent heat transfer from the hydrogen-oxygen flame to the oxygen inlet, so that the oxygen inlet is protected from excessive thermal load.

In principle, an inlet for introducing the water vapor coming from the combustion chamber and a further inlet for introducing the additional liquid water can be formed on the mixing chamber. Preferably, however, it is provided that the steam outlet of the combustion chamber also forms the water inlet of the mixing chamber. Accordingly, the mixing chamber preferably has only one flow inlet, which is formed by the steam outlet of the combustion chamber, wherein in the flow path through this steam outlet, a supply line coming from the water source flows through which liquid water can flow into the steam outlet and from there into the mixing chamber.

Conveniently, the steam outlet is designed such that the water supplied to it is atomized in it. Advantageously, therefore, the steam outlet is a nozzle, wherein it is preferably provided that the steam outlet is designed as a critical nozzle. The use of a critical nozzle as the steam outlet of the combustion chamber has the advantage that it can be used to realize a constant flow of steam into the mixing chamber. Another advantage of using the critical nozzle As the steam outlet of the combustion chamber or as a water vapor inlet of the mixing chamber is to be seen in that the combustion chamber is thereby decoupled from pressure fluctuations, which may occur in the device according to the invention downstream devices or systems.

In order to assist the evaporation process of the liquid side water added to the output side of the combustion chamber and to assist in mixing the water vapor generated in the combustion chamber with the water vapor generated in the mixing chamber and to prevent local temperature differences in the mixing chamber, the mixing chamber is preferably a porous material filled. This porous material may advantageously be a wire mesh, which forms a comparatively large porous and thus gas-permeable surface due to the meshes formed therein.

In order to protect the outer wall of the combustion chamber during the running therein of combustion of hydrogen and oxygen from excessive heat stress, at least one flow-connected with a water source cooling water channel is expediently formed on the outer wall of the combustion chamber. Particularly advantageously, this cooling water channel is connected downstream with the oxygen inlet of the combustion chamber and / or with the water vapor outlet of the combustion chamber. In this respect, the cooling water channel in this embodiment forms part of the supply line from the water source to the oxygen inlet of the combustion chamber and a part of the supply line from the water source to the water vapor outlet of the combustion chamber and the water vapor inlet of the mixing chamber.

As a further advantageous measure for protecting the outer wall of the combustion chamber and for protecting the oxygen inlet and the hydrogen inlet, thermal insulation materials, in particular thermal insulation panels, can be arranged in the combustion chamber. The heat absorbed by these thermal insulation panels can then be removed from the combustion chamber via the at least one cooling water channel arranged on the outer wall of the combustion chamber.

With the method according to the invention for producing steam and with the device according to the invention for this purpose, it is possible to produce superheated steam at low temperature near the saturated steam line. Superheated steam at this temperature range will be used to regenerate the submarine CO2 binders used to bind the CO2 contained in the air inside the submarine. Therefore, the device according to the invention is also particularly suitable for use in a submarine. In this respect, the invention also relates to a submarine, which has a device for generating water vapor with the features described above.

Fig. 1

schematisch sehr stark vereinfacht eine Vorrichtung zur Erzeugung von Wasserdampf,

Fig.2

in einem Längsschnitt eine Ausgestaltung der Vorrichtung nach Fig. 1,

Fig. 3

eine Einzelheit A aus Fig. 1,

Fig. 4

eine Einzelheit B aus Fig. 1 in einem Halbschnitt und

Fig. 5

in einer Prinzipdarstellung den Ablauf eines Verfahrens zur Erzeugung von Wasserdampf.

The invention is explained in more detail with reference to an embodiment shown in the drawing. In the drawing shows:

Fig. 1

schematically very simplified a device for generating water vapor,

Fig.2

in a longitudinal section an embodiment of the device according to Fig. 1 .

Fig. 3

a detail A from Fig. 1 .

Fig. 4

a detail B off Fig. 1 in a half cut and

Fig. 5

in a schematic representation of the sequence of a method for generating water vapor.

In the Fig. 1 as well as in Fig. 2 illustrated apparatus for generating water vapor has a combustion chamber 2, in which gaseous hydrogen H _{2 (g)} and gaseous oxygen O _{2 (g) are} burned, wherein as product gas steam H ₂ O _(g) is formed. The combustion chamber 2 is formed by a substantially cylindrical housing 4, whose open end faces are closed by end plates 6 and 8.

At the end plate 6, an oxygen inlet and a hydrogen inlet are formed ( Fig. 3 ). The oxygen inlet is formed by a nozzle 10 which is centrally located on the end plate 6. The hydrogen inlet into the combustion chamber 2 form twelve hydrogen inlet openings 12, which are formed at a radial distance from the nozzle 10 in an annular manner around it. At the combustion chamber 2 side facing a conical recess 14 is formed on the end plate 6. At the tapered end of this recess 14, the nozzle 10 opens.

In addition to the oxygen O _{2 (g)} , liquid water H ₂ O _{(fl) is also introduced} into the combustion chamber 2 via the nozzle 10 as the oxygen inlet. For this purpose, a connection 16 for connecting a supply line coming from an oxygen source and a connection 18 for connecting a supply line coming from a water source are formed on the inlet side of the nozzle 10. On the representation of the oxygen source, the water source and the supply lines has been omitted for reasons of clarity.

The housing 4 and the end plate 6 are clad on their inner side facing the combustion chamber 2 with thermal insulation panels 20. Through the end plate 6, an igniter 22 of an electric ignition device is guided into the interior of the combustion chamber 2, which serves there for generating a hydrogen-oxygen flame.

At the end plate 8, a water vapor outlet 24 is arranged centrally. This steam outlet 24 is formed by a critical nozzle. At a radial distance around the steam outlet 24, a plurality of relief bores 26 are arranged on the end plate 8. The steam inlet 24 opens into a mixing chamber 28. This mixing chamber 28 is formed by a substantially cylindrical housing 30, which is flanged to the end plate 8 on the side facing away from the combustion chamber 2 side. An outlet 32 is formed on the housing 30 at an end remote from the end plate 8. In the mixing chamber 28 are in the flow path of the hydrogen outlet 24, which forms a hydrogen inlet into the mixing chamber 28, and the outlet 32 in succession a plurality of segments 34 made of a porous material, such. B. wire knit arranged.

On the outside of the combustion chamber 2 forming the housing 4 is a helically around the circumference of the housing 4 spiraling groove 36 is formed. The groove 36 serves to receive a cooling water channel in the form of a line 38. On the inflow side, the line 38 is connected to a water source, not shown in the drawing. Downstream of the conduit 38 there is also a flow connection, not shown in the drawing, between the conduit 38 and the nozzle 10 and between the conduit 38 and the water vapor outlet 24 formed on the end plate 8, a portion of this conduit connection being formed by a bore 40 formed on the end plate 8 ( Fig. 4 ) is formed, which extends from the outside of the end plate 8 radially inwardly and opens into the steam outlet 24.

• Zur Erzeugung von Wasserdampf H₂O_(g) wird der Brennkammer 2 voneinander räumlich getrennt Wasserstoff H_2(g) und Sauerstoff O_2(g) im stöchiometrischen Verhältnis zugeführt. Die Einleitung des Wasserstoffs H_2(g) erfolgt über die Wasserstoffeinlassöffnungen 12, während der Sauerstoff O_2(g) über die Düse 10 in die Brennkammer 2 eingeleitet wird. In der Brennkammer 2 wird das Wasserstoff-Sauerstoff-Gemisch mittels des Zünders 22 gezündet, woraufhin es unter Bildung einer Wasser-Sauerstoff-Flamme verbrennt und als Produktgas reiner Wasserdampf H₂O_(g) erzeugt wird.

The procedure when using the device shown in the drawing is as follows:

• In order to generate steam H ₂ O _(g) , the combustion chamber 2 is supplied with hydrogen H _{2 (g)} and oxygen O _{2 (g)} in a stoichiometric ratio in a spatially separated manner. The introduction of the hydrogen H _{2 (g)} takes place via the hydrogen inlet openings 12, while the oxygen O _{2 (g) is introduced} into the combustion chamber 2 via the nozzle 10. In the combustion chamber 2, the hydrogen-oxygen mixture is ignited by means of the igniter 22, whereupon it burns to form a water-oxygen flame and as product gas pure water vapor H ₂ O _{(g) is} generated.

During the combustion of the hydrogen H _{2 (g)} with the oxygen O _{2 (g)} , the combustion chamber 2 is cooled by means of water flowing through the line 38 H ₂ O _(fl) . Part of this water H ₂ O _(fl) is supplied to the oxygen stream in the nozzle 10, from where it enters the combustion chamber 2 atomized with the oxygen O _{2 (g)} . There, the water evaporates H ₂ O _(fl) to additional water vapor H ₂ O _(g) . By the oxygen O _{2 (g)} introduced into the combustion chamber 2 water H ₂ O _(fl), the reaction temperature in the combustion chamber 2 only 950 to 1050 ° C.

About the Wasserdampfauslass 24 of the water vapor passes H ₂ O _(g) of the combustion chamber 2 into the mixing chamber 28, wherein the water vapor stream in the Wasserdampfauslass 24 is a further part of the current flowing to the cooling of the combustion chamber 2 through line 28 water H ₂ O _(fl) is added and thus enters the mixing chamber 28. Previously, this water is sputtered from the water vapor stream flowing through the water outlet 24 H ₂ O _(fl) . Due to the temperature of the water vapor H ₂ O _(g) and the liquid water H ₂ O _{(fl )} evaporated to steam H ₂ O _(g) , the water vapor H ₂ O _(g) but due to the mixing with the liquid water H ₂ O _(fl) heat is removed. In this way, the temperature of the water vapor H ₂ O _(g) in dependence on the water vapor H ₂ O _(g) supplied amount of liquid water H ₂ O _(fl) in the mixing chamber 28 in a wide range.

The generated water vapor H ₂ O _(g) leaves the mixing chamber 28 through the outlet 32, where it is available for a variety of applications. Previously, it is homogenized in the mixing chamber 28 with respect to its temperature by flowing through the porous segments 34 located in the mixing chamber 28.

LIST OF REFERENCE NUMBERS

2

- combustion chamber

4

- Casing

6

- End plate

8th

- End plate

10

- Jet

12

- Hydrogen inlet opening

14

- Deepening

16

- Connection

18

- Connection

20

- thermal insulation board

22

- detonator

24

- Steam outlet

26

- Relief bore

28

- mixing chamber

30

- Casing

32

- outlet

34

- Segment

36

- groove

38

- Management

40

- Drilling

H _{2 (g)}

- hydrogen

H ₂ O _(fl)

- Water

H ₂ O _(g)

- Steam

O _{2 (g)}

- oxygen

Claims (13)

1. Method for generating water vapor (H₂O_(g)), in which hydrogen (H_2(g)) and oxygen (O_2(g)) are combusted in a combustion chamber (2) while adding water (H₂O_(fl)), characterized in that the water (H₂O_(fl)) in a liquid state is directed into the combustion chamber (2) in a common volume flow with the oxygen (O_2(g)).
2. Method according to Claim 1, characterized in that additional liquid water (H₂O_(fl)) is added on the outlet side of the combustion chamber (2) to the water vapor (H₂O_(g)) which is generated in the combustion chamber (2).
3. Method according to one of the preceding claims, characterized in that liquid water (H2O(fl)) which is to be evaporated is used in advance for cooling the outer wall of the combustion chamber (2).
4. Method according to one of the preceding claims, characterized in that the water (H2O(fl)) which is fed to the combustion chamber (2) is atomized by means of the oxygen stream before introduction into the combustion chamber (2).
5. Method according to Claims 2 and 4, characterized in that the water (H2O(fl)) which is added on the outlet side of the combustion chamber (2) to the water vapor (H2O(g)) which is generated in the combustion chamber (2) is atomized by means of the water vapor stream.
6. Apparatus for generating water vapor (H2O(g)), featuring a combustion chamber (2) which has a hydrogen inlet and an oxygen inlet (10), characterized in that the oxygen inlet (10) is connected on the inlet side to a water source via a feed pipe which can be shut off.
7. Apparatus according to Claim 6, characterized in that on the outlet side of the combustion chamber (2) a water vapor outlet (24) opens into a mixing chamber (28) which has a water inlet.
8. Apparatus according to one of Claims 6 or 7, characterized in that the hydrogen inlet is arranged on the combustion chamber (2) concentrically around the oxygen inlet (10).
9. Apparatus according to Claim 7 or according to Claims 7 and 8, characterized in that the water vapor outlet (24) of the combustion chamber (2) forms the water inlet of the mixing chamber (28).
10. Apparatus according to Claim 7 or according to Claims 7 and 8 or according to Claims 7, 8 and 9, characterized in that the water vapor outlet (24) is designed as a critical nozzle.
11. Apparatus according to one of Claims 7 to 10, characterized in that the mixing chamber (28) is filled with a porous material.
12. Apparatus according to one of Claims 6 to 11, characterized in that at least one cooling water passage, which is fluidically connected to a water source, is formed on an outer wall of the combustion chamber (2), and on the outflow side is fluidically connected to the oxygen inlet (10) in the combustion chamber (2) and/or to the water vapor outlet (24) of the combustion chamber (2).
13. Submarine, characterized in that it has an apparatus for generating water vapor (H2O(g)) having the features which are disclosed in Claims 6 to 12.

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