DE10212081A1 - Device for feeding educts into a reaction space - Google Patents

Abstract

A device is used for supplying educts into a reaction space, wherein at least one of the educts is a hot gas stream and at least one other of the educts is a liquid to be evaporated therein. The device has at least one device for introducing the liquid into the hot gas stream. DOLLAR A According to the invention, the device further has the following features: DOLLAR A - a subsequent to the at least one means for introducing the liquid into the hot gas stream, perfused by the mixture of educts line length for generating a turbulent flow; DOLLAR A - an adjoining line length to align the flow. DOLLAR A The preferred use of such a device can be seen for example in the metering and evaporation of liquid hydrocarbon-containing compounds for an autothermal reformer, which hydrogen-rich gas z. B. for a fuel cell APU.

Description

The invention relates to a device for supplying educts in a reaction space, wherein at least one of the educts hot gas stream and at least one other of the educts one liquid to be evaporated therein is at least one Device for introducing the liquid into the hot gas stream.

From US 6,126,908 is a device for converting a hydrocarbonaceous fuel or an alcohol in hydrogen-rich gas and carbon dioxide known. This is air or another oxygen-containing gas over one Heat exchanger along a reaction zone in which an exothermic Reaction takes place, directed. Just before reaching a Before the reaction zone arranged mixing zone, the addition takes place fuel or alcohol in the thus produced hot Airflow. The mixture of liquid fuel and hot air then passes into the comparatively large, empty mixing zone, before it flows into the region of the reaction zone, in which a catalytically active material is arranged.

The structure described by the above-mentioned U.S. Patent has the disadvantage that the mixing of the hot Air flow with the liquid fuel uncontrolled and not reproducible in the mixing zone, whereby the flow of the catalyst is inhomogeneous with the mixture. In addition to this inhomogeneous flow of the catalyst can optionally still droplets of the liquid propellant in the Mixture containing the reaction of the mixture to the Catalyst hinder and / or this catalyst by a Inhibit occupancy with fluid in its activity. Nevertheless a satisfactory mode of operation of the catalytic conversion To achieve the mixing zone must be comparatively large become. Likewise, the reaction zone with the catalytic active material be chosen sufficiently large, so that the Mixture when leaving the reaction zone sufficiently implemented. Due to the large reaction zone results next the disadvantage of the high demand for space also the Disadvantage that requires comparatively high amounts of catalyst become. Since the material used for the catalyst in General precious metals are by the above described structure thus incurred correspondingly high costs.

An alternative to this is by DE 199 29 945 C1 described. The indicated reactant delivery system for delivery of feedstocks for chemical conversion into one Reaction space includes nozzle means for supplying the starting materials in the Reaction chamber. These nozzle means are considered to be one at the entrance into formed the reaction chamber arranged mixing nozzle, which Inlet channels for at least two of the starting materials. The separately supplied via the inlet channels feedstocks are mixed in the mixing nozzle and then appear as "finished" mixture in the reaction space. The concrete one Design of these mixing nozzles sees one in the manner of a Venturi nozzle trained cross-sectional constriction in a gas stream before, wherein in the area of this cross-sectional constriction the above already mentioned inlet channels open, so that with the help of forming negative pressure an atomization of liquid Feedstocks in a gaseous feedstock, which are caused by the Venturi nozzle flows, can take place.

Through this structure, the mixing of the Starting materials and the atomization of liquid introduced feedstocks optimize, so that the supply of starting materials for the reaction space is improved. Depending on the pressure conditions In the area of the mixing nozzle, a fine atomization can take place be realized, so that both the distribution of the liquid as well as the evaporation of the liquid can be improved.

With such a structure you buy the good Functioning, however, by the disadvantage of a relatively high Energy input, because for a good atomization comparatively high Pressures are needed.

Based on these problems, it is the task of here present invention, an apparatus for supplying educts in to provide a reaction space, wherein at least one of Edukte a hot gas stream and at least another of the Educts is a liquid to be evaporated therein, wherein the A very good device with minimal use of energy Evaporation and distribution of the liquid in the hot gas stream and the device is intended for the Functioning of the reaction chamber optimized inflow of the To allow reactants in the same.

According to the invention this object is achieved by a device solved, which is a to the at least one device for Introducing the liquid into the hot gas stream subsequent, flowed through by the mixture of educts line length to Generating a turbulent flow and a to it has subsequent line length for aligning the flow.

By the inventive line length for generating a turbulent flow after the device for introduction of the Liquid in the hot gas stream is on the one hand a very good mixture of incorporated educts, on the other hand is a very efficient due to the turbulent flow Heat transfer from the hot gas stream to the liquid, so that it evaporates in an ideal way and optionally can also be overheated. It is characterized by the line length even a sufficient residence time of the mixture in the range the turbulent flow allows.

At this area with the turbulent flow closes then according to the invention, a further line length, which serves to align the flow. With this cable length the flow is homogenized and through the given shape the line targeted, so that the mixture of Educts can ideally flow into the region of the reaction space. As very advantageous side effect results from the Possibility, the reaction space comparatively small, what here synonymous with a short to be flown through the length of Reaction space is to perform, because by the orientation of the Flow an optimal flow and thus the fastest possible Sales of starting materials within a very short residence time is guaranteed. Besides the obvious advantages with regard to saving space and catalyst material There is also an energetic advantage because the Throughflow of catalysts always generates pressure losses, which with a shortening of the length of the catalyst to be flowed through also sink.

According to a very favorable development of the device for Feed of the starting materials into the reaction space is the length of the line to generate the turbulent flow thereby formed that they have frequent changes in the direction of flow in it forces flowing educts.

This particularly favorable embodiment can in advantageously achieves a comparatively high turbulence be without a large flow pressure loss in the educts is produced.

According to a very favorable development of this embodiment the invention is the line length for generating the turbulent flow formed as a coiled tubing.

This use of a coiled tubing allows a continuous occurring change in the direction of flow in her flowing educts, creating a sufficiently turbulent flow to achieve the effects already described above and Benefits generated. The coiled tubing also has a Relatively small pressure loss can be and even at relative long cable length in a comparatively small space accommodate, so that the device according to the invention, when They according to the training described here with the Pipe helix is executed, in terms of pressure losses and can be optimized in terms of space.

To the best possible flow of the reaction space with the To ensure educts is according to a very advantageous Embodiment of the invention, the main axis of the cable length to Aligning the flow at least approximately parallel to the Direction of the main flow through the reaction space educated.

This allows a uniform flow of the reaction space be achieved so that this one hand, used very effectively and on the other hand be minimized in terms of its space can. The result of such an optimization of the installation space the reaction space basically resulting advantages already mentioned above. By the measures shown here for Development of the invention will these advantages, which on the one hand in the minimized space of the entire device and on the other hand to see in the minimized space of the reaction space are used even more intensively. The use of catalytic active material as well as the installation space and the pressure losses be further reduced.

The line length for aligning the flow is according to a very favorable development of the invention as at least formed approximately straight pipe section.

This allows the flow coming from the coiled tubing be aligned, so that the subsequent reaction chamber very well and can be flowed evenly.

According to a particularly advantageous embodiment of the above said invention is the at least one means for Introducing the liquid in the hot gas stream as in the Gas flow protruding capillary formed.

The up to the gas flow projecting capillary allows with minimal Expenditure of components and in particular for the dosage required energy, a dosage of liquid in the hot gas stream. The due to the lack of high Pressure difference between the liquid and the gas flow is not so optimal to be realized atomization plays due to the two of Device for introducing the liquid into the gas stream downstream line lengths according to the invention a comparatively minor role, so that the capillary as Device for introducing the liquid into the hot Gas flow to minimize the operation of the device vitally required energy.

According to a very favorable embodiment of the above Invention is the reaction space as autothermal Reforming reactor - hereinafter referred to as reformer - for Provision of a hydrogen-containing gas formed.

Especially for such a reformer, the dosage of in a hot gas stream to be evaporated liquid a very big role, as here only very well vaporized and mixed educts the ideal functioning of the reformer can be realized. Because here are the smallest fluctuations, which are can result from the dosage, already serious Effects on the quality and ingredients of the product have hydrogenated reformate, for example, the content of Carbon monoxide, the operation of such a reformer can the device according to the invention for the supply of educts be decisively improved.

Furthermore, the invention shown here according to a very advantageous embodiment, the use of Device according to the invention in a system for generating a hydrogen-containing gas for at least one fuel cell, preferred for the fuel cell of an auxiliary power generator (Auxiliary Power Unit / APU), above.

Especially in such gas generating systems plays the reliable, reproducible and safe operation of the Components which in the case of the reformer by the Device according to the invention for metering the educts can be achieved an important role. For reliable working System components, such as the device according to the invention, Here, a safe operation can be achieved without a lot of effort in terms of monitoring, control and Control of the system must be operated. Furthermore develop from the device according to the invention for the preferred use according to the invention, namely the APU, Further advantages, which are mainly due to the means of According to the invention device to be saved space, since such applications are common in mobile systems, such as For example, vehicles, ships, aircraft or the like, are used, in which savings in weight and Space with corresponding advantages in the areas of comfort, Efficiency optimization and the like correspond.

Further advantageous embodiments of the invention will become apparent from the remaining subclaims and from the basis of the Drawing embodiment shown below.

It shows:

Fig. 1 shows a device according to the invention for feeding reactants into a reaction chamber;

FIG. 2 shows a first embodiment of a device for introducing a liquid into a gas stream; FIG.

3 shows a second embodiment of the means for introducing the liquid into the gas stream.

Figure 4 is a line length for aligning the flow with baffles as a flow straightener. and

Fig. 5 shows a line length for aligning the flow with the internals as a flow straightener in an alternative embodiment.

The exemplary embodiment described below shows an apparatus 1 according to the invention for supplying educts into a reaction space 2 using the example of the supply of hot air and liquid hydrocarbon-containing compounds in an autothermal reformer for generating a hydrogen-rich gas, which is then after passing through suitable gas purification devices for operating a fuel cell should be used. However, the device 1 according to the invention should not be limited to the application shown in the embodiment.

In Fig. 1, the device 1 for supplying reactants A, B is shown in the reaction chamber 2 in a longitudinal section. The device 1 consists, in addition to the not visible in Fig. 1 means 3 for introducing a liquid (here the reactant B) in a hot gas stream (here the starting material A), from a flowed through by the mixture of educts A, B line length 4 for Generating a turbulent flow and an adjoining line length 5 for aligning the flow. The device 1 is arranged together with the reaction space 2 , an autothermal reforming space, in a common housing 6 . This makes it possible to achieve an integrated construction of the device 1 together with the reaction space 2 , which is very compact and thus optimized on the one hand to save space and on the other hand with regard to thermal losses.

The line length 4 for generating the turbulent flow is designed such that it forces frequent changes in the flow direction of the educts flowing in it, in this case the hot gas stream A and the liquid B therein. As a result of this constant change in the flow direction, a turbulent flow in the mixture of educts A, B is achieved. Of course, there are several ways to force such a change in the flow directions. The illustrated in the present embodiment, line length 4 for generating the turbulent flow reaches this change in the flow direction through the configuration of coiled tubing. This coiled tubing 4 allows the achievement of a turbulent flow with minimal pressure losses in the educts A, B flowing in it.

Furthermore, it allows the coiled tubing 4 to accommodate a long line length in a comparatively small space in the device 1 or the housing 6 . Through this long line length of the coiled tubing 4 can be achieved that the means 3 for introducing the liquid B in the hot gas stream A can be relatively easily formed. Due to the length of the coiled tubing 4 and the good mixing between the hot gas stream A and the liquid B due to the turbulent flow and a heat transfer between the hot gas stream A and the liquid B optimized by this turbulent flow, ideal evaporation of the liquid B in FIG the hot gas stream A can be ensured. Therefore, no complex and energy-intensive devices 3 for introducing the liquid B in the gas stream A are necessary, which would atomize the liquid B very finely, for example, at high pressure. Due to the design of the device 1 with the line length 4 for generating a turbulent flow, so here the coiled tubing 4 , the means 3 for introducing the liquid B in the hot gas stream A can be designed simple and energy-optimized.

A preferred embodiment of the means 3 for introducing the liquid B would be, for example, a capillary 3 , which is indicated in principle in Fig. 2. This capillary 3 is due to the very small inner diameter able to promote the liquid B by capillary forces in the region of the hot gas stream A. Such a capillary 3 as means for introducing the liquid B in the hot gas stream A requires no auxiliary power for dosing. The device 1 with this very simple and energy-saving device 3 for introducing the liquid B in the hot gas stream A, in the present embodiment, a liquid hydrocarbon-containing compound, for. As gasoline or diesel, in a hot air stream, which may optionally contain recirculated from the system vapors and / or added steam, so it allows to dispense with a complex, energy-intensive injection of the liquid B. A sufficiently good mixture of hot gas stream A and liquid B evaporated therein can be provided after flowing through the coiled tubing 4 with a very simple structure and minimum energy expenditure.

In Fig. 2, the capillary 3 is provided with a not necessarily necessary but advantageous elbow 7 , so that the supply of the liquid to be evaporated B through the capillary 3 takes place counter to the flow direction of the hot gas stream A. The distribution of the exiting from the capillary 3 liquid B in the hot gas stream A is favored by the kinetic energy contained in the hot gas stream A, so that a small droplet size of the liquid B is formed in the hot gas stream A. The evaporation of the liquid B in the hot gas stream A is optimized because the ideal evaporation except from the residence time in the evaporation space, here the coiled tubing 4 , and the temperature level of the hot gas stream A also on the droplet size of the liquid B in the gas stream A dependent is.

FIG. 3 shows a further embodiment of the device 3 for introducing the liquid into the hot gas flow A, the flow cross-section of the hot gas flow A being reduced in the region of the capillary 3 in addition to the structure already described in FIG . This reduction of the cross section in the manner of a Venturi nozzle ensures a higher flow velocity of the hot gas stream A in the region of the capillary 3 and thus for a negative pressure in this area. This negative pressure causes a slight suction of the liquid B from the capillary. 3 The atomization of the liquid B can be improved, similar to the processes in a known from the prior art with compressed air operated spray gun for painting or the like. The above effects are further optimized for ideal evaporation. However, the reduction in the flow cross-section ensures increased pressure losses in the gas stream A.

As indicated in Fig. 1, the reaction space 2 in a conventional manner, a carrier material 8 , on which a catalytically active material is arranged. In order to achieve the most uniform possible flow of this support material 8 with the catalytically active material - hereinafter referred to as catalyst support 8 - passes the coiled tubing 4 leaving volume flow of educts A, B via the dashed lines in Fig. 1 indicated compound 9 before flowing in the reaction space 2 first in the line length 5 for aligning the flow. This line length 5 for aligning the flow is formed in the embodiment shown here as at least approximately straight pipe section. This training as a straight pipe section 5 will certainly be the main application of the line length 5 for aligning the flow. However, if a corresponding catalyst support 8 has a different structure and expects a flow which ideally does not result from a flow from a straight pipe section 5 , the line length 5 for aligning the flow may well have other shapes and be adapted to the corresponding catalyst support 8 ,

In the embodiment shown here, the catalyst support 8 is formed so that the structure of the line length 5 for aligning the flow as at least approximately straight pipe section 5 ideally meets the requirements. The straight pipe section 5 is formed with its main axis, ie the central axis of the pipe section 5 , at least approximately parallel to the direction of the main flow through the reaction space 2 . The optimum flow of educts A, B into the region of the reaction space 2 can thus be ensured. In catalyst carriers 8 , which are realized with a different geometry, but it also makes sense if the main axis of the line length 5 for aligning the flow has a same or similar course, as the main flow direction in the catalyst carrier 8 .

In order to further optimize the alignment of the flow of educts A, B, the pipe section 5 can also have internals 10 as a flow straightener. These fittings 10, as they are in principle as indicated in Fig. 4 and Fig. 5 in two different embodiments, can change the alignment and optimization of the homogeneity of the flow of the educts A, in the pipe piece 5 further improve B. These optional fittings 10 in the pipe section 5 may be of particular interest if the length of the pipe section 5 is comparatively small and at the shortest length of the pipe section 5 as good as possible alignment and homogenization of the flow to be achieved. However, the internals 10 provide for slightly increased pressure losses in the volume flow of the starting materials A, B.

In most cases, the present in such a device 1 line lengths 4 , 5 , in particular the ratio of the line length 4 for generating the turbulent flow, so here the coiled tubing 4 , to the length of the line length 5 for aligning the flow, in this case the straight Pipe piece 5 , approximately formed so that the coiled tubing 4 has 5 to 15 times the length of the straight pipe section 5 . This makes it possible for the underlying embodiment of the autothermal reforming an ideal combination of complete evaporation of the liquid B in the hot gas stream A and an alignment of the flow of the reactants A, B reach. When using different starting materials A, B and another desired reaction in the reaction space 2 , however, the length ratios can be modified according to the starting materials A, B used and the desired reaction.

In order to additionally improve the flow of the catalyst support 8 , the area between the straight pipe section 5 and the catalyst support 8 may further comprise means 11 for uniformly comparing the flow to the cross-sectional area of the catalyst support 8 . In the embodiment shown in FIG. 1, these devices 11 are designed as a diffuser, which is formed here by a cone which widens toward the catalyst carrier 8 . In addition, the diffuser 11 could additionally have corresponding internals for distributing and homogenizing the flow of the catalyst carrier 8 . However, this area plays a subordinate role for the invention presented here, so that it will not be discussed further here. Without taking any influence on the scope of the invention, however, this structure could also be designed fundamentally differently.

The structure of the device 1 shown in the present embodiment serves, as already mentioned, to provide a mixture of hot air and hydrocarbon-containing compounds vaporized therein for the autothermal reforming in the reaction space 2 . The resulting hydrogen-rich gas is to be supplied after passing through other from the prior art known per se purification devices of a fuel cell and there together with atmospheric oxygen to provide electrical energy. Due to the structure shown here, an energy-optimized provision of the educts A, B can be realized, which is also able to manage with a comparatively small space. Accordingly, the preferred application for such a device 1 in the range of a fuel cell-powered auxiliary power unit (APU) to see which z. B. can be used in motor vehicles to produce from the fuel tanks in any case entrained hydrocarbonaceous fuel, such as gasoline or diesel, a hydrogen-rich gas and to use this to provide electrical energy with the best possible efficiency in a fuel cell APU.

Claims (17)

1. A device for supplying educts in a reaction space, wherein at least one of the educts is a hot gas stream and at least one of the educts is a liquid to be evaporated therein, with at least one means for introducing the liquid into the hot gas stream, characterized by the following features : 1. 1.1 a to the at least one means ( 3 ) for introducing the liquid (B) in the hot gas stream (A) subsequent of the mixture of educts (A, B) flowed through line length ( 4 ) for generating a turbulent flow; and 2. 1.2 an adjoining line length ( 5 ) for aligning the flow. 2. Apparatus according to claim 1, characterized in that the line length ( 4 ) for generating the turbulent flow is formed so that it forces at least some changes in the flow direction of the educts flowing in it (A, B). 3. Apparatus according to claim 2, characterized in that the line length ( 4 ) is designed to generate the turbulent flow as a tube spiral. 4. Apparatus according to claim 1, 2 or 3, characterized in that the at least one means ( 3 ) for introducing the liquid (B) in the hot gas stream (A) is formed as in the gas stream (A) projecting capillary. 5. The device according to claim 4, characterized in that the capillary ( 3 ) is formed so that the supply of the liquid to be evaporated (B) through the capillary ( 3 ) counter to the flow direction of the hot gas stream (A). 6. Apparatus according to claim 4 or 5, characterized in that the flow cross-section of the hot gas stream (A) is reduced in the region of the capillary ( 3 ) at least opposite the arranged in the flow direction before areas. 7. Device according to one of claims 1 to 6, characterized in that the line length ( 5 ) for aligning the flow with its main axis is at least approximately parallel to the direction of the main flow through the reaction space ( 2 ). 8. Device according to one of claims 1 to 7, characterized in that the line length ( 5 ) for aligning the flow is formed as at least approximately straight pipe section. 9. Device according to one of claims 1 to 8, characterized in that the line length ( 5 ) for aligning the flow internals ( 10 ) has as a flow straightener. 10. Device according to one of claims 1 to 9, characterized in that the line length ( 4 ) for generating the turbulent flow has 5 to 15 times the length of the line length ( 5 ) for aligning the flow. 11. Device according to one of claims 1 to 10, characterized, the hot gas stream (A) has at least hot air. 12. Device according to one of claims 1 to 11, characterized, that the liquid (B) at least one hydrocarbon-containing compound, preferably gasoline or diesel. 13. Device according to one of claims 1 to 12, characterized in that the reaction space ( 2 ) has a on a carrier material ( 8 ) arranged catalytically active material. 14. The device according to claim 13, characterized in that arranged between the line length ( 5 ) for aligning the flow and the carrier material ( 8 ) for the catalytically active material means ( 11 ) for uniform distribution of the flow to the cross-sectional area of the carrier material ( 8 ) are. 15. Device according to one of claims 1 to 14, characterized in that the reaction space ( 2 ) is designed as an autothermal reforming reactor for providing a hydrogen-containing gas. 16. Device according to one of claims 1 to 15, characterized in that arranged at least the line length ( 4 ) for generating a turbulent flow, the line length ( 5 ) for aligning the flow and the reaction space ( 2 ) in a common housing ( 6 ) are. 17. Use of the device according to one of claims 1 to 16 in a system for generating a hydrogen-containing Gas for at least one fuel cell, preferably for the fuel cell of an auxiliary power generator (Auxiliary Power Unit / APU).