FR2847489A1 - Integrated reactor with two separated channel structures carrying two fluids, one taking part in a reaction generating heat and with heat transfer between the two at the same time, notably for fuel systems - Google Patents

Abstract

Integrated reactor (10) has two separated channel structures for guiding two streams of fluid. In at least one stream within a reaction area (16), a reaction produces a variation in temperature and at the same time heat transfer between the streams. At least one of the two streams is received in a dosed manner, and the other fluid is distributed throughout the reaction area. An integrated reactor (10) has two separated channel structures for guiding two streams of fluid. In at least one stream within a reaction area (16), a reaction produces a variation in temperature and at the same time heat transfer between the streams. At least one of the two streams is received in a dosed manner, and the other fluid is distributed throughout the reaction area. The dosing operation is carried out by a structure comprising a metal or plastic perforated film, or by a porous ceramic structure. Independent claims are also included for: (1) a method for conducting in a precise manner a reaction in the integrated reactor; (2) application of the integrated reactor for the efficient evaporation and superheating in fuel cell systems; and (3) application of the integrated reactor for selective oxidation of carbon monoxide in fuel cell systems.

Description

Field of the Invention The present invention relates to an integrated reactor

  having at least two spatially separated channel structures for guiding at least two fluid streams, with in at least one fluid stream within a reaction range a reaction which produces a change in temperature and in same time a heat transfer between the veins

of fluid.

  The invention also relates to a method for precisely conducting a reaction in an integrated reactor having at least 1o two channel structures separated from each other in space to conduct at least two fluid veins, in at least a flow of fluid within a reaction range, a temperature-changing reaction

  and at the same time heat transfer between the fluid valves.

  STATE OF THE ART In many technical applications, there are process steps consisting in exchanging heat between two fluids. This heat exchange or flow can be used to cool the hottest fluid and heat the coldest fluid (basic operation of heat exchange). If in one of the fluids there are reactions, the problem can consist in influencing the reaction temperature and the evolution of the temperature in the reactor by the integration of heat exchange functions in the same device. Thus, for example, document US-A-5,283,050 describes an integrated reactor which is able to mix or react two or more fluids. The reactor consists of a

  porous element with a housing having at least two inputs and one output.

  In large industrial plants such processes are used in different processes, for example for the intermediate cooling of reactors with exothermic reaction. The heat exchange function in conventional tubular (solid bed) reactors is however generally separated in the space of the reactors themselves: the exothermic heat exchangers or in the heat exchange zones integrated in the reactors, intermediate cooling is used and the endothermic reactions at high temperature are carried out in tubular reactors integrated into the combustion chambers. The heat exchange which is not optimum, for example in the case of combustion by an external flame, leads to a large volume requirement for process steps and large energy flows than the exhaust gases d 'a combustion chamber described must evacuate. In the case of a catalytic endothermic conversion of hydrocarbon with steam to give a synthesis gas, for example in conventional reforming reactors, only about half of the energy supplied from the fuel gas stream is used to increase the enthalpy of the reaction. The other half escapes from the

  combustion chamber in the form of a hot exhaust gas.

  In large industrial plants, this energy in the form

  loss heat flux can frequently still recover.

  In recent years it has become more and more

  interesting to improve the energy efficiency of refining processes.

  This interest has resulted in the development of various processes in which the injection of energy for the execution of an endothermic reaction

  could be improved by reformers with heat exchanger.

  This construction is frequently analogous to that of heat exchangers.

tube bundle heat.

  In addition to improving the energy efficiency of continuous processes at very high throughput, we have also encountered areas of application characterized by relatively small quantities of products and very strict conditions of compactness and energy efficiency. As an example there is the conversion of natural gas reserves not yet used to obtain high value products in compact and transportable local installations. An economic motivation supports this application, because with 95% of the gases produced, one cannot transport enough gas as if the transport of a liquefied gas25 were financially attractive. In addition, compact devices are known which can be used for decentralized or mobile applications. Potential applications are, for example, those of reaction steps in decentralized energy supply systems using fuel cells in the mobile field with compact devices for

  auxiliary power generation in motor vehicles.

  The efficient coupling of the heat exchange functions in general devices is carried out in large industrial installations for numerous applications of the state of the art, for example by plate heat exchangers. The achievements known so far can however meet the requirements of a

  mass production for many industrial processes, achievable on a small scale or only possible in a modified form.

  The energy efficient integration of heat exchange and reaction functions is a field of research in progress and is not yet feasible for applications in the field <500 kW, independently of the question of the cost for many reaction systems. This is particularly true if the reactions take place in a catalytic, heterogeneous manner, and are highly dependent on temperature. A current area of research is, for example, that of the energy efficient coupling of several continuous reactions, executed separately in space in a device. With the aid of the forms of apparatus known hitherto, for various reaction systems which are advantageous from an industrial point of view, no convincing embodiment is known which allows thermal integration.

  efficient and functioning in one device.

  The difficulty of coupling the reactions in a device for a separate pipe in the space of stream of heat-generating and receiving heat fluid, as in a tubular reactor, stems from the fact that the temperature dependence of the reactions conducted separately in space, also depends on the kinetics of each reaction system as well as the operating point of the reactor (the

  concentrations of educts as well as flows of educts). As the state variables strongly depend on the location, the temperature control in integrated reactors is a very important problem.

  It is advantageous to conduct fluids in principle as in a tubular flow reactor, the distribution / fluid collection ranges being able to be integrated directly into the device. In particular, reaction systems are envisaged in which, with the aid of one or more lateral supply systems, in at least one of the reaction fluids, the conversion rate is precisely influenced and thus the temperature evolution in integrated reactors. This is true for example for reaction systems in which the reaction rate in conventional tubular reactors or monolithic structures is still considered too high in the input range, so that the temperature dependence produced by the reaction cannot distribute regularly in the reactor. An example is that of oxidation reactions, in particular reactions

  total oxidation or selective oxidation.

  The realization of a side feed in compact reactors is a known solution. Thus the document WO 01/54806 describes a reactor with a reaction zone and heat exchange means of the plate type; the heat exchange means cooperate with the reaction zone and the heat exchanger means consists of a set of superimposed plates in which channels for fluids are formed, according to a predefined pattern. The fluid channels are aligned to form discrete heat exchange paths for the fluids. The process described in this document as well as other proposals are characterized, however, by an absence of flexibility since a lateral supply is only possible at defined locations in the 1o reactor by special supply channels and distribution structures. for each side feed. In addition, it is not possible to have mass production, economical, because in this concept it is necessary to achieve a surface bond between the metal layers by diffusion welding processes. A dosing / supply of fluid, of different amplitudes carried out locally in a distributed manner in two dimensions of space and for each layer of material cannot be

  realized using the concept presented above.

  Multifunctional devices integrating several basic process operations such as heat exchange and at least one reaction, do not currently allow to realize a convincing concept for a locally distributed fluid supply, very flexible, in

  combination with the possibility of mass production.

  SUMMARY OF THE INVENTION The purpose of the present invention is to remedy these drawbacks and to this end relates to an integrated reactor of the type defined above, characterized in that at least one of the two streams of fluid receives in metered manner, at least one other fluid spreads throughout the

reaction range.

  The invention also relates to a method of the type described above, characterized in that at least one of the two fluid streams receives in a distributed manner throughout the reaction range at least one

  other fluid added in a metered manner.

  The invention thus allows temperature or reaction control in the reactor which can be better influenced to arrive

  efficient coupling of the heat exchange fluid streams.

  According to another advantageous characteristic of the reactor

  according to the invention, it is formed of several layers of material in parallel.

  If the fluid added in a metered manner is supplied by transverse channels perpendicular to the direction of flow of the veins of fluid, preferably the transverse channels are integrated in the layer of material which conducts the vein of fluid and in which one does not dose another fluid. If the metered addition of at least one other fluid into the corresponding channel structure is carried out by a metering structure, the metering structure is flat and arranged parallel to the layers of material and / or the metering structure is a film provided of perforations, for example made of metal or plastic, the size and number of perforations

  is variable depending on their local position on the film.

  In addition, the metering structure is a porous ceramic structure. Preferably the pressure drop in the transverse channels is less than that in the metering structure.

  If the fluid added by metering is variable along the reaction range, the supply of fluid added by metering is divided between

  multiple areas along the reaction range.

  In general at least one channel structure has a catalytic coating and the channel structures, separated from each other

  others have different geometries.

  Advantageously for the method, the fluid added in a metered manner is supplied by transverse channels perpendicular to the direction of flow of the veins of fluid, and at least this vein of fluid receives the metered fluid via a structure dosing

flat with perforations.

  The invention makes it possible to provide applications for the integrated reactor, for example for energy-efficient evaporation and for the overheating of mobile and stationary fuel cell systems, for the selective oxidation of carbon monoxide in

fuel cell systems.

  Drawings The present invention will be described below in more detail with the aid of exemplary embodiments represented schematically in the appended drawings in which: FIG. 1 is a top view of an integrated reactor according to the invention, - Figure 2 shows the planar structure of the geometry of the reactor according to the invention, - Figure 3 is a section through two reactor layers according to the invention, Figure 4 shows an embodiment of a locally different perforation according to the invention, - Figure 5 shows the structure of a particular embodiment of the

reactor according to the invention.

  Description of embodiments

  In an integrated reactor which simultaneously performs heat exchange and reaction functions between two fluids, it is desirable to be able to precisely conduct the reaction in different applications, to be able to influence the temperature development in the reactor better than according to known methods. The expression "influence" means, within the framework of the reactor geometry described below, the metering of a fluid in at least one other fluid. The expression "influence in a precise manner" designates means making it possible to influence the temperature of at least one vein of fluid by the precise dosage of at least one other vein of fluid. The fluids used in the reactor according to

  the invention can be liquid or gaseous or mixtures.

  The invention must allow efficient coupling of heat exchange fluids in a device. The expression "efficient coupling" means a high efficiency of heat exchange between the fluid streams separated in space as well as the precise action on the temperature field in the reactor by a flexible metering of fluid in at least another vein of fluid. The reactor design must in principle be suitable for mass production. This means that it must be possible to carry out large series of very high quality.

  with reduced use of working time and material.

  The use must be made in particular in devices traversed continuously, having different layers of material leading at least two veins of fluid separated from each other in space and if necessary as part of a setting parallel to the fluid lines (see below) with distribution between the channel structures. The expression "in channel structures" hereinafter means in a simplified manner all of the structures conducting the fluids and transferring heat into a layer of material. The practical realization of the geometry of a channel in a channel structure may depend on the location. The section of

  channel is not limited to square or rectangular geometries.

  The term "in channel structures" also includes all sections

  possible which may be interesting for reasons of manufacturing or process control.

  The flow guidance is placed in parallel by distributing at least one of the two fluids passing through the device over a group of channels. In the areas of distribution and recombination of the fluids, there will be each time a fluid distributed on a structure of channels of a group of channels. The channel structures of the channel groups can be distributed in different layers of material which result from the symmetrical stacking of different layers of material in a determined order. A group of channels thus consists of all of all

  the channel structures crossed by the same fluid.

  Depending on the process performed, the different channels of a group of channels either have the same geometry or are distinguished according to their location in a plane layer. The different geometries 15 in a layer of material can be justified by considerations of optimization of the distribution of heat, of the exchange of material

  or of the section of the fluid in a plane layer.

  At least in one of the channel groups into which another fluid is metered in, there will be at least one reaction. Next to this group of channels there is at least one other group of channels which can provide heat exchange and / or reaction functions. The wall structure of the other group of channels can be catalytically coated depending on the reaction functions. Alternatively, the channel groups may also be uncoated and provide only heat exchange functions. In addition, a group of channels can also contain a catalytic material which must be applied directly to the wall structure. The catalytically active material can much more be introduced into the group of channels, for example in the form of a film with catalytic coating and which is bent in three dimensions or also in the form of a pellet of catalyst or

  in another form with a base body provided with a catalytically active coating and then placed in the channel structure of the reactor. Note that each group of channels can be coated separately.

  The catalytic coating can be chosen for each group of channels according to the reaction to be catalyzed. In addition, the coating in the direction of fluid flow may vary locally. Depending on the length of the course, we can in principle have a variation in the quality of the coating. The term "coating quality" means that the composition of the material of the applied layer may vary. This means for example that one can intentionally vary the activity

  catalytic along the axis of the channel; the same channel area can remain free without a catalytic layer, or parts of the channel periphery may not be coated.

  Both a small dimension of the device for reasons of energy loss and the possibility of operation of the device are decisive for the efficiency of the coupling. By use means the possibility of a defined implementation and operation with different flow rates

  i0 mass of educts respecting the specifications for the product flows of a reactor (possibility of modulation).

  The device is made up of several flat layers of material. The layers of material are made of a metallic material or a plastic material; depending on the application, these layers can have different thicknesses. There will be a flow in a channel structure per layer of material. The layers are made fluid tight vis-à-vis the outside. The pressure range of the reactor is, for reasons related to the material, preferably less than 50 bars of internal pressure relative to the outside. It is certainly possible to envisage generally higher pressures but in this case it is necessary to ensure the sealing in

  surface of the reactor, for example by welding or surface diffusion brazing to better absorb the significant forces between the different layers of sheet metal.

  The reactor according to the invention can be used in particular to couple two veins of reactive fluids, to couple a vein of reactive fluid and a vein of heat exchange fluid, the two veins of educts being able to be added in a metered manner and finally to couple a vein of reactive fluid to which is added, by dosing and under defined conditions, a vein of educts, with a process step for exchanging cha30 their for example for the coupling of a vein of fluid absorbing the heat with a stream of fluid in which one or more runs

exothermic reactions.

  The reactor according to the invention improves the concepts of existing integrated reactors by optimizing the calorific intake by dosing at least one fluid in at least one process stream, with reaction, to appropriately influence the temperature field in the reactor. The expression “temperature field” designates the evolution of the temperature in the material of the wall of the reactor and in the fluid channels in the three directions of space. This allows the process to be carried out successfully between two spatially separated reaction systems, which thus becomes only possible for many applications. In addition, the selectivity of the various reaction systems is improved by precise temperature control. In addition, a high power density is guaranteed for the heat capacity transmitted (both for applications with heat exchange requiring a high power density and for heating / cooling systems

  reaction with strong reaction enthalpy).

  In addition, the reactor according to the invention can be used to form explosive mixtures by the addition by metering of a vein of educts in a channel structure while guaranteeing the characteristics

  heat exchange which is ensured only inside the reactor.

  This improves safety for technical syntheses, for decentralized or mobile applications with an appropriate design of the

channel structures.

  Figure 1 is a top view of a reactor 10 according to the invention. Its construction and operation will be described below in application to the example of thermal integration for reforming to the value of methane. The endothermic reforming reaction with the educts CH4 and H20 (reforming gas) is coupled to the exothermic combustion of a combustion gas which is in the present case for example a CH4 / 02 mixture. In the fluid distribution range 11 the reforming gas 13 is distributed each time in a corresponding channel structure of a layer of material 12, other than that of the combustion gas 14 so that the reforming gas 13 and the gas 14 are passed through channel structures in different planes of the reactor. The planar construction by layers of the reactor using several layers of material 12 in different planes follows from FIGS. 2 and 3 which will be described in more detail below. The two fluids react in their respective channel structure, separated from each other, preferably by heterogeneous catalysis; thus the reactions take place on the surfaces of catalytically coated walls because the plate reactors, in particular for reactions of highly tinted walls from the thermal point of view, are applied by using the fact that only the thermal conductivity through the partition limits the heat exchange between the two structures of

  channel. In principle, however, one can also have homogeneous reactions.

  Figure 1 shows a parallel current guide of the two fluids 13, 14, which means that the two fluids are introduced on the same side of the reactor; in this case it is the fluid distribution range 11. But it is also possible to envisage a counter-current line according to which one fluid arrives in the fluid distribution zone 11 and the other fluid in a second distribution zone. planned fluid distribution

  at the end of the reactor opposite the fluid distribution zone 11.

  As is the case for the top view of the reactor according to the invention, only a channel structure appears composed of channels 15, parallel, Io into which the reforming gas 13 is introduced according to the present embodiment. channels which conducts the second fluid (in the present embodiment it is combustion gas 14) is provided in the plane under the channel structure 15 parallel to it as indicated by the arrow. The fluid distribution range 11 continues with the reaction range 16 proper in which, according to the present embodiment, there is the exothermic combustion of the combustible gas 14. In the present embodiment of the reactor according to the invention , there will be in this range 16 of the group of channels in which the exothermic reaction takes place, another educt (fluid) 22 which will be

  added by dosage. It is in particular for this other fluid a reaction partner; in the present case, it is for example oxygen.

  Depending on the conditions chosen, another fluid can also be added by dosage. The supply is made by the transverse channels 17 installed perpendicular to the channels 15. In these transverse channels the fluid added by metering is introduced via a common supply 18. The transverse channels 17 are provided between the

  planes in which the reforming gas 13 and the combustible gas 14 pass.

  In the present exemplary embodiment, the transverse channels 17 occupy the entire channel structure 15 and the corresponding channel structures that are placed below; the supply 18 takes place outside of this structure. It is also possible to arrange the entire guide 18 directly in the channel structure. This range 16 continues with a fluid collection range 19 in which the two streams of fluid are combined and removed from the reactor. In the case of a fluid line counter-current for the two fluids, this zone constitutes at the same time the range of fluid distribution for the first fluid and

  the fluid collection range for the second fluid. Correspondingly

  it dantes, the fluid distribution range for the second fluid is the same

  time the fluid collection range of the first fluid.

  FIG. 2 is a section along A-A of FIG. 1 which explains the structure by plane layers of the reactor formed from several layers of material 12. In the present example, these are two layers.

  In the present exemplary embodiment, the combustible gas 14 is guided in the upper channel structure 20 (oxidation channel) and the reforming gas 13 in the lower channel structure 21 (reforming channel). The two channels can have a different geometry. Between the two channel structures 20, 21, there are transverse channels 17 (in FIG. 2, perpendicular to the plane of the drawing) traversed by the fluid to be dosed. The metering is done by a metering structure 23 parallel to the respective channel structures, that is to say perpendicular to the

  transverse channels. In this metering structure, it is preferably perforated films 23, flat, parallel to the layer of material 12.

  For metallic devices, this sheet may be made of metal or of a thin metal sheet, suitably machined. Next to the range of

  reactor temperatures, plastics, porous ceramics or composite materials can also be used in principle.

  Combinations of these materials can also be used such as, for example, metal as the base material and plastic as a material for films. The increase in the section in Figure 2 explains this arrangement. The two layers of material 12, 12a are produced as already indicated above in a metallic material or a plastic or ceramic material. It should be noted that the two layers of material can also be different materials, for example different metal alloys. In addition, the materials can in principle

  have different sheet thicknesses and geometries.

  The upper layer of material according to FIG. 2, which guides the combustible gas (oxidation channel), has in the current embodiment a section smaller than that of the lower material layer through which the reforming gas passes ( reforming). The two layers of material can be separated in a fluid-tight manner by layers of metal or plastic. Sealing is preferably carried out by laser welding so that no particular sealing material has to be passed through. The educts crossing the corresponding channels and which are introduced in this example on the left side of the structure, that is to say in the fluid distribution zone in the reactor, pass through during their passage through the respective channel structures, the transverse channels 17 (these are installed perpendicular to the plane of the drawing) and from there the fluid added by metering is introduced into the oxidation channel via the perforated film 23 as indicated by the curved arrow. On the side opposite the fluid distribution zone, the products from the oxidation or reforming channel are led to the fluid collecting zone (reference 8 in FIG. 1)

to be extracted from the reactor.

  Figure 3 is a section of two layers of material of the 1o reactor according to the invention along the line BB of Figure 2. In this figure we have clearly shown the construction of the respective material layers 12 of a metallic material or a plastic material 25 and the channels 20, 21 produced in these layers. Figure 3 further shows that the two layers of material 12 have different geometries. Between the two layers of material there is the metering structure 23 in the form of a perforated film through which the fluid which is added by metering is introduced into the corresponding channel from the transverse channels 17 (shown in broken lines in Figure 3 because hidden by the respective layers of material). Advantageously, and as shown in FIG. 3, the channels 20 are integrated into the layer of material which

  leads the fluid vein into which there is no addition by dosing. (in the present embodiment it is the reforming channel).

  FIG. 4 schematically shows an example of production of the metering structure in the form of a perforated film 23; Figure 4 is a view along line C-C of Figure 3. The size and the number of perforations of the film 23 depend on the position. In this way, it is possible to introduce the added fluid by dosing at different points and in different concentrations into the corresponding ca30 nal structure; you can influence the fluid as desired

  passing through this channel structure.

  The distributed metering is designed to influence the thermal input of the combustion reaction for at least one operating point of the reactor. For this, provision is made here by way of example for the distributed supply of a large part of the oxygen required which may also be oxygen from the air via the transverse channels. Ideally,

  just before the end of the reaction range (reference 16, figure 1), the time

  The temperature of the material of the reactor wall does not drop significantly. The start-up of the reactor is facilitated by the distributed reaction of a gas stream containing hydrogen and which ignites easily: for this, in the fluid distribution range (reference 11 in FIG. 1) of the oxidation channel, using an electrical ignition source, either a gas stream containing hydrogen is heated, or a gas stream containing hydrogen is generated, for example by catalytic decomposition d '' a gas containing a hydrocarbon on a hot lo surface. The black smoke that is deposited on the surface of the source

  Ignition will be burnt during the subsequent metering of a hydrocarbon / oxygen gas mixture at the ignition source.

  The axial reaction of the hydrogen-containing gas stream can be assisted by a precise supply of an oxygen-containing oxidizing agent through the transverse channel structure 17 as described. The gas stream containing hydrogen, heated by the ignition source, is then used so that the temperature of at least one partial zone of the reactor decreases sufficiently so that the combustion reaction of a mixture of methane follows.

  could burn with a stream of oxygen-containing gas.

  The design of the transverse channels used for dosing

  is preferably chosen so that the pressure drop in the transverse channel is not significantly lower than that of the metering structure. This allows precise dosing of fluid to be achieved by the dosing structure in the channel structure, through which the reactive medium passes.

  The pressure loss in the transverse channel or in the dosing channel (the dosing structure is not necessarily composed of transverse channels) will be compared with the pressure loss in the dosing structure, for example the film 23, to be maintained at a level sufficiently low for the section of the channel in the channel structure 17 to be significantly greater according to the rules known in the art than the free section of the perforated film or of the perforated metering structure. At the same time or as a variant, it is possible to choose the supply of the educt vein added by dosage so that the fluid added by dosage changes along the channel. This is ensured in that the supply and distribution of fluid between the transverse channels is subdivided into several zones into which each time another fluid is introduced by metering. Each of the zones thus has its own supply of metering fluid (reference 18 in FIG. 1). As with the addition by metering of a single fluid, it is also possible to join the transverse channels of a metering structure already in the channel structure. The construction of each dosing structure is significantly simplified for the distribution of fluids. Another application of the reactor according to the invention is the coupling of two reacting fluid streams into which another mixture of educts is added each time. This can be done in the following using the example of the injection of reaction enthalpy of a vein of exothermic reaction gas to heat and / or guarantee the transition of

  phase of a second fluid which will be detailed below.

  A membrane fuel cell and polymer electrolyte,

  the hydrogen arriving from the anode side cannot be completely converted.

  The outlet gas stream from the hydrogen-containing anode must be separated from hydrogen and methane before being discharged to the environment for both energy consumption and safety reasons. A frequently applied concept for the use of anode outlet gases is the catalytic conversion of this gas. The hydrogen content makes it possible to ignite the reaction already at low temperatures. Of

  made of the coupling of a strongly exothermic reaction with a strongly endothermic vaporization operation, in conventional evaporators, there is the requirement to introduce and distribute the heat regularly.

  In the sense of the reactor of the invention, the gas stream containing hydrogen can be supplied in a distributed manner through the transverse channels and the oxidizing agent will be metered at the start of the channel. As a variant, it is also possible to envisage dosing the oxidizing agent through the transverse channels and dosing the anode outlet gases containing hydrogen in the fluid distribution range 18 of the channel. By an appropriate partition of the perforation, a conversion can be carried out

  full of hydrocarbons and hydrogen in the channel.

  By a suitable temperature pipe and a selection of the material, the reactor according to the invention can not only ensure vaporization but also respond to the overheating of the gas / vapor mixture obtained. This concept is particularly suitable for the vaporization of the carrier gas of weak hydrocarbon; the evaporator will receive as educt at

  spray a mixture of oil and liquid, at least water.

  To reduce irregular evaporation, it is possible to envisage an embodiment in which the liquid to be vaporized arrives at the inlet of a channel to be then mixed with the metered hydrocarbon through a separate perforation

during evaporation.

  The metered addition as described of two different fluids in each time a channel structure is shown in Figure 5. The starting point is the variant in which two different auxiliary veins are added by dosage through the perforated wires. The carrier gas for the vaporization is supplied in a distributed manner to the channel structure 27, i.e. the carrier gas is added by metering to vaporize the

  along the canal and the addition by metering thus ensures a mixed function.

  To heat the evaporator, a combustible gas containing hydrogen and / or hydrocarbons is metered into the second channel structure 28 as described above, passing through the transverse channels 17 (this is shown in dashed lines at Figure 5), this ali15 ment being dosed. To allow a simple symmetrical extension by paralleling the pipe of the fluid streams in the reactor according to the invention, other dosing structures have been shown 26, 29

  comprising the channel structures or channel structures 27, 28.

  Another example of a use of the reactor as proposed is that of the selective oxidation of CO to C02 in the operation of fuel cells with membrane and polymer electrolyte with

  a gas stream containing hydrogen obtained from hydrocarbon.

  In addition to a high catalyst activity and a selectivity in the conduct of the process, which are decisive for a high conversion of CO and a high selectivity for a attenuated course of the auxiliary reaction H2 + 0.5 02 -> H2O. The control of the process here especially gives a supply as defined as possible of the oxidizing agent and an extremely precise temperature control. A minimum temperature is required to allow CO oxidation and a maximum temperature, which is slightly above 20 ° C, must not be exceeded for

  avoid annoying accessory reactions of hydrogen oxidation.

  The conventional methods working in the low power range and which have been developed at present, in particular for fuel cell applications, use monolithic structures to carry out the reaction. Thus, the reaction is generally carried out in two separate reactors between which there is an intermediate cooling step. The dosage of an oxygen-containing gas is done

  so upstream of the respective reactor and in part we even regulate separate-

  a global gas stream containing oxygen upstream of the various reactors.

  The even distribution of the oxygen-containing gas stream in the monolithic structure is only a more difficult challenge to solve. In addition, it is not possible to guarantee the execution of the process by the formation, if necessary, of local mixtures, liable to explode, at the place where the mixing takes place. The temperature control for selective oxidation has several drawbacks in the current implementation of decentralized prototype installations. On the one hand, the adaptive means are relatively high because it is necessary to execute two reaction steps and a heat exchanger function, thermally, practically without integration. On the other hand, independently of the constructions to be implemented, there are the drawbacks of imprecise temperature control. The consequences can be damage to the catalyst due to overheating, insufficient conversion rates, insufficient selectivity of the process and in the extreme case runaway reaction due to the reaction and exchange zones of

separate heat in space.

  The integration of an efficient heat exchange with an ad20 defined, defined junction, distributed of the oxidizing agent according to the reactor as proposed here, offers numerous advantages from the point of view of the regular conduct of temperature and high conversion. The fluid stream in which the oxygen-containing gas stream is metered through transverse channels, is constituted in this application by the gas / vapor mixture containing hydrogen from the

reforming process.

  The process safety is significantly increased if sufficiently small structures are chosen which guarantee good heat dissipation by an appropriate design. In addition, the risk of explosion is very largely eliminated because, by using the principle of the reactor as presented, the mixing between the oxidizing agent and the reformate stream, containing hydrogen, takes place directly in the reactor. Mixtures with explosive concentrations are only formed inside the device. For this suitable design, there is a risk of explosion because the risk of heating is limited by the transfer

  of heat in the material of the wall.

  If necessary, in addition to the distributed dosage of the product,

  remove heat from selective oxidation by at least one other structure

  channel ture. This structure preferably has only a heat exchange function so that it has no catalytic coating.

  However, for identical or analogous applications, it is also possible to provide a catalytic coating in which one or more endothermic reactions can take place. There is another example of the use of the reactor according to the invention in the combustion of a mixture of synthesis gas containing hydrogen to supply energy for an endothermic reaction which takes place in another channel structure. In one of the two channel structures, a mixture of hydrogen-containing gases is burnt. The oxidizing agent is supplied in a distributed manner to achieve regular release of the heat of reaction. The distributed dosage of the oxidizing agent avoids two difficulties. On the one hand, the formation of explosive mixtures is avoided before entering the reactor because the mixture is only formed inside the reactor and, on the other hand, the release of heat is distributed over the entire the length of the reactor, regularly thanks to an appropriate design. This considerably reduces the known difficulty of excessive temperatures in the entry zone of a catalytic range for reactions at extremely rapid speeds.

  like those of hydrogen oxidation.

  The reactor according to the invention makes it possible to couple highly exothermic process steps to highly endothermic steps in a device, effectively by increasing the degrees of freedom by precise dosing of the fluid in a ca25 nal structure. The dosing of fluids, which is more precise than in currently known devices, makes it possible to improve the defined temperature control in compact devices in which at least one reaction takes place. From the advantages relating to the addition, dosed in a flexible manner, of a flux of educt, allows the reactor according to the invention for the first time to mix explosive media, directly at the place of

  the reaction with simultaneous integration into heat exchange functions.

  For many applications, there are advantages over devices in which the energy coupling is done for example by external combustion reactions and devices in which there is no local dosage of an educt in the fluid stream or one or more local dosages. Compared to these, the advantages are in particular those of a locally very flexible design and simple to

  from the manufacturing point of view for dosing.

  Other advantages of the invention are, on the one hand, those linked to the integration of several process steps generally combined in a device as well as those linked very particularly to the proposed implementation of the distributed dosage of the reactant. It is therefore assumed that, according to the current state of chemical engineering, the first advantages will be used in the first place by the reactor according to the invention in numerous systems.

of reaction.

  The advantages of integrating several process steps into a device include, for example, better use of the reaction enthalpy of an exothermic reaction system to heat a generally endothermic reaction system. This decreases the achievement of efficient heat recovery in connection with the area of distribution / combination of fluids in the flow.

  enthalpy of the heat released which is not optimally usable from an energy point of view.

  Another advantage is that of the compact realization of the process function by the integration of several partial process steps. Besides the reduction in overall dimensions linked to a design of the channel structure in order to optimize the heat or material exchange operations according to the rules known in the art, there is in particular the advantage of a reduction in the heat losses thanks to a greater compactness of the device. While in industrial processes of large sizes, due to the large material flows, it is not possible to have sufficient precision of an adiabatic behavior of the device, this is often not the case in the fields of application described here. . The concept presented further allows in principle to subdivide the feeds of the transverse channels into different segments in the direction

channels.

  The advantages linked in particular to the proposed implementation of the distributed dosage of the educt are for example those of less expensive constructions to be carried out for a dosage of educt distributed locally in two dimensions as well as in greater freedom of the level

  of the metering volume flow thanks to different diameters of the perforations of the metering structure.

  There is also the advantage of improved operation because when the device is started up, it is possible to heat it up.

  much more regular fage. The transverse channels allow for example to distribute a mixture of educt, regularly in the reaction range to react catalytically with a second educt which crosses the channel structure while giving off heat. Operation can be completely discontinued during the start-up phase. There are other advantages linked to the absence of strong temperature gradients in the reactor in the start-up operation. High temperature gradients can lead to unacceptable stresses in the active material, in particular the bursting of the catalyst layers. Microreactors as an example of particular compact reactors are known to guarantee the conduct of the process and also for applications to potentially explosive gaseous components, thanks to their good heat transport characteristics. Thanks to the embodiment described here of a distributed dosage of the educt, the potential of a compact reactor is even more increased compared to the known embodiments because thanks to this new possibility of a defined and distributed combination for two educts by dosage of an educt in a reaction channel, controlled at the site of the reaction, there are new perspectives for process design. In addition, it is possible to stagger the in20 integrated device by paralleling the line of the fluid veins (a

  channel group consists of a number of channel structures depending on the operating conditions).

  The geometry of the reactor as presented offers the possibility of a distributed mixture of the educt, for example also advantageously if in the chosen temperature range there are very rapid reactions because the reaction zone can be distributed more regularly

  in two dimensions than with known methods.

Claims (8)

CLAIMS) Integrated reactor (10) having at least two channel structures (20, 21) separated in space to guide at least two streams of fluid, with in at least one stream of fluid within a range of reaction (16) a reaction which produces a variation in temperature and at the same time a transfer of heat between the veins of fluid, characterized in that at least one of the two veins of fluid receives in a metered manner, at least one other fluid distributes throughout the reaction range (16).   2) Integrated reactor according to claim 1, characterized in that   it (10) is formed of several layers of material (12) in parallel.   30) Integrated reactor according to claim 1, characterized in that the fluid added in a metered manner is supplied by transverse channels   (17) perpendicular to the direction of flow of the fluid veins.   40) Integrated reactor according to claim 3, characterized in that the transverse channels (17) are integrated in the layer of material (12) which conducts the fluid stream and in which another fluid is not metered. ) Integrated reactor according to claim 1, characterized in that   the metered addition of at least one other fluid into the corresponding channel structure is carried out by a metering structure (23).   ) Integrated reactor according to claim 5, characterized in that   the metering structure (23) is flat and arranged parallel to the layers of material (12).   ) Integrated reactor according to claims 5 or 6, characterized in that   the metering structure (23) is a film provided with perforations.   ) Integrated reactor according to claim 7, characterized in that   the film is made of metal or plastic.   90) Integrated reactor according to claims 7 or 8,   characterized in that the size and number of perforations is variable depending on their local position on the film.   10) Integrated reactor according to claims 5 or 6, characterized in that   the metering structure (23) is a porous ceramic structure.   11) Integrated reactor according to claim 3, characterized in that the pressure drop in the transverse channels (17) is less than that in the dosing structure (23).   ) Integrated reactor according to claim 1, characterized in that   the fluid added by metering is variable along the reaction range (16).   ) Integrated reactor according to claim 12, characterized in that   the supply of fluid added by metering is distributed between several zones along the reaction range (16).   ) Integrated reactor according to claim 1, characterized in that   at least one channel structure (20, 21) has a catalytic coating.   ) Integrated reactor according to claim 1, characterized in that the channel structures, separated from each other, have different geometries. ) Method for precisely conducting a reaction in an integrated reactor having at least two channel structures separated from each other in space to conduct at least two streams of fluid, in at least one stream of fluid to the within a reaction range, a reaction modifying the temperature and at the same time a heat transfer between the fluid valves, characterized in that at least one of the two fluid streams receives in a distributed manner in   the entire reaction range at least one other fluid added in a dio sized manner.   17) Method according to claim 16, characterized in that the fluid added in a metered manner is supplied by transverse channels perpendicular to the direction of flow of the veins of fluid, and at least this vein of fluid receives the fluid metered by the intermediary of a   flat dosing structure with perforations.   18) Application of the integrated reactor according to one of claims 1 to 15,   to evaporate in an energy efficient way and for the   overheating of mobile and stationary fuel cell systems.   ) Application of the integrated reactor according to one of claims 1 to 15,   for the selective oxidation of carbon monoxide in fuel cells.