DE10033596A1 - Device for carrying out a solid-catalyzed reaction - Google Patents

Abstract

An apparatus for carrying out a solid-catalyzed reaction, in which at least one educt is present in the liquid state under normal conditions, is created, which comprises a catalytic unit which contains an evaporation unit and a reaction unit which are in heat-conducting communication with one another, the evaporation unit being movable relative to the reaction unit is arranged. The evaporation unit can be arranged on the entire surface or only on a region of the surface of the reaction unit. Such a device is used, for example, in the hydrocarbon reforming reaction to obtain hydrogen.

Description

The present invention relates to a device for through Conducting a solid-catalyzed reaction with the Merkma len of the preamble of claim 1.

Solid-catalyzed reactions are currently becoming increasingly important in a wide variety of areas, for example in the field of fuel cells, hydrogen generation from hydrocarbons, which conventionally includes alcohols, aldehydes, ketones and the like, and water, which is known as hydrocarbon reforming (Ullmann's Encyclopedia of Technical Chemistry Volume 12 , pp. 113-136, Verlag Chemie, Weinheim 1976 ). Here, a mixture of the hydrocarbon, in particular methanol, and water is reacted on the surface of a corresponding solid catalyst, which usually contains copper.

Other examples are the conversion of carbon monoxide into Carbon dioxide by reaction with hydrogen in the so-called "Hydrogen shift reaction", the carbon monoxide oxidation, at which is a CO-containing gas with an oxygen-containing gas reacted with a catalyst and burning (oxidizing) a combustible educt with the addition of an oxygen-containing one Gases in a so-called "catalytic burner".

The fuel cells mentioned above are also increasingly being used in Motor vehicles used and win the combustion necessary hydrogen from the carried in liquid form Hydrocarbon, in particular methanol being used.  

In practice, this reaction is carried out so that a water Mixture containing steam and hydrocarbon under heat brought into contact with a suitable catalyst is used in a mostly multi-stage reaction process To produce hydrogen.

The liquid educts must either be finely atomized Catalyst surface are supplied or at least partially present in the vapor phase before they start with the Kata come into contact with the analyzer surface. The latter variant can be realized using different devices become.

DE 44 26 692 C1 is a so-called reforming freak Tor known in which the catalytically active layer Evaporator device is spatially separated where in heat transfer from evaporator to catalytically effective Layer takes place over a fluid heat transfer medium. The structure is complex, however, especially by using a additional heat transfer medium.

Next is in DE 197 20 294 C1 and the unpublished Patent application DE 199 06 672.8 with a reforming reactor an upstream coupling of the evaporator and reaction gas ne described. The evaporator consists of a porous sen, thermally conductive structure attached to the reaction zone, d. H. the catalytically active layer, adjacent and with this is rigidly connected. This can be done through a common sin tern of the evaporator structure with the catalytically active Layer happen so that the coupling of the thus produced Reaction zone is integrally formed with the evaporator. The heat is transferred via solid-state heat tung.

The rigid reactor reactor systems discussed above Show bond or coupling of the evaporator and reaction zone However, the disadvantage is that the liberated during evaporation  Heat due to the resulting thermal gradient between evaporator and reaction zone mechanical, thermal induced voltages, or "thermal voltages" for short, in the reactor onszone. This often leads to breaks and discard in the physical structure of the reaction zone, however also on the evaporator structure, which even flake off partially can.

Proceeding from this, the invention is based on the object to create a coupling between the evaporator and the reaction zone fen, the above disadvantages of the prior art Technology avoids and insensitive to thermal voltages is.

This task is carried out by a device for carrying out egg ner solid-catalyzed reaction with the features of the An spell 1 solved.

Due to the movable arrangement of the evaporation unit ge voltages occurring in relation to the reaction unit Translated and derived translation energy so that the Structures of both units remain unaffected by this and there no damage, such as cracks, faults and Ablations, carry away.

In this context, the term "flexible" means each Arrangement understood that the evaporation unit before are of temperature gradients between evaporation and Re action unit enables translation movements relative to To perform reaction unit which the thermal voltages in Transfer kinetic energy. This can be done, for example can be achieved by using a metal fleece as the evaporation unit is selected, which by suitable means on the reaction unit is movably attached. Likewise, the evaporator unit also made of sintered ceramic or sintered metal leads, which is then mechanically or by pressing on the Reaction unit is attached.  

The arrangement from evaporation area to reaction area is freely selectable, as long as a solid-heat conductive connection exists, d. H. the evaporation area can be according to DE 197 20 294 C1 arranged above or next to the reaction area his.

The evaporation unit is advantageously porous, so that the starting materials can reach the reaction unit in a controlled manner NEN. Depending on the pore size and possible pressurization can then be the amount of starting materials that are supplied to the reaction unit arrive, be dosed so that the reaction can be optimized can. Of course, the use of a metal fleece is also included for example made of stainless steel or a suitable alloy, conceivable, but here the often too large width of the Ma be considered.

In a preferred embodiment, the evaporation unit is on arranged over the entire surface of the reaction unit. because is a uniform heating of the reaction unit guaranteed. This is still beneficial if the reak tion mixture through the evaporation unit and the often also porous reaction unit is pressed.

However, it is also advantageous to egg the evaporation unit To arrange a portion of the surface of the reaction unit NEN. This is particularly preferred when the reactions products, as in some cases, by evaporation and Reaction unit are pressed, but if they by means of me Chanian devices only to an area with the Ver vaporization unit-covered reaction unit can be added should. However, this depends on the choice of reactor and the catalytic reaction. For example, it is also think bar that a modular so-called stack reactor several sequentially arranged catalytic units consists of reaction units which alternate regularly or irregularly  have at least partially on the surface as an evaporation unit is arranged.

According to a preferred embodiment of the invention Devices are several stacked catalysis units are provided, the shape of which is freely selectable. Every kata lysis unit has at least one breakthrough, the respective breakthroughs to form an input channel for Feed of the educt mixture are aligned and between Ver. branches off the individual layers from the input channel dividing channels are formed. The reaction mixture is now led to the surface of the evaporation units, wherein the required heat of vaporization through an exothermic reaction the liquid or, if necessary, by adding an additional Lichen fuel, such as oxygen. The Reaction mixture now reacts at the reaction unit and if necessary occurring thermal voltages, e.g. B. too fast ler supply of the reaction mixture, are by the opposite the evaporation unit movably arranged in the reaction unit derived in translation energy, so that also expensive built stacked reactors without damage by thermal voltage can be operated longer.

Of course, other concepts are also special of modular stack reactors where the Invention can be realized.

A device according to the invention is used at kata lytic reactions in which at least one reactant is in liquid form, which is usually exothermic solid-state analytical reaction in a reactor in the steam or gas state must be transferred. A preferred example is the production of hydrogen from a mixture of a hydrocarbon and water as defined at the beginning.

Further advantages and refinements of the invention result itself from the description and the accompanying drawing.  

It is understood that the above and the following standing features to be explained not only in each specified combination, but also in other combinations or can be used alone, without the scope of to leave the present invention.

The invention is based on an embodiment in the Drawing is shown schematically and is below Described in detail with reference to the drawing.

Fig. 1 shows a cross section through a device according to the invention.

Fig. 2 shows a cross section through a further device according to the Invention.

In Fig. 1, a catalysis unit 1 is shown, which consists of egg ner evaporation unit 2 and a reaction unit 3 be. In this case, the evaporation unit 2 is arranged on the entire surface of the reaction unit 3 so as to be movable relative to the solid body in a heat-conducting manner. The catalysis unit 1 also has at least one opening (not shown in the drawing).

The surface of the catalysis unit can be freely structured the, for example in the form of meandering surveys Enlargement of the reactive surface both when evaporating as in the reaction process. Act in the present case however, it is essentially one for simplicity flat surface.

The evaporation unit 2 comprises a porous, thermally conductive body with a large wettable surface, which is optionally overflowed by a gaseous oxidizing agent, for example air or oxygen. The reaction unit 3 consists of a preferably sintered, porous, catalytically active material containing gas-permeable body. In another embodiment, the reaction unit 3 on its underside can also be made gas-impermeable by suitable measures.

The evaporation unit 2 is either pressed onto the reaction unit 3 , the contact pressure being selected so that when thermal stresses occur, the evaporation unit 2 can move relative to the rigidly fixed reaction unit 3 , or else by suitable mechanical means, for example frames, grooves, Clamps and the like, arranged on the Reakti onseinheit 3 movable solid-state heat.

The liquid to be evaporated is supplied to the surface of the reaction unit 2 in the sense of the arrows shown in the figure. The necessary evaporation energy is provided by an exothermic reaction of a fuel with which the oxidizing agent on the catalyst material diffuses into the evaporation unit 2 and into the reaction unit 3 . The fuel, which can also be the liquid to be evaporated itself, can be in liquid as well as partially or completely in vapor or gaseous form.

Depending on the type of reactor, the resulting gas is either in the Evaporation unit is returned and is together with the any oxidizing agent required from the reactor dissipated. In case, however, it is a modular one Stack reactor of the type in which the reaction educts together with any necessary oxidizing agent all catalytic units arranged one on top of the other are pressed, the educt mixture is reacted over all catalysis units and the products are only on taken from the lower end of the stacked reactor.

Fig. 2 shows a catalysis unit 6, which also consists of an evaporation unit 7 and a reaction unit 8.

In this case, the evaporation unit 7 is arranged on a part of the surface of the reaction unit so as to be movable in a solid-state heat-conducting manner. The materials of the reaction and evaporation unit correspond to those described above under FIG. 1. Likewise, the movable arrangement of the evaporation unit 7 on the reaction unit 8 takes place with the measures described above.

As described under FIG. 1, the educt mixture is evaporated in the evaporation unit 7 . The mixture of starting materials, products and an oxidizing agent which may be necessary is then passed in the direction symbolized by the arrows onto the surface of the catalytic unit 8 not covered by the evaporation unit 7 , where the starting material mixture continues to react. The conversion of the educt mixture is faster, but less controllable.

The person skilled in the art makes the choice between the concepts of the device according to the invention shown in FIGS . 1 and 2, depending on the reaction to be carried out and the type of reactor used.

Claims (5)

1. An apparatus for carrying out a solid-catalyzed reaction, in which at least one educt is present in the liquid state under normal conditions, comprising a catalytic unit ( 1 ) which contains an evaporation unit ( 2 ) and a reaction unit ( 3 ) which are connected to one another in a heat-conducting compound, characterized in that the evaporation unit ( 2 ) is movably arranged with respect to the reaction unit ( 3 ). 2. Device according to one of the preceding claims, characterized in that the evaporation unit ( 2 ) is at least partially porous. 3. Apparatus according to claim 1 or 2, characterized in that the evaporation unit ( 2 ) on the entire surface of the reaction unit ( 3 ) is arranged. 4. Apparatus according to claim 1 or 2, characterized in that the evaporation unit ( 2 ) is arranged on a partial area of the upper surface of the reaction unit ( 3 ). 5. Device according to one of the preceding claims, are provided by in that a plurality of stacked Ka talyseeinheiten (1) each having at least ei NEN breakthrough to form a channel, and wherein the stacked catalytic units (1) spaced from each other are arranged.