DE10063647A1 - Reactor used for carrying out steam reforming of methanol has an active zone with a first temperature zone for introducing the heat of reaction separate from a first reaction zone for carrying out the reaction - Google Patents

Abstract

Reactor comprises reaction chambers (R1, R2, ...Rn) for converting educts (E); and temperature regions (H1, H2, ....Hn) for introducing or removing the heat of reaction to or from the educts. An active zone is arranged along an educt flow path (S) between an inlet (1.1) and an outlet (1.2) of the reactor. The active zone has a first temperature zone (H1) for introducing the heat of reaction separate from a first reaction zone for carrying out the reaction. Preferred Features: Further temperature zones and reaction zones follow in the active zone along the educt flow path to the first temperature zone and the first reaction zone. The temperature zones directly heat the educt stream by catalytic combustion.

Description

The invention relates to a reactor according to the preamble of independent claim.

DE 197 13 242 A1 discloses a reactor which is used for Steam reforming of methanol in Fuel cell vehicles can be used. The reactor is designed as a stack arrangement in which a variety of parallel flow through catalyst-containing reaction spaces are separated from each other by boiler rooms, which the Reaction rooms with heat to maintain the endothermic Provide reforming reaction. The heat in the boiler rooms can by heat transfer media such. B. oil, or a chemical Response, such as B. catalytic combustion.

With such stack arrangements, especially with directly heated ones Reactors, there are very high demands on a good one Equal distribution of the media to be implemented between the individual reaction spaces as well as within the Reaction rooms where e.g. B. the risk of local overheating threatening. At the same time, the reform reaction is strong endothermic, so that a sufficiently large heat input from the Boiler rooms must be in the reaction rooms in the stacked reactor, and this as far as possible along the reaction pathways in the Reaction chambers.

As possible the implementation of the medium in the reforming reactor should be high, it follows that the reaction spaces to  must have the narrowest possible gap widths and others that a sufficient high number of reaction spaces must be available to a sufficient amount of Generate reformate. This in turn leads to Distribution problems of the media in the reforming reactor and too unfavorably high manufacturing costs as well as an unfavorable Ratio of mass to volume of the reforming reactor.

The invention has for its object a reactor to specify, with the lower requirements on the Equal distribution of the media are provided.

This task is carried out in a reactor with the characteristics of Claim 1 solved.

According to the invention, in the active area of a reactor Heat input into or heat removal from a feed stream of a chemical reaction of the starting material separately.

The particular advantage is that the reactor can be constructed in this way can that in the active area of the reactor targeted thermal influencing of the educt and chemical conversion of the educt to their special tasks can be optimized without the high degree of Implementation of the educt is deteriorated. The reactor structure is considerably simplified and cheaper.

It is understood that the above and the Features to be explained below not only in the combination given in each case, but also in others Combinations or alone can be used without the To leave the scope of the present invention.

Further advantages and refinements of the invention are based the further claims and the description.  

The invention is described below with reference to a drawing described, the figures showing:

Fig. 1 is a schematic representation of a preferred reactor Eduktströmungsweg,

Fig. 2 is a schematic representation of a further preferred reforming reactor with heating rooms and reaction rooms and

Fig. 3 is a schematic representation of a further preferred reforming reactor with heating rooms and reaction rooms, the cross-section through which the flow increases increases along the educt flow path.

The invention is favorable both for reactors in which a Educt is reacted through an endothermic reaction as well for reactors in which an educt is exothermic Reaction is implemented. In the following the invention is based described a preferred reforming reactor.

In Fig. 1 is a schematic representation of a preferred embodiment of a preferred reforming reactor 1 is shown. The reforming reactor 1 is used to reform a fuel which contains hydrogen, preferably methanol or other alcohols, ethers, esters, hydrocarbons.

According to the invention, along a reactant flow path S between an inlet 1.1 and an outlet 1.2 of the reactor 1, at least one first temperature zone H1 for supplying the heat of reaction is provided spatially separated from a first reaction zone R1 for carrying out the reforming reaction. The educt stream in the reforming reactor 1 is indicated by arrows.

The area between input 1.1 and output 1.2 is to be understood such that an educt to be converted enters at input 1.1 into an active zone of reactor 1 , in which it is converted and preferably leaves this area essentially largely converted by output 1.2 . So z. B. methanol through the inlet 1.1 into the reactor 1 , and through the outlet 1.2, a hydrogen-containing reformate leaves the reactor 1st The intermediate active zone in which the conversion takes place can be arranged in a common housing, but several components can also be arranged in different housings. The area between input 1.1 and output 1.2 is referred to as reactor 1 , which includes at least the active zone of reactor 1 , regardless of whether it is in a single housing or is divided into several spatially separated components.

The heat input into the educt stream E and the chemical reaction are spatially separated from one another within the active zone of the reactor 1 . The necessary heat of reaction is the educts before the respective actual catalytic area R2, R3, R4,. , ., Rn of the reforming reactor 1 supplied. With the educts E, this causes them to enter the respective reaction zones R2, R3, R4,. At a relatively high temperature. , ., Rn and there due to the endothermic reforming reaction along the respective section of the educt flow path S in the reaction zones R2, R3, R4,. , ., Rn cools down. A mixture of educts and products forms in the educt flow path S, the proportion of the products along the educt flow E increasing. To complete conversion of the starting materials to obtain, can the mixture of reactants and products several times in successive heating zones _{H1, H2, H3, H4,.} , ., Hn are heated and the respective catalyst-containing reaction zones R2, R3, R4,. , ., Rn fed, implemented there and cooled again.

In a conventional reforming reactor in preferred Panel construction according to the prior art are common two flow circuits, namely a flow circuit for the educt flow and a flow circuit for an active or passive heating medium available, the educt flow on the Educt / product side of the reactor continuously through catalytic apart from the active plates Distribution channels and / or collection channels with which the educt in the plate arrangement is distributed into or out of it Plate arrangement is led out. With a usual multi-stage plate arrangement is the educt flow through such Channels out of the previous stage and into the next Level.

According to the invention, S follows along the educt flow path the first tempering zone H1 and the first reaction zone R1 further temperature zones H2, H3, H4,. , , Hn and reaction zones R2, R3, R4,. , ., Marg. The entire heat input preferably takes place that for the partial reforming of the starting material in one Zone R1 is necessary in the upstream Temperature zone H1 instead. Then the educt / product mixture in the next tempering zone H2 back to a temperature heated, which is so high that the next part Reforming step of the educt / product mixture in the next Reaction zone R2 can run. This is repeated so many times until the desired degree of conversion of the starting material into a product is reached.

The advantage is that the temperature zones H1, H2, H3, H4, , , , Hn be optimally designed to heat the educt stream can. It is useful to determine the number of temperature zones H1, H2, H3, H4,. , ., To choose Hn so that the Temperature resistance of the catalyst in the reaction zones is guaranteed.

Along the educt flow path S can go to the first Temperature control zone H1 and the first reaction zone R1 further  Temperature zones H2, H3, H4,. , , Hn and reaction zones R2, R3, R4,. , ., Rn follow one another alternately.

Usually in the steam reforming of methanol used catalysts, in particular noble metal catalysts such as platinum, or catalysts with ruthenium, rhodium, etc. at least three temperature zones H1, H2, H3 and three Reaction zones R1, R2, R3 alternately in succession sufficient. Three to five such levels are favorable.

The reactor is particularly preferably designed as a stacked plate reactor. Along the educt flow path S in the reactor 1 , the active zone is essentially plates H1, H2,. ., Hn, R1, R2,. , ., Rn formed, the active zone as reaction zones R1, R2, R3,. , ., Rn has reactant-flowed plates with catalyst in which the reactant is converted and used as temperature zones H1, H2, H3,. ., Hn has educt-flowed plates without a catalyst in which the educt or the educt / product mixture is heated. Catalyst-containing plates and catalyst-free plates preferably follow one another alternately along the educt flow path S.

Because no more heat input into the catalyst-containing Area, preferably a catalyst bed, must take place, are the reaction zones R1, R2, R3, R4,. , ., Rn no longer in limited their gap width. Thus the number of Reformer rooms R1, R2, R3, R4,. , ., Rn can be reduced. there it is favorable to take a along the educt flow path S. same number of temperature zones H1, H2, H3, H4,. , ., Hn and Reaction zones R1, R2, R3, R4,. , . To provide margin.

In addition to the advantage that the number of reaction zones, preferably the number of plates in a plate reactor, can be significantly reduced, such a reforming reactor 1 according to the invention has less mass, a smaller volume and requires a significantly lower production outlay. The requirements for the uniform distribution of the educts and the heating media are lower than in a conventional arrangement.

It is possible to use one in the reaction zone R1, R2, R3, R4,. , , Rn to use fixed reforming catalyst preferably a monolithic catalyst body.

The reforming catalyst is at a uniform temperature level across the flow direction. A temperature gradient is therefore advantageously avoided. This also increases the life of the reforming reactor 1 , which is exposed to less thermal stress.

A preferred embodiment of a reforming reactor 1 according to the invention is shown in FIG. 2. The same elements are given the same reference numerals. The temperature zones H1, H2, H3, H4,. , ., Hn are designed as heat exchangers. A heating medium M flows through media rooms in the heating zones H1, H2, H3, H4,. , ., Hn and thereby heats the educt stream E through the heat exchanger device. The educt stream E has more and more reaction products, in particular hydrogen, along its flow path S. The flow path is through the arrows through the temperature zones H1, H2, H3, H4,. , ., Hn and reaction zones R1, R2, R3, R4,. , ., Rn indicated and consists of the individual sections in the reaction zones R1, R2, R3, R4,. , ., Rn of the reforming reactor 1 together. The direction of flow of the heating medium M is indicated by dashed arrows. The heating medium can be fed in parallel into all temperature zones H1, H2, H3, H4,. , ., Hn can be introduced, as indicated in the figure. Alternatively or additionally, each individual tempering zone H1, H2, H3, H4,. , ., Hn are supplied with a cardiac medium of different temperatures and / or a group of heating zones H1, H2, H3, H4,. , ., Hn with a heating medium M of the same temperature and other heating zones H1, H2, H3, H4,. , ., Hn with different temperatures. The heating zones H1, H2, H3, H4,. , ., Hn can advantageously optimally adapt to the reforming process to be carried out in the reaction zones R1, R2, R3, R4,. , ., Rn can be adjusted.

At the exit of the reforming reactor 1 , a product stream P finally emerges from the reforming reactor 1 and which can then optionally be fed to a gas cleaning system (not shown) of a fuel cell unit. Heating the heat exchangers of the temperature zones H1, H2, H3, H4,. , ., Hn can by a heating medium M, such as. B. hot gas or oil.

The temperature zones H1, H2, H3, H4,. , ., Hn can also for the direct heating of the educt stream E by catalytic Combustion trained. The heating medium M in the temperature zones H1, H2, H3, H4,. , ., Hn catalytic burns and so heats the educt stream or the mixture Educts and products. With such direct heating of the temperature zones H1, H2, H3, H4,. , ., Hn can local high Temperatures do not damage the catalytic converter, because before they enter the educt stream E into the catalyst bed of the educt stream is mixed.

The flow through the temperature zones H1, H2, H3, H4, , , ., Hn through the heating medium M with direct heating too take place serially so that a heating medium flow M one after the other through all temperature zones H1, H2, H3, H4,. , ., Hn flows. Conveniently, a fuel such as methanol is in the Air flow in the flow direction of the heating medium M before each or at least some temperature zones H1, H2, H3, H4,. , ., Hn  added, or in the temperature zones H1, H2, H3, H4,. , ., Hn dosed. For this, in front of or in the temperature zone H1, H2, H3, , , ., Hn a dosing agent for dosing fuel into the Educt stream E provided. An air flow forms at the Use of methanol as a fuel conveniently Heating medium flow M.

A favorable further development of the arrangement according to the invention is shown in FIG. 3. The arrangement largely corresponds to the arrangement in FIG. 2. The same elements are denoted by the same reference symbols. Along the educt flow path in the reforming reactor 1 , the composition of the medium changes, the amount of the educts, for. B. methanol decreases and the amount of products, e.g. B. hydrogen increases. The decreasing educt concentration in the reforming reactor 1 in the direction of the reactor outlet 1.2 leads to a slowdown in the chemical reaction rate. By separating temperature zones H1, H2, H3, H4,. , ., Hn and reaction zones R1, R2, R3, R4,. , , Rn, the reforming reactor 1 can be easily adapted to the reaction rate. If the reaction speed slows down in the direction of the reactor end 1.2 , the cross section through which the reaction zones R1, R2, R3, R4,. , , Rn along the educt flow path S can be increased accordingly to in the reaction zones R1, R2, R3, R4,. , , Rn to enable approximately equal residence times of the educt stream or of the mixture of educts and products.

The flow-through cross section of the reaction zones is favorable R1, R2, R3, R4,. , , Rn along the educt flow path S approximately inversely proportional to the reaction speed of the To increase the educt current.

By separating temperature zones H1, H2, H3, H4,. , ., Hn and reaction zones R1, R2, R3, R4,. , , Rn, the respective areas of the reforming reactor 1 can each be configured favorably for their respective task. This can be done locally differentiated along the flow path of the educt stream E and also along the flow path of the heating medium M, so that the individual reactor areas are well coordinated.

The invention can also be applied to reactors in which an endothermic but an exothermic reaction does not take place in the active zone between inlet 1.1 and outlet 1.2 of reactor 1 . In the temperature zones H1, H2, H3,. ., Hn along the educt flow path S, the educt is then cooled while it is in the reaction zones R1, R2, R3,. , ., Rn is brought to a high temperature by an exothermic reaction taking place there, preferably a selective oxidation or partial oxidation of, for example, carbon monoxide or a hydrogen-containing fuel. In order to prevent the exothermic reaction in the reaction zone R1, R2, R3,. , ., Rn use undesired further reactions, this reaction zone can be shortened accordingly and / or the catalyst coverage can be adapted so that an upper limit temperature for the use of such undesirable side reactions is not exceeded.

Claims (10)

1. Reactor for carrying out a reaction, the reactor ( 1 ) having at least one reaction space (R1, R2,..., Rn) for reacting starting materials (E) and at least one area (H1, H2,.., Hn) for supplying or removing the heat of reaction to or from the educts (E), an active zone (R1, R2,..., Rn, H1, H2,..., Hn) along an educt flow path (S) The inlet ( 1.1 ) and an outlet ( 1.2 ) of the reactor ( 1 ) are arranged, characterized in that the active zone has a first temperature zone (H ₁ ) for supplying the heat of reaction spatially separated from a first reaction zone (R1) for carrying out the reaction , 2. Reactor according to claim 1, characterized, that in the active zone along the educt flow path (S) the first temperature zone (H1) and the first reaction zone (R1) further temperature zones (H2, H3, H4,... Hn) and reaction zones (R2, R3, R4,..., Rn) follow. 3. Reactor according to claim 1, characterized, that the reaction zones (R1, R2,..., Rn) by Educt-flowed plates with catalyst and the temperature zone (H1, H2,.., Hn) through plates through which educt flows without Catalyst is formed.   4. Reactor according to claim 1, characterized, that along the educt flow path (S) to the first Temperature control zone (H1) and the first reaction zone (R1) further Temperature zones (H2, H3, H4,... Hn) and reaction zones (R2, R3, R4,. , ., Rn) follow one another alternately. 5. Reactor according to claim 1, characterized, that the tempering zone (H1, H2, H3,..., Hn) for direct Heating of the educt stream (E) by catalytic combustion is trained. 6. Reactor according to claim 5, characterized, that before or in the tempering zone (H1, H2, H3,..., Hn) Dosing agent for dosing fuel into the educt stream (E) is provided. 7. Reactor according to claim 1, characterized, that the flow-through cross section of the reaction zone () along of the educt flow path (S) increases. 8. Reactor according to claim 7, characterized, that the flow-through cross section of the reaction zone (R1, R2, R3,. , , Rn) reversed along the educt flow path (S) proportional to the reaction rate of the educt flow is enlarged. 9. Reactor according to claim 1, characterized in that the reactor ( 1 ) is a reforming reactor for reforming a hydrogen-containing fuel. 10. Reactor according to claim 1, characterized in that the reactor ( 1 ) is a reactor for the selective or partial oxidation of a hydrogen-containing or carbon monoxide-containing fuel.