WO2005046857A1

WO2005046857A1 - Device for carrying out liquid reactions with fine-grained solid catalysts and method for the use thereof

Info

Publication number: WO2005046857A1
Application number: PCT/EP2004/052202
Authority: WO
Inventors: Horst-Werner Zanthoff; Dietrich Maschmeyer; Thorsten SCHWÄRTZKE; Udo Robers; Anita VÖLKEL
Original assignee: Oxeno Olefinchemie Gmbh
Priority date: 2003-11-15
Filing date: 2004-09-16
Publication date: 2005-05-26
Also published as: EP1682256A1; DE10353391A1; TW200524673A

Abstract

The invention relates to a reactor (3) for carrying out catalyzed liquid reactions, whereby the catalyst is finely distributed in the reaction area(3). According to the invention, the reactor (3) comprises at least one inlet (1) and one outlet (2). All educts are supplied via the inlet and all products are discharged via the outlet. The inlet and outlet are provided with a means (8) enabling the inlet and outlet to be connected in such a way that an outlet can be used as an inlet and at the same time an exit previously used as an outlet can be used as input used for an inlet. A filter element (1,2) is provided on the inlet and outlet in order to retain the catalyst inside the reactor. A device is also provided in the reactor in order to ensure homogeneous distribution of the catalyst and educts in the reactor. Said reactor makes it possible to conduct reactions of the above variety with a high solid content without being obliged to separate the catalyst from the production flow in an extra procedural step and without regular cleaning and interrupting the process.

Description

Device for carrying out liquid reactants with fine-grained solid catalysts and process for its use

The present invention relates to a device for carrying out liquid reactions, in particular liquid-liquid or liquid-gaseous reactions, in the presence of fine-grained solid catalysts.

It is known that a large number of chemical reactions can be carried out at elevated pressure and with the addition of a dispersed or suspended catalyst. The fluid reactants can be supplied to the reactor in a liquid phase, in several liquid phases or additionally as a reaction gas. Examples of liquid reactions are: oligomerizations, methathesis, alkylations or isomerizations, and heterogeneous bio-catalytic reactions.

When carrying out such reactions, but also when determining the intrinsic reaction kinetics, the use of finely dispersed catalyst granules is preferred, since this allows the pressure drop to be minimized in comparison to a fixed bed reactor with catalyst pellets. In addition, pore diffusion inhibition is largely avoided due to the small particle size and in exothermic reactions there are usually no local temperature peaks as in a fixed bed reactor, since the fluidized catalyst leads to isothermal reactor behavior through convective mixing.

In the reactions, the solid catalyst is generally not consumed by the reaction leading to the product, so that the catalyst would not have to be removed from the reaction area.

For this reason, such suspension reactions are often carried out in such a way that the catalyst is retained in the reactor by sintered metal or ceramic frits, or by wire mesh constructs. The problem here is the build-up of a filter cake on these filter elements over time, particularly with a high solids content in the liquid, which impairs a uniform distribution of the catalyst and leads to reactor blockage. The filter cake cannot usually be built up by stirrers either be prevented. The reactor must therefore be shut down periodically and the filter elements cleaned.

In a variant of this process control, it was proposed to install a further filter element for gas-liquid reactions (hydrogenating reaction) through which the hydrogen is added (US Pat. No. 5,935,418). After a predetermined interval, a switch is made between the two filter elements, so that the reaction liquid is now removed by the H ₂ filter element and the hydrogen is now fed in via the outlet filter element. In this case, however, it is problematic to maintain an exact liquid level in the reactor because there are two independent inflows into the reactor. Such a principle is problematic, especially at high linear speeds and short dwell times, as are necessary for kinetic investigations. In the case of a liquid reaction, inert gas would have to be metered in with this type of reaction, which is an unnecessary effort in itself.

To avoid these problems, it has also often been proposed not to retain the catalyst in the reactor, but to carry it out with the product, and to separate it from the liquid phase using conventional separators, such as decanters, filters, filter candles, hydrocyclones or the like (e.g. US 3,901,660). Disadvantageously, the handling of moist solid or concentrated suspensions then becomes necessary when the solid is to be fed back into the reactor system as a catalyst. In addition, it is difficult to control the amount of catalyst to be recycled if the reaction is to be carried out continuously without fluctuating conversions in the reactor, since catalyst is continuously withdrawn from the reaction space.

Alternatively, the separation of catalyst and liquid outside the reactor via cross-flow filtration is proposed, in which part of the suspension is branched out of the reactor and recirculated by a microfilter operating at the same pressure and operated according to the cross-flow principle, and the liquid reaction product as Filtrate is withdrawn from the microfilter (DE 32 45 318). The disadvantage here is that a filter cake is also built up over time and has to be removed periodically, which leads to a shutdown the plant leads. In addition, it may be necessary to lower the temperature of the reaction mixture before entering the filter unit, since the known filter materials can only be operated at limited temperatures.

A disadvantage of all the external separation methods mentioned is that a solid suspension must be promoted. This requires additional pumps, the service life of which is also limited by solid abrasion.

When using whirlpool beds or slurry bubble columns, e.g. for the Fischer-Tropsch synihesis, the circulatory flow may possibly be generated by the freshly injected liquid or the rising bubbles. However, due to the often inadequate mass and heat exchange processes between the fluid phases and / or with the solid, problems can arise in the reaction control. It is therefore to be expected that lower conversions or, in the case of exothermic reactions, heat profiles in the reactor which are a hindrance to the reaction.

The object was therefore to find a process and a device in which the catalyst in its fully effective form can be used in the reaction area without the process having to be interrupted periodically for regeneration or purification. At the same time, the crude product of the reaction should continuously be obtained as a solid-free liquid.

It has now surprisingly been found that it is possible to continuously obtain a solids-free product stream from a reaction mixture in which a powdery catalyst is finely dispersed if the reaction is carried out in a reactor which has a filter element at the inlet and outlet and and drain can be interconnected so that the inlet can serve as an outlet and the outlet as an inlet. By switching the inlet and outlet, any deposits on the filter element are flushed back into the reaction space. The present invention therefore relates to a reactor for the continuous implementation of catalyzed liquid reactions in which the catalyst is dispersed in the reaction space, which is characterized in that it has at least one Inlet and an outlet, whereby all starting materials are supplied via an inlet and all products are discharged via an outlet, and the inlet and outlet are provided with a means which enables the inlet and outlet to be connected in such a way that an outlet previously serving as an outlet as an inlet serving as an inlet and at the same time an inlet serving as an inlet is used as an outlet, and at the inlet and outlet there is a filter element which retains the catalyst in the reactor, and a device is present in the reactor which distributes the catalyst homogeneously and ensures the starting materials in the reactor.

The present invention also relates to a process for the continuous implementation of catalyzed liquid reactions in at least one reactor in which the catalyst is dispersed in the reaction space, which is characterized in that the process is carried out in at least one reactor according to the invention.

The present invention also relates to an arrangement of at least two reactors according to the invention arranged in parallel and the use of the method according to the invention, a reactor according to the invention or an arrangement according to the invention for carrying out high-throughput screening. High-throughput screening in general and within the scope of the present invention includes the rapid testing of catalyst compositions and properties for their optimization with regard to their suitability for technical use for the reaction or reaction class under investigation, as well as the optimization of the reaction parameters required for this (e.g. pressure, temperature, volume flow) , hydrodynamic dwell time) in parallel operated, and preferably miniaturized and automated, devices understood.

The device according to the invention or the reactor according to the invention has the following significant advantages:

• An external separation of the catalyst is not necessary. This eliminates the problems that can arise when pumping suspensions, e.g. limited service life of pumps, deposits in pipes, etc.

• Elaborate process steps such as conveying a highly solid-laden liquid, cooling and releasing to filter-compatible pressures and feeding the Catalyst.

• The reactor according to the invention can in principle be implemented in any commercially available stirred tank reactor with at least one inlet and one outlet.

The product (filtrate) obtained from the device is generally free of solids, so that contamination of downstream process stages, e.g. in a distillation unit.

• The applicable pressures and temperatures are only limited by the approval of the boiler and the material properties of the filter elements used.

• The reactor according to the invention shows the same characteristics as a stirred tank reactor. • The reactor according to the invention can also be used in reactions in which the catalyst content is more than 20% by volume, preferably more than 30% by volume and particularly preferably more than 40% by volume.

The device according to the invention is also advantageous for the determination of the intrinsic reaction kinetics, because the use of finely dispersed catalyst granules is to be preferred, since the pressure drop compared to a fixed bed reactor can thereby be minimized with catalyst pellets. In addition, pore diffusion inhibition is largely avoided due to the small particle size, and in the case of exothermic reactions there are usually no local temperature peaks as in a fixed bed reactor, since the fluidized catalyst leads to isothermal reactor behavior through convective mixing. The reactor according to the invention makes it easy to carry out reactions with finely divided small catalyst particles, which is why such reactor / reaction combinations are particularly suitable for determining the intrinsic reaction kinetics, which is important for the scale-up of reactors.

The device according to the invention and the method according to the invention are described below, without the invention being restricted to these embodiments. The reactor according to the invention for continuously carrying out catalyzed liquid reactions in which the catalyst is dispersed in the reaction space is distinguished by the fact that the reactor has at least one inlet and at least one outlet, with all starting materials being fed in via one inlet and one outlet all products are removed. Inlets and outflows are provided with a means that enables Interconnect inlets and processes in such a way that an output previously used as an outlet is used as an inlet and at the same time an inlet serving as an inlet is used as an outlet. A filter element is present at each of the inlets and outlets, which retains the catalyst in the reactor. There is also a device in the reactor which ensures a homogeneous distribution of the catalyst and the starting materials in the reactor. Such a device can be, for example, a motor-driven stirrer, in particular an in-line stirrer.

The means for interconnecting the inlet and outlet can e.g. be a four-way valve, in which two outlets are connected to each other. If there is more than one outlet and one inlet, a valve with a correspondingly larger number of outlets must be used, or there is a four-way valve for each inlet and outlet. The valves used can be controlled manually or automatically (e.g. electrically or pneumatically), whereby the regulation can be carried out using a conventional process control system.

The means for interconnecting the inlet and outlet can be provided with a device which ensures periodic switching. However, it can be advantageous if the reactor is equipped with a pressure sensor which is connected to the process control technology which controls the agent as a function of the pressure in the reactor.

The filter elements present at the inlets and outlets in the reactor can be used as filter-active materials e.g. have a sintered metal frit, a ceramic frit, a ceramic composite, a monolithic ceramic, a polymer membrane, a metal wire fleece or knitted fabric or a wire mesh construction or consist entirely of these materials.

Depending on what reactions are to be carried out in the reactor, it may be advantageous or necessary if the reactor has a device for supplying or removing thermal energy. Such devices can be cooling or heating coils which are present in the interior of the reactor and / or in the wall thereof and through which a corresponding cooling or heating medium flows.

The filter elements can be hollow bodies of different geometries. These can be planar Slabs or columns with different base areas, such as a circle, ellipse, triangle, square, etc. The filter elements can be shaped like hollow rings or parts of hollow walls of a cylinder. At least two filter elements are present in the reactor according to the invention. The at least two filter elements are preferably of the same size or have at least an equal area of filter-active material, so that it is ensured that there is no unwanted pressure build-up due to different pressure when switching the inlet and outlet Flow cross sections come in and out. The filter-active materials can be present on the inside and / or the outside of the filter elements. The filter elements can be so large and shaped that they only form part of a cylinder shell when assembled, or so large that they form a complete cylinder shell composed of the filter elements. In the simplest case, a complete cylinder jacket is made up of two sections. For fluidic reasons, however, it may also be advantageous for the complete cylinder jacket to be composed of an even number, greater than two, sections, with a filter element serving as the inlet preferably being adjacent to two filter elements each serving as outlets. However, it can also be advantageous to arrange filter elements serving as inlet and outlet irregularly. The inlets and outlets to the filter elements can indeed be brought together and only fed to one means for switching. However, it has proven to be advantageous if, in the presence of several filter elements, one inlet is connected to only one outlet by means of a switchover device, in order to ensure that all inlets and outlets, and thus also the filter elements, have the same pressure (mass flow ) are flowed through. The means for switching can nevertheless be designed so that it can carry out several of the tightenings mentioned at the same time.

In a preferred embodiment, the reactor according to the invention has filter elements which are shaped like parts (hollow) walls of a cylinder (the permeate in these filter elements is removed from the interior of the hollow walls of the cylinder, while the retentate on the inner and / or outer sides of the Cylinder parts is retained). Furthermore, in this preferred embodiment, the reactor has at least one additional stirrer, which is at a distance of less than or equal to 1 cm on the inner and / or outer side (surface), preferably on the inner and outer side (surface) of the cylinder, preferably less than or equal to 2 mm, preferably Heiner equal to 1 mm on the surface of the

Filter elements, in particular the filter-active surfaces of the filter elements. The filter elements are preferably shaped like the half-shells (halves) of a cylinder and the agitator blades run past the inner and outer surfaces at a distance of less than or equal to 2 mm, preferably 1 mm, preferably 0.75 mm. The stirrer working on the outside

Past the surfaces of the filter elements is preferably an anchor stirrer. The stirrer, which runs past the inner surfaces of the filter elements, is preferably a blade stirrer with preferably two to ten blades. The passage of the stirrer at a predetermined distance from the filter-active surfaces of the filter elements prevents the build-up of a filter cake on the filter-active surface.

In a particularly preferred embodiment of the reactor according to the invention, the filter elements are also shaped like parts or half-shells (halves) of a cylinder, only the inside of the half-shells having the filter-active material and thus representing the filter-active surface. The special feature of this embodiment is that the filter elements are part of the cylindrical reactor wall or even form the entire reactor wall. Again, only two or even more, preferably an even number, of filter elements can be present, it being possible for the filter elements to be connected as inlets and outlets as described above. Again, a stirrer is preferably provided, which runs past the surface of the filter-active surface of the filter elements at a distance of less than or equal to 1 cm, preferably less than or equal to 2 mm, preferably less than or equal to 1 mm, on the surface of the filter elements. In this embodiment of the method according to the invention, the outlay on equipment is kept relatively low. This can happen in particular if only one stirrer is used, which is shaped in such a way that it runs past the surface of the filter-active surfaces of the filter elements at a predetermined distance and at the same time ensures sufficient mixing in the entire reactor.

It can be advantageous if the stirrer which is present for the homogeneous disperse distribution of the catalyst and the stirrer or stirrers which run past the inner and / or outer surfaces of the filter elements run on an axis. In this way, the outlay on equipment is kept as low as possible. However, in order to achieve an even better mixing, it can be advantageous if the stirrers are provided with means which enable opposing operation of the stirrer and / or operation of the stirrer at different speeds.

The reactors according to the invention can be reactors for production plants, technical equipment or small equipment. Accordingly, the size of the reactors according to the invention can vary in the range from 5 ml to more than 100 m ³ , the size of the reactor or the volume of the reactor being able to be adapted almost arbitrarily to the technically necessary conditions. If the reactors are reactors which are used on an industrial scale, for example for the oligomerization of olefins, in particular butenes, the reactors according to the invention have a size of from several liters to several hundred cubic meters, in particular from 0.1 m ³ to 200 m ³ , preferably from 1 to 100 m ³ and very particularly preferably from 5 to 50 m ³ . If the reactors according to the invention are, for example, laboratory reactors or reactors for high-throughput investigations, it can be advantageous if reactors have reaction vessels which have a reactor volume of 10 ml to 10,000 ml, preferably greater than 50 ml and very particularly preferably greater than 100 ml.

A method for continuously carrying out catalyzed liquid reactions in at least one reactor in which the catalyst is dispersed in the reaction space is accessible by means of the reactor according to the invention, which is characterized in that the method is carried out in at least one of the reactors according to the invention. As a process according to the invention, for example, oligomerization, metathesis, alkylation or isomerization reactions and heterogeneous bio-catalytic reactions can be carried out in this reactor. The reactor according to the invention is particularly preferably suitable for carrying out heterogeneously catalyzed high-pressure liquid reactions, such as, for example, the oligomerization of olefins, hydrogenation, metathesis, alkylation, isomerization and heterogeneously bio-catalyzed reactions. A particular advantage of using the reactor according to the invention lies in the fact that, in particular, processes can also be carried out in which the catalyst content in the reactor can be above 20% by volume, preferably from 30 to 50% by volume. An upper limit for the catalyst content is approximately 60 to 65% by volume, since the presence of a fluid medium can no longer be guaranteed if the catalyst content is even higher. Should with even higher catalyst proportions If there is still a fluid medium (a dispersion), the reactor according to the invention and thus also the method according to the invention can of course continue to be used.

The method according to the invention can preferably be carried out in such a way that the inflow and outflow to and from the reactor are automatically switched so that the inflow and outflow are interchanged when the pressure difference across the filter element increases so much that the flow rate set only increases due to an increase in pressure can be maintained in the reactor of more than 5%, preferably more than 1%, particularly preferably more than 0.5% compared to the initial pressure or to the pressure after the last switchover, or if a certain preset period of time has passed since the last switchover is. The time period is preferably selected so that it is less than or equal to the time that leads to a significant, measurable pressure increase. This time can e.g. B. can be determined in simple preliminary tests. The pressure increase in the reactor can e.g. be measured via a pressure sensor in the reactor. Switching can be done manually. The switchover is particularly preferably carried out by a process control system which automatically triggers the switchover at a corresponding pressure in the reactor or after a presettable period of time. To avoid technical effort, it is advantageous if the switchover is carried out periodically. Depending on the type and in particular size of the catalyst used and the pore size of the filter element used, the switchover must be carried out more or less frequently. Switching is preferably carried out every 10 minutes to every 24 hours, preferably every 0.5 hours to every 12 hours.

The method according to the invention can e.g. be the oligomerization of butenes in a temperature range from 50 to 10 ° C. and at pressures from 10 to 70 bar. If, for example, this is carried out at volume flows of 0.5 to 100 ml / min, when using a stainless steel mesh of 3.2 cm x 4.2 cm with a mesh size of 5 μm and when using a catalyst with a particle diameter of 15 μm, switching times have been achieved of approx. 30 min found as a particularly preferred switchover time.

The process according to the invention can also be carried out in such a way that the process is carried out in two or more reactors according to the invention operated in parallel and / or in series. In laboratory tests, the method is preferably in 2 to 50, preferably in 4 to 25 and very particularly preferably carried out in 9 to 16 reactors operated in parallel. Carrying out the process according to the invention in this way can be particularly advantageous if the miniaturized reactors according to the invention are used.

The reactors operated in parallel can be operated identically or differently in the process according to the invention. The reactors can all be charged with the same starting material mixture or the individual or grouped reactors of the reactors operated in parallel can be supplied with different starting material mixtures. The products obtained in the reactors can be worked up individually or analyzed. However, it is also possible to combine and analyze or process the products of all reactors or groups of reactors.

In addition to varying the composition of the starting materials, it can also be advantageous in the process according to the invention to set the same or different reaction conditions in individual or grouped reactors of the reactors operated in parallel, to which the same or different starting material compositions are fed. The reaction conditions, which can be varied, are preferably pressure, temperature and amount and / or type of the catalyst used.

To carry out the parallel reactions, the reactors according to the invention can preferably be arranged to arrangements according to the invention which have at least two reactors according to the invention arranged in parallel. The arrangement preferably has 2 to 50, preferably 4 to 25 and very particularly preferably 9 to 16 reactors arranged in parallel. The inlets and outlets to the reactors are preferably equipped with a switchover facility which makes it possible to interchange the inlets and outlets if the pressure rise in the reactor is more than 5% compared to the initial pressure or the pressure after the last switchover. The switchover of inflow and outflow can, however, take place automatically after a preset period of time has elapsed.

In the arrangement according to the invention, the same or different reactant mixtures can be fed to individual or grouped reactors of the reactors operated in parallel. This can be done, for example, via a distributor or dosing device. Also point out the reactors present in the arrangement according to the invention each have at least one means for setting reaction conditions. This can be, in particular, a heat exchanger which supplies the reaction mixture with heat or removes heat of reaction, so that, for example, isothermal or quasi-isothermal conditions can be set. Further means for setting the ReaMons conditions are, for example, pressure controls, inflow and / or outflow controls etc. Depending on the intended use, the reactors arranged in parallel in the arrangement according to the invention can be completely independent of one another, in particular with regard to the starting materials and product (sealed) or else the feed supply or Product removal can take place via a common inflow process. The individual reactors are preferably sealed against a transition of fluid connections from one reactor to the other, so that completely different reaction conditions can be set in the individual reactors.

By using several reactors according to the invention operated in parallel or an arrangement thereof according to the invention, the method according to the invention is suitable for being used for the rapid determination of optimal reaction parameters (high throughput screening). The possibility of miniaturization of the reactors according to the invention makes them particularly suitable for, in particular those with a volume of less than 100 ml

Use in high throughput screening.

The present invention is explained in more detail by way of example with reference to FIGS. 1 to 7, without being restricted thereto.

In Fig. 1, the operation of the liquid reaction apparatus according to the invention on a solid catalyst is exemplified. At least two filtration units (1 and 2) are located in a reaction chamber (3) which can be operated at the required reaction pressure and the required reaction temperature, preferably with the Hy (-xodynamics of a continuously operated stirred tank). These can be filter-active media, such as sintered metals , Ceramics, ceramic composites, monolith ceramics, polymer membranes, metal wire nonwovens or knitted fabrics or wire mesh constructions The first filter unit (1) supplies the liquid or a liquid saturated or enriched with gas as feed material (mixture) to the reactor (6) Filter unit (2) is the reacted liquid (product) withdrawn from the reactor (7). The pressure in the reactor can be maintained via an electromagnetically or pneumatically controlled pressure control valve (4) located behind the outlet frit. The filter elements are practically not exposed to a pressure gradient and are only subjected to minimal mechanical loads. Several stirrers (5a, 5b and 9) are provided for cleaning the filter elements and for mixing the reactor. Despite the filter elements being cleaned by the stirrers (5a and 5b), depth filtering can block the outlet filter elements. If an increase in pressure is observed, the flow in the filter elements is therefore reversed via a 4-way valve (8), so that supply is now carried out by filter (2) and discharge by filter (1).

2 shows a top view and a side view of the filter elements (1) and (2) which are fastened to one another by two brackets (10a and 10b) having a bore. Arrows represent the inflowing feed (6a) and the product stream (7a) carried away. A stirrer drive shaft (11) is shown in dashed lines, to which one or more stirrers can be attached. The shaft can be mounted in one or both bore holes (10a or 10b) for better guidance of the stirrers (12). This prevents possible imbalance in the stirrers, which can result in contact between the stirrers and filter units and thus possible damage to the filter units. Materials such as e.g. Bearing bronze or abrasion-resistant plastics are suitable.

In Fig. 3, an alternative construction of the reactor is shown schematically in a top view and a side view. The filter elements (lb and 2b) are in this case as an inlay on the inner wall of the reactor. In this construction, one half (half of the cylinder plus possibly half the bottom) of the inner wall of the reactor is the first filter element 1b and the other half is the second filter element 2b. The outer walls of the reactor are formed by the non-porous rear walls of the filter elements introduced as inlay, or The outer wall of the reactor forms the non-porous rear wall of the filter element. Inlet (6b) and outlet (7b) or first and second filter elements are separated from one another by impermeable barriers (13). The stirrer (5) in the middle serves to clean the filter surfaces and the mixing of the reactor and is driven by the shaft (11). This construction is particularly suitable to continuously conduct reactions in the dispersion perform the inventive method on a larger scale.

FIG. 4 shows an exemplary interconnection of a number n of reactors according to the invention with flow mixing, as shown in FIG. 1 or 3. The inflow into the reactors (21) is metered to the desired amount by regulator (22) and fed to the reactors. The fluids emerging from the reactor are fed to a selector (23) in which the reactor effluent is selected from one of the reactors and subjected to analysis (24), e.g. can be fed to a gas chromatograph or a mass spectrometer or other analysis devices. The remaining streams are disposed of (25) or other analyzers.

5 shows a diagram in which the graphically measured pressure is plotted against the test time. The experiment was carried out as in Example 2, with the difference that after 0.7 and 1 hour the flow direction was switched once. It can be clearly seen that after the reaction pressure has been set after approx. 0.05 hours, the pressure initially remains the same until the pressure rises steadily from approx. 0.3 hours, which can be attributed to blocking of the filter-active layer. By switching over and the associated flushing of the filter-active layer after about 0.7 hours, the reaction pressure can be brought back to the initial value. With a preventive switchover after one hour, the reaction pressure initially remains constant until the pressure rises again at around 1.45 hours. This experiment shows, on the one hand, that a blocking of the filter-active layer that has already taken place can be undone by a switchover, and, on the other hand, that blocking can be avoided by a timely preventive switchover.

FIGS. 6 and 7 graphically show the residence time curves for a test substance in the reactor according to the invention according to Example 2 and, in comparison, the residence time curves of the model of an ideal stirred tank reactor for two different inflow volume flows. The curves for a volume flow of 69 ml / min are shown in FIG. 6 and the curves for a volume flow of 28 ml / min are shown in FIG. 7. The experimentally determined and standardized values are shown as black squares. The calculated values are shown as a line. How to the graphics the courses of the experimental and calculated curves show no significant differences. It can therefore be assumed that the hydrodynamic behavior of the reaction vessel provided with the filter elements and stirrers corresponds approximately to that of an ideal stirred tank reactor.

The following examples are intended to illustrate the invention without restricting the scope which results from the description and the patent claims.

Embodiments for testing the flow behavior of the reactor according to the invention was in the following tests (example 1 and 2) a dispersion of 20 wt .-% silicate powder with a d ₅ o-value of 25 microns in hexane (n-hexane techn., Aldrich) , This was placed in the reactor. Then a certain stream of hexane at a pressure of 22 bar was passed through the inlet into the reactor and removed again via the outlet.

Embodiment 1

A filter combination as shown in FIG. 2, consisting of two filter units, which were installed in a 300 ml stirred tank reactor (Büchi), was used. The filter units have a filter-active area of 2.8 cm x 3.8 cm on the inside. The cross-section of inlet and outlet was 1/8 "each. The distance between the active filter surface and the rear wall of the filter element was also 1/8" in each case. The filter-active area consisted of a stainless steel mesh / stainless steel sieve with a 5 μm opening width. The filter elements were connected to each other by two stainless steel brackets, which have a hole for the stirrer shaft, with a distance of 3.4 cm between the inner surfaces. The stirrer shaft was guided centrally between the filter elements, so that the blade stirrer (5a) (5-blade stirrer, height = 3 cm, width of the individual blade = 1.7 cm, V4-A steel) attached to the porous inside of the cylindrical filter elements always sweeps at the same distance of 0.5 mm. An impeller stirrer with 4 stirring blades (angle to flow direction: 15 °) was attached to the lower end of the shaft, which ensures the largely homogeneous distribution of the disperse phase. The shaft rotated at a speed of 1000 rpm. With a filter area of 10.6 cm ² per filter unit, flow rates up to 50 ml / min (hexane) with a solid volume fraction of 20% by volume (silicate powder, ds ₀ = 15 μm) in continuous operation (> 1000 h). The changeover valve was triggered every 30 minutes in order to flush back blockages within the sieve pores. Without backwashing, the permeability of the filters decreased at operating times over 0.5 h under the conditions mentioned and the observed pressure in the reactor increased.

Embodiment 2

In a second exemplary embodiment, such filter elements were used to enlarge the filter area in which the outer side of the cylinder shell was also designed as a sieve. The filter elements are in turn soldered to one another via a stabilization rod. In order to avoid a filter cake build-up on the outer filter surface, an additional stirrer (for example an anchor stirrer (5b) was required, which deeply sweeps on the same shaft as the blade stirrer and sweeps over the outside of the filter elements at a distance of 0.5 mm. 4 cm ² per filter unit, flow rates up to 100 ml / min (hexane) with a solid volume fraction of 20% by volume (silicate powder, D ₅₀ = 15 μm) can be achieved in continuous operation (> 1000 h) min triggered in order to flush back blockages within the sieve pores Without backflushing the permeability of the filter drops during operating times of more than 0.5 h under the mentioned conditions, which is indicated by an increase in pressure in the reactor (see FIG. 5) in embodiment 1 near the bottom an impeller stirrer attached to the stirrer shaft, fo the suspended solid upward in the direction of the filter elements This results in an even distribution of solids in the entire reactor.

In both exemplary embodiments, no visible filter cake formation could be observed any more at stirrer spacings of <= 1 mm (observed in-situ by using a glass reactor). At high enough speed (depending on the flow rate), the reactor shows hydrodynamics that are comparable to that of an ideal stirred tank, despite the built-in components. This was shown by a comparison of the residence time curves of a test substance with those of the model of an ideal stirred tank reactor (FIGS. 6 and 7). As can be seen from the graphs in FIGS. 6 and 7, the two curves show no difference. Embodiment 3 The oligomerization of butenes (77.4% by weight of linear butenes and 22.6% by weight of fluid compounds which are inert under the reaction conditions) was carried out in a reactor as described in Example 1 with a built-in filter combination from Application Example 2 at 80 ° C. or 96 ° C and a pressure of 25 bar (the values obtained at 96 ° C are given in brackets below). The volume flow was approx. 5 nl / min. 25 g of a catalyst used for oligomerization as in DE 39 14 817 in Example 2 were used as the catalyst (average particle size d _P = 15 μm). A conversion to C ₈ to C ₂₀ oligomers of 25% (32%) was observed. The feed between the two filter elements was automatically switched every 30 minutes. The test ran for 2000 h without any noticeable blockage of the filter elements.

Claims

claims:

1. Reactor for the continuous implementation of catalyzed liquid reactions in which the catalyst is dispersed in the reaction space, characterized in that the reactor has at least one inlet and one outlet, all starting materials being supplied via the inlet and all products being removed via the outlet , and the inlet and outlet are provided with a means which enables the inlet and outlet to be interconnected in such a way that a previously serving outlet is used as an inlet and at the same time an inlet serving as an outlet is used as outlet, and to inlet and drain there is in each case a filter element which retains the catalyst in the reactor, and a device is present in the reactor which ensures a homogeneous distribution of the catalyst and the starting materials in the reactor.

2. Reactor according to claim 1, characterized in that the means for connecting the inlet and outlet is a four-way valve, in which two outlets are connected to one another.

3. Reactor according to claim 1 or 2, characterized in that the filter element as a filter-active material has a sintered metal frit, a ceramic frit, a ceramic composite, a monohthane structure, a polymer membrane, a metal wire fleece or a wire mesh construction.

4. Reactor according to one of claims 1 to 3, characterized in that the reactor has a device for supplying or removing thermal energy.

5. Reactor according to one of claims 1 to 4, characterized in that the reactor has a stirrer as a device for the homogeneous distribution of catalyst and starting materials.

6. Reactor according to one of claims 1 to 5, characterized in that the reactor has filter elements which are shaped like parts of a cylinder and has at least one additional stirrer which is in one piece on the inner and / or the outer surface of the cyclically shaped filter elements Distance of less than or equal to 1 cm.

Reactor according to claim 6, characterized in that the filter elements are shaped like the half-shells of a cylinder and the stirrer blades run past the inner and / or outer surfaces at a distance of less than or equal to 2 mm.

8. Reactor according to claim 5 or 6, characterized in that the filter elements are shaped like the half-shells of a cylinder, the inside of the half-shells represent the filter-active surface, the filter elements are parts of the reactor wall and at least one stirrer is present, which is on the surface of the filter-active area passes at a distance of less than or equal to 1 cm.

9. A process for the continuous implementation of catalyzed liquid reactions in at least one reactor in which the catalyst is dispersed in the reaction space, characterized in that the process is carried out in at least one reactor according to one of claims 1 to 8.

10. The method according to claim 9, characterized in that the process is an OH-polymerization, metathesis, alkylation or isomerization reaction or a heterogeneous bio-catalytic reaction.

11. The method according to claim 9 or 10, characterized in that the proportion of catalyst in the reactor is more than 20% by volume.

12. The method according to claim 9 to 11, characterized in that the inlet and outlet are switched so that the inlet and outlet are interchanged when the pressure increase in the reactor is more than 5% compared to the initial pressure or the pressure after the last switchover or that the switchover of inlet and outlet takes place automatically after a preset period of time has elapsed since the last switchover.

13. The method according to at least one of claims 9 to 12, characterized in that the method is carried out in two or more reactors operated in parallel according to one of claims 1 to 8.

14. The method according to claim 13, characterized in that the same or different reactant mixtures are supplied to individual or grouped reactors of the reactors operated in parallel.

15. The method according to claim 13 or 14, characterized in that the same or different reaction conditions are set in individual or grouped reactors of the reactors operated in parallel.

16. Arrangement with at least two reactors arranged in parallel, characterized in that that the reactors arranged in parallel are those according to one of claims 1 to 8.

17. The arrangement according to claim 16, characterized in that the inlets and outlets to the reactors are equipped with a UmschaltmögHchkeit, which makes it possible to interchange the inlets and outlets when the pressure increase in the reactor more than 5% compared to the initial pressure or pressure after the last switchover, or that the switchover of inlet and outlet takes place automatically after a preset period of time has elapsed.

18. Arrangement according to claim 16 or 17, characterized in that individual or combined reactors of the reactors operated in parallel can be supplied with different reactant mixtures.

19. Arrangement according to one of claims 16 to 18, characterized in that the reactors each have at least one means for setting reaction conditions.

20. The arrangement according to at least one of claims 16 to 19, characterized in that the individual reactors are sealed against a transition of fluid connections from one to the other reactor.

21. Use of a method according to one of claims 9 to 15, a reactor according to one of claims 1 to 8 or an arrangement according to one of claims 16 to 20 for carrying out a high-throughput screening.