DE102020124610A1 - MULTIPLE TUBE REACTORS - Google Patents

Abstract

The present invention relates to multi-tube reactors, multi-tube reactor stacks, overall reactors, and their application and use.

Description

All documents cited in the present application are fully incorporated by reference into the present disclosure (=incorporated by reference in their entirety).

The present invention relates to multi-tube reactors, for example as cooled honeycomb flow reactors, methods for converting substances using these reactors, and the use of the reactors, in particular in each case with regard to the hydrogenation of carbon oxides

Radial flow reactors are technically established and used in a variety of exothermic reactions. These reactors filled with a catalyst bed are usually operated adiabatically, i.e. temperature gradients develop which are disadvantageous for the reaction process. The catalyst pellets are placed in nets and are flown through radially. The gas stream can be directed several times over the catalyst bed, depending on the design of the flow path over the length of the reactor. In the prior art, catalyst pellets are often used as a bed, which have a lower thermal conductivity compared to honeycomb bodies. The educt gas throughput that can be achieved in this way is often unsatisfactory or insufficient. In addition, in the designs of the prior art, the catalyst beds are often not cooled or the heat of reaction is not efficiently dissipated directly from the bed.

For example off DE 10 2012 220 926 A1 , WO 2009/147203 A1 , WO 2010/034564 A1 , WO 2017/180957 A1 radial flow reactors are known which have an annular catalyst bed through which the reactants flow radially. For example from the DE 10 2016 125 641 A1 tube bundle reactors are known in which several tube reactors are (co-)axially aligned and the reactants flow through them. However, one problem with these known reactors is that they cannot easily be scaled up to commercially relevant sizes. The previous embodiments of honeycomb reactors as tube bundle reactors are not economical since the required short tube length results in an unfavorable length-to-diameter ratio and the heat dissipation on the outside of the reactor tubes is not optimal.

In this respect, based on the current state of the art, there is still considerable potential for improvement.

Accordingly, it was an object of the present invention to provide reactors which no longer have the disadvantages of the prior art, or at least only have them to a significantly reduced extent. The reactors should be easy to manufacture, easy to maintain and very effective, especially for reactions that require, particularly large, heat input or removal.

Other objects will become apparent to those skilled in the art upon review of the claims and the following description.

These and other objects, which become apparent to the person skilled in the art from the present description, are achieved by the subject matter presented in the claims, the dependent claims representing preferred and particularly advantageous embodiments.

In the context of the present invention, unless otherwise stated, all quantitative data are to be understood as weight data.
In the context of the present invention, the term “ambient temperature” means a temperature of 20°C. Unless otherwise stated, temperatures are in degrees Celsius (°C).
Unless otherwise stated, the reactions and process steps listed are carried out at ambient pressure (=normal pressure/atmospheric pressure), ie at 1013 mbar.
Pressure specifications in the context of the present invention, unless otherwise specified, mean absolute pressure specifications, ie X bar means x bar absolute (bar _a ) and not x bar gauge.

In the case of relative information such as above, below or the like, an observer standing upright on the ground is assumed as the reference system within the scope of the present invention.

The present invention is directed to multi-tube reactors, multi-tube reactor stacks and total reactors, as well as methods and uses as described in the independent claims. The subordinate claims describe particularly advantageous and preferred embodiments of the present invention. The following description shows specific embodiments of the description or invention in order to further illustrate the context of the present invention.

The present invention relates to multi-tubular reactors having an outer shell and, concentrically thereto, an inner shell of reduced size, thereby forming a gap-shaped cavity between the shells and surrounding the inner shell. Between the inner and the outer shell are at least two connecting the coats and the coats pierced reaction tubes at the points of contact whereby the space inside the inner shell is fluidly connected to the space outside the outer shell.

In embodiments of the present invention, the multi-tube reactors consist of the device parts mentioned.

In other embodiments of the present invention, the multi-tube reactors comprise the apparatus parts mentioned and possibly other attachments or internals.

In embodiments of the present invention, the multi-tube reactors are annular in structure.

In embodiments, the multi-tubular reactors comprise an outer cylindrical shell and, arranged concentrically thereto, an inner cylindrical shell with a smaller diameter, whereby an annular gap-shaped cavity is formed between the shells and surrounding the inner shell. Furthermore, between these jackets there are at least two reaction tubes which are radially arranged starting from the geometric center of the cylinders, connect the jackets and pierce the jackets at the points of contact, whereby the space inside the inner jacket is fluidically connected to the space outside the outer jacket.

In embodiments of the present invention, the ring-shaped multi-tube reactors consist of the device parts mentioned.

In the basic configuration of the multi-tube reactor, the circumferential gap-like or annular gap-like cavity is open at the top and bottom. Depending on the application, the peripheral gap-shaped or annular cavity can optionally be covered from above and below, but then preferably in a fluid-tight manner with a cover with a fluid inflow device and a cover with a fluid outflow device. These covers may be permanently attached, e.g. welded, or they may be removable and attached only via screws, flanges or the like.

In the context of the present invention, the number of reaction tubes per multiple tube reactor is not limited from the outset. The specialist will plan the number of tubes accordingly, based on the respective planned form of application and the planned sales volume.
In embodiments of the present invention, the multi-tube reactors have from 2 to 100 reaction tubes, preferably from 3 to 60 reaction tubes, particularly preferably from 5 to 40 reaction tubes.
In the context of the present invention, the tube diameters of the reaction tubes are also not limited per se from the outset.
These can also be adjusted accordingly, based on the precisely planned application and the desired throughput, in particular with regard to the planned reaction and the way in which it is or must be carried out.
In embodiments of the present invention, the reaction tubes have a tube diameter of 10 to 200 mm, preferably 20 to 150 mm, particularly preferably 35 to 110 mm.
The same applies to the tube length of the reactor tubes in the present invention.
In embodiments of the present invention, the reactor tubes have a length of 50 to 500 mm, preferably 100 to 400 mm, particularly preferably 200 to 300 mm.

In principle, the various dimensions of the reactor tubes of the present invention can be combined with one another in different ways, depending on the application. In variants of the present invention, 5 to 40 reaction tubes are arranged per multiple tube reactor, the tube diameter of which is between 35 and 110 mm and the length of which is between 200 and 300 mm.

In the context of the present invention, the reaction tubes do not necessarily have to be round. The reaction tubes of the multi-tube reactors of the present invention can also be oval or n-sided, but in preferred embodiments they are round. The circular embodiment has several advantages, including ease of manufacture and better resistance to elevated pressures.

Although the reaction tubes are primarily intended within the scope of the present invention to be the place where the planned chemical reaction takes place (reaction space), they also serve to connect and stabilize the two jackets to one another or to one another.

In addition, it is possible in embodiments of the present invention to connect the two jackets to one another by means of further installations or attachments. For example, it is possible in embodiments of the present invention to cover the cavity formed by the two jackets from both sides with a wire mesh or a similar structure. In this way, the multi-tube reactor of the present invention is given additional stabilization without, however, significantly impeding the accessibility of the cavity, so that, for example, a fluid can flow unhindered can flow through the cavity formed. Alternatively, the lids mentioned above can also increase stability.

In a simple variant of the present invention, the multi-tube reactor can be described as a disc around which the surrounding fluid, in particular air, flows freely and can flow freely through the cavity.

The multi-tube reactors of the present invention do not have to be circular, they can also be oval or n-sided. However, as already described above for the reaction tubes, the round embodiment is preferred.

In this case, “round” means in particular circular, with the deviation from the ideal circular shape preferably being less than 10%, preferably less than 5%, particularly preferably less than 2% and most preferably less than 1%.

In the context of the present invention, the term "concentric" in relation to the inner and outer shell means that the deviations from the ideal geometric concentricity are at most 20%, preferably at most 15%, more preferably at most 10%, particularly preferably at most 5% and more preferably at most 2%. It is clear to the person skilled in the art that with these values - as with the other production-related tolerances for in principle all the device components described in the present invention - certain production-related deviations can occur, since production can be carried out completely without deviations from the ideal dimensions or ideal parameters technically either cannot be reached at all or is disproportionately expensive.

The precise geometry of the gap-shaped cavity formed by the two jackets in the multi-tube reactors according to the invention is dependent on the geometry of the jackets.
Although it is preferred within the scope of the present invention that the geometry of the inner cladding be the same geometry as that of the outer cladding, except for dimensions, this is not essential.
For example, in embodiments of the present invention, it is possible to design the inner shell in the shape of a rectangle and the outer shell in the shape of an oval (when viewed in plan).

However, it is just as possible to design the outer shell as a rectangle and the inner shell as an oval.
On the other hand, it is preferred if both the inner and the outer shell have the same geometry, ie both are designed either rectangular or oval.
Preferred variants of the present invention are characterized in that both the inner shell and the outer shell are designed as an oval, particularly preferably as a circle.

In some embodiments, the multi-tube reactors described according to the present invention have an inlet for reactants on one side of the reaction tubes and an outlet for products on the respective other side of the reaction tubes. This embodiment is used in particular when individual multi-tube reactors are used as described above.

In embodiments of the present invention, internals are arranged in the reaction tubes. These internals can be honeycomb bodies, for example, in particular those made of metal or metal alloys. It can also be preferred that these internals are coated with catalytic material.
In some embodiments of the present invention, it is therefore preferred if metallic honeycomb bodies coated with catalytic material are arranged in the reaction tubes.
In other embodiments of the present invention, it is preferred if metallic honeycomb bodies are arranged in the reaction tubes. In this case, the metallic honeycomb bodies themselves can act as catalysts or, in other variants, be additionally coated.

In variants of the present invention, solid catalyst carriers can be arranged in the reaction tubes, as in FIG DE 10 2106 125 641 A1 are described, are used.

In variants of the present invention, the solid catalyst supports arranged in the reaction tubes of the present invention can therefore have two, preferably a large number of, channels with structured inner surfaces. At least two channels are preferred. The use of more than 200 channels is particularly preferred in these variants. The inner surfaces can be made of metal. Metals or alloys which have good thermal conductivity, for example steel and/or aluminum, are preferably suitable for this purpose. Graphites and/or carbides, which can also be used in combination with the aforementioned metals, are also conceivable. The multiplicity of preferably more than 200 channels takes up the gas flow. Catalysts can be arranged on the inner surfaces of these individual channels, provided that the materials of the Channel surfaces are not themselves catalytically active. These variants are channels with a diameter of preferably 0.3 mm to 3 mm, particularly preferably 1 mm to 2 mm, in particular 1.5 mm.

In variants of the present invention, the inner wall thickness of the channels can be between 10 μm and 10 mm, preferably 10 μm to 2 mm and particularly preferably 50 to 120 μm.

In variants of the present invention, solid catalyst carriers with a multiplicity of channels in a honeycomb configuration are therefore used. In variants, metallic solid catalyst carriers come into consideration, in particular catalyst carriers such as can also be used in exhaust gas aftertreatment systems of motor vehicles with internal combustion engines. These are bodies that, together with the walls, form a large number of channels through which a fluid can flow.

In variants of the present invention, the solid catalyst carriers are structures which, in an alternative, are designed in such a way that they can be joined together with their smooth and straight transverse surfaces with those of the other channels of the solid catalyst carrier in order to create a connection. However, this is not absolutely necessary. The outer surfaces of the channels can be connected using all methods familiar to a person skilled in the art. That is, clamping methods, gluing methods or welding methods can be considered. Because the channels are preferably metal or contain metal, welding is a preferred form of connection. However, it is not absolutely necessary that the walls of the channels fit together exactly. It is essential that the channels can be flowed through and are stable at a pressure of up to 100 bar. This is particularly important for the weld seams. The channels themselves are exposed to almost no differential pressure.
In variants of the present invention, the channel density is 50-600 cpsi (channels per square inch), preferably 100 to 400 cpsi, particularly preferably 150 to 300 cpsi, particularly preferably 200 cpsi.
In variants, the void fraction of the solid catalyst support can correspond to the fraction that is filled with the gas mixture to be reacted, for example synthesis gas, and is preferably 40 to 85%, particularly preferably 65%. The thermal conductivity of the solid catalyst support can also be adjusted by varying the empty spaces, the inner and outer wall thickness of the channels, the material of the solid catalyst support and/or its channel densities. Furthermore, the absorption and/or dissipation of the heat can also be influenced by means of the material or the filling of the inner walls of the channels of the solid catalyst support.

The solid catalyst supports arranged in the reaction tubes can have two, preferably a large number of, channels with structured inner surfaces. At least two channels are preferred. The use of more than 200 channels is particularly preferred in these variants. The inner surfaces can be made of metal. Metals or alloys that have good thermal conductivity, e.g. steels and/or aluminum, are preferably suitable for this purpose. Also conceivable are graphites and/or carbides, which can also be used in combination with the aforementioned metals. The multiplicity of preferably more than 200 channels takes up the gas flow. Catalysts can be arranged on the inner surfaces of these individual channels if the materials of the channel surfaces are not themselves catalytically active. These variants are channels with a diameter of preferably 0.3 mm to 3 mm, particularly preferably 1 mm to 2 mm, in particular 1.5 mm.

In embodiments of the present invention, the channel lengths of the honeycomb bodies can be 50 to 300 mm, preferably 75 to 250 mm and particularly preferably 100 to 200 mm.

It goes without saying that the characteristic data and parameters mentioned in each case can be combined as desired depending on the application and can be selected accordingly by the person skilled in the art.

In particularly preferred embodiments of the present invention, the multi-tubular reactors of the present invention are a particular form of radial flow honeycomb reactors. In this case, honeycomb bodies are preferably arranged in the reaction tubes as described above.

In these embodiments of the present invention, reactants are fed radially outward from the inner side of the reaction tubes, undergoing a chemical reaction in the reaction tubes and exiting as products on the outer side. It is of course clear to the person skilled in the art that, depending on the reaction taking place in the reaction tubes, the term “products” can also represent a mixture of unreacted reactants and reacted reactants, ie products, and possibly by-products and by-products.

Another subject of the present invention are multi-tube reactor stack with at least two stacked multi-tube reactors as described above. The multi-tube reactor stacks of the present invention can comprise or consist of at least two of the multi-tube reactors described.

The individual multi-tube reactors are connected to one another in such a way that the respective jackets are arranged one above the other in a fluid-tight manner and form a common inner jacket and a common outer jacket. As a result, they also form a common space within the common inner shell and a common gap-shaped cavity between the common inner shell and the common outer shell.

The multi-tube reactor stacks of the present invention can thus be understood as an increase in multi-tube reactors. In principle, only elevated coats and corresponding spaces would be formed.

Within the scope of the present invention, however, a distinction is made between the multi-tube reactors and the multi-tube reactor stacks, since the multi-tube reactors can have different heights and therefore may also include several levels of reaction tubes, but have a limited height in order to maintain a certain character of modularity. In contrast, the multi-tube reactor stacks of the present invention are formed in a modular manner from a plurality of multi-tube reactors according to the invention by stacking them one on top of the other.

This gives a very high degree of flexibility when constructing an (overall) reactor for a desired reaction. Within the scope of the present invention, this concept makes it possible to adapt the reactors to increasing or decreasing requirements with relatively little effort by expanding or reducing the multi-tube reactor stack by one or more multi-tube reactors.

In preferred embodiments of the present invention, several identically configured multi-tube reactors are arranged one above the other for the multi-tube reactor stack. This means that in particular the geometric shapes and dimensions of the multi-tube reactors are identical.

Although the present invention is not limited to a specific number of multi-tube reactors in the multi-tube reactor stacks, the exact number of multi-tube reactors in the multi-tube reactor stacks depends on the amounts to be reacted. This is known to the person skilled in the art and the person skilled in the art will avoid arranging an unnecessarily large number of multi-tube reactors one above the other in order not to make the overall device unnecessarily expensive and too large.

In embodiments of the present invention, 2 to 50 multiple tube reactors are arranged one above the other for the multiple tube reactor stack, preferably 2 to 40, particularly preferably 2 to 30 and in particular 2 to 20.

In embodiments of the present invention, the respective multi-tube reactors are connected to each other in the manufacture of the multi-tube reactor stacks in such a way that they are not movable.
In embodiments, this can be done by screwing or gluing, or by a connection via flanges, for example.
The connection via flanges is preferred because of its flexibility and effectiveness in embodiments of the present invention.

In this context, it is preferred for these embodiments if the individual multiple reactors are already equipped with appropriate flanges, so that the multiple tube reactor stacks can be produced and connected to one another quickly and easily. Thus, preferred embodiments of the present invention are also multi-tubular reactors which a priori have means for connection to other multi-tubular reactors according to the present invention.

It is possible in variants of the present invention in the manufacture of the multi-tube reactor stack to arrange seals between the individual multi-reactors. In other variants of the present invention, the individual multi-reactors can be welded or glued to one another when the multi-tube reactor stack is manufactured.

In any case, it is essential in the multi-tube reactor stacks according to the invention that the multi-tube reactors are or are connected to one another in a fluid-tight manner, so that no fluid can flow between the individual multi-tube reactors.

Similar to what has already been described above for the multi-tube reactors, the reaction tubes in the multi-tube reactor stacks can each have an inlet for reactants on one side and an outlet for products on the other side.

In preferred embodiments of the present invention, it is possible to enclose multiple tube reactors or multiple tube reactor stacks within an outer reactor shell. In these embodiments, the multi-tube reactor of the present invention or the multi-tube reactor stack of the present invention are arranged in the reactor housing such that a cavity is formed between the outer walls and the reactor shell. The cavities formed between the inner and outer walls of the multi-tube reactor or multi-tube reactor stack are connected to the surrounding reactor housing in such a way that a fluidic connection between the interior of the gap-shaped cavity and the space between the outer walls of the multi-tube reactor or multi-tube reactor stack and the reactor housing is not possible is. Likewise, in these embodiments, no fluidic connection is possible between the space within the inner shell of the multi-tube reactor or multi-tube reactor stack and the cavity formed between the inner and outer shells of the multi-tube reactor or multi-tube reactor stack. The gap-shaped cavity between the inner and outer walls of the multi-tube reactor or multi-tube reactor stack is connected to the reactor housing in such a way that fluid can be fed into the gap-shaped cavity from outside the surrounding reactor housing and, on the other hand, fluids can also be discharged from the cavity to the outside of the surrounding reactor housing can.

The surrounding reactor housing also has a fluid inlet, through which a fluid, in particular a fluid containing reactants, can be conducted into the space within the inner shell of the multi-tube reactor or the multi-tube reactor stack. This fluid is then passed through the reaction tubes to the outer space outside the outer shell of the multi-tube reactor or multi-tube reactor stack. The surrounding reactor shell is also designed in such a way that it has at least one outlet for the fluids that reach the outer space, ie in particular the reaction products.

A further subject of the present invention is therefore also an overall reactor which comprises at least one multi-tube reactor as described above or at least one multi-tube reactor stack as described above.
This overall reactor is configured for flow through the reaction tubes of the multi-tube reactors or the multi-tube reactor stack, so that a reaction medium is conducted through the reaction tubes from the inside to the outside.
For this purpose, this overall reactor comprises a fluid-tight outer casing around the at least one multi-tube reactor or the at least one multi-tube reactor stack.
The outer casing of the overall reactor is spaced apart from the outer jacket of the at least one multi-tube reactor or of the at least one multi-tube reactor stack and forms an outer cavity around it. The outer shell of the overall reactor also has at least one inlet, preferably for reaction medium, into the space within the inner shell.
In embodiments of the present invention it is preferred if this supply is located at the top, in particular centrally above the space within the inner shell.
Furthermore, the outer casing has at least one outlet, preferably for reaction product, ie reacted reaction medium, from the space outside the outer shell of the at least one multi-tube reactor or of the at least one multi-tube reactor stack.
This discharge is preferably arranged below.
The outer shell also has at least one supply for fluids into the cavity formed between the shells of the multi-tube reactors or the multi-tube reactor stack, preferably configured for a heat exchange medium. This feed is preferably located below the cavity formed between the shells.
Furthermore, the outer shell of the overall reactor has at least one outlet for fluids from the cavity formed between the jackets, preferably configured for a heat exchange medium. This outlet is preferably arranged above the cavity formed between the jackets.

In embodiments of the present invention, it is possible to arrange the entire reactor not only in an upright position, but also in a horizontal position, for example if the space available on site requires this (upright here means orthogonal to the earth's surface). For fluidic and practical reasons, however, it is usually preferred to arrange the entire reactor in an upright position.

In embodiments of the present invention, the overall reactor has a plurality of inlets and/or a plurality of outlets for the fluid flowing through the gap-shaped cavity formed between the jackets. In preferred embodiments of the present invention, the fluid flows upwards through the gap-shaped cavity formed between the jackets from below against the force of gravity.

In preferred embodiments of the present invention, the medium or fluid conducted into the space within the inner jacket flows downwards from above with the force of gravity.

Within the scope of the present invention, in principle all commonly used heat carriers can be used as the heat exchanger medium flowing through the hollow space formed between the jackets. Heat exchange media selected from the group consisting of water, aqueous solutions, dibenzyltoluene, oil, for example silicone oils, steam, molten salts and molten metals are preferably used, preferably selected from the group consisting of water, oil, steam and molten salts, particularly preferably oil.

The height of the overall reactor is not fixed in principle within the scope of the present invention, but results from the on-site conditions. In particular, the quantities to be converted must be taken into account. On the other hand, of course, the height is also limited by the statics and the load-bearing capacity of the floor.

In embodiments of the present invention, the height of the entire reactor is 0.5 m to 10 m, preferably 0.5 m to 7 m, more preferably 0.5 m to 5 m, in particular 0.6 m to 3.50 m.

Furthermore, the subject matter of the present invention is an overall reactor as just described, in which an installation for guiding the flow is arranged in the space inside the inner shell. The supplied reaction fluid is guided through this installation in such a way that the flow is as favorable as possible. In preferred configurations, this installation for flow guidance is a pyramidal or conical workpiece, for example a baffle plate, the base of which is arranged on the bottom of the inner casing of the outer jacket of the overall reactor, hence preferably opposite the supply of the reaction medium.

In embodiments of the present invention, the materials used for the multi-tube reactors, the multi-tube reactor stacks or the overall reactor are conventional materials known from the prior art which are suitable for the respective fields of application. These are known to the person skilled in the art and are selected depending on the intended use. In addition to the planned reaction pressure that the materials have to withstand in the planned shape, the materials must also be resistant to the reactants, the reaction medium, the products, by-products, the heat transfer medium and, if appropriate, the environment.

In preferred embodiments of the present invention, particularly suitable materials for the reactors are steel, high-grade steel, steel alloys such as, for example, those with the material number 1.4541.

The various reactors of the present invention are suitable for a wide variety of reactions, the specific suitability in each case being limited only by a suitable selection of materials for the reaction to be carried out.

Due to the specific structure of the respective reactors of the present invention, the reactants are conducted in the form of a radial flow through the reaction tubes mentioned. Because a gap-shaped cavity is formed by the respective inner and outer jackets, through which the reaction tubes pass, a very effective heat supply or removal is possible by means of a thermally conductive fluid flowing through this cavity.

The present invention therefore also includes methods for carrying out chemical reactions in which the reactants are introduced into the reaction tubes on the one hand and are subjected to a reaction in the reaction spaces, ie the reaction tubes, and the products or product mixtures on the other side of the reaction tubes be taken away. It is also part of this process that the reaction spaces, i.e. the reaction tubes, are simultaneously flushed with a thermally conductive medium and, in this respect, are cooled or heated.

In particular, the present invention also relates to a process for catalytic hydrogenation comprising passing reactants through at least one reaction space in the form of a reaction tube with simultaneous cooling of the at least one reaction space, the reaction being carried out in a multi-tube reactor, a multi-tube reactor stack or an overall reactor as described above .

The reactors of the present invention are very well suited for the catalytic conversion of gas mixtures.

• Als Gasgemische kommen in dieser Ausgestaltungsform Kohlenstoffmonoxid und/oder Kohlenstoffdioxid enthaltende Gemische in Betracht, welche auch höhere Kohlenwasserstoffe mit zwei oder mehr als zwei C-Atomen enthalten können. In bevorzugten Varianten sind dies Synthesegase, insbesondere eine Mischung aus CO/CO₂/H₂/CH₄/H₂O. Für die CO₂-Methanisierung werden CO₂ und H₂ eingesetzt. Für die Kohlenstoffmonoxidmethanisierung werden vorzugsweise CO/H₂/CO₂/CH₄ verwendet. Für die Methanolsynthese kommen CO/H₂/CO₂/CH₄ in Betracht. Hierbei sind für die Reaktionen nicht alle Bestandteile zwingend erforderlich. Auf der anderen Seite können noch weitere Bestandteile durchaus hinzukommen. Diese können Verunreinigungen von Stickoxiden, Aminen, Ammoniak und organischen Verbindungen mit Heteroatomen (H, O, P, Cl, F) enthalten.
• Für die Synthese von Methan werden Verhältnisse von H₂/CO = 3:1 und H₂/CO₂ = 4:1 angestrebt; das CO/CO₂-Verhältnis ist für die Synthese von untergeordneter Bedeutung (jedoch nicht zu vernachlässigen, da hier die Verkokung des Katalysators verhindert wird), solange ausreichend H₂ für die jeweilige Kohlenstoffoxid-Komponente verfügbar ist. Denn die Umsetzung hängt vorrangig vom Gehalt an H₂ ab. Eine Wasserdampfzugabe von 15-30% ist bei der Methanisierung von CO vorteilhaft. Sofern eine Methanisierung von CO₂ (ohne Anwesenheit von CO) angestrebt wird, ist die Zugabe von Wasserdampf nicht erforderlich.
• Die Temperaturen liegen bevorzugt zwischen 150 und 650 °C, bevorzugt zwischen 200 und 600 °C, besonders bevorzugt 220 und 550 °C. Die Temperatur des Temperiermittels liegt vorzugsweise bei 180 bis 400 °C, mehr bevorzugt bei 200 bis 300 °C.
• In Varianten können Katalysatoren auf Nickel-Basis zum Einsatz kommen. Darin sind vorzugsweise 65 - 75 Gew.-% NiO und ein Rest Al₂O₃ als Bindemittel enthalten. Der Druck liegt vorzugsweise zwischen 5 und 20 bar.
• Für die Synthese von Methanol ist der Zusatz von Wasserdampf nicht erforderlich. Das Verhältnis von CO:CO₂ beträgt vorzugsweise 5:1. Der Anteil an H₂ liegt vorzugsweise bei 50-70%. Die Temperatur beträgt vorzugsweise 200-600 °C, besonders bevorzugt 220-550 °C. Als Katalysatoren werden bevorzugt Cu-ZnO-Al₂O₃-Systeme verwendet. Der Druck liegt vorzugsweise bei 10 bis 30 bar, kann aber in varianten auch bei bis zu 100 bar liegen.
• Bei einem Temperaturbereich von 200-220 °C ist die Reaktionsgeschwindigkeit so gering, dass hohe modifizierte Verweilzeiten notwendig sind, um einen hohen Umsatz zu erzielen, d.h. die eingesetzte Katalysatormasse bezogen auf den umsetzbaren Eduktgasstrom aus CO und/oder CO₂ erreicht Werte von größer als 200 kg*s/mol. Dies ist realisierbar über große Mengen Katalysator >250 g/m² und/oder lange Kanäle des Festkörperkatalysatorträgers.

One embodiment of the present invention relates to the following:

• In this embodiment, suitable gas mixtures are mixtures containing carbon monoxide and/or carbon dioxide, which can also contain higher hydrocarbons having two or more than two carbon atoms. In preferred variants, these are synthesis gases, in particular one Mixture of CO/CO ₂ /H ₂ /CH ₄ /H ₂ O. CO ₂ and H ₂ are used for the CO ₂ methanation. CO/H ₂ /CO ₂ /CH ₄ are preferably used for the carbon monoxide methanation. CO/H ₂ /CO ₂ /CH ₄ can be used for the methanol synthesis. In this case, not all components are absolutely necessary for the reactions. On the other hand, other components can certainly be added. These can contain impurities from nitrogen oxides, amines, ammonia and organic compounds with heteroatoms (H, O, P, Cl, F).
• Ratios of H ₂ /CO = 3:1 and H ₂ /CO ₂ = 4:1 are aimed at for the synthesis of methane; the CO/CO ₂ ratio is of secondary importance for the synthesis (however, it should not be neglected, since coking of the catalyst is prevented here), as long as sufficient H ₂ is available for the respective carbon oxide component. Because the implementation depends primarily on the H ₂ content. A water vapor addition of 15-30% is advantageous in the methanation of CO. If a methanation of CO ₂ (without the presence of CO) is desired, the addition of steam is not necessary.
• The temperatures are preferably between 150 and 650.degree. C., preferably between 200 and 600.degree. C., particularly preferably 220 and 550.degree. The temperature of the tempering medium is preferably 180 to 400°C, more preferably 200 to 300°C.
• In variants, catalysts based on nickel can be used. It preferably contains 65-75% by weight of NiO and a remainder of Al ₂ O ₃ as a binder. The pressure is preferably between 5 and 20 bar.
• The addition of steam is not necessary for the synthesis of methanol. The ratio of CO:CO ₂ is preferably 5:1. The proportion of H ₂ is preferably 50-70%. The temperature is preferably 200-600°C, more preferably 220-550°C. Cu-ZnO-Al ₂ O ₃ systems are preferably used as catalysts. The pressure is preferably from 10 to 30 bar, but can also be up to 100 bar in variants.
• In a temperature range of 200-220° C., the reaction rate is so low that high modified residence times are necessary in order to achieve a high conversion, ie the catalyst mass used, based on the reactable reactant gas stream of CO and/or CO ₂ , achieves values greater than 200 kg*s/mol. This can be achieved using large amounts of catalyst >250 g/m ² and/or long channels in the solid catalyst support.

• - als Eduktgase werden CO und CO₂ eingesetzt,
• - Druck in den Reaktionsrohren 5 bis 150 bar, bevorzugt 6 bis 30 bar, insbesondere 16 bar,
• - Geschwindigkeit des Gaseingangsstroms von 0,01 bis 1 m/s, bevorzugt 0,05 bis 0,5 m/s,
• - Temperatur des Gasgemisches von 180 bis 350 °C, bevorzugt 200 bis 300 °C,
• - Temperatur in den Wabenkörpern von 200 bis 600 °C, bevorzugt 220 bis 550 °C,
• - Temperatur des Wärmeträgermediums von 180 bis 350 °C, bevorzugt 200 bis 300 °C.

The reactors of the present invention are particularly well suited for methanation reactions, especially when the following parameters are observed:

• - CO and CO ₂ are used as educt gases,
• - Pressure in the reaction tubes 5 to 150 bar, preferably 6 to 30 bar, in particular 16 bar,
• - velocity of the gas inlet stream from 0.01 to 1 m/s, preferably 0.05 to 0.5 m/s,
• - temperature of the gas mixture from 180 to 350 °C, preferably 200 to 300 °C,
• - Temperature in the honeycomb bodies from 200 to 600 ° C, preferably 220 to 550 ° C,
• - Temperature of the heat transfer medium from 180 to 350 °C, preferably 200 to 300 °C.

With the reactors according to the invention, conversions of 80 to 100% can be achieved.

The present invention also relates to the use of the multi-tube reactors described, the multi-tube reactor stacks described or the overall reactors for catalytic chemical reactions, preferably hydrogenation reactions, and in particular the hydrogenation of carbon oxides.

In the present invention, the reactor tubes are arranged in a star shape in the radial direction and not as parallel tubes as in a conventional tube bundle reactor.
In preferred embodiments, a coolant flows around the radially arranged tubes.
In further preferred embodiments, the interior of the radially arranged tubes is filled with honeycomb bodies, which can in particular be catalytically coated honeycomb bodies.

As already mentioned, the dimensions of the reactors according to the invention are not particularly restricted and are determined as a function of the production output required in each case. In the case of commercial use, efforts are made, for economic reasons, to dimension the reactors as large as possible. In a first step, the radial and axial dimensions of the reactor chamber can be determined based on the reaction technology requirements. The external reactor dimensions then result from the space required by the corresponding apparatus parts for conducting the reaction gases and the heat transfer medium and from design requirements.

In one embodiment of the present invention, the reactor is accessible for maintenance and repair work. Depending on the size of the In the reactor, this can take place, for example, via one or more manholes, which, in variants, can be arranged in an upper and/or lower hood of the reactor, if present. Other access options are the feed line for the reaction gas(es), the outlet line for the product gas or via flaps provided for this purpose. For example, a detachable connection, eg a flange, can be provided in the supply or discharge line in order to release the line for entry or intervention.

During operation of the reactor, different thermal expansions of the reactor shell and other reactor elements can occur. In order to avoid impermissible tensions between the various groups of apparatus, conventional compensators can be attached or installed. These are an example of measures that are customary in the trade, such as screws, couplings, valves, which do not necessarily have to be named, but should be read by the specialist.

The arrangement of the individual reaction tubes within the scope of the present invention enables simple scalability, particularly in the case of the radial arrangement of the individual reaction tubes. Because the individual multi-tube reactors can be stacked modularly depending on the reactor output. In the multi-tubular reactors of the present invention, a homogeneous temperature profile is achieved, leading to more defined conditions in the reaction zone, and hence better yields and selectivities; thus as a result to an intensification of the process. The investment costs for the pressure vessel are reduced because the length-to-diameter ratio increases and the wall thicknesses required for the vessel are therefore lower.

The scaling up of the reactors or the conversion which can be carried out is no longer a problem thanks to the reactor design of the present invention, in particular in the embodiments as radial flow honeycomb reactors.

The reactors of the present invention can be used excellently in power-to-gas systems for coupling electricity and the gas network.

With the devices of the present invention, higher educt gas throughputs per reaction tube can be achieved than was the case in the prior art. In embodiments of the present invention, the heat dissipation is significantly improved, in particular when using metallic honeycomb bodies, which has a positive effect on conversions, selectivities and yields due to the more homogeneous temperature distribution.

• - 5 bis 40 Reaktionsrohre,
• - Durchmesser der Reaktionsrohre von 35 bis 110 mm,
• - Länge der Reaktionsrohre von 200 bis 300 mm.

In a variant of the present invention, it is particularly preferred if the multiple tubular reactors of the present invention have the following characteristics:

• - 5 to 40 reaction tubes,
• - diameter of the reaction tubes from 35 to 110 mm,
• - Length of the reaction tubes from 200 to 300 mm.

• - Dichte der Kanäle in den Wabenkörpern von 200 cpsi,
• - Kanäle mit einem Durchmesser von 1,5 mm,
• - Kanallängen der Wabenkörper von 100 bis 200 mm,
• - Innenwandstärken der Kanäle von 50 bis 120 µm.

In one variant of the present invention, it is particularly preferred if honeycomb bodies are used as solid catalyst carriers in the reaction tubes of the multi-tube reactors according to the present invention, which have the following characteristics:

• - density of the channels in the honeycombs of 200 cpsi,
• - channels with a diameter of 1.5 mm,
• - channel lengths of the honeycomb bodies from 100 to 200 mm,
• - Inner wall thickness of the channels from 50 to 120 µm.

In a variant of the present invention it is particularly preferred if the multi-tube reactor stacks comprise 1 to 20 multi-tube reactors.

• - einen Mehrfachrohrreaktorstapel 1 bis 20 Mehrfachrohreaktoren umfasst,
• - wobei diese Mehrfachrohreaktoren 5 bis 40 Reaktionsrohre mit einem Durchmesser von 35 bis 110 mm und einer Länge von 200 bis 300 mm umfassen, und
• - in den Reaktionsrohren als Festkörperkatalysatorträger Wabenkörper mit einer Dichte der Kanäle von 200 cpsi, einem Durchmesser der Kanäle von 1,5 mm Kanallängen von 100 bis 200 mm und Innenwandstärken von 50 bis 120 µm angeordnet werden.

In one variant of the present invention, it is particularly preferred if the entire reactor

• - a multi-tube reactor stack comprising 1 to 20 multi-tube reactors,
• - these multiple tube reactors comprising 5 to 40 reaction tubes with a diameter of 35 to 110 mm and a length of 200 to 300 mm, and
• - Be arranged in the reaction tubes as a solid catalyst carrier honeycomb body with a density of the channels of 200 cpsi, a diameter of the channels of 1.5 mm, channel lengths of 100 to 200 mm and inner wall thicknesses of 50 to 120 microns.

In one variant of the present invention, it is particularly preferred if the overall reactor is equipped with a multiple tube reactor stack of 1 to 20 multiple tube reactors, these multiple tube reactors comprising 5 to 40 reaction tubes with a diameter of 35 to 110 mm and a length of 200 to 300 mm, and in the reaction tubes with honeycomb bodies as solid catalyst supports a channel density of 200 cpsi, a channel diameter of 1.5 mm, channel lengths of 100 to 200 mm and inner wall thicknesses of 50 to 120 µm, is used for a methanation reaction in which CO and CO ₂ are used as educt gases, the pressure in the reaction tubes is from 5 to 150 bar, preferably from 6 to 30 bar, in particular 16 bar, the velocity of the gas inlet stream is from 0.01 to 1 m/s, preferably from 0.05 to 0.5 m/s , the temperature of the gas mixture is from 180 to 350 °C, preferably 200 to 300 °C, the temperature in the honeycomb bodies is from 200 to 600 °C, preferably 220 to 550 °C, and the temperature of the heat transfer medium is from 180 to 350 °C, preferably 200 to 300 °C.

The reactors according to the invention can be used in variants of the present invention for exothermic catalytic or endothermic catalytic reactions. Furthermore, they can be used for oxidation, hydrogenation, dehydrogenation, nitration, alkylation reactions, for the production of hydrocarbons from alcohols or dimethyl ether, for the synthesis of gasoline from methanol and the synthesis of methanol from synthesis gas.

The person skilled in the art can easily carry out the precise design of the reactor, such as size, wall thicknesses, materials, etc., for the reaction conditions envisaged for a specific reaction within the framework of his general specialist knowledge.

If, in the description of the system according to the invention, parts or the entire system are marked as “consisting of”, this means that this refers to the essential components mentioned. Natural or inherent parts such as lines, valves, screws, housings, measuring devices, storage tanks for educts/products, etc. are not excluded. However, other essential components, such as other reactors or the like, which would change the course of the process, are preferably excluded.

The various embodiments of the present invention, e.g. - but not exclusively - those of the various dependent claims can be combined with one another in any way, provided that such combinations do not contradict one another.

• 1 beschreibt das aus dem Stand der Technik bekannte Prinzip eines Radialflussreaktors. Hierzu wird von oben Reaktionsmedium, beispielsweise Gas, in einen Zentralraum in den Reaktor eingeleitet. Ausgehend von diesem zentralen Raum strömt dann das Reaktionsmedium nach außen durch eine kreisförmig um den Zentralraum angeordnete Katalysatorschüttung, wobei die Reaktion in dieser Katalysatorschüttung abläuft. Das Produkt bzw. Produktgemisch tritt dann in einen äußeren Raum ein, der innerhalb der Gesamtreaktorhülle liegt, jedoch außerhalb der ringförmigen Katalysatorschüttung. Auf einer der Zuführungsseite gegenüberliegenden Reaktorseite wird dann das Produkt bzw. das Produktgemisch durch einen oder mehrere Auslässe aus dem Reaktor abgeführt. Solche Reaktoren sind üblicherweise konzentrisch rund aufgebaut.
• 2 zeigt schematisch einen Mehrfachrohrreaktor 1 gemäß vorliegender Erfindung. 2a) zeigt eine schräge Draufsicht auf einen Mehrfachrohrreaktor 1 gemäß vorliegender Erfindung. Dabei ist zu sehen, dass der innere und der äußere Mantel 2, 3 konzentrisch umeinander angeordnet sind und in diesem Fall beide eine Kreisform aufweisen. Weiterhin ist zu sehen, dass die inneren und äußeren Mäntel 2, 3 durch die Reaktionsrohre 4 miteinander verbunden sind, wobei die einzelnen Reaktionsrohre 4 die jeweiligen Mäntel an ihren Berührungspunkten 5 durchstoßen. Angedeutet durch den Bereich 4a ist eine optional in den Reaktionsrohren 4 befindliche Katalysatorschüttung.
• 2b) stellt eine Draufsicht des gleichen Mehrfachrohrreaktors 1 dar. Hierbei ist noch besser zu sehen, dass die inneren und äußeren Mäntel 2, 3 zusammen eine konzentrische, runde Konfiguration aufweisen, wobei die einzelnen Reaktionsrohre 4, welche die beiden Mäntel 2, 3 miteinander verbinden und an ihren Berührungspunkten 5 durchstoßen, radial konzentrisch angeordnet sind, ausgehend von dem geometrischen Mittelpunkt der beiden Mäntel 2, 3 als Bezugspunkt.
• 3 zeigt einen Gesamtreaktor 9 gemäß vorliegender Erfindung in einem seitlichen Aufschnitt.

The present invention is explained in more detail below with reference to the drawings. The drawings are not to be interpreted as limiting and are not true to scale. The drawings are schematic and furthermore do not contain all the features that conventional devices have, but are reduced to the features essential for the present invention and its understanding, for example screws, connections etc. are not shown or not shown in detail. The same reference symbols indicate the same features in the figures, the description and the claims.

• 1 describes the principle of a radial flow reactor known from the prior art. For this purpose, reaction medium, for example gas, is introduced into a central space in the reactor from above. Starting from this central space, the reaction medium then flows outwards through a catalyst bed arranged in a circle around the central space, with the reaction taking place in this catalyst bed. The product or product mixture then enters an outer space which lies within the overall reactor shell but outside the annular catalyst bed. The product or the product mixture is then discharged from the reactor through one or more outlets on a reactor side opposite the feed side. Such reactors are usually built concentrically round.
• 2 Figure 1 shows schematically a multi-tube reactor 1 according to the present invention. 2a) 1 shows an oblique plan view of a multi-tube reactor 1 according to the present invention. It can be seen here that the inner and outer shells 2, 3 are arranged concentrically around one another and in this case both have a circular shape. It can also be seen that the inner and outer shells 2, 3 are connected to one another by the reaction tubes 4, with the individual reaction tubes 4 piercing through the respective shells at their points of contact 5. A catalyst bed optionally located in the reaction tubes 4 is indicated by the region 4a.
• 2 B) 1 shows a top view of the same multi-tube reactor 1. It can be seen even better that the inner and outer shells 2, 3 together have a concentric, round configuration, with the individual reaction tubes 4 connecting the two shells 2, 3 to one another and to pierce their points of contact 5, are arranged radially concentrically, starting from the geometric center of the two shells 2, 3 as a reference point.
• 3 shows an overall reactor 9 according to the present invention in a lateral section.

In the representation, this overall reactor 9 comprises a multiple-tube reactor stack 6 consisting of seven multiple-tube reactors 1 arranged one above the other, arranged in an overall reactor 9. A cylindrical installation 8 for flow guidance is shown in the inner space 10. The seven multi-tube reactors 1 of the present invention, which have been assembled into the multi-tube reactor stack 6, are connected to one another via flanges 7 in this illustration. It can also be seen here that this multi-tube reactor stack 6 is connected to the outer casing 17 of the overall reactor 9 via connection attachments 16 correspondingly adapted in terms of their size and is also connected to these connection attachment elements 16 via flange connections 7 . The reaction gas is introduced here from above through the gas inlet 12 into the inner space 10 and the product is removed again from the overall reactor 9 via the gas outlet 13 shown at the bottom left. Also illustrated here as an example are two feed devices 14 for heat exchange medium on the lower side of the overall reactor 9 and on the upper side of the overall reactor 9 two removal devices 15 for heat exchange medium.

Reference List

1

multi-tube reactor

2

inner coat

3

outer coat

4

reaction tube

4a

catalyst bed

5

Point of contact/penetration of the reaction tube through the jacket

6

Multi-tube reactor stack (of seven multi-tube reactors)

7

Flanges/flange connections

8th

cylindrical installation (for flow control)

9

overall reactor

10

internal space (between the inner walls of the multi-tube reactors)

11

outer space

12

gas entry

13

gas leak

14

Supply for heat exchange medium

15

Discharge for heat exchanger medium

16

connecting attachments

17

outer reactor envelope

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• DE 102012220926 A1 [0004]
• WO 2009/147203 A1 [0004]
• WO 2010/034564 A1 [0004]
• WO 2017/180957 A1 [0004]
• DE 102016125641 A1 [0004]
• DE 102106125641 A1 [0032]

Claims (10)

comprising multiple tube reactor - an outer shell and concentrically arranged an inner shell of smaller size, whereby between the shells a gap-shaped cavity is formed around the inner shell, and - between the jackets at least two reaction tubes connecting the jackets and penetrating the jackets at the points of contact, whereby the space inside the inner jacket is fluidically connected to the space outside the outer jacket. multiple tube reactor claim 1 comprising - an outer cylindrical jacket and an inner cylindrical jacket with a smaller diameter arranged concentrically thereto, whereby an annular cavity in the form of an annular gap is formed between the jackets and running around the inner jacket, and - between these jackets at least two radially arranged starting from the geometric center of the cylinders, reaction tubes connecting the shells and piercing the shells at the points of contact, whereby the space inside the inner shell is fluidly connected to the space outside the outer shell. Multi-tube reactor according to claim 1 or 2 , characterized in that the reaction tubes have an inlet for reactants on one side and an outlet for products on the other side. Multi-tube reactor according to any one of Claims 1 until 3 , characterized in that internals are arranged in the reaction tubes, preferably honeycomb bodies, particularly preferably metallic honeycomb bodies, in particular honeycomb bodies coated with catalytic material. Multi-tube reactor stack comprising at least two stacked multi-tube reactors according to one of Claims 1 until 4 , wherein the individual multi-tube reactors are connected to one another in such a way that the respective shells are arranged one above the other in a fluid-tight manner and have a common inner shell, a common outer shell, a common space within the common inner shell and a common cavity between the common inner shell and the common outer shape coat. Overall reactor comprising at least one multi-tube reactor according to one of Claims 1 until 4 or at least one multi-tube reactor stack according to claim 5 configured for the reaction medium to flow through the reaction tubes from the inside to the outside, characterized in that - a fluid-tight outer shell is arranged around the at least one multi-tube reactor or the at least one multi-tube reactor stack, the outer shell being surrounded by the outer shell of the at least one multi-tube reactor or the at least one spaced from the multi-tubular reactor stack and forming a cavity therearound, - the outer shell has at least one inlet, preferably for reaction medium, into the space inside the inner shell, - the outer shell has at least one outlet, preferably for reacted reaction medium, from the space outside the outer shell has, - the outer shell has at least one inlet into the cavity formed between the shells, preferably for a heat exchange medium, - the outer shell has at least one outlet from the cavity formed between the shells, preferably for a heat Ausher medium exhibits. Total reactor according to claim 6 , characterized in that in the space within the inner shell an installation for flow guidance is arranged, preferably a pyramidal or conical baffle plate whose base surface is arranged on the side facing away from the reaction medium supply. Process for catalytic hydrogenation comprising - passing reaction medium through at least one reaction space in the form of a reaction tube, - with simultaneous cooling of the at least one reaction space, characterized in that the reaction in a multi-tube reactor according to one of Claims 1 until 4 , according to a multi-tube reactor stack claim 5 or according to an overall reactor claim 6 is carried out. Use of the multi-tube reactor according to any one of Claims 1 until 4 , according to the multi-tube reactor stack claim 5 or according to the overall reactor claim 6 for gas phase reactions. use after claim 8 for exothermic catalytic or endothermic catalytic reactions or for oxidation, hydrogenation, dehydrogenation, nitration, alkylation reactions, for the production of hydrocarbons from alcohols or dimethyl ether, for gasoline synthesis from methanol, methanol synthesis from synthesis gas, preferably hydrogenation reactions, particularly preferred the hydrogenation of carbon oxides, in particular the methanation of carbon oxides.

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