WO2011095566A1 - Reactor device and method for optimizing the measurement of the temperature curve in reactor pipes - Google Patents

Abstract

The invention relates to a reactor device comprising normal pipes and thermal pipes provided with a temperature probe, each type of pipe being filled with catalyst bodies. In order to be able to model the temperature profile that develops in the normal pipes in the thermal pipes, each type of pipe is filled with such catalyst bodies that the ratio of the catalytic activity to the pipe wall surface in a segment of the pipes determined by a reaction section is the same in normal pipes and thermal pipes.

Description

Reactor device and method for optimizing the measurement of the temperature profile in reactor tubes

The invention relates to a reactor apparatus having at least a first group G _m of pipes comprising at least one normal pipe filled with catalyst bodies K _m and a second group G _n of pipes comprising at least one thermo pipe provided with a temperature measuring apparatus comprising second catalyst bodies K _{n is} filled, wherein the catalyst body K _m , _n each in an in

Longitudinal direction of the tubes along a reaction path S extending volume portion are arranged. Further

The invention relates to a method for providing such a reactor device and a method for

Preparation of at least one product using the reactor apparatus.

Exothermic reactions, such as the partial oxidation of hydrocarbons, in which only short contact times between a reactant and a solid catalyst can be realized, are usually in industrial scale in

Tube bundle reactors carried out. A shell-and-tube reactor comprises a plurality of reaction tubes arranged in one

Reactor housings are arranged, which of a

 Heat transfer medium is flowed through. The heat transfer medium flows around the pipes, so that a rapid heat exchange between pipes and heat transfer medium is achieved. In the tubes a solid catalyst is arranged, the bed of which

gaseous educt is flowed through. Since the gas stream is divided into many individual gas streams, each one flow through a single tube, in a reaction in the tube reactor is generally achieved a well reproducible result, since the flow distribution over the

Entity of the reaction tubes away only very small

Deviations result. Furthermore, a very rapid approximation of the temperature in the individual reactor tubes is possible by the heat transfer medium, so that the reaction can be performed for example in a very narrow temperature range, even if it has a strong exothermic heat of reaction. However, the problem is the control of such

 Reactor, as generally not in each individual tube of the reactor individually a temperature profile can be determined. For example, when starting the reactor, so if a

Catalyst, which still contains organic binder, burned out and thus activated, it is essential that a certain temperature is not exceeded, so that, for example, sintering operations of the catalyst are largely suppressed. By sintering operations, the

Properties of the catalyst can be permanently changed and especially in a local overheating, the catalytic activity of the catalysts can weaken greatly. Such processes are generally not reversible. Thus, if the catalyst overheats during activation, this can have a major impact on the routine operation of the reactor, since then the yield of the reactor significantly

reduced.

On the one hand to achieve a high yield and order

On the other hand, to avoid total oxidation of the starting materials and to suppress the formation of by-products, the reaction usually has to be within a very narrow range

 Temperature range are performed. Furthermore, the age is aging

Catalyst over its lifetime, so that the

Reaction conditions must be readjusted by For example, the reaction temperature or the concentration of a promoter in the gas stream is increased to a

Compensate for loss of activity of the catalyst.

It is therefore desirable in itself for the most accurate control of the reactor, the temperature or the

Temperature profile within the individual reaction tubes to measure as accurately as possible. In the practical

The procedure is carried out in such a way that in a reactor which, for example, 20,000 normal tubes comprises, so

Reaction tubes, in which no temperature measurement is made, about 5 to 10 thermotubes are provided, which should allow a representative temperature measurement in the reactor. A thermal tube is a reaction tube which is provided with a device for measuring the temperature. These thermo tubes should reflect the temperature profile of all normal pipes as representative as possible. But this is difficult.

In order to measure the temperature in one of the tubes, a protective tube is usually arranged along the longitudinal axis in the interior of the thermal tube, in which in turn a

Temperature sensor is arranged, for example a

Resistance thermometer.

For various reasons, however, it is not possible in practice to map the temperature profile in the normal tube exactly in the thermal tube.

A technical difficulty already exists in the fact that the reactors can never be built exactly, but always

Tolerances in the dimensions and arrangement of different reactor components occur. Thus, the protective tube would have to be arranged exactly centric in the thermal tube over its entire length. Any already minimal deviation from the centric-axial position in the direction of the pipe wall leads due to the radial temperature gradient between tube axis and cooled tube wall to significant deviations in the measured

Temperature. The deviations can be up to several 10 ° C. A thermocouple in a protective tube, which at some locations within the reaction tube of this

deviates centric-axial position, thus generating a non-representative temperature profile, the actual

Temperature history does not reflect.

The catalyst bodies are arranged in the annular gap between the protective tube and the inner surface of the thermal tube. It is usually not possible to arrange the catalyst bodies in the thermal tubes and in the normal tubes in the same way. in the

Generally, the catalyst bodies in the thermal tubes and the normal tubes have a different bulk density. Also, the flow conditions of the reaction gas in the normal pipe and thermo pipe due to the installation of the

Protective tube and different from the normal tube usually differently selected tube cross-section. This different catalyst arrangement and the

Different flow conditions cause the heat and thus the temperature profile in

Flow direction for normal pipe and thermal pipe

are different.

The temperatures measured in the thermo tubes can therefore not be directly transferred to the normal tubes, but must first be corrected. This can

for example, done in such a way that the arrangement of the catalyst body in the thermal tube is modified so that the temperature profile is adapted to the temperature profile in the normal tube.

US 2008 / 0014,127 A1 describes a test method with which the reaction conditions for a catalytic gas phase reaction in a shell-and-tube reactor are determined can. The test conditions are determined on a significantly smaller number of tubes, as in the tube bundle reactor intended for industrial production

are included. In the simplest case, a test reactor is used, which comprises two tubes which are in their

 Dimensions correspond to the tubes, as provided in the technical reactor. The first pipe will be with

Filled catalyst bodies. The second tube is also filled with catalyst bodies, but additionally contains one

Temperature measuring device with which the temperature profile in the tube can be determined. The test reactor is then adjusted to a certain temperature by the two tubes are lapped with a heat transfer medium having a certain temperature. It is then determined the temperature profile in the second tube and the composition of the reaction products in the first tube. The temperature is then changed until the best conditions for the reaction

were found. The conditions for the technical reactor are then determined on the basis of the test reactor

Parameter set so that the temperature in the

 Thermal tube of the reactor results in a product composition in the normal tubes, as they were determined with the test reactor.

In this method, therefore, the conditions for the technical reactor using a test reactor are determined. A monitoring of the start-up phase or an adjustment of the

Reaction condition to the aging of the catalyst is not possible.

In EP 1 484 299 certain tubes of a

Tube bundle reactor selected for the measurement of the temperature profile. In this case, a tube bundle reactor is used, which is provided with baffles for the heat transfer medium. The temperature profile is measured only in such pipes, which are not connected to a baffle plate. Also in this proposed solution, a different bed of catalyst body in normal pipes and thermal tubes is not considered.

In EP 0 873 783 Al is proposed as a solution

different amounts of active material in normal pipe and

Thermo tube to use, so the different

To balance conditions in the two tubes. On the one hand, the mean linear velocity of the gas flow in all tubes is set to the same value. For this purpose, the pressure loss is measured by passing an amount of an inert gas through the tube in question, the amount of gas being chosen to be proportional to the free cross-sectional area of the tube. On the other hand, the amount of FestStoffteilchen which is filled in the normal pipe and in the thermal tube, chosen so that the ratio of mass of the solid particles to the free cross-sectional area for normal pipe and thermal tube is the same. For those described in EP 0 873 783 AI

Reactor device so the condition applies

A ^R A ^T

Wobei bedeutet:

Where:

A ^R : the amount of active mass in the standard tube

A ^T : the amount of active mass in the thermal tube

r _a ^R : the inner radius of the normal pipe

r _a ^T : the inner radius of the thermal tube

n ^T : the outer diameter of the arranged in the thermal tube

 Thermowell for the temperature sensor.

The adjustment of the pressure loss and thus the linear

Gas velocity over the catalyst particles can be increased by the use of solid particles of different size and / or Geometry done. For this purpose, for example, in the thermal tube, a mixture of solid catalyst bodies and from the

Full catalysts produced split can be used. For this purpose, according to a certain formula, a share of

Grind unsupported catalysts into a fine split and fill the mixture of split and full catalysts into the thermal tube.

Although the method allows an approximation of

Temperature profile of thermal tube and normal tube. The

However, the procedure is up for an application

 Shell catalysts not possible because the catalyst can not be ground to split without his

To lose efficiency. In one application of

On full catalysts, the mixture of full catalyst and fine split produced from the full catalyst can not necessarily be filled homogeneously over the entire tube length into the thermal tube. When filling the two

Fractions in the thermal tube separate them at least partially. Also during the operation of the

Tube bundle reactor is carried out a further separation, since the finer parts migrate into the lower part of the thermal tube. Thus, the pressure drop over the length of the

Thermotube not constant. The reaction conditions in

Normal tube and thermal tube are therefore not the same, so that the temperature profile in the thermal tube the temperature profile in

 Normal pipe reproduces only inaccurate. The patent describes the application of the method to solid catalysts. These can be easily ground to a split. The possibility of applying the method to coated catalysts is mentioned in the description. However, it is not explained how such an adjustment of normal pipe and thermal tube in the case of coated catalysts is to be made because

Shell catalysts in grinding their catalytic

Lose efficiency. The invention therefore an object of the invention to provide a reactor device available, in which the thermal tubes reproduce the temperature profile in the normal tube as accurately as possible. This object is achieved with a reactor device with the

Characteristics of claim 1 solved. advantageous

Embodiments of the reactor device are the subject of the dependent claims.

In the systematically carried out by the inventors

Tests have shown that the temperature profile in the normal pipe can be much better represented by the temperature profile in the thermal tube when the activity of the arranged in a certain volume of the pipe section active mass to the inner surface of the tube is set in this section and this ratio for both the normal pipe also set approximately the same for the thermal tube.

In order to map the temperature profile of the normal tube in the thermal tube, according to one embodiment, the modified residence time T _m0 d of the reaction _gas in the

Normal tubes and the thermo tubes set to a substantially same value. The modified residence time T _m0 d of the reaction _gas is defined here as the quotient of mass of active mass in the reactor and the residence time τ of the reaction gas under standard conditions (DIN 1343, 0 ° C, 1013 mbar). The residence time τ is again defined here as the quotient of reactor volume and volume flow of

Reaction gas at standard conditions. The volume flow is defined as the volume of gas, for example given in Nm ³ , which flows in a unit time, for example one hour, through the reactor, for example a pipe or a boiler.

As in this embodiment, not the linear

Gas velocity is used as a parameter, but the modified based on the amount of active material

Residence time i _mod , the same conversion is achieved with the same chemical composition of the active composition in normal pipes and thermal pipes, if 1) according to the invention the ratio

Active mass per tube wall surface and 2.) the residence times in both tubes are identical.

For example, the linear gas velocity as an adjustment parameter would not account for a different bulk density in the two types of tubes. In the

The reactor device according to the invention thus moves a partial volume of the gas stream with approximately the same

Speed in both tubes parallel from the inlet side to the outlet side, whereby in normal tubes and thermal tubes an equal conversion is achieved. In the implementation in a real technical reactor, however, can be ideal

Conditions are usually not realized, so that deviations from the ideal state are observed.

An "essentially equal value" is therefore to be understood as meaning that the parameters pressure drop, quotient

Active mass and pipe wall surface and / or modified

_Dwell time T _m0 d may show a deviation, which is caused by technical tolerances, both in the tubes within a group and between tubes of different groups. Under a substantially same value is therefore a

State understood in which the parameters pressure drop, quotient of active mass and tube wall surface and modified residence time ^~ u _m0 d of the reaction _gas in an individual tube not more than ± 20%, according to an embodiment not more than ± 10%, according to another embodiment no longer than ± 7% of the mean (arithmetic mean), which is determined over the total volume of the tubes.

According to one embodiment, the ratio of the

Pressure drop, measured on the standard pipe, to the pressure drop, measured at the thermal tube, values between 0.8 and 1.2, according to another embodiment, values between 0.9 and 1.1.

The back pressure on a standard pipe or a thermal pipe, measured at a gas flow of 4 Nm ³ / h, according to one embodiment in the range of 1 to 5 bar _absolute , according to another embodiment in the range of 1.1 to 1.6 bar _absolute .

The pressure drop across a standard pipe or a thermal pipe, measured at a gas flow of 4 Nm ³ / h, according to one embodiment is in the range of 80 to 600 mbar, according to another embodiment in the range of 90 to 500 mbar.

According to one embodiment, the ratio of the

modified residence time i _mod, measured in the normal tube, the modified residence time i _mod, measured in the thermometer tube, values from 0.7 to 1.4, according to a further embodiment, values between 0.8 and 1.2, and according to still another

Embodiment values between 0.9 and 1.1.

The space-time velocity (GHSV) in the normal tubes and the thermal tubes is in one embodiment in the range of 500 to 10,000 h ^-1 , according to another embodiment in the range of 800 to 4,000 h ^_1 . In the technical implementation can usually not in all tubes of the reactor, the same GHSV set but it must be accepted deviations. According to one embodiment, the GHSV of a particular tube does not deviate by more than ± 20%, according to another embodiment by not more than ± 10%, and according to another embodiment by not more than ± 5% of the mean of the GHSV (arithmetic mean) across all the tubes of the reactor, off.

The pressure drop and the modified residence time ^~ u _m0d are, unlike _those defined in the theory of the reaction _technique , preferably measured before the reactor goes into operation. This will be an inert gas stream is passed through the individual tube and with this inert gas the pressure drop and the

modified residence time ^~ u _m0d determined and adjusted if necessary. The determination is carried out preferably at room temperature, for example in a range of 10 to 40 ° C, in particular at a temperature of 20 ° C. Nitrogen gas or, for example, also compressed air can be used as the inert gas.

The reactor device initially corresponds to a conventional tube bundle reactor. The tube bundle reactor comprises in

Essentially two groups of pipes. As normal pipes such pipes are called, which with catalyst bodies

are loaded, but no device for measuring the

Have temperature. The normal pipes form the group G _m of pipes. Thermo tubes are tubes which are charged with catalyst bodies and comprise a measuring device with which the temperature or the temperature profile within the tube can be measured. The thermo tubes form the group G _n of tubes. A common tube bundle reactor comprises about 5,000 to 30,000 normal tubes and 3 to 20

Thermal tubes. Higher or lower numbers, however, are

also possible. The tubes are arranged in a boiler, which is flowed through by a heat transfer medium,

for example, a molten salt. The tubes are preferably arranged evenly distributed inside the vessel, wherein the distance of the longitudinal axes between adjacent tubes preferably in the range of 20 to 80 mm, according to a

Embodiment selected in the range of 35 to 45 mm. Deviations from these ranges are possible. The

Heat transfer medium flows around the pipes arranged in the boiler so that heat can be supplied to the pipes or heat can be removed from the pipes. The tubes are preferably arranged parallel to one another and usually have a length between 1 m and 8 m, usually 2 to 5 m, for example 3 to 3.5 m up. Deviating dimensions from these areas are possible. In the tubes is one of the

Catalyst _bodies K _mjn formed catalyst _bed arranged. The catalyst bed is preferably arranged in a region of the tube which passes through a heat transfer medium

can be thermostated. In the longitudinal direction of the tubes, the catalyst bed preferably extends over at least 50%, according to another embodiment over at least 70% and according to another embodiment over at least 80% of the length of the tubes. Usually, the entire length of the tube is not occupied by the catalyst bed, for example, space for mechanical catalyst support, bodies for adjusting the pressure drop or for preheating the reaction gas to

To have available. According to one embodiment, the catalyst bed occupies less than 97% of the length of the tube, according to another embodiment, less than 90% of the length of the tube. In the heat transfer medium

Trapped space of the reactor can baffles

be provided, which divert the heat transfer medium and mix it, whereby a better and uniform heat transfer to the pipes or from the pipes is achieved away, so that the reaction in all tubes under approximately the same conditions, especially at a same

Temperature takes place. The tubes can open at their two ends in each case in a common gas space, so that the educts from the common gas space flows into the individual, catalyst-charged tubes and flow on the other side of the tube, the reaction products in a common gas space, from which then the Distribution to processing equipment, such as distillation columns or

Wash towers, can be done.

The tubes are made of a material which is stable under the reaction conditions and in particular does not embrittle during operation of the reactor. A suitable one Material for the production of the tubes is, for example, ferritic steel. The tubes have according to a

Embodiment an inner diameter of 15 to 50 mm and an outer diameter in the range of 16 to 55 mm. However, dimensions deviating from these ranges are possible. Normal pipes and thermo tubes do not necessarily have the same diameter. In most cases, the thermal tubes are dimensioned with a larger cross section to the

Volume loss of the reaction space by the preferred in

Center of the thermal tubes arranged to compensate for temperature measuring device. In the practical implementation, it is often not possible, the reaction volumes of normal and

Run the same thermo tubes.

According to one embodiment, the tubes have a wall thickness in the range of 1 to 3 mm. The tubes preferably have a circular cross-section. But it is also possible to use tubes with a different cross-section,

for example, an oval or a rectangular

Cross-section. Preferably, all tubes of a group have the same cross-section. However, it is also possible to provide tubes of different cross section in the reactor device. The inner diameter of the normal tubes is

preferably in the range of 15 to 35 mm, selected according to a further embodiment in the range of 15 to 30 mm. Of the

Inner diameter of the thermal tubes is usually chosen larger. Preferably, the inner diameter of the thermal tubes is selected in the range of 15 to 50 mm.

Both in the first group G _m of pipes and in the second group G _n of pipes, a reaction section S is defined, which preferably has the same dimension in both groups of pipes. In itself, the reaction path

Thermo tube and normal tubes are also chosen differently and, for example, in each case the entire length Include catalyst bed. The reaction path is preferably positioned the same for both groups of tubes relative to their gas inlet and gas outlet side, so that in the thermal tubes measurements can be carried out, which is a representative measurement of the temperature profile in the

Normal pipes allow. In this way, the

Temperature profiles in normal pipes and thermal pipes are approximately equal. According to one embodiment, the reaction path S thus comprises a section provided in all tubes, which in each case with corresponding

 Catalyst bodies is filled and in which an approximately the same temperature profile can be set for all tubes. The similar arrangement of the reaction path S in thermal and normal pipes is advantageous, for example, if the majority of the reaction takes place in the catalyst bed near the gas inlet side, ie the predominant part of the heat development near the gas inlet side in

Catalyst bed takes place while in the further course of

Catalyst bed, for example, only an optimization of

Composition of the reaction products is carried out without a comparable heat of reaction occurs as in the main reaction near the gas inlet. The reaction path S in the normal tube and in the thermal tube should thus comprise approximately the same reaction profile in the catalyst bed. The reaction zone S may comprise the entire filling height of the catalyst bed. But it is also possible to choose a reaction path S, which is smaller than the total distance, which is provided by the catalyst body within a tube in the longitudinal direction, ie ultimately the filling height of the catalyst bed in

relevant pipe. However, a statement about the

Temperature course to be able to meet in the entire normal tube, the reaction distance is preferably selected so that it is at least ten times the radius of the normal tube, preferably at least 100 times the radius of the normal tube equivalent. According to one embodiment, the reaction path S comprises at least 50%, according to another

Embodiment at least 70% and according to another

Embodiment at least 90% of the length of the catalyst bed in the tubes. In this case, the length of the catalyst bed, viewed in the flow direction of the reaction gas, means a section in the tube which is filled with catalyst bodies in all tubes within the reactor. However, it is also possible to arrange ^a plurality of reaction sections S ^a in the reaction tube in order, for example, to image a specific activity profile of the normal tubes in the thermotube.

Through the reaction path S is on the one hand

Volume section defined in the standard tube or in the thermal tube. For a normal pipe with a circular cross-section, which contains no internals, the volume section would calculate according to (r ^N _a ) ^{2 χ} π ^χ S, where r ^N _{a means} the inner radius of the normal pipe. For a thermal tube, which comprises an inner protective tube with a likewise circular cross section for the temperature measuring device, the

Calculate volume fraction to S ^χ π ^χ ((r ^T _a ) ² - (r ^T i) ² ), where r ^T _{a stands} for the inner radius of the outer tube and r ^T i for the outer radius of the inner protective tube. In the thermal tube, in this embodiment, the volume portion has the shape of a hollow cylinder. On the other hand, a wall surface W is defined by the reactor section S in both tubes. For a circular cross section, the wall surface for the normal pipe is 2nr ^N _a ^χ S, where r ^N _{a is} the inner radius of the normal pipe and 2nr ^T _a ^χ S for the thermal pipe, where r ^T _{a is} the inner radius of the outer pipe. The available in the normal tubes and the thermal tubes, defined by the reaction path S.

Volume section is filled with catalyst _bodies K _mjn . The shape and the composition of the catalyst body is initially not subject to any restrictions. Thus, the catalyst bodies within a section can be the same

Have shape. Two catalyst bodies have the same shape if they are the same shape, the same

Have dimensions and the same composition. But it is also possible, differently designed

 To provide catalyst body in the section. Likewise it is not necessary that in the normal pipes and the

Thermal tubes of the same catalyst, in particular a

Catalyst is used with the same composition. The only requirement is that the im

Thermotube introduced catalyst over the length of the

Thermotube shows such an activity curve that a temperature profile is generated, as it is approximately produced in the normal tube.

In the determined by the reaction path S.

Volume sections of the normal tubes and the thermal tubes provided catalyst activities are so

wobei bedeutet: tuned to satisfy the following equation:

where:

A _m : a catalyst activity in which by the

Reaction section S certain volume section in the tube from the first group G _{m is} provided

A _n : a catalyst activity in which by the

Reaction section S certain volume section is provided in the tube from the second group G _n ,

W _m : an inner surface of the tube from the first group G _m , which is determined by the reaction path S,

W _n : an inner surface of the tube from the second group G _n , which is determined by the reaction path S, a: a correction factor selected in the range of 0.8 to 1.2.

The correction factor a takes into account a deviation of a real reactor from an ideal reactor. In an ideal reactor with an ideal bed of catalyst particles, a would assume the value 1. But because, for example

Fluctuations in the bed of the catalyst body K _mjn both within a tube and when comparing different tubes of the same group and thus deviations of

Catalyst activity between different pipes

can be unavoidable by the correction factor a

Compensation can be created, these deviations

considered. It is advantageous if the correction factor deviates as little as possible from the value 1. According to a preferred embodiment, the correction factor a is in a range of 0.9 to 1.1.

The provided in the volume section

Catalyst activity A _{b is} calculated according to the equation

A _b = Α \ · M _b where:

A ^x _b : an active-mass-related activity constant of the first order of a catalyst body K _b provided

 Active material,

M _b : the mass of the volume of the catalyst bodies K _b in the defined by the reaction section S volume of the

Tube provided active mass,

b: an index selected from n and m and designating the catalyst body K _b in the volume section of the pipe defined by the reaction section S. In the practical implementation of experimental

Determination of Catalyst Activity A _b is determined according to a Embodiment proceeded so that a catalyst body is produced with a certain geometry and a certain content of active material. Further, it is believed that the first order reaction proceeds regardless of the order with which the reaction actually proceeds. The product of the rate constant k of a first-order reaction and the average residence time τ corresponds to the first

Damköhler number Dai, which essentially describes the turnover of a simple reaction in a reactor. Will for the

Catalysts in normal and thermal tubes the same

 Active mass, the rate constant k is the same for both catalysts.

This standardized catalyst body is then diluted in a test reactor with inert bodies so far that the temperature difference between the gas inlet and the

 Gas outlet side is less than 25 ° C, preferably less than 10 ° C, the reaction under almost isothermal

Conditions run, wherein the pressure drop across the reactor is less than 30 mbar, preferably less than 10 mbar and wherein the conversion is adjusted to a value in the range of 65 to 95%.

For this purpose, the catalyst body is diluted with inert bodies. The geometry of the catalyst body and the inert body is chosen so that the required low pressure drop is realized. The ratio of inert bodies to catalyst bodies is chosen so that the required conversion is achieved and at the same time the heat development is so low that the required low temperature difference between gas inlet and gas outlet is maintained. Based on the volume, which results from the bulk density of the catalyst body or the inert body, a ratio of catalyst bodies to inert bodies of 1: 5 to 1: 10 is preferably selected. The dimensions of the test reactor will vary depending on the considered reaction between 1 and 6 m for the length and between 18 and 32 mm for the diameter of the tube chosen. In fast reactions, a short length is chosen

while for slow reactions a larger

Reaction distance is needed to achieve the required sales.

It is then defined at different defined space-time speeds and at various defined

Temperatures measured the conversion of the reaction, which is catalyzed by the active composition of the catalyst body. From the sales can then be the mass-related

Activity constant 1st order A ^{* of} the active mass in

Calculate the dependency on sales according to the following formula:

[GHSV x -1 x ln (l - U) \

 A * = j j

\. ^m Aktivmassel

Where: A ^* : the mass-related activity constant 1st order of the

 Active mass at a certain temperature and GHSV;

GHSV: the space-time velocity [h ^_1 ]

mActive mass: the amount of active mass [g] introduced in the test tube; U: the conversion of the educt, whereby this is calculated

 to

Mrein ^~ ^ out

 Mrein

Where:

Mr _e in: Amount of starting material [mol] which of the catalyst charge

 is supplied

M _out : amount of starting material [mol] which the catalyst filling

leaves From the determined mass-related activity constants of the first order A ^{* of} the active mass, the active mass-related activity constant of the first order A ^x _b is then defined

Reference sales determined. This reference turnover is chosen such that this turnover is in the linear range of

 Dependence of the mass-related activity constant 1.

Order A ^{* is} the active mass of the conversion. For example, a turnover of 85% can be set as a reference. The calculated for a turnover of 85%, for example

active mass-related activity constant 1st order is then referred to as active mass-related activity constant 1st order A ^x _b . As such, another value for sales can be set. The value should be however at the

intended technical implementation. According to one embodiment, the value of the conversion for determining the active mass-related activity constant 1st order A ^x _{b is selected} within a range which is ± 20% of the conversion at which the reaction in question is technically implemented, the conversion being within a range of the curve of

active mass related activity constant and turnover is approximately linear.

From the active mass-related activity constants of the first order A ^x _b determined in the test reactor described above, it is then possible to multiply by mass with the mass of the active mass within the volume section of the pipe G _m or G _n defined by the reaction section S.

is provided, which provided in the volume section defined by the reaction section S.

Calculate catalyst activity A _b . The thermal tubes provided in the reactor device

include a temperature measuring device, with which the temperature or the temperature profile can be determined in the thermal tube. This can be any measuring devices be used. Preferred are those

 Temperature measuring devices used, the determination of the temperature profile over the reaction path S away

enable. For this purpose, for example, be provided that at certain intervals within the thermal tube

Temperature sensors are provided with which the temperature can be measured at defined locations of the tube. But it is also possible, for example, a movable

Provide temperature sensor with which a relatively accurate determination of the temperature profile along the longitudinal axis of the thermal tube is possible. In particular, in an industrial application it is provided that the temperature measuring device is designed as arranged along the longitudinal axis of the thermal tube tube, in which at least one temperature sensor is arranged. Through the pipe, the temperature sensor is protected from damage. It is preferably provided that the temperature sensor is designed so that it is in the pipe

can be moved. In this way, a temperature profile in the flow direction can be recorded in the thermal tube. In this embodiment, a volume portion which forms the shape of a hollow cylinder is formed between the wall of the thermal tube and the wall of the thermowell thermowell arranged in the thermowell.

The catalyst bodies K _m , K _n may in themselves have any desired shape, wherein different catalyst bodies can also be combined with one another within a tube. Be within a tube of a catalyst bed

Catalyst bodies of different shapes used, but this can during filling to a partial or

Complete demixing lead the differently shaped catalyst body. This would result in an inhomogeneous activity history, which is why the possibility

is that the temperature profile, as measured in the thermal tube, no longer representative of the Temperature course in the normal pipe is. According to a preferred embodiment, it is therefore provided that the

Catalyst body K _m , K _n in the volume section defined by the reaction section S a homogeneous bed

form. A homogeneous bed is understood to mean a bed whose bulk density, measured over the length of the relevant pipe, deviates from the mean

(arithmetic mean) of not more than 20%, preferably not more than 10% and in one embodiment not more than 5%. If catalyst bodies of different geometry are used within a common catalyst bed, a homogeneous bed can be achieved by, for example, the differently shaped

Catalyst bodies are filled in a particular arrangement or sequence in the pipe in question, so that a

defined distribution of the different catalyst body is achieved within the catalyst bed arranged in the tube.

According to a preferred embodiment is in the

Reactor device according to the invention provided that the

Catalyst body K _m and the catalyst body K _n in the volume section defined by the reaction section S each have a homogeneous shape. In this embodiment, it is thus provided that the catalyst bodies each have a tube the same properties, ie

for example, have the same shape, the same

Composition of the active composition, the same amount

Active composition etc. However, it is not necessary that the catalyst body K _m and the catalyst body K _n a

have homogeneous shape to each other, ie the same in both the normal tubes and in the thermal tubes

Catalyst body are arranged. Rather, it is generally provided that the catalyst body K _m and the

Catalyst body K _{n are} different, so for example have a different shape, in the

Different composition of the active composition or

For example, include a different amount of active material. The catalyst _bodies K _mfn used in the reactor _device can be designed as solid catalysts, that is, for example, over their entire volume a homogeneous

Have composition.

According to a preferred embodiment, it is provided that the catalyst body K _m and the catalyst body K _n as

Supported catalysts, in particular as shell catalysts, are formed with a layer of the active composition. The supported catalysts can be designed in the usual way. The supported catalysts may comprise a carrier body which may have any desired shape. The support body may for example have the shape of a ring, a ball or a hollow cylinder. Support bodies in the form of a hollow cylinder are preferred. Preferably, the

Hollow cylinder has a length in the range of 2 to 10 mm, according to one embodiment in the range of 4 to 8 mm. According to one embodiment, the hollow cylinders have a

Outside diameter in the range of 3 to 8 mm, according to another embodiment of 4 to 7 mm. The wall thickness of the hollow cylinder is preferably in the range of 0.5 to 4 mm, according to one embodiment in the range of 1 to 2 mm

 Exemplary dimensions for suitable hollow cylinders are 8 x 6 x 5 mm, 7 x 7 x 4 mm, 7 x 4 x 4 mm and 6 x 5 x 4 mm

(Outer diameter x length x inner diameter). According to one embodiment, hollow cylinders are suitable, the one

effective diameter in the range of 4 to 10 mm, according to another embodiment in the range of 5 to 8 mm. Under an effective diameter is doing the arithmetic mean of length and outside diameter of the

Carrier body understood.

The carrier bodies are preferably constructed of a material which has a very low porosity, for example a porosity of less than 1 ml / 100 g. The carrier bodies may be made of conventional materials, for example porcelain, quartz, magnesium oxide, zinc dioxide, silicon carbide, rutile, alumina (Al ₂ O ₃ ), aluminum silicate, magnesium silicate (steatite), zirconium silicate or cersilicate or aus

Mixtures of said materials. On the carrier body, a layer of the active material is arranged. The active material may additionally contain other materials,

for example, a binder. The active mass is

selected according to the reaction carried out in the reactor apparatus according to the invention.

The layer thickness of the applied on the support body shell of the active material is according to one embodiment between 10 and 800 pm and according to another embodiment

chosen between 50 and 500 pm. In reactions with very fast kinetics, often

diffusion limit can be limited, the layer thickness of the applied on the carrier body shell is preferably low

chosen so that, for example, in Oxidationsreakt ions, the Part ialoxidat ion against the Totaloxidat ion is strongly preferred.

In order to achieve a good control of the reaction, it is provided according to an embodiment that the amount of

Active mass, which in the through the reaction path S

certain volume portion is provided, based on the tube wall area of the section in the range of 0.01 to 1 g / cm ² , according to one embodiment in the range of 0.02 to 0.08 g / cm ^{2 is} selected. According to one embodiment, both for the

Catalyst body of the normal tubes as well as for the

Catalyst body of the thermal tubes used the same active mass, the catalyst activity can be adjusted in normal tubes and thermal tubes on the amount of active mass in the tube in question within the by the

Reaction distance S certain volume section is provided.

Substituting the ratio of the mass of active mass to

Pipe wall surface, which is for normal pipe and thermal pipe

is determined in relation to each other, this is according to one embodiment in the range of 0.8 to 1.2, according to another embodiment in the range of 0.9 to 1.1.

In this embodiment, therefore:

(Wrn where:

M _m : the mass of the active mass in which by the

Reaction section S certain volume section in the tube from the first group G _{m is} provided

M _n : the mass of the active mass in which by the

Reaction section S certain volume section is provided in the tube from the second group G _n ,

W _m : an inner surface of the tube from the first group G _m , which is determined by the reaction path S,

W _n : an inner surface of the tube of the second group G _n , which is determined by the reaction distance S, a: a correction factor, which is selected in the range of 0.8 to 1.2. In one embodiment, a is chosen in the range of 0.9 to 1.1.

The im defined by the reaction path S.

Volume section of the relevant pipe available

Asked catalyst activity can according to a

Embodiment when using coated catalysts, for example, be adjusted by the fact that the active material of the catalyst body K _m , K _{n has} a same composition and the activity A _{b is} determined by the layer thickness of the applied on the support body active mass. In this embodiment, therefore, the amount of active material which is provided in the volume section of the tube, determined by the layer thickness of the active composition. A higher one

Layer thickness makes it possible to use a higher amount

To provide active composition and thus a higher

Catalyst activity A _b with otherwise identical

Reaction conditions. In this embodiment, therefore, the active mass provided by the catalyst bodies K _m , _n respectively has the same active mass-related activity constant 1 st order, so that the adjustment of the catalyst activity in the volume section of the pipe determined by the reaction section S is effected via the amount of active mass provided.

However, according to further embodiments, the activity can also be adjusted by the active mass-related

Activity constant 1st order A ^x _{b is} adjusted. For this purpose, for example, the composition of the active composition can be changed, for example by adding promoters or moderators to the active composition. The concentration of

Promoters or moderators in the active composition can be chosen differently in the catalyst bodies K _m , K _n .

An adaptation of the active mass-related activity constant order A ^x _{b of} the active mass and thus within the volume section determined by the reaction section S. However, provided catalyst _activity Α _{Τ [1ιΤ1} can also take place, for example, that the pore volume of the active composition for the catalyst body K _m , K _n is chosen differently. For this purpose, for example, the pore volume of individual components of the active composition can be adjusted.

A further embodiment achieves an adaptation of the active mass-related activity constant of the first order A ^x _b by the adaptation of the crystallite size of the active mass in the

Catalyst body K _m , K _n . In itself, the skilled person can adapt the

 Catalyst activity in the volume sections of the normal pipe or the thermal tube to resort to all measures resulting in a modification of the active mass

Activity constant 1st order A ^x _{b of} the active material lead. According to a further embodiment, the adaptation of the catalyst activity A _m , _n provided in the volume sections is achieved by virtue of the fact that the catalyst bodies K _m , K _{n have} a different geometry. The catalyst body in the normal tubes and the thermal tubes can have the same shape in both tubes, for example, balls or hollow cylinders, wherein the dimensions of the moldings in the

Normal pipe and in the thermal tube, however, are chosen differently. Thereby, the effect can be exploited that smaller catalyst body has a higher geometric surface

and as a rule such a greater bulk density can be obtained. Become for example spherical

Catalyst selected, the amount of active material in the volume section determined by the reaction section S can be increased by using smaller balls with the same layer thickness of the active mass. But it is also possible to provide in the determined by the reaction section S volume portions of normal and thermal tube catalyst body, which differ in their shape. According to one embodiment, shell catalysts are used, wherein the shell catalyst takes the form of a

Hollow cylinder has. In order to modify the amount of active material that is provided in the volume section determined by the reaction section S, then carrier bodies can be used, which have a smaller inner or

Outer diameter or a shorter length than the carrier body of the catalyst body in the tubes of the other group. But it is also possible that the catalyst body in

 Thermal tube and normal tube are chosen completely different, so for example in a tube, the catalyst body having the shape of hollow cylinders while in the other tubes, the catalyst body having the form of balls. According to a further embodiment, it is provided that the adaptation of the catalyst activity provided in the volume section determined by the reaction section S takes place by adding inert bodies to the catalyst bodies. If identical catalyst bodies are used in the volume sections determined by the reaction section S, the catalyst activity can be adjusted by the fact that the catalyst bodies in one of the tubes are replaced by the addition of

The inert bodies can have the same shape as the catalyst bodies or else have a different form from them.

Finally, it is also possible the ones described above

Combine action to the required

Catalyst activity to achieve.

The reactor device according to the invention can be designed so that in the normal tubes and the thermal tubes the

Bed throughout the entire length of the catalyst bed each having homogeneous properties. In this embodiment So is only one reaction path S in the normal pipe or

Thermo tube provided.

According to a further embodiment, it is provided that more than one reaction section S is provided in the tubes of the first group G _m and in the tubes of the second group G _n , the reaction sections S ^a respectively defining volume sections in the tubes, and in the volume sections

different catalyst body K ^a _m , Κ ^α _η are arranged, each case denotes a layer in the tubes of

Groups G _m and G _n in which the respective reaction section S ^{a is} arranged. For example, are three layers of

Arranged catalyst bodies in the normal tubes or the thermal tubes, so called the first, second or third layer, so here assumes the values 1, 2 and 3, respectively. In general, an index which can take the value of integers between 1 and the number of layers of catalyst bodies present in the reaction tube.

Such an embodiment corresponds to a

Catalyst bed comprising a plurality of layers, wherein the catalyst bodies contained in the individual layers are selected differently. This way you can

certain activity profile can be set in the normal tube and thereby controlled, for example, the formation of by-products or a total oxidation can be suppressed. In each individual shift then an adaptation of the

Normal pipe or provided in the thermal tube

Catalyst activity, so that by the

Use of different catalyst body formed in the normal tube formed temperature profile in the thermal tubes accordingly.

According to one embodiment, the tubes of the group G _m or G _n each comprise at least two reaction sections S ^a , according to a further embodiment, at least three Reaction sections S ^a and according to yet another

Embodiment at least four reaction sections S ^a . According to one embodiment, precisely two reaction sections S ^a , in each case exactly exactly three reaction sections S ^a are arranged in the tubes ^, and exactly four reaction sections S ^a are arranged according to a further embodiment. The length of the individual reaction sections S ^a can be chosen equal or different within a tube. However, between the various groups G _m , G _n of tubes, the corresponding reaction sections S ^a are preferably selected to be the same length, so that a

Illustration of the temperature profile generated in the standard tube in the thermal tube is possible.

Within the tubes of a particular group, the various reaction sections S ^a then comprise regions that provide different catalyst activity.

In the reactor device according to the invention is the

modified residence time T _m0 d adjusted so that they

within normal error limits and technical variations for all tubes is substantially the same.

In this case, according to one embodiment, the procedure is such that a layer of inert bodies is provided in a first working step for setting the pressure drop of all normal tubes, in particular for increasing the pressure drop. These

Inert bodies preferably have a different geometry than the catalyst body. For example, to increase the pressure drop, a layer of sand can be provided, whereby the pressure drop can be increased. This layer off

Inert bodies are preferably provided on the gas exit side of the catalyst bed. If the pressure drop in one of the tubes is to be reduced, it is also possible to proceed in such a way that the length of the catalyst bed arranged in the relevant tube is shortened. The Reaction path S can then optionally be adapted to the shortened catalyst bed. The normal _tubes are now set to a certain modified residence time ^~ u _m0d .

The modified residence time ^~ u _{m0d of} the thermal tubes is now adjusted in a second step to this in advance

Normal pipes adjusted. The modified residence time ^~ u _m0d can _then be calculated via the amount of gas passed through the catalyst _{bed of} the relevant pipe. The modified one

_Residence time ^~ u _m0d can be adjusted by adding or removing catalyst bodies until the desired

modified residence time ^~ u _{m0d is reached} for the thermal tubes.

In the practice, in a reactor consisting of a bundle of a plurality of reaction tubes, by measuring the catalyst fill height and the pressure drop of each tube, it is ensured that a) no misfillings

(empty tubes, bridge formation, etc.) occur and b) the modified residence time T _m0d in all tubes of a group, ie normal tubes, is substantially identical within the metrological tolerance. To be as ideal as possible when filling a

To achieve technical reactor is according to a preferred embodiment, proceed as follows:

1. All normal pipes are filled. In this case, it is determined for a reference ensemble of tubes (for example 200 tubes) which bulk densities with which

 Standard deviation in the normal tubes are present. For these reference tubes also the pressure drop and its standard deviation is determined.

2. When all tubes are filled, the dump height will be in all

Measured tubes to ensure that the same volume of catalyst is filled in all tubes. (tolerated Deviation +/- 1.6 - 2.3% of the dumping height. Misfed pipes are emptied and refilled.

3. If all tubes are checked and corrected as above, the pressure drop of all normal tubes is measured and the standard deviation determined. The pressure drop of all

 Normal pipes should not exceed 7% of the mean

 differ. Pipes with larger or lower

 Pressure drops are emptied and refilled.

4. Only when all normal pipes filled, controlled and

 may be corrected, the thermal tubes are filled, controlled and adjusted using the critical parameters determined for the normal tubes.

By using a corresponding active mass, the reactor device can be adapted per se to all reactions that are accessible to heterogeneous catalysis.

Preferably, the reactor apparatus is used for such reactions which are carried out in the gas phase. According to one embodiment, the reactor apparatus for

Used reactions that are diffusion-controlled and for which according to one embodiment, for example

Shell catalysts can be used. The reactions can be both exothermic and endothermic.

Accordingly, by the in the reactor device

provided heat transfer medium either heat from the

Reactor device be discharged when the reaction

exothermic or heat may be supplied if the reaction is endothermic. The reactor device according to the invention is particularly well suited for carrying out exothermic reactions, such as oxidation, dehydrogenation,

Hydrogenation and oxydehydrogenation reactions, wherein as

Examples are the preparation of phthalic anhydride from o-xylene, from acrolein from propene, from acrylic acid from propene / acrolein, from methacrylic acid from methacrolein, from methacrolein i-butene, from acrylonitrile from propene, from formaldehyde from methanol, from ethylene oxide from ethylene or the production of maleic anhydride from butane.

According to a preferred embodiment, the

Reactor device according to the invention for the production of phthalic anhydride from o-xylene and / or naphthalene

set up. It can in itself to known

 Reactor devices and catalysts for the production of phthalic anhydride by oxidation of o-xylene and / or

Naphthalene be resorted to.

The filling of the reactor device or the adjustment of the catalyst activity in the normal tubes and the

However, thermal tubes are made according to the reactor apparatus described above. The partial oxidation of o-xylene and / or naphthalene to

 Phthalic anhydride can be carried out in such a way that in the normal tubes or the thermal tubes only a single layer formed from the catalyst bodies

is arranged. In particular, in the partial oxidation of o-xylene and / or naphthalene for the preparation of

 However, phthalic anhydride is preferred to arrange several layers of different catalysts in the tubes, wherein the catalysts of the provided in a tube layers, for example, in their composition and

especially in their activity. This makes it possible to suppress the formation of by-products, for example phthalide. The adaptation according to the invention arranged in the other group of tubes

Catalyst body then takes place for each layer according to the principles described above.

The catalysts used for the production of phthalic anhydride are preferably based on vanadium pentoxide and Titanium dioxide. The titanium dioxide is generally used in the

Anatase modification used and has a specific surface area in the range of 10 to 50 m ² / g. In addition to the

Components mentioned may contain conventional other components in the active composition, whereby the activity of the

 Catalyst can be adjusted in the desired manner. The composition of the active composition is preferably selected in the following ranges:

V ₂ 0 ₅ 1 to 25% by weight

Sb ₂ 0 ₃ 0 to 4 wt.

 O

 Cs 0 to 1% by weight

 P 0 to 2 wt .-% o · In addition to these components, other common

 Compounds may be contained in the active composition, with which the activity of the catalyst can be modified. Such compounds include compounds of the alkali and alkaline earth metals, thallium, antimony, iron, niobium, cobalt, molybdenum, silver, tungsten, tin, lead and bismuth. In the active form of the catalyst, these elements are usually in the form of their oxides. The proportion of these metals, calculated as the most stable oxide and based on the active composition in its active form, is preferably in the range of 0 to 3 wt .-%, preferably 0 to 2 wt .-%. The elements mentioned or their

Oxides may be present alone or in the form of a mixture in the active composition. The missing to 100 wt .-% proportion of the active composition, based on their activated oxidic form, is preferably formed by T1O ₂ , which is preferably present in the anatase modification. The T1O ₂ preferably has a BET surface area of at least 15 m ² / g, more preferably a BET surface area of between 15 and 60 m ² / g, in particular a BET surface area of between 15 and 45 m ² / g and particularly preferably between 15 and 40 m ² / g. If the reactor device according to the invention for a

Application designed for the gas phase oxidation of o-xylene and / or naphthalene, the catalyst bodies are preferably provided as shell catalysts. Such a shell catalyst comprises an inert

 Carrier which is inert under the reaction conditions. Suitable materials and shapes for the carrier bodies have already been described above. On the carrier body, the active composition is applied in the form of a thin layer. The layer thickness of the applied to the carrier body

Active composition is preferably in the range of 50 to 500 pm

selected. The active material may be applied in the form of a single layer. It is also possible to have two or more layers of the same or different

to provide composite active masses on the carrier body.

To obtain a high yield of phthalic acid and the

In order to suppress the formation of by-products, several layers of catalyst bodies are preferably arranged in the tubes of the reactor apparatus according to the invention, wherein the individual layers within a tube differ in their activity.

According to one embodiment, the gas inlet side layer has the lowest catalytic activity. The adjoining to the gas outlet side

Layers then have an increasing catalytic activity, so that the gas outlet side arranged layer has the highest catalytic activity.

In addition to an activity profile in which the catalytic activity in the direction from the gas inlet side to

Gas outlet side gradually increases, also a different activity profile can be selected. For example, at first a layer may be provided for the gas inlet side, the catalytic activity of which is higher than the catalytic activity of the layer which adjoins in the direction of the gas outlet side. In the inventive

Reactor device reflects the activity profile, as it is adjusted for example in the normal tube, in

 Activity profile of the thermal tube again, so that in the

Thermal tube measured temperature profile for the

Temperature distribution in the standard pipe is representative.

Be in the partial oxidation of o-xylene and / or

Naphthalene to phthalic anhydride multiple layers

different catalyst body arranged in a tube, the expansion of the individual layers is preferably selected in the range of 30 to 200 cm, the arrangement of the catalyst layers as a whole an expansion in

Lengthwise of the tubes of preferably between 2 and 3.50 m.

In the reactor device according to the invention is the

Catalyst activity in the tubes of the two groups G _m , G _n adapted according to the formula described above. For this purpose, the measures already described above can be carried out. To an increase in the catalyst activity in the relevant defined by the reaction path S.

Volume section can be reached by the

Reaction section S certain volume section is provided a higher active mass content than in the tubes of the other group. However, it is also possible to increase the activity of the active composition directly by, for example, the active composition having a higher vanadium content and / or a lower Sb content and / or a lower Cs content. To increase the activity of the active composition, a T1O ₂ with a higher BET surface area can also be provided. Furthermore, promoters can be added to the active composition or their proportion can be increased, which increase the activity of the active composition. Similarly, the proportion of attenuating promoters in the

Active mass to be lowered.

To increase the active material content in the volume section, for example, the layer thickness of the active composition on the

Carrier body can be increased. However, it is also possible to change the geometry of the carrier body in such a way that the bulk density is increased. Combinations of these measures are also possible.

According to a further embodiment, the reactor device according to the invention for the production of acrolein by oxidation of propene and / or acrylic acid from acrolein, or for the production of methacrolein by oxidation of isobutene and / or methacrylic acid from methacrolein

set up. Also in these reactions can be per se known reactor devices and catalysts for the

Production of acrolein and acrylic acid by oxidation of propene or acrolein or for the production of methacrolein and methacrylic acid by oxidation of isobutene or

Methacrolein be resorted to. The filling of the

Reactor device or the adaptation of the catalyst activity in the normal tubes and the thermal tubes, however

corresponding to the reactor device described above

performed .

As already described in the partial oxidation of o-xylene and / or naphthalene, even in the partial oxidation of propene or isobutene or of acrolein or methacrolein, a single catalyst layer in the normal tubes or the

Thermo tubes may be provided. But it is also possible to arrange several layers of catalysts in the tubes, the composition and thus the activity of the

Catalysts in the individual layers is different. For the partial oxidation, both unsupported catalysts and coated catalysts can be used. To the

Catalyst activity can be adjusted when using full catalysts, for example, catalyst bodies with different geometry can be used, so that ultimately the bulk density of the catalyst body in normal and

Thermo tubes is different. Alternatively, the

Active mass can be diluted with an inert material to adjust the catalyst activity in the respective tube can. Finally, the catalyst bodies can also be diluted with inert bodies in order to adjust the catalyst activity in the respective tube to a specific value, so that the ratio of the catalyst activity of the standard pipe and the thermal tube is set to the desired value with an otherwise comparable modified residence time T _m0 d- Shell catalysts can the

 Catalyst activity can be adjusted with agents, as described above, so for example by adjusting the layer thickness of the active material layer on the inert support body.

As the active composition can be used as catalyst masses, as they are already known from the prior art. Suitable catalysts for the Partialoxidat ion of propene and isobutene for the production of acrolein or methacrolein based for example on molybdenum and

Bismuth. A suitable catalyst is described, for example, in DE 23 38 111 C2. This has a composition of the formula Mo ^ Bi _a Me ^ Me ^ Me ^ Me ^ Me ^ Zn _h O _g on which means: Me ¹ : In and / or La;

Me ² : Fe and / or Cu;

Me ³ : Ni and / or Co;

Me ⁴ : at least one element from the group P, B, As, Cr, V and / or W;

Me ⁵ : at least one element from the group Cd, Ta, Nb, Ag,

 Pb, Mn, Re, Mg, Ca and / or Ba;

a: 0.1 to 6, preferably 0.5 to 3;

b: 0.005 to 3, preferably 0.01 to 2;

c: 0.1 to 8, preferably 0.3 to 6;

d: 4 to 12;

e: 0 to 6, preferably 0.05 to 5;

f: 0 to 3;

g: 36 to 102, preferably 38 to 95;

h: 0.1 to 10, preferably 0.5 to 6.

The dimensioning of the reactor, that is, for example, the number of tubes and their dimensions can be selected analogously to the parameters described above.

According to a further aspect, the invention relates to a

Method of providing a reactor apparatus as described above. The reactor apparatus comprises at least a first group G _m of pipes comprising at least one normal pipe and a second group G _n of pipes comprising at least one thermal pipe provided with a temperature measuring device.

In a group G _p of pipes formed by the first group G _m or the second group G _n of pipes, catalyst bodies K _{p are} filled so that at least one volume section of the pipe determined by a reaction section S is filled with the catalyst bodies K _p , In providing the above

Reactor device can thus either first the

Normal tubes filled and then the filling of the thermal tubes are adapted by providing appropriate catalyst bodies are provided. But it is also possible first to fill the thermal tubes with catalyst bodies, and then to adjust the filling of the normal tubes by appropriate

Catalyst body can be selected. For practical reasons, the catalyst bodies are preferred for the first

Filling the normal tubes selected, and then provided appropriate catalyst body to fill the thermal tubes.

In that determined by the reaction path S.

Volume section of the pipe from the group G _p becomes a

Catalyst activity A _p determined.

In a group G _q of pipes which do not belong to the group G _p , catalyst bodies K _{q are} filled, wherein the catalyst bodies K _{q have} an activity such that in a volume section of the pipe from the group G _q determined by the reaction section S a catalyst activity A _{q is} obtained, where: W

VW where:

A _p : a catalyst activity in which by the

 Reaction distance S certain volume section in one

Tube is provided from the group G _p ,

A _q : a catalyst activity in which by the

Reaction section S certain volume section is provided in a tube from the group G _q , W _p : an inner surface of the tube from the group G _p , which is determined by the reaction path S,

W _q : an inner surface of the tube from the group G _q , which is determined by the reaction distance S, a: a correction factor which is in the range of 0.8 to 1.2

is selected, wherein the catalyst activity A _d calculated according to

A _d = A 1. M _d where

A ¹ _d : an active mass-related activity constant of the first order of an active composition provided by the catalyst body K _d ,

M _d : the mass of the active material provided by the catalyst bodies K _d in the volume section of the tube defined by the reaction section S, d: an index which is selected from p and q and the catalyst body K _d in the volume section of the volume defined by the reaction section S. Designated tube.

The in the pipes of the group G _p and in the pipes of the

G _q generated pressure drop and the modified residence time T _{mod of} the gas is then adjusted according to an embodiment to a substantially same value.

According to one embodiment, the procedure is first of all to determine the pressure drop or the back pressure of all the pipes of the group G _p , for example the normal pipes, and thus by adding inert material (pressure increase) or by removing catalyst particles (pressure decrease) adapts all pipes of group G _{p have} substantially the same back pressure or pressure drop, preferably a maximum deviation from Mean value of up to +/- 7%, according to one embodiment of up to +/- 5% is achieved.

Subsequently, the reaction tubes G _{q of} the other group, for example, the thermal tubes with the

Filled thermocatalyst and the modified residence time ^~ u _m0 d of the thermal tubes and the normal tubes adapted so that both groups of tubes G _p and G _{q have} a substantially same modified residence time T _mod .

A substantially equal value is understood to mean a value which does not deviate more than 10%, preferably not more than 5%, from the mean (arithmetic mean), measured over all tubes.

Thus, in the method according to the invention, first of all a reactor device with two groups of tubes is provided. The tubes comprise a first group G _m of tubes comprising the normal tubes. The second group G _n of tubes comprises the thermal tubes. When loading the pipes with the

Catalyst bodies is first selected a group of pipes, so either the group G _m of pipes, the

comprising at least one normal pipe, or the second group G _n of pipes, which comprises at least one thermal pipe provided with a temperature measuring device. The selected group of pipes then forms the group G _p and the other group of pipes forms the group G _q in the sense of the method according to the invention. Preferably, the normal tubes, ie the first group G _m of tubes with catalyst bodies are first loaded. All pipes of the group can be loaded. In this embodiment, therefore, the group G _m of pipes would form the group G _p according to the method according to the invention.

Advantageously, however, proceed in the way that

first at least one representative tube, preferably a group of at least 100-200 tubes selected and this is loaded with the corresponding catalyst bodies. It Then a reaction distance S is determined and determines the catalyst activity provided in the volume of the tube determined by the reaction section S. For this purpose, for example, from the bulk density of the catalyst body in the pipe in question and the proportion of the active mass on

 Catalyst body, the mass of the active mass are calculated, which is provided in the relevant section of the tube. Since the tubes usually have a relatively small cross-section, the bulk density is advantageous in the

representative group itself, so that effects that are caused by the arrangement of the individual catalyst body in the tube, are taken into account. From the one in the

Volume section provided provided

Active mass can be multiplied by the

corresponding active mass-related activity constant 1.

Order A ^x _{d determine} the catalyst activity A _p . Furthermore, from the length of the reaction path S and the radius of the pipe, the corresponding pipe wall surface W _p can be calculated.

In the next step, the catalyst activity A _q is then determined, which in the through the reaction path S

certain section must be provided in the tubes of the other group. For a first calculation, the correction factor a is set to the value 1 for this purpose. The active substance-related activity constant of the first order of the active material used in this tube can then be the quantity

Active mass to be introduced in the corresponding section of the tube, so that the above equation is satisfied. This active mass is then introduced into the tube via the corresponding catalyst bodies. The catalyst bodies are selected in such a way that at least that determined by the reaction path S.

Volume section of the corresponding tube is filled. For example, in one embodiment

 Shell catalysts used in the tube, can first by means of non-active catalyst bodies, for example, the carrier bodies themselves or by the carrier body

For example, be coated with a defined layer of a mass that has a comparable density as the active material, a bulk density of the

Catalyst body can be determined. From this bulk density can then be determined together with the calculated amount of active composition, a catalyst body containing the required amount of active material, which is necessary to provide the desired catalyst activity. The

Bulk density is also advantageously determined in this case directly in the corresponding tube to effects

take into account that are caused by the changed cross-section of the tubes in the arrangement of the catalyst body.

The identified and provided in this way

Catalyst bodies are filled after their preparation in the corresponding tube.

Since in the technical execution by fluctuations,

For example, in the cross section of the tubes or the shape of the catalyst body or by fluctuations in the

Bulk density of the catalyst body deviations are generated from the ideal state, in the implementation on an industrial scale of the final reactor device determined correction factor a usually no longer equal to 1, but differ slightly from this. A

satisfactory picture of the temperature profile in the

Normal pipe in the thermal tube is, however, in the experience of the inventors possible if the value of the correction factor a is in a range of 0.8 to 1.2, preferably 0.9 to 1.1. After filling of the tubes of the group G _q is analogous to the procedure described above for the tubes of the group G _p according to an embodiment for each individual tube of the group G _{q is} the modified residence ^~ u _m0 d determined by each preferably an inert gas stream by pipe in question is passed. According to the experience of the inventors, satisfactory values are achieved for a technical implementation if the setting of the modified residence time ^~ u _m0 d

simplified at room temperature with an inert gas is made. In itself, the adjustment could also be made, for example under reaction conditions. However, this is difficult in the technical design. To balance the

modified residence time T _m0 d of the pipes of group G _q (eg

Thermo tubes) is the ratio of the mean modified residence time T _m0 d of the group of eg 200th

Reference pipes of group G _p (eg normal pipes) and the

medium mod. _Residence time T _m0 d of the reaction _tubes of group G _q (eg thermal tubes). Subsequently, the

Volume flow calculated for a comparable

Modified residence time T _m0 d in the reaction _{tubes of} the group G _q (eg., Thermo tubes) is necessary. After setting this

Volume flow in the dynamic pressure gauge is the

 Back pressure / pressure drop of the catalyst bed using the o.g. Measures adapted until a modified

_Residence time T _m0 d is set, which corresponds to the average modified residence time T _m0 d of the reference standard pipes, ie the pipes of the group G _p .

By the already explained deviations from the ideal

Condition when implementing in technical equipment

are unavoidable, the bulk density, the

_Pressure drop / _dynamic pressure and the modified residence time T _m0 d also between tubes within the same group. The

Determination of pressure drop / dynamic pressure and modified _Residence time ^~ u _m0d therefore preferably takes place separately for each individual tube.

The pressure drop / _dynamic pressure and the modified residence time ^~ u _{m0d of} the gas is preferably determined with an inert gas,

for example air. The correction of the parameters is then carried out in the usual way. In order to reduce the pressure drop / dynamic pressure within a pipe, for example, the column length of the bed of the catalyst body can be shortened. This shortening of the catalyst bed is

Preferably, carried out at the gas outlet side, so in multi-layer catalyst arrangements preferably by shortening the gas outlet to the nearest layer of

Catalyst bodies. The shortened section can then

For example, be replaced by a corresponding support device that generates a very low pressure drop.

In order to increase the pressure drop / dynamic pressure within a column, a section can be provided in the column, which is filled with, preferably inert, bodies which generate a high pressure drop / back pressure. A suitable material is, for example, sand. This inert material will

preferably also arranged on the gas outlet side of the arranged in the tube bed of catalyst bodies. This can be done in the practical implementation of the first

Pressure drop / dynamic pressure are determined, which by the

Charging the tube with the desired amount of

 Catalyst bodies is generated. This can be a

Calculate difference to the desired pressure drop / dynamic pressure, which in turn the amount of inert bodies, such as sand, which is required to the desired

Pressure drop / back pressure to adjust, can be calculated.

If the tube flows through the reaction gas, for example, during operation from top to bottom, the catalyst body filled in the tube is first removed again, and then first the corresponding one on the gas outlet side Layer filled from the inert material. On this layer to correct the pressure drop / dynamic pressure are then

then again applied the previously removed catalyst body. Other methods to equalize the pressure drop / back pressure of the pipes are also possible. For example, catalyst bodies of a particular geometry can be used to achieve a desired pressure drop / dynamic pressure.

Similarly, the inert material on top of the

Catalyst bed are abandoned, so on the

Gas inlet side.

When filling the tubes of the reactor, the procedure is preferably that on the gas inlet side the

Catalyst bed in all tubes relative to

Reactor housing reached about the same level, so that for all tubes a comparable temperature profile in the

Implementation of the relevant reaction. If necessary, height adjustment can be achieved by providing supporting bodies which are arranged on the gas outlet side or the lower section of the tube, whereby these correction bodies only have a very small amount

Create pressure drop / dynamic pressure.

According to one embodiment, when laying a plane through the tubes which corresponds to the mean value of the deviations from the filling level, the distance between the plane and the upper termination of the filling of a tube is preferably not more than ± 7 cm, according to a further embodiment as ± 5 cm and according to yet another embodiment not more than ± 2 cm. The modified residence time ^~ u _{m0d of} the gas is adjusted in the manner described above, in a first step by quotient formation, the mean, modified residence time T _m0 d of the normal _tubes or, if initially a subgroup of normal _tubes is selected as reference _tubes , the

Reference standard pipes is determined. Subsequently, in a second step, the volume flow required for the same modified residence time ^~ u _m0 d is calculated. Finally, in a third step, the back pressure and the pressure drop for this

adapted volume flow by adding or removing the catalyst body to the catalyst bed.

If necessary, the reactor may after the

Filling are still subjected to an activation treatment, during which the catalyst is converted into the active form, for example by burned binder and possibly

Precursor compounds of components of the active composition,

For example, carbonates, hydroxides or nitrates are converted into the corresponding oxides.

As already explained, the active compounds, which of the catalyst bodies in the normal tube or in the thermal tube for

Not be the same. The active masses may have different active mass related

Activity constants 1st order A ^x _d have, from which then the required amounts of active material in by the

Reaction section S specific section of the pipe in question can be calculated.

In order to be able to change the catalyst activity, conventional measures can be taken, as already described above. Thus, the composition of the active composition can be changed so that the active materials in the normal pipe or thermal tube have a different composition. For example, promoters or moderators of the active composition can be added for this purpose. It is also possible, for example, the BET surface area or the pore volume of the

Active mass to change in this way different active mass-related activity constants 1st order A ^x _d for the To obtain catalysts used in the two groups of tubes. Possibly. For example, the catalyst bodies in a group of tubes can also be "diluted" by adding the bed

Inert bodies are added. According to a preferred embodiment, it is provided that the same active composition is used both in the normal tubes and in the thermal tubes. This makes it easier to map the temperature profile in the normal tube over a longer period of time in the thermal tube, so that, for example, even after a longer period of operation of the reactor more accurate information about the state of the normal tubes can be given. This is particularly advantageous because in this way too

Aging processes in the reactor can be tracked. When the active masses in the normal tube and thermal tube in their

Clearly different composition or their physical properties, this can cause the corresponding active materials age differently rapidly, so that a longer service life, a discrepancy between the temperature profile, as measured in the thermal tube, and the temperature profile of the normal tube occurs.

According to a preferred embodiment it is therefore provided that the activity of the catalyst body K _q by a

Adjustment of the amount of in the catalyst body K _q

set active mass is set. This can be achieved, for example, by the use of coated catalysts, the amount of active material contained in the shell of the shell catalyst is adjusted accordingly and, for example, the layer thickness of the shell is increased. In the case of unsupported catalysts, it is possible, for example, to proceed in such a way that one of the catalyst bodies, which are filled into the normal pipe or the thermal pipe, is correspondingly diluted with the aid of an inert filler material. According to another embodiment is in the way

proceeded that the activity of the catalyst body K _q is adjusted by adjusting the shape of the catalyst body K _q . In this embodiment, the catalyst body in the normal tubes in comparison to the catalyst bodies in the thermal tubes so a different geometry. In this way, on the one hand, the bulk density of the

Catalyst body and thus the amount introduced

Change active mass. On the other hand have smaller

Catalyst body on a higher geometric surface, so that a larger amount of active material on the

Apply catalyst body and at the same time higher bulk density is achieved.

An adaptation of the shape of the catalyst body K _q can

For example, take place in one of the tubes

For example, hollow cylinders are used which have a greater length or a larger outer or inner diameter

have as the catalyst body, which are used in the other tube. For example, according to one embodiment hollow tubular catalyst bodies can be used in one of the tubes, which have dimensions of 8 × 6 × 5 mm, while in the other group of tubes hollow cylinders with dimensions of 8 × 6 × 5, 7 × 7 × 4, 6 × 5 x 4 or 7 x 4 x 4 mm are used (outside diameter x length x inside diameter).

It is also possible to convert existing plants so that a reactor device according to the invention is obtained. In this embodiment, the reactor apparatus loaded with used catalyst bodies is first discharged, that is, the used catalyst bodies are first removed from the pipes of group G _p and the pipes of group G _q .

Subsequently, the reactor device is again with Loaded catalyst bodies, proceeding in the manner described above.

If the reactor apparatus for the production of

Phthalic anhydride used by gas phase oxidation of o-xylene and / or naphthalene, can be used according to a preferred embodiment in the manner described below.

When using the reactor device for the

Preparation of phthalic anhydride by gas phase oxidation of o-xylene and / or naphthalene is preferably used as a catalyst body, a shell catalyst. When

Carrier body are preferably used hollow cylinder of an inert material, on which a layer of the

Active material is applied. As the active material, conventional active materials for the gas phase oxidation of o-xylene or naphthalene to phthalic anhydride can be used. Preferably, an active composition is used, whose

Composition has already been described above.

In the coating of the carrier body with the active composition conventional methods are used. In this case, according to one embodiment, first a solution or suspension of the compounds used in the active material or their

Precursor compounds prepared. Precursor compounds are understood as meaning those compounds which, after, for example, calcination, can be converted into the corresponding catalytically active compounds, in particular the oxides. Such a suspension or solution is often referred to as mash. As the solvent, preferably water, but also organic solvents, such as

for example, alcohols are used. This mash can then be applied to the inert carrier body, for example, in a heated coating drum or in a fluidized bed. In particular, in an order of mash in a fluidized bed can the layer thickness with which the active composition is applied to the inert support body, are determined very accurately. The mash may optionally contain a binder so that the components of the active composition can be bound in a solid film on the inert support body. common

 Binders are, for example, organic polymers, such as

Copolymers of vinyl acetate / vinyl laurate, vinyl acetate / ethylene or styrene / acrylate, vinyl acetate / maleate and

Vinyl acetate / ethylene. The binder used is added in conventional amounts of the catalytically active composition, for example in a proportion of about 0.5 to 30 wt .-%, according to one embodiment in a proportion of 0.5 to 20 wt .-% based on the FestStoffgehalt of catalytically active mass. In addition to the binder, other common

Components may be included in the mash, for example pore formers. The with the components of the active mass

coated carrier body can then be filled into the corresponding tube of the reaction device. There, the binder can then be burned out during the activation of the catalyst. The adjustment of the pressure drop or the dynamic pressure then takes place in the manner described above.

Starting from the filling of the tubes from one group becomes a catalyst body for the filling of the other

Group of pipes, proceeding in the manner described above.

When using the reaction device for the

Preparation of phthalic anhydride by partial oxidation of o-xylene or naphthalene, according to one embodiment, uses bedstocks of catalyst bodies comprising multiple layers, the layers having a different catalyst activity.

According to a first embodiment, the

Catalyst arrangement three layers, wherein the Gaseintrittsseite layer has the lowest activity and towards the gas outlet side layer has the highest catalyst activity.

According to a further embodiment, the

Catalyst arrangement at least four layers, wherein the closest to the gas inlet side layer has a higher activity than the next, the gas outlet side layer lying. The subsequent layers in the flow direction then show, as already described above, a step-by-step increased activity with respect to the layer arranged upstream in the direction of flow.

The active composition of the catalyst bodies of the individual layers has a composition as already described above. The adaptation of the activity may be carried out by taking one or more of the following measures to control the activity of the shift in relation to the one in

Gas direction to increase previously arranged layer:

- a higher content of active material than in the

 Flow direction previously arranged layer;

 a higher BET surface area;

 - a higher vanadium content;

 - An increase in bulk density, for example by

 Use of other geometries of the catalyst body;

 the addition of activity-increasing promoters or the

 Increasing the proportion of the promoter in the active composition; or

- the absence or reduction of the amount

 activity-dampening moderators.

The measures can be taken individually or in combination

be realized. According to one embodiment, the active material of the

Catalyst body of the first catalyst layer between 5 and 25% by weight V ₂ 0 ₅ , 0 to 4% by weight Sb ₂ 0 ₃ , 0 to 1% by weight Cs, 0 to 3% by weight b ₂ 0 ₅ , 0 to 2% by weight The remainder of the active composition consists of at least 90% by weight, preferably at least 95% by weight, more preferably at least 98% by weight, especially preferably at least 99% by weight, more preferably at least 99.5% by weight. -% and in particular 100 wt .-% of T1O ₂ . In one embodiment, the BET surface area of the T1O _{2 is} between 15 and 45 m ² / g. Furthermore, it is preferred that such a first catalyst layer has a length fraction of 5 to 25%, particularly preferably 10 to 25%, of the total length of all the catalyst layers present, that is to say the total length of the catalyst bed present.

According to a further embodiment, the active composition in the second catalyst layer contains between 1 and 25% by weight of V2O ₅ , 0 to 4% by weight of Sb ₂ 0 ₃ , 0 to 1% by weight of Cs, 0 to 2% by weight. Nb ₂ 0 ₅ and 0 to 2 wt .-% P. The remainder of the active composition consists of T1O ₂ in the proportions described in the first catalyst layer. The BET surface area of the T1O ₂ is preferably between 15 and 25 m ² / g. The second catalyst layer comprises a length fraction of about 15 to 60%, preferably 20 to 60%, more preferably 20 to 50% of the total length of all existing

Catalyst layers.

According to a further embodiment, the active material of the catalyst of the third catalyst layer contains 1 to 25 wt .-% V ₂ 0 ₅ , 0 to 4 wt .-% Sb ₂ 0 ₃ , 0 to 1 wt .-% Cs, 0 to 2 wt. % Nb ₂ 0 ₅ and 0 to 2 wt% P. The remainder of the active composition consists essentially of T1O ₂ in the proportions given in the description of the first catalyst layer. This preferably has in the active composition of the third catalyst layer

used T1O ₂ a BET surface area between 15 and 35 m ² / g. Furthermore, the third catalyst layer preferably has a length fraction of about 20 to 50% of the total length of all existing catalyst layers. According to a further embodiment, four layers of catalyst bodies are provided in the tubes, wherein the activity provided by the catalyst layers preferably increases from the gas inlet side to the gas outlet side. The first catalyst layer closest to the

Gas inlet side, preferably, based on the weight of the catalyst body, an active material content of between 5 and 26 wt .-%, preferably between about 7 and 15 wt .-% to. The active composition preferably contains between 1 and 25 wt .-% V ₂ 0 ₅ , 0 to 4 wt .-% Sb ₂ 0 ₃ , 0 to 1 wt .-% Cs, 0 to 2 wt .-% Nb ₂ 0 _5f 0 to 2 wt .-% P and the rest to 100 wt .-% Ti0 ₂ . The second catalyst layer preferably contains one based on the weight of the catalyst body

Active composition content between 6 and 12 wt .-%, preferably between 6 and 11 wt .-%. The active material of this layer contains

preferably between 1 and 25 wt .-% V2O ₅ , 0 to 4 wt .-% Sb ₂ 0 ₃ , 0 to 1 wt .-% Cs, 0 to 2 wt .-% Nb ₂ 0 ₅ , 0 to 2 wt. % P and the remainder to 100% by weight of TiO ₂ . The third catalyst layer, based on the weight of the catalyst body, an active material content of 5 to 11 wt .-%, in particular 6 to 10 wt .-% have. The active composition of this layer preferably contains 1 and 25 wt .-% V ₂ Os, 0 to 4 wt .-% Sb ₂ C> 3, 0 to 1 wt .-% Cs, 0 to 2 wt .-% Nb ₂ 0 ₅ , 0 to 2 wt .-% of P and the balance to 100 wt .-% Ti0 ₂ .The fourth catalyst zone comprises, based on the weight of the catalyst body, has an active composition content of between about 7 and 25 wt .-%. The active composition of the fourth layer preferably contains 1 and 25 wt .-% V ₂ 0 ₅ , 0 to 4 wt .-% Sb ₂ 0 ₃ , 0 to 1 wt .-% Cs, 0 to 2 wt .-% Nb ₂ 0 ₅ , 0 to 2 wt .-% P and the remainder to 100 wt .-% Ti0 ₂ . According to a particularly preferred invention

Embodiment contains the active material of the catalyst of the first catalyst layer between 5 to 16 wt .-% V ₂ 0 ₅ , 0 to 5 wt .-% Sb ₂ 0 ₃ , 0.2 to 0.75 wt .-% Cs, 0 - 1 Wt% P and 0 to 3% by weight ₂ 0 ₅ . The remainder of the active composition consists of at least 90% by weight, preferably at least 95% by weight, more preferably at least 98% by weight, in particular at least 99% by weight, more preferably at least 99.5% by weight, in particular 100% by weight % of TiC> ₂ . According to a particularly preferred invention

Embodiment is the BET surface area of 1O ₂ between 15 and about 45 m ² / g. It is further preferred that such an upstream catalyst layer has a length fraction of 5 to 25%, particularly preferably 10 to 25% of the total length of all catalyst layers present (total length of the catalyst layer)

existing catalyst bed).

According to a particularly preferred invention

Embodiment contains the active material of the catalyst of the second catalyst layer between 5 to 15 wt .-% V2O ₅ , 0 to 5 wt .-% Sb ₂ 0 ₃ , 0.2 to 0.75 wt .-% Cs, 0 - 1 wt. -% P and 0 to 2 wt .-% Nb ₂ Ü ₅ . The remainder of the active composition consists of at least 90% by weight, preferably at least 95% by weight, more preferably at least 98% by weight, in particular at least 99% by weight, more preferably at least 99.5% by weight, in particular 100% Wt .-% of T1O ₂ . According to a particularly preferred invention

Embodiment is the BET surface area of T1O ₂ between 15 and about 25 m ² / g. Furthermore, it is preferred that such a second catalyst layer has a length fraction of about 15 to 60%, in particular 20 to 60% or 20 to 50% of the total length of all existing catalyst layers (total length of the existing catalyst bed).

According to a particularly preferred invention

Embodiment contains the active material of the catalyst of the third catalyst layer 5 to 15 wt .-% V ₂ 0 ₅ , 0 to 4 wt .-% Sb ₂ 0 ₃ , 0.05 to 0.5 wt .-% Cs, 0 - 1 wt % P and 0 to 2% by weight of Nb ₂ 0 ₅ . The remainder of the active composition consists of at least 90% by weight, preferably at least 95% by weight, more preferably

at least 98% by weight, in particular at least 99% by weight, further preferably at least 99.5% by weight, in particular 100% by weight, of 1 O 2. It is preferred that the T 1 O ^{2 has} a BET surface area between about 15 and 25 m ² / g. Continue

preferred that this third layer occupies a length proportion of about 10 to 30% of the total length of all existing catalyst layers, in particular if at least one further catalyst layer adjoins the third layer. Is it in the third layer to the last, so the

Reactor outlet closest location, so is a

Length fraction for the third layer of 20-50% preferred.

According to a particularly preferred invention

Embodiment contains the active material of the catalyst of the fourth catalyst layer 5 to 25 wt .-% V ₂ O ₅ , 0 to 5 wt .-% Sb ₂ 0 ₃ , 0 to 0.2 wt .-% Cs, 0 - 2 wt. % P and 0 to 1 wt .-% b ₂ Ü ₅ . The remainder of the active composition consists of at least 90% by weight, preferably at least 95% by weight, more preferably at least 98% by weight, in particular at least 99% by weight, more preferably at least 99.5% by weight, in particular 100% by weight from ί θ2. Insofar as the fourth layer represents the (last) catalyst layer located at the gas outlet side of the reactor, a BET surface area of T 1 O 2 is preferred which is slightly higher than that which lies closer to the gas inlet side

Layers, in particular in the range between about 15 to about 45 m ² / g. Furthermore, it is preferred that such a fourth catalyst layer occupies a length fraction of about 10 to 50%, particularly preferably 10 to 40% of the total length of all existing catalyst layers. A fifth

Catalyst layer is then usually not required, but especially for longer reactor tubes possible. Furthermore, the invention relates to a process for the preparation of at least one product, wherein at least one gaseous educt is fed to a reactor apparatus as described above. The at least one gaseous educt is converted to a catalyst product K _m , K _n , which are provided in the first and second groups G _m , G _n of tubes, wherein the reaction conditions for the reaction of the at least one reactant to the at least one product are so selected in that a specific temperature or a specific temperature gradient is set in the thermo tubes of the second group G _n of tubes.

The reactor device described above is suitable for a variety of reactions, which by a solid

Catalyzed catalyst. Since the temperature or the temperature profile in the normal pipes very well in the

Thermo tubes can be displayed, the temperature profile or a temperature at a specific point of the

Thermo tube can be used to adjust the conditions in the normal tubes with high accuracy, ie

For example, the influx of at least one reactant, the control of the heat transfer medium through the pipes

supplied or removed from this amount of heat or the addition of moderators to the reaction gas stream. Furthermore, the aging of the catalyst or more accurately the active mass can be observed, so that with a deterioration of the

Turnover, the reaction conditions can be tracked, with a new temperature profile is set in the thermal tubes and thus in the normal tubes.

The reaction conditions are chosen in a conventional manner for the reaction in question, but the

Control of the reaction, so for example, the readjustment of the reactor in an aging of the active composition, over the

Temperature profile of the thermal tubes takes place.

According to a preferred embodiment, the

Reactor device according to the invention for the production of phthalic anhydride by partial oxidation of o-xylene

and / or naphthalene used in the gas phase. It will Generally, a gaseous stream containing o-xylene and / or naphthalene and molecular oxygen, at elevated temperature, in particular between about 250 and 490 ° C, passed through the normal tubes or thermotubes. In the tubes, several layers of catalyst bodies are preferably arranged, in particular three or four layers, wherein the catalyst activity of the different layers is preferably chosen differently, in particular preferably

Catalyst activity in the flow direction of the gas stream from the first gas inlet side layer to the next initially decreases to then increase again from layer to layer.

The loading of the gas stream with o-xylene or naphthalene is preferably selected in a range of 40 to 100 g / Nm ³ air. The back pressure in the tubes is preferably a bar in the range 1 to 5 _{para o} iut, - preferably 1 to 2 bar _abs chosen _o iut.

The pressure drop over that provided in the tubes

Catalyst bed is preferably in the range of 80 to 600 mbar.

According to a further embodiment, the reactor device according to the invention is used for the production of maleic anhydride. The educt used is preferably benzene or butane. In one embodiment, the reactor apparatus may be used to convert vinyl acetate monomers

To produce gas phase oxidation of ethylene in the presence of acetic acid.

Furthermore, the reactor apparatus for the production of

Ethylene oxide can be used by partial oxidation of ethylene. According to a further embodiment, with the

Reactor device according to the invention also acrolein or

Acrylic acid can be prepared by partial oxidation of propene.

The reactor device is also suitable for the production of methacrolein and methacrylic acid by gas-phase oxidation of isobutene.

According to another embodiment, the

Reactor device for the production of formaldehyde by

Gas phase oxidation of methanol can be used.

The invention will be further illustrated by way of examples and with reference to the accompanying drawings. Showing:

1 shows a curve in which the mass-related activity constant A ^{* of} the active composition determined at certain GHSV ^'s and a specific temperature is plotted against the o-xylene conversion.

For the determination of the parameters of the catalyst were used with the following methods:

BET surface area

The determination of the specific BET surface area and the

Mesopores are made according to the BJH method according to DIN 66134.

Pore radius distribution / pore volume

The pore radius distribution and the pore volume were determined by mercury porosimetry according to DIN 66133;

maximum pressure: 2000 bar, Porosimeter 4000 (Porotec, DE), according to the manufacturer's instructions. Great particle

The particle sizes were determined by laser diffraction using a Fritsch Particle Sizer Analysette 22 Economy (Fritsch, DE) according to the manufacturer's instructions. to

Sample preparation is carried out in deionized water without addition of auxiliaries 5 minutes by treatment with the sample

Ultrasound homogenized.

The BET surface area, the pore radius distribution or the pore volume and the particle size distribution were determined in the characterization of the titanium dioxide in each case at a uncalcined at 150 ° C in a vacuum dried

Material.

The proportion of active mass (proportion of the catalytically active composition, without binder) relates in each case to the proportion (wt .-%) of the catalytically active composition in the total weight of the

 Catalyst body, including carrier body in the

respective catalyst layer, measured after conditioning for 4 hours at 400 ° C in air.

A) Determination of the Active Mass-Related Activity Constant of First Order a) Test Reactor

For the determination of the active mass-related activity constants 1 st order A ^{1 of} the catalyst, a reaction tube with a length of 120 cm and an inner diameter of 24, 8 mm is used. Inside the reaction tube is for the

 Temperature measurement along the longitudinal axis of an inner tube

arranged, which has an outer diameter of 3 mm. In the inner tube, a temperature sensor is arranged, which can be moved along the longitudinal axis, so that over the entire length of the reaction tube, a temperature profile

can be included. The reaction tube can via a Length of 100 cm to be tempered with a heat transfer medium.

At the upper end of the reaction tube can over a

Mass flow controller a defined air flow in the

Reaction tube to be fed. The air stream first passes through a thermostated mixing chamber, in which a defined amount of o-xylene can be injected into the air stream and mixed with it. The pressure drop is monitored by each arranged at the beginning and at the end of the reaction tube pressure gauge.

In the reaction tube, a catalyst bed diluted with inert bodies is introduced, which has a length of 80 cm. The catalyst bed is placed in the isothermal region of the reaction tube. b) Preparation of the catalyst body

For the preparation of the catalyst body 2000 g

Hollow cylinder made of steatite with the dimensions 8 x 6 x 5 mm (outer diameter x length x inner diameter) used. These support bodies are coated in a fluidized bed coater at 70 ° C. with a mash of the active composition. To prepare the mash, 17 g of vanadium pentoxide, 7.03 g of antimony trioxide, 1.14 g of cesium sulfate, 1.7 g

Ammonium dihydrogen phosphate, 195.0 g of titanium oxide having a BET surface area of 21 m ² / g, and 130.5 g of binder (50% dispersion of vinyl acetate / ethylene copolymer in water

(Vinnapas ^® EP 65 W, Airflex, DE)) was suspended.

The catalyst had an active composition content of 8% by weight, the active composition having a composition of 7.5% by weight.

Vanadium pentoxide, 3.2% by weight antimony trioxide, 0.40% by weight

Cesium (calculated as cesium), 0.2% by weight of phosphorus and the remainder to 100% by weight of titanium oxide. c) Charging the test reactor

The catalyst bodies are diluted in a mass ratio of 17: 1 (w / w) with steatite inert bodies. Hollow cylinders with the dimensions 5 × 5 × 2.5 mm are used as inert bodies. The catalyst bodies and the inert bodies are individually in the

Interior of the reaction tube, so that a uniform distribution of catalyst bodies and inert bodies in the

Reaction space of the reaction tube is achieved. d) activation of the catalysts For activation, the air flow to 400 Nl / h and the

 Heat transfer medium set to a temperature of 420 ° C. The catalyst is then calcined for 60 hours. To the

Calcination followed by an equilibration of the

Catalyst at a temperature of 420 ° C and a

Gas composition of 60 g / Nm ³ o-xylene (purity 99.9%) and 400 Nl / h of air for 48 hours. e) Carrying out the measurement

To determine the performance data will be after the

Aquilibrierung 60 g / Nm ³ h o-xylene at a maximum of 0.5 Nl / h air passed over the catalyst, with one on the

Catalyst mass-related space-time velocity of 5 1 / hxm _kat (GHSVi), 10 1 / hxm _kat (GHSV ₂ ), or 15 1 / hxm _kat (GHSV ₃ ) is set. The heat carrier temperature is set in each case so that an average catalyst temperature of 420 ° C is reached. After setting new

Reaction conditions, the reactor is equilibrated for one hour. The reaction gas is analyzed after its exit from the reaction tube to its constituents and the o-xylene Umsat z determined at 420 ° C average catalyst temperature. From the measured o-xylene sales then the

mass-related activity constant A ^* 1st order of the active composition at 420 ° C calculated according to the formula already explained above.

\ j ⁿ -Active mass \

The amount of active material m _Akt i _vmasse was 1.5 g. The o-xylene conversion z is calculated according to

^ ⁰ ^ o-xylene (pure) ^~ ^ ° ^ o-xylene (out)

The determined sales and mass related

Activity constants of 1st order A ^{* of} the active composition at 420 ° C. are summarized in Table 1 together with the reaction conditions. Table 1: Values for determining the mass-related

Activity constants A ^* 1st order of the active mass (T = 420 ° C!

In FIG. 1, the mass-related activity constant is 1.

Order A ^{* of} the active composition is plotted against the o-xylene conversion z. This results in an active-mass-related activity constant A ¹ of 479 [l / h * g] for an o-xylene conversion z of 85%. B) Testing the temperature profiles of a reactor device according to the invention a) test reactor

To carry out the experiments, a system is used, which is provided with a receptacle for tubes with a diameter of 20 to 30 mm. 4 m long pipes can be inserted into the receptacle, while a distance of 3.50 m can be thermostated with a salt bath. As normal pipes tubes with an inner diameter of 25 mm or 21 mm are used. To the temperature profile in the

 Normal tubes to be determined, are arranged in the normal tubes along the longitudinal axis of temperature probes fixed at a certain distance. The space requirement of this

Temperature probes is minimal. For the implementation of

Examples are therefore assumed for the normal tubes, the outer diameter of the temperature probe (inner tube) as "0".

Thermo tubes are tubes with an inner diameter of 21, 25, 27 or 29 mm, which are provided with an inner tube with an outer diameter of 3, 8 or 10 mm. In the inner tube in each case a displaceable in the longitudinal direction of the inner tube temperature probe is arranged. The dimensions of the tubes used are shown in Table 2.

At the top of the tubes is a gas inlet, via which a constant flow of gas can be conducted into the tubes by means of a mass flow controller. The gas flow happens before

Entry into the reactor a mixing section, in which o-xylene can be metered. b) Preparation of the catalyst body for normal pipes

Analogous to the production of the above-described

Catalyst body for determining the active-mass-related

Activity constant 1st order A ¹ become test bodies with one Active mass content of 8 wt .-% (normal tube with 25 mm inner diameter) produced. As a carrier body

also used steatite hollow cylinder. The dimensions of

Carrier body and the active material content of the catalyst body are shown in Table 2. c) Preparation of the catalyst body for thermal tubes

On the basis of the bulk densities and thus obtained quotients of active mass per tube wall surface for normal and the o.g. Thermal tube geometries were produced catalyst body for the thermal tubes. In this case, the active composition contents stated in Table 2 were determined for the support bodies. d) Charging the test reactor

The standard and thermal tubes of the test reactor are filled with the catalyst bodies indicated in Table 2. The

Adjustment of the modified residence time T _m0d is carried out as described above on the calculation of the for a comparable mod. _Residence time T _m0d required volume flow by means of

Pressure drop on the thermal tube, the selection of the geometry of the catalyst body and the length of the bed. If the pressure drop is too high, the bed will be shortened, if it is too low

Pressure reduction is the correction by presenting

Inert (5 x 5 x 2.5, A x L x I) or through quartz sand. The bed lengths and the pressure drop of the pipe in question are also given in Table 2. Table 2: Parameters of the test reactor

di/d_a (mm) Innendurchmesser des Außenrohrs /

di / d _a (mm) Inner diameter of the outer tube /

 Outer diameter of the inner tube

 Carrier (mm) Dimensions of the hollow cylinder

 (Outer diameter x length x

 Inside diameter)

 Aktivm./ Body Active mass content based on the weight (wt.%) Of the catalyst body

 Aktivm / Area Active mass content per tube wall surface

(g / cm ² )

Pressure loss, (mbar; pressure loss at 3000 cm bed length, linear gas velocity 4 Nm ³ / h, RT

Bed bed length of the catalyst body in the

 pipe

 with 5 to 20 mm sand at the gas outlet

e) comparative temperature measurement

For the temperature measurement, an air flow is passed from top to bottom through the thermal or the normal pipe, wherein the air flow is set to a flow rate of 4 Nm ³ / h. The air flow is loaded with 30 to 100 g / Nm ³ o-xylene

 (Purity o-xylene:> 99%). The total pressure is approx.

 1450 mbar. The temperature of the salt bath will be up to 352

356 ° C set. The test results are summarized in Table 3. f) Comparative Example

For comparison, an adjustment of the active material content in normal pipe and thermal tube is carried out analogously to the method as described in EP 0 873 783 A. However, since in the present case not solid but shell catalysts are used, the pressure drop is due to a layer of sand

set, which connects to the gas outlet on the bed of the catalyst body.

In the comparative example, the ratio of the amount of active composition to the free cross-sectional area for normal and

 Thermo tube set to the same value. So it is for the adaptation of thermal and normal pipe exclusively the

Residence time x, defined as the quotient of reactor volume and volume flow, and not the modified residence time T _m0d

used.

For the example, steatite hollow cylinders of dimensions 8 × 6 × 5 mm are used for the normal tube, which have an active mass content of 8%, based on the weight of the catalyst body. Become for the thermal tube

Steatite hollow cylinder with the dimensions 8 x 6 x 5 mm

used, which have an active mass content of 8%, based on the weight of the catalyst body.

Normal pipe:

The standard pipe had a ratio of the amount of active mass to the free pipe cross-sectional area of 1227 g of catalyst: 491 mm ² = 2.50. The pressure drop in the test reactor was determined at a gas flow rate of 4 Nm ³ / h to 99 mbar, which is a

modified residence time ^~ u _m0d of 0.37 g / s. Thermotube (comparative experiment):

At approximately the same filling level of the catalyst bed, the thermal tube has a ratio of the amount of active composition to free cross-sectional area of 1552 g of catalyst: 582 mm ² = 2.67, wherein measured at a gas flow rate of 4 Nm ³ / h, a pressure drop in the test reactor of 91 mbar becomes. This corresponds to a modified residence time ^~ u _m0d of 0.46 g / s.

To the ratio of amount of active mass to free

 To adjust the tube cross-sectional area to the value of the standard tube of 2.50, now the thermal tube with only 1455 g

Catalyst fed. At a mass flow of 4 Nm ³ / h, a pressure drop in the test reactor of 87 mbar is then measured. In order to adjust the pressure drop to 99 mbar as in the normal _pipe, sand is introduced onto the gas outlet side of the catalyst _bed , resulting in a modified residence time T _m0 d of 0.52 g / s.

The values measured with the comparison arrangement are

 also summarized in Table 3.

Table 3: Test results

 Δρ: pressure drop

T _h . _see : Temperature hot spot

Adj. Ap ^a : adaptation pressure drop

 Gene. T-measure .: Accuracy of temperature measurement

a: by presenting sand g) check the equation for setting the

 Catalyst activity (erf .gem example)

In order to check the equation, the examples according to the invention described above are described below

Calculations performed as an example.

wobei bedeutet: The equation is

where:

A _N : the catalyst activity in which by the

 Reaction distance S certain volume section

 Standard pipe is provided,

A _T : the catalyst activity in which by the

 Reaction section specific volume section is provided in the thermal tube,

W _N : the inner surface of the normal tube, which through the

 Reaction distance S is determined

W _T : the inner surface of the thermal tube passing through the

 Reaction distance S is determined, a: the correction factor.

The activity A _{NfT is} calculated to

Α _Ν , τ = ¹ · M _N , _T where

A ¹ : the active mass-related activity constant 1.

Order of the active mass, M _NfT : the amount of the provided by the catalyst _bodies in the defined by the reaction section S volume portion of the normal or thermal tube

 Active mass.

As stated above, the active mass related

Activity constant 1st order of the active composition A ¹ to 480 [l / h * g] determined.

Determination of the correction factor a

The data for checking the equation are summarized in Table 4 again.

Table 4: Data for the verification of the invention

 example

This gives a to 0, 99

Claims

 claims Reactor device with at least a first group G _m of pipes, which comprises at least one normal pipe, which is filled with catalyst bodies K _m , and a second group G _n of pipes, at least one with a Temperature measuring device provided thermal tube comprises, which is filled with catalyst bodies K _n , wherein the catalyst body K _m , K _n each in a in Are arranged longitudinally of the tubes along a reaction section S extending volume portion, characterized in that

where: A _m : a catalyst activity in which by the Reaction section S certain volume section in the tube from the first group G _{m is} provided A _n : a catalyst activity in which by the Reaction distance determined volume section in the tube from the second group G _{n is} provided, W _m : an inner surface of the tube from the first group G _m , which is determined by the reaction path S, W _n : an inner surface of the tube of the second group G _n , which is determined by the reaction distance S, a: a correction factor, which is selected in the range of 0.8 to 1.2, wherein the catalyst activity A _b calculated according to A _b = A ^■ M _b where: A ^x _b : an active mass related activity constant 1. Order one of the catalyst body K _b  provided active mass, M _b : the mass of the catalyst bodies K _b in the defined by the reaction path S.  Volume section of the pipe provided Active mass, b: an index which is selected from n and m and the catalyst body K _b in the by the  Said reaction section S defined volume portion of the tube. Reactor device according to claim 1, characterized in that the tubes of the first and the second group G _m , G _n modify the substantially same pressure drop and / or the substantially same modified one _Dwell time have T _m0 d. Reactor device according to claim 1 or 2, characterized in that the temperature measuring device is designed as a tube arranged along the longitudinal axis of the thermal tube, in which at least one temperature sensor is arranged. Reactor device according to one of the preceding Claims, characterized in that the Catalyst body K _m , K _n in the volume section defined by the reaction section S form a homogeneous bed. Reactor device according to one of the preceding Claims, characterized in that the Catalyst body K _m and the catalyst body K _n in the each having a homogeneous shape defined by the reaction section S volume portion. Reactor device according to one of the preceding Claims, wherein the active mass in the tubes of the group G _m and the tubes of the group G _n an equal Composition and further comprises: Mm ₌ (n M _n ^a Wn) where: M _m : the mass of the active mass in which by the Reaction section S certain volume section in the tube from the first group G _{m is} provided M _n : the mass of the active mass in which by the Reaction section S certain volume section is provided in the tube from the second group G _n , W _m : an inner surface of the tube from the first group G _m , which is determined by the reaction path S, W _n : an inner surface of the tube of the second group G _n , which is determined by the reaction distance S, a: a correction factor, which is selected in the range of 0.8 to 1.2. Reactor device according to one of the preceding Claims, characterized in that the Catalyst body K _m and the catalyst body K _{n are formed} as supported catalysts with a layer of the active composition. Reactor device according to claim 7, characterized in that the active mass of the catalyst bodies K _m , K _n has the same composition and activity A _{b is} determined by the layer thickness of the applied on the supported catalyst active material. 9. Reactor device according to one of the preceding  Claims, characterized in that the Catalyst body K _m , K _{n have} a different geometry. 10. Reactor device according to one of the preceding Claims, characterized in that in the tubes of the first group G _m and in the tubes of the second group G _n more than one reaction path S is provided, wherein the Reaction sections S each volume sections in the  Define tubes, and in the volume sections different catalyst body K _m , K _n are arranged. 11. Reactor device according to one of the preceding  Claims, wherein a layer of inert bodies for  Adjustment of pressure drop and linear  Gas velocity is provided. 12. A method for providing a reactor apparatus according to one of the claims 1 to 11, comprising at least a first group G _m of pipes comprising at least a normal pipe, and a second group G _n of pipes, which at least one with a temperature measuring device provided in a group G _p of pipes, which is selected from the first group G _m or the second group G _n of pipes, catalyst body K _{p are} filled, so that at least one determined by a reaction section S volume of the pipe with the Catalyst bodies K _{p is} filled, in which determined by the reaction path S. Volume section of the pipe from the group G _p a Catalyst activity A _{p is} determined to be filled in a group G _q of pipes that do not belong to the group G _p catalyst body K _q , wherein the catalyst body K _{q have} an activity that in a determined by the reaction path S. Volume section of the tube from the group G _q a Catalyst activity A _{q is} obtained, where:

where: A _p : a catalyst activity in which by the Reaction distance S certain volume section is provided in a pipe from the group G _p , A _q : a catalyst activity in which by the Reaction section S certain volume section is provided in a tube from the group G _q , W _p : an inner surface of the pipe from the group G _p , the  is determined by the volume section determined by the reaction path S, W _q : an inner surface of the tube from the group G _q , the is determined by the volume section determined by the reaction section S, a: a correction factor selected in the range from 0.8 to 1.2, the catalyst activity A _{d being} calculated according to A _d = A ^ · M _d where: A ¹ _d : an active mass-related activity constant 1. Order one of the catalyst body K _d provided active mass, M _d : the mass of the catalyst bodies K _d in the  defined by the reaction path S. Active mass provided by the volumetric section of the tube, d: an index selected from p and q and the catalyst body K _d in the active mass  Said reaction section S defined volume portion of the tube. 13. The method according to claim 12, wherein a in the tubes of the group G _p and a generated in the tubes of the group G _q pressure drop and / or a modified residence time T _{mod is set} to a substantially same value. 14. The method of claim 12 or 13, wherein the activity of the catalyst body K _q by adjusting the amount of provided in the catalyst body K _q  Active mass is adjusted. 15. The method according to any one of claims 12 to 14, wherein the activity of the catalyst body K _q is adjusted by adjusting the shape of the catalyst body K _q . 16. The method according to any one of claims 12 to 15, wherein the reactor device is loaded with used catalyst bodies and the used catalyst body are first removed from the pipes of the group G _p and the pipes of the group G _q . 17. A process for producing at least one product, wherein at least one gaseous educt of a reactor device is fed to one of the claims 1 to 11, the at least one gaseous reactant to in the first and the second group G _m , G _{n provided} by tubes catalyst bodies K _m , K _{n is converted} to a product, wherein the reaction conditions for the implementation of at least one reactant to the at least one product are selected so that in the thermal tubes of the second group G _n of tubes a certain temperature or a  certain temperature gradient is set. 18. The method of claim 17, wherein the starting material is selected from the group of o-xylene and naphthalene and the product is phthalic anhydride.