CN103923047A - Method for optimizing the active material load of phthalic anhydride catalyst - Google Patents

Abstract

The present invention relates to a method of providing a reactor system, and the reactor system is used for the production of phthalic anhydride through vapor-phase oxidation of aromatic hydrocarbons at at least one catalyst made of a vanadium-containing material, wherein the active material load is optimized by means of a model.

Description

Optimize the method for the active material load of Tetra hydro Phthalic anhydride catalyzer

Technical field

The present invention relates to a kind of method that reactor assembly is provided, this reactor assembly is prepared Tetra hydro Phthalic anhydride for gaseous oxidation aromatic hydrocarbons at least one catalyzer by by making containing vanadium active material.

Background technology

Carry out the technical grade of Tetra hydro Phthalic anhydride produces by the catalytic vapor phase oxidation of o-Xylol and/or naphthalene.For this purpose, in reactor, provide the catalyzer that is suitable for this reaction, be generally containing vanadium contact, and reaction gas is passed through above catalyzer.Preferably, so-called multi-tubular reactor is used as to reactor, the large buret that is wherein arranged in parallel, refrigerant flows around pipe.In general, salt-melting is used as to refrigerant, for example NaNO ₂and KNO ₃eutectic mixture.

Catalyzer is packed in pipe with catalyst body form.Under simple scenario, use homogeneous bed of packings.The reaction gas that makes subsequently to contain the mixture of oxygen-containing gas (being generally air) and hydrocarbon (being generally o-Xylol or naphthalene) to be oxidized passes through above bed of packings.

The oxidation heat liberation of hydrocarbon is strong, and result is special in the region of reactor inlet, observes heat-flash and generates.For the high productivity of realization response device, use structural catalyst bed of packings as a transition, wherein the catalyst layer of different activities is arranged in one deck in pipe on another layer.

At present, conventionally use 3 layers of catalyst filling bed, wherein, on reactor inlet limit, arrange and there is relatively SA catalyst layer, progressively increase active catalyst layer immediately following having thereafter.Therefore will there is the most highly active catalyst layer and be arranged in reactor outlet side.This system is for example known from EP1 082 317B1, EP1 084115B1 or WO2004/103944 (A1).

Recently, use and there is four layers or more multi-layered catalyst system as a transition, wherein first the relative thin layer of greater activity catalyzer is arranged in to reactor inlet side.To be attached to this greater activity layer compared with low activity layer, should be other layer that catalyst activity further increases compared with low activity layer subsequently.This catalyst system is for example known in WO2007/134849A1 or WO2011/032658.

Between the oxidation period of o-Xylol or naphthalene, except valuable product Tetra hydro Phthalic anhydride, a series of unwanted secondary species are also formed as carbon monoxide, carbonic acid gas, phenylformic acid, maleic anhydride or citraconic anhydride.In addition, valuable product also may be polluted by the compound forming due to the incomplete conversion of educt.The example of this intermediate product is o-toluylaldehyde and phthalide.It is high as much as possible to the selectivity of Tetra hydro Phthalic anhydride oxidation that required is, and in final product, the ratio of secondary species or intermediate product may be minimum, and initial product has high conversion simultaneously.

At present, realized mole selectivity of the Tetra hydro Phthalic anhydride up to 81 % by mole.In order further to increase the selectivity of o-Xylol or naphthalene oxidation to phthalic anhydride, can change the different parameters of catalyst system.Therefore, the composition of catalyzer can change, or the character of catalyst filling bed also can change.For this point, for example, can change arrangement and the length of indivedual catalyst layers.

But the empirical improvement of catalyzer or catalyst filling bed relates to high experimental expenses.This is especially correct for the multilayer system that wherein indivedual layers of system must be optimized and match each other.Even if the cost plenty of time, may only obtain indivedual parameters describing very roughly whole system impact.

Summary of the invention

Therefore, object of the present invention is for providing a kind of method that reactor assembly is provided, this reactor assembly is for preparing Tetra hydro Phthalic anhydride by contain gaseous oxidation aromatic hydrocarbons on vanadium active material at least one, and the method implements very simple and makes this reactor assembly of rapid Optimum become possibility.

The method of feature of requirement 1 of having the right this purpose apparatus realizes.The preferred embodiment of the method is the theme of dependent claims.

In the method according to the invention, use a kind of model, it makes to draw the layer L about catalyzer phase _mactive material load M _m,nor layer L _mmiddle catalyst A _m,nthe active material load M providing _m,nthe conclusion of the impact of change on performance perameter, for example, according to the thermal equilibrium of catalyzer and gas phase, in the material balance being issued to for the various situations of gas phase and catalyzer phase and consider material transferring in catalyst body and for prepare the reaction kinetics of Tetra hydro Phthalic anhydride, the reaction preference aspect Tetra hydro Phthalic anhydride by the gaseous oxidation of aromatic hydrocarbons.Use this model, catalyst layer L _mactive material load M _m,ncan systematic change and the impact of systematicness record on a performance perameter.In this way, the layer L of catalyzer phase _mactive material load M _m,nor by layer L _mmiddle catalyst A _m,nthe active material load M providing _m,ncan be optimised about performance perameter.The catalyzer phase definite with this model can be provided subsequently in reactor, and the reactor assembly of therefore optimizing is available, and the reactor assembly of this optimization for example has improved selectivity aspect Tetra hydro Phthalic anhydride.

Therefore the present invention is directed to a kind of method that reactor assembly is provided, and this reactor assembly is for passing through at least one catalyst A _m,nupper gaseous oxidation aromatic hydrocarbons is prepared Tetra hydro Phthalic anhydride, and reactor assembly comprises the catalyst body containing containing vanadium active material, wherein:

-multi-tubular reactor is provided,

-thering is the pipe that quantity is b, this pipe has

-diameter D, and

-length of tube L;

Wherein pipe has the tube wall of specific tube wall thickness, and refrigerant flows around tube wall, and refrigerant has average coolant temperature T _k;

-in pipe, provide to comprise at least one layer of L _mcatalyzer phase, its middle level L _mcomprise catalyst A _m,n, wherein m be assumed to be 1 and the maximum number of plies between round values and n be represent special catalyst from 1 to n subscript, and by catalyst A _m,nat layer L _min active material load M is provided _m,n; With

-formation gas phase and the reaction gas that contains at least one reactive component pass through pipe;

-be the gas phase of pipe and the multi-tubular reactor of catalyzer phase for multi-tubular reactor, a kind of model is provided, this model description

-thermal equilibrium, and,

-in the various situations for gas phase and catalyzer phase, material balance, and

-material transferring in catalyst body, and

-for prepare the reaction kinetics of Tetra hydro Phthalic anhydride by the gaseous oxidation of aromatic hydrocarbons;

-set up the operational condition of multi-tubular reactor by setting at least following content

The specific throughput of reaction gas of-every pipe;

In-reaction gas the certain concentration of at least one reactive component and

The specific average coolant temperature T of-described refrigerant _k;

-determine performance characteristic, it can the value of being assumed to be W _n;

-use described model, by following definite difference DELTA

A) to limit D-value Δ _gdistribute a value;

B) there is the first catalyst A _{m, 1}layer L _min the first active material load M is provided _{m, 1}and, under the operational condition of multi-tubular reactor, determine the first value W of performance characteristic ₁;

C) pass through at layer L _min via the second catalyst A _{m, 2}the second active active material load M is provided _{m, 2}, change layer L _mactive material load;

D) under the operational condition of multi-tubular reactor, use for the second catalyst A _{m, 2}model determine the second value W of performance characteristic ₂;

E) compare the first value W ₁with the second value W ₂and definite difference DELTA;

With use catalyst A _m,nrepeating step b to e until difference DELTA drop on lower than limit D-value Δ _gamount in;

-provide by limit D-value Δ _gdefinite catalyst A _m,G, and

-in the pipe of reactor, provide by catalyst A _m,Gat least one layer of L of the catalyzer phase forming _m.

Embodiment

In the method according to the invention, first provide multi-tubular reactor.Can use such as the known conventional multi-tubular reactor for the preparation of Tetra hydro Phthalic anhydride.This multi-tubular reactor comprises for example 20,000 pipes of as many as, and these pipes are arranged in parallel with each other in refrigerant space, and refrigerant can flow by described pipe.Also likely carry out for comprising the only method of the reactor of single pipe.For industrial scale applications, the quantity b of pipe is chosen as many as 50,000, according to an embodiment as many as 15,000.According to an embodiment, the quantity of pipe is selected to be greater than 1,000.

Pipe has diameter D, wherein refers to the internal diameter of pipe herein.Preferably, the diameter D of pipe is chosen as in 10 to 50mm scope, and more preferably 20 to 40mm.Pipe has the length of tube L being chosen in equally in normal ranges.This length of tube is corresponding to the length of the pipe of filling mutually with catalyzer.In the time of definite length of tube L, do not consider by for setting pressure, for preheating reaction gas or for setting the part of inert material pipe that fill or empty of fill level.If arrange some pipes in a reactor, use in all cases the arithmetical av of pipe diameter and length of tube.Length of tube L is preferably chosen in 1 to 10m scope, more preferably in 2 to 5m scope.

Conventionally, the diameter D of the number of parameters b of pipe, pipe and length of tube L are by using catalyst A _m,n, for example, as the surrogate of spent catalyst, the already present reactor of filling pre-determines.

In refrigerant space, inner tube is arranged one by one with conventional distance.Horizontal throw between two pipes can be for example 1 to 5cm, is 2 to 4cm according to an embodiment.Can in refrigerant space, provide conventional interior arrangement, for example deflecting plate, to ensure that therefore effectively fully mixing of refrigerant also ensure effective heat dissipation.

This pipe has tube wall, and described tube wall separates catalyst filling bed or the catalyzer phase in implication of the present invention with the refrigerant that surrounds this pipe, and heat transmission occurs to remove the heat forming between the oxidation period of aromatic hydrocarbons via this pipe.Pipe is obtained as steel by conventional material, and has specific tube wall thickness, and described thickness of pipe is chosen within the scope of the conventional wall thickness for this pipe, and for example 1 to 5mm.Via the wall of this pipe, be arranged in the catalyzer phase of this pipe inside or gas phase and around may heat exchange between the mobile refrigerant of this pipe.Use conventional refrigerant as refrigerant, for example salt-melting, the NaNO for example, having mentioned in introducing ₂and KNO ₃eutectic.Refrigerant has average coolant temperature T _k.In the method according to the invention, also use the space analysis temperature profile of refrigerant itself.But this will significantly increase the expense of carrying out the method.The temperature that represents coolant temperature is used as to average coolant temperature T _k.It can be by being determined by the one or more measurement point calculating mean values that are suitably arranged in the refrigerant space of reactor.For example can be when measuring in the refrigerant space of reactor that refrigerant supply and refrigerant remove the temperature of refrigerant, and calculate thus arithmetical mean, determine average coolant temperature T _k.But, some measurement point are also likely provided in reactor, measure in order the temperature of refrigerant in described measurement point, for example calculate arithmetical mean by these values subsequently.

Catalyzer phase is provided subsequently in pipe.By catalyst A _m,nat least one layer of L _mform catalyzer phase.Layer L _mhave by catalyst A _m,nthe active material load M providing _m,n.

Under simple scenario, catalyzer is by catalyst A _{1, n}simple layer L ₁form.

According to an embodiment, catalyzer comprises catalyst A mutually _m,nat least two layer L _m.But catalyzer is mutually preferably by several layer of L _m, preferred at least three layer L _mform, according to another embodiment, by least four layer L _mform.According to an embodiment, catalyzer comprises mutually and is less than six layer L _m, according to another embodiment, be less than five layer L _m.

According to an embodiment, catalyzer is mutually definitely by three layer L _mform, according to another embodiment, definitely by four layer L _mform.Subscript m be correspondingly assumed to be 1 and layer maximum quantity between round values.If catalyzer comprises three layers mutually, correspondingly value of being made as 1,2 and 3 of subscript m, wherein each value representation catalyzer one deck in mutually.If catalyzer comprises four layers mutually, subscript m is the value of being made as 1,2,3 and 4 correspondingly.Catalyst A _m,ncharacter in one deck, be preferably homogeneous, that is, and catalyst A _m,nhave for example homogeneous bed of packings and constant composition, result is at a layer L _min, catalyst A _m,nhomogeneous activity in routine techniques fluctuation is provided.

Each layer of L _m,nin all cases by catalyst A _m,nform, wherein m can be assumed to be value defined above and n represents subscript, and it can be assumed to be 1 to n value and represent to be arranged in all cases a layer L _min special catalyst.Pass through catalyst A _m,nactive material load M is provided in layer _m,n.

Catalyst A _m,ncomprise the catalyst body containing containing vanadium active material.According to an embodiment, form catalyst A by the bed of packings of catalyst body _m,n.Pipe inner tube longitudinally on there is the catalyst body of specific extension bed of packings form the layer L in implication of the present invention _m.At least one layer of L _m, according to an embodiment, several layer of L _mform subsequently the catalyzer phase in implication of the present invention.

Comprise mutually several layer of L at catalyzer _msituation under, layer L _mby catalyst A _m,ntheir the active material load M providing _m,naspect difference.So-called layer L _mactive material load M _m,nthe meaning is by catalyst A _m,nat layer L _mthe amount of the active material that inside provides.

Layer L _mactive material load M _m,ncan be by changing by catalyst A _m,nthe amount of the active material providing is revised.This can realize by for example diluting described catalyzer with the inert material of different amounts.

So-called catalyst A _m,nthe activity meaning be in predetermined reaction conditions (temperature, pressure, concentration, the residence time) under, in definition volume (=control volume), for example, for example, at definition length and internal diameter (25mm internal diameter, 1m length) reaction tubes in, catalyst A _m,nthe ability of conversion reaction thing.Therefore, in all cases, if the more high conversion of catalyzer realization response thing in pre-determined volume and under same reaction conditions, a catalyzer has the activity higher than another catalyzer.At o-Xylol or naphthalene as reactant in the situation that, therefore measure catalyst activity by the level that o-Xylol or naphthalene are converted into oxidation products.

Measure in the vertical, on the flow direction of gas phase, layer L _mcan there is identical or and different length.

According to the embodiment of method, special catalyst layer L _mlength be constant and therefore in the time carrying out the method according to this invention, do not change.

According to an embodiment, catalyzer has at least two layer L mutually _m, according at least three layer L of an embodiment _m, and according to another embodiment, at least four layer L _m.With the definite indivedual layer L of the method according to this invention _mactive material load M _m,nor by catalyst A _m,nthe active material load M providing _m,n.

In principle, the bed of packings of catalyzer will be also possible, wherein the activity of catalyzer phase along reactor axle longitudinally on continuously change.

Make subsequently the reaction gas that contains at least one reactive component that forms gas phase by described pipe.First so-called reactive component refers to and between the oxidation period of hydrocarbon, occurs i.e. formation or any compound consuming, for example o-Xylol or naphthalene.

Reactive component can be starting raw material, for example o-Xylol or naphthalene or oxygen, intermediate product, secondary species or final product.

So-called intermediate product refers to a kind of compound, and it is formed by starting raw material or other intermediate product, and transforms subsequently, is converted into final product alternatively via other intermediate product.Intermediate product is for example o-tolyl aldehyde or phthalide.

So-called secondary species refers to a kind of compound, and it is formed by starting raw material or intermediate product, but it further transforms subsequently, is not converted into final product alternatively via other intermediate product or secondary species.Secondary species contains the carbon atom fewer than final product conventionally.The example of secondary species is maleic anhydride, carbonic acid gas or carbon monoxide.

Final product is corresponding to Tetra hydro Phthalic anhydride.

In addition,, for the multi-tubular reactor of gas phase and the catalyzer phase of the pipe for multi-tubular reactor, provide a kind of model, this model description

-thermal equilibrium and,

-in the various situations for gas phase and catalyzer phase, material balance, and

-material transferring in catalyst body, and

-for prepare the reaction kinetics of Tetra hydro Phthalic anhydride by the gaseous oxidation of aromatic hydrocarbons.

Can prepare this model by means of the measurement of carrying out on reference reaction device, and finally substitute on the reactor assembly that is different from reference reaction device and measure.Therefore this model substitutes on the reactor assembly that deviates from reference reaction device the space analysis of temperature and material composition is measured.According to the present invention, this is possible, because except heat and material balance, considers material transferring and reaction kinetics in catalyst body.

In reference reaction device, temperature and the concentration of reactive component is analytically measured in space.Measure the thermal equilibrium that temperature makes the particular state that may reach reference reaction device.Measure concentration and make to reach the material balance of this state and the reaction kinetics of this state.In heat balance and mass balance, adopt the parameter of reaction kinetics.

According to an embodiment, for this model, only consider the concentration of the reactive component being formed by aromatic hydrocarbons, and do not consider the concentration of oxygen.According to another embodiment, the concentration of the reactive component relating to, all partial reactions are only considered to add at reactor inlet place to the aromatic hydrocarbons of reaction gas, for example o-Xylol in reaction.

From the data setting of reference reaction device, likely draw the conclusion about the temperature of reactive component and the measurement of the space analysis of concentration with model, therefore finally substitute these measurements.With the identical or different reactor of reference reaction device in, also likely substitute the space analysis of the temperature that realizes and concentration under the operational condition changing at reactor with this model and measure.

Start from the data of measuring at reference reaction device, can draw the conclusion that is different from the state of the reactor assembly of reference reaction device about at least one parameter with this model.In the method according to the invention, catalyzer parameter to be optimized is by layer L _min catalyst A _m,nthe active material load M providing _m,n.Due to active material load M _m,nchange, the change that has produced the transformation efficiency of reactive component.This change of transformation efficiency causes material and thermally equilibrated change.According to the present invention, now admit, by considering reaction kinetics, can realize the clearly improvement of this model, and active material load M _m,nsubstantially more accurately optimize be possible.

Thermal equilibrium is described the amount of energy of controlling volume that is fed to, the amount of the amount of the energy removing from this control volume and the energy that forms this control volume or consume.

According to an embodiment, by generation model on reference reaction device, determine this model.

According to an embodiment, model can be by providing to get off

-reference reaction device is provided, it has

-quantity is the pipe of a, and described pipe has

-diameter d, and

-length of tube l;

Wherein said pipe has tube wall, and refrigerant flows around described tube wall, and described refrigerant has average coolant temperature T _{k '};

-in pipe, provide by least one catalyzer a _mthe catalyzer phase forming, this catalyzer comprises catalyzer a mutually _mat least one layer of L _m, wherein M be assumed to be 1 and layer maximum quantity between round values, wherein catalyzer a _mcomprise the catalyst body containing containing vanadium active material;

-make the reaction gas that forms gas phase and contain at least one starting raw material by described pipe;

-by setting the operational condition of at least following content establishment reference reaction device

The specific throughput of reaction gas of-every pipe;

-the temperature in of reaction gas in the time entering reaction tubes,

In-reaction gas the certain concentration of at least one starting raw material and

-specific average coolant temperature T _{k '};

For the reference reaction device with catalyzer phase under operational condition, determine

-thermal equilibrium;

The material balance of-gas phase and catalyzer phase;

-material transferring in catalyst body, and

-reaction kinetics

Prepare thus model.

Reference reaction device can have the structure different from this reactor assembly, and it is filled by means of the method according to this invention or provides.

Reference reaction device can only comprise for example single pipe (a=1).

The pipe of reference reaction device has diameter d and length l.Diameter d is the part corresponding to the pipe of being filled mutually by catalyzer corresponding to the internal diameter of pipe and length l.Diameter d can be with diameter D identical or different and length l can be identical or different with length L.Preferably, d and l select in the scope for D and L appointment.Therefore,, according to an embodiment, d is chosen in 10 to 50mm scope, according to another embodiment, in 20 to 40mm scope.According to an embodiment, length l is chosen in 1 to 10m scope, according to another embodiment, in 2 to 5m scope.This pipe is made up of conventional material and is had conventional wall thickness, for example such for what the reactor assembly providing by the method according to this invention was explained.

Reference reaction device can have one or more discharge points for sampling, the described longitudinal arrangement along this pipe.By means of described discharge point, can determine the composition of reaction gas and determine thus reaction kinetics.

Refrigerant flows around one or more pipes of reference reaction device, and this refrigerant has average coolant temperature T _{k '}.Average coolant temperature T _{k '}can be selected as and average coolant temperature T _kidentical or different.Preferably, it is selected at as average coolant temperature T _kin the scope of specifying, and to be similar at definite average coolant temperature T _kthe mode of time general introduction is determined.

In one or more pipes of reference reaction device, provide by least one catalyzer a _mthe catalyzer phase forming, this catalyzer comprises catalyzer a mutually _mat least one layer of l _m, wherein M be assumed to be 1 and layer maximum quantity between round values.

Catalyzer a _mthere is known composition.Catalyzer a _mcan with catalyst A _midentical or different.Catalyzer is selected as and catalyst A _{m, n}similar, therefore it is similarly the vanadium containing catalysts for generation of the gaseous oxidation for aromatic hydrocarbons of Tetra hydro Phthalic anhydride." similar " meaning refers to catalyzer a in the method according to this invention _malso can be used as catalyst A _{m, n}.

Catalyzer a _mcomprise the catalyst body containing containing vanadium active material.Catalyst body and containing vanadium active material can with by identical or different according to the catalyst body existing in reactor assembly provided by the invention and active material.

If this catalyzer comprises some layers of l mutually _m, prepare model to each layer respectively.But, in the time that the parameter of model is prepared in measurement, preferably use the catalyzer phase that comprises all layers.Can be by the discharge point place sampling of arranging in correspondence or by the temperature survey on reference reaction device, determine in the import of layer and the composition of outlet reaction gas, temperature etc.

Make subsequently the one or more pipes of reaction gas by reference to reactor, this gas contains at least one starting raw material.Preferably, mixture and oxygen-containing gas that reaction gas contains o-Xylol or naphthalene or these compounds, for example air.In essence, in reference reaction device the composition of reaction gas used corresponding to the composition of reaction gas used in reactor assembly.The concentration of the mixture of o-Xylol or naphthalene or these two kinds of compounds is preferably chosen in the scope of 0.01 to 4 volume %.

Subsequently by setting the specific throughput of reaction gas of every pipe, the certain concentration of starting ingredient in reaction gas, specific average coolant temperature T _{k '}and the specific temperature in of reaction gas while entering reaction tubes, the operational condition of establishing reference reaction device.

Operational condition is chosen as with the operational condition using after the model being provided for as providing reactor assembly to carry out the method according to this invention similar.Preferably from the operational condition with selecting reference reaction device the definite value of reference reaction device, obtain about according to the conclusion of reactor assembly provided by the invention [under this reactor assembly].

Preferably, in reference reaction device, the reaction gas throughput of every pipe is set in 0.1 to 10Nm ³in the scope of/h, temperature in is in the scope of 150 to 400 DEG C, and the concentration of starting raw material (being preferably aromatic hydrocarbons) is in the scope of 0.1 to 4 volume % and average coolant temperature T _{k '}in the scope of 300 to 500 DEG C.

Subsequently, alternatively for set stable state unloading phase after, on reference reaction device, measure for the preparation of the parameter of model.Parameter is preferably selected from space analysis concentration and the space analysis temperature profile of reactive component.Preferably determine the appointment collection of parameter comprehensively.

According to the parameter of measuring, prepare model by ordinary method, for example numerical method subsequently on reference reaction device.

In the method according to this invention model used, except the heat balance and mass balance of considering traditionally, also consider material transferring in catalyst body and for prepare the reaction kinetics of Tetra hydro Phthalic anhydride by the gaseous oxidation of aromatic hydrocarbons.

Be surprised to find that, by considering material transferring in catalyst body and for prepare the reaction kinetics of Tetra hydro Phthalic anhydride by the gaseous oxidation of aromatic hydrocarbons in the preparation of model, can obtain the better conclusion substantially of change about the catalyzer parameter impact on performance characteristic.

Can be by further changing and come the value of information of further improved model and the efficiency of the method according to this invention in the time reaching thermal equilibrium and material balance.In the preferred embodiment hereinafter described of the method according to this invention, also in the preparation of reference reaction device and model, consider character pair.

According to a preferred embodiment, the thermal equilibrium that thermal equilibrium comprises catalyzer phase and the thermal equilibrium of gas phase.

The thermal equilibrium of catalyzer phase correspondingly can comprise catalyst A _m,nat least one layer of L _mthermal equilibrium, wherein the thermal equilibrium of catalyzer phase is by each layer of L _mall thermal equilibrium form.

According to a preferred embodiment, comprise catalyst A _m,nat least one layer of L _mthe thermal equilibrium of catalyzer phase comprise at least one thermal conduction in catalyst body and by the heat generation of at least one reaction.

In catalyst body, thermal conduction is described by thermal conductivity λ.Preferably, in thermal equilibrium, adopt the radially thermal conduction λ s in catalyst body.So-called radially thermal conduction refers to the thermal conduction from the center of catalyst body to the peripheral direction of catalyst body.

Thermal conduction in catalyst body can be described by following:

$\frac{1}{r_p}\·\frac{\∂}{{\∂r}_p}\·{\mathrm{\λ}}_s\·r_p\·\frac{\∂T}{{\∂r}_p}-\underset{i}{\mathrm{\Σ}}\underset{j}{\mathrm{\Σ}}{\mathrm{\ΔH}}_R^j\·v_i\·r_j\·{\mathrm{\ρ}}_{\mathrm{cat}}=0$

Equation 1,

Wherein following implication is suitable for:

r p	Radial variable (m) in catalyst body
		λ s	Heat conductivity (W/m K) in catalyst body
ΔH R	Reaction enthalpy (J/mol)
		ν	Stoichiometric coefficient (-)
r	Speed of reaction (mol/s g cat)
		ρ cat	Density (the kg/m of catalyzer 3)
i	Represent the subscript (-) of specific reactive component
		j	Represent the subscript (-) of specific reaction
T	Temperature (K)

Section 1 has been described the thermal conduction upwards of catalyst body internal diameter, from the center of catalyst body towards the direction of the periphery of catalyst body.Section 2 is described by the heat generation of reaction j.

The thermal equilibrium of gas phase preferably comprises the heat transmission between footpath thermotropism transmission and gas phase and the catalyzer phase in pipe.

Footpath thermotropism transmission in so-called pipe refers to the thermal conduction to the direction perpendicular to wall in the longitudinal axis position of Guan Zhongcong pipe.

Form catalyst A _m,ncatalyst A _m,nor catalyst body has the first side interface for gas phase, wherein in first side interface, in gas phase and catalyst A _m,nbetween occur first heat transmit, preferably in the thermal equilibrium of gas phase, adopt described first heat transmit.

According to a preferred embodiment, the amount that is fed to the heat of controlling volume forms by the heat ratio of the throughput supply with reaction gas with via the heat ratio of tube wall supply.

The heat ratio that the amount of the heat of removing from control volume is preferably removed by the throughput by gas phase and the heat ratio of removing via tube wall form.

The thermal equilibrium of gas phase can be described by following:

$u_z\·{\mathrm{\ρ}}_f\·c_p\·\frac{\∂T_f}{\∂z}={\mathrm{\λ}}_{r,f}\·(\frac{{\∂}^2{T}_f}{{\∂r}^2}+\frac{1}{r}\frac{{\∂T}_f}{\∂r})+h_f\·a_v\·(T_s-T_f)$

Equation 2,

Wherein Section 1 is described the Axial Thermal transmission in pipe, and footpath thermotropism transmission and Section 3 that Section 2 is described in pipe are described catalyst A _m,nand heat transmission between gas phase.

Following implication is suitable for:

u z	Axial velocity (m/s)
		c p	The thermal capacity (J/kg K) of gas phase
ρ f	Density (the kg/m of gas phase 3)
		T f	The temperature (K) of gas phase
T s	The temperature (K) of solid phase
		z	Axial deflection (m)
λ r，f	Radially heat conductivity (m in gas phase 2/s)
		h f	Heat transfer coefficient (W/m between gas phase and solid phase 2K)
a v	First side interface (the m providing in volume element 2/m 3)
		r	Radial variable (m)

Comprise for the material balance of specific reactive component i: be fed to the amount of the reactive component i that controls volume, the amount of the amount of the reactive component i removing and the reactive component i that transforms or form by the reaction of controlling in volume and control the amount of reactive component i residual in volume from control volume.

According to a preferred embodiment, be issued to material balance for the various situations of gas phase and catalyzer phase.

Each reactive component can reach material balance, and the material balance that wherein material balance of gas phase or catalyzer phase is reached by all or some reactive component subsequently produces.

Preferably, the transition from gas phase to catalyzer phase of the radial transport that the material balance of gas phase comprises reactive component i in pipe and reactive component.The radial transport meaning of reactive component is the transmission of reactive component perpendicular to the longitudinal axis of pipe.

Between gas phase and catalyzer, the material transmission of reactive component occurs in first side interface.

The material balance of gas phase preferably can be described by following:

$\frac{\∂(u_z\·C^i)}{\∂z}=\mathrm{\ϵ}\·D_r\·(\frac{{\∂}^2{C}^i}{{\∂r}^2}+\frac{1}{r}\frac{{\∂C}^i}{\∂r})-k_f\·a_v\·(C^i-C_s^i)$

Equation 3,

Wherein following implication is suitable for:

u z	Axial velocity (m/s)
		ε	Porosity (-)
D r	Radial diffusion coefficient (m 2/s)
		k f	Material transmission coefficient between () gas phase and solid phase
C i	Concentration (the mol/m of component i in gas phase 3)
		C i s	Concentration (the mol/m of component i on the surface of solid phase 3)
a v	First side interface (the m providing in volume element 2/m 3)
		r	() radial variable (m)
z	Axial deflection (m)

Section 1 is described radial diffusion and the Section 2 of reactive component and is described reactive component from gas phase to catalyst A _m,ntransition.

According to another embodiment, catalyst A _m,nin the material balance diffusion that comprises at least one reactive component in catalyst body or the conversion of material transferring and reactive component i.

In catalyst body, the material balance of reactive component i can preferably be described by following:

$-\frac{1}{r_p}\·\frac{\∂}{{\∂r}_p}\·r_p\·D_{\mathrm{eff}}^i\·\frac{{\∂C}_s^i}{{\∂r}_p}+\underset{j}{\mathrm{\Σ}}{v}_i\·r_j\·{\mathrm{\ρ}}_{\mathrm{cat}}=0$

Equation 4.

Section 1 is described the diffusion of reactive component i in catalyst body and Section 2 and describes the conversion of reactive component i.

Following implication is suitable for:

r p	Radial variable (m) in catalyst body
		D eff i	Effective diffusion coefficient (the m of component i 2/s)
ΔH R	Reaction enthalpy (J/mol)

ν i	The stoichiometric coefficient (-) of component i
		r j	Speed of reaction (the mol/s g of reaction j cat)
ρ cat	Density (the kg/m of catalyzer 3)
		i	Represent the subscript (-) of specific reactive component
j	Represent the subscript (-) of specific reaction
		C s i	Concentration (the mol/m of component i in solid phase 3)

Preferably, final condition is also included in heat balance and mass balance.Therefore:

(equation 5)

Wherein said variable has following implication:

r p	Radial variable (m) in catalyst body
		D eff i	Effective diffusion coefficient (the m of component i 2/s)
r	Radial variable (m)
		z	Axial deflection (m)

r j	Speed of reaction (the mol/s g of reaction j cat)
		ρ f	Density (the kg/m of gas phase 3)
i	Represent the subscript (-) of specific reactive component
		j	Represent the subscript (-) of specific reaction
C s i	Concentration (the mol/m of component i in solid phase 3)
		C f i	Concentration (the mol/m of component i in gas phase 3)
T 0	Enter the temperature (K) of gas
		T s	The temperature (K) of solid phase
T f	The temperature (K) of gas phase
		T in	The temperature (K) of inert support material
T W	The temperature (K) of tube wall
		h f	For the coefficient (W/m that between gas phase and solid phase, heat is transmitted 2K)
k f	Material transmission coefficient (m/s) between gas phase and solid phase
		M z，tot，0	Enter mass flow (the kg/s m of gas with respect to the cross-sectional area of reactor 2)
λ r，f	Radial thermal conductivity (W/m K) in gas phase
		λ r，s	Radial thermal conductivity (W/m K) in solid phase
λ s	Radial thermal conductivity (W/m K) in catalyst body
		α W，s	Heat transfer coefficient (W/m from solid phase to wall 2K)
α W，f	Heat transfer coefficient (W/m from gas phase to wall 2K)
		a v	First side interface (the m providing in volume element 2/m 3)
λ s	Thermal conductivity (W/m K) in catalyst mouldings
		R	The radius (m) of (cylindrical) pipe
R p	The radius (m) of catalyst body

At reactor inlet (z=0) (equation 5 (a)), the temperature in gas phase is identical with temperature in catalyzer and corresponding to starting temperature T ₀.

Concentration (the C of reactive component i in reactor inlet place gas phase _f) corresponding to the concentration C of supply gas _{f, 0}and the concentration of component i is constant diametrically.Axial velocity u _zdetermine by entering mass flow and gas density.

At the center of reactor (r=0) (equation 5 (b)), it is minimum or maximum that the axial flow velocity of gas phase and solid phase and temperature preferably reach.

Locate at outer tube wall (r=R) (equation 5 (c)), heat transmission from gas phase to tube wall corresponding to be transferred among gas phase or outside heat, and heat transmission in from solid phase to tube wall corresponding to be transferred among solid phase or outside heat.Preferably, there is not the exchange of material and tube wall.

In the situation that shell-type catalyzer is used as catalyst body, at the inside circumference (r of catalyst body active coating _p=0) temperature that (equation 5 (d)) locates is corresponding to the temperature of inert support material.The not exchange of generating material and inert support material.

At the neighboring of catalyst body (r _p=R _p) (equation 5 (e)) locate, from the heat of gas phase or adjacent catalyst body transmission corresponding to be transferred among catalyst mouldings or outside heat.The mass flow of the component i shifting from gas phase corresponding to be transferred among catalyst body or outside the mass flow of component i.

Catalyst A _m,nactive material load determined by the volume of active material, the volume of described active material is formed by the catalyzer geometrical shape of active material and volume and the density of density and inert core.Thus, infer the layer L of catalyzer phase _mactive material load M _m,n.

In startup or the down periods of reactor or when it is when dynamic, material balance and thermal equilibrium change in time.

But, preferably, for reactor assembly is provided, use so a kind of state, wherein to measure in time, it is constant that heat balance and mass balance keeps.This is corresponding to the steady state operation of reactor.

In all cases by the volume element formation control volume of specific dimensions.Controlling volume can be for example the whole volume that is arranged in the catalyzer phase in pipe, and catalyzer is the layer L of inside mutually _mvolume or may be even at layer L _min or catalyst body in minimum volume.

Controlling volume can for example be formed by volume element, and described volume element extends along the whole cross section of the length-specific of the longitudinal axis of reaction tubes and the inside of pipe.But controlling volume can also be formed by hollow circuit cylinder, described hollow circuit cylinder exceedes catalyzer phase length or layer L to length _mthe direction of the reaction tubes longitudinal axis of length, and extend to the direction of the cross section of this pipe above the annular region thering is specific inside radius and specific outside radius.But, the control volume with annular design is also likely provided, it extends and has specific inside radius and a specific outside radius in length-specific in the direction of the longitudinal axis of pipe.The some control volumes that formed by volume element are preferably provided, and described control volume preferably adjoins each other, and result is, can be via the layer L arranging in pipe _mor catalyzer reaches thermal equilibrium or material balance mutually.

In addition, this model comprises the reaction kinetics for the preparation of the gaseous oxidation of the aromatic hydrocarbons of Tetra hydro Phthalic anhydride.

Preferably, o-Xylol and/or naphthalene are elected to be to aromatic hydrocarbons.

In the simplest embodiment, reaction kinetics describes aromatic hydrocarbons, be preferably the conversion to Tetra hydro Phthalic anhydride of o-Xylol or naphthalene.

According to an embodiment, in this reaction kinetics, also consider at aromatic hydrocarbons to the reactive component occurring between the oxidation period of Tetra hydro Phthalic anhydride.

To between the oxidation period of Tetra hydro Phthalic anhydride, carry out some intermediate stages at aromatic hydrocarbons.In addition, form secondary species.In all cases, in these reactions, form at least one other reactive component by the first reactive component.Can should be from formation of at least one other reactive component of the first reactive component by partial reaction kinetic description, wherein determine the reaction kinetics of the gaseous oxidation of the aromatic hydrocarbons that is used for preparing Tetra hydro Phthalic anhydride from partial reaction kinetics.

Preferably, reaction kinetics depends on temperature, and description is from the speed of reaction of the formation of at least one other reactive component of the first reactive component.

More preferably, reaction kinetics does not depend on the dividing potential drop of oxygen.

In addition establish, the operational condition of multi-tubular reactor.For this reason, below setting at least

The specific throughput of reaction gas of-every pipe;

In-reaction gas the certain concentration of at least one reactive component and

The specific average coolant temperature T of-refrigerant _k.

In addition,, according to an embodiment, establish the temperature in of reaction gas in the time entering reaction tubes.

Preferably, this temperature in is chosen in the scope of 150 to 250 DEG C.

So-called specific throughput, certain concentration and specific average coolant temperature T _kthe meaning is special value in all cases, thereby determines the operational condition of multi-tubular reactor.

These parameters itself pre-determine substantially by reactor used.Therefore, for example, the throughput of the cross section of pipe and effect length reaction gas.If refrigerant is used for for example producing steam, specific average coolant temperature T _kthe refrigerant steam that produces specified quantitative may be essential.In reaction gas the concentration of at least one reactive component can be for example the limits of explosion of mixture by reactive component pre-determine.

Therefore, those skilled in the art suitably selects the operational condition of multi-tubular reactor according to its expertise.

The preferable range of the reaction gas throughput of every pipe is for for example 0.1 to 10Nm ³/ h, according to an embodiment 2 to 4.5Nm ³/ h." the Nm of unit ³" to relate in standard conditions be the volume at 1013hPa and 25 DEG C.This scope is particularly related to 20 to 30mm pipe diameter.

In reaction gas, the concentration of at least one reactive component depends on considered reactive component to a great extent.The initial concentration of o-Xylol and/or naphthalene is preferably chosen in the scope of 0.01 to 4 volume %, according to an embodiment, in the scope of 1.5 to 3.5 volume %, according to another embodiment, in the scope of 2.0 to 2.5 volume %.

Except starting ingredient, be preferably o-Xylol and/or naphthalene, reaction gas comprises oxygen-containing gas, preferably air.

According to an embodiment, the average coolant temperature T of refrigerant _kbe chosen in the scope of 300 to 500 DEG C, more preferably in the scope of 350 to 450 DEG C.

In addition, determine performance characteristic, it can the value of being assumed to be W _n.

The so-called performance characteristic meaning is the parameter that allows the efficiency of assessment catalyzer phase.Performance characteristic itself can freely be selected, as long as it makes to assess the efficiency of catalyzer phase.Can selectivity feature large as far as possible to make corresponding to the high efficiency value of catalyzer phase.This performance characteristic is for example concentration of the Tetra hydro Phthalic anhydride in the reaction gas of removing from reactor.But, can also selectivity feature as far as possible little to make corresponding to the high efficiency value of catalyzer phase.In the case, performance characteristic can be for example concentration of the secondary species in the reaction gas of removing from reactor.

This performance characteristic can the value of being assumed to be W _n.Value W _ncan be assigned in all cases special catalyst A _{m, n}.

Determine difference DELTA with model subsequently.

To this, first give limit D-value Δ _gdistribute a value.

Limit D-value Δ _gto be produced by the degree that performance characteristic optimization is carried out.If by the difference of this model value of definite performance characteristic in two steps corresponding to limit D-value Δ _gamount or lower than this amount, complete the optimization of performance characteristic.In implication of the present invention, under reaction conditions, think that two kinds of performance characteristic differences are less than limit D-value Δ _gcatalyst A _{m, n}be equivalent, because aspect the value of performance characteristic, use which kind of catalyzer indifference.

In next step, under the operational condition of multi-tubular reactor, at layer L _min active material load M is provided _{m, 1}the first catalyst A _{m, 1}determine the first value W of performance characteristic ₁.This can determine by means of reactor.But, also likely use a model for this reason.

Then, change layer L _mactive material load M _m,n, obtain a layer L be provided thus _mmiddle active material load M _{m, 2}the second catalyst A _{m, 2}.Subsequently, using a model, under the operational condition of multi-tubular reactor, is the second catalyst A _{m, 2}determine the second value W of performance characteristic ₂.Then compare the first value W ₁with the second value W ₂and definite difference DELTA.

If difference DELTA is in lower than limit D-value Δ _gamount in, layer L _mactive material load M _m,nfurther do not change and definite catalyst A _m,G.Accordingly, this provides the active material load M of optimization _m,G.Subscript " G " represents the state of optimizing by the method according to this invention in all cases.This active material load M _m,Gthe described load of corresponding the first or second catalyzer, or at the layer L between the first and second catalyzer aspect active material load _min active material load M _m,n.As explained, aspect performance characteristic, in implication of the present invention, think the different limit D-value Δ that is less than of value difference of performance characteristic _gcatalyzer or catalyzer be equivalent mutually.

But, if the amount of difference DELTA is greater than limit D-value Δ _g, further change active material load M _m,n, result is to obtain layer L _min active material load M is provided _m,nthe 3rd catalyst A _{m, 3}.Now, determine the value W of performance characteristic ₃, and with the second value W ₂difference DELTA, and by itself and limit D-value Δ _gcompare.Continue this process, until determine that performance feature difference is not more than limit D-value Δ _gtwo kinds of catalyst A _m,n.By reaching or lower than limit D-value Δ _g, obtain at layer L _min the active material load M that provides _m,Gthe catalyst A that aspect is optimized to some extent _m,G.

According to an embodiment, when changing layer L _mactive material load M _m,ntime, this program makes first significantly to change active material load and determines thus the maximum or minimum apparent position of active material load aspect performance characteristic.If the amount of difference DELTA becomes less compared with above-mentioned observed value, towards maximum or minimum mobile.If the amount of difference DELTA becomes larger compared with above-mentioned observed value, away from maximum or minimum mobile.

In the maximum or minimum environs of performance characteristic, reduce to change layer L _mactive material load M _m,nor by catalyst A _m,nthe active material load M providing _m,namplitude, result is finally to determine the different limit D-value Δ that is less than of value difference of performance characteristic _gtwo kinds of catalyst A _m,n.

Provide by limit D-value Δ _gdefinite catalyst A _m,Gand drop in the pipe of reactor, to the active material load M with optimization is provided _m,Glayer L _mand the catalyzer phase that therefore acquisition is optimized.

Catalyst A _m,Gcorresponding to the layer L of catalyzer phase _mthe catalyzer inside providing, described catalyzer provides a layer L _mthe active material load M of optimization _m,G.

For Optimization Layer L _mactive material load M _m,nor by catalyst A _m,nitself can freely select the performance characteristic of the load of the active material providing and catalyzer phase.

According to an embodiment, performance characteristic is preferably selected from

-selectivity aspect product component;

The yield of-product component;

The transformation efficiency of-reactive component;

-the concentration of secondary species in the product stream that leaves reactor.

According to a preferred embodiment, model comprises momentum balance.

Preferably, momentum balance can be described by following:

$\frac{\∂P}{\∂z}=-150\·\frac{{\mathrm{\η}}_f\·u_z}{d_p^2}\·\frac{{(1-\mathrm{\ϵ})}^2}{{\mathrm{\ϵ}}^3}-1.75\·\frac{{\mathrm{\ρ}}_f\·u_z^2}{d_p}\·\frac{(1-\mathrm{\ϵ})}{{\mathrm{\ϵ}}^3}$

Equation 6,

Wherein following implication is suitable for:

P	Pressure (Pa)
		z	Axial deflection (m)
u z	Flow velocity (m/s)
		d p	The particle diameter (m) of catalyst mouldings
η f	(Pa s) for the dynamic viscosity of gas phase
		ρ f	Density (the kg/m of gas phase 3)
ε	Porosity (-)

According to an embodiment, this catalyzer comprises catalyst A mutually _m,nat least two layer L _m, wherein at these at least two layer L _min by catalyst A _m,nthe active material load M providing _m,ndifferent.

According to an embodiment, this catalyzer comprises catalyst A mutually _m,nat least three layer L _m, wherein at these at least three layer L _min can pass through catalyst A _m,nthe active material load M obtaining _m,ndifferent.

More preferably, this catalyzer comprises catalyst A mutually _m,nat least four layer L _m, wherein at these at least four layer L _min by catalyst A _m,nthe active material load M providing _m,ndifferent.

According to an embodiment, catalyzer comprises catalyst A mutually definitely _m,nthree layer L _m, and according to another embodiment, comprise definitely catalyst A _m,nfour layer L _m.

Have two catalyzer more than layer mutually in, all layers L _mactive material load M _m,ncan change, or in all cases simultaneously, can change for a layer L only in various situations _mactive material load M _m,n.In the time carrying out the method according to this invention, comprise mutually one with upper strata L at catalyzer _msituation under, this program preferably makes active material load M _m,nonly at a layer L _minterior change and other layer remains unchanged.Therefore, the different layers of catalyzer phase is preferably optimized separately.This program can also be by certain layer L by the method according to this invention _moptimize several times.

According to an embodiment, only change indivedual layers of L of catalyzer phase _mactive material load M _m,n, and all other catalyzer parameters keep constant.In this embodiment of the method, therefore for example, the length of the layer of catalyzer phase keeps constant, and catalyst layer L _mactive material load M _m,nand catalyst A _m,nthe active material load providing changes.

In the embodiment of the method according to this invention, catalyzer comprises mutually and exceedes 2 layer L _m, wherein m can the value of being assumed to be 1,2 ... m.In all cases, each layer of L _mcontain different catalysts A _{1, n}, A _{2, n}..., A _m,n.Different layers L _mcatalyst A _{1, n}, A _{2, n}... A _m,nthe composition of active material can be similar and different.In all cases, catalyst A _{1, n}, A _{2, n}... A _m,ndifferent active material load M is provided _{1, n}, M _{2, n}..., M _m,n.Catalyst A _{1, n}active material load M is provided _{1, n}, catalyst A _{2, n}active material load M is provided _{2, n}and catalyst A _{3, n}active material load M is provided _{3, n}.

Catalyst A _m,nsubscript n will be corresponding to by catalyst A _m,nthe difference amount of the active material load providing or layer L _mdifferent activities material load M _m,n.

At layer L ₁in, the first layer L of catalyzer phase ₁in contained catalyst A _1,1a layer L is provided ₁in the first active material load M _1,1.Catalyst A _1,2will provide by catalyst A _1,2the layer L forming ₁the second active material load M _1,2, like that.

It is applicable to similarly respectively by catalyst A _{2, n}or A _{3, n}form second and the 3rd layer, and subscript n is illustrated in the various situation L of lower floor _mparticular active material load M _m,nor catalyst A _m,nthe certain loads of the active material providing.

According to an embodiment, determine successively each layer of L of catalyzer phase _mthe active material load M of optimization _m,Gor at each layer of L _min by catalyst A _m,Gthe active material load M providing _m,n.

Therefore,, in this embodiment, first, determine the first layer L by the method according to this invention ₁active material load M _{1, G}, wherein the first layer L ₁preferably be arranged on the gas inlet side of pipe.This carries out by means of the first performance perameter.Obtain by catalyst A _{1, G}provide the first active material load M _{1, G}.

Then,, if provided, determine the second layer L of catalyzer phase by the method according to this invention ₂active material load M _m,G, wherein second layer L ₂preferably be arranged in and adjoin the first layer L ₁downstream afterwards.For this reason, can use with at definite the first layer L ₁active material load M _{1, G}shi Xiangtong performance perameter, or performance perameter unlike this.Obtain by catalyst A _{2, G}the active material load M providing _{2, G}, result is, generally speaking, obtains a kind of catalyzer phase, it has the catalyst A that has that is arranged in successively downstream _{1, G}, A _{2, G}layer L ₁, L ₂.

If catalyzer comprises other layer mutually, again carry out the 3rd layer of L in the method according to this invention and definite downstream that is arranged in the second layer ₃active material load M _{3, G}, result is, obtains a kind of catalyzer phase, it has the catalyst A that has that is arranged in successively downstream _{1, G}, A _{2, G}, A _{3, G}layer L ₁, L ₂, L ₃.

For determining the 3rd layer of L ₃active material load M _{3, G}, can use with for determining first or second layer L ₁, L ₂active material load M _{1, G}or M _{2, G}the identical or different performance perameter of performance perameter.

Definite similar with the active material load of first, second or the 3rd layer, is arranged in the active material load M of other layer in downstream _m,Gdetermine.

The embodiment of the method therefore will be from three coating systems for example, and wherein therefore catalyzer comprises three catalyst layer L mutually ₁, L ₂and L ₃.Each catalyst layer will be by catalyst A _{1, n}, A _{2, n}, or A _{3, n}form.Under initial state, catalyst layer has particular active material load M _{m, 1}, result catalyzer comprises catalyst A mutually _1,1, A _2,1and A _3,1.

In first step, determine the first layer L ₁active material load M _{1, G}.For this reason, by catalyst A _1,1a layer L is provided ₁, and definite performance perameter W ₁value, for example leave the concentration of the o-Xylol in the evacuation circuit of the first layer of catalyzer phase.

Pass through via catalyst A subsequently _1,2provide, change layer L ₁active material load M _1,1.Catalyst A _1,2make from catalyst A _1,1different activities material load M _1,2available.If use shell-type catalyzer, for example, can realize by the different layers thickness of shell.Again determine subsequently performance perameter W ₂value.According to an embodiment, this carries out by means of model.

In next step, determine now difference DELTA=W ₁– W ₂, and with the limit D-value Δ of previous establishment _gcompare.This limit D-value can be the concentration difference of Tetra hydro Phthalic anhydride in for example+0.05% evacuation circuit.

If the symbol of difference DELTA is not corresponding to limit D-value Δ _gsymbol, in the opposite direction change layer a L ₁active material load, for example, by increased active material load M in above-mentioned steps _m,nreduce afterwards this active material load M _m,n.Determine subsequently the value W of performance perameter ₃.

Now, determine difference DELTA=W ₁– W ₃, and with the limit D-value Δ of previous establishment _gcompare.

If the amount of difference DELTA is greater than limit D-value Δ _gamount, the active material load of catalyst layer further changes, result is to obtain to have the active material of providing a load M _{isosorbide-5-Nitrae}catalyst A _{isosorbide-5-Nitrae}layer L ₁.Subsequently, determine performance perameter W ₄, determine difference DELTA=W ₃– W ₄and with limit D-value Δ _gamount compare.Repeat this process, until the amount of difference DELTA is than limit D-value Δ _glittle.

Obtain subsequently catalyzer phase, wherein determine the first layer L ₁active material load M _{1, G}, it is by catalyst A _{1, G}provide.

In next step, determine the second layer L of catalyzer phase ₂active material load M _{2, G}, described second layer L ₂be connected to the first layer L ₁downstream.For this reason, select suitable performance perameter, for example, leave the concentration of Tetra hydro Phthalic anhydride in the evacuation circuit of reactor.As summarize, when determining the first layer L of catalyzer phase ₁active material load M _{1, G}time, determine second layer L ₂active material load M _{2, G}.In this embodiment of method, the first layer remains unchanged.Therefore, obtain and comprise and there is catalyst A _{1, G}, A _{2, G}layer L ₁and L ₂catalyzer phase.

In next step, determine the active material load M of the 3rd layer of catalyzer phase _{3, G}.For this reason, first select suitable performance perameter, for example in the evacuation circuit of the 3rd layer that leaves catalyzer phase secondary species as the concentration of phthalide.In addition the difference DELTA that establishes a maximum, _g.

For determining the 3rd layer of L ₃active material load M _{3, G}, will have containing catalyst A _{1, G}, A _{2, G}, A _3,1layer L ₁, L ₂, L ₃catalyzer mutually as starting point and determine corresponding performance perameter W ₁.In next step, change by catalyst A _{3, n}the layer L providing ₃active material load, result be obtain have containing catalyst A _{1, G}, A _{2, G}, A _3,2layer L ₁, L ₂, L ₃catalyzer phase, then determine performance perameter W for it ₂value.

Subsequently, determine difference DELTA and with limit D-value Δ _gamount compare.This limit D-value Δ _gamount with determine by catalyst A _{1, G}, A _{2, G}the layer L providing ₁, L ₂active material load time limit D-value Δ used _gamount identical or different.

With above-mentioned to catalyst A _{1, G}, A _{2, G}definite similar, subsequently determine catalyst A _{3, G}, result is to obtain to have containing catalyst A _{1, G}, A _{2, G}, A _{3, G}layer L ₁, L ₂, L ₃catalyzer phase.Subsequently this composition of catalyzer phase is provided as to the reactor assembly for prepare Tetra hydro Phthalic anhydride by the gaseous oxidation of aromatic hydrocarbons.

Also comprise mutually other layer (for example the 4th layer of L at catalyzer ₄) situation under, as to the general introduction of the active material load of determining first, second or the 3rd layer, determine the active material load M of this layer _{4, G}.

According to another embodiment, at least one catalyst A _m,nform as thering is inert core the same with the shell-type catalyzer of at least one shell of this inert core of parcel.This shell contains active material.Can change a layer L by changing layer thickness _mactive material load.Inert core itself can have any geometrical shape, and for example can be assumed to be annular, spherical, solid cylindrical or hollow cylindrical.Preferably annular and hollow cylindrical.

Inert core can be made up of the conventional material for inertia under the reaction conditions of preparing Tetra hydro Phthalic anhydride.Be for example quartz (SiO for the suitable material of inert support ₂), porcelain, magnesium oxide, tindioxide, silicon carbide, rutile, aluminum oxide (Al ₂o ₃), the mixture of pure aluminium silicate, Magnesium Silicate q-agent (talcum), zirconium silicate or silicic acid cerium or above-mentioned materials.

According to an embodiment, the maximum diameter of inert core is 10mm, and according to another embodiment, 5mm at the most, according to another embodiment, at the most 4mm.

According to another embodiment, the maximum diameter of inert core is 1mm at least, according to another embodiment, at least 2mm.

The shell of active material is applied to inert support.This shell can form by single layer or by some layers, and wherein each layer can also have different compositions.

According to an embodiment, the thickness of shell is 10 to 1000 μ m, according to another embodiment 50 to 500 μ m.Perpendicular to the thickness of this shell of surface measurement of inert support.

According to a preferred embodiment, between inert core and the shell of encirclement inert core, form Second Edge interface, and between inert core and shell, carry out the second heat and transmit, wherein, in model, the thermal conduction in catalyzer comprises the second heat and transmits.

Particularly preferably, this core is atresia, i.e. this in-core diffusion of component that do not react.Correspondingly, in this model, provide is, via Second Edge interface, material transferring does not occur in this embodiment.

In this model, consider to describe the reaction kinetics of preparing Tetra hydro Phthalic anhydride by the gaseous oxidation of aromatic hydrocarbons.

Under simple scenario, reaction kinetics is described and is preferably the starting raw material of o-Xylol and/or naphthalene to the conversion of Tetra hydro Phthalic anhydride.

For example, but reaction kinetics is also preferably considered other reactive components that form during starting raw material is oxidizing to valuable product, intermediate product or secondary species.

According to an embodiment, can set up this reaction kinetics for whole catalyzer phase.

According to an embodiment, in all cases, reaction kinetics is for each layer of L _mcatalyzer mutually in respectively set up.

According to an embodiment, reaction kinetics is that the reaction kinetics that is converted into the partial reaction of another kind of reactive component by a kind of reactive component wherein produces.Can be by comprising the network for indivedual reactive components being converted into the partial reaction of other reactive component, describe hydrocarbon and be oxidizing to the partial reaction in Tetra hydro Phthalic anhydride.

During preferably the aromatic hydrocarbons of o-Xylol or naphthalene is converted into Tetra hydro Phthalic anhydride with different concns, occur differential responses component, wherein particular reaction has Different Effects to the reaction kinetics of being prepared Tetra hydro Phthalic anhydride by the gaseous oxidation of aromatic hydrocarbons.

According to an embodiment, the kinetics of partial reaction can be described by following:

$r_j=\frac{k_j\·p_i}{1+K_{\mathrm{oX}}\·p_{\mathrm{oX}}}$

Equation 7,

Wherein following implication is suitable for:

r j	Speed of reaction (the mol/s g of reaction j cat)
		i	Represent the subscript (-) of specific reactive component
j	Represent the subscript (-) of specific reaction
		p i	The dividing potential drop (Pa) of component i
P oX	The dividing potential drop (Pa) of component o-Xylol
		K oX	The second parameter (Pa of speed of reaction -1)
k j	The first parameter (mol/s g of speed of reaction cat?Pa)

According to another embodiment, the kinetics of partial reaction can be described by following:

r _j＝k _j·p _i

Equation 8,

Wherein following implication is suitable for:

r j	Speed of reaction (the mol/s g of reaction j cat)
		i	Represent the subscript (-) of specific reactive component
j	Represent the subscript (-) of specific reaction
		p i	The dividing potential drop (Pa) of component i
k j	Parameter (the mol/s g of speed of reaction cat?Pa)

According to embodiment, can pass through the following temperature dependency of describing speed of reaction:

$k_j=k_{0,j}\·\exp (-\frac{E_{A,j}}{R\·T})$

Equation 9,

Wherein following implication is suitable for:

k 0，j	The first constant (mol/s g of speed of reaction cat?Pa)
		E A，j	Second constant (kJ/kmol) of speed of reaction
j	Represent the subscript (-) of specific reaction
		R	General gas flow constant (kJ/kmol K)
T	Temperature (K)
		k j	A parameter (mol/s g of speed of reaction cat?Pa)

In the providing of model, reaction kinetics is preferably selected from following reactive component by consideration and sets up: carbon monoxide, carbonic acid gas, phthaldialdehyde, acetic acid, m-xylene, naphthalene, naphthoquinones, p-Xylol, o-Xylol, nonane, isopropyl benzene, para benzoquinone, o-tolualdehyde, maleic anhydride, citraconic anhydride, phenylformic acid, ortho-toluic acid, phenyl aldehyde, benzene, phenol, quinhydrones, dimethyl maleic anhydride, Tetra hydro Phthalic anhydride, phthalic acid, phthalide, toluene, 2,3-dimethyl-para benzoquinone, 2-methyl-para benzoquinone.

As explained, reactive component can be for the preparation of the starting raw material in the gaseous oxidation of the aromatic hydrocarbons of Tetra hydro Phthalic anhydride, intermediate product, secondary species or final product.

Aromatic hydrocarbons as starting raw material is preferably selected from o-Xylol and naphthalene.

As explained, partial reaction has Different Effects to reaction kinetics.According to an embodiment, setting up reaction power class hour, only consider the part in intermediate product or secondary species.Thereby reduce the expense of the method for reactor assembly is provided.

If form reactive component by intermediate product, according to an embodiment, intermediate product is selected from phthaldialdehyde, naphthoquinones, o-Xylol, o-tolualdehyde, ortho-toluic acid, phthalic acid and phthalide.

According to a preferred embodiment, intermediate product is selected from o-tolualdehyde and phthalide.

If reactive component forms by secondary component, according to an embodiment, secondary component is selected from carbon monoxide, carbonic acid gas, acetic acid, para benzoquinone, maleic anhydride, citraconic anhydride, phenylformic acid, phenyl aldehyde, benzene, phenol, to quinhydrones, toluene, 2,3-dimethyl-para benzoquinone and 2-methyl-para benzoquinone.

By the local secondary reaction kinetics adopting, the formation of secondary component is described in all cases in reaction kinetics.

According to an embodiment, secondary component is selected from carbon monoxide, carbonic acid gas and maleic anhydride.

By reducing the secondary component of considering in the foundation of reaction kinetics, can reduce equally the expense for carrying out the method according to this invention.

As above further explained, the formation of starting raw material, intermediate product and secondary species or consume and can describe the network that forms a kind of response path of reaction product by another kind of reaction product and represent by comprising in the formation of Tetra hydro Phthalic anhydride.

This network packet is converted at least one response path of the second reaction product containing description the first reaction product.By partial reaction kinetics or local secondary reaction kinetics, this conversion is described.

Preferably, this network packet is containing more than one response paths.According to an embodiment, this network packet is containing being less than 30 kinds of response paths.

According to a preferred embodiment, this network does not comprise any direct oxidation of o-Xylol to Tetra hydro Phthalic anhydride.

According to another embodiment, secondary species is carbon monoxide and/or carbonic acid gas and is formed by o-Xylol and/or Tetra hydro Phthalic anhydride in network.

According to another embodiment, secondary species is maleic anhydride and is formed by o-Xylol, tolyl aldehyde and/or Tetra hydro Phthalic anhydride in this network, preferably formed by tolyl aldehyde.

According to an embodiment, this network packet contains at least following response path:

A) o-Xylol is to carbon monoxide, carbonic acid gas (2), tolyl aldehyde (1), or to the oxidation of 2,3-xyloquinone (3);

B) tolyl aldehyde is to the oxidation of phthaldialdehyde (8), toluic acid (5), phthalide (4) or toluene (11);

C) toluic acid is to the oxidation of phthalide (6);

D) phthaldialdehyde is to the oxidation of phthalic acid (9)

E) toluene is to the oxidation of phenyl aldehyde (19), 2-methyl-para benzoquinone (12);

F) phenyl aldehyde is to the oxidation of phenylformic acid (20);

G) phenylformic acid is to the oxidation of benzene (21);

H) oxidation of benzene into phenol (22);

I) phenol is to the oxidation of quinhydrones (23);

J) quinhydrones is to the oxidation of benzoquinones (24);

K) benzoquinones is to the oxidation of maleic anhydride (25);

L) 2-methyl-para benzoquinone is to the oxidation of maleic anhydride (14);

M) 2-methyl-para benzoquinone is to the oxidation of citraconic anhydride (13);

N) citraconic anhydride is to the oxidation of acetic acid (18);

O) xyloquinone is to the oxidation of dimethyl maleic anhydride (16) or maleic anhydride (15);

P) dimethyl maleic anhydride is to the oxidation of acetic acid (17);

Q) phthalide is to the oxidation of Tetra hydro Phthalic anhydride (7);

R) phthalic acid is to the conversion of Tetra hydro Phthalic anhydride (10); And

S) Tetra hydro Phthalic anhydride is to the oxidation of phenylformic acid (26).

This network is depicted in Fig. 1.

This network preferably only comprises given response path above.

This network preferably comprises the response path of low as far as possible quantity, reduces thus the expense of carrying out the method according to this invention.

If catalyzer comprises some layers mutually, in different layers, can be preferably different networks.

According to preferred the first embodiment, this network packet contains at least following response path:

A) o-Xylol is to the oxidation of carbon monoxide, carbonic acid gas (3) and tolyl aldehyde (1);

B) tolyl aldehyde is to the oxidation of maleic anhydride (6), Tetra hydro Phthalic anhydride (7) and phthalide (4);

C) phthalide is to the oxidation of Tetra hydro Phthalic anhydride (5); With

D) Tetra hydro Phthalic anhydride is to the oxidation of carbon monoxide, carbonic acid gas (10);

This network preferably only comprises appointment response path.

This network is depicted in Fig. 2.

If catalyzer comprises some layers, the first layer L mutually ₁network preferably by forming according to the network of the first embodiment.

According to the second embodiment, this network packet contains at least following response path:

A) o-Xylol is to the oxidation of carbon monoxide, carbonic acid gas (3) and tolyl aldehyde (1);

B) tolyl aldehyde is to the oxidation of maleic anhydride (6) and phthalide (4);

C) phthalide is to the oxidation of Tetra hydro Phthalic anhydride (5); With

D) Tetra hydro Phthalic anhydride is to the oxidation of carbon monoxide, carbonic acid gas (10).

Preferably only comprise appointment response path according to the network of the second embodiment.

This network is depicted in Fig. 3.

If catalyzer comprises some layers of L mutually _m, second layer L ₂network preferably by forming according to the network of the second embodiment (Fig. 3).

According to an embodiment, the first layer L _min by catalyst A _{1, n}the activity providing lower than in the second layer by catalyst A _{2, n}the activity providing.

According to the 3rd embodiment, this network packet contains at least following response path:

A) o-Xylol is to the oxidation of tolyl aldehyde (1);

B) tolyl aldehyde is to the oxidation of phthalide (4);

C) phthalide is to the oxidation of Tetra hydro Phthalic anhydride (5); With

D) Tetra hydro Phthalic anhydride is to the oxidation of carbon monoxide, carbonic acid gas (10) and maleic anhydride (6).

Preferably only comprise appointment response path according to the network of the 3rd embodiment.

This network is depicted in Fig. 4.

If catalyzer comprises some layers mutually, the network of the 3rd layer is preferably by forming according to the network of the 3rd embodiment (Fig. 4).

According to an embodiment, the first layer L ₁catalyst A _{1, n}provide than second layer L ₂catalyst A _{2, n}lower activity, and layer L ₃middle catalyst A _{3, n}provide than second layer L ₂catalyst A _{2, n}higher activity.

If the first layer L ₁inner catalyst A _{1, n}the activity providing is higher than second layer L ₂inner catalyst A _{2, n}active and the 3rd layer of L providing ₃catalyst A _{3, n}the activity providing is higher than second layer L ₂catalyst A _{2, n}the activity providing, according to an embodiment, by forming the first layer L according to the network of the first embodiment (Fig. 2) ₁with second layer L ₂network, and network (Fig. 3) by the second embodiment forms the 3rd layer of L ₃network.Preferably, the first layer L ₁length z _{1, n}be less than second layer L ₂length z _{2, n}50%.

There are four layer L _mcatalyzer mutually in, wherein catalyst A in the first layer _{1, n}provide than second layer L ₂middle catalyst A _{2, n}higher activity, and catalyst A in the 3rd layer wherein _{3, n}provide than second layer L ₂middle catalyst A _{2, n}higher activity, in addition catalyst A in the 4th layer _{4, n}provide than the 3rd layer of L ₃middle catalyst A _{3, n}higher activity, according to an embodiment, first and second layers of L ₁, L ₂network be by according to the network of the first embodiment (Fig. 2) form, the 3rd layer of L ₃network be that network (Fig. 3) by the second embodiment forms and the 4th layer of L ₄network be by forming according to the network of the 3rd embodiment (Fig. 4).According to an embodiment, provide the first layer L ₁length z _{1, n}be less than second layer L ₂length z ₂50%.

There are four layer L _mthe embodiment of catalyzer phase in, according to an embodiment, the network of the first layer is by forming according to the network of the first embodiment (Fig. 2), second layer L ₂network be by according to the network of the second embodiment (Fig. 3) form and third and fourth layer of L ₃, L ₄network be that network (Fig. 4) by the 3rd embodiment forms.According to an embodiment, provide the 4th layer of L ₄length z _{4, n}be less than the 3rd layer of L ₃length z ₃50%.

By the catalyzer of making containing vanadium material, or say more accurately the active material of catalyzer can itself have conventional on the state of the art and known composition, wherein the specific composition of catalyzer can also be determined by means of the method according to this invention.

According to an embodiment, except vanadium oxide, catalyzer also comprises other component, the component for example providing in following table, and they are preferably included in active material with the amount in given range:

Described percentage ratio relates to the gross weight of active material in all cases.

In addition, in active material, can comprise the promotor for regulating catalyst activity.Suitable promotor is for example alkali and alkaline earth metal ions, thallium, antimony, phosphorus, iron, niobium, cobalt, molybdenum, silver, tungsten, tin, lead, zirconium, copper, gold and/or bismuth, and two or more mixture in said components.Via indivedual promotor, can affect the activity and selectivity of catalyzer or active material, particularly reduce or increase active.Increase optionally promotor and comprise for example alkalimetal oxide, but phosphorous oxides compound, particularly five phosphorus oxide, may depend on the degree of promotion, reduce the activity of catalyzer taking selectivity as cost.

If catalyzer comprises some layers mutually, the catalyzer of each layer is preferably different on its composition.

According to an embodiment, the active material content of catalyzer is between 7 to 12 % by weight, preferably between 8 to 10 % by weight.Active material (catalytically active material) preferably contains 5 to 15 % by weight V ₂o ₅, 0 to 4 % by weight Sb ₂o ₃, 0.2 to 0.75 % by weight Cs, 0 to 3 % by weight Nb ₂o ₅.Except said components, at least 90 % by weight of the remaining part of active material, preferably at least 95 % by weight, more preferably at least 98 % by weight, particularly at least 99 % by weight, more preferably at least 99.5 % by weight, especially 100 % by weight are by TiO ₂composition.This catalyzer can advantageously be used as the first catalyst layer of for example placing towards gas inlet side in the catalyzer with two or more layers.

According to an embodiment, the BET surface-area of catalyzer or active material is between 15 to 25m roughly ²between/g.In addition, preferably, the first layer L of catalyzer phase ₁, catalyst layer, has roughly 40 to 60% the length ratio of the total length (total length of the catalyst bed of existence) of all catalyst layers (layer of catalyzer phase) of existence.

According to another embodiment, catalyzer has roughly 6 to 11 % by weight, the especially active material content of 7 to 9 % by weight.This active material preferably contains 5 to 15 % by weight V ₂o ₅, 0 to 4 % by weight Sb ₂o ₃, 0.05 to 0.3 % by weight Cs, 0 to 2 % by weight Nb ₂o ₅with 0-2 % by weight phosphorus.Except said components, at least 90 % by weight of the remaining part of active material, preferably at least 95 % by weight, more preferably at least 98 % by weight, particularly at least 99 % by weight, more preferably at least 99.5 % by weight, especially 100 % by weight are by TiO ₂composition.This catalyzer can be as the second layer L of for example catalyzer phase ₂, the first layer L of the catalyzer phase of placing towards gas inlet side ₁downstream.Preferably the BET surface-area of catalyzer or active material is between roughly 15 to 25m ²between/g.In addition, preferably, this second layer accounts for roughly 10 to 30% the length ratio of the total length of all catalyst layers of existence.

According to another embodiment, the active material content of catalyzer is between about 5 to 10 % by weight, especially between 6 to 8 % by weight.Active material (catalytically active material) preferably contains 5 to 15 % by weight V ₂o ₅, 0 to 4 % by weight Sb ₂o ₃, 0 to 0.1 % by weight Cs, 0 to 1 % by weight Nb ₂o ₅with 0 to 2 % by weight phosphorus.Except said components, at least 90 % by weight of the remaining part of active material, preferably at least 95 % by weight, more preferably at least 98 % by weight, particularly at least 99 % by weight, more preferably at least 99.5 % by weight, especially 100 % by weight are by TiO ₂composition.This catalyzer can be as the above-mentioned second layer L that is for example arranged in catalyzer phase ₂the 3rd (or last) layer L of catalyzer phase in downstream ₃.Preferably the BET surface area ratio of catalyzer or active material near gas inlet be sidelong put layer slightly high, particularly about 25 to about 45m ²in the scope of/g.In addition this 3rd layer of L preferably, ₃account for about length ratio of 10 to 50% of the total length of all catalyst layers of existence.

If catalyzer comprises some layers of L mutually _m, the ratio of the total length of catalyzer phase or catalyst bed is selected in specified range according to embodiment.

Therefore, according to an embodiment, with respect to the total length of catalyzer phase, the first layer L of the catalyzer phase of placing towards gas inlet side ₁there is at least 40%, particularly at least 45%, particularly preferably at least 50% length ratio.According to an embodiment, the first layer L of the total length inner catalyst phase of catalyzer phase ₁ratio between 40 to 70%, according to another embodiment, between 40 to 55%, and according to another embodiment, between 40 to 52%.According to an embodiment, second layer L ₂total length about 10 to 40% who accounts for catalyzer phase, according to another embodiment, accounts for about 10 to 30%.In addition, according to an embodiment, the 3rd layer of L of catalyzer phase ₃length z _{3, G}with second layer L ₂length z _{2, G}ratio be chosen between about 1 and 2, according to another embodiment, between 1.2 and 1.7, according to another embodiment, between 1.3 and 1.6.

According to an embodiment, use these scopes at the catalyzer with three layers in mutually.According to an embodiment, provide in layer by catalyst A _m,nthe activity providing progressively increases from three layers of the first layers to the.

In 4-layer catalyzer, according to an embodiment, with respect to the total length of catalyzer phase or catalyzer phase, the first layer L of catalyzer phase ₁there is the length ratio between about 10% to 20%.According to an embodiment, with respect to the total length of catalyzer phase, the second layer L of catalyzer phase ₂length ratio between about 40% to 60%.According to an embodiment, with respect to the total length of catalyst bed, the 3rd or the 4th layer of L of catalyzer phase ₃, L ₄length ratio in all cases between about 15% to 40%.

According to an embodiment, provide catalyst A _m,nthe activity providing declines from the first layer to the second layer at first, then towards the 3rd or the 4th layer of increase.According to an embodiment, provide the first layer L ₁length z _{1, G}be less than the length z of the second layer _{2, G}, according to an embodiment, be less than second layer L ₂length z _{2, G}50%.

The impact that the position of focus can be chosen by indivedual catalyst layer length ratios.The temperature of focus can similarly be controlled, and result is make the inactivation of catalyzer slower, and the longer operating time of reactor to become possibility.

Can, for example by alkali-metal level in active material, affect the active line chart of catalyzer phase, and the catalyzer activity of interior each layer mutually.For example, thus can set the active line chart that wherein activity of catalyst layer inner catalyst declines from gas inlet side to pneumatic outlet side.

According to an embodiment, alkali content, preferably Cs content (in Cs) is at the second layer L of catalyzer phase ₂the first layer L of internal ratio catalyzer phase ₁inside less, and at the 3rd layer of L ₃internal ratio second layer L ₂inside less (and according to embodiment, the 3rd layer of L alternatively ₃after any layer of L _m).

According to an embodiment, the Cs content (in Cs) of catalyzer in mutually successively reduces in gas stream direction.According to a preferred embodiment, the 3rd layer (with preferably also having optional succeeding layer) do not contain Cs.Below be preferably suitable for:

(Cs content) _{the first layer}> (Cs content) _{the second layer}> ... >Cs content _{final layer}

According to an embodiment, the final layer L of catalyzer phase _mnot containing Cs.

According to another embodiment, only the final layer of catalyzer phase has phosphorus.In another embodiment, active material does not contain phosphorus in the first layer or in the second layer, or the in the situation that of 4-layer catalyzer, preferably also at the 3rd layer of L ₃inside do not contain phosphorus.(" not containing phosphorus " meaning refers to during preparation initiatively be added active material without P).

According to another embodiment, the catalyzer with three or more layer mutually in, active material content can reduce to the layer of placing towards gas outlet side from the first layer of placing towards gas inlet side.According to an embodiment, the first layer L of catalyzer phase ₁active material content can be between about 7 to 12 % by weight, according to an embodiment, between about 8 to 11 % by weight, the second layer L of catalyzer phase ₂active material content can be between about 6 to 11 % by weight, according to an embodiment, between about 7 to 10 % by weight, and the 3rd layer of L of catalyzer phase ₃active material content can be between about 5 to 10 % by weight, according to an embodiment, between about 6 to 9 % by weight.

Term " first, second, and third layer of L of catalyzer phase _m" using by following: the layer of placing towards gas inlet side is called the first layer L of catalyzer phase ₁.Two other layers, are called second and the 3rd layer of L of catalyzer phase ₂, L ₃, can also be comprised in towards the catalyzer of gas outlet side mutually in.The 3rd layer than the more close pneumatic outlet side of the second layer.

According to an embodiment, catalyzer has three or four layers mutually.3-layer catalyzer mutually in, the 3rd layer of L ₃be positioned in pneumatic outlet side.But, do not get rid of the first layer L in air-flow ₁the additional layer in downstream exists.For example, according to another embodiment, the 4th layer of L ₄(preferably, have and the 3rd layer of L ₃identical or even less active material content) also can be at the 3rd layer of L ₃afterwards.

For setting active line chart, according to an embodiment, active material content can be at first and second of catalyzer phase layer L ₁, L ₂between and/or at second and the 3rd layer of L of catalyzer phase ₂, L ₃between reduce.According to another embodiment, active material content second and the 3rd layer between reduce.According to another embodiment, the first layer L of BET surface-area from placing towards gas inlet side ₁to the 3rd layer of L placing towards gas outlet side ₃increase.The OK range of BET surface-area is for example the first layer L for catalyzer phase ₁15 to 25m ²/ g, for the second layer L of catalyzer phase ₂15 to 25m ²/ g and for the 3rd layer of L of catalyzer phase ₃25 to 45m ²/ g.

According to an embodiment, provide the first layer L of catalyzer phase ₁bET surface-area be less than the 3rd layer of L ₃bET surface-area.As first and second layers of L ₁, L ₂bET surface-area identical, and the 3rd layer of L ₃bET surface-area compare when larger, also obtain suitable catalyzer phase.According to an embodiment, towards the catalyst activity of gas inlet side lower than the catalyst activity towards gas outlet side.Can provide according to an embodiment, at least 0.05 % by weight of catalytically active material is formed by least one basic metal (in basic metal).According to an embodiment, caesium is used as to basic metal.

In addition, according to the inventor's result, provide according to an embodiment, catalyzer or active material contain niobium as a whole, 0.01 to 2 % by weight, particularly 0.5 to 1 % by weight that its amount is active material.

Catalyst A _m,ncatalyst body prepare in a usual manner, wherein the thin layer of active material is applied to inert support.For this reason, for example, solution or the suspension of the suspension of active material or precursor compound (it can be converted into the component of active material) can be sprayed onto on inert support.For example, this can occur in fluidized-bed at the temperature of 80 to 200 DEG C.But similarly, can in coating cylinder coating drum, active material be applied to inert support.

For coating program, via one or more jet pipes, the aqueous solution or the suspension of active ingredient and organic binder bond (being preferably the multipolymer of vinyl acetate/vinyl laurate, vinyl acetate/ethene or phenylethylene ethylene/propenoic acid ester) are sprayed onto on carrier heating, fluidisation.Particularly advantageously in the position of maximum economic rate of production (MERP) spray fluid, this sprinkling material can be evenly distributed in described bed thus.Continue this sprinkling program, until suspension is consumed or the active ingredient of necessary amounts is applied to this carrier.So-called active ingredient refers to the metallic compound containing in the component, particularly active material of active material.Active ingredient can be used as oxide compound or be the form of precursor compound.So-called precursor compound refers to the compound that for example can be converted into the component of active material (for example oxide compound) by heating in air.Suitable precursor compound is nitrate, carbonate, acetate or the muriate of for example metal.

According to an embodiment, in Bed or fluidized-bed, apply active material by means of suitable tackiness agent, result makes shell-type catalyzer.Suitable tackiness agent comprises the organic binder bond those skilled in the art are afamiliar with, the preferably multipolymer of vinyl acetate/vinyl laurate, ethylene acetate/acrylic acid ester, phenylethylene ethylene/propenoic acid ester, vinyl acetate/maleic acid ester and vinyl acetate/ethene, the form that is water dispersion is favourable.Particularly preferably, organic polymer or multipolymer tamanori, particularly vinyl acetate copolymer tamanori are used as to tackiness agent.Adhesive therefor is added into active material with convention amount, for example, with respect to the amount of about 10 to 20 % by weight of solids content of active material.For example, can be with reference to EP744 214.

If apply this active material at the temperature increasing to some extent of about 150 DEG C, it also can be applied to carrier without organic binder bond in the situation that.In the time using tackiness agent given above, available application temperature is for example between about 50 to 450 DEG C.In service at filling reactor, adhesive therefor burns within the short period of time of baking catalyzer.Tackiness agent is mainly used in strengthening the adhesion of active material on carrier and reduces during the transmission and abrasion in packing catalyst body into reactor time.

According to another embodiment, first, alternatively under the vehicle of preparing for catalyzer exists, first produce powder from solution and/or the suspension of active material and/or its precursor compound, subsequently in order to produce catalyzer, alternatively in adjusting and alternatively after thermal treatment, described powder is applied to inert support with hull shape formula, with the carrier that produces catalytically active metal oxides and apply in this way through heat-treated to prepare active material or to remove the processing of volatile constituent through being exposed for.

Hereinafter with reference embodiment is explained in more detail the present invention.

Embodiment

The 4-layer catalyst system with following composition and layer length packed into cooling with salt bath and had in the tubular reactor of 25mm internal diameter.In reaction tubes, a combination is arranged in central position for the 3mm thermocouple sheath of thermometric moving element.

Table 1: the composition of the active material of catalyzer

By cooling jacket, this pipe is packaged into 400cm length, refrigerant (NaNO ₂and KNO ₃eutectic mixture) via this cooling jacket flow.Measure the temperature of refrigerant at the At The Height of 50cm and 400cm along the length of pipe.The arithmetical mean of temperature is taken as to average coolant temperature T _k.

The catalyst bed of total length 300cm (catalyzer phase) is packed in pipe.Arrange catalyst bed, make whole catalyst bed be arranged in the region of cooling reaction tubes.

Transition position for the measurement point of composition of measuring reaction gas between the exit of reaction tubes and indivedual catalyst layer.

Per hour have 30-100g o-Xylol/Nm by load ³the 3-4Nm of air (o-Xylol purity >99%) and the about 1450mbar of total pressure ³air is from the top to the bottom by this pipe.

Under lower following operational condition, in thermocouple sheath, interval 10cm extracts the reaction gas composition of temperature and definite reactor exit.

Table 2: for determining the operational condition of model

According to known correlation, for example, according to VDI Heat Atlas, estimate diffusion and hot transformation parameter.

Use measure temperature and concentration data by means of software solves an equation 1 to 5 and therefore determine the reaction kinetics of each catalyzer.

The reaction kinetics for different catalysts layer of determining is made up of following partial reaction kinetics.

For layer 1, according to Fig. 2, partial reaction kinetics is described.In table 3, provide reaction power mathematic(al) parameter.

Table 3: the partial reaction kinetics of layer 1

Parameter K _oxthe value of being assumed to be 1.5bar ^-1.

For layer 2, according to Fig. 2, partial reaction kinetics is described.In table 4, provide reaction power mathematic(al) parameter.

Table 4: the partial reaction kinetics of layer 2

Parameter K _oxthe value of being assumed to be 1.5bar ^-1.

For layer 3, according to Fig. 3, partial reaction kinetics is described.In table 5, provide reaction power mathematic(al) parameter.

Table 5: the partial reaction kinetics of layer 3

Parameter K _oxthe value of being assumed to be 1.5bar ^-1.

For layer 4, according to Fig. 4, partial reaction kinetics is described.In table 6, provide reaction power mathematic(al) parameter.

Table 6: the partial reaction kinetics of layer 4

Parameter K _oxthe value of being assumed to be 1.5bar ^-1.

Without thermocouple sheath in the situation that, for cooling with salt bath and there is the tubular reactor of 25mm internal diameter, provide the optimization of catalysts with following composition and active material load.

Table 7: the composition of optimization system and active material load

For optimization of catalysts, below advantage can derive from this, described advantage is not only applicable to specific embodiment and is in general applicable to this catalyst system:

In reaction gas the more low-level and Tetra hydro Phthalic anhydride of CO and CO more at high proportion

Tetra hydro Phthalic anhydride is to CO and CO ₂more low-conversion because the concentration of the Tetra hydro Phthalic anhydride in initial two layers is no more than certain limit.

Claims (12)

1. a method for reactor assembly is provided, and described reactor assembly is for passing through at least one catalyst A _m,ntetra hydro Phthalic anhydride is prepared in the gaseous oxidation of upper aromatic hydrocarbons, and described reactor assembly comprises the catalyst body containing containing vanadium active material, wherein:

-multi-tubular reactor is provided,

-thering is the pipe of quantity b, described pipe has

-diameter D, and

-length of tube L;

Wherein said pipe has tube wall, and refrigerant flows around described tube wall, and described refrigerant has average coolant temperature T _k;

-in described pipe, provide to comprise at least one layer of L _mcatalyzer phase, wherein pass through catalyst A _m,ndescribed layer L is provided _m, wherein m be assumed to be 1 and the maximum number of plies between round values and n be 1 to n the subscript that represents special catalyst, with by described layer L _min described catalyst A _m,nactive material load M is provided _m,n; With

-make the reaction gas that forms gas phase and contain at least one reactive component by described pipe;

-be the described gas phase of described pipe and the described multi-tubular reactor of described catalyzer phase for described multi-tubular reactor, provide a kind of model, described model description

-thermal equilibrium and,

-in the various situations for described gas phase and described catalyzer phase, material balance, and

Material transferring in-described catalyst body and

-for prepare the reaction kinetics of Tetra hydro Phthalic anhydride by the gaseous oxidation of aromatic hydrocarbons;

-set up the operational condition of described multi-tubular reactor by setting at least following content

The specific throughput of described reaction gas of-every pipe;

The certain concentration of at least one reactive component described in-described reaction gas and

The specific average coolant temperature T of-described refrigerant _k;

-determine performance characteristic, described performance characteristic can the value of being assumed to be W _n;

-use described model, by following definite difference DELTA

A) to limit D-value Δ _gdistribute a value;

B) there is the first catalyst A _{m, 1}described layer L _min the first active material load M is provided _{m, 1}, and under the described operational condition of described multi-tubular reactor, determine that first of described performance characteristic is worth W ₁;

C) pass through via the second catalyst A _{m, 2}the second active material load M is provided _{m, 2}, change described layer L _mactive material load;

D) under the described operational condition of described multi-tubular reactor, use for described the second catalyst A _{m, 2}described model determine the second value W of described performance characteristic ₂;

E) more described the first value W ₁with described the second value W ₂and determine described difference DELTA;

With use catalyst A _m,nrepeating step b to e until described difference DELTA drop on lower than described limit D-value Δ _gamount in;

-provide by described limit D-value Δ _gdefinite catalyst A _m,G, and

-in the described pipe of described reactor, provide by described catalyst A _m,Gat least one layer of L of the described catalyzer phase forming _m.

2. method according to claim 1, wherein said model is by providing to get off

-reference reaction device is provided, it has

The pipe of-quantity a, described pipe has

-diameter d, and

-length of tube l;

Wherein said pipe has tube wall, and refrigerant flows around described tube wall, and described refrigerant has average coolant temperature T _k';

-in described pipe, provide by least one catalyzer a _mthe catalyzer phase forming, described catalyzer comprises described catalyzer a mutually _mat least one layer of l _m, wherein M be assumed to be 1 and the maximum quantity of layer between round values, and wherein said catalyzer a _mcomprise the catalyst body containing containing vanadium active material;

-make the reaction gas that forms gas phase and contain at least one starting raw material by described pipe;

-by setting at least following content operational condition of establishing described reference reaction device

The specific throughput of described reaction gas of-every pipe;

-in the time entering described reaction tubes described in the temperature in of reaction gas,

The certain concentration of at least one starting raw material described in-described reaction gas and

-specific average coolant temperature T _{k '};

For the described reference reaction device with described catalyzer phase under described operational condition, determine

-described thermal equilibrium;

The described material balance of-described gas phase and described catalyzer phase;

-described material transferring in described catalyst body, and

-described reaction kinetics

Prepare thus described model.

3. method according to claim 1 and 2, wherein said thermal equilibrium comprises for comprising described catalyst A _mat least one layer of L _mdescribed catalyzer phase thermal equilibrium and for the thermal equilibrium of described gas phase.

4. method according to claim 3, wherein for comprising described catalyst A _mat least one layer of L _mthe described thermal equilibrium of described catalyzer phase be included at least one thermal conduction in described catalyst body and by the heat generation of reaction.

5. according to the method described in claim 3 or 4, the described thermal equilibrium of wherein said gas phase comprises the heat transmission between footpath thermotropism transmission and described gas phase and the described catalyzer phase in described reaction tubes.

6. according to the method described in claim 1 to 5 one, the described material balance of wherein said gas phase is included in the radial transport of reactive component in described reaction tubes and described reactive component from described gas phase to described catalyst A _{m, n}described transition.

7. according to the method described in claim 1 to 6 one, wherein said catalyst A _m,nin described material balance the diffusion of reactive component and the conversion of described reactive component described in described at least one catalyst body described.

8. according to the method described in the claims one, wherein said model comprises momentum balance.

9. according to the method described in the claims one, wherein said catalyst body is formed as the shell-type catalyzer of the shell with inert core and the described inert core of parcel, and wherein said shell contains described active material.

10. according to the method described in the claims one, wherein formed by the network of the partial reaction that comprises following response path for the described reaction kinetics of preparing Tetra hydro Phthalic anhydride by the gaseous oxidation of aromatic hydrocarbons:

A) o-Xylol is to the oxidation of carbon monoxide, carbonic acid gas (3) and tolyl aldehyde (1);

B) tolyl aldehyde is to the oxidation of maleic anhydride (6), Tetra hydro Phthalic anhydride (7) and phthalide (4);

C) phthalide is to the oxidation of Tetra hydro Phthalic anhydride (5); With

D) Tetra hydro Phthalic anhydride is to the oxidation of carbon monoxide, carbonic acid gas (10);

Wherein said network is preferably described the first layer of described catalyzer phase.

11. according to the method described in the claims one, is wherein formed by the network of the partial reaction that comprises following response path for the described reaction kinetics of preparing Tetra hydro Phthalic anhydride by the gaseous oxidation of aromatic hydrocarbons:

A) o-Xylol is to the oxidation of carbon monoxide, carbonic acid gas (3) and tolyl aldehyde (1);

B) tolyl aldehyde is to the oxidation of maleic anhydride (6) and phthalide (4);

C) phthalide is to the oxidation of Tetra hydro Phthalic anhydride (5); With

D) Tetra hydro Phthalic anhydride is to the oxidation of carbon monoxide, carbonic acid gas (10);

Wherein said network is preferably described the second layer of described catalyzer phase.

12. according to the method described in the claims one, is wherein formed by the network of the partial reaction that comprises following response path for the described reaction kinetics of preparing Tetra hydro Phthalic anhydride by the gaseous oxidation of aromatic hydrocarbons:

A) o-Xylol is to the oxidation of tolyl aldehyde (1);

B) tolyl aldehyde is to the oxidation of phthalide (4);

C) phthalide is to the oxidation of Tetra hydro Phthalic anhydride (5); With

D) Tetra hydro Phthalic anhydride is to the oxidation of carbon monoxide, carbonic acid gas (10) and maleic anhydride (6);

Wherein said network is preferably described the 3rd layer of described catalyzer phase.