CN101287694B

CN101287694B - Process for preparing acrolein/acrylic acid or a mixture thereof from propane

Info

Publication number: CN101287694B
Application number: CN2006800379365A
Authority: CN
Inventors: C·克兰尔; M·迪特勒; G-P·申德勒; T-C·程; K·J·米勒-恩格尔
Original assignee: BASF SE
Current assignee: BASF SE
Priority date: 2005-10-14
Filing date: 2006-10-05
Publication date: 2011-06-15
Anticipated expiration: 2026-10-05
Also published as: CN101287694A; DE102005049699A1

Abstract

A process for preparing acrolein or acrylic acid or a mixture thereof from propane, in which propane is dehydrogenated in the presence of a heterogeneous catalyst in a reaction zone A and the propylene formed is partially oxidized heterogeneously in a reaction zone, wherein the reaction zone A is operated in the loop mode and the reaction gas mixture feedstream A fed to the reaction zone A contains added molecular hydrogen which is added to this feedstream as late as possible.

Description

Method by propane to prepare acryl aldehyde or vinylformic acid or its mixture

The present invention relates to a kind of method by propane to prepare acryl aldehyde or vinylformic acid or its mixture, wherein:

A) will import the inlet that materials flow A infeeds first reaction zone A by at least four kinds of initial materials flows 1,2,3 of different gaseous states and 4 in conjunction with the reaction gas mixtures that obtains, condition is that three kinds of initial materials flows 1,2 and 3 of gaseous state comprise propane, the initial materials flow 4 of gaseous state is that the initial materials flow 3 of molecular hydrogen and gaseous state is fresh propane

Reaction gas mixtures input materials flow A passes through at least a catalyst bed in reaction zone A, wherein on this catalyst bed, if suitable other air-flows that provides, the product gas mixture materials flow A that comprises propane and propylene forms by the part heterogeneous catalysis dehydrogenation of propane

Product gas mixture materials flow A is by leaving first reaction zone A and be divided into two kinds of product gas mixture A

streams

1 and 2 with same composition by wherein discharging, initial materials flow 1 is recycled to first reaction zone A to product gas mixture A stream 1 as gaseous state in first kind of gas circulation method

Pass among the A of first disengaging zone with from wherein removing a part or the component that is different from propane and propylene that is present in wherein comprises the resultant product gaseous mixture materials flow A ' of propane and propylene with generation more if product gas mixture A stream 2 is suitable,

B) product gas mixture materials flow A subflow 2 or product gas mixture materials flow A ' are used among second reaction zone B to load at least one oxidation reactor; In at least one oxidation reactor; Be present in product gas mixture A subflow 2 or product gas mixture materials flow A ' if in propylene contain as the methacrylaldehyde of target product or the product gas mixture materials flow B of acrylic acid or its mixture, unconverted propane and suitable unconverted propylene and excess molecular oxygen obtaining through benefiting from the selective heterogeneously catalysed partial gas phase oxidation of molecular oxygen

Product gas mixture materials flow B leaves reaction zone B and in second disengaging zone B, taking-up is present in the target product among the product gas mixture materials flow B, and from comprising unconverted propane, in the remaining residue gas of molecular oxygen and any unconverted propylene, to comprise unconverted propane, initial materials flow 2 is recycled to reaction zone A at least a portion of molecular oxygen and any unconverted propylene as gaseous state in second kind of gas circulation method, condition is the initial materials flow 2 of gaseous state, 3 and 4 combine to obtain gaseous state with the initial materials flow of any additional gaseous that is different from the initial materials flow 1 of gaseous state and to start the spray mixture materials flow, comprise and start nozzle, the mixing zone, the squirt pump of scatterer and suction nozzle starts the spray mixture materials flow to operate as starting jet with gaseous state subsequently, point to the inlet of first reaction zone A via mixing zone and scatterer by the jet transfer direction of starting of starting the nozzle decompression, the suction direction of suction nozzle is on the Way out of the product gas mixture materials flow A of first reaction zone of guiding A, and along with product gas mixture materials flow A is divided into two

seed flows

1 and 2, the pressure of the reduction that produces in suction nozzle sucks product gas mixture A stream 1 and along with simultaneously it being carried it by the mixing zone via scatterer with starting jet to mix, the reaction gas mixtures input materials flow A that forms like this is released into the inlet of first reaction zone A.

As the partial oxidation products of propylene, vinylformic acid is for finding directly or be used for for example obtaining being suitable for its form of alkyl ester the important monomer (for example referring to WO 02/,055 469 and WO 03/,078 378) of the polymkeric substance of making tackiness agent or water-absorbing polymer.Propenal is for for example preparing glutaraldehyde, methionine(Met), folic acid and acrylic acid important intermediate.

Known preparation propenal and/or acrylic acid, wherein propylene is obtained by propane by part heterogeneous catalysis dehydrogenation, and in the presence of unconverted (inertia) propane as the component of partial oxidation mixture through benefiting from the molecular oxygen heterogeneously catalysed partial gas phase oxidation to obtain comprising propenal and/or acrylic acid product mixtures (prior art of quoting in for example referring to DE-A 102 45 585 and this document).

Force with the oxygen that is existed and wherein free hydrogen neither as intermediate (from the hydrogen of the propane for the treatment of dehydrogenation directly as water (H ₂O) take out) form, also can not the dehydrogenation of detected heat release heterogeneous catalytic oxidation opposite, the heterogeneous catalysis dehydrogenation is to be understood that in this file and means on the contrary with oxydehydrogenation that its thermal characteristics is heat absorption (hydrogen burning of heat release can be used as later step and is included in the heterogeneous catalysis dehydrogenation) and wherein (routine) dehydrogenation of forming as intermediate at least of free molecule hydrogen.This usually need be different with oxydehydrogenation reaction conditions and different catalyzer.

In corresponding manner, fresh propane is to be understood that in this file and means the dehydrogenation that both has neither part nor lot in reaction zone A that the propylene partial oxygen that also has neither part nor lot among the reaction zone B changes into propenal and/or acrylic acid propane.It does not preferably participate in any chemical reaction.Usually, it provides with the preferred DE-A 102 46 119 and DE-A 102 45 585 specification sheetss and the common thick propane form that also comprises the component that is different from propane on a small quantity of realizing.This thick propane can for example obtain by DE-A 10 2,005 022 798 described methods.Thick propane comprises at least 〉=90 weight % degree usually, the preferred propane of weight % degree at least 〉=95.

Usually, above-mentioned art methods is carried out by this way, if promptly the taking-up target product remains later on and comprises in the entrap bubble of unconverted propane, molecular oxygen and suitable unconverted propylene from the product gas mixture of partial oxidation, at least a portion that comprises unconverted propane, molecular oxygen and any unconverted propylene is recycled to the heterogeneous catalysis dehydrogenation with the recycle gas pattern.

The mixture of advising (for example DE-A 10 2,004 032 129 and DE-A 10 2,005 013 039) steam, fresh propane and this recycle gas infeeds propane to the heterogeneous catalysis dehydrogenation of propylene as reaction gas mixtures input gas.The heterogeneous catalysis dehydrogenating propane should suitably carry out with the form of column plate reactor, and wherein catalyst bed is advantageously with the footpath or the platoon row that are coupling.Suitably, in this column plate reactor, use the stationary catalyst bed type.Advantageously, the catalyst bed stage number in this column plate reactor is 3.Prior art recommends autothermally to carry out heterogeneous catalysis part dehydrogenating propane.For this reason, at the catalyst bed that flows through at a distance and following on the flow direction between (fixing) catalyst bed of first (fix) catalyst bed, with the molecular oxygen form of air (for example with) with in the limited extent adding reaction gas mixtures.For example, usually be subjected to the catalysis of dehydrogenation catalyst own, can be created in the limited burning of the molecular hydrogen (and if suitable micro-at the most propane) that forms in the heterogeneous catalysis dehydrogenating propane process, its exothermicity keeps desorption temperature (adiabatic reactor structure) basically.

The comparative example 1,3 of DE-A 10 2,004 032 129 and 4 and the work embodiment of DE-A 10 2,005 010 111 in, the dehydrogenating propane of heterogeneous catalysis part as mentioned above is three dehydrogenation tubular reactors simulations by being connected in series in column plate reactor (3 catalyst bed column plates).Replace this tubular reactor that is connected in series, in these comparative examples or this work embodiment, also can use (thermal insulation) column plate reactor (having 3 stationary catalyst bed column plates under every kind of situation) of 1 and 2 with reference to the accompanying drawings.

In the column plate type of reactor of Fig. 1, flow through catalyst bed (2) under every kind of situation from outside to inside.On the contrary, in the column plate type of reactor of Fig. 2, flow through special catalyst bed (2) from inside to outside.Every kind of situation upper/lower positions (1) is represented reaction gas mixtures input gas, and (3) show air feed, and (4) are complex element.

In addition, based on the propane flow of 72 280kg/h and total air feed of 3496kg/h in the reaction gas mixtures input gas, following reactor data is fit to:

Fig. 1 reactor: total catalyst quality=30t in the reactor

Every column plate catalyst quality=10t

Height=the 5.47m of every column plate catalyst bed

Bulk density=the 1200kg/m of each catalyst bed ³

Inside radius=the 1.05m of catalyst bed

Outside radius=the 1.26m of catalyst bed

Volume=the 8.33m of every column plate catalyzer ³

Inlet tube diameter=1.4m

Reactor inside diameter=3.2m

The height for reactor of shell portion (no top cover)=21m

Hybrid element number=2

The inlet pressure of reaction mixture input gas=3.1 crust are absolute

Under every kind of situation, stand-by catalyzer is the catalyzer of corresponding comparative example or work embodiment.Use the composition of same reaction temperature and reaction gas mixtures input gas.

The preferred reactor structured material of all reactor parts is suitably for containing Si stainless steel or steel, and for example 1.4841 types is the sort of.

Fig. 2 reactor: total catalyst quality=30t in the reactor

Every column plate catalyst quality=10t

Height=the 4.84m of every column plate catalyst bed

Bulk density=the 1200kg/m of each catalyst bed ³

Inside radius=the 1.2m of catalyst bed

Outside radius=the 1.41m of catalyst bed

Volume=the 8.33m of every column plate catalyzer ³

Inlet tube diameter=1.4m

Reactor inside diameter=3.4m

The height for reactor of shell portion (no top cover)=19m

Hybrid element=2

The inlet pressure of reaction mixture input gas=3.1 crust are absolute

Under every kind of situation, stand-by catalyzer is the catalyzer of corresponding comparative example or work embodiment.Use the composition of same reaction temperature and reaction gas mixtures input gas.The preferred reactor structured material of all reactor parts is suitably for containing Si stainless steel or steel, and for example 1.4841 types is the sort of.

Suitably, the part heterogeneous catalysis dehydrogenation of propane between three catalyzer column plates basically so that the conversion of propane that feeds in the reactor is that the mode of about 20 moles of % is operated based on the single reactor journey.It is 90 moles of % regularly that the propylene of realizing forms selectivity.Single column plate is to maximum contribution migration backward in the past with increasing the operating time on flow direction of transformation efficiency.Usually, three column plate of catalyst charge on flow direction provides maximum contribution to regenerate in the past to transformation efficiency.When all column plate same degree obtain carbonization, advantageously regenerate.

When the loads on whole amount catalyzer (all sums) of whole amount propane and propylene for 〉=500l (STP)/lh and≤20 000 l (STP)/lh is (when common value is 1500-2500 l (STP)/lh), very favourable for the heterogeneous catalysis part dehydrogenation of above-mentioned propane usually.Maximum temperature of reaction in each stationary catalyst bed advantageously remains on 500-600 ℃.Particularly advantageously be, reaction gas mixtures in the above-mentioned heterogeneous catalysis part dehydrogenating propane step in column plate reactor input gas only is made up of fresh propane and the recycle gas that has been recycled to dehydrogenation from partial oxidation, and come from partial oxidation, the steam that comprises q.s is to produce the gratifying life-span of dehydrogenation catalyst bed.Even when saving when adding extra steam in the dehydrogenation, comparative example and embodiment can carry out in described column plate reactor so in other words.In addition, use among DE-A 10 2,005 009 885, DE-A 10 2,005 010111, DE-A10 2,005 009 891, DE-A 10 2,005 013 039 and the DE-A 10 2,004 032 129 argumentation about this program.In this file, the load of the catalyst bed reaction gas mixtures of a reactions steps of catalysis is to be understood that and means with standard liter (=l (STP); The reaction gas mixtures of appropriate amount standard conditions (0 ℃, 1 crust) will occupy down to rise the volume of expression) reaction mixture of the expression amount by 1 liter of catalyst bed (for example stationary catalyst bed) per hour.Yet, load also can be only based on the component of reaction gas mixtures.Under the sort of situation, it is the amount by 1 liter of catalyst bed (pure inert material bed is not counted in stationary catalyst bed) per hour for this component of representing with l (STP)/lh.

Load also can be only based on the catalytic amount that is present in the catalyst bed, and it can comprise the actual catalyst (under the sort of situation, this clearly explains) with the inert material dilution.

The shortcoming of described art methods is the also burning (propane and propylene are completely oxidized to carbonoxide and steam) of catalysis propane and propylene and molecular oxygen of catalyzer of all catalysis dehydrogenating propanes basically, but molecular oxygen has been present in usually from partial oxidation and is recycled to the recycle gas of propane heterogeneous catalysis part dehydrogenation.This is because because the catalyst life that improves in the heterogeneously catalyzed partial oxidation is measured common excessive use molecular oxygen by the partial oxidation stoichiometry.This molecular oxygen and propane and/or be present in the propylene that the catalyst combustion reaction of the propylene in the reaction mixture input gas reduced in the heterogeneous catalysis part dehydrogenating propane and form selectivity.

Therefore, advise that (seeing DE-A 102 11 275) is in multistage preparation propenal and/or vinylformic acid by propane, heterogeneous catalysis part dehydrogenating propane carries out by this way: two portions that the product gas that takes out from dehydrogenation zone is divided into same composition to be only infeeding partial oxidation with one of two portions, and another part is recycled to dehydrogenation as the component of reaction gas mixtures input gas.If being present in the molecular hydrogen from dehydrogenation itself in this recycle gas is intended to protect propane then and suitablely is present in the propylene in the reaction gas mixtures input gas in case be present in molecular oxygen in this input gas equally.This protection is burnt into water has precedence over propane and/or propylene on kinetics this fact of perfect combustion based on common molecular oxygen by the same catalyst heterogeneous catalysis.

DE-A 102 11 275 also discloses by squirt pump principle conduction dehydrogenation cycle gas (it is also referred to as the loop pattern).This document also proposes additionally molecular hydrogen to be added the possibility in the reaction gas mixtures in dehydrogenating propane.DE-A 102 11 275 does not make about need molecular hydrogen being metered into the argumentation in the jet of starting of squirt pump with certain charging rank.

The recycle gas that DE-A 10 2,004 032 129 and DE-A 10 2,005 013 039 proposes not carry out to comprise molecular oxygen and to come from heterogeneously catalyzed partial oxidation is recycled to the reaction gas mixtures input gas of heterogeneous catalysis part dehydrogenating propane.But, when a certain conversion rate of dehydrogenation, just proceed to the recirculation in the dehydrogenation reaction gaseous mixture.DE-A 10 2,004 032 129 also is proposed in before this circulation, additionally foreign molecules hydrogen is added in the reaction gas mixtures of dehydrogenation.In addition, DE-A 102,004 032 129 also propagates the loop pattern of hydrogenation.In this case, start jet only for be recycled to the recycle gas of dehydrogenation from partial oxidation.

This operator scheme disadvantage is that in this case the outside molecular hydrogen that is metered into does not still have the comprehensively protection potential of use with remarkable content as the component of product gas mixture from the oxidation of dehydrogenation lead-in portion.In addition, squirt pump also will make part have elevated pressure from the product gas mixture of part dehydrogenation, and it is released into partial oxidation.Yet, before partial oxidation, the initial gas of reaction gas mixtures that is fit to need be passed through the separate compressors additional compression usually under every kind of situation, fall to offset the pressure relevant with partial oxidation.Usually, product gas mixture A stream 2 changes into product gas mixture materials flow A ' and also carries out under pressure.Under this background, the pressure stresses that the above method of squirt pump is followed has seldom meaning.

Under this background, DE-A 10 2,005 009 885 recommends circuit pattern in work in the example II, and the reaction gas mixtures input gas that wherein is used for the dehydrogenation of propane heterogeneous catalysis part comprises by the recycle gas of partial oxidation recirculation and comprises fresh propane, foreign molecules hydrogen, minimum external steam and by the recycle gas (also can save external steam) of the recirculation of dehydrogenation own.It is used that to start jet be fresh propane, foreign molecules hydrogen, from the recycle gas of partial oxidation and the mixture of external steam.About start any order that is metered into to be observed in the jet in generation, DE-A 10 2,005 009885 does not make argumentation.This is that the applicant does not point out specifically to be metered into the requirement of order because the stainless steel pilot plant of operation is new at that time.Yet, thereafter, found in the prolonged operation time course, make in the device of (promptly being formed from steel usually) the become rusty burning of catalytic molecular hydrogen and molecular oxygen of the flying of minimum formation by stainless steel or conventional steel.The combustion heat that this disadvantage is to form to small part does not especially come into force in the heat absorption dehydrogenation in its place of needs.But even under the situation of required adiabatic dehydrogenation, it is because the adiabatic reaction equipment that can not realize ideal and partial loss at least.This causes providing the necessity of external heat, and this is relevant with the undesired cleavage method of the hydrocarbon that relates to about heat-transfer surface usually, or produces significantly reduced conversion rate of dehydrogenation.The two is disadvantageous.

Therefore, the purpose of this invention is to provide a kind of improvement method by propane to prepare acryl aldehyde or vinylformic acid or its mixture, it no longer has described shortcoming or only has them with the form that reduces in the worst case.

Therefore, found to be used for method by propane to prepare acryl aldehyde or vinylformic acid or its mixture, wherein:

streams

Pass among the A of first disengaging zone with from wherein removing a part or the component that wherein is different from propane and propylene of being present in comprises the resultant product gaseous mixture materials flow A ' of propane and propylene with generation more if product gas mixture A stream 2 is suitable,

Product gas mixture materials flow B leaves reaction zone B and takes out in second disengaging zone B, be present in the target product among the product gas mixture materials flow B, and from comprising unconverted propane, in the remaining residue gas of molecular oxygen and any unconverted propylene, to comprise unconverted propane, initial materials flow 2 is recycled to reaction zone A at least a portion of molecular oxygen and any unconverted propylene as gaseous state in second kind of gas circulation method, condition is the initial materials flow 2 of gaseous state, 3 and 4 combine to obtain gaseous state with the initial materials flow of any additional gaseous that is different from the initial materials flow 1 of gaseous state and to start the spray mixture materials flow, comprise and start nozzle, the mixing zone, the squirt pump of scatterer and suction nozzle starts the spray mixture materials flow to operate as starting jet with gaseous state subsequently, point to the inlet of first reaction zone A via mixing zone and scatterer by the jet transfer direction of starting of starting the nozzle decompression, the suction direction of suction nozzle is on the Way out of the product gas mixture materials flow A of first reaction zone of guiding A, and along with product gas mixture materials flow A is divided into two

seed flows

1 and 2, the pressure of the reduction that produces in suction nozzle is with 1 suction of product gas mixture stream and along with simultaneously it being passed through mixing zone via scatterer with its conveying with starting jet to mix, the reaction gas mixtures input materials flow A that forms like this is released into the inlet of first reaction zone A

Wherein the initial materials flow 2 of gaseous state and 3 and the initial materials flow of any additional gaseous that is different from

gaseous stream

1 and 4 at first with any order in conjunction with only adding then in the materials flow of gaseous state starting mixt and start the spray mixture materials flow to form gaseous state to obtain the initial materials flow 4 of materials flow of gaseous state starting mixt and gaseous state.

Except that characterizing part, the inventive method can be similar to document EP-A 117 146, US-A 3 161670, DE-A 33 13 573, WO 01,/96 270, DE-A 103 160 39, DE-A10 2,005 013 039, DE-A 10 2,004 032 129, DE-A 102 11 275, DE-A 102 45 585, DE-A 10 2,005 009 891, DE-A 10 2,005 010 111, DE-A10 2,005 022 798 and DE-A 10 2,005 009 885 described correlation methods and carry out.

Preferably according to the present invention, the initial materials flow 4 of gaseous state added in the materials flow of gaseous state starting mixt in the shortest time (starts the jet mixture stream with formation).In addition, the initial materials flow 4 of gaseous state adds in the materials flow of gaseous state starting mixt by this way (starts the jet mixture stream with formation): start the time of the time of jet mixture stream to first catalyst bed that comprises dehydrogenation catalyst of reaction gas mixtures input materials flow A arrival reaction zone A (on flow direction) from formation, through being not more than 30 seconds, preferably be not more than 20 or 10 seconds, advantageously be not more than 7 seconds, more preferably no more than 5 seconds, even, preferably be not more than 1 or 0.5 or 0.1 second more preferably no more than 3 seconds.

For the inventive method, take out the process useful that is present in the target product among the product gas mixture materials flow B and be all relevant therewith in prior art methods in principle.Their feature is essentially target product for example by absorption and/or condensation method and become the condensation phase by gas phase conversion.Useful absorption agent for example is water, the aqueous solution and/or organic solvent.With regard to this " condensation " of target product, keep the entrap bubble that is not transferred to the condensation phase usually, it comprises the component of the product gas mixture materials flow B that quite is difficult to condensation.These usually especially standard pressure (1 crust) down boiling point be≤those components (their total contents in entrap bubble are generally 〉=70 volume %, usually are 〉=80 volume %, are 〉=90 volume % in many cases) of-30 ℃.These mainly comprise unconverted propane, excess molecular oxygen and any unconverted propylene that is retained among the product gas mixture materials flow B.In addition, entrap bubble will comprise inert dilution gas, for example N usually ₂, CO ₂, rare gas (He, Ne, Ar etc.), CO and micro-vinylformic acid, propenal and/or H ₂O (steam content can be 25 volume % at the most in the entrap bubble, usually is 20 volume % at the most, or 10 volume % at the most, but also is that 10 volume % are following or 5 volume % are following in many cases).That this above-mentioned entrap bubble (based on the amount that is present in propane wherein) usually forms is main (usually at least 80%, or at least 90%, or at least 95% or more) therefore the entrap bubble that forms in the B of disengaging zone also especially also is called main entrap bubble in this file.

According to the present invention, usually at least a portion comprises this entrap bubble (main entrap bubble) of unconverted propane, molecular oxygen and any unconverted propylene initial materials flow 2 is recycled to reaction zone A as gaseous state with the recycle gas pattern.According to the present invention, all suitably initial materials flow 2 is recycled to reaction zone A to this entrap bubble as gaseous state.

Especially when the condensation of target product is undertaken by absorbing by organic solvent; at least a second kind of entrap bubble that comprises unconverted propane and any unconverted propylene obtains in the B of disengaging zone usually (based on the propane that is present in wherein; compare with the amount of main entrap bubble, its amount is littler basically usually).This condensation that is attributable to form also absorbs unconverted propane and any unconverted propylene mutually to a certain extent.

Take out in other processes of target product in extraction from condensation mutually, distillation, crystallization and/or desorb, this unconverted propane and any alkene reclaim and preferably are recycled to equally in the methods of the invention reaction zone A as the component of at least a other gas phases usually.

This can for example carry out (be called whole entrap bubbles under the sort of situation in this file) in having the mixture of main entrap bubble.Yet it also can carry out with the form of the air-flow for the treatment of to be recycled to independently reaction zone A.Be to be understood that this is recycled to reaction zone A and also can be used as the initial materials flow of other gaseous states and carry out.These treat that the air-flow of recirculation independently can oxygen-free or comprise oxygen (secondary entrap bubble) (for example when it obtains by condensation by air or washes as polymerization retarder by air at the rectifying tower top).

In the context of the invention, main entrap bubble, whole entrap bubbles and secondary entrap bubble form and comprise unconverted propane, molecular oxygen and any unconverted propylene and can be used as the entrap bubble that the initial materials flow 2 of gaseous state is recycled to reaction zone A.According to the present invention, obtaining in the B of disengaging zone and comprise the entrap bubble of the free-dioxygen of unconverted propane and any unconverted propylene can be with mixture with main entrap bubble and/or secondary entrap bubble (promptly for example as all the component of entrap bubbles), for example as the initial materials flow 2 of gaseous state and/or independently (in this case, entrap bubble is not the entrap bubble that is recycled to reaction zone A in the context of the invention) is recycled to reaction zone A.Under latter instance, this recirculation can not be subjected to any restriction, promptly for example even as the initial materials flow of other gaseous states carries out.Especially ought be present in be different from propane and propylene in the product gas mixture A stream 2 all components basically in the A of first disengaging zone of the inventive method from wherein removing, and when the product gas mixture materials flow A ' that produces is used to load at least one oxidation reactor, comprise unconverted propane and any unconverted propylene and in the B of disengaging zone, obtain basically all air-flows in the methods of the invention will be preferably be recycled to reaction zone A as the component of whole entrap bubbles of the initial materials flow 2 of gaseous state.Yet,, for example be used for that energy produces and/or synthesis gas preparation and/or as the diluent gas of reaction zone B if the suitable part (as described at DE-A 102 004 032 129) of also can using is used for other purposes.Yet, usually half or 2/3rds (i.e. 50 volume % or 66.6 volume %) at least in these cases, preferably 3/4, most preferably the above-mentioned entrap bubble that all obtains in the B of disengaging zone (under every kind of situation respectively about main and/or secondary or whole entrap bubbles) will preferably be recycled to reaction zone A according to the present invention as the component of the initial materials flow 2 of gaseous state.Comprise unconverted propane when only a kind of, the residue gas stream of molecular oxygen and unconverted propylene obtains (this usually is generalized case) in the B of disengaging zone, when all components basically that especially is different from propane and propylene in being present in product gas mixture A stream 2 is used to load at least one oxidation reactor by the product gas mixture materials flow A ' that wherein removes and produce in the methods of the invention in first disengaging zone, it preferably according to the present invention as the initial materials flow 2 of gaseous state all (if the suitable parts that import the same composition among the reaction zone B as diluent gas that deduct) be recycled to reaction zone A.Then, it also can be divided into two portions of same composition, and as mentioned above, only initial materials flow 2 is recycled to reaction zone A to a part as gaseous state, and another part is further used for another kind of approach.When in the B of disengaging zone, obtaining more than a kind of this residue gas stream, according to the present invention, these residue gas streams (as already mentioned) can be together in reaction zone A as initial materials flow 2 recirculation of gaseous state.Be to be understood that these residue gas streams are recycled to reaction zone A and also can carry out respectively.Also can a part of entrap bubble not as the initial materials flow 2 of gaseous state but just be recycled to reaction zone A until the response path of propane heterogeneous catalysis dehydrogenation in reaction zone A.The response path of propane heterogeneous catalysis dehydrogenation is to be understood that and means the propane that is present among the reaction gas mixtures input materials flow A passes through reaction zone A as the function of the conversion rate of dehydrogenation (transformation efficiency in the heterogeneous catalysis dehydrogenation) of this propane flowpaths among first reaction zone A.

The entrap bubble that initial materials flow 2 is recycled to reaction zone A as gaseous state is formed 〉=70 volume % degree usually in the methods of the invention, volume % degree usually 〉=80, volume % degree in many cases 〉=90, usually 〉=95 volume % degree or 〉=98 volume % degree standard pressure (1 crust) down boiling point be≤-30 ℃ component.

When all components basically that especially is different from propane and propylene in being present in product gas mixture A stream 2 was used to load at least one oxidation reactor by the product gas mixture materials flow A ' that wherein removes and produce among the A of first disengaging zone in the methods of the invention, the composition of the initial materials flow 2 of gaseous state comprised usually:

0-2 volume %, 0-1 volume % usually is a 0-0.5 volume % propylene in many cases;

0-2 volume %, 0-1 volume % usually is a 0-0.5 volume % propenal in many cases;

0-0.5 volume %, 0-0.1 volume % usually is a 0-0.05 volume % vinylformic acid in many cases;

0-4 volume %, 0-2 volume % usually is 0-1.5 volume %CO in many cases _x

10-50 volume %, 20-30 volume % propane in many cases;

0-70 volume %, 40-70 volume %N in many cases ₂

1-10 volume %, 2-5 volume % usually is 2.5-3.5 volume %O in many cases ₂With＞0 to 15 volume %H ₂O.

The temperature of the initial materials flow 2 of gaseous state usually is 50-200 ℃ in the inventive method, or 70-130 ℃, pressure is the 1.5-5 crust, preferred 3-4 crust.

For the initial materials flow 3 of gaseous state, typical temperature is 0-50 ℃ under the pressure of 3-6 crust or 4-5 crust, usually is 5-20 ℃.

In program of the present invention, the initial materials flow 4 of gaseous state is necessary for " molecular hydrogen ".In this file, be to be understood that to mean and only form or by at least 50 volume % degree by molecular hydrogen, preferred at least 60 volume % degree, or at least 70 volume % degree, or at least 80 volume % degree, or at least 90 volume % degree, or at least 95 volume % degree or at least 98 volume % degree or at least 99 volume % degree molecular hydrogens and the air-flow formed of residual content rare gas element especially.In this file, rare gas element should very generally be understood and means under appropriate reaction (in these cases for heterogeneous catalysis dehydrogenation) condition the reactive gas species of inert behavior basically, and the every kind of inert reaction gaseous fraction that adopts is preferably greater than 99 moles of % degree and keeps chemistry not change greater than 95 moles of % degree separately.The example of this rare gas element is N ₂, rare gas, CO ₂Or steam.

According to the present invention, the temperature of the initial materials flow 4 of gaseous state suitably is 20-100 ℃ in the inventive method, usually is 40-60 ℃, and pressure is the 1-5 crust.

Advantageous method of the present invention is 60-90 mole % wherein, the molecular hydrogen that preferred 75-85 mole % is present among the reaction gas mixtures input materials flow A stems from 1 (the initial materials flow 1 of gaseous state) of product gas mixture A stream, and residue 10-40 mole % or 15-25 mole % stem from the initial materials flow 4 of gaseous state.

Except that the initial materials flow 1-4 of gaseous state, the initial materials flow of useful gaseous state is steam or the spraying be made up of fine water droplet especially.This steam that comprises, for example the temperature with the initial materials flow 5 of gaseous form suitably is 100-200 ℃, usually is 120-160 ℃, pressure is the 1-4 crust.

According to the present invention, the initial materials flow 5 of this gaseous state by vapor composition will be in the methods of the invention in that initial materials flow 4 will be integrated in the materials flow of gaseous state starting mixt before adding among the latter with gaseous state.

Above-mentioned integration is suitably carried out by this way: at first the initial materials flow 5 of gaseous state is added in the initial materials flow 2 of gaseous state, and the initial materials flow 3 of gaseous state is added in the gaseous mixture that produces.

The starting mixt materials flow that produces advantageously only then by indirect heat exchanger with product gas mixture A stream 2 coolings (for example reducing to 150-350 ℃) that will be wherein from 500-600 ℃, and heating initial materials flow (for example rising to 350-530 ℃) wherein simultaneously from 20-200 ℃.The existence of steam reduces the risk of the carbonization relevant with heating.According to the present invention require use generation temperature required starting mixt materials flow purification gaseous state initial materials flow 4 with formation start jet mixture stream thereafter.Advantageously the latter's temperature is 350-550 ℃ according to the present invention, and pressure is the 2-5 crust.

Steam is especially favourable to the catalyst life in the dehydrogenation of heterogeneous catalysis part as the extra use of the initial materials flow 5 of gaseous state, as the following stated.Yet the extra use of the initial materials flow 5 of advantageously this gaseous state will be saved with the formation that stays the water that stems from the reaction of carrying out in the partial oxidation as far as possible and advantageously will be present in steam in the initial materials flow 2 of gaseous state according to the present invention.What found to be fit to according to the present invention is that steam content is 1 to 20 or to 15 or to 10 volume % among the reaction gas mixtures input materials flow A, usually is 4-6 volume %.

In the methods of the invention, especially when using product gas mixture A to flow 2, in the present invention in the more preferably variation scheme, during same at least one oxidation reactor of filling, suitably at least a portion is present in the component that is different from propane, molecular oxygen and any propylene in the entrap bubble that obtains among the B of disengaging zone according to the present invention and it is being used to form before the initial materials flow 2 of gaseous state from wherein removing.

Removing of being fit to for example is described among EP-A 117 146, US-A 3 161 670, DE-A 33 13573, DE-A 103 16 039 and the DE-A 102 45 585.

For the inventive method, suitable is when the amount of product gas mixture A stream 1 be 25-75 volume % or 30-70 volume % based on the total amount of product gas mixture materials flow A, 40-60 volume % advantageously more preferably during 50 volume %, uses the loop pattern in reaction zone A.

If according to the present invention only by gaseous state

initial materials flow

1,2,3 and 4 and the journey of the reaction gas mixtures input materials flow A that constitutes of the initial materials flow 5 of gaseous state of suitable steam in, conversion of propane (based on the one way of reaction gas mixtures input materials flow A by reaction zone A, and based on being present in the fresh propane among the reaction gas mixtures input materials flow A and stemming from the total amount of the propane of the initial materials flow 2 of gaseous state) in the methods of the invention can be 20-30 mole %.Yet, when above-mentioned conversion of propane is 30-60 mole %, preferred 35-55 mole %, more preferably during 35-45 mole %, the inventive method particularly advantageous.

For realizing above-mentioned conversion of propane,, or advantageously in reaction zone A, carry out part heterogeneous catalysis dehydrogenating propane under the operating pressure of 3 crust at the most advantageously at the 0.3-10 crust.By the thermal capacitance of water, secondly some heat absorptivity effects of the existence of steam energy balance dehydrogenation reduce partial reaction thing and product pressure with the steam dilution, and this equilibrium theory of tide to dehydrogenation has favourable influence.This diluting effect also can be by extra other rare gas elementes (N for example that uses ₂, CO ₂Deng) produce as the initial materials flow of other gaseous states.Compare with these, although as noted, steam additionally has advantageous effect to the catalyst life among the reaction zone A.

Fig. 3 shows two kinds of possible configurations (diameter described in Fig. 3 has specification " mm ") of this reaction zone A.Symbol of numeral means:

1=starts the jet mixture stream

2=product gas mixture A stream 2

The 3=stationary catalyst bed

4=starts nozzle

The 5=mixing tube

The 6=scatterer

Start the jet mixture stream for example to be 148t/h, temperature is 486 ℃, and pressure is 3.11 crust or 3.51 crust.Say that on respective sense product gas mixture A materials flow 2 is similarly 148t/h, and typical temperature for example is 600 ℃, pressure is 2.3 crust.In other words, attract wall pressure can be 2.3 crust.This is corresponding to the global cycle materials flow of 296t/h.According to the embodiment 4 of DE-A 102 19 879, catalyst system therefor can be the extrudate (total amount: for example be 30t) that 1.5mm and length are generally 3-7mm for diameter for example.Its tap density in stationary catalyst bed can for example be 1200kg/m ³(loose) is to 1350kg/m ³(dense).Just existence is generally the pressure of 2.71 crust in the catalyst bed upstream.

The important content of reaction gas mixtures input materials flow A is generally:

Propylene＞0 is 1-10 volume % to 25 volume % in many cases, usually is 2-7 volume %;

Propenal 0-1 volume % is 0-0.5 volume % in many cases, usually is 0-0.25 volume %;

Vinylformic acid 0-0.25 volume % is 0-0.05 volume % in many cases, usually is 0-0.03 volume %;

CO _x0-5 volume % is 0-3 volume % in many cases, usually is 0-2 volume %;

Propane 5-50 volume %, preferred 10-20 volume %;

Nitrogen 30-80 volume %, preferred 50-70 volume %;

Oxygen＞0 is to 5 volume %, preferred 1.0-2.0 volume %;

H ₂O 〉=0 is to 20 volume %, preferred 5.0-10.0 volume %;

H ₂0.5-10 volume %, preferred 1-5 volume %.

Yet as described in, preferred usually and pursuit reaction gas mixtures is imported steam content minimum among the materials flow A.Along with the conversion of propane of the raising of being pursued among the reaction zone A, exist the growth that exists for significant quantity steam among the reaction gas mixtures input materials flow A to require to guarantee gratifying life of dehydrogenation catalysts.

For the inventive method molecular hydrogen that advantageously exists and the mol ratio that is present in the molecular oxygen among the reaction gas mixtures input materials flow A is about 2: 1.The molecular hydrogen that exists is≤5 with the mol ratio that is present in the propane among the reaction gas mixtures input A usually simultaneously.The steam that is present in the methods of the invention among the reaction gas mixtures input materials flow A will be in many cases for 〉=0.05 to 2 or to 1 with the mol ratio that is present in propane wherein.

Advantageously, the configuration of the reaction zone A in the inventive method makes product gas mixture A comprise unconverted propane and required propylene with the propylene of 0.2 or 0.3 to 0.5 (if suitable for 0.66) and the mol ratio of propane.

Based on the one way of reaction gas mixtures input materials flow A by reaction zone A, reaction zone A can be by the heat exchange of the control isothermal configuration with deriving outer (fluid, i.e. liquid or the gas) thermal barrier of reaction zone A.Yet based on same reference, but its yet insulated design does not promptly have this with the heat exchange of deriving the outer thermal barrier control of reaction zone A basically.Under latter instance, based on the one way of the reaction gas mixtures input materials flow A that infeeds reaction zone A by reaction zone A, by taking in known references to recommend as prior art and still in measure described below, all can absorb heat (bear) or self-heating (being essentially 0) or heat release (just) of thermal characteristicss disposed.

Usually, the propane heterogeneous catalysis partly be dehydrogenated to propylene need be than higher temperature of reaction.Attainable transformation efficiency is limited by thermodynamic equilibrium usually.Common temperature of reaction is 300-800 ℃ or 400-700 ℃.Per molecule waits that the propane that is dehydrogenated to propylene obtains a part hydrogen.

High temperature and H ₂Removing of reaction product makes the equilibrium theory of tide move to target product, and it is also like this by the inertia dilution dividing potential drop to be reduced.

In principle, part heterogeneous catalysis dehydrogenating propane can carry out in (standard) adiabatic also heat absorption simultaneously among the reaction zone A.In this case, reaction gas mixtures input materials flow A is directed at least one catalyst bed under 450-700 ℃ (or 550-650 ℃).(the two all may fluidized-bed and fixed bed by it in thermal insulation; The preferred stationary catalyst bed according to the present invention) in the process because hydrogen burning, will be usually reacting by heating gaseous mixture at first, depend on 30-200 ℃ of transformation efficiency and dilution cooling then.Lower temperature of reaction can be used more long-life catalyst bed.Higher temperature of reaction promotes the transformation efficiency of raising.

From application point, the heterogeneous catalysis dehydrogenating propane general among the reaction zone A suitably realizes with the form of column plate reactor.

This suitably comprises the space catalyst bed in succession more than a catalytic dehydrogenation.The catalyst bed number can be 1-20, suitably 2-8, and 3-6.Along with the increase of stage number, be easy to realize the conversion of propane that raises further.Catalyst bed preferably radially or is axially arranged in succession.From application point, the stationary catalyst bed type is suitably used with this column plate reactor.

Under the simplest situation, stationary catalyst bed is in shaft furnace reactor or axially configuration in the annular die gap of concentric column volume grating.Yet, also can arrange annular die gap with a section on another, and after it is radially by one section, gas imported above it or below next section.

Suitably, reaction gas mixtures input materials flow A is standing middle heating by a catalyst bed in the way of next catalyst bed in the column plate reactor, for example make it by hot gas heating heat exchanger surface (for example rib) or make it wear the pipe (material suitably for containing the Si steel, especially for example the stainless steel of 1.4841 types) of superheated combustion gases heating.

When the other adiabatic operation of column plate reaction zone, based on described, especially when using DE-A 199 37107 described catalyzer, especially during those of exemplary embodiment, for the conversion of propane of≤30 moles of % enough be reaction gas mixtures to be imported materials flow A import in the dehydrogenation reactor that is preheated to 450-550 ℃ and in the column plate reactor, make it remain on this temperature range.Therefore this means whole dehydrogenating propanes and can carry out under extremely low temperature, finds this life-span particularly advantageous for stationary catalyst bed.For higher conversion of propane, reaction gas mixtures input materials flow A suitably imports in the dehydrogenation reactor that is preheated to higher temperature (these can be 700 ℃ at the most) and keep this high temperature in the column plate reactor.

Even exquisiter with direct mode carry out above-mentioned in the middle of heating (autothermal process).For this reason, the finite quantity molecular oxygen is added in the reaction gas mixtures materials flow between first catalyst bed distant place (seeing) or downstream catalyst bed usually with flow direction.Therefore generation is present in the product gas mixture can (to be subjected to the catalysis of dehydrogenation catalyst own usually), (from application point, (useful this catalyzer for example is a document US 4 788 371 also catalyst bed can be inserted the catalyzer of filling specific especially (selectivity) hydrogen catalytic combustion to have formed and/or added the limited burning of the molecular hydrogen of (if suitable propane burning of following less degree) in the reaction gas mixtures in the heterogeneous catalysis dehydrogenating propane, US 4 886 928, US 5 430 209, US 5 530 171, those of US 5 527 979 and US 5 563 314; For example this catalyst bed can with comprise dehydrogenation catalyst the bed alternately be dissolved in the column plate reactor) the column plate reactor in.According to the present invention, molecular hydrogen preferably only adds from the outside to form reaction gas mixtures input materials flow A.The heat that reaction discharges therefore can make the heterogeneous catalysis dehydrogenating propane with standard from hot mode (total thermal characteristics is essentially 0) isothermal operation pattern basically.When reactant gases when selected residence time increases in catalyst bed, therefore the dehydrogenation of propane can reduce or basically under the constant temperature, it gives long especially catalyst life.

Usually, the carrying out of oxygen charging should make that the oxygen level of reaction gas mixtures is 0.5-50 volume % or to 30 volume % based on the amount that is present in molecular hydrogen wherein as mentioned above, preferred 10-25 volume % (these relations are also favourable to the corresponding content among the reaction gas mixtures input materials flow A).Useful oxygen source is a pure molecular oxygen or with rare gas element such as CO, CO ₂, N ₂And/or the oxygen of rare gas dilution, rare oxygen, but especially also have air (preferably only using air) as oxygen source.The combustion gases that produce additionally have diluting effect usually and therefore promote the heterogeneous catalysis dehydrogenating propane.This especially sets up the steam that forms in the combustion processes.

The isothermal of heterogeneous catalysis dehydrogenating propane can be by adding sealing (for example tubular type) internals and further improve, with it advantageously, but found time before not necessarily in the space between the catalyst bed of column plate reaction zone of packing into.These internals be included on a certain temperature evaporation or fusion and when they are done like this hectic fever, and wherein temperature reduces to that this is below horizontal, the suitable solid or the liquid of condensation and rejected heat once more when they are done like this.

Advantageously, especially under the situation of described self-heating operator scheme, reaction gas mixtures input materials flow A comprises:

15-25 volume % propane,

2-6 volume % propylene,

5-20 volume % steam,

2-10 volume % molecular oxygen,

40-75 volume % dinitrogen and

＞0 to 3 volume % molecular oxygen.

According to the present invention, all measuring dehydrogenation catalyst (on all and), to go up the common load of reaction gas mixtures input materials flow A be 250-5000 h ^-1(assign 40 000 h in the high capacity pattern ^-1), preferred 10 000-25,000 l (STP)/lh, more preferably 15 000-20,000 l (STP)/lh.Corresponding propane load is generally 50-1000 h ^-1(under the high capacity pattern even reach 40 000 h ^-1), preferred 2000-5000l (STP)/lh, more preferably 3000-4000 l (STP)/lh.

In reaction zone A, program of the present invention can realize even 95 moles of % and more propylene formation selectivity under high conversion of propane.

According to being used for the selected reaction conditions of heterogeneous catalysis dehydrogenating propane, the product gas mixture A stream 2 that takes out from reaction zone A (dehydrogenation reactor) clings at 0.3-10 usually, under the pressure of preferred 1-3 crust, typical temperature is 450-650 ℃ or to 750 ℃, temperature is 500-600 ℃ in many cases.Usually, it comprises propane, propylene, H ₂, N ₂, H ₂O, methane, ethane (latter two usually as the thermolysis result of small amounts of propane and produce), ethene, butene-1, other butylene such as iso-butylene, other C ₄Hydrocarbon such as normal butane, Trimethylmethane, divinyl etc., CO and CO ₂, but also have oxygenate usually as alcohol, aldehyde and carboxylic acid (having usually≤9 carbon atoms).Also can there be the component that stems from the initial materials flow 2 of gaseous state on a small quantity.

And EP-A 117 146, DE-A 33 13 573 and US-A 3 161 670 recommend to use product gas mixture A stream 2 to load at least one oxidation reactor, thought advantageously before its propylene source for the inventive method, be present in the component that is different from propane and propylene the product gas mixture A stream 2 that comprises required propylene from wherein removing at least a portion as downstream propylene partial oxidation.In this case, the requirement of DE-A 102 11 275 should be observed.

Should emphasize at first here that all dehydrogenation catalysts well known in the prior art are useful to heterogeneous catalysis dehydrogenating propane of the present invention in principle.They can be divided into two groups roughly, especially be divided into have oxidizing property (for example chromic oxide and/or aluminum oxide) those and by at least a be deposited on the common oxidation carrier form than precious metal (as platinum) usually those.Therefore spendable dehydrogenation catalyst comprises all that WO01/96 270, EP-A 731 077, DE-A 10,211 275, DE-A 10131297, WO 99,/46 039, US-A 4 788 371, EP-A-0 705 136, WO 99,/29 420, US-A 4 220 091, US-A5 430 220, US-A 5 877 369, EP-A-0 117 146, DE-A 199 37 196, DE-A 19,937 105 and DE-A 199 37 107 recommend.Especially can use the catalyzer of embodiment 1, embodiment 2, embodiment 3 and embodiment 4 according to DE-AA199 37107.

These are the dehydrogenation catalyst that comprises the 8th transition element, lanthanum and/or the tin of 10-99.9 weight % zirconium dioxide, 0-60 weight % aluminum oxide, silicon-dioxide and/or titanium dioxide and 0.1-10 weight % at least a first or second main group element, the 3rd transition element, the periodic table of elements, and condition is that the weight percentage sum adds up to 100 weight %.

Particularly suitable embodiment in this file and the dehydrogenation catalyst in the comparative example of also being useful on.

Usually, dehydrogenation catalyst can (typically have a diameter from 1-10mm, preferred 1.5-5mm for catalyst extrudates; Length is generally 1-20mm, preferred 3-10mm), sheet (preferably with the extrudate same size) and/or catalyst rings (external diameter and length are generally 2-30mm or to 10mm, wall thickness is 1-10mm suitably under every kind of situation, or to 5mm, or to 3mm).For in fluidized-bed (or moving-bed), carrying out the heterogeneous catalysis dehydrogenation, therefore catalyzer more in small, broken bits will be used.Stationary catalyst bed according to the present invention among the preferred reaction district A.

Usually, dehydrogenation catalyst (especially for example those that use by example in this file and DE-A 19937107 recommend those (especially exemplary catalyzer among this DE-A)) is this for their energy catalysis dehydrogenating propanes and propane and molecular hydrogen incendiary.Compare with burning under competitive situations with it with dehydrogenating propane, the burning of hydrogen is all carried out on catalyzer very fasterly.

In addition, all type of reactor well known in the prior art and changing method are useful to the heterogeneous catalysis dehydrogenating propane in principle.The description of this changing method for example is present in all prior art documents of quoting about dehydrogenation catalyst and in the prior art that this file beginning is quoted.

The quite comprehensively description that is suitable for the method for dehydrogenating of the inventive method also is present in

Studies Division, Oxidative Dehydrogenation and AlternativeDehydrogenation Processes, Study Number 4192 OD, 1993,430 FergusonDrive, Mountain View, California, 94043-5272 is in the U.S..

Advantageously before its propylene source, remove at least 50 volume % according to the present invention as the inventive method partial oxidation, preferred at least 75 volume %, more preferably at least 90 volume %, most preferably at least 95 volume % are present in the component that is different from propane and propylene in the product gas mixture A stream 2.In principle, can use for this reason document DE-A 10 2,004 032 129, DE-A 10 2,005 013 039, DE-A 10 2,005 009 891, DE-A 10 2,005 010 111, DE-A 10 2,005 009 885, DE-A 10 2,005 028 798 and DE-A 102 45 585 described all remove the variation scheme.

The possibility that is suitable for requirement of the present invention for example is included in the preferred refrigerative temperature of 10-100 or 70 ℃ (preferably to) product gas mixture A stream 2 and for example clings at 0.1-50, preferred 5-15 crust, for example 0-100 ℃, contact (for example passing through it simply) with (preferred high boiling point) organic solvent (preferred hydrophobic solvent) of propane and propylene (suitably preferably on other components of product gas mixture A stream 2) wherein under preferred 20-40 ℃ the temperature.Desorb subsequently, rectifying and/or use for downstream propylene partial oxidation behavior inertia and/or as the essential gas of the reactant in this partial oxidation (for example other mixtures of air or molecular oxygen and rare gas element) stripping and can reclaim propane and propylene in mixture with pure form, this mixture can be used as the propylene source (preferably carrying out) of partial oxidation as described in German application DE-A 10 2,004 032 129 comparative examples 1.If the suitable waste gas that comprises this absorption of molecular hydrogen for example can stand transformation absorption and/or divided thin film from (for example according to DE-A 10235419), the hydrogen of removing then can be additionally as the component (as the initial materials flow 4 of gaseous state) of reaction gas mixtures input materials flow A.

Yet, the C in the above separation method ₃Hydrocarbon/C ₄More limited and the deficiency for DE-A 10245585 described requirements usually of hydrocarbon separation factor.

As by the substituting of the separating step of described absorption, for the present invention, therefore usually preferred transformation absorption or pressure rectifying.

Be suitable for absorption agent that above-mentioned absorption removes in principle for absorbing all absorption agents of propane and propylene.Absorption agent preferably is preferably hydrophobicity and/or high boiling organic solvent.The boiling point of this solvent (under the standard pressure of 1atm) advantageously is at least 120 ℃, preferably at least 180 ℃, and preferred 200-350 ℃, especially 250-300 ℃, more preferably 260-290 ℃.Flash-point (under the standard pressure of 1 crust) suitably is more than 110 ℃.Usually be suitable for and make the relative non-polar organic solvent of having of absorption agent, for example preferably do not contain the aliphatic hydrocrbon of any exterior active polar group, and aromatic hydrocarbon.Usually, need absorption agent to have very high boiling point, have very high propane and propylene solubility simultaneously.The example of absorption agent comprises aliphatic hydrocrbon, for example C ₈-C ₂₀Paraffinic hydrocarbons or alkene, or aromatic hydrocarbon is as from oil distillate in the paraffin distillatory or at the ether that has loose (requiring on the space) group on the Sauerstoffatom, or its mixture, can be to wherein adding polar solvent, for example DE-A 43 08 087 is disclosed 1, the 2-dimethyl phthalate.Phenylformic acid and phthalic acid in addition that is fit to and the ester that contains the straight chain alkanol of 1-8 carbon atom, the positive butyl ester of phenylformic acid for example, methyl benzoate, ethyl benzoate, dimethyl phthalate, diethyl phthalate, and as heat medium oil known those, biphenyl for example, the mixture of diphenyl ether and biphenyl and diphenyl ether or its chlorine derivative and triaryl alkene, for example 4-methyl-4 '-isomer of benzyl ditan and it, 2-methyl-2 '-the benzyl ditan, 2-methyl-4 '-benzyl ditan and 4-methyl-2 '-benzyl ditan and this mixture of isomers.The absorption agent that is fit to is the solvent mixture of biphenyl and diphenyl ether, is preferably Azeotrope compositions, and the solvent mixture of especially about 25 weight % biphenyl (diphenyl) and about 75 weight % phenyl ether is for example commercial available

(for example from Bayer Aktiengesellschaft).Usually this solvent mixture comprises solvent such as the dimethyl phthalate that adds with the amount based on whole solvent mixture 0.1-25 weight %.Particularly suitable absorption agent also has octane, nonane, decane, undecane, dodecane, tridecane, the tetradecane, pentadecane, n-Hexadecane, heptadecane and octadecane, has found especially that wherein the tetradecane is particularly suitable for.Advantageously used absorption agent at first satisfies above-mentioned boiling point, does not secondly have simultaneously too high molecular.The molecular weight of absorption agent advantageously is≤the 300g/ mole.The DE-A 33 13 573 described paraffin oils in addition that are fit to 8-16 carbon atom.The example of the commerical prod that is fit to be the product by the Haltermann sale, for example Halpasolsi such as Halpasol 250/340 i and Halpasol 250/275 i, and at PKWF and Printosol printing-ink under one's name.The commerical prod of preferred no aromatics, for example those of PKWFaf type.If they comprise little residual aromatics content, this can advantageously reduce and be reduced to the value that is starkly lower than 1000 ppm by weight by rectifying and/or absorption before described use.Other commerical prods that are fit to are n-paraffin (C ₁₃-C ₁₇) or from CONDEA AugustaS.p.A.'s (Italy)

GmbH,

Or SASOL Italy S.p.A., from n-paraffin (weight) C of Slovakia SLOVNAFT ₁₄-C ₁₈

The content of the said products neutral line hydrocarbon (with the area percent report of gc analysis) is generally:

Total C ₉-C ₁₃: less than 1%; C ₁₄: 30-40%; C ₁₅: 20-33%; C ₁₆: 18-26%; C ₁₇: at the most 18%; C _〉=18:＜2%.

From consisting of usually of the product of SASOL:

C ₁₃：0.48％；C ₁₄：39.8％；C ₁₅：20.8％；C ₁₆：18.9％；C ₁₇：17.3％；C ₁₈：0.91％；C ₁₉：0.21％。

From consisting of usually of the product of Haltermann:

C ₁₃：0.58％；C ₁₄：33.4％；C ₁₅：32.8％；C ₁₆：25.5％；C ₁₇：6.8％；C _≥18：＜0.2％。

In operate continuously, the composition of absorption agent will the corresponding change owing to method.

What absorb is not particularly limited.Can use all general methods well known by persons skilled in the art and condition.Product gas mixture A stream 2 and absorption agent are clung to, preferred 2-20 crust, the more preferably pressure of 5-15 crust and 0-100 ℃, especially 20 to 50 or 40 ℃ of contacts down at 1-50.Absorption can be carried out in tower or in chilled equipment.It can and flow or the operation of (preferably) adverse current.The absorption tower that is fit to for example for column plate tower (having bubble-cap and/or sieve plate), (for example specific surface area is 100-1000, or to 750m to have structured packing ²/ m ³The sheet metal filler, for example

250 Y) tower and the tower with random filler (for example filling) with the Raschig filler.Yet, also can use trickling tower and spray column, graphite block resorber, surface absorber such as thick film and film absorption device, and dull and stereotyped washer, cross spray washer and rotary scrubber.In addition, can advantageously allow to be absorbed in the bubble-plate column that has or do not have internals and carry out.

Propane and propylene can take out from absorption agent by stripping, flash distillation (flash distillation) and/or distillation.

Propane and propylene are preferably by stripping and/or desorb and take out from absorption agent.Desorb can be passed through pressure and/or temperature variation in a usual manner, preferably at 0.1-10 crust, and 1-5 crust especially, more preferably the pressure of 1-3 crust and 0-200 ℃, more preferably 30-70 ℃, carry out under preferred 30-50 ℃ the temperature especially by especially 20-100 ℃.The example that is suitable for steam stripped gas is a steam, but preferred especially oxygen/nitrogen mixture, for example air.When to use oxygen level wherein be air or oxygen/nitrogen mixture more than the 10 volume %, can be wise be before the stripping process and/or during add gas, it reduces explosive range.What be particularly suitable for this purpose is at the gas of 20 ℃ of following specific heat capacities for 〉=29J/molK, for example methane, ethane, propane (preferably), propylene, benzene, methyl alcohol, ethanol and ammonia, carbonic acid gas and water.Yet, preferably avoid C according to the present invention ₄Hydrocarbon is as this additive.Be particularly suitable for the steam stripped bubble-plate column that has in addition and do not have internals.

Propane and propylene also can be by distillation or rectifying and are taken out from absorption agent, in this case, can use those skilled in the art to know and have the tower of structured packing, random filler or suitable internal member.Optimum condition in distillation or rectifying is a 0.01-5 crust, 0.1-4 crust especially, the more preferably pressure of 1-3 crust and 50-300 ℃, especially 150-250 ℃ temperature (in the bottom).

Before it is used to change partial oxidation; the propylene source that is suitable for the reactor B of the inventive method in principle and obtains from absorption agent by stripping can infeed another operation stage; for example the partial oxidation that carries out according to the present invention of the loss (for example separation in scum dredger and/or deep filter) of the absorption agent of carrying secretly with reduction and therefore protecting simultaneously is in case absorption agent, or with the further C that improves ₃/ C ₄Centrifugation between the hydrocarbon.Removing of this absorption agent can be undertaken by all method stepss well known by persons skilled in the art.The example of preferred this embodiment of removing is that water will be from the outlet materials flow quenching of stripping apparatus in the inventive method.In this case, water washes out the outlet materials flow of this load with absorption agent and makes outlet materials flow load that water (less water has promoter action to the catalyst activity of partial oxidation of the present invention) is arranged simultaneously.This washing or quenching can be for example use the liquid collecting dish by the reverse spraying of water or carry out in specific equipment at the desorption tower top.

Be to support centrifugation, the internals that increases quenching surface-area in the quenching chamber can be installed, as those skilled in the art by known in rectifying, the absorption and desorption.

Water is preferred washing composition, is because it does not disturb the downstream part oxidation usually.Absorption agent has been had from load the outlet materials flow of propane and propylene after the flush away at water, water/absorber blend can infeed the lower volume outlet materials flow that is separated and handles and directly infeed the partial oxidation pending according to the present invention.

With for the favourable mode of the inventive method, especially when the propylene mixture by the air stripping so that it when not containing absorbed material, can directly obtain can be used for the initial action gaseous mixture of partial oxidation usually.According to the present invention, under their propane content should still not satisfied situation, also can before they are used for the propylene partial oxidation of the existence pending according to the present invention, fresh propane be added in them.By entrap bubble (the initial materials flow 2 of gaseous state), fresh propane suitably is recycled to heterogeneous catalysis dehydrogenation (as the composition of reaction gas mixtures input materials flow A) then.Fresh propane via the supply of the initial gas streams 3 of gaseous state can be then propane by suitable amount reduce.Under extreme case, when carrying out before the propylene partial oxidation, this fresh propane infeeds in this initial action gaseous mixture fully, only after passing through the partial oxidation pending according to the present invention, when it infeeds among the reaction gas mixtures input materials flow A of heterogeneous catalysis dehydrogenating propane then therefrom as the remaining ingredient in the entrap bubble, the supply that can save fresh propane required in the heterogeneous catalysis dehydrogenating propane fully.If suitable, fresh propane also can infeed any C between heterogeneous catalysis dehydrogenation and propylene partial oxidation ₃Remove (for example as stripping gas).

When reaction changes into vinylformic acid for propylene two-stage partial oxygen, some or even all fresh propane also can infeed the partial oxidation that is used for subordinate phase in the initial action gaseous mixture (yet, even when this restricted condition was set up for the initial action gaseous mixture of fs partial oxidation, this initial action gaseous mixture did not sometimes explode).This is especially favourable because propane especially originates in first partial oxidation stage (propylene → propenal) under its condition with the undesired side reaction that obtains propionic aldehyde and/or propionic acid.Favourable distributes at first and second partial oxidation fresh propane feed in addition basically equably between the stage.

Owing to this possibility in the reaction gas mixtures that fresh propane is infeeded the partial oxidation stage, can prepare the composition of inexplosive these initial action gaseous mixture reliably.If suitable, a part of entrap bubble also can be directly recycled to propylene and/or propenal moiety oxidation for this reason.If necessary, also can use the mixture of fresh propane and entrap bubble for this reason.Deciding factor in the problem whether the initial action gaseous mixture of answering the partial oxidation stage explodes is whether to disseminate (describing referring to the experiment among DIN 51649 and the WO 04/007405) by the burning (igniting, blast) that local ignition source (as luminous platinum filament) causes under certain initial condition (pressure, temperature) in the initial action gaseous mixture.When having diffusion, mixture should be called blast here.When not existing when disseminating, mixture ranges inexplosive in this file.When initial action gaseous mixture when being inexplosive, this also is applied to the reaction gas mixtures (referring to WO 04/,007 405) that forms in propylene partial oxidation process of the present invention.

Yet, usually in the methods of the invention only reaction gas mixtures input materials flow A will comprise the fresh propane of adding.

The required fresh propane of the method wherein of the invention still further relates to is to many parts (75% degree only for example, or 50% degree only, or 25% degree only) infeeds among the reaction gas mixtures input materials flow A, and infeed the Process configuration in the initial gas of reaction gas mixtures of partial oxidation to small part (be generally residuum, if all suitable).In addition, program can be as described in the WO 01,/96 170, and it forms the application's integral part.

In a manner known way with molecular oxygen with the propylene heterogeneous catalyzed gas phase partial oxidation become vinylformic acid in principle along reaction coordinate with two in succession step carry out, wherein at first produce propenal, secondly propenal becomes vinylformic acid.

With two in succession this reaction sequence of step in time opened and on the propenal stage (main propenal form stage), stop the inventive method in a manner known way and carry out target product in this stage and take out, or make the inventive method proceed to main vinylformic acid continuously to form and only carry out then the possibility that target product takes out.

When the inventive method proceeds to main vinylformic acid and forms, according to the present invention advantageously in two stages, promptly in two oxidation stages of arranged in series, carry out present method, in this case, in each of two oxidation stages, suitably adjust stationary catalyst bed to be used and preferably other reaction conditionss, for example temperature of stationary catalyst bed in the best way.

Although containing element Mo, the Fe that forms for the activity of such catalysts that is particularly suitable as first oxidation stage (propylene → propenal), the poly-metal deoxide of Bi be second oxidation stage of catalysis (propenal → vinylformic acid) to a certain extent also, consist of the poly-metal deoxide of at least a containing element Mo and V for usually preferred its activity of second oxidation stage.

Therefore the inventive method of the heterogeneously catalyzed partial oxidation of propylene especially is suitable for the one-level method of making preparation propenal (if with suitable vinylformic acid) or as first step of reaction of two-stage vinylformic acid preparation on the stationary catalyst bed of forming as activity for the poly-metal deoxide that has at least a containing element Mo, Fe and Bi at catalyzer.

If become propenal and suitable vinylformic acid or use initial action gaseous mixture of the present invention to become acrylic acid realization can be propylene two-stage heterogeneously catalyzed partial oxidation propylene one-level heterogeneously catalyzed partial oxidation particularly as document EP-A 700 714 (first step of reaction; As the corresponding counter-flow pattern above tube bundle reactor also as described in the there with salt bath and initial action gaseous mixture), EP-A 700893 (second step of reaction; As described in the there, and with corresponding counter-flow pattern), WO 04/085369 (this document especially is considered to the integral part of this document) (as two-stage approach), WO 04,/85 363, carry out DE-A 103 13 212 (first step of reaction), EP-A 1 159 248 (as two-stage approach), EP-A 1 159 246 (second step of reaction), EP-A 1 159 247 (as two-stage approach), DE-A 199 48 248 (as two-stage approach), DE-A 101 01 695 (one-level or two-stage), WO 04/,085 368 (as two-stage approach), DE-A 10 2,004 021 764 (two-stage), WO 04/,085 362 (first step of reaction), WO 04/,085 370 (second step of reaction), WO 04/,085 365 (second step of reaction), WO 04/,085 367 (two-stage), EP-A 990 636, EP-A 1 007 007 and EP-A 1 106 598 described carrying out.

This especially sets up for all working embodiment contained in these documents.They can carry out as described in these documents, are initial action gaseous mixture 2 of the present invention but difference is to be used for the initial action gaseous mixture of first step of reaction (propene to acrolein).For rest parameter, program is general (especially about the reactant load on stationary catalyst bed and the stationary catalyst bed) among the work embodiment of document as mentioned.When the program among the above-mentioned work embodiment of prior art is when having secondary oxygen (secondary air) charging between two stages and two step of reaction, charging is carried out in the mode that is fit to, but regulate it amount so that in the batch mixtures of second step of reaction the mol ratio of molecular oxygen and propenal corresponding to such effect among the work embodiment of mentioning document.The initial action gaseous mixture of the present invention of heterogeneously catalysed partial gas phase oxidation can for example obtain by adding in the product gas mixture A stream 2 or add among the product gas mixture materials flow A ' as the required as many molecular oxygen of partial oxidation with plain mode.This supply can be carried out with the form of pure molecular oxygen or with the form of mixtures (or only in the presence of rare gas element) of molecular oxygen and rare gas element.Preferred air is as this mixture according to the present invention.For necessity of the present invention is that this oxygen supply makes product gas mixture B still comprise unconverted molecular oxygen by this way.

Usually, the mol ratio that is present in the propylene in molecular oxygen and the initial action gaseous mixture that is present in partial oxidation in the initial action gaseous mixture of partial oxidation for 〉=1 and≤3.

The multi-metal-oxide catalyst that is particularly suitable for concrete step of reaction repeatedly describe in the past and for those skilled in the art known.For example EP-A 253 409 points out corresponding US on page 5.

Also open for concrete oxidation stage advantageous catalysts by DE-A 4 431 957, DE-A 10 2,004,025 445 and DE-A 4 431 949.This is especially to those establishments of above-mentioned document formula of I.For the particularly advantageous catalyzer of concrete oxidation stage openly by document DE-A 103 25 488, DE-A 10,325 487, DE-A 103 53 954, DE-A 103 44 149, DE-A 103 51 269, DE-A 10,350 812, DE-A 103 50 822.

For the step of reaction of the present invention that the propylene heterogeneous catalyzed gas phase partial oxidation is become propenal or vinylformic acid or its mixture, useful multimetal oxide compositions is in principle for comprising all multimetal oxide compositions that Mo, Bi and Fe form as activity.

These are the poly-metal deoxide active composition of the general formula I of DE-A 199 55 176 especially, the poly-metal deoxide active composition of the general formula I of DE-A 199 48 523, the poly-metal deoxide active composition of the general formula I of DE-A 101 01 695, II and III, the poly-metal deoxide active composition of the general formula I of DE-A 199 48 248, II and III, with the poly-metal deoxide active composition of general formula I, II and the III of DE-A 199 55 168, and EP-A 700 714 described poly-metal deoxide active compositions.

Also has the document ResearchDisclosure No.497012 on August 29th, 2005 for what this step of reaction was fit to, DE-A 100 46 957, DE-A 100 63 162, DE-C 3 338380, DE-A 199 02 562, EP-A 15 565, DE-C 2 380 765, EP-A 8 074 65, EP-A 279 374, DE-A 330 00 44, EP-A 575 897, US-A 4 438 217, DE-A 19855913, WO 98,/24 746, DE-A 197 46 210 (those of general formula I I), JP-A 91/,294 239, EP-A 293 224 and the EP-A 700 714 disclosed Mo that comprise, the multi-metal-oxide catalyst of Bi and Fe.This is particularly useful for the exemplary of these documents, those of preferred especially in these EP-A 15 565, EP-A 575 897, DE-A 197 46 210 and DE-A 198 55913.The catalyzer of the embodiment 1c of lay special stress on EP-A 15 565 and will be with corresponding manner preparation but its active composition has composition Mo in this context ₁₂Ni _6.5Zn ₂Fe ₂Bi ₁P _0.0065K _0.06O _x10 SiO ₂Catalyzer.Also emphasize (the stoichiometry: Mo of the example with sequence number 3 of DE-A 198 55 913 ₁₂Co ₇Fe ₃Bi _0.6K _0.08Si _1.6O _x) be the non-loaded hollow cylinder body catalyst of 5mm * 3mm * 2mm (external diameter * height * internal diameter) as geometrical dimension, and the non-loaded poly-metal deoxide II catalyzer of DE-A 197 46 210 embodiment 1.Also should mention the multi-metal-oxide catalyst of US-A 4 438 217.When the geometrical dimension of these hollow cylinders is 5.5mm * 3mm * 3.5mm, or 5mm * 2mm * 2mm, or 5mm * 3mm * 2mm, or when 6mm * 3mm * 3mm or 7mm * 3mm * 4mm (external diameter * height * internal diameter of respectively doing for oneself), the latter especially sets up.Other possible catalyzer geometrical shapies are that (for example long 7.7mm and diameter are 7mm to extrudate herein; Or long 6.4mm and diameter are 5.7mm).

Can be contained in general formula I V if be applicable to the multiple poly-metal deoxide active composition of propene to acrolein and suitable acrylic acid step mostly

Mo ₁₂Bi _aFe _bX ¹ _cX ² _dX ³ _eX ⁴ _fO _n (IV)

Wherein variable is defined as follows separately:

X ¹=nickel and/or cobalt,

X ²=thallium, basic metal and/or alkaline-earth metal,

X ³=zinc, phosphorus, arsenic, boron, antimony, tin, cerium, lead and/or tungsten,

X ⁴=silicon, aluminium, titanium and/or zirconium,

A=0.5 to 5,

B=0.01 to 5, preferred 2 to 4,

C=0 to 10, preferred 3 to 10,

D=0 to 2, preferred 0.02 to 2,

E=0 to 8, preferred 0-5,

F=0 to 10 and

N=is by the valency of the element outside the deoxygenation among the IV and the number of frequency decision.

They can obtain (for example seeing DE-A 4 023 239) in a manner known way and moulding is to obtain spheroid, ring or right cylinder or with coated catalysts routinely basically, and the form that promptly is coated with the premolding inert support of active composition is used.Certainly, they also can be with powder type as catalyzer.

In principle, the active composition of general formula I V can be with plain mode by being obtained having stoichiometric very close corresponding to them by its basal component source that is fit to, preferred drying composite in small, broken bits and 350-650 ℃ down calcining it and prepare.Calcining can be under rare gas element or under oxidizing atmosphere such as air (mixture of rare gas element and oxygen), and at reducing atmosphere (for example rare gas element, NH ₃, CO and/or H ₂Mixture) under carry out.Calcination time can be several minutes to several hours, and reduced with temperature usually.The source of the basal component of useful poly-metal deoxide active composition IV for for those compounds of oxide compound and/or can by at least in the presence of oxygen heating change into those compounds of oxide compound.

Remove the oxidation beyond the region of objective existence, useful initial compounds comprises that especially halogenide, nitrate, formate, oxalate, Citrate trianion, acetate, carbonate, amine complex, ammonium salt and/or oxyhydroxide (decompose and/or can decompose to obtain compound such as the NH with gas form release in the latter's one calcining at the latest ₄OH, (NH ₄) ₂CO ₃, NH ₄NO ₃, NH ₄CHO ₂, CH ₃COOH, NH ₄CH ₃CO ₂And/or ammonium oxalate can additionally mix in the close drying composite).

The initial compounds of preparation poly-metal deoxide active composition IV can mix closely with dry form or wet form.When they mixed with dry form, initial compounds suitably used as fine-powder and is mixing and choosing compacting wantonly and stand later calcining.Yet, preferably mix closely with wet form.Usually, initial compounds mixes mutually with the form of the aqueous solution and/or suspension.When starting raw material only is the basal component source of solubilized form, in described mixing process, obtain close especially dry mixture.The solvent for use preferably water.Subsequently with the aqueous composition drying that obtains, drying process preferably under 100-150 ℃ temperature out by the aqueous mixture spraying drying is carried out.

The poly-metal deoxide active composition of general formula I V can or be molded into certain catalyzer geometric format with powder type and be used for " propylene-propenal (if with suitable vinylformic acid) " step, and moulding can in the end calcine before or carry out later on.For example, the catalyzer of load can be by not being pressed into required catalyzer geometrical shape (for example by compressing tablet or extrude), if suitable adding auxiliary agent such as graphite or stearic acid are as lubricant and/or shaping assistant and toughener such as glass micro-fibers, asbestos, silicon carbide or potassium titanate and by active composition or its not calcining and/or the preparation of part incinerating precursor composition of powder type.Replace graphite, also can use the hexagon boron nitride as the auxiliary agent in the moulding, as 2,005 037 678 recommendations of DE-A10.The not supported catalyst geometrical shape that is fit to comprises that external diameter and length are solid cylinder or the hollow cylinder of 2-10mm.Under the situation of hollow cylinder, wall thickness is that 1-3mm is favourable.Certainly, supported catalyst can not have the spheroid geometrical shape yet, and spherical diameter can be 2-10mm.

Especially under the situation of supported catalyst not, particularly advantageous hollow cylinder geometrical dimension is 5mm * 3mm * 2mm (external diameter * length * internal diameter).

Certainly, still to calcine and/or the powdered activated composition of part incinerating or its powder precursor composition also can be by being applied on the preformed inert catalyst carrier and moulding.Coated carrier carries out in the rotatable container that is fit to usually to produce the catalyzer that applies, and is for example disclosed as DE-A 2 909 671, EP-A 293 859 or EP-A 714 700.Be coated carrier, powder composition to be administered is suitably got wet and after using for example by the warm air after drying.Be applied in powder composition coat-thickness on the carrier in the 10-1000 mu m range, in the preferred 50-500 mu m range, more preferably suitably select in the 150-250 mu m range.

The useful carrier material is conventional porous or non-porous aluminas, silicon-dioxide, thorium dioxide, zirconium dioxide, silicon carbide or silicate such as Magnesium Silicate q-agent or pure aluminium silicate.They for the inventive method based on goal response behavior inertia basically usually.Carrier can have rule or irregularly shaped, yet preferably has the carrier of the regular shape of tangible surfaceness, for example spheroid or hollow cylinder.Basically atresia, the shaggy ball type carrier of the carrier that is fit to for being made by talcum, its diameter are 1-10mm or to 8mm, preferred 4-5mm.Yet it is that 2-10mm and its external diameter are the right cylinder of 4-10mm that the carrier that is fit to also has length.Under the situation of the ring that is fit to according to the present invention as carrier, wall thickness also is 1-4mm usually.The length of annular carrier preferably used according to the invention is 2-6mm, and external diameter is 4-8mm, and wall thickness is 1-2mm.It is the ring of 7mm * 3mm * 4mm (external diameter * length * internal diameter) that the carrier that is fit to according to the present invention especially also has geometrical dimension.Certainly, the fineness of waiting to be applied over the catalytic activity oxide composition on the carrier surface is adjusted to required coat-thickness (referring to EP-A 714 700).

The poly-metal deoxide active composition that is ready to use in the step from the propylene to the propenal also is the composition of general formula V:

[Y ¹ _a’Y ² _b’O _x’] _p[Y ³ _c’Y ⁴ _d’Y ⁵ _e’Y ⁶ _f’Y ⁷ _g’Y ² _h’O _y’] _q(V)

Wherein variable is defined as follows separately:

Y ¹=only be bismuth or bismuth and elemental tellurium, antimony, tin and copper one of at least,

Y ²=molybdenum or tungsten, or molybdenum and tungsten,

Y ³=basic metal, thallium and/or samarium,

Y ⁴=alkaline-earth metal, nickel, cobalt, copper, manganese, zinc, tin, cadmium and/or mercury,

Y ⁵=iron or iron and elemental chromium and cerium one of at least,

Y ⁶=phosphorus, arsenic, boron and/or antimony,

Y ⁷=rare earth metal, titanium, zirconium, niobium, tantalum, rhenium, ruthenium, rhodium, silver, gold, aluminium, gallium, indium, silicon, germanium, lead, thorium and/or uranium,

A '=0.01 is to 8,

B '=0.1 is to 30,

C '=0 is to 4,

D '=0 is to 20,

E '=＞0 is to 20,

F '=0 is to 6,

G '=0 is to 15,

H '=8 are to 16,

X ', y '=by the valency of the element outside the deoxygenation among the V and the number of frequency decision,

P, q=p/q be than being the number of 0.1-10,

It comprises chemical composition Y ¹ _a' Y ² _b' O _x' 3D region, owing to they different compositions with their place environment, this zone and their place environment are demarcated, and its maximum diameter (passing regional center and connecting zone surface (interface) the longest last straight line at 2) is 1nm to 100 μ m, usually is 10-500nm or 1 μ m-50 or 25 μ m.

Particularly advantageous many metal composites V is Y wherein according to the present invention ¹Only be those of bismuth.

In these, those of preferred formula VI again:

[Bi _a”Z ² _b”O _x”] _p”[Z ² ₁₂Z ³ _c”Z ⁴ _d”Fe _e”Z ⁵ _f”Z ⁶ _g”Z ⁷ _h”O _y”] _q” (VI)

Wherein variable is defined as follows separately:

Z ²=molybdenum or tungsten, or molybdenum and tungsten,

Z ³=nickel and/or cobalt,

Z ⁴=thallium, basic metal and/or alkaline-earth metal,

Z ⁵=phosphorus, arsenic, boron, antimony, tin, cerium and/or lead,

Z ⁶=silicon, aluminium, titanium and/or zirconium,

Z ⁷=copper, silver and/or golden,

A "=0.1 to 1,

B "=0.2 to 2,

C "=3 to 10,

D "=0.02 to 2,

E "=0.01 to 5, it is preferred 0.1 to 3,

F "=0 to 5,

G "=0 to 10,

H "=0 to 1,

X ", y "=by the number of the valency of the element outside the deoxygenation among the VI and frequency decision, p ", q "=p "/q " than being 0.1 to 5, preferred 0.5 to 2 number, very particularly preferably Z wherein ² _{B "}=(tungsten) _{B "}And Z ² ₁₂=(molybdenum) ₁₂Those compositions VI.

[the Y of the multimetal oxide compositions V (multimetal oxide compositions VI) that the present invention is fit in the multimetal oxide compositions V (multimetal oxide compositions VI) that the present invention is fit to also advantageously ¹ _{A '}Y ² _{B '}O _{X '}] _p([Bi _{A "}Z ² _{B "}O _{X "}] _{P "}) at least 25 moles of % (preferably at least 50 moles of %, more preferably at least 100 moles of %) of total content be chemical composition Y ¹ _{A '}Y ² _{B '}O _{X '}[Bi _{A "}Z ² _{B "}O _{X "}] form of 3D region, because they and the different compositions of their place environment, this zone and their place environment description, and its maximum diameter is 1nm to 100 μ m.

About moulding, the argumentation of making about multimetal oxide compositions IV catalyzer is applicable to multimetal oxide compositions V catalyzer.

The preparation example of poly-metal deoxide active composition V is as being described among EP-A 575 897 and the DE-A 198 55 913.

More than the inert support material of Tui Jianing is also especially as dilution and/or demarcate to be fit to the inert material of stationary catalyst bed, or as the elementary bed of protection they and/or heated air mixture.

For second step (second step of reaction), the propenal heterogeneous catalyzed gas phase partial oxidation is become vinylformic acid, the useful activity composition of required catalyzer is as already described in principle for comprising all multimetal oxide compositions of Mo and V, for example those of DE-A 100 46 928.

It is most, for example among those be contained in general formulas VII of DE-A 198 15 281:

Mo ₁₂V _aX ¹ _bX ² _cX ³ _dX ⁴ _eX ⁵ _fX ⁶ _gO _n (VII)

Wherein variable is defined as follows separately:

X ¹=W, Nb, Ta, Cr and/or Ce,

X ²=Cu, Ni, Co, Fe, Mn and/or Zn,

X ³=Sb and/or Bi,

X ⁴=one or more basic metal,

X ⁵=one or more alkaline-earth metal,

X ⁶=Si, Al, Ti and/or Zr,

A=1 to 6,

B=0.2 to 4,

C=0.5 to 18,

D=0 to 40,

E=0 to 2,

F=0 to 4,

G=0 to 40 and

N=is by the valency of the element outside the deoxygenation among the VII and the number of frequency decision.

In active poly-metal deoxide VII, the preferred embodiment of the invention is those of general formula VII that are contained in following variable-definition:

X ¹=W, Nb and/or Cr,

X ²=Cu, Ni, Co and/or Fe,

X ³＝Sb，

X ⁴=Na and/or K,

X ⁵=Ca, Sr and/or Ba,

X ⁶=Si, Al and/or Ti,

A=1.5 to 5,

B=0.5 to 2,

C=0.5 to 3,

D=0 to 2,

E=0 to 0.2,

F=0 to 1 and

Yet, those that the particularly preferred poly-metal deoxide VII of the present invention is general formula VIII:

Mo ₁₂V _a’Y ¹ _b’Y ² _c’Y ⁵ _f’Y ⁶ _g’O _n’(VIII)

Wherein

Y ¹=W and/or Nb,

Y ²=Cu and/or Ni,

Y ⁵=Ca and/or Sr,

Y ⁶=Si and/or Al,

A '=2 are to 4,

B '=1 is to 1.5,

C '=1 is to 3,

F '=0 is to 0.5

G '=0 is to 8 Hes

N '=by the valency of the element outside the deoxygenation among the VIII and the number of frequency decision.

The poly-metal deoxide active composition (VII) that the present invention is fit to can obtain in a manner known way, and for example DE-A 43 35 973 or EP-A 714 700 are disclosed.

In principle, be suitable for the poly-metal deoxide active composition of " propenal → vinylformic acid " step, especially those of general formula VII can be with plain mode by being obtained having stoichiometric very close corresponding to them by its basal component source that is fit to, preferred drying composite in small, broken bits and 350-600 ℃ down calcining it and prepare.Calcining can be under rare gas element or under oxidizing atmosphere such as air (mixture of rare gas element and oxygen), and at reducing atmosphere (for example rare gas element and reducing gas such as H ₂, NH ₃, CO, methane and/or the mixture of propenal or the reducing gas of being mentioned self) under carry out.Calcination time can for example be several minutes extremely several hours, and reduces with temperature usually.The source of the basal component of useful poly-metal deoxide active composition VII comprise for those compounds of oxide compound and/or can by at least in the presence of oxygen heating change into those compounds of oxide compound.

The initial compounds of preparation poly-metal deoxide active composition VII can mix closely with dry form or wet form.When they mix with dry form, if initial compounds suitably uses with the fine-powder form and stands calcining later in mixing and suitable compacting.Yet, preferably mix closely with wet form.

This mixes mutually with the form of the aqueous solution and/or suspension by initial compounds usually and carries out.When starting raw material only is the basal component source of solubilized form, in described mixing process, obtain close especially dry mixture.The solvent for use preferably water.Subsequently with the aqueous composition drying that obtains, drying process preferably under 100-150 ℃ temperature out by the aqueous mixture spraying drying is carried out.

The multimetal oxide compositions, especially those of general formula VII that produce can or be molded into certain catalyzer geometric format with powder type and be used for acrolein oxidation, and moulding can in the end calcine before or carry out later on.For example, the catalyzer of load can be by not being pressed into required catalyzer geometrical shape (for example by compressing tablet or extrude), if suitable adding auxiliary agent such as graphite or stearic acid are as lubricant and/or shaping assistant and toughener such as glass microfiber, asbestos, silicon carbide or potassium titanate and by the active composition of powder type or its not calcined precursors preparation of compositions.The example of the not supported catalyst geometrical shape that is fit to comprises that external diameter and length are solid cylinder or the hollow cylinder of 2-10mm.Under the situation of hollow cylinder, wall thickness is that 1-3mm is fit to.Certainly, supported catalyst can not have the spheroid geometrical shape yet, and spherical diameter can be 2-10mm (for example 8.2mm or 5.1mm) in this case.

Certainly, still want powdered activated composition of incinerating or its powder precursor composition also can be and moulding by being applied on the preformed inert catalyst carrier.Coated carrier carries out in the rotatable container that is fit to usually with the catalyzer that preparation applies, and is for example disclosed as DE-A 2 909 671, EP-A 293 859 or EP-A 714 700.

Be coated carrier, powder composition to be administered is suitably got wet and after using for example by the warm air after drying.Be applied in powder composition coating thickness on the carrier in the 10-1000 mu m range, in the preferred 50-500 mu m range, more preferably suitably select in the 150-250 mu m range.

The useful carrier material is conventional porous or non-porous aluminas, silicon-dioxide, thorium dioxide, zirconium dioxide, silicon carbide or silicate such as Magnesium Silicate q-agent or pure aluminium silicate.Carrier can have rule or irregularly shaped, yet preferably has the carrier of the regular shape of tangible surfaceness, for example has the spheroid or the hollow cylinder of coarse sands layer.The carrier that is fit to comprises the atresia basically that is made by talcum, shaggy ball type carrier, and its diameter is 1-10mm or to 8mm, preferred 4-5mm.In other words, the ball type carrier geometrical shape of Shi Heing can have the diameter of 8.2mm or 5.1mm.Yet the carrier that is fit to comprises that also length is that 2-10mm and its external diameter are the right cylinder of 4-10mm.Under the situation of ring as carrier, wall thickness also is 1-4mm usually.The length of annular carrier preferred to be used is 2-6mm, and external diameter is 4-8mm, and wall thickness is 1-2mm.It is the ring of 7mm * 3mm * 4mm (external diameter * length * internal diameter) that the carrier that is fit to especially also has geometrical dimension.Certainly, the fineness of waiting to be applied over the catalytic activity oxide composition on the carrier surface is adjusted to required coat-thickness (referring to EP-A 714 700).

The favourable poly-metal deoxide active composition that is ready to use in " propenal → vinylformic acid " step also is the composition of general formula I X:

[D] _p[E] _q (IX)

Wherein variable is defined as follows separately:

D＝Mo ₁₂V _a”Z ¹ _b”Z ² _c”Z ³ _d”Z ⁴ _e”Z ⁵ _f“Z ⁶ _g”O _x”，

E＝Z ⁷ ₁₂Cu _h”H _i”O _y”，

Z ¹=W, Nb, Ta, Cr and/or Ce,

Z ²=Cu, Ni, Co, Fe, Mn and/or Zn,

Z ³=Sb and/or Bi,

Z ⁴=Li, Na, K, Rb, Cs and/or H,

Z ⁵=Mg, Ca, Sr and/or Ba,

Z ⁶=Si, Al, Ti and/or Zr,

Z ⁷=Mo, W, V, Nb and/or Ta, preferred Mo and/or W,

a”＝1-8，

b”＝0.2-5，

c”＝0-23，

d”＝0-50，

e”＝0-2，

f”＝0-5，

g”＝0-50，

h”＝4-30，

I "=0-20 and

X ", y "=be different among the IX valency of element of oxygen and number that frequency is determined and

P, q=are different from 0 number, wherein p/q=160: 1-1: 1,

And it can be by respectively with the multimetal oxide compositions E (starting composition 1) of form in small, broken bits:

Z ⁷ ₁₂Cu _h”H _i”O _y” (E)

Prefabricated and subsequently with ready-formed solid starting composition 1 with required p: q than doping element Mo, V, Z ¹, Z ², Z ³, Z ⁴, Z ⁵, Z ⁶In the aqueous solution, aqeous suspension or the dry mixture in small, broken bits (starting composition 2) in source, the latter comprises above-mentioned element with stoichiometry D:

Mo ₁₂V _a”Z ¹ _b”Z ² _c”Z ³ _d”Z ⁴ _e”Z ⁵ _f”Z ⁶ _g” (D)

With producible aqueous mixture drying, and before drying or the dried precursor composition that will produce afterwards 250-600 ℃ down calcining to obtain required catalyzer geometrical shape.

Preferably wherein prefabricated solid starting composition 1 mixes the multimetal oxide compositions IX in the moisture starting composition 2 under＜70 ℃.The detailed description of preparation multimetal oxide compositions VI catalyzer for example is contained among EP-A 668 104, DE-A 197 36 105, DE-A 100 46 928, DE-A 197 40 493 and the DE-A 195 28 646.

About moulding, the argumentation of making about multimetal oxide compositions VII catalyzer is applicable to multimetal oxide compositions IX catalyzer.

The multi-metal-oxide catalyst that significantly is suitable for " propenal → vinylformic acid " step also has those of DE-A198 15 281, especially has those of poly-metal deoxide active composition of general formula I in this document.

Advantageously, the catalyst rings of load is not used for the step from the propylene to the propenal, and the catalyst rings of coating is used for from propenal to acrylic acid step.

The available described catalyzer that carries out that the propylene partial oxygen changes into propenal (if with suitable vinylformic acid) in the inventive method for example carries out in single district multi-catalyst pipe fixed-bed reactor, as described in DE-A 4,431 957.In this case, from the reactor top, reaction gas mixtures and thermal barrier (heat exchange medium) can and flow or the adverse current conduction.

Reaction pressure is generally 1-3 crust, the gross space speed on the stationary catalyst bed of (initial) reaction gas mixtures 2 preferred 1500 to 4000 or 6000 l (STP)/lh or bigger.Propylene load (the propylene space-time speed on the stationary catalyst bed) is generally 90-200 l (STP)/lh or to 300 l (STP)/lh or bigger.According to the present invention, preferred especially 135 l (STP)/lh above or 〉=140 l (STP)/lh, or 〉=150 l (STP)/lh, or 〉=the propylene load of 160 l (STP)/lh, this be since initial action gaseous mixture of the present invention because the existence of unconverted propane produces favourable focus behavior (above-mentioned all be suitable for and regardless of the concrete selection of fixed-bed reactor).

The charging gaseous mixture preferably flow to single district multi-catalyst pipe fixed-bed reactor from above.Used heat exchange medium suitably is a salt-melting, and it is preferably by 60 weight % saltpetre (KNO ₃) and 40 weight % Sodium Nitrite (NaNO ₂) form, or by 53 weight % saltpetre (KNO ₃), 40 weight % Sodium Nitrite (NaNO ₂) and 7 weight % SODIUMNITRATE (NaNO ₃) form.

From the reactor top, as already described, salt-melting and reaction gas mixtures can and flow or the adverse current conduction.Salt-melting self preferably conducts around catalyst tube in the meander mode.

When flowing to catalyst tube from the top to the bottom, it is following with the catalyst tube catalyzer (for flowing to the top from the bottom, loading sequence is suitably opposite) of packing into from bottom to top that suitable is:

-at first, and to 40-80% or to the length of 60% catalyzer pipe range, the mixture of catalyzer or catalyzer and inert material only, the latter accounts for 30 weight % or the weight ratio of 20 weight % (portion C) at the most at the most based on mixture;

-thereafter, and to 20-50% or to the length of 40% catalyzer pipe range, the mixture of catalyzer or catalyzer and inert material only, the latter accounts for the weight ratio of 40 weight % (part B) at the most based on mixture;

-last, to the length of the total pipe range of 10-20%, inert material bed (part A), it preferably selects to make it to produce very little pressure drop.

Portion C is preferably undiluted.

When catalyst system therefor is the Research Disclosure No.497012 on August 29th, 2005, or the embodiment 1 of DE-A 100 46 957, or those and the used inert material of the embodiment 3 of DE-A 100 46 957 be geometrical dimension when being the talcum ring of 7mm * 7mm * 4mm (external diameter * length * internal diameter), and it is especially suitable that above-mentioned charging changes scheme.About salt temperature, use the argumentation of DE-A 4 431 957.

Yet, the also available described catalyzer of carrying out that propylene partial oxygen of the present invention changes into propenal (if with suitable vinylformic acid) for example carries out in two district's multi-catalyst fixed-bed reactor, as described in DE-A 19,910 506, DE-A 10 2,005 009 885, DE-A 10 2,004 032 129, DE-A 10 2,005 013039 and DE-A 10 2,005 009 891 and DE-A 10 2,005 010 111.(with very in the methods of the invention general) in the above two kinds of cases, the propylene conversion general value that one way realizes is 〉=90 moles of %, or 〉=95 moles of %, the selective value that propenal forms is 〉=90 moles of %.The present invention advantageously, propylene partial oxygen of the present invention changes into propenal or vinylformic acid or its mixture as described in the EP-A1 159 244, most preferably carries out as described in WO 04/,085 363 and WO 04/,085 362.

Document EP-A 1 159 244, WO 04/,085 363 and WO 04/,085 362 are considered to the integral part of this file.

In other words, the partial oxidation of propylene of the present invention can particularly advantageously carry out on the stationary catalyst bed of the propylene space-time speed with raising and two humidity provinces at least.

In this regard, for example with reference to EP-A 1 159 244 and WO 04/,085 362.

In the methods of the invention, being used for the common composition that the propylene partial oxygen changes into the initial action gaseous mixture of propenal can comprise:

5-9 volume % propylene,

8-18 volume % molecular oxygen,

6-30 (or to 35) volume % propane and

32-72 volume % dinitrogen.

Change under the situation of propenal in propylene two-stage partial oxygen, second step, promptly propenal moiety is oxidized to acrylic acid carrying out and can for example carries out in district's multi-catalyst pipe fixed-bed reactor as catalyzer as described in the usefulness as described in the DE-A 44 31 949.In this step of reaction, from the reactor top, reaction gas mixtures and thermal barrier can and spread leads.Usually, the invention described above propylene partial oxygen changes into the product gas mixture direct in principle (if after suitable cooling therebetween (this can for example carry out by the secondary air adding indirectly or directly)) of propenal, promptly do not have secondary component to remove and import second step of reaction, be i.e. in the propenal moiety oxidation.

Second step, the desired molecular oxygen of propenal moiety oxidation can be present in the initial action gaseous mixture that propylene partial oxygen of the present invention changes into propenal.Yet, it also can partially or completely directly add first step of reaction, be that propylene partial oxygen of the present invention changes into the product gas mixture in the propenal (this preferably carries out with the form of (secondary) air, but also can carry out with the form of the mixture of purity oxygen or rare gas element or oxygen).No matter program, this propenal moiety is oxidized to acrylic acid charging gaseous mixture (initial action gaseous mixture) and advantageously has following content:

4-8 volume % propenal,

2.25 or 4.5 to 9 volume % molecular oxygens,

6-30 volume % propane,

32-72 volume % dinitrogen,

5-15 volume % steam.

Above-mentioned initial action gaseous mixture preferably has following content:

5-8 volume % propenal,

2.75 or 5.5 to 9 volume % molecular oxygens,

10-25 volume % propane,

40-70 volume % dinitrogen,

5-15 volume % steam.

Above-mentioned initial action gaseous mixture most preferably has following content:

5-8 volume % propenal (preferred 6-7 volume %),

3 or 6 to 9 volume % molecular oxygens,

10-20 volume % propane (preferred 10-16 volume %),

50-65 volume % dinitrogen,

7-13 volume % steam,

Wherein preferable range is used independently of each other, and advantageously realizes simultaneously.

With the same in first step of reaction (propylene → propenal), the reaction pressure of second step of reaction (propenal → vinylformic acid) also is generally 1-3 crust, the gross space speed of (initial) reaction gas mixtures on stationary catalyst bed preferred 1500 to 4000 or 6000 l (STP)/lh or bigger.Propenal load (the propenal space-time speed on the stationary catalyst bed) is generally 90-190 l (STP)/lh or to 290 l (STP)/lh or bigger.According to the present invention, preferred especially 135 l (STP)/lh above or 〉=140 l (STP)/lh, or 〉=150 l (STP)/lh, or 〉=the propenal load of 160 l (STP)/lh, this is to produce favourable focus effect because the present invention's initial action gaseous mixture to be used is same.

By stationary catalyst bed, acrolein conversion rate suitably is 〉=90 moles of % usually based on initial action gaseous mixture one way, and it is 〉=90 moles of % that the vinylformic acid of following forms selectivity.

The gaseous mixture that loads equally preferably flow to single district multi-catalyst pipe fixed-bed reactor from above.Used heat exchange medium also suitably is a salt-melting in second stage, and it is preferably by 60 weight % saltpetre (KNO ₃) and 40 weight % Sodium Nitrite (NaNO ₂) form, or by 53 weight % saltpetre (KNO ₃), 40 weight % Sodium Nitrite (NaNO ₂) and 7 weight % SODIUMNITRATE (NaNO ₃) form.From the reactor top, as already described, salt-melting and reaction gas mixtures can and flow or the adverse current conduction.Salt-melting self preferably conducts around catalyst tube in the meander mode.

When flowing to catalyst tube from the top to the bottom, it is following with the catalyst tube catalyzer of packing into from bottom to top that suitable is:

-at first, and to 50-80% or to the length of 70% catalyzer pipe range, the mixture of catalyzer or catalyzer and inert material only, the latter is based on the weight ratio (portion C) of mixture (or at the most 20) the weight % that accounts at the most 30;

-thereafter, and to the length of 20-40% catalyzer pipe range, the mixture of catalyzer or catalyzer and inert material only, the latter accounts for 50 weight % or the weight ratio of 40 weight % (part B) at the most at the most based on mixture; With

-last, to the length of the total pipe range of 5-20%, inert material bed (part A), it preferably selects to make it to produce very little pressure drop.

Portion C is preferably undiluted.As the very general situation that becomes vinylformic acid (the especially high steam content of high propenal load and charging gaseous mixture on the stationary catalyst bed) for the propenal heterogeneous catalyzed gas phase partial oxidation, part B also can be made of (in order to make hot(test)-spot temperature and hot(test)-spot temperature susceptibility minimum) two kinds of catalyst dilution things in succession.From bottom to top, at first use at the most 30 (or 20) weight % inert material and using subsequently＞20 weight % to 50 or to 40 weight % rare gas elementes.Portion C is preferably undiluted then.

For by the bottom to overhead stream to catalyst tube, catalyst tube charging is suitably opposite.

When catalyst system therefor is that those and the used inert material of those or DE-A 19,815 281 of the preparation embodiment 5 of DE-A 100 46 928 is geometrical dimension when being the lardite ring of 7mm * 7mm * 4mm or 7mm * 7mm * 3mm (external diameter * height * internal diameter), it is especially suitable that above-mentioned charging changes scheme.About salt temperature, use the argumentation of DE-A 443 19 49.It is usually so that the acrolein conversion rate that realizes in the one way is generally 〉=90 moles of %, or 〉=95 moles of %, or 〉=mode of 99 moles of % selects.

Yet propenal moiety is oxidized to and acrylic acidly carries out also available described catalyzer and for example carry out in DE-199 10 508 described two district's multi-catalyst pipe fixed-bed reactor.For acrolein conversion rate, use above-mentioned argumentation.Therein as mentioned above the propenal moiety oxidation under the situation of two-stage propylene oxidation in two district's multi-catalyst pipe fixed-bed reactor becomes acrylic acid subordinate phase, carrying out, charging gaseous mixture (initial action gaseous mixture) will be suitably by use for the product gas mixture of the partial oxidation of first step directly (if suitable connect betwixt or direct intercooling after (for example by infeeding secondary air)) obtain (describing) as top.The required oxygen of propenal moiety oxidation preferably adds with the form (if suitable also with the form of pure molecular oxygen or the form of molecular oxygen and noble gas mixtures) of air, and for example directly adds in the product gas mixture of first step (propylene → propenal) of two-stage partial oxidation.Yet as described in, it also can be present in the initial action gaseous mixture of first step of reaction.

Propylene two-stage partial oxygen in the product gas mixture that directly uses first partial oxidation step is in addition packed second partial oxidation step into changes in the vinylformic acid, two one district's multi-catalyst pipe fixed-bed reactor are (under the high reactant space-time speed of catalyst bed, as very general situation, from tubular reactor top, the counter-flow pattern between preferred reactant gas and the salt bath (thermal barrier)) or two two district's multi-catalyst pipe fixed-bed reactor be connected in series usually.It is also possible to mix series connection (otherwise a district/two districts or).

If the configurable suitable side cooler that comprises the inert bed that to bring into play filter function between reactor.The salt temperature that propylene two-stage partial oxygen changes into the multi-catalyst pipe reactor of acrylic acid first step is generally 300-400 ℃.Propylene two-stage partial oxygen changes into acrylic acid second step, and the salt temperature that propenal moiety is oxidized to acrylic acid multi-catalyst pipe reactor is generally 200-350 ℃.In addition, heat exchange medium (preferably salt melt) usually by relevant multi-catalyst pipe fixed-bed reactor so that the difference between their input and the output temperature is generally≤5 ℃ amount conduction.As already mentioned, the propylene partial oxygen changes into acrylic acid two steps also can carry out through once feeding in a reactor, as described in DE-A 101 21 592.

The a part of initial action gaseous mixture that also should mention first step (" propylene → propenal ") once more can be the entrap bubble from partial oxidation.

As illustrating, this is remaining after comprising molecular oxygen and take out (propenal and/or vinylformic acid take out) at target product from the product gas mixture of partial oxidation, and if can part be recycled to the propylene partial oxygen as inert dilution gas and change into gas in propenal and/or acrylic acid first and/or suitable second step.

Yet, comprise this entrap bubble of propane, molecular oxygen and any unconverted propylene will be preferably advantageously only initial materials flow 2 is recycled to heterogeneous catalysis dehydrogenating propane among the reaction zone A as gaseous state according to the present invention.

In a word, wherein the tube bundle reactor that suitably changes along each catalyst tube with finishing of first reactions steps of catalyst charge (this in single reaction vessel two-stage propylene partial oxidation for example by EP-A911 313, EP-A 979 813, EP-A 990 636 and DE-A 28 30 765 instructions) forms the simplest form of carrying out that is changed into two oxidation stages of acrylic acid two steps by the propylene partial oxygen.If suitable, blocked by the inert material bed with the catalyst loading catalyst tube.

Yet, preferably carry out two oxidation stages with two forms of restraining systems that are connected in series.These are configurable in a reactor, form by (with suitably being easy to stand) the inert material bed that is not configured in the catalyst tube to the transfer of another tube bank from a tube bank in this case.When catalyst tube usually by thermal barrier when flowing, this does not arrive the inert bed of configuration as mentioned above.Advantageously, therefore configuration spatially independently in the reactor of two catalyzer tube bank.Usually side cooler is configured between two pipe reactions to be reduced in any propenal afterfire of carrying out in the product gas mixture that leaves first oxidation zone.Temperature of reaction in first step of reaction (propylene → propenal) is generally 300-450 ℃, preferred 320-390 ℃.Temperature of reaction in second step of reaction (propenal → vinylformic acid) is generally 200-370 ℃, usually is 220-330 ℃.Reaction pressure in two oxidation zones suitably is the 0.5-5 crust, advantageously the 1-3 crust.(l (STP)/lh) usually is 1500-2500 l (STP)/lh or to 4000 l (STP)/lh to speed during reactant gases empty on the oxide catalyst in two step of reaction.Speed can be 100 to 200 or 300 or more l (STP)/lh during propylene empty.

In principle, in the inventive method two oxidation stages can be for example as configuration as described in DE-A 198 37 517, DE-A 199 10 506, DE-A 199 10 508 and the DE-A 198 37 519.

In two step of reaction, the excessive molecular oxygen of the amount that needs with respect to the reactive chemistry First Astronautic Research Institute for Measurement and Test has favourable influence to the kinetics and the catalyst life of special gas-phase partial oxidation.

In principle, also can realize in following single tubular reactor according to the present invention the heterogeneous gas-phase partial oxidation of propylene is become vinylformic acid.Two reactions steps are carried out in the oxidation reactor of poly-metal deoxide that one or more its active compositions are housed is containing element Mo, Fe and Bi and catalyst for reaction that can two reactions steps of catalysis.This catalyst charge certainly can be along reaction coordinate continuously or flip-flop.Certainly, change in the acrylic acid embodiment in propylene two-stage partial oxygen of the present invention, before it imports second oxidation stage into, from then on partly or entirely remove in the product gas mixture if necessary as by product and in first oxidation stage, form and be present in carbonic acid gas and steam in the product gas mixture that leaves first oxidation stage with two oxidation stage forms being connected in series.This program of removing preferably is provided not provide according to the present invention.

As described in, outside the useful source deacration (preferably) of the middle oxygen charging of carrying out between two oxidation stages, for pure molecular oxygen or with rare gas element such as CO ₂, CO, rare gas, N ₂And/or the molecular oxygen of stable hydrocarbon dilution.

In the methods of the invention, for example freezing air is metered in the product gas mixture in first partial oxidation stage also and can further produces its cooling by direct route in the past at it as the component of the initial action gaseous mixture in second partial oxidation stage.

According to the present invention advantageously, propenal moiety is oxidized to vinylformic acid as described in the EP-A 1,159 246, most preferably carries out as described in WO 04/,085 365 and WO 04/,085 370.Yet, the present invention preferably uses the initial action gaseous mixture as the initial action gaseous mixture that comprises propenal, it changes into the product gas mixture of propenal for propylene fs partial oxygen of the present invention, and to replenish under every kind of situation of ratio of the molecular oxygen that makes in the initial action gaseous mixture that produces and propenal with enough secondary airs be 0.5-1.5 if it is suitable.Document EP-A 1 159 246, WO 04,/08 536 and WO 04/,085 370 are considered to the integral part of file for this reason.

In other words, propenal moiety of the present invention is oxidized to vinylformic acid and can advantageously carries out having on the stationary catalyst bed of at least two humidity provinces with the propenal space-time speed that improves.

In a word, propylene two-stage partial oxygen changes into vinylformic acid and will preferably carry out as described in EP-A 1 159 248 or WO04/085 367 or WO 04/,085 369.

Under preparation propenal and/or acrylic acid situation, the product gas mixture materials flow B that leaves the pending partial oxidation of the present invention (after first and/or second step of reaction) comprises the mixture of target product propenal or vinylformic acid or itself and propenal basically, unconverted molecular oxygen is (from the life-span of catalyst system therefor, when oxygen level in the product gas mixture in two partial oxidation stages favourable during still for 1.5-4 volume % at least), propane, unconverted propylene, dinitrogen, formed and/or be used as the steam of diluent gas as by product, formed and/or be used as the carbonoxide of diluent gas as by product, with a small amount of other lower aldehyde, lower alkanoic acid (acetate for example, formic acid and propionic acid) and maleic anhydride, phenyl aldehyde, aromatic carboxylic acid and aromatic carboxylic acid's acid anhydride (for example Tetra hydro Phthalic anhydride and phenylformic acid) also have hydrocarbon such as C in some cases ₄Hydrocarbon (for example butene-1 and other possible butylene) and other inert dilution gas.

Target product can be in the B of disengaging zone from product gas mixture B, take out in a manner known way (if for example by acrylic acid partially or completely and suitable fractional condensation, or in water or in the high boiling point hydrophobic organic solvent, absorb, or in water or in the aqueous solution of lower carboxylic acid more, absorb and aftertreatment condensation product and/or absorbate subsequently by propenal by vinylformic acid; According to the present invention, product gas mixture B is with preferred fractional condensation; For example referring to EP-A 1 388 533, EP-A 1,388 532, DE-A 102 35 847, EP-A 7 92 867, WO 98,/01 415, EP-A 1 015 411, EP-A 1 015 410, WO 99,/50 219, WO 00,/53 560, WO 02,/09 839, DE-A102 35 847, WO 03/,041 833, DE-A 102 23 058, DE-A 102 43 625, DE-A103 36 386, EP-A 854 129, US-A 4 317 926, DE-A 198 37 520, DE-A196 06 877, DE-A 190 50 1325, DE-A 102 47 240, DE-A 197 40 253, EP-A695 736, EP-A 982 287, EP-A 1 041 062, EP-A 117 146, DE-A 43 08 087, DE-A 43 35 172, DE-A 44 36 243, DE-A 199 24 532, DE-A 103 32 758 and DE-A 199 24 533).Vinylformic acid takes out also can be as carrying out among EP-A 982 287, EP-A 982 289, DE-A103 36 386, DE-A 101 15 277, DE-A 196 06 877, DE-A 197 40 252, DE-A1 96 27 847, EP-A 920 408, EP-A1068 174, EP-A 1 066 239, EP-A1 066 240, WO 00,/53 560, WO 00,/53 561, DE-A 100 53 086 and the EP-A 982 288.Preferably as described in Fig. 7 of WO/0 196 271 or as taking-up as described in DE-A 10 2,004 032 129 and its equal patent.Favourable removing method also has document WO 04/,063 138, WO04/035 514, DE-A 102 43 625 and DE-A 102 35 847 described methods.The crude acrylic acid that obtains like this can be for example as further processing as described in document WO 01,/77 056, WO 03/,041 832, WO 02/,055 469, WO 03/,078 378 and the WO 03/,041 833.

The common trait of above separation method for (mentioning) as beginning be included in basically standard pressure (1 crust) down its boiling point usually remain in the top of special knockout tower for the entrap bubble materials flow of those components (promptly being difficult to condensation or evaporable component) of≤-30 ℃ product gas mixture B, knockout tower comprises and separates internals and directly and/or indirectly after the cooling product gas mixture B is infeeded it than lower curtate carrying out it usually.

Knockout tower than lower curtate in, in condensation mutually, obtain usually product gas mixture B than the non-volatility component, comprise specific target product.

The entrap bubble component is mainly propane and unconverted any propylene, molecular oxygen and be usually used in other inert dilution gas such as nitrogen and carbonic acid gas in the partial oxidation in partial oxidation.Depend on used separation method, steam can be only with trace or so that 20 volume % or more amount are present in the entrap bubble at the most.

According to the present invention, at least a portion (the preferred all amounts that comprise propane, molecular oxygen and any unconverted propylene, yet, if half of suitable only these whole amounts or 2/3rds, or 3/4ths), (preferably having entrap bubble forms), initial materials flow 2 was recycled to reaction zone A to this main entrap bubble as gaseous state.Yet the part entrap bubble also can be recycled to one or two stage of partial oxidation and/or incinerate with generate energy.

Certainly, also so file and EP-A 117 146, US-A 3 161 670, DE-A 33 13 573 and DE-A 103 16 039 are described, entrap bubble before initial materials flow 2 is used as gaseous state from entrap bubble part or especially whole components except that removal propane, propylene and molecular oxygen.

In the aftertreatment (for taking out target product) of condensation phase,, can produce other entrap bubbles because it is attempted to make the unconverted propane of whole amounts that is present among the product gas mixture B to be recycled to reaction zone A usually and in target is taken out it is reclaimed.Although they still comprise propane and propylene in some cases usually, they usually no longer comprise any molecular oxygen.Usually, they combine with main entrap bubble that initial materials flow 2 is recycled to reaction zone A as gaseous state to obtain total residual gas.Yet, also can use this other entrap bubbles separately or make them be recycled to reaction zone A.

Therefore the whole recirculation of preferred residue total residual gas make propane change into vinylformic acid and/or propenal continuously in operate continuously.

In this context, the operator scheme of the present invention of importantly described circulation and reaction zone A makes and can realize that wherein fresh propane becomes propylene with hundred-percent selective conversion basically.

The advantage of this program all exists under lower (≤30 moles of %) and high (〉=30 moles of %) conversion rate of dehydrogenation (passing through reaction zone A based on one way).Usually under situation of the present invention, when hydrogen richness among the reaction gas mixtures input materials flow A for favourable during stoichiometric ratio (burning into water) at least based on oxygen with the amount of the oxygen that wherein exists.

Here should emphasize once more also that vinylformic acid preferably takes out by this way from the product gas mixture B that the present invention obtains: if will be suitable by direct or indirect cooling in advance refrigerative product gas mixture B comprising the separation inner member, has fractional condensation in the tower of lateral tap of crude acrylic acid, rise (for example to itself), and/or absorb by water and/or the aqueous solution, for example as described in WO 04/035514 and the DE-A 102 43 625.The crude acrylic acid that takes out preferably stands suspension crystallization subsequently, and the vinylformic acid suspension crystal that forms preferably takes out from the residue mother liquor by washing tower.Advantageously, the vinylformic acid crystalline melt of used washings in washing tower, taking out in advance.In addition, washing tower is preferably to have to force and carries the sort of of bed of crystals.More preferably waterpower or machine washing tower.For detail, can follow the description of WO 01,/77 056, WO 03/,041 832 and WO 03/,041 833.In other words, preferably remain mother liquor and be recycled to fractional condensation (also referring to EP-A 1 015 410).Secondary component is discharged conduct removing materials flow below the lateral tap of crude acrylic acid usually.

Only use a crystallisation stage, therefore can obtain the vinylformic acid of purity for 〉=99.8 weight %, it significantly is suitable for preparing the super-absorbent based on sodium polyacrylate.

Embodiment and comparative example (structured material: 1.4841 type stainless steels)

I. the operator scheme of the universal test device of reaction zone A and it

Heterogeneous catalysis part dehydrogenating propane carries out in the column plate annular-pipe reactor of Fig. 4, relates to following symbol of numeral among the figure.

Vertical tube type reactor (11) (internal diameter: 80mm) be provided with thermal fluid heater (9) (can the make tubular reactor basically adiabatic) parcel of thermal isolation (10).The temperature of thermal fluid heater is 500 ℃.In the center configuration of tubular reactor the sleeve pipe that comprises the Continuous Heat element and the telescopic pipe core (external diameter: 20mm) of classification thermoelectric converter are arranged.In addition, it comprises the pipeline that leads to tubular reactor, and by this pipeline, the reactant gases sample can take out from tubular reactor, and pipeline leads to tubular reactor, and air can inject tubular reactor by its.

Tubular reactor comprises three column plates (5,6,7), and it is by three that are placed on online 1: 1 bed volume of the Stainless Steel Wire ratio identical inert material bed (height of bed: 100mm; Diameter is the talcum ball of 1.5-2.5mm) and dehydrogenation catalyst and talcum ball (the diameter: (height of bed: 165mm) (on flow direction, arrange) composition with specified order of mixture 1.5-2.5mm).Therefore, total height of bed is 265mm under every kind of situation.

Dehydrogenation catalyst is the Pt/Sn alloy, and it promotes also with Pt with oxidised form with element Cs, K and La _0.3Sn _0.6La _3.0Cs _0.5K _0.2(ZrO ₂) _88.3(SiO ₂) _7.1Element chemistry metering (mass ratio that comprises carrier) be applied over ZrO ₂SiO ₂((Gauss respectively in the 3-12mm scope for mean length for mixed oxide carrier extrudate, the about 6mm of maximum value): 6mm, diameter: outside surface 2mm) and internal surface (catalyst precursor preparation and the embodiment 4 that activates into active catalyst such as DE-A 10219879).

Hybrid element is installed in each catalyzer column plate upstream.

Leave the identical composition of product gas mixture A separated into two parts of last column plate (12).Half (2) (product gas mixture A stream 1) is recycled to dehydrogenation as the component of reaction gas mixtures input materials flow A (4).Second half (1) (product gas mixture A stream 2) is derived dehydrogenation zone (reaction zone A).

Reaction gas mixtures input materials flow A (4) is made up of initial materials flow 1 (2) of gaseous state and the gaseous state starting mixt materials flow (3) that comprises steam, the entrap bubble from partial oxidation, fresh propane and molecular hydrogen.This starting mixt materials flow (3) is the jet that starts that separates the squirt pump of described product gas mixture materials flow A (12) and generation reaction gas mixtures input materials flow A (4).

All loads of propane on the amount catalyzer on all column plates (do not have inert material and calculate) are always 350 l (STP)/lh.

The inlet pressure of reaction gas mixtures input materials flow A is 2.3 crust.Its temperature is 500 ℃.Pressure drop through dehydrogenation reactor is about 200 millibars.Air (500 ℃, reaction pressure) is injected reaction gas mixtures in (under every kind of situation before the hybrid element) second catalyst bed upstream and the 3rd catalyst bed upstream (on the flow direction).Amount makes that the top temperature in catalyst bed downstream is 575-580 ℃ under every kind of situation.

II. propylene heterogeneous catalysis two-stage partial oxygen changes into acrylic acid universal test device and its operator scheme

Test is arranged

First step of reaction:

With reaction tubes (V2A steel; External diameter 30mm, wall thickness 2mm, internal diameter 28mm, length: 350cm, and heat pipe (external diameter 10mm), being the center configuration thermoelectric converter in the middle of the reaction tubes, the temperature in the reaction tubes on its total all length can be with this thermoelectric converter mensuration) followingly feed by top to bottom: part 1: long 50cm

Geometrical dimension is that the talcum ring of 7mm * 7mm * 4mm (external diameter * length * internal diameter) is as elementary bed.

Part 2: long 140cm

20 weight % (as selecting 30 weight %) geometrical dimension is the talcum ring of 5mm * 3mm * 2mm (external diameter * length * internal diameter) and 80 weight % (as the selection 70 weight %) catalyst charge from the uniform mixture of the not supported catalyst of part 3.

Part 3: long 160cm

The annular of DE-A 10046957 embodiment 1 (5mm * 3mm * 2mm=external diameter * length * internal diameter) is supported catalyst (stoichiometry: [Bi not ₂W ₂O ₉2WO ₃] _0.5[Mo ₁₂Co _5.5Fe _2.94Si _1.59K _0.08O _x] ₁)) catalyst charge.As selection, also can use the catalyzer EUC1-EUC11 of Research Disclosure on the 29th No.497012 August in 2005 here.

To the bottom, the salt bath A that pumps into by adverse current makes first 175cm constant temperature from the top.The salt bath B that pumps into by adverse current makes first 175cm constant temperature.

Second step of reaction:

With reaction tubes (V2A steel; External diameter 30mm, wall thickness 2mm, internal diameter 28mm, length: 350cm, and heat pipe (external diameter 10mm), being the center configuration thermoelectric converter in the middle of the reaction tubes, the temperature in the reaction tubes on its total all length can be with this thermoelectric converter mensuration) followingly feed by top to bottom: part 1: long 20cm

Part 2: long 90cm

25 weight % (as selecting 30 weight %) geometrical dimension is the talcum ring of 7mm * 3mm * 4mm (external diameter * length * internal diameter) and 75 weight % (as the selection 70 weight %) catalyst charge from the uniform mixture of the coated catalysts of part 4.

Part 3: long 50cm

15 weight % (as selecting 20 weight %) geometrical dimension is the talcum ring of 7mm * 3mm * 4mm (external diameter * length * internal diameter) and 85 weight % (as the selection 80 weight %) catalyst charge from the uniform mixture of the coated catalysts of part 4

Part 4: long 190cm

Annular (5mm * 3mm * 24mm=external diameter * length * internal diameter) coated catalysts (stoichiometry: Mo of DE-A 10046928 preparation embodiment 5 ₁₂V ₃W _1.2Cu _2.4O _x)) catalyst charge.

To the bottom, the salt bath C that pumps into by adverse current makes first 175cm constant temperature from the top.The salt bath D that pumps into by adverse current makes second 175cm constant temperature.

III. in new pilot plant, prepare acrylic acid (description steady state operation) by propane

The reaction gas mixtures input materials flow A that will have following content (based on total gas volume %) infeeds first catalyst bed of the reactor of column plate described in the I:

Volume %

Vinylformic acid 0.01

Acetate 0.015

Water 9.23

1-butylene 0.01

Iso-butylene 0.02

Propane 18.46

Propylene 3.98

Ethane 1.16

Ethene 0.22

CO ₂ 2.34

CO 0.26

N ₂ 59.7

O ₂ 1.62

CH ₄ 0.12

H ₂ 2.83

It is by following the obtaining of (it comprises) (with order of entrap bubble (23 ℃, 3.1 crust), fresh propane (25 ℃, 4 crust), hydrogen (25 ℃, 8 crust), steam (200 ℃, 2.5 crust), dehydrogenation cycle gas (600 ℃, 1.9 crust)):

-41.9 volume % are from the entrap bubble (the initial materials flow 2 of gaseous state) of partial oxidation, and it has following content:

Volume %

Vinylformic acid 0.02

Acetate 0.04

H ₂O 2.73

Iso-butylene 0.01

Propenal 0.05

Propane 17.30

Propylene 0.32

Ethane 1.20

Ethene 0.22

CO ₂ 2.41

CO 0.61

N ₂ 71.21

O ₂ 3.87

The fresh propane of-3.9 volume % (the initial materials flow 3 of gaseous state), it has following content:

Volume %

Propane 98.91

Trimethylmethane 0.05

Propylene 0.1

Ethane 0.92

Ethene 0.01

-1.02 volume % molecular hydrogens (the initial materials flow 4 of gaseous state)

-2.03 volume % steam (the initial materials flow 5 of gaseous state)

-51.15 volume % dehydrogenation cycle gases (product gas mixture A stream 1 or the initial materials flow 1 of gaseous state)

Entrap bubble, fresh propane, hydrogen and steam with specified order in conjunction with to obtain starting the jet mixture stream and by producing 500 ℃, 2.3 crust with product gas mixture A stream 2 indirect heat exchange.

The product gas mixture A stream 2 that produces has following content:

Volume %

H ₂O 11.84

Iso-butylene 0.01

Propane 14.32

Propylene 7.52

Ethane 1.21

Ethene 0.26

CO ₂ 2.61

N ₂ 58.41

O ₂ 0.23

H ₂ 3.55

Be present in propane in the product gas mixture A stream 2 and propylene by from Haltermann, the PKWF 4/7af technical grade tetradecane of Germany absorbs as absorbing in the absorption agent to be removed, and by the air stripping to obtain the following charging gas that is used for partial oxidation, it does not have following content so that wherein do not contain its (program as DE-A 10 2,004 032 129 as described in):

Volume %

H ₂O 2.39

The tetradecane 0.01

Iso-butylene 0.01

Propane 15.15

Propylene 7.95

Ethane 1.10

Ethene 0.20

CO ₂ 1.05

N ₂ 56.99

O ₂ 15.16

This charging gaseous mixture (it is positioned at beyond the explosive range) is used to load described first partial oxidation reaction stage.Propylene load in the fixed bed catalyst charging is chosen as 185 l (STP)/lh.The pressure of first step of reaction inlet is 3.1 crust.T _A＝322℃；T _B＝328℃。

The product gas mixture that leaves first step of reaction has following content:

Volume %

Vinylformic acid 0.46

Acetate 0.14

H ₂O 10.65

1-butylene 0.01

Propenal 6.99

Propane 15.16

Propylene 0.17

Ethane 1.10

Ethene 0.20

CO ₂ 1.62

CO 0.23

N ₂ 57.02

O ₂ 6.25

C ^P _A,, be 64.5 moles of % at the propylene conversion of reactor A end.

C ^P _B,, be 94.9 moles of % at the propylene conversion of reactor B end.

Competent air (25 ℃) is metered in the product gas mixture in first stage O in the mixture of generation ₂: the propenal mol ratio is 1.25.

This mixture is directly used in filling second step of reaction (T=231.7 ℃) then.

The propenal load is 152 l (STP)/lh on the stationary catalyst bed.

T _C＝263℃；T _D＝269℃。Second step of reaction ingress pressure is 2.1 crust.

The product gas mixture that leaves second step of reaction has following content:

Volume %

Vinylformic acid 6.72

Acetate 0.22

H ₂O 11.06

Formaldehyde 0.14

Propenal 0.05

Formic acid 0.03

Maleic anhydride 0.06

Phenylformic acid 0.01

Propane 14.62

Propylene 0.28

Ethane 1.02

Ethene 0.18

CO ₂ 2.03

CO 0.52

N ₂ 59.86

O ₂ 3.20

Propionic acid 0.0032

C ^A _C,, be 68.1 moles of % in the acrolein conversion rate of reactor C-terminal.

C ^A _D,, be 99.3 moles of % in the acrolein conversion rate of reactor D end.

In two step of reaction, reaction gas mixtures is downward through two catalyst tubes from the top.

Content is analyzed by gc analysis.

Take out from product gas mixture in the exemplary of vinylformic acid such as DE-A 10 2,004 032 129, initial materials flow 2 is recycled to the heterogeneous catalysis dehydrogenation to entrap bubble as gaseous state.

Method also can be carried out as described, but difference is each catalyzer column plate among the reaction zone A dehydrogenation catalyst of same amount only is housed, and does not promptly additionally use inert material with dilution.

IV.III. the change that increases with the operating time in the method

Along with operating time of pilot plant increases, even when replacing when dehydrogenation catalyst regeneration or by the charging of new generation, propylene content decline among the product gas mixture materials flow A.

Simultaneously, can detect maximum temperature reduction in first stationary catalyst bed (on the flow direction) in the column plate reactor.

Along with entrap bubble, fresh propane, steam (indirect heat exchange then) and then only the order of molecular hydrogen produce and start the jet mixture stream, can in new operation, recover baseline results.

Claims

1. method by propane to prepare acryl aldehyde or vinylformic acid or its mixture, wherein:

Product gas mixture materials flow A is by leaving first reaction zone A and be divided into two kinds of product gas mixture A streams 1 and 2 with same composition by wherein discharging, initial materials flow 1 is recycled to first reaction zone A to product gas mixture A stream 1 as gaseous state in first kind of gas circulation method

Product gas mixture materials flow B leaves reaction zone B, in second disengaging zone B, taking-up is present in the target product among the product gas mixture materials flow B, and from comprising unconverted propane, in the remaining residue gas of molecular oxygen and any unconverted propylene, to comprise unconverted propane, initial materials flow 2 is recycled to reaction zone A at least a portion of molecular oxygen and any unconverted propylene as gaseous state in second kind of gas circulation method, condition is the initial materials flow 2 of gaseous state, 3 and 4 combine to obtain gaseous state with the initial materials flow of any additional gaseous that is different from the initial materials flow 1 of gaseous state and to start the spray mixture materials flow, comprise and start nozzle, the mixing zone, the squirt pump of scatterer and suction nozzle starts the spray mixture materials flow to operate as starting jet with gaseous state subsequently, point to the inlet of first reaction zone A via mixing zone and scatterer by the jet transfer direction of starting of starting the nozzle decompression, the suction direction of suction nozzle is on the Way out of the product gas mixture materials flow A of first reaction zone of guiding A, and along with product gas mixture materials flow A is divided into two seed flows 1 and 2, the pressure of the reduction that produces in suction nozzle is with 1 suction of product gas mixture A stream and along with simultaneously it being passed through mixing zone via scatterer with its conveying with starting jet to mix, the reaction gas mixtures input materials flow A that forms like this is released into the inlet of first reaction zone A

Wherein:

The initial materials flow 2 of gaseous state and 3 and the initial materials flow of any additional gaseous that is different from gaseous stream 1 and 4 at first with any order in conjunction with only adding then in the materials flow of gaseous state starting mixt and start the spray mixture materials flow to form gaseous state to obtain the initial materials flow 4 of materials flow of gaseous state starting mixt and gaseous state.

2. according to the process of claim 1 wherein that reaction gas mixtures input materials flow A obtains by five kinds of initial materials flows 1,2,3,4 of different gaseous states and 5 combinations and the initial materials flow 5 of gaseous state is steam.

3. according to the method for claim 2, the wherein said initial materials flow of gaseous state that is different from the initial materials flow 1 of gaseous state and 4 with the order of the initial materials flow 2 of gaseous state, the initial materials flow 5 of gaseous state and the initial materials flow 3 of gaseous state then in conjunction with to obtain the materials flow of described gaseous state starting mixt.

4. according to each method among the claim 1-3, wherein arrive no more than 30 seconds of the effluxion of first catalyst bed of reaction zone A at flow direction to reaction gas mixtures input materials flow A from the formation time of starting the spray mixture materials flow.

5. according to each method among the claim 1-3, wherein arrive no more than 10 seconds of the effluxion of first catalyst bed of reaction zone A at flow direction to reaction gas mixtures input materials flow A from the formation time of starting the spray mixture materials flow.

6. according to each method among the claim 1-3, wherein reaction zone A is the column plate reactor.

7. according to the method for claim 4, wherein reaction zone A is the column plate reactor.

8. according to the method for claim 5, wherein reaction zone A is the column plate reactor.

9. according to each method among the claim 1-3, part heterogeneous catalysis dehydrogenation self-heating in reaction zone A of wherein said propane is carried out.

10. according to the method for claim 7 or 8, part heterogeneous catalysis dehydrogenation self-heating in reaction zone A of wherein said propane is carried out.