CN104955569A - Method for the oxidative dehydrogenation of n-butenes to butadiene - Google Patents

Abstract

The invention relates to a catalyst which is obtainable from a catalyst precursor comprising a catalytically active multimetal oxide which contains molybdenum and at least one further metal and is of the general formula (I) Mo12BiaFebCocNidCreX1 fX2 gOx,in which the variables have the following meaning: X1=W, Sn, Mn, La, Ce, Ge, Ti, Zr, Hf, Nb, P, Si, Sb, Al, Cd and/or Mg; X2=Li, Na, K, Cs and/or Rb, a=0.1 to 7, preferably 0.3 to 1.5; b=0 to 5, preferably 2 to 4; c=0 to 10, preferably 3 to 10; d=0 to 10; e=0 to 5, preferably 0.1 to 2; f=0 to 24, preferably 0.1 to 2; g=0 to 2, preferably 0.01 to 1; and x = a number which is determined by the valency and frequency of the elements in (I) that are different from oxygen, characterized in that the catalyst has the shape of a hollow cylinder, wherein the inner diameter is 0.2 to 0.8-times the outer diameter and the length is 0.5 to 2.5-times the outer diameter, and in that the catalyst precursor does not contain pore formers.

Description

N-butene oxidative dehydrogenation is become the method for butadiene

The present invention relates to the catalyst, particularly coated catalysts for n-butene oxidative dehydrogenation being become butadiene, its purposes and n-butene oxidative dehydrogenation is become the method for butadiene.

Butadiene is a kind of important basic chemicals and for such as preparing synthetic rubber (dienite, SBR styrene butadiene rubbers or acrylonitrile-butadiene rubber) or for the preparation of thermoplasticity terpolymer (acrylonitrile-butadiene-styrene copolymer).Butadiene also changes into sulfolane, chlorobutadiene and Isosorbide-5-Nitrae-hexamethylene diamine (by Isosorbide-5-Nitrae-dichloro-butenes and adiponitrile).In addition, butadiene can dimerization with produce can dehydrogenation to form cinnamic VCH.

Butadiene is prepared by the thermal cracking (steam cracking) of saturated hydrocarbons, and wherein naphtha is typically used as raw material.The steam cracking of naphtha obtains methane, ethane, ethene, acetylene, propane, propylene, propine, allene, butane, butylene, butadiene, butine, methyl-prop diene, C ₅the hydrocarbon mixture of hydrocarbon and higher hydrocarbon.

Butadiene also obtains by the oxidative dehydrogenation of n-butene (1-butylene and/or 2-butylene).Any mixture comprising n-butene can be used as starting gas mixture n-butene oxidative dehydrogenation being become butadiene.Such as, can use and comprise n-butene (1-butylene and/or 2-butylene) as key component and can by the C from naphtha cracker by butadiene and removing of isobutene ₄the cut that cut obtains.In addition, comprise 1-butylene, cis-2-butene, Trans-2-butene or its mixture and also can be used as starting gas by the admixture of gas that the dimerization of ethene obtains.In addition, comprise n-butene and can be used as starting gas by the admixture of gas that fluid catalytic cracking (FCC) obtains.

Comprise n-butene and be used as n-butene oxidative dehydrogenation to become the admixture of gas of the starting gas in butadiene also to prepare by comprising the admixture of gas Non-oxidative dehydrogenation of normal butane.WO2005/063658 discloses the method being prepared butadiene by normal butane, and it comprises step:

A) provide containing n-butane feed air-flow a;

B) will to feed at least one first dehydrogenation zone containing n-butane feed air-flow a and by normal butane nonoxidation catalytic dehydrogenation to obtain comprising normal butane, 1-butylene, 2-butylene, butadiene, hydrogen, low boiling secondary component and may the product gas flow b of steam;

C) will to feed from the product gas flow b of nonoxidation catalytic dehydrogenation and oxygen-containing gas at least one second dehydrogenation zone and by 1-butylene and 2-butylene oxidation-dehydrogenation to obtain comprising normal butane, 2-butylene, butadiene, hydrogen, low boiling secondary component and steam and the product gas flow c with the butadiene content higher than product gas flow b;

D) hydrogen, low boiling secondary component and steam is removed to obtain the C be substantially made up of normal butane, 2-butylene and butadiene ₄product gas flow d;

E) by extractive distillation by C ₄product gas flow d is separated into the recycle stream e1 be substantially made up of normal butane and 2-butylene and the stream e2 be substantially made up of butadiene, and stream e1 is recycled in the first dehydrogenation zone.

The method uses raw material especially effectively.Therefore, the loss of raw material normal butane minimizes by making unreacted normal butane be recycled in dehydrogenation.High butadiene yield is realized by the combination of nonoxidation catalytic dehydrogenation and oxidative dehydrogenation.With to prepare butadiene by cracking relative, the method demonstrates high selectivity.Do not obtain accessory substance.Eliminate butadiene and the complex separations from the product gas mixture of cracking method.

WO2009/124945 discloses the coated catalysts for 1-butylene and/or 2-butylene oxidation-dehydrogenation being become butadiene, and it can be obtained by the catalyst precarsor comprising following component:

(a) carrier,

(b) shell, described shell comprises: (i) comprises molybdenum and other metal of at least one and have the catalytic activity poly-metal deoxide of following general formula:

Mo ₁₂Bi _aCr _bX ¹ _cFe _dX ² _eX ³ _fO _y

Wherein:

X ¹=Co and/or Ni,

X ²=Si and/or Al,

X ³=Li, Na, K, Cs and/or Rb,

0.2≤a≤1，

0≤b≤2，

2≤c≤10，

0.5≤d≤10，

0≤e≤10，

0≤f≤0.5, and

The number that y=is determined by the chemical valence of element and abundance that are different from oxygen to realize neutral charge,

(ii) at least one pore-forming agent.

As the carrier of coated catalysts, use the talcum ball with the diameter of 2-3mm.

WO 2010/137595 discloses the multi-metal-oxide catalyst for olefin oxidation being dehydrogenated to diene, and it comprises at least molybdenum, bismuth and cobalt and have general formula:

Mo _aBi _bCo _cNi _dFe _eX _fY _gZ _hSi _iO _j。

In the formula, X is the element that at least one is selected from magnesium (Mg), calcium (Ca), zinc (Zn), cerium (Ce) and samarium (Sm).Y is the element that at least one is selected from sodium (Na), potassium (K), rubidium (Rb), caesium (Cs) and thallium (Tl).Z is the element that at least one is selected from boron (B), phosphorus (P), arsenic (As) and tungsten (W).A-j is the atomic fraction of each element, wherein a=12, b=0.5-7, c=0-10, d=0-10, (wherein c+d=1-10), e=0.05-3, f=0-2, g=0.04-2, h=0-3 and I=5-48.Do not provide the details of the geometry about method for producing propylene oxide.In an embodiment, there is composition Mo ₁₂bi ₅co _2.5ni _2.5fe _0.4na _0.35b _0.2k _0.08si ₂₄and the catalyst with the crumb form of 5mm diameter and 4mm height is for becoming butadiene by n-butene oxidative dehydrogenation.

N-butene oxidative dehydrogenation is being become in butadiene, carbonaceous material precursor can be formed, and these finally can cause the charing of catalyst and deactivation also to deposit and block pipeline and the assembly in oxidative dehydrogenation reactor (ODH reactor) downstream.This kind of carbonaceous material precursor is such as styrene, anthraquinone and Fluorenone.

The object of this invention is to provide method n-butene oxidative dehydrogenation being become butadiene, wherein form the carbonaceous material precursor of small amount.

This object is realized by the catalyst that can be obtained by the catalyst precarsor comprising following component:

Comprise molybdenum and other metal of at least one and there is the catalytic activity poly-metal deoxide of general formula (I):

Mo ₁₂Bi _aFe _bCo _cNi _dCr _eX ¹ _fX ² _gO _x(I)，

Wherein variable has following implication:

X ¹=W, Sn, Mn, La, Ce, Ge, Ti, Zr, Hf, Nb, P, Si, Sb, Al, Cd and/or Mg;

X ²=Li, Na, K, Cs and/or Rb,

A=0.1-7, preferred 0.3-1.5;

B=0-5, preferred 2-4;

C=0-10, preferred 3-10;

d＝0-10；

E=0-5, preferred 0.1-2;

F=0-24, preferred 0.1-2;

G=0-2, preferred 0.01-1; And

The chemical valence of the element of oxygen and the number of abundance decision is different from during x=serves as reasons (I);

Wherein catalyst has hollow cylinder shape, wherein internal diameter be external diameter 0.2-0.8 doubly and length be the 0.5-2.5 of external diameter doubly, and catalyst precarsor does not comprise any pore-forming agent.

Surprisingly the formation of discovery carbonaceous material precursor is pressure correlation.Therefore, specific carbonaceous material precursor, such as styrene, anthraquinone and Fluorenone be formed in the pressure of more than reactor inlet place 1.3 bar absolute pressure under disproportionately improve.Catalyst used according to the invention demonstrates pressure drop low especially, and oxidative dehydrogenation can under low pressure be carried out.

The use of pore-forming agent can improve the transportation performance in catalyst granules.But it causes expense high in catalyst preparing, because other processing step may must be introduced.In addition, the condition of heat treatment must accurately be monitored with the decomposition preventing pore-forming agent too fast.In addition, the wear resistence of catalyst greatly can reduce owing to using pore-forming agent.May to be accumulated in reactor beds by the material of attrition of catalyst and to cause pressure drop greatly to improve.

Catalyst of the present invention can be full active catalyst or coated catalysts.If it is coated catalysts, then it has carrier (a) and shell (b), and described shell (b) comprises containing molybdenum and other metal of at least one and has the catalytic activity poly-metal deoxide of general formula (I).The shell (b) of catalyst precarsor does not comprise any pore-forming agent.

Preferred catalyst has the size that external diameter × internal diameter × length is (4-10mm) × (2-8mm) × (2-10mm).Particularly preferred catalyst has the size that external diameter × internal diameter × length is (5-8mm) × (3-5mm) × (2-6mm).

If catalyst is coated catalysts, then carrier (a) preferably has the size that external diameter × internal diameter × length is (4-10mm) × (2-8mm) × (2-10mm).Carrier particularly preferably has the size that external diameter × internal diameter × length is (5-8mm) × (3-5mm) × (2-6mm).The layer thickness D comprising the shell (b) of the multimetal oxide compositions containing molybdenum and other metal of at least one is generally 5-1000 μm.Preferred 10-800 μm, particularly preferably 50-600 μm, very particularly preferably 80-500 μm.

Pressure drop in catalyst bed can be characterized by following relation:

$\frac{f}{dp}=\frac{\mathrm{\Δ}p/l}{Gv}$

Wherein f is pressure-drop coefficient, and dp is the characteristic length of a particle, and Δ p is the pressure drop on bed, and l is the length of bed, and v is gas velocity, and G is cross section load.Cross section load means the cross-sectional area of mass flow divided by reactor tube of feed gas.Cross section load is generally 1-5kg/ (m ²and pressure drop is 20-400 millibar/rice bed length s).At 3kg/ (m ²under the gas velocity of cross section load s), the bed length of 5 meters and 2m/s, catalyst bed demonstrates 100-2000 millibar usually, preferred 250-1500 millibar, the particularly preferably pressure drop of 350-1000 millibar.333-6667m is generally than f/dp ^-1, preferred 833-5000m ^-1, even more preferably 1167-3333m ^-1.

Be suitable for the catalyst of oxidative dehydrogenation usually based on containing Mo-Bi-O poly-metal deoxide system, it also comprises iron usually.Generally speaking, catalyst system comprises other catalyst component from periodic table 1-15 race, such as potassium, caesium, magnesium, zirconium, chromium, nickel, cobalt, cadmium, tin, lead, germanium, lanthanum, manganese, tungsten, phosphorus, cerium, aluminium or silicon.Iron content ferrite is also proposed as catalyst.

In a preferred embodiment, poly-metal deoxide comprises cobalt and/or nickel.In another preferred embodiment of the present, poly-metal deoxide comprises chromium.In another preferred embodiment of the present, poly-metal deoxide comprises manganese.

Example containing Mo-Bi-Fe-O poly-metal deoxide is the poly-metal deoxide comprising Mo-Bi-Fe-Cr-O or Mo-Bi-Fe-Zr-O.Preferred system is such as described in US 4,547,615 (Mo ₁₂biFe _0.1ni ₈zrCr ₃k _0.2o _xand Mo ₁₂biFe _0.1ni ₈alCr ₃k _0.2o _x), US 4,424,141 (Mo ₁₂biFe ₃co _4.5ni _2.5p _0.5k _0.1o _x+ SiO ₂), DE-A 25 30 959 (Mo ₁₂biFe ₃co _4.5ni _2.5cr _0.5k _0.1o _x, Mo _13.75biFe ₃co _4.5ni _2.5ge _0.5k _0.8o _x, Mo ₁₂biFe ₃co _4.5ni _2.5mn _0.5k _0.1o _xand Mo ₁₂biFe ₃co _4.5ni _2.5la _0.5k _0.1o _x), US 3,911,039 (Mo ₁₂biFe ₃co _4.5ni _2.5sn _0.5k _0.1o _x), DE-A 25 30 959 and DE-A 24 47 825 (Mo ₁₂biFe ₃co _4.5ni _2.5w _0.5k _0.1o _x) in.

Suitable poly-metal deoxide and preparation thereof are also described in US 4,423,281 (Mo ₁₂biNi ₈pb _0.5cr ₃k _0.2o _xand Mo ₁₂bi _bni ₇al ₃cr _0.5k _0.5o _x), US 4,336,409 (Mo ₁₂biNi ₆cd ₂cr ₃p _0.5o _x), DE-A 26 00 128 (Mo ₁₂biNi _0.5cr ₃p _0.5mg _7.5k _0.1o _x+ SiO ₂) and DE-A 24 40 329 (Mo ₁₂biCo _4.5ni _2.5cr ₃p _0.5k _0.1o _x) in.

The particularly preferred catalytic activity poly-metal deoxide comprising molybdenum and other metal of at least one has general formula (Ia):

Mo ₁₂Bi _aFe _bCo _cNi _dCr _eX ¹ _fX ² _gO _y(Ia)，

Wherein:

X ¹⁼si, Mn and/or Al,

X ²⁼li, Na, K, Cs and/or Rb,

0.2≤a≤1，

0.5≤b≤10，

0≤c≤10，

0≤d≤10，

2≤c+d≤10

0≤e≤2，

0≤f≤10，

0≤g≤0.5，

The number that y=is determined by the chemical valence of element and abundance that are different from oxygen in (1a) is to realize neutral charge.

Preferably in two kinds of metal Co and Ni, its catalytic activity oxide composition only comprises the catalyst (d=0) of Co.X ¹be preferably Si and/or Mn, and X ²be preferably K, Na and/or Cs, wherein X ²be particularly preferably K.

Stoichiometric coefficient a in formula (Ia) preferably makes 0.4≤a≤1, particularly preferably 0.4≤a≤0.95.The value of variable b is preferably 1≤b≤5, particularly preferably 2≤b≤4.Stoichiometric coefficient c+d and be preferably 4≤c+d≤8, particularly preferably 6≤c+d≤8.Stoichiometric coefficient e is preferably 0.1≤e≤2, particularly preferably 0.2≤e≤1.Stoichiometric coefficient g is advantageously >=0.Preferably 0.01≤g≤0.5, particularly preferably 0.05≤g≤0.2.

The stoichiometric coefficient y of oxygen is worth from cationic chemical valence and abundance to keep neutral charge.Have mol ratio Co/Ni at least 2:1, preferably at least 3:1, particularly preferably at least the coated catalysts of the present invention of the catalytic activity oxide composition of 4:1 is favourable.It is preferred that only there is Co.

Coated catalysts is by being applied to the layer of the poly-metal deoxide comprised containing molybdenum and other metal of at least one by adhesive on carrier and the dry and heat treatment and preparing by coated carrier (coated catalysts precursor).

Before finished heat treatment, the layer comprising the poly-metal deoxide of coated catalysts precursor does not comprise any pore-forming agent as malonic acid, melamine, nonyl phenol ethoxylate, stearic acid, glucose, starch, fumaric acid and butanedioic acid.

Treat the used according to the invention poly-metal deoxide in small, broken bits comprising molybdenum and other metal of at least one in principle by the close dry mixture of the initial compounds of the element composition of preparation catalytic activity oxide composition, and by close dry mixture 150-650 DEG C temperature lower calcination and obtain.

the preparation of catalyst

The preparation of multimetal oxide compositions

For preparing suitable multimetal oxide compositions in small, broken bits, the known initial compounds being different from the elemental constituent of oxygen with required multimetal oxide compositions is used as raw material with respective stoichiometric proportion, very close by these generations, dry mixture preferably in small, broken bits, then makes this dry mixture through heat-treated (calcining).Source can be oxide or the compound changing into oxide by heating at least in the presence of oxygen.Therefore, except oxide, halide, nitrate, formates, oxalates, acetate, carbonate or hydroxide can be used especially as initial compounds.

Other suitable initial compounds of molybdenum is its oxo-compound (molybdate) or the acid derived from these.

Suitable initial compounds particularly its nitrate of Bi, Cr, Fe and Co.

The close mixed principle of initial compounds can be carried out with dry form or with the form of the aqueous solution or suspension.

Aqueous suspension can such as by comprising the solution of at least molybdenum and comprise the aqueous solution combination of all the other metals and prepare.Alkali metal or alkaline-earth metal can be present in two kinds of solution.Precipitate by solution is combined and carry out, and this causes the formation of suspension.Temperature in precipitation can be greater than room temperature, preferably 30 DEG C to 95 DEG C, particularly preferably 35 DEG C to 80 DEG C.Then can by the suspension aging specific time at elevated temperatures.The aging time is generally 0-24 hour, preferred 0-12 hour, particularly preferably 0-8 hour.

Temperature between aging period is generally 20 DEG C to 99 DEG C, preferably 30 DEG C to 90 DEG C, particularly preferably 35 DEG C to 80 DEG C.Usually by stirring, suspension is mixed between precipitation and aging period.The pH of mixed solution or suspension is generally pH1 to pH12, preferred pH2 to pH11, particularly preferably pH3 to pH10.

Water remove generation solid, it represents the intimate mixture of metal component added.Drying steps is undertaken by evaporation, spraying dry or freeze-drying etc. usually.Drying is carried out preferably by spraying dry.For this reason, by suspension at elevated temperatures by the fog-spray nozzle atomization usually at the temperature of 120 DEG C to 300 DEG C, and desciccate is collected at the temperature of >60 DEG C.Be generally by the residual humidity content at 120 DEG C, spray-dried powders drying measured and be less than 20 % by weight, be preferably less than 15 % by weight, be particularly preferably less than 12 % by weight.

The preparation of full active catalyst

In a further step, spray-dried powders is changed into formed body.Possible shaping assistant (lubricant) is such as water, boron trifluoride or graphite.Based on to be formed with the composition obtaining catalyst precarsor formed body, add general≤10 % by weight, usually≤6 % by weight, usually≤4 % by weight shaping assistants.Above-mentioned addition is generally >0.5 % by weight.Be graphite according to the preferred lubricant of the present invention.

Carry out at the calcining of the catalyst precarsor formed body temperature usually more than 350 DEG C.But, during heat treatment process, be usually no more than the temperature of 650 DEG C.According to the present invention, the temperature in heat treatment, advantageously not more than 600 DEG C, preferably more than 550 DEG C, is particularly preferably no more than 500 DEG C.In addition, the temperature of the catalyst precarsor formed body Heat Treatment in the inventive method is preferably more than 380 DEG C, advantageously more than 400 DEG C, particularly advantageously more than 420 DEG C, very particularly preferably more than 440 DEG C.Heat treatment also can be divided into multiple stage in time.Such as, first at 150-350 DEG C, can heat-treat at the temperature of preferred 220-280 DEG C, subsequently at 400-600 DEG C, heat-treat at the temperature of preferred 430-550 DEG C.Multiple hours (being usually greater than 5 hours) is carried out in the heat treatment of catalyst precarsor formed body usually.Heat treated total duration usually extends to and is greater than 10 hours.Usually the processing time of 45 hours or 35 hours is no more than in the heat treatment of catalyst precarsor formed body.Be generally total processing time and be less than 30 hours.In the heat treatment of catalyst precarsor formed body preferably more than the temperature of 500 DEG C and the processing time in the temperature window of >=400 DEG C preferably extend to 5-30 hour.

The calcining of catalyst precarsor formed body can under an inert gas or under oxidizing atmosphere be as air (mixture of inert gas and oxygen) or at reducing atmosphere (such as inert gas, NH ₃, CO and/or H ₂or the mixture of methane) under carry out.Self-evident, heat treatment also can be carried out under a reduced pressure.The heat treatment of catalyst precarsor formed body in principle can in multiple stove type, such as can heated convection room, board-like stove, rotary tube furnace, carry out in belt calcinatory or shaft furnace.The heat treatment of catalyst precarsor formed body preferably as in DE-A 10046957 and WO 02/24620 carry out in the belt calciner recommended.The heat treatment of catalyst precarsor formed body below 350 DEG C usually be included in catalyst precarsor formed body needed for the elemental constituent of the catalyst thermal decomposition of originating relevant.This catabolic phase occurs usually in the methods of the invention during being heated to the temperature of <350 DEG C.

Catalytic activity multimetal oxide compositions can comprise chromium oxide.Except oxide, educt can be mainly halide, nitrate, formates, oxalates, acetate, carbonate and/or hydroxide.The thermal decomposition of chromium (III) compound becomes that chromium oxide (III) is main not to be relied on the presence or absence of oxygen containing chromium (VI) intermediate by several and carry out (see such as Therm.Anal.Cal. at 70 DEG C to 430 DEG C, 72,2003,135 and Env.Sci.Tech.47,2013,5858).The existence of chromium oxide (VI) is dehydrogenated to diene to olefin catalytic oxidation, and particularly butylene catalytic oxidative dehydrogenation becomes butadiene optional.Due to the toxicity of chromium oxide (VI) and the harmfulness to environment, active material must oxygen-freeization chromium (VI).Chromium oxide (VI) content greatly depends on calcination condition, the maximum temperature particularly during calcining step and the time of staying.Temperature is higher and the time of staying is longer, then chromium oxide (VI) content is lower.

The formed body comprising catalytic activity multimetal oxide compositions obtained after calcining can be used as full active catalyst.In addition, for preparing coated catalysts, by grinding, the formed body comprising multimetal oxide compositions being changed into fine powder, being then applied on the outer surface of carrier by liquid adhesive.Fineness to be applied to the catalytic activity oxide composition on carrier surface can be mated with required thickness of the shell naturally.

The preparation of coated catalysts

The carrier material being suitable for coated catalysts of the present invention is porous or preferred non-porous aluminas, silica, zirconium dioxide, carborundum, or silicate is as magnesium silicate or alumina silicate (such as from C 220 grades of steatites of CeramTec).Carrier material is chemically inert.

Carrier material can be porous or atresia.Carrier material is preferably (total pore volume is preferably≤1 volume % based on the volume of carrier) of atresia.

Preferred hollow circular cylinder as carrier has the length of 2-10mm and the external diameter of 4-10mm.In addition, wall thickness is preferably 1-4mm.Particularly preferably annular carrier has the wall thickness of the length of 2-6mm, the external diameter of 5-8mm and 1-2mm.An example is for having the ring of geometry 7mm × 4mm × 3mm (external diameter × internal diameter × length) as carrier.

The layer thickness D comprising the multimetal oxide compositions of molybdenum and other metal of at least one is generally 5-1000 μm.Preferred 10-800 μm, particularly preferably 50-600 μm, very particularly preferably 80-500 μm.

The poly-metal deoxide comprising molybdenum and other metal of at least one is applied on carrier surface and to correspond to the mode of method described in the prior art, such as, can carries out as described in US-A 2006/0205978 and EP-A 0 714 700.

Generally speaking, by liquid adhesive, composition in small, broken bits is applied on carrier surface.Possible liquid adhesive is such as water, organic solvent or organic substance (such as organic solvent) solution in water or in organic solvent.

The solution comprising 20-95 % by weight water and 5-80 % by weight organic compound is particularly advantageously used as liquid adhesive.The content of organics of aforesaid liquid adhesive is preferably 5-50 % by weight, particularly preferably 8-30 % by weight.

Usually preferred under atmospheric pressure (1atm) boiling point or sublimation temperature be >=100 DEG C, the preferably >=organic bond of 150 DEG C or adhesive component.This kind of organic bond or adhesive component boiling point at atmosheric pressure or sublimation point are very particularly preferably simultaneously lower than the maximum calcination temperature used during the preparation containing molybdenum poly-metal deoxide in small, broken bits.This maximum calcination temperature is generally≤and 600 DEG C, be usually≤500 DEG C.

Particularly preferred liquid adhesive is the solution comprising 20-95 % by weight water and 5-80 % by weight glycerine.Glycerol content in these aqueous solution is preferably 5-50 % by weight, particularly preferably 8-35 % by weight.

Containing the application of molybdenum poly-metal deoxide in small, broken bits by will to be dispersed in containing the composition in small, broken bits of molybdenum multi-metal oxide in liquid adhesive and gained suspension spray to stirring, optional heat carrier is carried out, as described in DE-A 1642921, DE-A 2106796 and DE-A 2626887.After spraying completes, the water capacity of gained coated catalysts can by making hot-air be reduced by catalyst as described in DE-A 2909670.

But, preferably first carrier liquid adhesive is soaked, by wetting carrier is rolled in composition in small, broken bits, the composition in small, broken bits of poly-metal deoxide is applied on the surface of the carrier soaked with adhesive subsequently.For realizing required layer thickness, preferably repeatedly, the carrier be about to the first coating soaks said method again, then applies by contacting with dry composition in small, broken bits.

In order to carry out the method with commercial scale, suggestion uses method disclosed in DE-A 2909671, but preferably uses the adhesive recommended in EP-A 714700.That is, carrier to be coated is introduced in preferred angled (inclination angle is generally 30-90 DEG C) rotary container (such as swivel plate or coating cylinder).Rotary container hollow cylindrical carrier is delivered to below two with distance specific range and in continuously arranged metering device each other.First in two metering devices is advantageously nozzle, the carrier rolled liquid adhesive to be used spraying is also soaked in a controlled manner by it in swivel plate.It is outside and for such as feeding composition in small, broken bits by vibration chute that second metering device is positioned at the atomizer (atomizing) cone of the liquid adhesive sprayed into.The active compound powder that carrier absorption wetting to controllably feeds, to obtain the shell that bonds on the outer surface then by rolling movement this powder being pressed in cylindrical vector.

If necessary, the carrier making to have like this first coating is wetting can absorb another layer of composition layer in small, broken bits during further motion process to controllably by nozzle again during the rotary course subsequently.Usually intermittent drying is not needed.The applying partially or completely removed by final heat of liquid adhesive, such as by with hot gas as N ₂or air contacts and carries out.In a particularly preferred embodiment of said method, the coated catalysts with the shell be made up of the layer of two or more different components can be prepared in one operation.Significantly, the method generation pantostrat is being gone up and the satisfied attachment of ground floor on carrier surface each other.This is also applicable to the situation of annular carrier.

What produce adhesion promoter removes required temperature below the maximum calcination temperature of catalyst, is generally 200 DEG C to 600 DEG C.Preferably catalyst is heated to 240 DEG C to 500 DEG C, particularly preferably the temperature of 260 DEG C to 400 DEG C.Until the time of removing adhesion promoter can be multiple hours.Usually catalyst is heated to said temperature 0.5-24 hour to remove adhesion promoter.Time is preferably 1.5-8 hour, particularly preferably 2-6 hour.Gas flowing around catalyst can promote removing of adhesion promoter.Gas is preferably air or nitrogen, particularly preferably air.Removing in the baking oven that can such as flow through at gas of adhesion promoter, or carry out in suitable drying equipment is as belt dryer.

oxidative dehydrogenation (oxidative dehydrogenation, ODH)

The present invention also provides the full active catalyst of the present invention 1-butylene and/or 2-butylene oxidation-dehydrogenation being become the purposes in the method for butadiene with coated catalysts.Catalyst of the present invention demonstrates high activity, particularly and formed the high selectivity of 1,3-butadiene by 1-butylene and 2-butylene.

The present invention also provides method n-butene oxidative dehydrogenation being become butadiene, wherein the starting gas mixture of n-butene and oxygen-containing gas and optionally other inert gas or steam will be comprised, and in fixed bed reactors at the temperature of 220-490 DEG C with the catalyst exposure to arrange with stationary catalyst bed, wherein catalyst can be obtained by the catalyst precarsor comprising catalytic activity poly-metal deoxide, and described catalytic activity poly-metal deoxide comprises molybdenum and other metal of at least one and has general formula (I):

Mo ₁₂Bi _aFe _bCo _cNi _dCr _eX ¹ _fX ² _gO _x(I)，

Wherein variable has following implication:

X ¹=W, Sn, Mn, La, Ce, Ge, Ti, Zr, Hf, Nb, P, Si, Sb, Al, Cd and/or Mg;

X ²=Li, Na, K, Cs and/or Rb,

A=0.4-5, preferred 0.5-2;

B=0-5, preferred 2-4;

C=0-10, preferred 3-10;

d＝0-10；

E=0-10, preferred 0.1-4;

F=0-24, preferred 0.1-2;

G=0-2, preferred 0.01-1; And

The chemical valence of the element of oxygen and the number of abundance decision is different from during x=serves as reasons (I);

Wherein catalyst has hollow cylinder shape, wherein internal diameter be external diameter 0.2-0.8 doubly and length be the 0.5-2.5 of external diameter doubly, and catalyst precarsor does not comprise any pore-forming agent.

Full active catalyst used according to the invention and coated catalysts demonstrate low pressure drop.Therefore, oxidative dehydrogenation can under low pressure be carried out, and it is to the formation of carbonaceous material precursor and carbon-containing sediment on anticatalyst and in post processing.Generally speaking, reactor inlet pressure is <3 bar (table), preferred <2 bar (table), particularly preferably <1.5 bar (table).Generally speaking, reactor outlet pressure is <2.8 bar (table), preferred <1.8 bar (table), particularly preferably <1.3 bar (table).This value is higher, and the space time yield of reaction is larger, because more substantial reacting gas can be introduced in reactor.Select to be enough to the reactor inlet pressure overcoming flow resistance, until be present in the possible compression stage in device and following post processing.Generally speaking, answer device inlet pressure at least 0.01 bar (table), preferably at least 0.1 bar (table), particularly preferably 0.5 bar (table).Generally speaking, reactor outlet pressure is at least 0.01 bar (table), preferably at least 0.1 bar (table), particularly preferably 0.2 bar (table).This value is lower, and the formation of carbonaceous material precursor and carbon-containing sediment is lower on catalyst and in post processing.

Pressure drop on total catalyst bed is generally 0.01-2 bar (table), preferred 0.1-1.5 bar, particularly preferably 0.4-1.0 bar.This value is lower, and the formation of carbonaceous material precursor and carbon-containing sediment is lower on catalyst and in post processing.

The reaction temperature of oxidative dehydrogenation is controlled by the heat transfer medium be positioned at around reaction tube usually.As this liquid heat-transfer medium, such as salt can be used as the melt of potassium nitrate, potassium nitrite, natrium nitrosum and/or sodium nitrate, and metal is as the melt of the alloy of sodium, mercury and various metal.But, also can use ionic liquid or heat-transfer oil.The temperature of heat transfer medium is 220-490 DEG C, preferred 300-450 DEG C, particularly preferably 350-420 DEG C.

Due to the exothermal nature of reaction occurred, temperature during reaction can form focus higher than the heat transfer medium in the specific part of inside reactor.Position and the magnitude of focus are determined by reaction condition, but also by the thinner ratio of catalyst layer or mist by adjustment.Difference between hot(test)-spot temperature and heat-transfer medium temperature is generally 1-150 DEG C, preferred 10-100 DEG C, particularly preferably 20-80 DEG C.The temperature of catalyst bed end usually than the temperature height 0-100 DEG C of heat transfer medium, preferred high 0.1-50 DEG C, particularly preferably high 1-25 DEG C.

Oxidative dehydrogenation in the known all fixed bed reactors of prior art, such as, in board-like stove, fixed-bed tube reactor or shell-tube type reactor, or can be carried out in plate type heat exchanger reactor.Preferred shell-tube type reactor.

Oxidative dehydrogenation preferably uses catalyst of the present invention to carry out in fixed-bed tube reactor or fixed bed shell-tube type reactor.As other element in shell-tube type reactor, reactor tube is made up of steel usually.The wall thickness of reaction tube is generally 1-3mm.Their internal diameter is generally 10-50mm or 15-40mm, usually 20-30mm.The number being contained in the reaction tube in shell-tube type reactor is generally at least 1000 or 3000 or 5000, and preferably at least 10 000.The number being contained in the reaction tube in shell-tube type reactor is generally 15 000-30 000 or at the most 40 000 or at the most 50 000.Tend to get rid of the shell-tube type reactor had more than 50 000 reaction tubes.

The length of reaction tube is generally several meters at the most, and wherein typical tube length of reaction tube is 1-8 rice, usually 2-7 rice, usual 2.5-6 rice.

In reaction tube, difference is between instrumentation tubes and heat pipe usually.Although instrumentation tubes is those reaction tubes wherein in fact carrying out pending partial oxidation, heat pipe is primarily for monitoring and controlling the reaction temperature along reaction tube, and described reaction tube is the representative of all working pipe.For this reason, except stationary catalyst bed, heat pipe comprises temperature sensor sheath usually, and it has temperature sensor and is vertically positioned at the center of heat pipe.In shell-tube type reactor, the number of heat pipe is usually than the number much less of instrumentation tubes.The number of heat pipe is generally≤and 20.

In addition, as mentioned above, the catalyst bed of installing in the reactor can be made up of single district or 2 or more district.These districts can be made up of pure catalyst or with not diluting with starting gas or by the material of the component reaction of reacting the product gas formed.In addition, catalyst zone can be made up of full active catalyst or support type coated catalysts.

As starting gas, pure butylene (1-butylene and/or cis-/Trans-2-butene) can be used, also can use the admixture of gas comprising butylene.This mixture can such as be obtained by the Non-oxidative dehydrogenation of normal butane.Also can use and comprise n-butene (1-butylene and/or 2-butylene) as key component and by butadiene and removing of isobutene by the C from cracking naphtha ₄the cut that cut obtains.In addition, also can use comprise pure 1-butylene, cis-2-butene, Trans-2-butene or its mixture and the admixture of gas obtained by the dimerization of ethene as starting gas.Also can use comprise n-butene and the admixture of gas obtained by fluid catalytic cracking (FCC) as starting gas.In an embodiment of the inventive method, the starting gas mixture comprising n-butene is obtained by the Non-oxidative dehydrogenation of normal butane.Based on normal butane used, high butadiene yield obtains by being combined with the oxidative dehydrogenation of formed n-butene by nonoxidation catalytic dehydrogenation.

The nonoxidation catalytic dehydrogenation of normal butane obtains comprising the admixture of gas of butadiene, 1-butylene, 2-butylene and unreacted normal butane and secondary component.Common secondary component is hydrogen, steam, nitrogen, CO and CO ₂, methane, ethane, ethene, propane and propylene.The composition leaving the admixture of gas of the first dehydrogenation zone can be depending on the operator scheme of dehydrogenation and greatly changes.Therefore, when dehydrogenation is carried out along with introducing oxygen and other hydrogen, product gas mixture has quite high steam and oxycarbide content.Do not introducing in the operator scheme of oxygen, the product gas mixture from Non-oxidative dehydrogenation has quite high hydrogen content.

Product gas flow from the Non-oxidative dehydrogenation of normal butane comprises 0.1-15 volume % butadiene, 1-15 volume %1-butylene, 1-25 volume %2-butylene (cis/trans-2-butylene), 20-70 volume % normal butane, 1-70 volume % steam, 0-10 volume % low boiling hydrocarbon (methane, ethane, ethene, propane and propylene), 0.1-40 volume % hydrogen, 0-70 volume % nitrogen and 0-5 volume % oxycarbide usually.

Not further for product gas flow from Non-oxidative dehydrogenation post processing can be fed in oxidative dehydrogenation.

In addition, any impurity can be present in the starting gas of oxidative dehydrogenation not suppress the amount of effect of the present invention.Preparing in butadiene by n-butene (1-butylene and cis-/Trans-2-butene), the impurity that can mention is saturated and unsaturated, branching and non-branching hydrocarbon, such as methane, ethane, ethene, acetylene, propane, propylene, propine, normal butane, iso-butane, isobutene, pentane and diene are as 1,2-butadiene.The amount of impurity is generally 70% or less, and preferably 30% or less, more preferably 10% or less, particularly preferably 1% or less.The concentration in starting gas with the linear single olefin (n-butene and comparatively higher homologue) of 4 or more carbon atoms is not limited with any ad hoc fashion; It is generally 35.00-99.99 volume %, preferred 71.00-99.0 volume %, even more preferably 75.00-95.0 volume %.

In order to oxidative dehydrogenation is carried out in the conversion completely with butylene, need the oxygen with at least 0.5: the admixture of gas of n-butene mol ratio.Preferably with the oxygen of 0.55-10: n-butene compares work.For arranging this value, can by starting gas and oxygen or oxygen-containing gas as air and optional inert gas or steam in addition.Then gained oxygen-containing gas mixture is fed in oxidative dehydrogenation.

The used according to the invention gas comprising molecular oxygen is greater than 10 volume % for usually comprising, and is preferably greater than 15 volume %, even more preferably greater than the gas of 20 volume % molecular oxygens, and especially preferably air.The upper limit of molecular oxygen content is generally 50 volume % or less, preferably 30 volume % or less, even more preferably 25 volume % or less.In addition, any inert gas can comprise in the gas of molecular oxygen not suppress the amount of effect of the present invention to be present in.As possible inert gas, nitrogen, argon gas, neon, helium, CO, CO can be mentioned ₂and water.When nitrogen, the amount of inert gas is generally 90 volume % or less, preferably 85 volume % or less, even more preferably 80 volume % or less.When being different from the component of nitrogen, they are usually with 10 volume % or less, and preferably 1 volume % or less amount exist.If this quantitative change obtains too large, then required oxygen is provided to become more and more difficult to reaction.

In addition, inert gas as nitrogen and water (as steam) can with by starting gas with comprise molecular oxygen gas composition mist together be included.There is nitrogen to arrange oxygen concentration and to prevent the formation of explosive gas mixture, be equally applicable to steam.Also there is steam to control the carbonization of catalyst and to remove reaction heat.Water (as steam) and nitrogen to be preferably mixed in mist and to introduce in reactor.When being introduced in reactor by steam, preferably the introduction volume introduced based on above-mentioned starting gas is 0.2-5.0 (parts by volume), preferred 0.5-4, the even more preferably ratio of 0.8-2.5.When being introduced in reactor by nitrogen, preferably the introduction volume introduced based on above-mentioned starting gas is 0.1-8.0 (parts by volume), preferred 0.5-5.0, the even more preferably ratio of 0.8-3.0.

The content comprising the starting gas of hydrocarbon in mist is generally 4.0 volume % or more, preferably 6.0 volume % or more, even more preferably 8.0 volume % or more.On the other hand, the upper limit is 20 volume % or less, preferably 16.0 volume % or less, even more preferably 13.0 volume % or less.In order to avoid the formation of explosive gas mixture safely, before obtaining mist, first being introduced by nitrogen in starting gas or introducing comprises in the gas of molecular oxygen, by starting gas with comprise the gas and vapor permeation of molecular oxygen to obtain mist, then preferably introduces this mist.

During stable operation, the time of staying is in the reactor not limited with any ad hoc fashion in the present invention, but lower limit is generally 0.3 second or more, preferably 0.7 second or more, even more preferably 1.0 seconds or more.The upper limit is 5.0 seconds or less, preferably 3.5 seconds or less, even more preferably 2.5 seconds or less.The handling capacity of mist is 500-8000h with the ratio of the amount of the catalyst of inside reactor ^-1, preferred 800-4000h ^-1, even more preferably 1200-3500h ^-1.In stable operation, butylene air speed is on a catalyst (with g _butylene/ (g _catalyst* hour expression) be generally 0.1-5.0h ^-1, preferred 0.2-3.0h ^-1, even more preferably 0.25-1.0h ^-1.The volume of catalyst and quality are based on the complete catalyst be made up of carrier and active compound.

The Volume Changes factor describes the difference in flow between reactor inlet and outlet, and depends on the flow of reactor inlet place starting gas and the flow of reactor exit product gas.It can advantageously by inert component in reactor inlet and reactor exit reacting gas, the component of namely not reacting in any form in the reactor (such as Ar or N ₂) volumetric concentration determine.The Volume Changes factor can be 1-1.15, preferred 1-1.1, particularly preferably 1.01-1.08.

the post processing of product gas flow

The product gas flow leaving oxidative dehydrogenation comprises butadiene, usually also comprises unreacted normal butane and iso-butane, 2-butylene and steam.As secondary component, it usually comprises carbon monoxide, carbon dioxide, oxygen, nitrogen, methane, ethane, ethene, propane and propylene, possibility steam and is called the oxygen-containing hydrocarbon of oxygenate.Generally speaking, it only comprises 1-butylene and the isobutene of small scale.

The product gas flow leaving oxidative dehydrogenation such as can comprise 1-40 volume % butadiene, 20-80 volume % normal butane, 0-5 volume % iso-butane, 0.5-40 volume %2-butylene, 0-5 volume %1-butylene, 0-70 volume % steam, 0-10 volume % low boiling hydrocarbon (methane, ethane, ethene, propane and propylene), 0-40 volume % hydrogen, 0-30 volume % oxygen, 0-70 volume % nitrogen, 0-10 volume % oxycarbide and 0-10 volume % oxygenate.Oxygenate can be such as formaldehyde, furans, acetic acid, maleic anhydride, formic acid, methacrolein, methacrylic acid, crotonaldehyde, crotonic acid, propionic acid, acrylic acid, methyl vinyl ketone, styrene, benzaldehyde, benzoic acid, phthalic anhydride, Fluorenone, anthraquinone and butyraldehyde.

Some oxygenate can oligomeric and dehydrogenation further on catalyst surface and in post processing, to form the deposit comprising carbon, hydrogen and oxygen, hereinafter referred to carbonaceous material.Interruption during these deposits can cause method to operate, with cleaning and regeneration, is therefore undesirable.Typical carbonaceous material precursor comprises styrene, Fluorenone and anthraquinone.

Product gas flow has close to the temperature in the temperature of catalyst bed end at reactor exit.Then product gas flow is made to reach 150-400 DEG C, preferred 160-300 DEG C, particularly preferably the temperature of 170-250 DEG C.Can the pipeline that flows through of isolating product air-flow to maintain the temperature in required scope, but preferably use heat exchanger.This heat exchanger system can be any type, and condition is that the temperature of product gas remains on desired level by this system.As the example of heat exchanger, spiral heat exchanger, plate type heat exchanger, Dual-tube heat exchanger, multi-pipe heat exchanger, boiler spiral heat exchanger, boiler jacket heat-exchanger, liquid/liquid contact heat exchanger, air heat exchanger, direct contact heat transfer device and finned tube exchanger can be mentioned.Owing to being included in, a part in product gas is high boiling point by-products produced may be precipitated to time temperature required the temperature of product gas being arranged, and heat exchanger system preferably should have 2 or more heat exchangers.When 2 that provide or more heat exchangers arranged in parallel and therefore can obtain product gas in heat exchanger separately cooling, the high boiling point by-products produced amount precipitated in heat exchanger reduces, and therefore can extend the operating time of heat exchanger.As the alternative scheme of said method, 2 that provide or more heat exchangers can be arranged in parallel.Product gas is fed one or more, instead of in all heat exchangers, and can by other heat exchanger rotation after the specific operation time.In the method, cooling can be continued, recyclable a part of reaction heat and therewith concurrently, can remove that to be deposited in a heat exchanger high boiling point by-products produced.As organic solvent as mentioned above, can use any non-limiting solvent, condition is that it can dissolve high boiling point by-products produced, such as aromatic hydrocarbon solvent, such as toluene, dimethylbenzene etc., or basic aqueous solvent, such as sodium hydrate aqueous solution.

If product gas flow comprises the oxygen more than only little trace, then can carry out the processing step removing residual oxygen from product gas flow.Residual oxygen can be disturbed to this degree: it can cause Butadiene Peroxide in processing step subsequently formed and can serve as the initator of polymerisation.Unstable 1,3-butadiene can form dangerous Butadiene Peroxide in the presence of oxygen.This peroxide is viscous liquid.Their density is higher than the density of butadiene.Because they are also only slightly soluble in liquid 1,3-butadiene, they settle in the bottom of reservoir vessel.Although the chemical reactivity that they are lower, this peroxide is very unstable compound, and it spontaneously can decompose at the temperature of 85-110 DEG C.Special danger is the HI high impact sensitiveness of peroxide, and it explodes with the brisance of explosive.Polymer formed risk especially by during separated butadiene exist and the polymer deposits (formation of " puffed rice ") in tower can be caused there.Removing of oxygen is preferably carried out immediately after oxidative dehydrogenation.Generally speaking, carry out for this reason oxygen in the presence of a catalyst with catalytic combustion stage of the hydrogen reaction added in this stage.This makes oxygen content be down to little trace.

Then make from O ₂the product gas removing the stage reach with about temperature levels identical described in ODH reactor downstream region.The heat exchanger that is cooled through of Compressed Gas carries out, and described heat exchanger can be mixed with such as shell and tube exchanger, spiral heat exchanger or plate type heat exchanger.The heat herein removed is preferred for the heat integration in method.

By cooling, most of higher boiling secondary component is separated with product gas flow with water subsequently.This separation is preferably carried out in quenching.This quenching can comprise one or more stage.Preferred use wherein makes product gas directly contact with cooling medium, the method cooled thus.Cooling medium not by any special restriction, but preferably uses water or alkaline aqueous solution.

Preferred two benches quenching.The chilling temperature of product gas is along with different by the product gas obtained of reactor outlet and the temperature of cooling medium.Generally speaking, depend on existence and the temperature levels of heat exchanger, product gas obtains 100-440 DEG C, preferred 140-300 DEG C, the particularly preferably temperature of 170-240 DEG C in the upstream of quench inlet.The product gas entrance of quenching must be designed, make gas access place and just before deposit blocking minimize or prevent it.Product gas is contacted with cooling medium in the first quench cooling phase.Herein, cooling medium introduces to realize mixing with product gas is very effective by nozzle.Due to identical object, the internals that product gas passes through together with cooling medium such as other nozzle can be arranged in quench cooling phase.The coolant entrance that must design quenching makes the blocking of the deposit in coolant entrance region minimize or prevent it.

Generally speaking, product gas is cooled to 5-180 DEG C in the first quench cooling phase, is preferably cooled to 30-130 DEG C, be even more preferably cooled to 60-90 DEG C.The temperature of porch cooling medium can be 25-200 DEG C usually, preferred 40-120 DEG C, particularly preferably 50-90 DEG C.Pressure in first quench cooling phase not by any special restriction, but is generally 0.01-4 bar (table), preferred 0.1-2 bar (table), particularly preferably 0.2-1 bar (table).When in a large number high boiling point by-products produced be present in product gas time, the polymerization in high boiling point by-products produced or the deposition of solid by-product easily may occur due to high boiling point by-products produced in this operation.In cooling tower, cooling medium used usually circulates and makes may occur when carrying out the preparation of conjugated diene continuously to be blocked by solid sediment.Based on the mass flow of the butadiene represented with g/ hour, with l/h amount of the circulating cooling medium represented usually can for 0.0001-5 liter/gram, preferred 0.001-1 liter/gram, particularly preferably 0.002-0.2 liter/gram.

ODH reaction accessory substance as acetic acid, maleic anhydride etc. at cooling medium as the dissolving in water is carried out than easier at low ph values at a high ph.Dissolving due to accessory substance reduces the above-mentioned pH of such as water, by adding alkaline medium, pH is kept constant or raising.Generally speaking, the pH in the liquid phase of the first quench cooling phase remains on 2-14, preferred 3-13, particularly preferably 4-12.This value is more acid, must introduce fewer alkaline medium.More alkaline, the dissolving of some accessory substances is carried out goodly.But very high pH value causes accessory substance as CO ₂dissolve, therefore cause the consumption that alkaline medium is very high.In liquid phase, the temperature of cooling medium can be 27-210 DEG C usually, preferred 45-130 DEG C, particularly 55-95 DEG C.Because the secondary component load of cooling medium improved along with the time, the cooling medium of a part of load can be taken out from loop and be made by the cooling medium adding non-load the amount of circulation keep constant.The amount of discharging and the ratio of the amount added depend on the product gas temperature at the end of the vapor load of product gas and the first quench cooling phase.When cooling medium is water, the amount added in the first quench cooling phase is less than the amount of discharge usually.

Then can cooling the poor product gas flow containing secondary component feed in the second quench cooling phase.Among these, can it be again made to contact with cooling medium.

Generally speaking, product gas is cooled to 5-100 DEG C, preferably to 15-85 DEG C, even more preferably to 0-70 DEG C, until the gas vent of the second quench cooling phase.Cooling agent can with product gas countercurrent.In this case, the temperature of coolant entrance place coolant media can be 5-100 DEG C, preferred 15-85 DEG C, particularly 30-70 DEG C.Pressure in second quench cooling phase not by any special restriction, but is generally 0.01-4 bar (table), preferred 0.1-2 bar (table), particularly preferably 0.2-1 bar (table).In cooling tower, cooling medium used circulates usually, makes the obstruction that may occur when carrying out the preparation of conjugated diene continuously because solid sediment causes.Based on the mass flow of the butadiene represented with g/ hour, with l/h amount of the circulating cooling medium represented usually can for 0.0001-5 liter/gram, preferred 0.0001-1 liter/gram, particularly preferably 0.002-0.2 liter/gram.

ODH reaction accessory substance as acetic acid, maleic anhydride etc. at cooling medium as the dissolving in water is carried out than easier at low ph values at a high ph.Dissolving due to accessory substance reduces the above-mentioned pH of such as water, by adding alkaline medium, pH is kept constant or raising.Generally speaking, the pH in the liquid phase of the second quench cooling phase remains on 1-14, preferred 2-12, particularly preferably 3-11.This value is more acid, must introduce fewer alkaline medium.More alkaline, the dissolving of some accessory substances is carried out goodly.But very high pH value causes accessory substance as CO ₂dissolve, therefore cause the consumption that alkaline medium is very high.In liquid phase, the temperature of cooling medium can be 20-210 DEG C usually, preferred 35-120 DEG C, particularly 45-85 DEG C.Because the secondary component load of cooling medium improved along with the time, the cooling medium of a part of load can be taken out from loop and be made by the cooling medium adding non-load the amount of circulation keep constant.The amount of discharging and the ratio of the amount added depend on the product gas temperature at the end of the vapor load of product gas and the first quench cooling phase.When cooling medium is water, the amount added in the first quench cooling phase is greater than the amount of discharge usually.

In order to realize, product gas and cooling medium are extraordinary to be contacted, and internals can be present in the second quench cooling phase.This kind of internals comprises such as bubble cap tray, centrifugal plate and/or sieve plate, has structured packing, such as, has 100-1000m ²/ m ³specific area metallic plate filler as the tower of 250Y, and the tower with random filler.

The loop of two quench cooling phases can separate or be interconnected.The temperature required of recycle stream is arranged by suitable heat exchanger.

Being delivered to gas outflow pipeline for making liquid component from quenching to minimize, can suitable structural measure being carried out, such as, demister is installed.In addition, by other structural measure as the high boiling substance be not separated with product gas in quenching removes by gas scrubbing from product gas.This obtains normal butane, 1-butylene, 2-butylene, butadiene, possibility oxygen, hydrogen, steam and methane, ethane, ethene, propane and propylene, isobutene, oxycarbide and inert gas are retained in air-flow wherein on a small quantity.In addition, the trace high boiling component be not separated quantitatively in quenching can be retained in this product gas flow.

Subsequently the product gas flow from quenching is compressed at least one compression stage, cool subsequently, therefore condensation go out condensate stream retaining that at least one comprises water comprise normal butane, 1-butylene, 2-butylene, butadiene, may hydrogen, steam and a small amount of methane, ethane, ethene, propane and propylene, isobutene, oxycarbide and inert gas, may the air-flow of oxygen and hydrogen.Compression can be carried out in one or more stage.In a word, air-flow is compressed to the pressure of 3.5-20 bar (absolute pressure) from the pressure of 1.0-4.0 bar (absolute pressure).Be cooling stage after each compression stage, wherein air-flow be cooled to the temperature of 15-60 DEG C.Therefore, when the multistage is compressed, condensate stream can comprise multiple stream.Condensate stream comprises at least 80 % by weight usually, preferably at least 90 % by weight water, and comprises a small amount of low boilers, C further ₄hydrocarbon, oxide and oxycarbide.

Suitable compressor is such as turbo-compressor, rolling piston compressor and reciprocating-piston compressor.Compressor can be driven by such as motor, expander or gas turbine or steamturbine.The typical compression ratio (outlet pressure: inlet pressure) of every compressor stage depends on that structure type is 1.5-3.0.The heat exchanger that is cooled through of Compressed Gas carries out, and described heat exchanger can be configured to such as shell and tube exchanger, spiral heat exchanger or plate type heat exchanger.In heat exchanger, cooling agent used is cooling water or heat-transfer oil.In addition, the Air flow of pressure fan is preferably used.

To comprise butadiene, butylene, butane, inert gas and may oxycarbide, oxygen, hydrogen and low boiling hydrocarbon (methane, ethane, ethene, propane, propylene) and a small amount of oxygenate stream feed process further as initial stream.

Low boiling secondary component and product gas flow to be separated by conventional separation methods as distilled, film method, absorption or absorption carries out.

For any hydrogen comprised in separated product air-flow, product gas mixture can be made optionally such as in heat exchanger, after cooling, thoroughly and usually can be configured to the film of pipe by only molecular hydrogen.The molecular hydrogen separated so if necessary can at least in part in dehydrogenation or enter another purposes, such as, for producing electric energy in fuel tank.

Be included in carbon dioxide in product gas flow by CO ₂drechsel system is separated.Can be combustion phases separately before carbon dioxide washer, co selective oxidation be become carbon dioxide wherein.

In a preferred embodiment of the method, not condensable or low-boiling point gas component are separated by higher boiling absorbing medium as possible nitrogen as hydrogen, oxygen, oxycarbide, low boiling hydrocarbon (methane, ethane, ethene, propane, propylene) and inert gas in absorption/desorption circulation, obtain basic by C ₄the C of hydrocarbon composition ₄product gas flow.Generally speaking, C ₄product gas flow comprises at least 80 volume %, preferably at least 90 volume %, particularly preferably at least 95 volume %C ₄hydrocarbon, especially normal butane, 2-butylene and butadiene.

For this reason, after previous water removes, product gas flow is made to contact with inertia absorbing medium in the absorption stage and make C ₄hydrocarbon is absorbed in inertia absorbing medium, obtains being loaded with C ₄absorbing medium and the tail gas comprising residual gas component of hydrocarbon.In desorption phase, C ₄hydrocarbon again discharges from absorbing medium.

Absorption stage can carry out in any suitable absorption tower well known by persons skilled in the art.Absorb and carry out simply by absorbing medium by product gas flow.But it also can carry out in tower or in rotary absorber.Absorption can and flow, adverse current or cross-flow carry out.Absorb preferred adverse current to carry out.Suitable absorption tower is the plate column such as with bubble cap tray, centrifugal plate and/or sieve plate, and having structured packing such as specific area is 100-1000m ²/ m ³sheet metal filler as the tower of 250Y, and the tower with random filler.But trickling tower and spray column, graphite block absorber, surface absorber are as thick film absorber and film absorption device, and rotary column, scrubber, intersection sprayer-washer and rotary washer are also possible.

In one embodiment, the stream comprising butadiene, butylene, butane and/or nitrogen and possibility oxygen, hydrogen and/or carbon dioxide is fed in the lower area on absorption tower.In the upper area on absorption tower, introduce the stream comprising solvent and optional water.

C to be separated is generally for the inertia absorbing medium in the absorption stage ₄hydrocarbon mixture has the higher boiling non-polar solven of obviously larger than residual gas component to be separated solubility wherein.Suitable absorbing medium is suitable non-polar organic solvent, such as C ₈-C ₁₈aliphatic alkanes, or aromatic hydrocarbon, such as from alkane distillation middle oil fraction, toluene or there is the ether of bulky group, or the mixture of these solvents; Can to adding polar solvent as 1,2-repefral in these.Other absorbing mediums are benzoic ether and phthalic acid and straight chain C ₁-C ₈the ester of alkanol and heat-transfer oil are as biphenyl and diphenyl ether, its chlorinated derivatives and triaryl alkene.Applicable absorbing medium is preferably have the biphenyl of azeotropic composition and a mixture for diphenyl ether, such as commercially available this solvent mixture usually comprises the repefral of the amount of 0.1-25 % by weight.

Suitable absorbing medium is octane, nonane, decane, hendecane, dodecane, tridecane, the tetradecane, pentadecane, hexadecane, heptadecane and octadecane, or by obtaining in oil plant stream and comprising the cut of above-mentioned linear paraffinic hydrocarbons as key component.

In a preferred embodiment, paraffins mixture is as the tetradecane (industrial C ₁₄-C ₁₇cut) as absorption solvent.

At top, absorption tower, take out mainly comprise inert gas, oxycarbide, may butane, butylene as 2-butylene and butadiene, may oxygen, hydrogen and low boiling hydrocarbon (as methane, ethane, ethene, propane, propylene) and steam waste gas streams.This stream partly can be fed ODH reactor or O ₂remove in reactor.This such as can make the incoming flow of ODH reactor be adjusted to required C ₄hydrocarbon content.

C will be loaded with ₄the solvent stream of hydrocarbon is introduced in desorber.According to the present invention, all tower internal parts well known by persons skilled in the art are suitable for this object.In a method change programme, desorption procedure is undertaken by the decompress(ion) of loaded solvent and/or heating.Preferred method change programme is introduced by stripping stream and/or fresh stream introduced the bottom of desorption device.Poor containing C ₄the solvent of hydrocarbon can be used as during mixture feeds and be separated together with the steam (water) of condensation, makes water and separated from solvent.All devices well known by persons skilled in the art can be used for this object.In addition, can use and produce stripped vapor with the water of separated from solvent.

Preferred use 70-100 % by weight solvent and 0-30 % by weight water, particularly preferably 80-100 % by weight solvent and 0-20 % by weight water, particularly 85-95 % by weight solvent and 5-15 % by weight water.The absorbing medium regenerated in desorption phase was recycled in the absorption stage.

Being separated is not usually very completely, makes the type depending on separation, and on a small quantity or only trace other gas component, particularly high boiling hydrocarbon can be present in C ₄in product gas flow.The burden of processing step is subsequently also reduced by the reduction being separated the volume flow produced.

The basic C be made up of as 2-butylene and butadiene normal butane, butylene ₄product gas flow comprises 20-80 volume % butadiene, 20-80 volume % normal butane, 0-10 volume %1-butylene and 0-50 volume %2-butylene usually, and wherein total amount adds up to 100 volume %.In addition, a small amount of iso-butane can be comprised.

Subsequently can by C ₄product gas flow is separated into the stream be substantially made up of normal butane and 2-butylene and the stream comprising butadiene by extractive distillation.The basic stream be made up of normal butane and 2-butylene can be recycled to the C of ODH reactor whole or in part ₄in charging.Because the butylene isomer in this recycle stream is made up of 2-butylene substantially, and these 2-butylene usually than 1-butylene more slowly oxidative dehydrogenation become butadiene, this recycle stream can be made to stand method for catalytically isomerizing before in introducing ODH reactor.In this catalysis process, can arrange isomeric distribution, it is equivalent to the isomeric distribution be present in thermodynamic equilibrium.

Extractive distillation can such as " und Kohle-Erdgas-Petrochemie ", the 34th (8) volume, 343-346 page, or " Ullmanns der Technischen Chemie ", the 9th volume, 1975 the 4th edition, carry out described in 1-18 page.For this reason, C is made ₄product gas flow in extraction section with extractant, the contact of preferred 1-METHYLPYRROLIDONE (NMP)/aqueous mixtures.Extraction section configures to comprise column plate, random packing component or structured packing as the form of the scrubbing tower of internal part usually.It usually has 30-70 theoretical tray and makes to realize enough good centrifugation.Scrubbing tower preferably has the recirculating zone at the top at tower.This recirculating zone is used for being refluxed by liquid hydrocarbon and reclaiming the extractant comprised in the gas phase, overhead fraction condensation in advance for this reason.C in extractant and extraction section charging ₄the mass ratio of product gas flow is generally 10:1-20:1.Extractive distillation is preferably at 100-250 DEG C, and the particularly bottom temp of 110-210 DEG C, carries out under the pressure of the head temperature of 10-100 DEG C, particularly 20-70 DEG C and 1-15 bar, particularly 3-8 bar.Extraction distillation column preferably has 5-70 theoretical tray.

The extractant be applicable to is butyrolactone; nitrile is as acetonitrile, propionitrile, methoxypropionitrile; ketone is as acetone; furfural; the comparatively lower aliphatic acid acid amides of N-alkyl-replacement is as dimethyl formamide, DEF, dimethylacetylamide, diethyl acetamide, N-formyl-morpholine, and the cyclic amides (lactams) of N-alkyl-replacement is as N-alkyl pyrrolidone, especially 1-METHYLPYRROLIDONE (NMP).Usually, the cyclic amides compared with the sour acid amides of lower aliphatic or N-alkyl-replacement of alkyl-replacements is used.Particularly advantageously dimethyl formamide, acetonitrile, furfural and particularly NMP.

But, also these extractants can be used to each other, the mixture of such as NMP and acetonitrile, the mixture of these extractants and cosolvent and/or tertbutyl ether such as methyl tertiary butyl ether(MTBE), ethyl tert-butyl ether (ETBE), propyl group tertbutyl ether, normal-butyl tertbutyl ether or isobutyl group tertbutyl ether.Particularly suitable extractant is NMP, preferably as an aqueous solution, preferably has 0-20 % by weight water, particularly preferably has 7-10 % by weight water, particularly have 8.3 % by weight water.

Top product stream from extraction distillation column substantially comprises butane and butylene and a small amount of butadiene and takes out with gas or liquid form.Generally speaking, the stream be substantially made up of normal butane and 2-butylene comprises 50-100 volume % normal butane, 0-50 volume %2-butylene and other component of 0-3 volume % as iso-butane, isobutene, propane, propylene and C ₅ ⁺hydrocarbon.

In the bottom of extraction distillation column, obtain comprising extractant, water, butadiene and fraction butylene and butane stream and this is fed in destilling tower.Among this, obtain butadiene at top or as side-draw stream.Obtain in the bottom of destilling tower the stream comprising extractant and water, the composition wherein comprising the stream of extractant and water is equivalent to introduce the composition in extraction.The stream comprising extractant and water is preferably recycled in extractive distillation.

Extractant solution is transferred in desorption zone, there butadiene is desorbed from extraction solution.Desorption zone can such as to have 2-30, a preferred 5-20 theoretical tray and optionally have the scrubbing tower form configuration of recirculating zone of such as 4 theoretical trays.This recirculating zone is used for reclaiming by liquid hydrocarbon backflow the extractant comprised in the gas phase, and for this reason, overhead fraction is condensation in advance.Structured packing, column plate or random filler provide as internal part.Distillation, preferably at 100-300 DEG C, is carried out under the head temperature of the particularly bottom temp of 150-200 DEG C and 0-70 DEG C, particularly 10-50 DEG C.Pressure in destilling tower is preferably 1-10 bar.Generally speaking, low compared with extraction section pressure and/or higher pressure prevailing in desorption zone.

Needed for obtaining at the top of tower, product stream comprises 90-100 volume % butadiene, 0-10 volume %2-butylene and 0-10 volume % normal butane and iso-butane usually.For butadiene of purifying further, can carry out as further distillation described in the prior.

The present invention is set forth by following examples.

Embodiment

Catalyst synthesizes:

Prepare 2 kinds of solution A and B.

Solution A:

3200g water is put into 10 liters of Stainless steel basins.When being stirred by anchor agitator, 5.2g KOH solution (32 % by weight KOH) is added in the water originally loaded.Solution is heated to 60 DEG C.Then once add 1066g Ammoniun Heptamolybdate Solution ((NH through 10 minutes a little ₄) ₆mo ₇o ₂₄* 4H ₂o, 54 % by weight Mo).By other for gained suspension agitation 10 minutes.Solution B:

1771g cobalt nitrate (II) solution (12.3 % by weight Co) is put into 5 liters of Stainless steel basins and is heated to 60 DEG C, stirs (anchor agitator) simultaneously.Then once add 645g ferric nitrate (III) solution (13.7 % by weight Fe) through 10 minutes a little, keep this temperature simultaneously.The solution formed is stirred other 10 minutes.Then add 619g bismuth nitrate solution (10.7 % by weight Bi), keep this temperature simultaneously.After other 10 minutes of stirring, once add the chromic nitrate as solid (III) of 109g a little, and the dark red solution formed is stirred other 10 minutes.

The temperature of maintenance 60 DEG C while, solution B is pumped in solution A through 15 minutes by peristaltic pump.During adding and thereafter, stirred the mixture by super mixer (Ultra-Turrax).After interpolation completes, mixture is stirred other 5 minutes.

By gained suspension in from the spray dryer (shower nozzle No.FOA1, rotating speed: 25000rpm) of NIRO through 1.5 hours spraying dry.During this period the temperature of initial charge is remained on 60 DEG C.The gas inlet temperature of spray dryer is 300 DEG C, and gas outlet temperature is 110 DEG C.Gained powder has the granularity (d being less than 40 μm ₅₀).

Gained powder is mixed with 1 % by weight graphite, in the pressure system twice of 9 bar, and is pulverized by the sieve of the mesh with 0.8mm.Again comminution of material mixed with 2 % by weight graphite and by Kilian S100 tablet press machine, mixture suppressed to obtain 5 × 2 × 3mm (external diameter × internal diameter × length) ring.

By (500g) calcining in batches in from the convection furnace (model K, 750/2S, inner volume 55 liters) of Heraeus, DE of gained catalyst precarsor.For this reason, following program is used:

-in 72 minutes, be heated to 130 DEG C, keep 72 minutes

-in 36 minutes, be heated to 190 DEG C, keep 72 minutes

-in 36 minutes, be heated to 220 DEG C, keep 72 minutes

-in 36 minutes, be heated to 265 DEG C, keep 72 minutes

-in 93 minutes, be heated to 380 DEG C, keep 187 minutes

-in 93 minutes, be heated to 430 DEG C, keep 187 minutes

-in 93 minutes, be heated to 490 DEG C, keep 467 minutes

After calcining, obtain that there is chemistry metering Mo ₁₂co ₇fe ₃bi _0.6k _0.08cr _0.5o _xcatalyst.

By the granule grind into powder of calcining.

Carrier (having the steatite ring of 7 × 4 × 3mm (external diameter × internal diameter × length) size) is applied with precursor composition.For this reason, carrier is put in coating cylinder (2 liters of inner volumes, drum central axis and horizontal inclination angle=30 °).Cylinder is set to rotate (25rpm).About 32ml liquid adhesive (glycerine: the 1:3 mixture of water) is sprayed on carrier through about 30 minutes by the atomizer operated by compressed air (spray air: 500 standards l/h).Nozzle is installed in a certain way, makes atomizer cone in the first half of downward rolling portion, soak the carrier carried in cylinder.Introduced in cylinder by fine-powdered precursor composition by powder screw rod, wherein the interpolation point of powder is in downward rolling portion, but below atomizer cone.Powder is metered in a certain way, makes to obtain powder being uniformly distributed from the teeth outwards.After coating completes, by the gained coated catalysts in drying box at 300 DEG C dry 3 hours comprising precursor composition and carrier.

Reactor:

Dehydrogenation experiment is carried out in midget plant reactor.This midget plant reactor be have the length of 500cm and the internal diameter of 29.7mm salt bath reactor and there is the temperature sensor sheath that external diameter is 6mm.Catalyst is loaded by reaction tube.The long rear bed of the 10cm with the steatite ring of geometry 7mm × 4mm × 7mm (external diameter × internal diameter × length) comprising 60g rests on catalyst grid.The undiluted coated catalysts (bed height 384cm, 2552ml bed volume in reactor) that 2710g is of a size of the hollow circular cylinder form of 7mm × 4mm × 3mm (external diameter × internal diameter × length) after this.It is the long preparation of the 85cm with the steatite ring of size 7mm × 4mm × 7mm (external diameter × internal diameter × length) bed comprising 487g after this catalyst bed.

By the temperature T with 390 DEG C flowed around it _{salt bath}salt bath reaction tube is heated over the whole length.Amount to the 1-butylene of 8 volume %, cis-2-butene and Trans-2-butene, 2 volume % butane (normal butane and iso-butane), 8.5 volume % oxygen, 12 volume % water and 69.5 volume % nitrogen mixture be used as the starting gas mixture of reaction.Be 5520 standards l/h total gases by the air speed of reaction tube.Salt temperature is constant in 390 DEG C.Hot(test)-spot temperature average out to about 439 DEG C and be positioned at catalyst bed first three/place.The temperature-averaging of bed end is about 397 DEG C.

Pressure measxurement is at reactor inlet (p ₁) and reactor outlet (p ₂) place carries out.

In product gas flow, based on all butylene 1,3-butadiene yield and also formed based on the styrene, anthraquinone and the Fluorenone that represent with volume % of all butylene and pass through gas chromatography determination.The yield of component X calculates as follows:

Wherein [X] _in[X] _outbe respectively the volumetric concentration of component X at reactor inlet and reactor exit, Δ _volfor the Volume Changes factor, and [butylene] _inhave by reactor inlet place the volumetric concentration sum of butylene isomer.

The results are shown in table 1.

Table 1

As can be seen from Table 1, the formation of carbonaceous material precursor styrene, anthraquinone and Fluorenone is increased in 1. Palestine and Israels along with pressure and significantly improves.It is out-of-proportion for improving (12.5-21.2%), because the yield of butadiene only improves (4.6%) slightly.

Claims (16)

1. the catalyst that can be obtained by the catalyst precarsor comprising following component:

Comprise molybdenum and other metal of at least one and there is the catalytic activity poly-metal deoxide of general formula (I):

Mo ₁₂Bi _aFe _bCo _cNi _dCr _eX ¹ _fX ² _gO _x(I)，

Wherein variable has following implication:

X ¹=W, Sn, Mn, La, Ce, Ge, Ti, Zr, Hf, Nb, P, Si, Sb, Al, Cd and/or Mg;

X ²=Li, Na, K, Cs and/or Rb,

A=0.1-7, preferred 0.3-1.5;

B=0-5, preferred 2-4;

C=0-10, preferred 3-10;

d＝0-10；

E=0-5, preferred 0.1-2;

F=0-24, preferred 0.1-2;

G=0-2, preferred 0.01-1; And

The chemical valence of the element of oxygen and the number of abundance decision is different from during x=serves as reasons (I),

Wherein catalyst has hollow cylinder shape, wherein internal diameter be external diameter 0.2-0.8 doubly and length be the 0.5-2.5 of external diameter doubly, and catalyst precarsor does not comprise any pore-forming agent.

2. catalyst according to claim 1, it is full active catalyst.

3. catalyst according to claim 1, it is for having the coated catalysts of carrier (a) and shell (b).

4. catalyst as claimed in one of claims 1-3, it has the size that external diameter × internal diameter × length is (4-10mm) × (2-8mm) × (2-10mm).

5. catalyst according to claim 4, it has the size that external diameter × internal diameter × length is (6-8mm) × (3-5mm) × (2-6mm).

6. catalyst according to claim 3, wherein carrier (a) has the size that external diameter × internal diameter × length is (4-10mm) × (2-8mm) × (2-10mm).

7. catalyst according to claim 6, wherein carrier (a) has the size that external diameter × internal diameter × length is (6-8mm) × (3-5mm) × (2-6mm).

8., according to the catalyst of claim 6 or 7, its mesochite (b) has the layer thickness D of 50-600 μm.

9. catalyst as claimed in one of claims 1-8, the poly-metal deoxide wherein comprising molybdenum and other metal of at least one has general formula (Ia):

Mo ₁₂Bi _aFe _bCo _cNi _dCr _eX ¹ _fX ² _gO _y(Ia),

Wherein:

X ¹=Si and/or Al,

X ²=Li, Na, K, Cs and/or Rb,

0.2≤a≤1，

0.5≤b≤10，

0≤c≤10，

0≤d≤10，

2≤c+d≤10

0≤e≤2，

0≤f≤10，

0≤g≤0.5，

The number that y=is determined by the chemical valence of element and abundance that are different from oxygen in (1a) is to realize neutral charge.

10. n-butene oxidative dehydrogenation is become the method for butadiene, wherein mix with oxygen-containing gas the starting gas mixture comprising n-butene be incorporated in fixed bed reactors contacting with the coated catalysts as claimed in one of claims 1-10 arranged with stationary catalyst bed at the temperature of 220-490 DEG C.

11. methods according to claim 10, wherein fixed bed reactors are fixed-bed tube reactor or fixed bed shell-tube type reactor.

12. according to the method for claim 10 or 11, and the starting gas mixture wherein comprising n-butene is obtained by the Non-oxidative dehydrogenation of normal butane.

13., according to the method for claim 10 or 11, wherein comprise the starting gas mixture of n-butene by the C from naphtha cracker ₄cut obtains.

14. according to the method for claim 10 or 11, and the starting gas mixture wherein comprising n-butene is obtained by the dimerization of ethene.

15. according to the method for claim 10 or 11, and the starting gas mixture wherein comprising n-butene is obtained by fluid catalytic cracking (FCC).

N-butene oxidative dehydrogenation is being become the purposes in butadiene by 16. catalyst as claimed in one of claims 1-9.