CN103028419A - Catalyst for low-water ratio ethylbenzene dehydrogenation - Google Patents

Abstract

The invention relates to a catalyst for low-water ratio ethylbenzene dehydrogenation, which mainly solves the problem that in the prior art, low-potassium catalyst has poor stability under the condition of low-water ratio. The invention adopts the technical scheme that ferrate is added into a ferrum-potassium-cerium-tungsten-magnesium catalytic system, so that the problem is well solved. The catalyst can be applied in industrial production of styrene prepared through ethylbenzene dehydrogenation under the condition of low-water ratio.

Description

The catalyst of low-water ratio ethylbenzene dehydrogenation

Technical field

The present invention relates to a kind of production of phenylethylene catalyst by low-water ratio ethylbenzene dehydrogenation.

Background technology

The main reaction of ethylbenzene dehydrogenation is C ₆H ₅-C ₂H ₅→ C ₆H ₅CH=CH ₂+ H ₂+ 124KJ/mol.From thermodynamics, it is favourable to balance to reduce the ethylbenzene dividing potential drop, and therefore industrial common adding water vapour impels reaction to move to the product direction.Dehydrogenation of ethylbenzene to styrene technology latest development trend is to reduce raw materials consumption and improve efficiency.The latent heat of vaporization of water is very large, and the production of styrene process consumes a large amount of superheated vapours as the dehydrogenation medium so that this process energy consumption is large, production cost high.Exploitation be applicable to that water ratio in the isotherm formula fixed bed is lower than 1.8 (weight) thus low water than catalyst reduce commercial plant operation water than become styrene device, particularly large-scale styrene device in the urgent need to.

Industrial dehydrogenation of ethylbenzene to styrene generally adopts be take iron oxide as main active component, potassium oxide is the Fe-series catalyst of main co-catalyst, usually potassium content is greater than 15%, but potassium washes away lower easy loss and migration at high-temperature water vapor, affect catalyst from power of regeneration and stability, realize that 10% left and right sides low potassium content is the main flow of catalyst for phenylethylene dehydrogenation exploitation.It is generally accepted that potash is the most effective anti-carbon deposit auxiliary agent, the operation under low water ratio of low potassium catalyst, active phase KFeO ₂With storage potassium KFe mutually ₁₁O ₁₇Be reduced easily, therefore poor stability must manage to strengthen the ability of hanging down the anti-low water ratio of potassium catalyst.

To this, according to related documents report up to now, people had done a lot of the trial.After European patent 0177832 has been reported the magnesia that adds 1.8～5.4% (weight) in catalyst, be lower than under 2.0 (weight) at the water ratio and show preferably stability, but the potassium content of this catalyst is higher, greater than 20%.Reported adding Multimetal oxide and Ludox in the Fe-K-Cr system such as ZL95111761.0, the catalyst that makes is suitable for low water than lower operation, but the Cr that this catalyst contains contaminated environment, has been eliminated.

Along with the maximization of styrene device scale, energy-conservationly seem more and more important.Therefore, the service condition of dehydrogenation is done small improvement, need not change any equipment, need not increase investment, just can make manufacturing enterprise obtain huge economic benefit.Develop and a kind ofly be suitable for low water than the low potassium catalyst that moves under the condition, be the direction that the researcher makes great efforts always.

Summary of the invention

Technical problem to be solved by this invention is that the low potassium catalyst that exists in the conventional art is in the low water problem poorer than condition stability inferior, a kind of catalyst of new low-water ratio ethylbenzene dehydrogenation is provided, and this catalyst is used for the ethyl benzene dehydrogenation preparation of styrene reaction and has the low water characteristics better than condition stability inferior.

In order to solve the problems of the technologies described above, the technical solution used in the present invention is as follows: a kind of catalyst of low-water ratio ethylbenzene dehydrogenation comprises following component by weight percentage:

(a) 69～81% Fe ₂O ₃

(b) 4～9% K ₂O;

(c) 6～11% CeO ₂

(d) 1～5% WO ₃

(e) 0.5～5% MgO;

(f) 1～4% ZnO;

(g) 0～4% binding agent, binding agent is selected from a kind of of kaolin, diatomite or cement;

Wherein 2～10% of the iron oxide weight consumption derive from zinc ferrite.

In the technique scheme, by weight percentage, Fe ₂O ₃Be comprised of iron oxide red and iron oxide yellow, its proportioning is Fe ₂O ₃: Fe ₂O ₃H ₂O=2.5～4.5: 1.By weight percentage, preferred version is that 3～8% of iron oxide weight consumption derives from zinc ferrite.

The used raw material of the catalyst component that the present invention relates to is as follows:

Fe ₂O ₃Add with iron oxide red, iron oxide yellow and zinc ferrite form; Used K adds with the potash form; Used Ce adds with cerium oxide, cerium hydroxide or cerium salt form; Used W adds with its salt or oxide form; Used Mg adds with oxide, hydroxide or magnesium salts form; Used Zn adds with the zinc ferrite form; Remaining element adds with oxide form.In preparation process of the present invention, except the catalyst body composition, also should add perforating agent, perforating agent can be selected from graphite, polystyrene microsphere or sodium carboxymethylcellulose, and its addition is 2～6% of total catalyst weight.

Method for preparing catalyst of the present invention is as follows:

Will be by Fe, K, Ce, W, Mg and the ZnFe of proportioning weighing ₂O ₄And after the binding agent of other catalytic component that need to add and non-imposed adding and perforating agent mix, add the water that accounts for catalyst raw material gross weight 15～35%, mix again, through extrusion, drying, pelletizing becomes 3 millimeters of diameters, long 5～8 millimeters particle, in 2～4 hours, 80 ℃～150 ℃ dryings of 40 ℃～70 ℃ dryings 0.5～4 hour, then 200 ℃～400 ℃ lower roastings 0.5～4 hour, 600 ℃～900 ℃ lower roastings 2～4 hours, obtain finished catalyst again.

The catalyst that makes as stated above carries out activity rating in the isotherm formula fixed bed, for the catalyst for preparing phenylethylene from dehydrogenation of ethylbenzene activity rating, process is summarized as follows:

Deionized water and ethylbenzene are inputted preheating mixer through measuring pump respectively, and preheating enters reactor after being mixed into gaseous state, and reactor adopts electric-heating-wire-heating, makes it to reach predetermined temperature.Reactor inside diameter is 1 " stainless steel tube, the catalyst of 100 milliliters of interior fillings, 3 millimeters of particle diameters.Analyzing it with gas chromatograph by the reactant of reactor outflow behind water condensation forms.

Conversion of ethylbenzene, selectivity of styrene calculate as follows:

The present invention can Effective Raise active phase KFeO by add zinc ferrite in iron-potassium-cerium-tungsten-magnesium catalyst system and catalyzing ₂With storage potassium KFe mutually ₁₁O ₁₇Resistance to reduction, greatly delayed the loss speed of potassium in the ethylbenzene catalytic dehydrogenation course of reaction, obviously improved low potassium catalyst at low water than the stability under the condition, use the catalyst of the present invention's preparation to carry out activity rating at the isotherm formula fixed bed, normal pressure, liquid air speed 1.0 hours ^-1, 620 ℃, water check and rate than being reduced under 40% to 1.2 (weight) condition by common 2.0 (weight), move after 500 hours conversion ratio substantially constant, still up to 74.1%, selectively remain on 94.5%, obtained preferably technique effect.

The present invention is further elaborated below by embodiment.

The specific embodiment

[embodiment 1]

320.0 gram iron oxide reds, 120.0 gram iron oxide yellows, 68.0 gram potash, 38.8 gram cerium oxide, 16.0 gram ammonium tungstates, 8.8 gram magnesium hydroxides, 32.5 gram zinc ferrites and 20.0 gram sodium carboxymethylcelluloses were stirred in kneader 1.5 hours, add deionized water, mixed and stirred 0.5 hour, take out extrusion, be extruded into the particle of 3 millimeters of diameters, 5～8 millimeters of length, put into baking oven, 60 ℃ were dried by the fire 2 hours, 120 ℃ were dried by the fire 3 hours, then place muffle furnace, in 300 ℃ of roastings 2 hours, 800 ℃ of roastings obtained finished catalyst in 2.5 hours.

With 100 milliliters of catalyst reactor of packing into, normal pressure, liquid air speed 1.0 hours ^-1, 620 ℃, water are than carrying out activity rating under (weight) 1.2 conditions, evaluation result is listed in table 2.

[embodiment 2]

Press the method Kaolinite Preparation of Catalyst of embodiment 1, difference is with 370.0 gram iron oxide reds, 85.0 gram iron oxide yellows, 34.0 gram potash, 72.4 gram cerium oxalates, 8.7 gram tungsten oxides, 41.5 gram magnesium carbonate, 38.0 gram zinc ferrites and 30.6 gram graphite.

Appreciation condition by embodiment 1 carries out activity rating, and evaluation result is listed in table 2.

[embodiment 3]

Press the method Kaolinite Preparation of Catalyst of embodiment 1, difference is with 310.0 gram iron oxide reds, 100.0 gram iron oxide yellows, 56.0 gram potash, 82.0 gram cerous carbonates, 25.0 gram ammonium tungstates, 24.2 gram magnesia, 50.1 zinc ferrites and 37.5 gram polystyrene microspheres.

Appreciation condition by embodiment 1 carries out activity rating, and evaluation result is listed in table 2.

[embodiment 4]

Press the method Kaolinite Preparation of Catalyst of embodiment 1, difference is with 350.0 gram iron oxide reds, 100.0 gram iron oxide yellows, 48.0 gram potash, 112.5 gram cerium oxalates, 30.5 gram ammonium tungstates, 6.9 gram magnesium hydroxides, 42.1 gram zinc ferrites and 19.0 gram graphite.

Appreciation condition by embodiment 1 carries out activity rating, and evaluation result is listed in table 2.

[embodiment 5]

Press the method Kaolinite Preparation of Catalyst of embodiment 1, difference is with 330.0 gram iron oxide reds, 130.0 gram iron oxide yellows, 69.1 gram potash, 109.9 gram cerium oxalates, 28.5 gram ammonium tungstates, 20.1 gram magnesia, 3.0 gram cupric oxide, 23.1 gram zinc ferrites and 25.0 gram sodium carboxymethylcelluloses.

Appreciation condition by embodiment 1 carries out activity rating, and evaluation result is listed in table 2.

[embodiment 6]

Press the method Kaolinite Preparation of Catalyst of embodiment 1, difference is with 350.0 gram iron oxide reds, 95.0 gram iron oxide yellows, 75.0 gram potash, 82.0 gram cerous carbonates, 23.5 gram ammonium tungstates, 28.4 gram magnesia, 42.4 gram zinc ferrites and 29.6 gram polystyrene microspheres.

Appreciation condition by embodiment 1 carries out activity rating, and evaluation result is listed in table 2.

[embodiment 7]

Press the method Kaolinite Preparation of Catalyst of embodiment 1, difference is with 348.0 gram iron oxide reds, 100.0 gram iron oxide yellows, 48.0 gram potash, 88.0 gram cerium oxalates, 30.5 gram ammonium tungstates, 5.9 gram magnesia, 39.6 gram zinc ferrites, 17.8 gram cement and 21.5 gram graphite.

Appreciation condition by embodiment 1 carries out activity rating, and evaluation result is listed in table 2.

[comparative example 1]

Press the method Kaolinite Preparation of Catalyst of embodiment 1, difference is not add zinc ferrite.

Appreciation condition by embodiment 1 carries out activity rating, and evaluation result is listed in table 2.

[comparative example 2]

Press the method Kaolinite Preparation of Catalyst of embodiment 2, difference is to add 29.5 gram cement, does not add zinc ferrite.

Appreciation condition by embodiment 1 carries out activity rating, and evaluation result is listed in table 2.

[comparative example 3]

Press the method Kaolinite Preparation of Catalyst of embodiment 1, difference is with 360.0 gram iron oxide reds, 90.0 gram iron oxide yellows, 75.0 gram potash, 56.9 gram cerium oxide, 20.5 gram ammonium tungstates, 29.4 gram magnesium hydroxides, 67.3 gram zinc ferrites, 3.0 gram cupric oxide, 15.1 gram cement and 30.3 gram polystyrene microspheres.

Appreciation condition by embodiment 1 carries out activity rating, and evaluation result is listed in table 2.

The weight percent of gained catalyst is composed as follows:

The weight percent of table 1 catalyst forms

The contrast of table 2 catalyst performance

Above embodiment explanation, in iron-potassium-cerium-tungsten-magnesium catalyst system and catalyzing, add zinc ferrite, prolonged low potassium catalyst at low water than the service life under the condition, have significant energy-saving effect, can be used in the low industrial production of water than ethyl benzene dehydrogenation preparation of styrene under the condition.

Claims (2)

1. the catalyst of a low-water ratio ethylbenzene dehydrogenation comprises following component by weight percentage:

(a) 69～81% Fe ₂O ₃

(b) 4～9% K ₂O;

(c) 6～11% CeO ₂

(d) 1～5% WO ₃

(e) 0.5～5% MgO;

(f) 1～4% ZnO;

(g) 0～4% binding agent, binding agent is selected from a kind of of kaolin, diatomite or cement;

Wherein 2～10% of the iron oxide weight consumption derive from zinc ferrite.

2. the catalyst of described low-water ratio ethylbenzene dehydrogenation according to claim 1 is characterized in that by weight percentage 3～8% of iron oxide weight consumption derives from zinc ferrite.