CN102728371A - High cerium content alkylaromatic dehydrogenation catalyst and preparation method thereof - Google Patents

Abstract

The invention relates to an alkylaromatic dehydrogenation catalyst, mainly solving the problem of low activity of an alkylaromatic dehydrogenation catalyst at high space velocity existing in the prior art. According to the invention, by selecting an appropriate cerium source, simultaneously raising the cerium oxide content in the catalyst to more than 14%, and conducting premixing and aging in the preparation process of the catalyst, the problem is well solved, and the prepared catalyst can be used in the industrial production of alkoxy and alkenyl aromatic hydrocarbons.

Description

A kind of high cerium content Alkylarylhydrocarbondehydrogenating dehydrogenating catalyst and manufacturing approach thereof

Technical field

The present invention relates to a kind of Alkylarylhydrocarbondehydrogenating dehydrogenating catalyst that contains cerium, particularly about preparing cinnamic dehydrogenation.

Background technology

Industrial production of styrene more than 85% is undertaken by the direct catalytic dehydrogenation process of ethylbenzene at present.The basic composition of used catalyst comprises major catalyst, co-catalyst and some perforating agents etc.Early stage catalyst is the Fe-K series catalysts that contains Cr, like U.S. Patent No. US4467046, US4684619 and European patent EP 0195252A2 etc.Though such activity of such catalysts is better with stability, owing to more or less have the oxide of Cr in forming, thereby can cause certain environment to pollute in Preparation of Catalyst, operation and the dead catalyst processing procedure.The later stage people success seventies in last century developed Fe-K-Ce-Mo series; With Ce, Mo replaced C r; Activity of such catalysts and stability are all increased, like U.S. Pat 3904552, US5190906, US4804799, world patent WO09839278A1 etc.The service life of this type catalyst, generally about 2 years, the styrene device production scale of use was generally at 8～200,000 tons/year, and minority is at 500,000 tons/year, and generally producing 10,000 tons of styrene needs 0.5 ton of catalyst, and the air speed of device is generally at 0.2～0.5h ^-1

In order to control the manufacturing cost of catalyst, the content of catalyst middle rare earth elemental cerium is generally below 10% in the industry.In order to improve the performance of catalyst, people often seek to add other multiple co-catalysts except that cerium.Like patent CN00116523.2, cerium content is 3～10%, and the multiple co-catalyst that adds simultaneously among the Ti Zr W V Ni Co Mg Ca Al Ge Se Bi P B Sn Pb Si improves activity of such catalysts.Patent CN01126343 has reported a kind of catalyst, and its cerium content is 4～8%, adds Sr simultaneously and reaches higher activity.Patent CN01126344.X has reported a kind of catalyst, and its cerium content is 4～8%, adds the performance that 0.5～2.0% Hf improves catalyst simultaneously.Patent CN200710039046.4 has reported a kind of catalyst, and its cerium content is 6～11%, adds Ni simultaneously and reaches preferable performance with other rare earth elements.All do not relate to the catalytic performance of catalyst under the high-speed condition in the above technical scheme.

Along with the continuous increase of world market to the styrene demand, the styrene device scale on new is also increasing, is 650,000 tons/year like Shanghai match section unit scale; Dagu, Tianjin is 500,000 tons/year etc.; And old device will improve production capacity, can improve the conversion ratio of catalyst on the one hand, improves cinnamic yield; But the as easy as rolling off a log polymerization of the styrene of high concentration; So the styrene device conversion ratio generally is controlled at below 65% in the industry, can improve the treating capacity of device on the other hand, increase the air speed of charging.How keep existing apparatus do not do change situation under, through improving the treating capacity of device, thereby reach the purpose that improves production capacity, for the old styrene device crucial meaning of having increased economic efficiency.

Summary of the invention

The technical problem that the present invention mainly solves is Alkylarylhydrocarbondehydrogenating dehydrogenating catalyst lower problem of catalyst activity under the high-speed condition, and a kind of new Alkylarylhydrocarbondehydrogenating dehydrogenating catalyst and preparation method thereof is provided.When using high cerium content alkyl dehydrogenation of the present invention, under the high-speed condition, still keep higher activity, raising device capbility that can be by a relatively large margin.

For solving the problems of the technologies described above, the technical scheme that the present invention adopts is following: a kind of alkyl aromatic dehydrogenation and preparation method thereof, and catalyst comprises following composition in weight percent:

A) 50～76% Fe ₂O ₃

B) 10～20% K ₂O

C) 14～35% CeO ₂

D) 0.5～5% MoO ₃

Wherein the content of cerium is higher than the catalyst of present commercial Application greater than 14%, and at least a kind in cerium oxalate, cerous nitrate, cerous carbonate, the hydroxide cerous carbonate is adopted in the cerium source.

In the technique scheme, the catalyst preferred version is that catalyst also contains 0.005～5% the oxide or the compound that are selected from least a metal among the Mg Ca Ti Zr V Ni Nb Cr Mn La Pb Co Zn B Pt Pd Au Al Si Ge Sn BiSb Pr Nd Sm by weight percentage.

K in the technique scheme ₂O is with K ₂CO ₃Form add Fe ₂O ₃By iron oxide red (Fe ₂O ₃) or iron oxide red and iron oxide yellow (Fe ₂O ₃.H ₂O) mixture is formed, and the weight ratio between the two is Fe ₂O ₃.H ₂O: Fe ₂O ₃=0～0.5: 1.

The Preparation of catalysts method adopts and at first iron oxide and cerium source is carried out premixed in the such scheme, carries out ageing after mixing and handles.Digestion time is 0～24 hour; The premix that ageing is good and other co-catalyst component dry mixed of residue 0.5～4 hour; Adding proper amount of deionized water mixed 0.5～4 hour; Be cut into sizeable particle then, through 60～150 ℃ of dryings, then 250～900 ℃ of calcinings 6～18 hours.

The used raw material of catalytic component of the present invention is following:

Fe ₂O ₃Be made up of iron oxide red and iron oxide yellow, potassium adds with the form of potash, and cerium adds with a kind of form in cerium oxalate, cerous nitrate, cerous carbonate, the hydroxide cerous carbonate at least, and molybdenum adds with the form of other co-catalysts with oxide, hydroxide or slaine.

Comprise perforating agent in the catalyst of the present invention, its consumption is 1～5% of a catalyst weight, can choose one or several from graphite, polystyrene microsphere, methylcellulose etc.

The dehydrogenation that the present invention is made, can be applicable to ethylbenzene under certain condition fully, diethylbenzene, and methyl-ethyl benzene is made styrene, divinylbenzene and methyl styrene.

Make catalyst as stated above and in the isotherm formula fixed bed, carry out activity rating, as far as the ethyl benzene dehydrogenation preparation of styrene activity rating, the summary process is following:

Deionized water and ethylbenzene are imported preheating mixer through measuring pump respectively, and preheating gets into reactor after being mixed into gaseous state, and reactor adopts the heating wire heating, makes it to reach predetermined temperature.Reactor inside diameter is 1 " stainless steel tube, interiorly load 100 milliliters, particle diameter is 3 millimeters a catalyst.Behind water condensation, analyzing it with gas chromatograph by the reactant of reactor outflow forms.

Conversion of ethylbenzene and selectivity of styrene calculate by following formula:

Ethylbenzene concentration before conversion of ethylbenzene %=(ethylbenzene concentration before the reaction-reaction back ethylbenzene concentration)/reaction

The concentration of styrene that selectivity of styrene %=generates/(concentration of styrene before the reaction-reaction back concentration of styrene)

The present invention selects suitable cerium source; Improve the content of cerium; At first carry out premixed and ageing through iron oxide with the cerium source; Cerium is increased in the adsorption strength and the quantity of iron oxide surface greatly, strengthened the electron exchange quantity and the ability of catalyst activity phase Fe3+ surface and co-catalyst cerium, can make more ethylbenzene in catalyst surface moment conversion.When the ethylbenzene air speed increases, still can it be transformed, thereby improve the production capacity of installing by a relatively large margin.In water/ethylbenzene weight ratio is 2.0, and reaction temperature is under 620 ℃ the condition, and the ethylbenzene air speed increases by 50%, and its conversion ratio just slightly descends, and has obtained better technical effect.

Through embodiment further elaboration is done in invention below:

The specific embodiment

Embodiment 1

400 gram iron oxide reds, 56 gram iron oxide yellows and 191.5 gram cerium oxalates were mixed in kneader 2 hours; At room temperature display after 5 hours and to add 106 gram potash, 21 gram calcium hydroxides, 19 gram molybdenum oxides, 5 gram titanium oxide and 21 gram carboxymethyl celluloses and mix after 2 hours; Add small quantity of deionized water, process toughness, be fit to the dough thing of extrusion, becoming diameter through extruded moulding, pelletizing is 3 millimeters, long 5～7 millimeters particle; Put into baking oven in 90～120 ℃ of dryings 4 hours; Place muffle furnace 300 ℃～700 ℃ following roastings 10 hours then, 770 ℃ of following roastings 4 hours, cooling obtained finished catalyst naturally.

With 100 milliliters of catalyst reactor of packing into, at normal pressure, 620 ℃ of water than 2.0 liquid air speed 1.0h ^-1And 1.5h ^-1Condition under carry out active testing, test result is listed in table 1

Embodiment 2

Method according to instance 1 prepares catalyst, and different is with 600 gram iron oxide reds, 110 gram iron oxide yellows, 375.5 gram cerous carbonates, 210 gram potash, 21 gram calcium carbonate, 5 gram ammonium molybdates, 5 gram magnesia and 35 gram graphite.Assembly time is 6 hours.

According to the evaluating catalyst method of instance 1, test result is listed in table 1.

Embodiment 3

Method according to instance 1 prepares catalyst, and different is with 300 gram iron oxide reds, 50 gram iron oxide yellows, 150 gram potash, 126.7 gram basic carbonate ceriums, 4 gram magnesia, 5 gram ammonium molybdates, 2 gram lead oxide and 21 gram carboxymethyl celluloses.Assembly time is 8 hours.70～120 ℃ dry 3 hours down, place muffle furnace, when 340～800 ℃ of roastings 7 are slight, after 2 hours, lower the temperature naturally 800 ℃ of following roastings, obtain finished catalyst.

According to the evaluating catalyst method of instance 1, test result is listed in table 1.

Embodiment 4

Method according to embodiment 1 prepares catalyst, and different is with 400 gram iron oxide reds, 60 gram iron oxide yellows, 20 gram cerium oxalates, 213.6 gram cerous nitrates, 150 gram potash, 10 gram calcium oxide, 5 gram molybdenum oxides, 6 gram magnesia, 0.5 gram vanadium oxide, 1 gram manganese oxide, 35 gram carboxymethyl celluloses.Assembly time is 10 hours.

According to the evaluating catalyst method of instance 1, test result is listed in table 1.

Embodiment 5

Method according to embodiment 1 prepares catalyst, and different is with 320 gram iron oxide reds, 78 gram iron oxide yellows, 103 gram potash, 348.5 gram cerous nitrates, 3 gram zinc oxide, 3 gram molybdenum oxides, 2 gram tin oxide, 20 gram carboxymethyl celluloses.

According to the evaluating catalyst method of instance 1, test result is listed in table 1.

Embodiment 6

Method according to embodiment 1 prepares catalyst, and different is with 400 gram iron oxide reds, 10 gram iron oxide yellows, 160 gram potash, 95 gram cerium oxalates, 186 gram basic carbonate ceriums, 3 gram cobalt oxides, 10 gram molybdenum oxides and 40 gram carboxymethyl celluloses.

According to the evaluating catalyst method of instance 1, test result is listed in table 1.

The weight percent of gained catalyst is formed as follows:

Comparative example 1

Method according to embodiment 1 prepares catalyst, and except that cerium, it is identical with embodiment 1 that all catalyst are formed additions, and the addition of different is cerium oxalate is 110 to restrain.

According to the evaluating catalyst method of instance 1, test result is listed in table 1.

Comparative example 2

Method according to embodiment 2 prepares catalyst, and except that cerium, all catalytic component additions are identical with embodiment 2, and different is that the cerium source of adopting is a cerium oxide, and addition is 280.9 grams.

According to the evaluating catalyst method of instance 1, test result is listed in table 1.

Comparative example 3

All components adds according to the inventory of embodiment 3, adopts same cerium source.Different is not adopt ageing to handle in the Preparation of catalysts process, and all components adds simultaneously and mixes.

According to the evaluating catalyst method of instance 1, test result is listed in table 1.

Comparative example 4

Method according to embodiment 4 prepares catalyst, and except that cerium, all catalytic component additions are identical with embodiment 4, and different is that the cerium source of adopting is the oxygen cerium oxide, and addition is 108 grams.

According to the evaluating catalyst method of instance 1, test result is listed in table 1.

Comparative example 5

Method according to embodiment 5 prepares catalyst, and all catalytic component additions are identical with embodiment 5, sintering temperature is under 950 ℃ condition roasting that different is 2 hours.

According to the evaluating catalyst method of instance 1, test result is listed in table 1.

The weight percent of gained catalyst is formed as follows:

The performance comparison of table 1 catalyst

Above embodiment explanation; Through selecting suitable cerium source; The content of the cerium oxide in the catalyst is brought up to more than 14%; In the Preparation of catalysts process, adopt premixed and carry out the ageing processing, can effectively improve activity of such catalysts, particularly can improve the activity of catalyst under high-speed.In the styrene commercial production, reactor is not done change, raising output that just can be by a relatively large margin.

Claims (8)

1. an alkyl aromatic compound dehydrogenation comprises 1 by weight percentage) 50～76% Fe ₂O ₃2) 10～20% K ₂O; 3) 14～35% CeO ₂4) 0.5～5% MoO ₃It is characterized in that CeO in the catalyst ₂Content more than 14%, be higher than in the present industry the generally catalyst of operation, at least a kind in cerium oxalate, cerous nitrate, cerous carbonate, the hydroxide cerous carbonate is adopted in the cerium source.

2. the alkyl aromatic dehydrogenation of stating according to claim 1 is characterized in that CeO by weight percentage ₂Consumption be 17～25%.

3. alkyl-aromatic compounds dehydrogenation according to claim 1 is characterized in that Fe ₂O ₃By iron oxide red (Fe ₂O ₃) or iron oxide red and iron oxide yellow (Fe ₂O ₃.H ₂O) mixture is formed, and the weight ratio between the two is Fe ₂O ₃.H ₂O: Fe ₂O ₃=0～0.5: 1.

4. alkyl-aromatic compounds dehydrogenation according to claim 1 is characterized in that potassium compound is a potash.

5. alkyl-aromatic compounds dehydrogenation according to claim 1 is characterized in that also containing the oxide or the compound that are selected from least a metal among the Mg Ca Ti Zr V Ni Nb Cr Mn La Pb Co Zn B Pt PdAu Al Si Ge Sn Bi Sb Pr Nd Sm of 0.005～5% weight.

6. Preparation of catalysts method according to claim 1: at first iron oxide and cerium source are carried out premixed, carry out ageing after mixing and handle.

7. Preparation of catalysts method according to claim 6 was with pre-composition ageing at room temperature 0～24 hour.

8. Preparation of catalysts method according to claim 1: the premix that ageing is good and other co-catalyst component dry mixed of residue 0.5～4 hour; Adding proper amount of deionized water mixed 0.5～4 hour; Be cut into sizeable particle then; Through 60～150 ℃ of dryings, then 250～900 ℃ of calcinings 6～18 hours.