The method of dehydrogenation of ethylbenzene to styrene

 

Use: preparation of hydrocarbons. Essence: carry out the dehydrogenation of ethylbenzene in the system containing a reactor with a fluidized bed and the regenerator, using a catalyst based on iron oxide deposited on a modified silicon aluminum oxide and containing promoters, representing an additional metal oxides. Effect: simplified technology. 17 C.p. f-crystals, 3 tab., 1 Il.

The invention relates to a method for dehydrogenation of ethylbenzene to styrene in a system containing a reactor with a fluidized bed and the regenerator, in the presence of a catalyst based on iron oxide and promoters selected, for example, metal oxides such as oxides of alkali metals, oxides of alkaline-earth metals and/or metal oxides of the lanthanides group, plotted on the modified alumina.

Styrene is an important intermediate product that can be used to obtain plastics and rubbers.

More precisely, styrene is used to produce polystyrene (crystals of General purpose polystyrene, high impact polystyrene, expandable polystyrene), Acrylonitrile copolymers, styrene and butadienestyrene ethylbenzene (EB) to styrene has a number of distinctive features, you need to consider in the flowsheet.

The first one lies in the fact that the reaction is controlled by thermodynamic equilibrium and, consequently, the transformation of one run of the reaction is not complete. The degree of dehydrogenation increases with the temperature and the decrease in the total pressure, while the reaction at constant pressure with increasing volume. Therefore, in order to achieve economically acceptable degree of conversion it is necessary to conduct the reaction at a temperature in the range from 540 to 630oC.

However, high temperatures stimulate the occurrence of side reactions, which are characterized by higher activation energy than the reaction activation energy of dehydrogenation. As a result, along with the main product formed more or less significant amounts of by-products, mainly toluene, benzene, coke and light products.

Therefore, it is necessary to use a catalyst that promotes the reaction towards the desired product.

Another important feature lies in the fact that the reaction is extremely endothermic, while thermal effect of the reaction is equal to 28 kcal/mol stenoleptura, at which the heat transfer is strongly influenced by the technological scheme.

Currently used in industry technologies (processes Fina/Badger and Lummus/UOP Classic SM) satisfy the requirements of thermodynamics of the reaction, through the use of processes that use bulk catalysts, mainly on the basis of iron oxide and promoted with alkali, and which include the use of: - multiple adiabatic reactors connected in series, with intermediate steps of heating at a temperature in the range from 540oWith up to 630oWith and the duration of contact of the order of tenths of a second; - reactors radial-flow type, which operate under vacuum conditions at a pressure in the range from a 30.39 to 50,65 kPa (absolute Pascal) (from 0.3 to 0.5 ATA (absolute atmospheres)); and water vapor, which serves together with subjected to dehydrogenation feedstock.

Water is the main component fed to the reactor materials. Usually its molar concentration is 90%, although often establish and higher concentrations in order to extend the service life of the catalyst.

Couples performs the following functions: - reduces the partial pressure of products is which is deposited on the catalyst surface, moreover, the regeneration of the catalyst by air is not carried out; - provides the heat required for dehydrogenation of ethylbenzene; slows down the aging of the catalyst.

Following these technologies achieve the degree of conversion in the range from 60 to 65%, with a selectivity to styrene is above 90 wt.%.

However, these methods have the following disadvantages: the use of large quantities of steam (the ratio of moles H2O/EB=9,0-10), superheated to temperatures above 700oWith, requires the use of furnaces with overheating and, therefore, the high capital costs; - aging of the catalyst and, hence, the need to replace it after 18-36 months, due to the stop of the installation, and thus interrupts the production time required for replacement of the catalyst;
- sub-optimal utilization of energy; in fact, modern technology include only the utilization of explicit vapour heat, but not the latent heat;
- carrying out the reaction under vacuum (average absolute pressure 40,52 abs. kPa (0.4 ATA)), and therefore, in extremely dilute phase EB; the partial pressure of EB on average equal 4,052 abs. kPa (0,04 ATA).

Now found that these disadvantages can be overcome by the way in Colorada iron, printed on microspherical alumina-modified silica, and metal oxides as promoters.

The proposed method has significant economic advantages, in particular:
- the temperature profile of the reactor is favorable for thermodynamics of the reaction;
- heat is directly supplied to the reaction with the regenerated catalyst, so heat is not needed furnace from overheating, and a strong mixing of the fluidized bed prevents the formation of hot zones, which lowered the selectivity;
- has the ability to regenerate hydrogen;
- the plant can be operated more flexibly from the point of view of actual performance against projected;
- reaction dehydrogenation and regeneration occur in physically separated areas; this prevents mixing of hydrocarbon streams with streams of oxygen;
the process is carried out at atmospheric or slightly elevated pressures; as a result, in the reaction zone does not penetrate the air from the environment;
- molar concentration of the inert gas with respect to ethylbenzene in the feed raw materials is much lower compared to industrial technology;
- there is no need the build process without water vapor, there is no chemical poisoning of the catalyst.

In Japanese patent application 7-328439 described method of dehydrogenation of ethylbenzene in the presence of a catalyst which consists of aluminum oxide, which caused a complex of potassium ferrate and possibly oxides of rare earth elements, modified by the addition of oxides of base metals. The specified catalyst active in the presence of water, but in the referenced patent application no data about the characteristics of the catalyst in the absence of water supplied together with ethylbenzene, no details about the aging of the catalyst. Unexpectedly, it was found that partial modification of the medium aluminum oxide-silicon dioxide can significantly improve the performance of the catalyst relative to the yield in the reaction of dehydrogenation with obvious advantages. At the same time, the mechanical stability of the catalyst when the modification of the silica is increased, which makes the catalyst more suitable for operation in a reactor with a fluidized bed. Moreover, the catalyst can also function in the presence of nitrogen, and not just water.

Accordingly, the invention relates to a method for dehydrogenation e the tion, in the reactor with a fluidized bed in the presence of a catalytic system consisting of iron oxide and promoters deposited on alumina, modified from 0.01 to 10 wt.% silicon dioxide, at a temperature in the range from 400 to 700oWith a total pressure from 10,13 until the volume reached 303.9 abs. kPa (0.1 to 3 ATA) and the time rate of gas supply in the range of from 50 to 10000 h-1(normal liters of a mixture of ethylbenzene and inert gas/h x liter of catalyst); and
(b) regeneration of the catalyst in the regenerator by burning coke deposited on its surface at a temperature above 400oC.

The catalytic system used in the proposed method, consists of:
(1) 1-60 wt.%, preferably 1-20%, iron oxide;
(2) 0.1 to 20% wt.% preferably 0.5 to 10%, of at least one oxide of an alkaline or alkaline-earth metal;
(3) 0-15 wt.%, preferably 0.1 to 7%, the second promoter comprising at least one oxide of rare earth element;
(4) the complement to 100% of a carrier comprising microspherical alumina with a diameter selected from the diameters of the particles Delta, theta phase, or mixtures thereof, theta + alpha phase, or Delta + theta + alpha phase, modified, preferably 0.08 to 5 wt.% silicon dioxide.

to bring to the group And in accordance with the classification of Geldart (Gas Fluidization Technology, D. Geldart, John Wiley & Sons), and its surface area is less than 150 m2/g (BET).

Alkaline metal, preferably used in this invention as the first promoter is potassium. Preferred second promoters belonging to rare earth metals are cerium, lanthanum and praseodymium.

For example, the proposed catalyst consists of:
(1) 5-50 wt.% iron oxide;
(2) 0.5 to 10 wt.% promoter, presented in the form of oxide;
(3) the complement to 100%, representing the media, consisting of microspherical alumina with particle diameters in the range from 50 to 70 microns, selected from aluminum oxide in the form of Delta, theta phase, or mixtures thereof, theta + alpha phase, or Delta + theta + alpha phase, modified, preferably 0.08 to 3 wt.% silicon dioxide.

The above method of obtaining a catalytic system essentially can be accomplished through the following stages:
- obtaining solutions based on derivatives of compounds of the components of the catalytic system;
- application solutions for carriers, as defined above;
- drying the obtained solid substance;
- the calcination of the dried solids at a temperature in the range from 500 to 900oC.

Diperkirakan, ion exchange, vapor deposition, or surface adsorption.

It is preferable to use the method of impregnation "initial wetting".

In accordance with a preferred embodiment of the invention the catalyst was prepared as follows:
(a) add an aliquot of the promoters to the media;
(b) dried at 100-150oWith and possibly calcined dried solid substance at a temperature not exceeding 900o;
(C) causing the iron oxide and the remaining aliquot of promoters on the modified media (a);
(g) dried at 100-150oWith dried and calcined solid material at a temperature in the range from 500 to 900oC.

Operations (C) and (d) can be repeated several times.

Nitrogen, methane, hydrogen or water vapor can be used as inert gaseous substance at a volume ratio of inert gas/ethylbenzene in the range of from 1 to 6, preferably from 2 to 4. Preferably the use of methane and nitrogen.

In accordance with the following variant of the proposed method ethylbenzene can be fed to the reactor simultaneously with paraffin selected from ethane, propane, isobutane, to conduct simultaneous dehydrogenation together POI, if ethylbenzene is served with ethane, the method can be carried out, as described in U.S. patent 6031143.

In accordance with the following variant of the proposed method, the ethylene can be retalitate in the alkylation plant together with a stream of benzene to produce ethylbenzene.

The catalyst in the system of the reactor-regenerator, continuously circulates fluid between the reactor and regenerator, which allows to carry out the process in a continuous mode.

The heat required for the reaction, provides the regenerated catalyst enters the reactor at a higher temperature than the average temperature of the reaction.

The catalyst is kept in the fluidized state in the reactor using a mixture of reagents (inert gas/ethylbenzene), which flows into the catalyst bed from the bottom using a suitable distribution system.

The reacted gas after passing through the cyclone system or other pilotless system leaves the reactor through the upper part. This gas can then be directed into the heat exchanger for pre-heating fed to the reactor raw material, and then in section separation, where the obtained styrene allocate, neprerihvnogo) was isolated and used in the regenerator as a gaseous fuel.

The catalyst moves in a fluidized state in the reactor countercurrent with respect to the gas phase. He enters the catalyst bed above the distributor, which evenly disperses on the surface layer, and leaves the reactor from the bottom, passing under the action of gravity in the desorption zone, where the displacement and desorption of gas inside the particles, and nitrogen or methane injected from the bottom, so moved or desorbed gas is again supplied to the reactor, and thus prevent loss of reactants or products.

It is preferable to operate the reactor with a fluidized bed as follows:
- at a temperature in the range of from 450 to 650oWith depending on the reaction that you want to spend; the temperature is maintained within predetermined limits by adjusting the flow rate of regenerated catalyst;
- at atmospheric or slightly elevated pressures;
- when the time rate of gas supply in the range between 100 and 1000 h-1preferably from 150 to 300 h-1;
when the residence time of the catalyst in the fluidized bed in the range from 5 to 30 minutes, and in the area of desorption from 0.2 to 10 minutes.

In accordance with the embodiment pregledi, having a free area in the range from 10 to 90%, preferably from 20 to 40%. The purpose of the grids is to prevent re-mixing of the gas and catalyst, so that the gas flow inside the reactor resembled the flow of ideal displacement. The use of these gratings allows to increase the conversion of ethylbenzene and selectivity to styrene.

The reaction selectivity can be improved longitudinal temperature profile, which is installed along the catalyst layer, with the maximum temperature in the upper part, where does the regenerated catalyst, and with minimum temperatures in the lower part. The temperature difference along the layer preferably is in the range from 15 to 65oC.

For optimization of the longitudinal temperature profile of the regenerated catalyst can be distributed at different altitudes catalytic layer.

Fluidized catalyst is then sent to the regenerator by means of a pneumatic transportation system, consisting of:
a - line transportation, having at least one zone in which the catalyst moves downward through the introduction of appropriate amounts of gas at the appropriate heights, and
area, hectares at the base of the lift.

Preferably, the dimensions of the regenerator were close to the size of the reactor to maintain the catalyst at a time which is sufficient for regeneration.

Regeneration of the catalyst is carried out by combustion of coke with air and oxygen, while its heat is produced using methane, a flammable gas or by-products of the dehydrogenation reaction at a temperature higher than the average reaction temperature.

The movement of solid particles and gas is countercurrent in the regenerator: air enters the lower part of the catalytic layer, whereas the combustible gas is injected at a suitable height along the layer.

The gas leaving the regenerator and consisting essentially of nitrogen and combustion products are passed through a cyclone system or another system, placed in the upper part of the apparatus to separate the trapped fine material, and then sent to a heat exchanger for preheating combustion air.

Before release to the atmosphere, these gases can pass through a filter system or other devices to reduce the content of suspended substances to a few tenths of a milligram per normal m3gas.

Preferably, from 100 to 1000 h-1and when the residence time of catalyst in the range from 5 to 60 minutes, preferably from 20 to 40 minutes.

The regenerated and heated catalyst is directed into the reactor by means of a pneumatic system having the above characteristics.

Using the system of the reactor and the regenerator has the following advantages:
- ability to maintain constant operating parameters and characteristics of the catalyst during the whole lifetime of the installation;
- heat is transferred to the reaction directly regenerated catalyst; therefore, there is no need in furnaces, superheaters for heat transfer and intensive mixing of the fluidized bed prevents hot spots, which lowered the selectivity;
- hydrogen can be retalitate;
- the process can be done continuously, while not changing the operating parameters during the lifetime of the installation;
- reaction and regeneration occur in physically separated areas, so that the hydrocarbon streams are not mixed with oxygen-containing streams;
- molar concentration of the inert substance ethylbenzene in the downloadable raw materials is much lower compared to industrial technology.

In Fig.1 predstalena, supported on a carrier.

Liquid flow ethylbenzene (1), consisting of fresh and recycled raw material which at room temperature and pressure 263,38 abs. kPa (2,6 ATA), is evaporated in the evaporator (2), pre-heated to approximately 420oWith the gas-gas heat exchanger (3) are mixed in a suitable mixer (4) flow (5), mainly consisting of nitrogen, the origin of this flow is described below, and fed into the reactor (6) using a suitable dispenser, located in the lower part. Stream (7) arising out of the reactor at a temperature of 600oAnd pressure 135,74 abs. kPa (1,34 ATA), essentially consisting of nitrogen, styrene, hydrogen and unreacted ethylbenzene are first cooled in a gas-gas heat exchanger (3) and the second cooling in a gas-gas heat exchanger (8), from which the stream flows at a temperature of 320oC. This stream then passes through a filtering system (9) to remove the trapped fine particles, and then it is cooled with water to a temperature of 40oWith the heat exchanger (10). The mixture at this temperature becomes mushy in the partial condensation of the hydrocarbon.

The condensed stream (12) is recovered from the lower part of the phase RA is defined in detail, where using techniques known to experts in this field, there are the following threads:
- the flow (15), consisting of pure styrene (product);
- the flow (16), consisting of ethylbenzene, which recycle to the dehydrogenation;
thread (17), essentially consisting of nitrogen and hydrogen containing light hydrocarbons;
thread (18), essentially consisting of benzene and toluene;
thread (19), consisting of by-products, representing heavy hydrocarbons.

Stream (17), after the release thread (20), is heated in a gas-gas heat exchanger (21) to a temperature of 550oWith and served in the regenerator (22) by means of the distributor (23), which is located above the inlet for the air. The air stream (24) is compressed in the compressor (25) and pre-heated to a temperature of 560oWith the gas-gas heat exchanger (26) before entering the regenerator (22). Flowing from the regenerator stream (27), consisting mainly of nitrogen and water vapor is then cooled in heat exchanger (21) and (26), pass it through a filter (28) to remove trapped fine powders and cooled in the heat exchanger (29) at 40oC.

The flow of condensed water (30) is separated in the vessel (31), while the remaining gas is 263,38 abs. kPa (2,6 ATA), and then cooled in the heat exchanger (34) at this temperature, so that the almost complete condensation of water present. The condensed stream (35) is removed from the bottom of the vessel (36), while the gas flow (37), after part of it is dated (38), is heated in a gas-gas heat exchanger (8). The resulting stream (5) is then treated as described above.

All inspections of the catalyst is carried out by using a quartz micro-reactor, which put 50-100 ml of catalyst. The reactor is heated using an electric furnace to maintain the catalyst bed at the desired temperature.

Ethylbenzene fed into the evaporator by means of the metering pump, and then mixed with the inert gas, the flow rate of which is measured by a rotameter.

The reaction mixture is heated to 200oWith and fed into the reactor from the bottom through a calibrated membrane, which acts as a gas distributor, which causes fluidization of the catalyst.

At the head of the reactor has an expanding quartz vessel, the function of which is to slow the speed of the outgoing gas and make small catalyst particles to fall back into the reactor. Line extended ethylbenzene and any possible serious side products.

The catalytic cycle consists of:
- stage reaction, in which ethylbenzene, mixed with an inert substance or paraffin, is fed into the reactor for 10 minutes;
- stage desorption, in which nitrogen is passed for about 15 minutes to remove the products adsorbed on the catalyst;
- stage regeneration, which served in the air for about 45 minutes; and
- stage flushing with nitrogen for about 20 minutes.

The catalytic cycle is conducted continuously for 100 hours, with no loss in catalyst activity.

The dehydrogenation reaction is carried out at 560-650oWith, while the regeneration is carried out at 660oC.

The value of the total flow rate, expressed in litres of ethylbenzene under normal conditions plus liters of inert substances under normal conditions, the support is equal to 3005 standards. l/h/l catalyst layer.

During the stages of the reaction and desorption output stream is cooled in a trap immersed in liquid nitrogen, in which condense unreacted ethylbenzene, styrene and condensable by-products. The exit stream from a trap is sent to the bag from which extract hydrogen, inert substances is the Ktsia weighed and analyzed by gas chromatography using a gas chromatograph HP 5890, equipped with a capillary column CF WAX 10. Dosing components perform when using an internal standard.

The gas discharged from the bag, analyze gas chromatography using the procedures of external standard for measuring components. The contents of the bag is determined by the meter for the compilation of the material balance.

Incorporated on the surface of the catalyst, the coke is burned with air, and the output stream is collected in the bag. The gas is then analyzed gas chromatography to determine the concentration of CO2and its volume is measured to establish the amount of coke formed during the reaction.

The following examples, whose sole purpose is a more detailed description of the present invention in any way should not be construed as limiting the scope of invention.

Example 1.

Received resulting pseudoboehmite with particle diameters in the range from 5 to 300 μm, to which was added silica (1.2 wt%), using a spray drying the Sol of hydrated aluminum oxide and colloidal silicon dioxide "ludox" (Ludox).

Sample pseudoboehmite was progulivali at 450oC for 1 hour, and why 1190oIn .gif">andphases of aluminum has a specific surface 34 m2/g and the porosity is 0.22 cm3/,

150 g microspherical alumina was impregnated, using the technique of "initial wetting", 33 ml of an aqueous solution containing 7,8 g KPO3(level of 99.5%) in deionized water, maintaining a temperature of 25oC.

The impregnated product was dried at 80oC for 1 hour, and then progulivali at 650oC for 4 hours in a stream of dry air. The concentration of potassium oxide was 2.4 wt.% with respect to the calcined product.

Then was prepared by impregnating solution dissolved in 23 ml of deionized water of 56.2 g of Fe(NO3)3N2On (titer 99 wt.%) and 6.7 g KPO3(the title of 99.5 wt.%). The solution is heated to 50oFor complete dissolution of the salts, maintained at this temperature during the whole time of soaking.

Aluminum oxide modified with potassium oxide (153,6 g) was soaked with aliquot (48 g) impregnating solution, dried at 120oC for 4 hours and again soaked the remaining aliquot impregnating solution.

The impregnated product was dried at 120oWith during the night and, finally, progulivali at 700oEitel - the rest is up to 100%.

The resulting product was tested in the reaction of dehydrogenation of ethylbenzene to styrene, and table. 1 shows the average results obtained after 100-hour trial experience.

Example 2.

150 g microspherical alumina, obtained as described in example 1 was impregnated with a solution containing 56,3 g Fe(NO3)3N2On (titer 99 wt.%) and 14.2 g KPO3(the title of 99.5 wt.%).

The impregnation, drying and calcination was performed according to the same procedure described in example 1.

The mass composition of the obtained product are the following: 6,6% Fe2About3, 4% K2O and the media - the rest is up to 100%.

The average results for the dehydrogenation of ethylbenzene obtained after 100-hour trial experience, are given in table. 1.

Example 3.

Used the same technique as in example 2, but using an impregnating solution containing: 55,2 g Fe(NO3)3N2On (titer 99 wt.%) and 6.7 g KNO3(the title of 99.5 wt.%).

The mass composition of the obtained product are the following: 6,6% Fe2O3, 1.9% of K2O and the carrier - to 100%.

The average results for the dehydrogenation of ethylbenzene obtained after 100-hour trial experience, are given in table. 1.

Prime,9 g Fe(NO3)3N2O (titer 99 wt.%) and 2.8 g KPO3(the title of 99.5 wt.%).

The mass composition of the obtained product are the following: 6,5% Fe2O3, 0.8% of K2O, and the media up to 100%.

The average results for the dehydrogenation of ethylbenzene obtained after 100-hour trial experience, are given in table. 1.

Example 5.

Used the same technique as in example 2, but using an impregnating solution containing br93.1 g Fe(NO3)3N2O (titer 99 wt.%) and 14.8 g KPO3(the title of 99.5 wt. %) at a temperature of 60oC. the Impregnation was carried out in three stages, using 45 g of uterine impregnating solution at each stage.

The first aliquot was added to the same aluminum oxide, which was then dried at 120oC for 4 hours after treatment. This treatment was repeated twice.

The mass composition of the obtained product are the following: 10,3% Fe2O3, 4% K2O and the carrier - to 100%.

The average results for the dehydrogenation of ethylbenzene obtained after 100-hour trial experience, are given in table. 1.

Example 6.

A carrier with a surface area of 100 m2/g was obtained by calcination of the same pseudoboehmite containing silicon oxide>3N2O (titer 99 wt. %), 17,23 g KPO3(the title of 99.5 wt.%), 9,27 g of CE(NO3)36N2O and 2.93 g of La(NO3)36N2O at a temperature of 60oC. the Impregnation was carried out in one stage.

The impregnated material was dried at 120oC for 4 hours and then progulivali at 750oC for 4 hours.

The mass composition of the obtained product are the following: 5,0% Fe2About3, 3,68% K2O, 0.5% of CE2About3that 0.5% of La2O3and the media - the rest is up to 100%.

The results of the dehydrogenation of ethylbenzene received during the 150-hour trial experience, are given in table. 2.

Example 7 (comparative).

To demonstrate the activating influence of silicon oxide in the carrier, the sample was prepared as described in example 6 method, but on the basis of free silica carrier with a surface area of 104 m2/,

The average results for the dehydrogenation of ethylbenzene received during the 188-hour trial experience, are given in table. 2.

Example 8
Simultaneous dehydrogenation of ethylbenzene and ethane were carried out in the above microreactor at a temperature of 600oWith using cat who align:center; margin-top:2mm;">
Claims

1. The method of dehydrogenation of ethylbenzene to styrene, comprising: (a) the reaction of ethylbenzene, mixed with the inert gas, in a reactor with a fluidized bed in the presence of a catalytic system consisting of iron oxide and promoters deposited on alumina, modified from 0.01 to 10 wt.% silicon dioxide, at a temperature in the range from 400 to 700oWith, with a total pressure from 10,13 until the volume reached 303.9 kPa (abs. PA) (from 0.1 to 3 ATA) and an average hourly rate of gas supply in the range of from 50 to 10000 h-1(normal liters of a mixture of ethylbenzene and inert gas/hliter of catalyst), and (b) regeneration and heating of the catalyst in the regenerator at a temperature above 400oC.

2. The method according to p. 1, in which the catalyst consists of: (1) 1-60 wt.% iron oxide; (2) 0.1 to 20 wt.% at least one oxide of an alkaline or alkaline-earth metal; (3) 0-15 wt.% the second promoter comprising at least one oxide of rare earth metal; (4) the complement to 100%, which is a carrier consisting of microspherical alumina selected from aluminum oxide in the form of Delta, theta phase, or mixtures thereof, theta (+ alpha phase, or Delta (+ theta (+ alpha phase), modi is iron; (2) 0.5 to 10 wt.% metal-promoter, presented in the form of oxide; (3) the complement to 100%, which is a carrier consisting of microspherical alumina with a diameter in the range from 50 to 70 μm selected from aluminum oxide in the form of Delta, theta phase, or mixtures thereof, theta + alpha phase, or Delta (+ theta (+ alpha phase, modified, preferably 0.08 to 3 wt.% silicon dioxide.

4. The method according to any of paragraphs.1-3, in which a promoter selected from alkali, alkaline-earth metals or lanthanides group.

5. The method according to p. 4, in which the promoter is an oxide of potassium.

6. The method according to p. 4, in which the promoters are potassium oxide, cerium oxide, lanthanum oxide and praseodymium oxide.

7. The method according to any of paragraphs.1-6, in which the catalyst is obtained by: (a) adding an aliquot of the promoter to the media; (b) drying at 100-150oWith and possibly calcination of the dried solids at a temperature not exceeding 900oWith; (b) dispersion of the iron oxide and the remaining aliquots of the promoter on the carrier obtained in operation (a) and (g) drying at 100-150oC and calcination of the dried solids at a temperature in the range from 500 to 900oC, and the operation (C) and (d) can be repeat the RA.

9. The method according to p. 8, in which the inert gas is selected from nitrogen and methane.

10. The method according to p. 1, in which the volume ratio of inert gas/ ethylbenzene is in the range from 1 to 6.

11. The method according to p. 10, in which the volume ratio is in the range from 2 to 4.

12. The method according to p. 1, in which the dehydrogenation reaction on operation (a) is conducted at a temperature in the range of from 450 to 650oC, at atmospheric or slightly elevated pressure, with an hourly space velocity of gas in the range from 100 to 1000 h-1and when the residence time of catalyst in the range from 5 to 30 minutes

13. The method according to p. 12, in which the space velocity is in the range from 150 to 300 h-1, and the residence time of the catalyst is in the range from 10 to 15 minutes

14. The method according to p. 1, in which the operation (b) regeneration of the catalyst is carried out by means of air or oxygen, and the heating is carried out with the use of methane, a flammable gas or by-products of the dehydrogenation reaction, operating at a higher temperature than the average temperature of the dehydrogenation reaction, at atmospheric or slightly elevated pressure, with flow rate range from 100 to 1000 h-1and when the residence time of the catalyst is from 5 to 60 minutes

16. The method according to p. 1, in which the operation (s) in the reactor serves ethylbenzene, mixed with paraffin selected from ethane, propane or isobutane with simultaneous dehydrogenation components of a mixture from the formation, respectively, of styrene and the corresponding olefins.

17. The method according to p. 16, in which the reactor serves ethylbenzene, mixed with ethane with simultaneous dehydrogenation components of a mixture from the formation, respectively, of styrene and ethylene.

18. The method according to p. 17, in which the ethylene recycle in the installation for alkylation with the stream of benzene to form ethylbenzene.

 

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