A method of producing benzene and xylenes

 

(57) Abstract:

A method of producing benzene and xylenes. Use: petrochemical synthesis. The inventive products: benzene BF6H6, toluene BF7H8, the total yield of 24.6 - 32,9%. Raw material: propane or butane or a mixture thereof. Catalyst: zeolite ZSM - 5 modified with 0.5 to 3.0% Zn or Ga. Conditions: 400 - 600oC. Reactor unit consisting of 3 - 4 series-connected reactors. Recycling the toluene fraction in the last along the reactor. The contact time in the reactor of 0.5 - 2 C. 1 C. p. F.-ly, 2 ill., 9 table.

The invention relates to petrochemical synthesis, more specifically to the production of benzene and xylenes.

The main method for industrial production of benzene and xylenes is catalytic reforming. As the process feedstock used gasoline fraction, which is scarce raw materials, the process is conducted at 480-520aboutWith the pressure of the hydrogen 7-25 at.

Disadvantages of the process are the scarcity and high cost of raw materials, the need for recirculation of large amounts of hydrogen, the need for extractive selection of xylenes due to the presence of paraffin hydrocarbons with similar temperatures Ki is the share of thermal processing of heavy petroleum fractions. The latter are sources of hydrocarbons3-C4not having still qualified use. These hydrocarbons are associated oil gases, therefore, the most promising are the processing of hydrocarbons3-C4in aromatic hydrocarbons.

The known method of synthesis of benzene, toluene and xylenes from hydrocarbons WITH3-C4when the temperature 482-537aboutWith a minimum working pressure of 9105PA and volumetric feed rate of the raw material 2 h-1(time of contact of the hydrocarbons WITH3-C4with catalyst 5) using as the catalyst a variety of highly siliceous zeolites of type ZSM containing zinc or gallium. The process is carried out in a cascade of series-connected reactors heated reaction products between the reactor with continuous catalyst regeneration [1]

The main disadvantages of this process are the relatively low yield of benzene and xylenes due to the formation of toluene and aromatic hydrocarbons WITH9+and gaseous products, the total yield of benzene and xylenes is 26-27 wt.

The closest tehnicheskaya benzene or toluene [2] as the catalyst used is a zeolite of type ZSM-5 coated with gallium (0,1-10%). The process is carried out as follows (see Fig. 1). Propane (thread 1) together with the part highlighted in benzene or toluene to 8 mol. hydrocarbons (stream 2), and hydrogen (stream 4) are delivered to the reaction block 6 at a temperature of 487-565aboutAnd pressure of 5-7 at. The total residence time of the raw material mixture in the reaction zone 6-7 C. In the reaction of dehydrocyclization is obtained a mixture of products and unreacted propane (stream 7) which, passing through the condenser 8 and the separator 9, are separated. Light gases and H2in accordance with the balance returned to recycling (stream 4), and the liquid phase separated in a system of fractional columns according to Fig. 1. Part of the separated benzene or toluene (up to 8 mol. for hydrocarbons) returns to recycling.

The disadvantage of low yield of benzene and xylenes.

The aim of the invention is to increase the total yield of benzene and xylenes.

This goal is achieved by an improved method for obtaining aromatic hydrocarbons from hydrocarbon WITH3-C4using as catalyst Zn or Ga - containing high-silica zeolite catalyst ZSM-5 in the reactor unit consisting of sdelaetsja to recycle a fraction of the original alkanes, benzene, toluene, xylene and a fraction WITH9+-aromatics. Dedicated toluene fraction (all or part of it) is sent to recycling.

In the proposed method, the target products are benzene and xylenes. Recycling the toluene is not in the first reactor, and in the latter in order to provide the necessary residence time of 0.5-2 s, which allows to increase the yield of benzene and xylenes, which is associated with an increase in the selectivity of the process for benzene and xylenes 1.3-1.7 times. The long residence time of more than 2, leads to the reduction of the yield of benzene and xylenes, increased flatulence and increase in the proportion WITH9+-aromatics.

The proposed method can be carried out in the reactor block with a fixed catalyst bed, or moving bed of catalyst and with continuous regeneration.

The process of aromatization of hydrocarbons3-C4in the former carried out as follows (see Fig.2). In the reactor unit consisting of 3 to 4 consecutive reactors, serves a mixture of hydrocarbons WITH3-C4(thread 1) in the first as the reactor 2. Hydrocarbons WITH3-C4with the reaction products consistently come in second 3 third 4 and at a temperature of 400-600aboutAnd the total time of contact 5-7 C. the Catalyst reactors distributed in such a way (with a fixed bed of catalyst), the time of contact in the last reactor of the reactor block was varied in the range 0.5 to 2 C. In the reactor unit with a movable layer of the catalyst to the desired contact time in the last reactor with the catalyst is achieved by changing the location of the input toluene fraction.

Toluene fraction after separation (all or part of it depending on the needs of the production) is heated and served in the last reactor of the reactor block (stream 6). The reaction products and unreacted3-C4(stream 7) through the cooler-condenser 8 are received in separator 9, where the separation H2WITH1and C2.

Then the reaction products and unreacted3-C4(stream 11) are separated in the column 12 of the stabilizing liquid products. Fraction WITH3-C4taken on the top of the column at a temperature of 60aboutC, a pressure of 12 and at reflux 3. Unreacted3-C4(stream 13) return to the process, and liquid products (stream 14) is separated by rectification method in the system columns: in column 15 at a temperature 80-81aboutAnd FL is the atur 110aboutWith and reflux 3 (stream 19); in column 21 of the cubic product of the column 18 at a temperature 138-142aboutWith and reflux 5 are xylenes (stream 22), and from the cube column 20 shows the fraction of aromatic hydrocarbons WITH9+(stream 23).

The amount of recycled toluene is limited only by the contact time stream containing toluene, catalyst during the last reactor and the necessary completeness of the conversion fraction WITH3-C4in the process.

The effectiveness of the proposed method is illustrated by the following examples. For convenience compared the performance of the process is at 100% conversion of propane.

P R I m e R 1 (the prototype). In the reaction block 6 (see Fig.1) at a temperature of 560aboutC and a pressure of 5 at serves 100 kg/h of high purity propane (stream 1), this comes from the column 21 stream 2, representing the toluene in the amount of 12,55 kg/h, which corresponds to 6 mol. of toluene. The total residence time of the raw material mixture in the reaction zone 6-7 C. as the catalyst is zeolite ZSM-5 with a module 60 and deposited gallium in the amount of 3% by the reaction of dehydrocyclization receive the mixture of reaction products (stream 7), which send the balance threads the conversion of propane to aromatics is 66%

The yield of aromatics excluding re-circulating flow 66 kg/h, the yield of benzene and xylenes 23,56 kg/h or 20,93% of the raw material. The selectivity to benzene and xylenes is 23,56 wt.

P R I m m e R 2. In the reactor unit consisting of four consecutive reactors (see Fig.2) serves to 100 kg/h of propane. The process is carried out on silica zeolite ZSM-5 with silicate module 60, containing 1.5% zinc, at a temperature of 570aboutAnd bulk supply of liquid propane 2 h-1. Leaving the last reactor, the reaction products are cooled in the refrigerator 8 and fed to the separator 9, where the separated hydrogen and hydrocarbons1-C2.

Liquid products are sent to the column 12 of the stabilizing liquid products, where on top of selected hydrocarbons WITH3-C4. VAT product is sent to the column 15 allocation of benzene. CBM product columns 15 are fed to the separation column 18, where the top emit toluene, and CBM product is fed to the column 21. In column 21 on top of the produce xylenes, and Cuba get WITH9+the aromatics.

The whole toluene (stream 6), highlighted in the column 18, sent to the last reactor. The time of contact of the thread containing the existing one pass of toluene in the experience without recycling, are given in table.2. The yield of aromatics excluding re-circulating stream of toluene 58,3% yield of benzene and xylenes 41,0 kg/h (or 32.9 per cent to raw materials), which is 1.7 times higher than in the prototype, and the selectivity to benzene and xylenes 41 wt.

P R I m e R 3. The process is conducted as in example 2, but at 600aboutWith voluminous flow of hydrocarbons FROM3-C41 h-1catalyst: silica zeolite ZSM-5 c silicate module 60, containing 1.5 gallium in the reactor unit consisting of 3 reactors. The time of contact of the stream containing toluene is 2.0 C. the Toluene formed for the passage fully (100% returns in the last reactor of the reactor block.

The composition of the obtained products are shown in table.3.

The yield of benzene and xylenes was 38,0 kg/h (or 30,5%), the selectivity of the formation of benzene and xylenes 38 wt. which is 1.6 times higher than in the prototype.

P R I m e R 4. The process is conducted as in example 3, but at a temperature of 400aboutWith on silica zeolite ZSM-5 containing 0.5% gallium. In the last reactor unit serves 20 kg/h of toluene. The composition of the products is presented in table.4. The yield of benzene and xylenes was 36.6 kg/h (30,5%), the selectivity of the formation of benzene and kilolo zeolite catalyst modified with zinc in the amount of 3% and the time of contact of the thread containing toluene, 0.8 sec.

The composition of the obtained products are shown in table.5.

The yield of benzene and xylenes was 33,0 kg/h (26.5%), the selectivity of the formation of benzene and xylenes of 33.0 wt. which is 1.4 times higher than in the prototype.

P R I m e R 6. The process is carried out at 450aboutWith voluminous flow of hydrocarbons FROM3-C41.5 h-1on silica zeolite ZSM-5, containing 1.5% gallium. In recycling are sent to all of toluene, and 10 wt. i.e. 2,50 kg Time contacting a stream containing toluene, 1,0 C.

The composition of the obtained products are shown in table.6.

The yield of benzene and xylenes was 30.8 kg/h (or 24,6%), the selectivity of the formation of benzene and xylenes 30,8% which is 1.3 times higher than in the prototype.

P R I m e R 7 (for comparison). The process is carried out at 560aboutWith voluminous supply of propane 2 h-1catalyst: silica zeolite ZSM-5 containing 3.0 percent gallium. Toluene is served in the last reactor unit consisting of four reactors, where the residence time of the stream containing toluene, 0.3 sec.

The composition of the obtained products are shown in table.7. The yield of the target products of benzene and xylenes (threads 16 of 22) in this way is 39,0% (compared to 41.0%). The conversion of toluene at contact time of 0.3 s also less than in example 2, and 42% (vs. 50%). In addition, when reducing the residence time of 0.3 s for the passage falls conversion of propane and increases the load on the very energy-intensive gas separation system.

P R I m e R 8 (for comparison). The process is carried out at 560aboutWith voluminous supply of propane 1 h-1on silica zeolite ZSM=5 with silicate module 60, containing 1.0 zinc. The time of contact of the stream containing toluene, in the last reactor unit consisting of 3 reactors is 3.0 C. the Composition of the obtained products are shown in table.8. The yield of benzene and xylenes was 32.4 kg/h (26,0%), the selectivity to benzene and xylenes 32,4 wt. higher than in the prototype by 37% but less than in examples 3 and 4 by 12-17% in Addition, with increasing time of contact significantly increases the content of hydrocarbons WITH1-C2and the content of heavy aromatics, which affects the reduction of total aromatics: 48,7% against 55,1 and 54.7 in examples 2 and 3.

In table.9 presents comparative data of process indicators examples 1-8.

1. A METHOD of producing BENZENE AND XYLENES by contacting alkanes C3- C49+-aromatic hydrocarbons and a recycle toluene fraction to the stage of contact, characterized in that, to increase the total yield of benzene and xylenes, recycling the toluene fraction is sent to the last during the reactor and the process in the reactor is carried out at contact times of 0.5 - 2 C.

2. The method according to p. 1, characterized in that the process of contacting is carried out at 400 - 600oC.

 

Same patents:

The invention relates to the production of motor fuels and can be used in refining and petrochemical industries

The invention relates to the catalytic conversion of hydrocarbons and can be used to produce high octane motor fuel

The invention relates to the field of petrochemical synthesis, namely the production of aromatic hydrocarbons from the lower paraffins WITH3-C4

The invention relates to organic catalytic chemistry, in particular to the processing of hydrocarbon resins, namely phenolic resin in the fraction of aromatic hydrocarbons containing mainly benzene and isopropylbenzene (cumene), and can be used in the petrochemical and chemical industry

The invention relates to the extraction of benzene hydrocarbons from coke oven gas by absorption of light coal oil, followed by separation from the circulating oil by distillation with water vapor and can be used in purification processes from gases of hydrocarbons in coke, coke and gas and other industries

The invention relates to the catalytic conversion of hydrocarbons and can be used to produce high octane motor fuel

The invention relates to the field of petrochemical synthesis, namely the production of aromatic hydrocarbons from the lower paraffins WITH3-C4

The invention relates to the production of aromatic hydrocarbons

FIELD: petrochemical processes.

SUBSTANCE: simultaneous dehydrogenation of mixture containing alkyl and alkylaromatic hydrocarbons is followed by separating thus obtained dehydrogenated alkyl hydrocarbon and recycling it to alkylation unit. Dehydrogenation reactor-regenerator employs C2-C5-alkyl hydrocarbon as catalyst-transportation carrying medium.

EFFECT: increased process flexibility and extended choice of catalysts.

36 cl

FIELD: organic synthesis catalysts.

SUBSTANCE: invention relates to catalyst for aromatization of alkanes, to a method of preparation thereof, and to aromatization of alkanes having from two to six carbon atoms in the molecule. Hydrocarbon aromatization method consists in that (a) C2-C6-alkane is brought into contact with at least one catalyst containing platinum supported by aluminum/silicon/germanium zeolite; and (b) aromatization product is isolated. Synthesis of above catalyst comprises following steps: (a) providing aluminum/silicon/germanium zeolite; (b) depositing platinum onto zeolite; (c) calcining zeolite. Hydrocarbon aromatization catalyst contains microporous aluminum/silicon/germanium zeolite and platinum deposited thereon. Invention further describes a method for preliminary treatment of hydrocarbon aromatization catalyst comprising following steps: (a) providing aluminum/silicon/germanium zeolite whereon platinum is deposited; (b) treating zeolite with hydrogen; (c) treating zeolite with sulfur compound; and (d) retreating zeolite with hydrogen.

EFFECT: increased and stabilized catalyst activity.

26 cl, 1 dwg, 5 tbl, 4 cl

FIELD: CHEMISTRY.

SUBSTANCE: zeolite catalyst for process of conversion of straight-run gasoline to high-octane number component is described. The said catalyst contains high-silica zeolite with SiO2/Al2O3=60 and residual content of Na2О of 0.02 wt.% maximum, metal-modified, Pt, Ni, Zn or Fe metals being in nanopowder form. Content of the said metals in the catalyst is 1.5 wt.% maximum. Method to manufacture zeolite catalyst for conversion of straight-run gasoline to high-octane number component is described. The said method implies metal modification of zeolite, Pt, Ni, Zn or Fe metals being added to zeolite as nanopowders, produced by electric explosion of metal wire in argon, by dry pebble mixing in air at room temperature. Method to convert straight-run gasoline using the said catalyst is also described.

EFFECT: increase in catalyst activity and gasoline octane number, accompanied by increase in yield.

4 cl, 3 tbl, 4 ex

FIELD: chemistry.

SUBSTANCE: method involves hydrocarbon transformation in a reactor in the presence of modified catalyst containing, mass %: 53.0-60.0 of ZSM-5 high-silica zeolite with the ratio of SiO2/Al2O3=39, 34.0-38.0 of Al2O3, 2.0-5.0 of B2O3, 1.0-5.0 of Zn, 0.0-5.0 of W, 0.0-3.0 of La, 0.0-3.0 of Ti at 300÷700°C, including separation of liquid and solid transformation products, followed by burning oxidation of gaseous products and addition of the obtained mix of carbon dioxide and water vapour to the source hydrocarbons at the rate of 2.0÷20.0 mass %. Before the raw material intake the reaction system is flushed by an inert gas (nitrogen), starting from 300°C and to the transformation temperature. Hydrocarbons used are alkanes, olefins or alkane olefin mixes C2-C15 without preliminary separation into fractions. Gaseous transformation products undergo burning and complete oxidation in the presence of an oxidation catalyst of vanadium/molybdenum contact piece, V2O5/MoO3. To sustain continuous process two identical reactors are used, where the catalyst is transformed and recovered in turns.

EFFECT: longer working transformation cycle due to the continuous process scheme; higher yearly output of aromatic hydrocarbons; reduced energy capacity and improved ecology of the process.

2 ex

FIELD: chemistry.

SUBSTANCE: invention describes zeolite-containing catalyst for transformation of aliphatic hydrocarbons C2-C12 to a mix of aromatic hydrocarbons or high-octane gasoline component containing zeolite ZSM-5 with silicate module SiO2/Al2O3=60-80 mol/mol and 0.02-0.05 wt % of residual sodium oxide content, zeolite structural element, promoter and binding component, with zirconium or zirconium and nickel oxides as zeolite structural component, and zinc oxide as promoter, at the following component ratio (wt %): zeolite 65.00-80.00; ZrO2 1.59-4.00; NiO 0-1.00; ZnO 0-5.00; Na2O 0.02-0.05, the rest being binding component. Also, a method for obtaining zeolite-containing catalyst is described, which involves mixing reagents, hydrothermal synthesis, flushing, drying and calcinations of sediment. The reaction mix of water solutions of aluminum, zirconium and nickel salts, sodium hydroxide, silicagel and/or aqueous silicate acid, inoculating zeolite crystals with ZSM-5 structure in Na or H-form, and structure-former, such as n-butanol, is placed in an autoclave, where hydrothermal synthesis is performed at 160-190°C for 10-20 hours with continuous stirring; the hydrothermal synthesis over, Na-form pulp of the zeolite is filtered; the obtained sediment is flushed with domestic water and transferred to salt ion exchange by processing by water ammonium chloride solution with heating and stirring of the pulp; the pulp obtained from salt ion exchange is filtered and flushed with demineralised water with residual sodium oxide content of 0.02-0.05 wt % on the basis of dried and calcinated product; flushed sediment of ammonium zeolite form proceeds to zinc promoter introduction and preparation of catalyst mass by mixing of ammonium zeolite form modified by zinc and active aluminum hydroxide; obtained catalyst mass is extruded and granulated; the granules are dried at 100-110°C and calcinated at 550-650°C; calcinated granules of zeolite-containing catalyst are sorted, ready fraction of zeolite-containing catalyst is separated, while the granule fraction under 2.5 mm is milled into homogenous powder and returned to the stage of catalyst mass preparation. The invention also describes method of transformation of aliphatic hydrocarbons to high-octane gasoline component or a mix of aromatic hydrocarbons (variants), involving heating and passing raw material (gasoline oil fraction direct sublimation vapours or gas mix of saturated C2-C4 hydrocarbons) through stationary layer of the aforesaid catalyst.

EFFECT: reduced number of components and synthesis stages of zeolite-containing catalyst; increased transformation degree of raw material; improved quality and yield of target products with the said catalyst.

4 cl, 8 tbl, 12 ex

FIELD: chemistry.

SUBSTANCE: alkylbenzol with structure R1R2CH(Ph) is obtained from alkylphenyl alcohol with structure R1R2C(Ph)OH. Method includes following stages: (a) supply of initial flow, containing alkylphenyl alcohol with structure R1R2C(Ph)OH, into reactor with catalytic distillation zone; (b) simultaneously in reactor: (i) contacting of initial flow, containing R1R2C(Ph)OH, with hydrogen in catalytic distillation zone in order to convert R1R2C(Ph)OH into R1R2CH(Ph) and to form reaction mixture and (ii) separation of R1R2CH(Ph) from reaction mixture by fraction distillation in order to obtain higher than catalytic distillation zone, flow, which contains R1R2CH(Ph) with lower concentration of R1R2C(Ph)OH in comparison to initial reactor flow in position higher than catalytic reaction zone; R1 and R2 each represent hydrogen or hydrocarbon group with 1-10 carbon atoms and one of R1 and R2 is not hydrogen.

EFFECT: more pure alkylbenzol with smaller amount of undesirable by-products and using smaller number of stages.

6 cl, 5 tbl, 1 dwg

FIELD: chemistry.

SUBSTANCE: invention refers to the method for preparation of aromatic hydrocarbons accompanied with simultaneous obtaining of hydrogen, methanol, motor oils and fresh water from the unstable hydrocarbon gas condensate obtained from gas condensate and oil fields including if necessary its desulphurisation, following obtaining of synthesis gas by one-stage oxidising with air oxygen, its conversion to methanol, following catalytic conversion of methanol to motor oils, separation of the water formed on all process stages, evaporation of the hydrocarbons residues including methanol and fatty hydrocarbons from the water (united and formed on all process stages), water bioremediation and mineralisation. The initial hydrocarbon gas is unstable hydrocarbon gas condensate without preliminary separation of methane and ethane from propane and butane, the said initial gas before its conversion to synthesis gas undergoes the catalytic aromatisation during heating. Then the obtained aromatic hydrocarbon and hydrogen are separated, hydrogen is at least partially used for synthesis gas obtaining in order to change the ratio H2:CO 1.8-2.3:1), and if necessary it is partially used on the stage of desulphurisation with synthesis gas obtaining from hydrocarbon gases (unreacted and formed on the aromatisation stage). The invention refers also to the device for implementation of the method described above.

EFFECT: increasing of the processing of the efficiency of unstable hydrocarbon gas condensate with enhanced obtaining of target products, to make the process more environmentally safe, to increase the quantity and quality of the obtained fresh water.

2 cl, 5 ex, 1 dwg

FIELD: chemistry.

SUBSTANCE: method of hydrocarbon aromatisation includes: a) contacting of alkane containing from 2 to 6 carbon atom in molecule with at least one catalyst consisting virtually of platinum applied to zeolite MFI which lattice consists virtually from gallium, silicon and oxygen and b) separation of aromatic products. The preparation method for platinum-gallium zeolite catalyst used for hydrocarbon aromatisation is described, it includes: preparation of gallium zeolite containing silicon and gallium; precipitation of the platinum to said zeolite; and c) zeolite calcination. In the said method the said gallium zeolite catalyst consists virtually of platinum applied to zeolite MFI which lattice consists virtually from gallium, silicon and oxygen. The platinum- gallium zeolite catalyst for hydrocarbon aromatisation containing: a) gallium-silicon zeolite and b) platinum precipitated to gallium-silicon zeolite is also described. In the said method the said platinum-gallium zeolite catalyst consists virtually of platinum applied to zeolite MFI which lattice consists virtually from gallium, silicon and oxygen.

EFFECT: enhancing of the catalyst selectivity in transforming of lower alkanes to aromatic hydrocarbons.

30 cl, 3 dwg, 4 tbl, 2 ex

FIELD: chemistry.

SUBSTANCE: invention relates to a method of producing aromatic hyhrocarbons and lower olefins, involving catalytic dehydrocyclisation of hydrocarbon material in the presence of a zinc-containing zeolite catalyst, at high temperature and pressure, separation of dehydrocyclisation products into product A - aromatic hydrocarbons C6+, and product B - mixture of non-aromatic hydrocarbons with hydrogen, subsequent hydrodealkylation of product A, obtaining commercial-grade benzol, and pyrolysis of product B, obtaining lower olefins, and characterised by that, the dehydrocyclisation material used is C2-C6 paraffins, the process is carried out at 0.9-1.3 MPa pressure, after separating the C10+ fraction, product A is subjected to hydrodealkylation, commercial-grade benzol, methane and ethane fractions, ethane fraction and product B are separated from hydrodealkylation products, or after separating over 50 vol % methane-hydrogen fraction from product B, product B is taken for pyrolysis, commercial-grade ethylene and propylene are separated from gaseous products of pyrolysis, liquid products of pyrolysis - pyrolysis condensate, containing aromatic hydrocarbons, is subjected to catalytic hydrogenation and hydrodesulphurisation, and subsequent hydrodealkylation, obtaining commercial-grade benzol, methane and ethane fractions, the latter is returned for pyrolysis.

EFFECT: increased output of lower olefins, significant improvement of economic parametres of the process due to increase of inter-regeneration period of dehydrocyclisation catalyst.

1 cl, 5 ex, 5 tbl

Up!