The method of obtaining isoalkanes and their mixtures of normal alkanes

 

(57) Abstract:

Usage: petrochemistry. N-alkanes are served in the area of catalytic dehydrogenation, contact the gas dehydrogenation zone in an area of catalytic isomerization of n-alkenes in isoalkane in the presence of hydrogen and a contact gas isomerization zone in the separation zone. In the isomerization zone is used, the catalyst is aluminum oxide coated with silicon compounds, and/or halides, and/or a variable valence metal, preferably palladium, and isolated from the gas contact zone isomerization mixture containing mainly hydrocarbons with a carbon number of atoms, similar to the source(s) n-alkane(s), share or by chemical binding of tert-alkene(s) in the presence of an acidic catalyst with water and/or alcohol(s), and/or formaldehyde, and/or dimerization, followed by the separation of a mixture of unreacted hydrocarbons, retrieved from the n-alkenes by distillation with a polar(s) agent(s) and/or chemical binding of water and/or alcohol(s), and/or dimerization and n-alkanes returned to the dehydrogenation zone and possible n-alkenes in the isomerization zone or separated by distillation with a polar(s) agent(am tert-alkenes by chemical binding in the presence of an acidic catalyst with water, and/or alcohol(s), and/or formaldehyde, and/or dimerization and you can stream containing predominantly n-alkenes, returned to the isomerization zone. Effect: simplified process. 5 C.p. f-crystals, 3 tab., 3 Il.

The invention relates to the production of compounds isoalkanes. More specifically, the invention relates to the production of alkanes normal structure of compounds isoalkanes, such as tert-alcohols, alkyl-tert-alkalemia alcohols, dimethyldioxirane, methylbutanol, dimers tert-alkenes.

Known methods [A. N. Bushin and other Synthetic rubber.- L.: Chemistry, 1976, S. 652-663; A. N. Chaplin and others, ibid., S. 724-731] get isoalkanes and n-alkenes by dehydration, respectively, of isoalkanes and n-alkanes. Their disadvantage is the limited natural sources of isoalkanes.

There are also known methods [P. A. Kirpichnikov and other Album of technological schemes of the main industries of the UK.- L.: Chemistry, 1986, S. 53-58] get isoalkanes of normal alkanes by skeletal isomerization of n-alkanes to isoalkanes with subsequent dehydrogenation of isoalkanes. The disadvantage of this method is the complexity of the skeletal isomerization of n-alkanes, particularly n-butane (in particular, high pressure - 15-30 ATA) and the temperature (isomerization 150-250oC, the dehydrogenation ~ 600oC), and between them is necessary to carry out the cooling and condensation of the reaction mass, multicolumn distillation separation, and then re-evaporation and heating of isoalkanes and n-alkanes.

Also known way [U.S. patent N 906360, BI N 6, 1982] obtain isoalkanes by skeletal isomerization of n-alkenes in the presence of an acidic heterogeneous catalyst at a temperature of 300-600oWith, preferably 400-550oWith, with the possible use as raw material n-alkenovich fractions (including n-alkenovich fractions of C4-C5) emitted from the products of thermal processing of petroleum hydrocarbons (including products from dehydrogenation of n-alkanes).

The disadvantage of this method is that it requires submission to the isomerization zone for individual n-alkenes or mixtures of n-alkenes. The method is not intended for use as raw material of n-alkanes, and specified in the patent does not mention the possibility of filing in the isomerization zone a hydrogen-containing gas stream from the dehydrogenation of alkanes. If you simply combine the isomerization of n-alkanes with a method of obtaining n-alkenes based on the dehydrogenation of n-alkanes, in General, receipt of which shall be the allotment area of mixtures of hydrocarbons from gas contact dehydrogenation and the area of separation of n-alkenes mentioned mixtures of hydrocarbons. The patent does not provide for methods of separation of the products of isomerization and the possibility of recirculation of n-alkenes in the isomerization zone.

Known and closest to the proposed method in WO 93/03116, 18.02.93. According to the method of the claimed process mixtures containing alkanes normal structure comprising successive high-temperature zone of the gas-phase catalytic dehydrogenation of alkanes, high-temperature gas-phase catalytic isomerization of n-alkenes (after reducing the content of n-alkenes in the products and possible area(s) of separating mixtures obtained in said isomerization zone. Moreover, in the dehydrogenation zone use non-acidic catalyst containing a dehydrating metal and non-acidic macroporous crystalline material containing modifier selected from indium, thallium, lead, tin, and iridium, and the isomerization zone using a catalyst containing a zeolite selected from ZSM-5, ZSM-22, ZSM-23, ZSM-35 and ZSM-48, and impurities. Alternatively stated getting isobutene and isolation of oligomers alkenes.

The disadvantage of this method is the use in the isomerization zone catalyst zeolite (molecular sieve) patterns. For known realresults driving narrow vnutrikletochnykh passages deposits of high-molecular compounds and coke, which leads to the necessity of their high temperature regeneration (by burning sediments). Multiple high-temperature regeneration (burning) lead to the disruption of the structure of zeolites.

The disadvantage is the lack of information on the method of processing flow obtained in the isomerization zone (except for the statements that get isobutene, and that produce oligomers alkenes), and the lack of use of recycle streams alkanes and possible n-alkenes in zone dehydrogenation and isomerization.

We propose a method of obtaining compounds isoalkanes from n-alkanes by feeding n-alkanes in the area of catalytic dehydrogenation, gas contact zone dehydrogenation zone catalytic isomerization of n-alkenes in isoalkane in the presence of hydrogen and a gas contact zone isomerization in the separation zone, under which the isomerization zone is used, the catalyst is aluminum oxide coated with silicon compounds and/or halides, and/or a variable valence metal, preferably palladium, and isolated from the gas contact zone isomerization mixture containing mainly hydrocarbons with the number of carbon atoms, similar to ilitator with water and/or alcohol(s), and/or formaldehyde, and/or dimerization, followed by the separation of a mixture of unreacted hydrocarbons, retrieved from the n-alkenes by distillation with a polar(s) agent(s) and/or chemical binding of water and/or alcohol(s), and/or dimerization and n-alkanes returned to the dehydrogenation zone and possible n-alkenes in the isomerization zone, or is separated by distillation with a polar(s) agent(s) and allocated(e) alkane(s) returned to the dehydrogenation zone, from Taganai from polar agent mixture is extracted tert-alkenes by chemical binding in the presence of an acidic catalyst with water and/or alcohol(s), and/or formaldehyde, and/or dimerization and you can stream containing mainly n-alkanes, returned to the isomerization zone.

As a variant of the proposed method, according to which contact the gas supplied from the dehydrogenation zone to the isomerization zone, is cooled to a temperature less than 500oC, preferably to a temperature of 350-450oC.

As a variant of the proposed method, according to which the isomerization zone introduce additional(s) stream(s) containing(e) n-alkenes and/or water.

As a variant of the proposed method, according to which as the source of n-al is the use of the original mixture of n-butane and n-pentane from the selected contact of the gas mixture are rectification stream, containing mainly hydrocarbons, C4and a stream containing predominantly hydrocarbons, C5and carry out the separation of each of these flows.

As a variant of the proposed method, according to which the dehydrogenation of n-alkanes(s) is carried out in a stationary or fluidized bed alimohammadi and/or platypodinae catalyst.

The chemical binding of tert-alkenes get a tert-alcohol(s) and/or tert-alkyl alkilany(e) ether(s), and/or dimethyldioxirane, and/or 3-methylbutanol-1,3, and/or dimers tert-alkenes.

As raw materials can be used n-alkanes, mixtures of n-alkanes, and mixtures of n-alkanes with isoalkane and/or alkenes. In the stream fed to the dehydrogenation zone, the content of isoalkanes and isoalkanes should not exceed the amount resulting in the dehydrogenation to education to the formation of mixtures with a ratio of n - and isoalkanes close to equilibrium in terms of the subsequent isomerization, and the content of n - and/or isoalkanes should not exceed the number of harmful effects on the operation of the catalyst by the formation of excessive amounts of coke and so on).

As catalysts in the area of preferential digitraveler catalysts, containing oxides of aluminum and chromium, platinum media, etc.

In the reaction zone dehydrogenation can be any suitable for the dehydrogenation reactors and reaction nodes, equipped with systems of heat supply and/or burning of coke and other organic deposits on the catalyst and/or additional combustion of hydrocarbons, such as fuel gas, to heat the catalyst. The catalyst can be maintained in a stationary or fluidized bed ("boiling"). The dehydrogenation may be carried out continuously or cyclically, and regeneration of the catalyst directly into the dehydrogenation reactor and/or United with him(and) the system(s) catalyst regeneration. The dehydrogenation may be carried out at atmospheric, moderately elevated pressure or under vacuum.

As isomerization catalysts can be any suitable for the skeletal isomerization of n-alkenes catalysts containing alumina coated with compounds of silicon and/or halides, and/or metals of variable valence. In the area of catalytic isomerization can be made carbon tetrachloride and/or other alkylhalides.

In cuteslout(s) of the catalyst.

To retrieve isoalkanes from hydrocarbon mixtures can be used in different ways based on the chemical compound isoalkanes with water, alcohols, acids, formaldehyde in the presence of an acidic catalyst with the formation of tert-alcohols, alkyl-tert-alilovic ethers, esters, dimethyldioxanes and methyl-butanediol (with the possible subsequent receipt of isoalkanes formed by the decomposition of alcohols, ethers and esters) or ways of dimerization and trimerization isoalkanes. Thus the expression "getting connection isoalkanes" is not necessarily understood as obtaining compounds isoalkanes in concentrated form. These compounds may be in the form of mixtures, for example with water or hydrocarbons, suitable for further use and reference compounds isoalkanes, for example, to turn them into isoalkane, isoprene, etc.

For separation of alkanes from alkenes can be used a method of extractive distillation with a polar agents, acetonitrile, dimethylformamide, dimethylacetamide and others.

The invention is illustrated in the drawings and examples. These drawings and examples do not exhaust all the possible options for the implementation of the method, and

According Fig. 1, a mixture of F containing predominantly n-alkane(s) served by the line 1 in the dehydrogenation zone P-1 P-1 line 9 serves also recycled after separation of the products of the isomerization zone) stream, containing mainly n-alkanes. Contact the gas from the P-1 display line 2, is cooled to a predetermined temperature and is fed to the isomerization zone P-2. On the line between areas 1 and 2 can be installed separating system C for the Department carried out particles of dehydrating catalyst of the criminal code. In the zone(s) P-1 and/or P-2 can be served water vapor B (lines 4 and 4'), and in zone P-2 through line 3 - additional hydrocarbon stream F', containing predominantly n-alkenes.

From the reactor P-2 output contact gas containing at least n-alkanes, n-alkenes, isoalkane and hydrogen.

Contact of the gas from the isomerization zone P-2 through line 5 serves in the WU site selection hydrocarbons, whence remove threads of light and heavy by-products and eliminate hydrocarbon mixture containing at least n-alkane(s), n-alkenes and isoalkane(s) that line 6 serves in the node JJA to extract isoalkanes (tert-alkenes). In the node JJA may be filed with the additional flow(s) of reagent(s) DR1 (stream 6A).

From node JJA on leaderjewry mostly n-alkane(s) and n-alkenes, served in the node extraction of n-alkenes IN. In the node INA may be filed with the additional flow(s) of reagent(s) DP2 (thread 8A). From INA output stream 9 containing predominantly n-alkane(s), which is sent to the dehydrogenation zone P-1. If the node occurs IN the allocation of n-alkenes in the unconjugated form (for example, extractive distillation), the stream 10 containing predominantly n-alkenes, send to the site isomerization of P-2. If the node occurs IN the chemical binding of n-alkenes, products, binding of n-alkenes, for example in the form of dimers and/or trimers, and/or second-alcohol and/or alkyl-second-alilovic esters, and/or diver-alilovic esters form or another, output line 11.

In Fig. 2 diagram, dehydrogenation, isomerization and separation of hydrocarbons from the contact strip similarly shown in Fig. 1. In contrast to Fig. 1 isolated from contact hydrocarbon gas mixture (stream 6) is subjected to separation by distillation in the presence of a polar agent (extractive distillation) node in the ER. Allocated(e) in the host ER alkane(s) recycle node dehydrogenation on line 7. The remaining hydrocarbons (predominantly a mixture of n - and isoalkanes) after distillation of the polar agent for line 8 is sent to the TGS is C JJA on line 9 output connections isoalkanes (mainly connection tert-alkenes). On line 10 output stream containing predominantly n-alkenes, which recycle in P-2 through line 10' and/or possibly removed from the system through line 11.

In Fig. 3 is a diagram of the processing of hydrocarbon mixtures containing alkanes with different numbers of carbon atoms (for example, processing a mixture of F containing alkanes C4and C5(mostly normal structure).

In terms of sites of gas-phase dehydrogenation, gas-phase isomerization, and the selection of a mixture of hydrocarbons, C4and C5from the contact strip in the area of WU scheme similar to that shown in Fig. 1 and 2.

In contrast to Fig. 1 and 2 output from WU stream 6 containing predominantly hydrocarbons, C4and C5: alkanes C4, alkenes C4, alkanes C5and alkenes C5is subjected to rectification in a column K. the Top of the column output stream 6A, containing predominantly hydrocarbons, C4and bottom output stream 6B, containing predominantly hydrocarbons, C5.

The thread 6A is served in the node extraction isobutene (node IMU), which can be lodged with the additional flow(s) of reagent(s) DR1. From the ISS thread 7A output connection(I) isobutene (NIB) and output stream 8A, containing at least butane and NY reagent DP2.

From the zone INB output stream 9A, containing predominantly butane (mainly n-butane), which recycle in P-1. Can also be output stream 10A, mainly containing n-butenes, which recycle in P-2, and/or stream 11A containing the compound(I) n-butenes.

Stream 6B is sent to the node extraction of isopentanol node (IIP), which can be enjoyed the additional flow(s) of reagent(s) DR. From SMPS stream 7B display the compound(I) of isopentanol (SIP) and flow 8B remaining hydrocarbon mixture is sent to the node extracting n-pentanol node (IEF), which can be lodged with the additional flow(s) of reagent(s) DR.

From node INP output stream 9B, containing predominantly pentane (mainly n-pentane), which recycle in P-1. Can also be removed stream 10B containing predominantly n-pentane that recycle in P-2, and/or stream 11B containing compounds n-pentanol.

Example 1.

As raw materials use of n-butane. The processing carried out according to Fig. 1. The dehydrogenation zone P-1 is carried out in a "boiling" layer industrial fine alimohammadi catalyst IM-2201. The isomerization reaction zone P-2 is carried out in stationary is">

Isolated from contact gas (stream 5) node WU mixture (stream 6) is subjected in the area JJA liquid communication at 80oC with an aqueous solution containing 10 wt. % formaldehyde and 4 wt.% phosphoric acid, and the distillation of the unreacted hydrocarbon from the resulting products.

From the block JJA output stream 7 containing generated from isobutene products: 4,4-dimethyldioxanes-1,3, 3-methylbutanol-1,3 and tert-butanol, which can further be used for production of isoprene, and output a stream 8 containing unreacted in JJA hydrocarbons, predominantly butane(s) and the butenes.

Stream 8 is sent to the extraction block n-butenes, which is carried out by extractive rectification with dimethylformamide. From INA output stream 9 containing predominantly butane (mainly n-butane and a stream 10 containing predominantly n-butenes, which recycle in P-2.

Characteristics of the main hydrocarbon streams and process parameters is given in tab. 1.

Example 2.

As raw materials use of n-butane. The processing carried out according to Fig. 1. The dehydrogenation zone P-1 is carried out in a stationary layer of granulated alimohammadi catalyst, IIA coated on the surface of the silicon compounds (by processing tetraethoxysilane and subsequent annealing).

Highlighted in the area WU mixture is subjected in the area JJA liquid communication with methanol in the presence of sulfonate catalyst Amberlyst-15, which is crosslinked porous granular sulfurimonas of styrene and divinylbenzene (static exchange capacity SOY of 4.7 mEq+/g of catalyst. Unreacted hydrocarbons is distilled off from the resulting tert-butyl ether and mixtures of methanol and sent to the zone IN.

In the area IN extractive distillation with acetonitrile produce a stream containing predominantly n-butane, returned to the zone P-1, and a stream containing predominantly n-butenes returned to the zone P-2.

Results see table. 1.

Example 3.

As raw materials use of n-butane. The processing carried out according to Fig. 2. The dehydrogenation zone P-1 exercise on a stationary platypodinae catalyst (0.3% of platinum on the carrier), isomerization in zone P-2 is performed on a stationary catalyst obtained by coating on aluminum oxide (media) compounds of silicon and 0.1% of palladium.

The selected node WU hydrocarbon mixture (stream 6) share in the ER node extractive rectification with dimethylformamide. Sweat is of dimethylformamide produce a mixture of hydrocarbons, that is mostly isobutene and n-butenes, which is sent to the zone extraction isobutene (JJA). Isobutene is extracted by contacting the mixture with water, molded sulfocationites catalyst KU-FPP (which is a porous mixture of sulfonated copolymer of styrene with divinylbenzene and polypropylene, molded in the form of rings with a length of 8 mm and an external diameter of 6 mm), SOY=3.3V, followed by distillation of the unreacted hydrocarbons containing predominantly n-butenes (stream 10), which return in P-2, and the allocation of stream 9 containing predominantly tert-butanol.

Results see table. 1.

Example 4.

As raw materials use of n-pentane. The processing carried out according to Fig. 2. The dehydrogenation of n-pentane in the node P-1 is carried out in a "boiling" layer alimohammadi catalyst, isomerization node P-2 in the presence of a catalyst containing silica gel coated on the surface of aluminum oxide.

The hydrocarbon mixture is highlighted in the WU site of contact of the gas divided by extractive rectification with dimethylacetamide. Produce a stream containing predominantly n-pentane, which is returned to the dehydrogenation zone, and the flow of the hydrocarbon centany by contact with methanol in the presence of molded sulfonic cation exchanger'KEEFE (SOY= 3,6) with the formation of methyl tert-amyl ether (MTAE). From JJA output stream MTAA (stream 9) and the stream 10 containing predominantly n-pentane that line 10' recycle to the isomerization zone P-2.

Results see table. 2.

Example 5.

As a raw material, a mixture of n-butane and n-pentane in a ratio of 1:1 (wt.).

The processing carried out according to Fig. 3. The dehydrogenation is carried out in the "boiling" layer alimohammadi catalyst, isomerization node P-2 - aluminum oxide coated on the surface of silicon oxide and 0.1% of palladium, upon application to the P-2 in raw stream of 0.1% of carbon tetrachloride.

From the gas stream 5 in the zone of the hydrocarbon extract mixture (stream 6), containing predominantly butane, pentane, butenes and pentane, which is subjected to rectification in a column K. column To the top output stream 6A, containing predominantly hydrocarbons, C4and the lower stream 6B, containing predominantly hydrocarbons, C5.

The thread 6A is sent to the node extraction isobutene (IMU), which is carried out mainly dimerization of isobutene in the presence of fine-grained sulfonic cation exchanger KU-23 (which is based on sulphonated copolymer of styrene with divinylbenzene), SOY = 4,1, and distilled neprology and stream 8A, containing butane and n-butenes, which is sent to the node extraction of n-butenes (INB).

Node INB n-butenes is subjected to dimerization in the presence of fine-grained sulfocationites catalyst Amberlyst-38 (SOY=5,3). From INB output stream 9A, containing predominantly n-butane, which recycle in P-1, and the stream 11 containing predominantly dimers of n-butenes.

Stream 6B is sent to the node extraction of isopentanol (IIP), where in the presence of sulfonate catalyst Amberlyst-15 (SOY=4,7) in contact with ethanol. Isopentane interact with ethanol to form ethyl-tert-pentalogy ether (ATPA). From the SMPS output of ATPA (stream 7B, SIA) and a mixture of pentane and n-pentanol (thread 8B), which is sent to block the IEF. In the IEF carry out the separation of the mixture by extractive rectification with dimethylformamide. From the block INP output stream 9B, containing predominantly n-pentane, which recycle in P-1, 10B, containing predominantly n-pentane that recycle in P-2.

Results see table. 3.

1. The method of obtaining compounds isoalkanes from n-alkanes by feeding n-alkanes in the area of catalytic dehydrogenation, gas contact zone dehydrogenation in a catalytic zone Isom is, trichosis the fact that in the isomerization zone is used, the catalyst is aluminum oxide coated with silicon compounds, and/or halides, and/or a variable valence metal, preferably palladium, and isolated from the gas contact zone isomerization mixture containing mainly hydrocarbons with a carbon number of atoms, similar to the source(s) n-alkane(s), share or by chemical binding of tert-alkene(s) in the presence of an acidic catalyst with water and/or alcohol(s), and/or formaldehyde, and/or dimerization, followed by the separation of a mixture of unreacted hydrocarbons, retrieved from the n-alkenes by distillation with a polar(s) agent(s) and/or chemical binding of water and/or alcohol(s), and/or dimerization and n-alkenes returned to the dehydrogenation zone and possible n-alkenes in the isomerization zone or separated by distillation with a polar(s) agent(s) and allocated(e) alkane(s) returned to the dehydrogenation zone, from fight off polar agent mixture is extracted tert-alkenes by chemical binding in the presence of an acidic catalyst with water and/or alcohol(s), and/or formaldehyde, and/or dimerization and you can stream containing primarily to the C, supplied from the dehydrogenation zone to the isomerization zone, is cooled to a temperature less than 500oC, preferably up to 350 - 450oC.

3. The method according to p. 1, characterized in that the isomerization zone introduce additional(s) stream(s) containing(e) n-alkenes and/or water.

4. The method according to p. 1, characterized in that as the source of n-alkanes using n-butane and/or n-pentane.

5. The method according to p. 1, characterized in that when using the original mixture of n-butane and n-pentane from the selected contact of the gas mixture are distillation stream containing predominantly hydrocarbons, C4and a stream containing predominantly hydrocarbons, C5and carry out the separation of each of these flows.

6. The method according to p. 1, characterized in that the dehydrogenation of n-alkene(s) is carried out in a stationary or fluidized bed alimohammadi and/or platypodinae catalyst.

 

Same patents:

The invention relates to the field of petrochemicals, in particular for reactors for dehydrogenation of paraffin hydrocarbons

The invention relates to the field of automation of production processes and can be used in the petrochemical industry in the production of styrene by dehydrogenation of ethylbenzene, styrene by dehydration of methylphenylcarbinol, obtaining a-methylstyrene by dehydrogenation of cumene in the production of divinylbenzene by dehydrogenation of diethylbenzene, etc

The invention relates to the petrochemical industry and can be used in the production of isoprene by dehydrogenation of isoamylenes

The invention relates to a chemical reactor and method using a chemical reactor, which is used with the installation of the heat transfer walls, inside the reactor, which will maintain the temperature inside the reactor at the desired intervals during the reaction

The invention relates to the field of chemistry, in particular to a method for producing olefinic hydrocarbons used in the future to obtain the basic monomers of the IC, as well as in the production of polypropylene, methyltrichlorosilane ether, etc

The invention relates to methods for producing gasoline alkylate is high - octane and organic component of gasoline and can be used in refining and petrochemical industries

The invention relates to distillate material having a high cetane number, which can be used as a diesel fuel or a blend component for him, but also to the process of obtaining this distillate

The invention relates to distillate material having a high cetane number and suitable as diesel fuel or as a component of mixed diesel fuel, as well as to a method for production of distillate

The invention relates to the isomerization of n-paraffin hydrocarbons and can be used in refining and petrochemical industries

The invention relates to the isomerization of olefins and can be used in the petrochemical industry

The invention relates to a method of hydroisomerization n-paraffins with a long chain

The invention relates to catalytic methods hydroperiod hydrocarbons, and in particular to methods of hydroperiod oil fractions with a high content of normal paraffins in the environment of hydrogen to obtain products with a high content of ISO-paraffins

The invention relates to chemical technology, in particular to methods for alkylbenzene by alkylation isoparaffins olefins and can be used in the refining and petrochemical industry
Up!