WO2003012011A1

WO2003012011A1 - Method for obtaining high octane gasoline and device for its implementation (variants)

Info

Publication number: WO2003012011A1
Application number: PCT/RU2001/000452
Authority: WO
Inventors: Genrirh Falkevich; Nikolay Rostanin; Olga Malova
Original assignee: Genrirh Falkevich; Nikolay Rostanin; Olga Malova
Priority date: 2001-08-02
Filing date: 2001-10-29
Publication date: 2003-02-13
Also published as: RU2186829C1

Abstract

The present invention relates to the methods for obtaining gasoline hydrocarbons from lower olefins and can be used in the oil processing and petrochemical industries. In the embodiment of the present invention the raw material that contains at least one of the C1-C6 olefins is supplied to the reaction aera for contacting with a steady state acid catalyst based on a pentasil group ceolite, the olefins contained in the raw material are oligomerized to obtain a flow of the reaction products that contain C5+ gasoline fraction hydrocarbons, said product flow is separated to obtain gasoline and a flow of C1-C4 hydrocarbons, said C1-C4 hydrocarbons being further mixed with the flow of the raw materials, the olefins containing raw material is mixed with the benzene containing reforming gasoline fraction that boils below 85 °C, the olefins to benzene ratio in the final mixture being less than 0.5 mole/mole, and said oligomerization reaction is performed under the conditions that provide for at least partial alkylation of said benzene.

Description

Method for Obtaining High Octane Gasoline and Device for its Implementation

(Variants)

The present invention relates to the methods for obtaining gasoline hydrocarbons from lower olefins and can be used in the oil processing and petrochemical industries.

The byproducts of oil processing technology include a large number of paraffin and olefϊn mixtures that are gaseous under reference conditions. These mixtures can be disposed using different methods. One way to solve the task of disposing these olefm-containing gas mixtures is processing the olefins to motor fuel components.

Light olefins can be used for alkalizing benzene that is a detrimental constituent in gasoline fractions (US No. 4209383, US No. 5336820).

Known is a method of processing light olefϊn containing fuel gas and liquid catalyst enhanced reforming in a reactor with a fluidized ceolite catalyst bed (US No. 4827069) that comprises the steps of converting C₄_ olefins to Cs₊ gasoline fraction hydrocarbons and converting Cό-Cg aromatic hydrocarbons to C₇-Cπ aromatic hydrocarbons due to the contact of the raw materials with catalyst particles, characterized in that the catalyst particles have known density and sizes and that the process occurs under the turbulent catalyst bed conditions. Gasoline derived in this process has a higher octane number that liquid reforming products and olefin containing gasoline that is derived from olefin containing raw materials by oligomerization. The turbulent conditions that are maintained in the catalyst bed allow flexible control of the process temperature and provide for an optimum product distribution.

Known is a method (US No. 5336820) of enhanced alkylation of benzene containing gasoline with C₂-C₅ olefins that provides for the production of low-

3AMEHflI0πiHH JIHCT (IIPABHJIO 26) benzene gasoline and is characterized in that it comprises sequential steps of contacting the gasoline raw material with a solid state catalyst that cause the alkylation of benzene contained in the raw material with the olefins in order of decreasing their oligomerization activity, i.e. first with C3-C5 olefins and further with ethylene.

The C₂-C₄ olefins can be oligomerized in contact with ceolite catalysts to gasoline and diesel fuel components. The specific properties of the catalyst used and the unique technology provide for olefin oligomerization with a high selectivity with respect to desired products (S.A. Teibek, Oil, Gas and Oil Chemistry Abroad, 1985, No. 9, p. 67-70).

The closest analogue of the high octane gasoline production method claimed in the present invention is Russian Patent No. 2135547 that describes the method of increasing the yield of the C₅₊ gasoline fraction during the oligomerization of lower olefins. In one embodiment of this method the oligomerization of olefin containing C₃ and C₄ or sole C₄ hydrocarbon fractions to gasoline hydrocarbons is performed by contacting the raw material with a oligomerization catalyst that comprises a pentasil group ceolite, with recycling of part of the C₁-C₄ hydrocarbon flow derived from the partially condensed product during its vapor-liquid separation and part of the C4 fraction derived from the product by rectification. Enrichment of the raw material with isobutane increases the yield of liquid hydrocarbons to modified olefins, but the fraction of the Cι-C₂ hydrocarbons may reach to 10 wt.%.

The technical task solved by the present invention is providing a new method of disposing the mixtures of olefin containing gases derived during oil processing. The technical result achieved by the present invention is obtaining high octane gasoline from mixtures of olefin containing gases that are derived during oil processing, characterized in a reduced amount of dry gases forming as a result (methane and ethane) as compared to other known methods.

It is suggested to achieve said result by using the following method of obtaining high octane gasoline. Said methods comprises the steps of supplying the raw material that contains C₂-C₄ olefins, i.e. one of them or a mixture of two or more olefins, to the reaction area with a steady-state pentasil group ceolite acid catalyst, performing the oligomerization of the supplied raw olefins that produces a flow of reaction products that contain C5₊ gasoline fraction hydrocarbons, separation of said flow of reaction products to obtain gasoline and a flow of C₁-C₄ hydrocarbons with further mixing of said flow of -C₄ hydrocarbons with the flow of the raw material, characterized in that the olefin containing raw material is additionally mixed with the catalytic reforming gasoline fraction (boiling temperature max. 85 °C) that contains benzene, the olefins-to-benzene ratio in the final mixture is at leas 0.5 mole/mole, and said oligomerization reaction is performed under the conditions that provide for alkylation of at least part of said benzene. According to one of the embodiments of the method, the benzene containing fraction of reforming gasoline is mixed with the raw material that contains ethylene, the interaction of said raw material with said catalyst is performed in two reaction areas, and the reaction is performed in such a way that in one of the reaction areas the ethylene containing raw material interacts with the catalyst, the flow of reaction products obtained as a result of said interaction in the first reaction area is additionally mixed with the propylene and/or butylenes containing raw material, and the resultant mixture is supplied to the second reaction area, the mixture temperature at the input of the first reaction area being maintained higher than the rmxture temperature at the input of the second reaction area. According to another embodiment of the method, the benzene containing fraction of reforming gasoline is mixed with the raw material that contains ethylene, the interaction of said raw material with said catalyst is performed in three reaction areas, and the reaction is performed in such a way that in one of the reaction areas the ethylene containing raw material interacts with the catalyst, the flow of reaction products obtained as a result of said interaction in the first reaction area is additionally mixed with the propylene containing raw material, the resultant rmxture is supplied to the second reaction area, the flow of reaction products obtained as a result of the interaction in the second reaction area is additionally mixed with the raw material that contains butylenes, and the resultant mixture is supplied to the third reaction area, the mixture temperature at the input of the first reaction area being maintained higher than the mixture temperature at the input of the second reaction area. Also possible is embodiment wherein the raw material is interacted with the catalyst in at least two parallel reaction areas with ftirther mixing of the reaction products. The flow of the reaction products can be further additionally separated to derive the benzene containing C₆ hydrocarbon fraction that is further mixed with the raw material in at least one of the reaction areas. For the latter embodiment the benzene containing Cβ hydrocarbon fraction can be hydrated for selective olefin hydration before being mixed with the raw material.

During the contact of the olefin containing raw material and the benzene containing fraction of the catalytic reforming products with the ceolite containing acid catalyst cause the oligomerization of the olefins to C5-C9 hydrocarbons, mainly paraffins, olefins and aromatic hydrocarbons, and alkylation of the benzene to Cg-Cio alkylbenzenes. The catalytic conversion of said mixed raw material differs from the oligomerization of olefin containing raw materials performed under similar conditions in a lower yield of methane and ethane and a higher yield of C5₊ gasoline fraction hydrocarbons, the latter yield being determined as the difference in the content of this fraction in the raw material and in the reaction product, or as the ratio of these contents.

The olefin containing raw material can be mixtures of C₁-C₄ hydrocarbons that contain at least one of the C2-C₄ olefins and almost no dienes. In the preferred embodiment of the present invention the raw material is oxygen containing. Typical raw materials are the olefin containing fractions of catalytic cracking end gas. The benzene containing fraction of reforming gasoline with a maximum boiling temperature of 85 °C is derived by rectification. The reforming gasoline fraction with a maximum boiling temperature of 85 °C may also contain C5-C7 paraffins. The olefins-to benzene ratio in the raw material should be not less than 0/5 mole/mole, preferably in the range 1.5 to 20 mole/mole.

The acid catalysts according to the present embodiment of the method contain pentasil group ceolite and are active in the oligomerization of lower olefins to gasoline hydrocarbons. Acid properties are inherent to the hydrogen and the mixed cation substituted forms of ceolite. Said catalysts may also contain metals and metal oxides, as well as phosphorus or boron oxides that are introduced with known methods and affect the catalytic properties and stability of catalysts. Along with aluminum silicate ceolites, silicates of other elements with a pentasil structure having similar catalytic properties can also be used in the present embodiment. The synthesis methods and structure of these materials are widely described in literature and are well-known.

The contact of the raw material with the steady-state catalyst bed is performed under the olefin oligomerization and benzene alkylation conditions that are determined by the properties of the catalyst, usually at 280-500 °C, 0.6-2.5 MPa and raw material volume flow rate 0.5-8 1/h. The reaction area conditions should provide for the desired convertion degree of olefins and benzene and be maintained strictly enough to limit the product range to gasoline hydrocarbons.

The C5₊ gasoline fraction hydrocarbons derived by catalytic conversion of the mixture of the olefin containing raw material and the benzene containing fraction of catalytic refoπning products contain less benzene than the mixture of the benzene containing fraction of catalytic reforming products and the olefin containing raw material ohgomerization product (the C5₊ gasoline fraction hydrocarbons), because the conversion of the mixed raw material involves benzene alkylation to high octane Cg-Cio aromatic hydrocarbons. The knock characteristic of the mixed raw material conversion product as determined during bed tests and analytical methods proved to be higher than for the mixture of liquid oligomerization and reforming products.

The activity of the olefins in the oligomerization reaction may be different and increases from ethylene to butylenes, therefore to provide for high catalyst activity the olefins areoligomerized at different optimum process temperatures, this temperature being higher for ethylene. When close-cut olefins fractions, e.g. C₂ and C₃-C₄ or C₂, C3 and C₄, are used in the present embodiment of gasoline production method as the olefϊn containing raw material, the contact of the raw material and the catalyst can be performed in two or three reaction areas, respectively, under the conditions that are favorable for each of the olefin containing fractions. For example, the preferred temperature of contact with the catalyst for the ethylene containing raw material is max. 500 °C, for the propylene and butylenes containing raw materials these temperatures are max. 460 and 440 °C, respectively. This stepwise mode of the catalytic process results in a higher activity of the catalyst with an increase in the conversion temperature of the olefin containing raw material, and a higher stability of the catalyst with a decrease of the process temperature. Gasoline production in two reaction areas is preferred when one of the raw material fractions is the ethylene containing fraction.

There are two embodiments of the stepwise raw material conversion process.

According to one of the embodiments the fraction of liquid reforming products is mixed with the olefϊn containing raw material supplied to the first reaction area, and the product is supplied to the next reaction area to provide for sequential conversion of the olefins and benzene in these reaction areas. As the conversion temperature is the key factor in the coke formation for this type of raw material, increasing the catalyst stability requires reducing the mean temperature in the reaction areas as the unsaturated hydrocarbon products are accumulated in the direction from the first reaction area to the subsequent ones.

According to the other embodiment, the olefins are converted in two

by mixing the fraction of liquid reforming products with the olefin containing raw material that is supplied to each of the reaction areas, the products being mixed and supplied to the separation stage.

When gasoline is obtained from two olefin containing fractions one of which additionally contains ethylene, with consecutive conversion of the reaction products in two reaction areas, the ethylene containing raw material is primarily mixed with the benzene containing fraction of reforrning gasoline, and the resultant mixture is contacted with the catalyst in the first reaction area, the flow of the first area reaction products is mixed with the propylene and/or butylenes containing raw material, and the resultant mixture is contacted with the catalyst in the second reaction area, the raw material mixture at the input of the first reaction area being higher than the raw material mixture at the input of the second reaction area.

When gasoline is obtained from three hydrocarbon fractions that contain ethylene, propylene and butylenes, respectively, with consecutive conversion of the raw material in two reaction areas, the ethylene containing raw material is primarily mixed with the benzene containing fraction of reforming gasoline, and the resultant mixture is contacted with the catalyst in the first reaction area, the flow of the first area reaction products is mixed with the propylene containing raw material, and the resultant mixture is contacted with the catalyst in the second reaction area, the flow of the second area reaction products is mixed with the butylenes containing raw material, and the resultant mixture is contacted with the catalyst in the third reaction area, the raw mixture temperature at the input of the consecutive reaction areas being reduced in the direction from the first to the third reaction area.

The olefins oligomerization and benzene alkylation reactions are exothermal. To avoid overheating of the reaction areas the raw materials are diluted with C₁-C₄ paraffins derived from the reaction products. In the preferred embodiment of the present method, the flow of the reaction products is separated as follows. The flow is cooled to partial condensation of its components, and the cooled flow is subjected to vapor-liquid separation to obtain a gaseous flow that contains C₁-C₄ hydrocarbons and a liquid flow that mainly contains C₃₊ hydrocarbons, said liquid flow being fractionated to derive €5₊ gasoline and the C3-C₄ hydrocarbon flow and parts of the -C₄ and C3- C₄ hydrocarbon flows are mixed with the raw material at least in one of the reaction areas.

For the present gasoline production method the conversion degree of benzene that is contained in the raw material fraction of liquid reforming products depends on process conditions and raw material composition, and in the preferred embodiment it is above 30%. For more complete benzene conversion the benzene containing fraction, i.e. the C_ hydrocarbons fraction, is separated from the flow of the reaction products and is mixed with the raw material at least in one of the reaction areas. In the preferred embodiment of a two- or three-stage process the recycled benzene containing fraction is supplied to the reaction area with the lower raw material conversion temperature.

The benzene containing fraction separated from the product flow also contains olefins that form during the oligomerization of the primary raw olefins. The olefins content depends mainly on the olefins to the reforming products fraction ratio in the raw material and on the benzene content in the reforming products fraction and Hie conversion degree of that benzene. The presence of C₅₊ olefins in the raw material is undesired as it enhances the coke formation in the catalyst. To remove the olefins from the circulated benzene fraction it is hydrated, before being mixed with the raw material, to selectively hydrate olefins on an aluminum-cobalt-molybdenum or an aliuninum-nickel- molybdenum catalyst bed to a known technology used for the hychorefϊning of secondary gasolines (G.N. Maslaybsky and R.N. Shapiro, Catalytic Reforming of Gasolines, Leningrad, Khimiya, 1985, p. 109-118; M.V. Landau, Chemistry and Technology of Fuels and Oils, 1991, No. 1, p. 8-10).

The methods according to the present invention can be implemented using the device as described below. The device comprises a first heat exchanger the first input of which is connected to the ethylene containing fraction pipeline, the reforming gasoline fraction pipeline, the hydrated Cβ product fraction pipeline and the pipeline of the part of the C1-C₄ hydrocarbons flow obtained by vapor-liquid separation of the cooled product flow or, possibly, part of the C1-C4 hydrocarbons flow and hydrogen. The first input of the first heat exchanger is connected to the first input of the first furnace, the first output of which is connected to the input of the first reactor, the output of which is connected via a pipeline to the input of the second reactor, the output of which is connected via a pipeline to the input of the third reactor, the output of which is connected via a pipeline to the second input of the first heat exchanger and to the first inputs of the second and third heat exchangers. The second input of the second heat exchanger is connected to the propylene containing fraction pipeline and the recycled flow pipeline, said recycled flow comprising part of the C1-C4 hydrocarbons flow (and, possibly, part of the C₁-C₄ hydrocarbons flow and hydrogen) separated from the product flow by vapor-liquid separation and rectification, the first output of the second heat exchanger is connected to the second input of said first furnace and via the second output of said first furnace to the pipeline that connects the output of the first reactor to the input of the second reactor. The second input of the third heat exchanger is connected to the butylenes containing fraction pipeline and the recycled flow pipeline, said recycled flow comprising part of the C₁-C₄ hydrocarbons flow (and, possibly, part of the C₁-C₄ hydrocarbons flow and hydrogen) separated from the product flow by vapor-liquid separation and rectification, the first output of said third heat exchanger is connected to the third input of said first furnace and via the third output of said furnace to the pipeline that connects the output of the second reactor to the input of the third reactor. The second outputs of the first, second and third heat exchangers are connected to the input of an air cooler, the output of which is connected to the input of a water cooler. The output of said water cooler is connected to the input of the first separator. The first output of said first separator provides for the output of a balance amount of said recycled flow comprising part of the C₁-C₄ hydrocarbons flow (and, possibly, part of the C₁-C₄ hydrocarbons flow and hydrogen) and supply for mixing via the first compressor, upstream of which an input can be provided for hydrogen or a hydrogen containing gas, said hydrogen containing gas comprising at least 85 vol.% of hydrogen, part of the C₁-C₄ hydrocarbons flow (and, possibly, part of the C₁-C₄ hydrocarbons flow and hydrogen) separated from the product flow by vapor-liquid separation with the mixture of C3-C4 hydrocarbons supplied from the stabilization stage, or the ethylene containing raw material pipeline. The second output of said first separator is connected via a fourth heat exchanger to the first input of the ethane separation column, the first output of winch is used for the removal of dry gas that is recycled, at least partially, via the second input back to the column, and the one partially removed from the plant. The second output of said ethane separation column provides for partial recycling of the unstable gasoline via the third input and for the supply of said unstable gasoline via the fifth heat exchanger and the first input to the stabilization column. The first output of said stabilization column provides for recycling the mixture of C3-C4 hydrocarbons (the upper column effluent product) via the second input of the stabilization column, for mixing said mixture of hydrocarbons with the product effluent from said first compressor and for obtaining an end product, i.e. the commercial propane-butane fraction. The second output of said stabilization column provides for connecting to the third input of said stabilization column and to the input of the sixth heat exchanger. The output of said sixth heat exchanger is connected to the first input of the rectification column. The first output of said rectification column provides for partial recycling of the main end product, i.e. nonarornatic C5-C6 hydrocarbons contained in gasoline, to said rectification column and for the uptake of said main product as an end product, the second output of said rectification column provides for the uptake of the benzene containing fraction as an end product and for connection to a hydration module that is implemented at the input of the seventh heat exchanger, directly upstream of which a second compressor is installed. The third output of said rectification column provides for partial recycling of the vat residue (C7+ gasoline fraction hydrocarbons) to said rectification column and for the output of said vat residue as an end product. The first output of said seventh heat exchanger is connected to the input of the second separator, the first output of which is connected to the first input of the eighth heat exchanger and the second output of which is connected to the input of the second compressor, to which the hydrogen or hydrogen containing gas pipeline and the partial hydrogen containing gas removal pipeline are connected. The second output of said seventh heat exchanger is connected to the input of the second furnace, the output of which is connected to the input of the hydration module reactor, the output of which is connected to the second input of the seventh heat exchanger. The first output of said eighth heat exchanger is connected to the first input of a stripping column, the first output of which provides for connection to the second input of said stripping column and for output of the hydrogen containing gas dissolved in the liquid hydrogenate as a semiproduct. The second output of said stripping column provides for partial recycling of the stable hydrated C hydrocarbons fraction to said column and for partial supply of said hydrated C hydrocarbons fraction to the second input of the eighth heat exchanger with further supply via the second output of the eighth heat exchanger for mixing with the ethylene containing raw material fraction. All the connections between the elements of the plant and the means for the input and output of the raw materials, semiproducts and the products are in the form of pipelines.

The method can also be implemented using the device as described below. The device comprises a first heat exchanger the first input of which is connected to the ethylene containing fraction pipeline, the reforming gasoline fraction pipeline, the hydrated Cβ product fraction pipeline and the pipeline of the recycled part of the C1-C4 hydrocarbons flow (or, possibly, part of the - C₄ hydrocarbons flow and hydrogen) obtained by vapor-Uquid separation of _ _

14 the cooled product flow, the first output of said first heat exchanger is connected to the first input of the furnace, the first output of which is connected to the input of the first reactor, the output of which is connected to the second input of said first heat exchanger, the second output of which is connected to the second input of an air cooler. The first input of said second heat exchanger is connected to the propylene containing fraction pipeline, the reforming gasoline fraction pipeline and the pipeline of the recycled part of the C1-C4 hydrocarbons flow (or, possibly, part of the C₁-C4 hydrocarbons flow and hydrogen) obtained by vapor-liquid separation of the cooled product flow, the first output of said second heat exchanger is connected to the second input of the furnace, the second output of which is connected to the input of the second reactor, the output of which is connected to the second input of said second heat exchanger, the second output of which is connected to the input of the air cooler. The first input of the third heat exchanger is connected to the butylenes containing fraction pipeline, the reforming gasoline fraction pipeline and the pipeline of the recycled part of the C₁-C₄ hydrocarbons flow (or, possibly, part of the C₁-C₄ hydrocarbons flow and hydrogen) obtained by vapor-liquid separation of the cooled product flow, the first output of said third heat exchanger is connected to the third input of the furnace, the third output of which is connected to the input of the third reactor, the output of which is connected to the second input of the third heat exchanger, the second output of which is connected to the input of the air cooler, the output of which is connected to the input of a water cooler. The output of said water cooler is connected to the input of a separator. The first output of said separator provides for the removal of a balance amount of -C₄ hydrocarbons flow (or, possibly, C₁-C₄ hydrocarbons flow and hydrogen) and is connected to the pipeline of the recycled part of the C₁-C₄ hydrocarbons flow (or, possibly, part of the C₁-C₄ hydrocarbons flow and hydrogen) obtained by vapor-liquid separation of the cooled product flow via a compressor, upstream of which an input can be provided for hydrogen or a hydrogen containing gas, said hydrogen containing gas containing at least 85 vol.% of hydrogen, and for the pipeline of C3-C₄ hydrocarbons derived by stabilization. The second output of said separator is connected via the fourth heat exchanger to the first input of the ethane separation column, the first output of which is used for the removal of dry gas that is at least partially recycled via the second input back to the column and the one partially removed from the plant. The second output of said column provides for partial recycling of unstable gasoline via the third input back to the column and for the supply of said unstable gasoline via the fifth heat exchanger and the first input to the stabilization column. The first output of the stabifization column provides for the recycling of part of the mixture of C3-C4 hydrocarbons (the upper column effluent product) via the second input of the stabilization column, for mixing said mixture of hydrocarbons with the product effluent from said first compressor and for obtaining an end product, i.e. the commercial propane-butane fraction. The second output of said stabilization column provides for connecting to the txiird input of said stabilization column and to the input of the sixth heat exchanger. The output of said sixth heat exchanger is connected to the first input of the rectification column. The first output of said rectification column provides for partial recycling of the main end product, i.e. nonaromatic Cs-C₆ hydrocarbons contained in gasoline, to said rectification column and for the uptake of said main product as an end product, the second output of said rectification column provides for the uptake of the benzene containing fraction as an end product and for the supply of said benzene containing fraction to the first inputs of the first three heat exchangers. The third output of said rectification column provides for partial recycling of the vat residue to said rectification column and for the output of said vat residue as an end product, i.e. C₇₊ gasoline fraction hydrocarbons. All the connections between the elements of the plant and the means for the input and output of the raw materials, semiproducts and the products are in the form of pipelines.

The first described embodiment of the invention is presented in Fig. 1, and the second embodiment is present in Fig. 2.

In Fig. 1, 1 is the first heat exchanger the first input of which is connected to the ethylene containing fraction pipeline 2, the reforming gasoline fraction pipeline 3, the hydrated C6 product fraction pipeline 4 and the pipeline 5 of the recycled part of the C1-C₄ hydrocarbons flow (or, possibly, part of the -C₄ hydrocarbons flow and hydrogen) obtained by vapor-liquid separation of the cooled product flow. The first output of the first heat exchanger 1 is connected to the first input of the first furnace 6, the first output of which is connected to the input of the first reactor 7, the output of which is connected via the pipeline 8 to the input of the second reactor 9, the output of which is connected via the pipeline 10 to the input of the third reactor 11, the output of which is connected via the pipeline 12 to the second input of the first heat exchanger 1 and to the first inputs of the second 13 and third 14 heat exchangers. The second input of the second heat exchanger 13 is connected to the propylene containing fraction pipeline 15 and the recycled flow pipeline 16, said recycle^ flow comprising part of the C₁-C₄ hydrocarbons flow (and, possibly, part of the C1-C4 hydrocarbons flow and hydrogen) separated from the product flow by vapor- liquid separation and rectification. The first output of the second heat exchanger 13 is connected to the second input of said first furnace 6 and via the second output of said first furnace 6 and the pipeline 17 to the pipeline 8 that connects the output of the first reactor 7 to the input of the second reactor 9. The second input of the third heat exchanger 14 is connected to the butylenes containing fraction pipeline 18 and the recycled flow pipeline 16, said recycled flow comprising part of the C₁-C₄ hydrocarbons flow (and, possibly, part of the C₁-C₄ hydrocarbons flow and hydrogen) separated from the product flow by vapor-hquid separation and rectification, the first output of said third heat exchanger 14 is connected to the third input of said first furnace 6 and via the third output of said furnace and the pipeline 19 to the pipeline 10 that connects the output of the second reactor 9 to the input of the third reactor 11. The second outputs of the first 1, second 13 and third 14 heat exchangers are connected to the input of the air cooler 20, the output of which is connected to the input of the water cooler 21. The output of said water cooler 21 is connected to the input of the first separator 22. The first output of said first separator 22 provides for the output via the pipeline 24 of a balance amount of C1-C4 hydrocarbons flow (and, possibly, part of the C₁-C₄ hydrocarbons flow and hydrogen) and supply via the pipeline 25 of the mixture of C₁-C₄ hydrocarbons flow (and, possibly, part of the C₁-C₄ hydrocarbons flow and hydrogen) separated from the product flow by vapor-hquid separation via the first compressor 23 to the pipeline 5 and further to the first input of the first heat exchanger 1 and the recycled C₃-C₄ hydrocarbons flow pipeline 16 to obtain the mixture to be supplied to the first inputs of the second 13 and third 14 heat exchangers. The second output of said first separator 22 is connected via the fourth heat exchanger 26 to the first input 27 of the ethane separation column 28, the first output 29 of which is used for the removal of dry gas that is recycled, at least partially, via the second input 30 back to the column 28, and the one partially removed from the plant. The second output 31 of said ethane separation column 28 provides for partial recycling of the unstable gasoline via the third input 32 and for the supply of said unstable gasoline via the fifth heat exchanger 33 and the first input 34 to the stabilization column 35. The first output 36 of said stabilization column 35 provides for recycling the mixture of C3-C₄ hydrocarbons (the upper column effluent product) via the second input 37 of the stabilization column 35, for supplying said mixture via the pipeline 16 for mixing said mixture of hydrocarbons with the product effluent via the pipeline 25 from the first output of said first separator 22 and for obtaining an end product, i.e. the commercial propane-butane fraction. The second output 38 of said stabilization column 35 provides for connecting to the third input 39 of said stabilization column 35 and to the input of the sixth heat exchanger 40. The output of said sixth heat exchanger 40 is connected to the first input 41 of the rectification column 42. The first output of said rectification column 42 provides for partial recycling of the main end product, i.e. nonaromatic Cs-C₆ hydrocarbons contained in gasoline, to said rectification column 42 and for the uptake of said main product as an end product, the second output 44 of said rectification column 42 provides for the uptake of the benzene containing fraction as an end product and for the supply of said benzene containing fraction to the input of the hydration module 45 that is implemented at the input of the seventh heat exchanger 46, directly upstream of which the second compressor 47 is installed. The third output 48 of said rectification column 42 provides for partial recycling of the vat residue to said rectification column 42 via its third input 49 and for the output of said vat residue as an end product (C7₊ gasoline fraction hydrocarbons). The first output of said seventh heat exchanger 46 is connected to the input of the second separator 50, the first output of which is connected to the first input of the eighth heat exchanger 51, and the second output of the second separator 50 is connected via the compressor 47 and the pipeline 52 to the first input of the seventh heat exchanger 46, to which the hydrogen or hydrogen containing gas pipeline 53 and the balance hydrogen containing gas amount removal pipeline 54 are connected. The second output of said seventh heat exchanger 46 is connected to the input of the second furnace 55, the output of which is connected to the input of the reactor 56 of the hydration module 45, the output of which is connected to the second input of the seventh heat exchanger 46. The first output of said eighth heat exchanger 51 is connected to the first input 57 of the stripping column 58, the first output 59 of which provides for connection to the second input 60 of said stripping column 58 and for output of the hydrogen containing gas dissolved in the liquid hydrogenate as a semiproduct. The second output 61 of said stripping column 58 provides for partial recycling of the stable hydrated C₆ hydrocarbons fraction to said column 58 and for partial supply of said hydrated C₆ hydrocarbons fraction to the second input of the eighth heat exchanger 51 with further supply via the second output of the eighth heat exchanger for mixing with the ethylene containing raw material fraction. The additional pipeline 62 can be provided between the output of the first separator and the input of the first compressor for the supply of hydrogen or a hydrogen containing gas (hydrogen content at least 85 vol.%).

All the connections between the elements of the plant and the means for the input and output of the raw materials, semiproducts and the products are in the form of pipelines.

The second embodiment of the invention is presented in Fig. 2, wherein all the elements shown in Fig. 1 have the same digital notations. The device comprises the first heat exchanger 1 the first input of which is connected to the ethylene containing fraction pipeline 2, the reforming gasoline fraction pipeline 3 and the pipeline 5 of the Cι-C₄ hydrocarbons flow (or, possibly, part of the C₁-C₄ hydrocarbons flow and hydrogen) obtained by vapor-liquid separation of the cooled product flow, the first output of said first heat exchanger 1 is connected to the first input of the furnace 6, the first output of which is connected to the input of the first reactor 7, the output of which is connected to the second input of said first heat exchanger 1, the second output of which is connected to the input of the air cooler 20. The first input of the second heat exchanger 13 is connected to the propylene containing fraction pipeline 15, the reforming gasoline fraction pipeline 3 and the pipeline 16 of the C₁-C₄ hydrocarbons flow (or, possibly, part of the C₁-C₄ hydrocarbons flow and hydrogen) obtained by vapor-hquid separation of the cooled product flow, the first output of said second heat exchanger 13 is connected to the second input of the furnace 6, the second output of which is connected to the input of the second reactor 9, the output of which is connected to the second input of said second heat exchanger 13, the second output of which is connected to the input of the air cooler 20. The first input of the third heat exchanger 14 is connected to the butylenes containing fraction pipeline 18, the reforming gasoline fraction pipeline 3 and the pipeline 16 of C₁-C₄ hydrocarbons flow (or, possibly, part of the C₁-C₄ hydrocarbons flow and hydrogen) obtained by vapor-liquid separation of the cooled product flow, the first output of said third heat exchanger 14 is connected to the third input of the furnace 6, the third output of which is connected to the input of the third reactor 11, the output of which is connected to the second input of the third heat exchanger 14, the second output of which is connected to the input of the air cooler 20, the output of which is connected to the input of the water cooler 21. The output of said water cooler 21 is connected to the input of the separator 22. The first output of said separator 22 provides for the removal via the pipeline 24 of a balance amount of C1-C4 hydrocarbons flow (or, possibly, C₁-C4 hydrocarbons flow and hydrogen) and is connected to the pipeline 25 of the C₁-C₄ hydrocarbons flow (or, possibly, part of the C₁-C₄ hydrocarbons flow and hydrogen) obtained by vapor-liquid separation of the cooled product flow via the compressor 23 to the pipeline 5 and further to the first input of the first heat exchanger 1 and pipeline 16 of the recycled C3-C₄ hydrocarbons flow to obtain the mixture to be supplied to the first inputs of the second 13 and third 14 heat exchangers. The second output of said separator 22 is connected via the fourth heat exchanger 26 to the first input 27 of the ethane separation column 28, the first output 29 of which is used for the removal of dry gas that is at least partially recycled via the second input 30 back to the column 28 and the one partially removed from the ethane separation column. The second output 31 of said column 28 provides for parjtjaj recycling of unstable gasoline via the third input 32 back to the column and for the supply of said unstable gasoline via the fifth heat exchanger 33 and the first input 34 to the stabilization column 35. The first output 36 of the stabilization column 35 provides for the recycling of part of the mixture of C3-C₄ hydrocarbons (the upper column effluent product) via the second input 37 of the stabilization column 35, for supplying said mixture via the pipeline 16 for mixing said mixture with the product effluent via the pipeline 25 from the first output of said separator via said compressor 23 and for obtaining an end product, i.e. the commercial propane-butane fraction. The second output 28 of said stabilization column 35 provides for connecting to the third input 39 of said stabilization column 35 and to the input of the sixth heat exchanger 40. The output of said sixth heat exchanger 40 is connected to the first input 41 of the rectification column 42. The first output 43 of said rectification column 42 provides for partial recycling of the main end product, i.e. nonaromatic C₅-C₆ hydrocarbons contained in gasoline, to said rectification column 42 and for the uptake of said main product as an end product, the second output 44 of said rectification column 42 provides for the uptake of the benzene containing fraction as an end product and for the supply of said benzene containing fraction for mixing with the ethylene containing, propylene containing and butylenes containing raw materials in the pipelines 2, 15 and 18, respectively. The third output 48 of said rectification column 42 provides for partial recycling of the vat residue to said rectification column 42 via its third input 49 and for the output of said vat residue as an end product, i.e. C₇+ gasoline fraction hydrocarbons. The additional pipeline 62 can be provided between the output of the separator 22 and the input of the compressor 23 for the supply of hydrogen or a lrydrogen containing gas (hydrogen content at least 85 vol.%). All the connections between the elements of the plant and the means for the input and output of the raw materials, semiproducts and the products are in the form of pipelines.

In the process as described above the rectification columns operate in usual manner, therefore their cold and hot reflux equipment and other pumps are not shown in Figs 1 and 2.

Table 1 presents the yields of the olefϊn containing fraction conversion products and their mixtures with the reforming benzene product fraction that boils below 85 °C, for similar raw material - catalyst contact times.

Table 1

The composition of the raw materials was as follows:

The ethane-ethylene fraction (EEF): 51.2 mol.% C₂H₄ and 48.8 mol.%

The propane-propylene fraction (PPF): 51.6 mol.% Csϊ , 29.2 mol.% C₃H₈ and 19.2 mol.% C₄Hι₀;

Tlie butane-biitylene fraction (BBF): 39.6 mol.% C₄H8, 8.4 mol.% C₄Hι₀, 51.0 mol.% C4H10 and 1.0 mol.% C₃H₈+ CΛ

Fr mixing with the PPF and the BBF, the reforming gasoline fraction was used that contained 21.9% benzene, 8.9% C5H₁₂, 57.4% C₆H₁₄ and 12.8% C₇H₁4.

For mixing with the EEF, the reforming gasoline fraction was used that contained 42% benzene and 58% COH_H. In the course of the experiments the raw material was contacted with Catalyst No. 1 that contained 70% TsVN Grade pentasil group ceohte (B.K. Nefedov, Chemistry and Technology of Fuels and Oils, 1992, No. 3, p. 4) with < 0.1% Na₂0, Si0₂/Al₂0₃ = 71 mole/mole, 1.5% ZnO and 28.5% γ-Al₂0₃; Catalyst No. 2 that contained 70% TsVN Grade pentasil group ceolite (B.K. Nefedov, Chemistry and Technology of Fuels and Oils, 1992, No. 3, p. 36) with 0.15% Na₂0, Si0₂/Al₂0₃ = 28 mole/mole and 30% γ-Al₂0₃; Catalyst No. 3 that contained 65% TsVN Grade pentasil group ceohte with 0.11% Na₂0, Si0₂/Al₂0₃ = 39 mole/mole, 3% B2O3, 28% γ-Al 0₃ and filler.

The experimental results suggest that the conversion of the olefin containing raw material that additionally contains the benzene reforming products fraction is more selective with respect to the C₅₊ gasoline fraction hydrocarbons and less selective with respect to the and C₂ hydrocarbons. In this process benzene is converted to alkylbenzenes.

Thus, if the method of obtaining high octane gasoline according to the present invention is used, the conversion of olefin containing raw materials in the steady state ceolite containing catalyst bed is improved and the quality of liquid catalytic reforming products are also improved (they contain less amount of highly toxic benzene the content of which is limited by the current motor fuel standards).

Claims

What is claimed is a

1. Method of obtaining high octane gasoline comprising the steps of supplying the raw material that contains at least of the C₂-C₄ olefins to the reaction area with a steady-state pentasil group ceohte acid catalyst, performing the oligomerization of the supphed raw olefins that produces a flow of reaction products that contain C₅₊ gasoline fraction hydrocarbons, separation of said flow of reaction products to obtain gasoline and a flow of C1-C4 hydrocarbons with further mixing of said flow of C₁-C₄ hydrocarbons with the flow of the raw material, characterized in that the olefin containing raw material is additionally mixed with the catalytic reforming gasoline fraction (boiling temperature max. 85 °C) that contains benzene, the olefins-to- benzene ratio in the final mixture is at leas 0.5 mole/mole, and said oligomerization reaction is performed under the conditions that provide for alkylation of at least part of said benzene.

2. Method according to p. 1 characterized in that the benzene containing fraction of refoirning gasoline is mixed with the raw material that contains, among other components, ethylene, the interaction of said raw material with said catalyst is performed in two reaction areas, and the reaction is performed in such a way that in one of the reaction areas the ethylene containing raw material interacts with the catalyst, the flow of reaction products obtained as a result of said interaction in the first reaction area is additionally mixed with the propylene and/or butylenes containing raw material, and the resultant mixture is supplied to the second reaction area, the mixture temperature at the input of the first reaction area being maintained higher than the mixture temperature at the input of the second reaction area.

3. Method according to p. 1 characterized in that the benzene containing fraction of reforming gasoline is mixed with the raw material that contains ethylene, the interaction of said raw material with said catalyst is performed in three reaction areas, and the reaction is performed in such a way that in one of the reaction areas the ethylene containing raw material interacts with the catalyst, the flow of reaction products obtained as a result of said interaction in the first reaction area is additionally mixed with the propylene containing raw material, the resultant mixture is supplied to the second reaction area, the flow of reaction products obtained as a result of the interaction in the second reaction area is additionally mixed with the raw material that contains butylenes, and the resultant mixture is supplied to the third reaction area, the mixture temperature at the input of the first reaction area being maintained higher than the mixture temperature at the input of the second reaction area.

4. Method according to p. 1 characterized in that the raw material is interacted with the catalyst in at least two parallel reaction areas with further mixing of the reaction products.

5. Method according to any of pp. 1 through 4 characterized in that the flow of reaction products obtained as a result of the process is additionally separated to obtain the benzene containing fraction of C₆ hydrocarbons with further complete or partial mixing of said fraction with the raw material in at least one of the reaction areas.

6. Method according to p. 5 characterized in that said benzene containing fraction of Cβ hydrocarbons is hydrated to selectively hydrate olefins before being mixed with the raw material.

7. Method according to any of pp. 1 through 6 characterized in that the raw materials before the supply to the heat exchangers are additionally mixed with hydrogen or a hydrogen containing gas wherein the content of hydrogen is at least 85 vol.%.

8. Device for obtaining high octane gasoline comprising eight heat exchangers, four reactors, two furnaces, two separators, two compressors, an air cooler, a water cooler, an ethane separation column, a stabilization column, a rectification column and a stripping column, wherein the first input of the first heat exchanger is connected to the ethylene containing fraction pipeline, the reforming gasoline fraction pipeline, and the pipeline of the part of the C₁-C₄ hydrocarbons flow obtained by vapof-liquid separation of the cooled product flow, the first input of said first heat exchanger is connected to the first input of the first furnace, the first output of which is connected to the input of the first reactor, the output of which is connected via a pipeline to the input of the second reactor, the output of which is connected via a pipeline to the input of the third reactor, the output of which is connected via a pipeline to the second input of the first heat exchanger and to the first inputs of the second and third heat exchangers, the second input of the second heat exchanger is connected to the propylene containing fraction pipeline and the pipeline of the recycled flow of the C1-C4 hydrocarbons flow separated from the product flow by vapor- hquid separation and rectification, the first output of the second heat exchanger is connected to the second input of said first furnace and via the second output of said first furnace and a pipeline to the pipeline that connects the output of the first reactor to the input of the second reactor, the second input of the third heat exchanger is connected to the butylenes containing fraction pipeline and the pipeline for the recycled flow of the C₁-C₄ hydrocarbons flow separated from the product flow by vapor-liquid separation and rectification, the first output of said third heat exchanger is connected to the third input of said first furnace and via the third output of said furnace and a pipeline to the pipeline that connects the output of the second reactor to the input of the third reactor, the second outputs of the first, second and third heat exchangers are connected to the input of the air cooler, the output of which is connected to the input of the water cooler, the output of which is connected to the input of the first separator, the first output of said first separator provides for the output of a balance amount of said recycled flow comprising part of the C₁-C₄ hydrocarbons flow and supply for mixing with the flow of C3-C₄ hydrocarbons supphed from the stabilization stage and to the ethylene containing raw material pipeline, the second output of said first separator is connected via the fourth heat exchanger to the first input of the ethane separation column, the first output of which is used for the removal of dry gas that is recycled, at least partially, via the second input back to the column, and the one partially removed from the plant, the second output of said ethane separation column provides for partial recycling of the unstable gasoline via the third input and for the supply of said unstable gasoline via the fifth heat exchanger and the first input to the stabilization column, the first output of said stabilization column provides for partial recycling of the mixture of C₃-C₄ hydrocarbons via the second input of the stabilization column, for mixing said mixture of hydrocarbons with the product effluent from said first separator and for obtaining an end product, i.e. the commercial propane-butane fraction, the second output of said stabilization column provides for connecting to the third input of said stabilization column and to the input of the sixth heat exchanger, the output of said sixth heat exchanger is connected to the first input of the rectification column, the first output of said rectification column provides for partial recycling of the main end product, i.e. nonaromatic C5-C6 hydrocarbons contained in gasoline, to said rectification column and for the uptake of said main product as an end product, the second output of said rectification column provides for the uptake of the benzene containing fraction as an end product and for connection to the hydration module that is implemented at the input of the seventh heat exchanger, directly upstream of which a second compressor is installed, the third output of said rectification column provides for partial recycling of the vat residue (Cγ₊ gasoline fraction hydrocarbons) to said rectification column and for the output of said vat residue as an end product, the first output of said seventh heat exchanger is connected to the input of the second separator, the first output of which is connected to the first input of the eighth heat exchanger and the second output of which is connected to the input of the second compressor, to which the hydrogen or hydrogen containing gas pipeline and the partial hydrogen containing gas removal pipeline are connected, the second output of said seventh heat exchanger is connected to the input of the second furnace, the output of which is connected to the input of the hydration module reactor, the output of which is connected to the second input of the seventh heat exchanger, the first output of said eighth heat exchanger is connected to the first input of the stripping column, the first output of which provides for connection to the second input of said stripping column and for output of the hydrogen containing gas dissolved in the liquid hydrogenate from the plant, the second output of said stripping column provides for partial recycling of the stable hydrated C₆ hydrocarbons fraction to said column and for partial supply of said hydrated Cβ hydrocarbons fraction to the second input of the eighth heat exchanger with further supply via the second output of the eighth heat exchanger for mixing with the ethylene containing raw material fraction.

9. Device according to p. 8 characterized in that an additional pipeline can be provided between the output of the first separator and the input of the first compressor for the supply of hydrogen or a hydrogen containing gas.

10. Device for obtaining high octane gasoline comprising six heat exchangers, three reactors, a furnace, an air cooler, a water cooler, a separator, a compressor, an ethane separation column, a stabilization column, a rectification column, wherein the first input of the first heat exchanger is connected to the ethylene containing fraction pipeline and the pipeline of the recycled part of the C1-C₄ hydrocarbons flow obtained by vapor-hquid separation of the cooled product flow, the first output of said first heat exchanger is connected to the first input of the furnace, the first output of which is connected to the input of the first reactor, the output of which is connected to the second input of said first heat exchanger, the second output of which is connected to the second input of an air cooler, the first input of said second heat exchanger is connected to the propylene containing fraction pipeline, the pipeline of the recycled part of the C₁-C₄ hydrocarbons flow obtained by vapor-hquid separation of the cooled product flow and the reforming gasoline fraction pipeline, the first output of said second heat exchanger is connected to the second input of the furnace, the second output of which is connected to the input of the second reactor, the output of which is connected to the second input of said second heat exchanger, the second output of which is connected to the input of the air cooler, the first input of the third heat exchanger is connected to the butylenes containing fraction pipeline, the pipeline of the recycled part of the C₁-C₄ hydrocarbons flow obtained by vapor-liquid separation of the cooled product flow and the reforming gasoline fraction pipeline, the first output of said third heat exchanger is connected to the third input of the furnace, the third output of which is connected to the input of the third reactor, the output of which is connected to the second input of die third heat exchanger, the second output of which is connected to the input of the air cooler, the output of which is connected to the input of a water cooler, the output of said water cooler is connected to the input of the separator, the first output of said separator provides for the removal of a balance amount of C₁-C₄ hydrocarbons flow and for mixing with the C3-C4 hydrocarbons and to the ethylene containing raw material pipeline, the second output of said separator is connected via the fourth heat exchanger to the first input of the ethane separation column, the first output of which is used for the removal of dry gas that is at least partially recycled via the second input back to the column and the one partially removed from the plant, the second output of said column provides for partial recycling of unstable gasoline via the third input back to the column and for the supply of said unstable gasoline via the fifth heat exchanger and the first input to the stabilization column, the first output of the stabilization column provides for the recycling of part of the mixture of C3-C₄ hydrocarbons vi the second input of the stabilization column, for mixing said mixture of hydrocarbons with the product effluent from said first compressor and for obtaining an end product, i.e. the commercial propane-butane fraction, the second output of said stabilization column provides for connecting to the third input of said stabilization column and to the input of the sixth heat exchanger, the output of said sixth heat exchanger is connected to the first input of the rectification column, the first output of said rectification column provides for partial recycling of the main end product, i.e. nonaromatic Cs-C₆ hydrocarbons contained in gasoline, to said rectification column and for the uptake of said main product as an end product, the second output of said rectification column provides for the uptake of the benzene containing fraction as an end product and for the supply of said benzene containing fraction to the ethylene, propylene and butylenes containing raw material pipelines, respectively, the third output of said rectification column provides for partial recycling of the vat residue to said rectification column and for the output of said vat residue as an end product, i.e. C7₊ gasoline fraction hydrocarbons.

11. Device according to p. 10 characterized in that an additional pipeline is provided between the first output of the separator and the input of the compressor for the supply of hydrogen or a hydrogen containing gas.