KR20160040641A - Integrated process for gasoline or aromatics production - Google Patents

Abstract

The present application provides a method for increasing the yield of hydrocarbon components from a hydrocarbon source to a gasoline blending pool. The method includes separating the naphtha source into components in the first stream that are more easily processed in the decomposition unit and components of the second stream that are more easily processed in the reforming unit. The method includes the ability to convert the components from the decomposition stream to the reforming stream.

Description

[0001] INTEGRATED PROCESS FOR GASOLINE OR AROMATICS PRODUCTION [0002]

Priority claim

This application claims priority from U.S. Patent Application No. 14 / 260,784, filed April 24, 2014, which claims the benefit of U.S. Provisional Patent Application No. 61 / 863,025, filed August 7, 2013, Quot; are hereby incorporated by reference in their entirety.

Technical field

The present invention relates to a method and system for producing aromatics from heavy hydrocarbon streams. In particular, the process increases the yield and flexibility of the production of aromatic compounds and light olefins from hydrocarbon sources.

Reforming of petroleum raw materials is an important method for producing useful products. One important method is the separation and up-grading of hydrocarbons for motor fuels, such as the production of naphtha feed streams in gasoline production and octane upgrading of naphtha. However, the hydrocarbon feed stream from the raw oil source includes the production of chemical precursors useful for use in the manufacture of plastics, detergents and other products.

Upgrading of gasoline is an important process, and an improvement on the conversion of the naphtha feed stream to increase octane number is disclosed in U.S. Patent Nos. 3,729,409; 3,753,891; 3,767,568; 4,839,024; 4,882,040; And 5,242,576. The processes include various means for enhancing the octane number, particularly means for enhancing the aromatics content of gasoline.

The processes include operating a few different catalysts, such as a single metal catalyst for lower boiling hydrocarbons or a non-acid catalyst and a dual metal catalyst for higher boiling hydrocarbons, as opposed to separating the source. Other improvements are described in U.S. Patent Nos. 4,677,094; 6,809,061; And 7,799, 729, all of which are incorporated herein by reference. However, there are limitations to the methods and catalysts presented in the above patent documents, which can involve a significant increase in cost.

Light olefins have traditionally been produced through vapor or catalytic cracking processes and include ethylene and propylene. Light olefins are also derived from the same sources as gasoline. Due to limited availability and high cost of petroleum sources, the cost of producing light olefins from such petroleum sources has continued to increase. The ability to shift components in a source for light olefins and gasoline pools allows the producer to economically select the most important product series and to shift some of the hydrocarbon components in an efficient manner .

A method for improving the gasoline yield is presented. A first embodiment of the present invention is a process for converting a treated hydrocarbon feed stream comprising: transferring a treated hydrocarbon feed stream to a separation unit to produce a normal paraffin-rich extract stream and a reduced normal hydrocarbon content raffinate stream ; The extract stream is transferred to an extract separation system to produce an extract overhead stream comprising nC5 and nC6 compounds, an extract intermediate stream comprising nC7 to nC11 compounds, and an extract bottom stream comprising a desorbent ; Transferring the raffinate stream to a raffinate separation system to form a raffinate overhead stream comprising iC5 and iC6 compounds, an intermediate raffinate stream comprising non-hydrocarbon and aromatic compounds in the C6 to C11 carbon range, Generating a raffinate floor stream; And transferring the intermediate raffinate stream to a reforming unit to produce an aromatic stream. One embodiment of the present invention is directed to a process for the separation of hydrocarbons from hydrocarbons by feeding a hydrocarbon feed stream to a fractionation unit to produce an overhead stream comprising C4 and lighter hydrocarbons and a bottoms stream comprising C5 + hydrocarbons, Lt; / RTI > hydrogenation stream; And transferring the treated hydrogenation stream to a separate unit, from any of the previous embodiments of this paragraph to the first embodiment of this paragraph, any or all of the foregoing. One embodiment of the present invention is directed to a method of generating an isomerization stream comprising the steps of: transferring a portion of an extract overhead stream to a isomerization unit to produce an isomerization stream comprising C5 and C6 compounds; Any or all of the first embodiment of the paragraph. One embodiment of the present invention is any, any, or all of the previous embodiments of this paragraph to the first embodiment of this paragraph, further comprising transferring the isomerization stream to a separation unit.

A second embodiment of the present invention is a method of converting a naphtha feed stream comprising fractionating a naphtha feed stream to produce a naphtha overhead stream comprising C4 and lighter hydrocarbons and a naphtha bottom stream comprising C5 + ; Hydrotreating the naphtha bottoms stream to produce acetylene, diolefin, sulfur and reduced nitrogen content hydrogenation streams; Transferring the hydrogenation stream to a separation unit to produce a normal hydrocarbons extracult stream and a raffinate stream; Transporting the extract stream to an extractive separation system to produce an extractor bottom stream comprising an extract overhead stream comprising nC5 and nC6 compounds, an extract intermediate stream comprising nC7 to nC11 compounds, and a desorbent, ; Transferring the raffinate stream to a raffinate separation system to produce a raffinate overhead comprising an iC5 and iC6 compound, an intermediate raffinate stream comprising a C6 to C11 aromatic compound and a non-hydrocarbon, and a raffinate stream comprising a desorbent, ; Transferring the intermediate extract stream and the naphtha overhead stream to a naphtha cracking unit to produce light olefins; And transferring the intermediate raffinate stream to a reforming unit to produce an aromatic stream. One embodiment of the present invention is directed to a method of generating an isomerization stream comprising the steps of: transferring a portion of an extract overhead stream to a isomerization unit to produce an isomerization stream comprising C5 and C6 compounds; Any or all of the second embodiment of the paragraph. One embodiment of the present invention is any, any, or all of the preceding embodiments of this paragraph to the second embodiment of this paragraph, further comprising the step of transferring the isomerization stream to a separation unit.

Other objects, advantages and applications of the present invention will become apparent to those skilled in the art from the following detailed description and drawings in order to practice the invention.

1 is a flow chart of the method;
Figure 2 is a specific embodiment of the method.

This embodiment provides for efficient use of a hydrocarbon source. The production of valuable high value products from low value hydrocarbon sources is critical to the economics of petroleum processing plants. The flexibility in manufacturing high value products is desirable in meeting the changing needs in different product lines.

This embodiment provides flexibility in the processing of hydrocarbon feed streams for the production of light olefins and / or aromatics. As shown in FIG. 1, the method includes transferring the treated hydrocarbon stream 8 to a separation unit 10. The separation unit 10 produces an extract stream 12 rich in normal hydrocarbons and a raffinate stream 14 with a reduced normal hydrocarbon content. The extract stream 12 is sent to an extract separation system 20 to produce an extract overhead stream 22. The extract separation system 20 may also generate an extract intermediate stream 24 and an extract bottom stream 26.

The normal component in the hydrocarbon stream is more readily decomposed than the non-terminal component to produce light olefins. The normal component is also less likely to be modified into an aromatic compound than the non-terminal component. The transfer of the different streams to the appropriate downstream processing unit and the separation of the combined normal and non-nonomical components improves the flexibility and economics of decomposition and modification of the naphtha. The ability to convert the normal component to the non-terminal component makes it possible to shift the hydrocarbon component from the stream fed to the cracking unit to the stream for producing the gasoline component.

Extracted overhead stream 22 may contain normal C5 and C6 compounds and extrast intermediate stream 24 may contain normal C7 and heavier compounds and extracontinental bottoms stream 26 may be separated And may include a recycle stream re-delivered to the unit 10. Extract intermediate stream 24 is transferred to decomposition unit 40 to produce light olefins. In one embodiment, the decomposition unit 40 is a naphtha steam cracking unit.

In one embodiment, the separation unit 10 is an adsorptive separation unit and the recycle stream 26 is desorbent recycle from the extract separation system 20 to the separation unit 10. The extract separation system 20 may include one or more fractionation columns for separating the extract stream from the desorbent. The extract separation system 20 may also separate the extract stream 12 into a plurality of streams. Options for the separation process include separation wall columns, or other means for separating the hydrocarbon stream.

The raffinate stream 14 is transferred to a raffinate separation system 30 to produce raffinate overhead stream 32, intermediate raffinate stream 34 and raffinate bottom stream 36. The raffinate overhead stream 32 may comprise isopentane and isohexane, the intermediate raffinate stream 34 comprises non-hydrocarbon hydrocarbons ranging from C6 to C11, naphthene, and aromatics, Stream 36 includes a recycle stream back to separation unit 10.

In the adsorption separation system 10, raffinate recycle is a desorbent used in the adsorption separation process. The intermediate raffinate stream 34 is transferred to the reforming unit 50 to produce a reformate stream 52 comprising an aromatic compound.

In certain embodiments, as shown in Figure 2, the process processes the naphtha feed stream. The naphtha feed stream comprises a plurality of hydrocarbon components and is primarily transported to the decomposition unit for the production of light olefins. However, the composition of the naphtha stream includes components that are not well decomposed into light olefins, which causes further processing. The naphtha feed stream also contains hydrocarbons useful for conversion to aromatics. This embodiment seeks to separate the naphtha feed stream to increase the yield and efficiency of the naphtha cracking unit and the reforming unit. The naphtha feed stream 76 is transferred to a fractionation unit 70 to produce an overhead stream 72 comprising C4 and lighter hydrocarbons and a bottoms stream 74 comprising C5 and higher order hydrocarbons. The overhead stream 72 is transferred to the decomposition unit 40 to produce a light olefin product stream 42.

The naphtha feed stream may typically comprise hydrocarbons in the C4 to C11 range. Thus, the adsorptive separation unit 10 will use a suitable desorbent, which is usually outside this range. One of the desorbents acting on the light naphtha having components in the C4 to C11 range is n-C12.

The naphtha bottoms stream 74 is transferred to the hydrotreating unit 80 to produce the treated hydrocarbon stream 8. Hydrotreating the naphtha bottoms stream 74 removes sulfur impurities and nitrogen impurities. The hydrotreating can also perform some hydrogenation of the reactive components, such as acetylene and diolefins. The hydrotreated or hydrogenated stream 8 is transferred to an adsorptive separation unit 10 to produce an extract stream 12 and a raffinate stream 14. The adsorbent in the adsorbing separation unit 10 is selected so as to separate normal hydrocarbons, particularly normal paraffins, from non-hydrocarbon hydrocarbons. The extract stream 12 contains normal hydrocarbons and the raffinate stream 14 contains both non-aromatic and aromatic hydrocarbons.

The raffinate stream 14 is conveyed to the raffinate separation system 30. The raffinate separation system 30 generates the raffinate overhead stream 32, the intermediate raffinate stream 34, and the raffinate bottom stream 36. The raffinate separation system 30 may include two fractionation columns, separation wall columns, or other means for separating the mixture into two or three streams. Fractionation is preferred because the components in the raffinate stream are easily separated due to their non-point difference. The adsorptive separation system 10 uses a desorbent and the raffinate bottoms stream 36 contains a desorbent that is recycled to the adsorptive separation system 10. The raffinate overhead stream contains iC5 and iC6 compounds and can be used for downstream processing, including addition to gasoline blending pulps. The intermediate raffinate stream 34 containing aromatic compounds and non-hydrocarbon hydrocarbons having higher boiling points than the iC5 or iC6 compounds is delivered to the reforming unit 50 to produce a reforming oil 52 having an increased aromatics content.

The extract stream 12 is conveyed to an extract separation system 20 to produce an extract overhead stream 22, an extract intermediate stream 24, and an extract bottom stream 26. The extract separation system 20 may include a plurality of fractionation columns, and the preferred system uses a separation wall column. Extract bottom stream 26 comprises a desorbent recycled to separation unit 10. Extract intermediate stream 24 is transferred to decomposition unit 40 to convert normal paraffin to light olefin 42. A typical decomposition unit is a naphtha steam cracking unit, but may also include a catalytic cracking unit. The extract overhead stream 22 may also be transported to the decomposition unit 40, but, in the alternative, the extract overhead stream may be transported to the isomerization unit 60.

The isomerization unit 60 converts the overhead stream 22 having normal C5 and C6 paraffins into an isomerization stream 62 having a mixture of normal and iso-C5 and C6 paraffins. The isomerization stream 62 is conveyed to the separation unit 10 where the non-terminal components of the isomerization stream 62 are removed from the raffinate stream 14. [ This allows more hydrocarbons to be delivered to the reforming unit 50 to increase the reforming oil 52 or to the raffinate overhead stream 32 for downstream processing and to be delivered to the reforming unit 50 As an option.

One preferred embodiment relates to integrating the separation system, isomerization system, and contact reforming into an integrated refining-petroleum operation. The process provides hydrocarbon shifts between a cracking process to produce light olefins and a reforming process to produce aromatic compounds. The flexibility of the plant to produce the desired product stream is thus provided.

In one preferred embodiment, an extract separation system, or a raffinate separation system, can produce three separate streams using a separation wall column. This can save money and operating costs. This method will allow for flexibility in the gasoline manufacturing sector either through shifting of the hydrocarbon components in the naphtha feed stream, in particular from the cracked streams of the C5 and C6 components, to the reformate stream, or directly to the gasoline blending pool.

It is to be understood that the invention is not to be limited to the disclosed embodiments but is intended to cover various modifications and equivalent arrangements included within the scope of the appended claims .

Claims (10)

A method for converting a treated hydrocarbon feed stream,
Transferring the treated hydrocarbon feed stream to a separation unit to produce a normal paraffin-rich extract stream and a reduced normal hydrocarbon content raffinate stream;
The extract stream is transferred to an extract separation system to produce an extract overhead stream comprising nC5 and nC6 compounds, an extract intermediate stream comprising nC7 to nC11 compounds, and an extract bottom stream comprising a desorbent ;
The raffinate stream is transferred to a raffinate separation system to produce a raffinate overhead stream comprising iC5 and iC6 compounds, an intermediate raffinate stream comprising aromatic and non-hydrocarbon hydrocarbons, and a raffinate bottom stream comprising desorbent ; And
Transferring the intermediate raffinate stream to a reforming unit to produce an aromatic stream
≪ / RTI > The method according to claim 1,
Transferring the hydrocarbon feed stream to a fractionation unit to produce an overhead stream comprising C4 and lighter hydrocarbons and a bottoms stream comprising C5 + hydrocarbons;
Hydrotreating the bottoms stream to produce a treated hydrogenation stream; And
Transferring the treated hydrogenation stream to a separation unit
≪ / RTI > 3. The method of claim 2, further comprising transferring the overhead stream to an decomposition unit. 2. The method of claim 1, further comprising the step of transporting an extract intermediate stream to a decomposition unit. The method of claim 1, further comprising transferring a portion of the extract overhead stream to a isomerization unit to produce an isomerization stream comprising C5 and C6 compounds. 6. The method of claim 5, further comprising transferring the isomerization stream to a separation unit. 2. The method of claim 1, further comprising the step of transferring a portion of the export overhead stream to a decomposition unit. 8. The method of claim 7, wherein the hydrocarbon feed stream is a naphtha feed stream. The conversion method according to claim 7, wherein the decomposition unit is a naphtha decomposition unit. The method of claim 1, further comprising transferring the raffinate overhead stream to a gasoline blending pool.

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