TW201508057A - Naphtha cracking - Google Patents

Abstract

A process for increasing the yields of light olefins and the yields of aromatics from a hydrocarbon stream is presented. The process includes a first separation to direct the light components that are not reformable to a cracking unit, with the remainder passed to a second separation unit. The second separation unit extracts normal components from the hydrocarbon stream to pass to the cracking unit. The resulting hydrocarbon stream with reduced light ends and reduced normals is passed to a reforming unit.

Description

Naphtha cracking Statement of priority

U.S. Provisional Application Nos. 61/830,964 and 61/830,981, both to the U.S. Application Serial No. 14/271,392, filed on May 6, 2014 Interest of 14/271, 399.

This invention relates to a process for producing light olefins from a naphtha feed stream. The present invention is also directed to an improved method of increasing the yield of light olefins.

Ethylene and propylene, light olefins having two or three atoms per molecule are important chemicals for the production of other suitable materials such as polyethylene and polypropylene, respectively. Polyethylene and polypropylene are the two most common plastics used today and are used as a manufacturing material and as a packaging material. Other uses of ethylene and propylene include the production of vinyl chloride, ethylene oxide, ethylbenzene and ethanol. Steam cracking or hydrocarbon pyrolysis produces substantially all of ethylene and propylene. Hydrocarbons used as feedstocks for the production of light olefins include natural gas, petroleum liquids, and carbonaceous materials (including coal, recycled plastic, or any organic material).

Ethylene equipment is an extremely complex combination of reaction and gas recovery systems. The feed is fed to the cracking zone in the presence of steam under effective heat conditions to produce a gas mixture of pyrolyzed reactor effluent. The gas mixture of the pyrolyzed reactor effluent is stabilized and separated into purified components via a series of low temperature and conventional fractionation steps. a typical ethylene separation portion of an ethylene plant (containing a low temperature and a conventional fractionation step to recover an ethylene product having The purity of more than 99.5% ethylene is described in an article by V. Kaiser and M. Picciotti, entitled "Better Ethylene Separation Device." This article was published in November 1988 by HYDROCARBON PROCESSING MAGAZINE In pages 57 to 61 and incorporated herein by reference.

Known methods are used to increase the conversion of the ethylene product fraction produced from the zeolite cracking process to produce more ethylene and propylene by disproportionation or metathesis of the olefin. Such process is disclosed in U.S. Patent No. 5,026,935 and No. 5,026,936, wherein the metathesis reaction employed in combination with a catalytic cracking step to step by the metathesis of C ₄ and heavier molecules to produce more ethylene and propylene. The catalytic cracking step employs a zeolite catalyst to convert a hydrocarbon stream having 4 or more carbon atoms per molecule to produce an olefin having fewer carbon atoms per molecule. The hydrocarbon feed stream of the zeolite catalyst typically contains from 40% to 95% by weight of an alkane (having 4 or more carbon atoms per molecule) and from 5% to 60% by weight of an olefin (having 4 or more carbon atoms per molecule) )mixture. In U.S. Patent No. 5,043,522, the preferred catalyst for use in such zeolite cracking processes is acid zeolite, examples of which include several ZSM-type zeolites or borosilicates. Among the ZSM type zeolites, ZSM-5 is preferred. This U.S. patent discloses that other zeolite-containing materials that can be used in the cracking process to produce ethylene and propylene include zeolite A, zeolite X, zeolite Y, zeolite ZK-5, zeolite ZK-4, synthetic mordenite, de-alud mordenite, and natural Zeolites present (including chabazite, faujasite, mordenite, and the like). A zeolite which is ion exchanged to replace the alkali metal present in the zeolite is preferred. Preferred cations for exchanging cations are hydrogen, ammonium, rare earth metals, and mixtures thereof.

European Patent No. 109,059 B1 discloses a process by which a feed stream (containing an olefin having 4 to 12 carbon atoms per molecule) and ZSM-5 or ZSM-11 zeolite (having less than or equal to 300 cerium oxide to alumina) Atomic ratio) A method of contacting the feed stream to propylene at a temperature of from 400 ° C to 600 ° C. The ZSM-5 or ZSM-11 zeolite is exchanged with hydrogen or ammonium cations. This reference also discloses that although the conversion of any olefin having less than 4 carbon atoms per molecule to propylene is recovered, unreacted alkane tends to accumulate in the recovery stream. This reference provides an additional oligomerization step wherein the olefins having 4 carbon atoms oligomer to assist in removing difficult by conventional fractionation C ₄ olefins from paraffins separated, and in particular words such as butane, isobutane . In a related European patent 109060 B1, a process for converting butene to propylene is disclosed. The method comprises contacting butene with a zeolitic compound selected from the group consisting of sillimanite, borax, colored sillimanite and their zeolites ZSM-5 and ZSM-11 (wherein cerium oxide is more than alumina A group consisting of greater than or equal to 350). The conversion of pure zeolite compound per kg of butene is carried out at a temperature of from 500 ° C to 600 ° C and at a space velocity of from 5 kg / h to 200 kg / h. European Patent No. 109060B1 discloses the use of sillimanite-1 in the form of ion exchange, impregnation or coprecipitation having a modified element selected from the group consisting of chromium, magnesium, calcium, strontium and barium.

In general, heavier olefins having six or more carbon atoms per molecule (produced in commercially available ethylene equipment) are suitable for the production of aromatic hydrocarbons. The portion of the olefin product includes an olefin having four carbon atoms per molecule. This section includes monoolefins and dienes and certain alkanes, including butane and isobutane. Since the fraction of four carbon atoms per molecule is generally of lower value and requires considerable processing to separate the diolefin from the monoolefin, methods are sought to improve the utilization of this portion of the ethylene plant product and increase the total ethylene and propylene production. .

It is difficult to obtain a high selectivity of ethylene and propylene in naphtha cracking while maintaining high conversion. Improvements in catalysts and methods are therefore needed to achieve this goal.

The present invention provides a process for optimizing the yield of light olefins and aromatics and increasing the yield. The method includes delivering a hydrocarbon stream to a first separation unit to generate a first light stream and a first heavy stream. The first light stream consists of a hydrocarbon component which is a light fraction and which is not easily recombined, but can be easily cracked in a cracking reactor to produce a light olefin. The first heavy stream is passed to a hydrotreating unit to remove residual sulfur compounds and nitrogen compounds and to produce a treated heavy stream. The heavy stream is passed to a second separation unit to produce an extract stream comprising linear hydrocarbons from the heavy hydrocarbon stream. Separation device A raffinate stream comprising non-linear components of a heavy hydrocarbon stream. The method further includes conveying the first light stream and the extract stream to a cracking unit to produce a light olefin product stream. The method includes delivering a raffinate stream to a recombination unit to produce a recombinant treatment stream comprising an aromatic.

The cracking unit can be a steam cracker, or a catalytic naphtha cracker, wherein the hydrocarbon stream comprises straight run naphtha. In one embodiment, the first light stream comprises a C5 hydrocarbon and some C6 hydrocarbons. The fraction of the first separation column comprises conveying hexane, methylcyclopentane, methylpentane and dimethylbutane in the first light stream.

Other objects, advantages and applications of the present invention will become apparent to those skilled in the <RTIgt;

6‧‧‧Second hydrocarbon stream

8‧‧‧ hydrocarbon feed stream / straight run naphtha feed stream

10‧‧‧First separation tower/naphtha splitter

12‧‧‧First Light Stream / Top Flow

14‧‧‧First Heavy Stream/Heavy Bottom Residue Logistics

20‧‧‧Hydrogenation unit

22‧‧‧Processed heavy flow

30‧‧‧Second separation device

32‧‧‧First extraction stream

34‧‧‧Rust logistics

40‧‧‧Cleaning device

50‧‧‧Reorganization device

52‧‧‧Processing flow

Figure 1 is a flow diagram of a process for increasing the yield of light olefins obtained from a naphtha cracker.

The production of light olefins is produced by the use of a cracking unit to crack heavier hydrocarbons. A cracking unit is designed for the target flow rate to convert the hydrocarbon feed stream. The yield can be changed or increased by controlling the feed stream replenishment or its content. By manipulating the feed stream content, the production of the cracker can be increased. In addition, in converting the non-aromatic component to the aromatic component, the yield of the aromatics for the aromatic complex feed can also be increased by replenishing the feed stream of the reforming unit. The method of the present invention is directed to optimally operating the cracking unit and the reforming unit wherein the feed to each unit remains substantially constant. In one embodiment, the method utilizes a straight run naphtha feed stream to be split and to be delivered to both units. As used hereinafter, the straight run naphtha feed stream is intended to include a full boiling range naphtha feed stream. This process is used to convert relatively low value naphtha feed streams to higher value products such as light olefins and aromatics.

The present invention is directed to optimizing the yield of two processing units (the cracking unit and the catalytic recombining unit), and the method can also be used to increase the yield of each individual unit. The hydrocarbon stream contains a mixture of the miscellaneous. The first separation process typically proceeds around the boiling point where a fraction is made in the boiling range. Other separation methods are also used downstream to extract specific classes of hydrocarbons.

More complex separations of hydrocarbon streams have been found to increase the throughput of downstream processing units while maintaining a substantially constant flow rate of subsequent processing units. A typical feed stream for the cracking unit and the reforming unit is a straight run naphtha feed stream. It is contemplated, however, that other feed streams can be used in this process, and as used herein, the term naphtha feed stream is intended to encompass other potential hydrocarbon feed streams that can be used for cracking and recombination.

In one embodiment of the method, the naphtha feed stream is passed to a cracking unit to produce a light olefin. As shown in FIG. 1, the process for producing light olefins includes passing a hydrocarbon feed stream 8 to a first separation column 10. The separation column 10 generates a first light stream 12 and a first heavy stream 14. The first heavy stream 14 is passed to a hydrotreating unit 20 to produce a treated heavy stream 22. The treated heavy stream 22 is passed to a second separation unit 30 to generate a first extraction stream 32 and a raffinate stream 34. The first extract stream 32 comprises a linear hydrocarbon and the raffinate stream 34 comprises a non-linear hydrocarbon. The first extract stream 32 and the first light stream 12 are passed to a cracking unit 40 to produce a light olefin. The cracking unit 40 can be a steam cracker or a catalytic naphtha cracking unit.

The first light stream 12 can comprise C5 hydrocarbons and is a separator of light hydrocarbons from a straight run naphtha stream. It has been found that C6 compounds such as methylcyclopentane are more difficult to recombine, and thus it has been found to be advantageous to transfer the first separation column 10 (i.e., to deliver certain C6 compounds (including methylcyclopentane) and overhead stream 12). Heavy stream 14 can comprise C7 and heavier components, as well as certain readily recombinable C6 components, such as cyclohexane.

The second separation device 30 is preferably an adsorption separation device, and the separation is controlled by selecting an adsorbent and a desorbent. For the present method, a second separation unit 30 is designed for separating linear hydrocarbons in the C5 to C11 range from the treated heavy stream 22. The linear hydrocarbons are separated and passed to an extract stream 32 with a raffinate stream 34 comprising non-linear hydrocarbons. The desorbent for the preferred process is a linear C12 alkane.

The raffinate stream 34 can be passed to the recombination unit 50 to produce a treatment stream 52 comprising aromatics. Process stream 52 can be passed to the aromatic complex to convert to higher value production Things.

In one embodiment, the method includes increasing the yield of aromatics obtained from the autocatalytic recombination unit 50. The method can include conveying a heavy stream generated from other processing devices, such as a heavy cracking stream, wherein the heavy cracking stream comprises C7 and heavier hydrocarbons and the heavy cracking stream is passed to the recombination unit 50. The recombination unit is preferably a continuous catalytic recombination unit in which the catalyst is in a moving bed and the catalyst is circulated through the reactor to the regenerator to regenerate the catalyst. This method provides a continuous process.

In a method of increasing the yield of aromatics obtained from recombination unit 50, the method includes maintaining a substantially constant flow rate while varying the feed composition to increase aromatics production. The method includes delivering a straight run naphtha feed stream 8 to a naphtha splitter 10 to produce a heavy bottoms residual stream 14. The heavy bottoms residual stream 14 is passed to a hydrotreating unit 20 to produce a treated heavy stream 22. The treated heavy stream 22 is passed to an adsorptive separation unit 30 to separate linear hydrocarbons from the treated heavy stream 22. The linear hydrocarbons are passed to the extract stream 32, and the adsorptive separation unit 30 produces a raffinate stream 34 comprising non-linear hydrocarbons. The raffinate stream 34 is passed to a catalytic recombination unit 50. Non-linear hydrocarbons are more readily reconstituted than aromatic hydrocarbons, and changing the feed composition of recombination unit 50 increases aromatics production without increasing feed flow rate.

The process utilizes an adsorptive separation process to separate a hydrocarbon feed stream that is split and passed to a cracking unit and a reconstitution unit. A typical feed stream is a naphtha feed stream and the performance of the cracker and catalytic recombination unit is improved. The adsorptive separation unit separates the linear alkane from the non-linear alkane. Non-linear components include branched paraffins, naphthenes, and aromatics. The method preferably utilizes a naphtha splitter to separate light components including the C5-component in naphtha. The C5-component is removed prior to delivery of the naphtha to the recombiner because the C5-component cannot be converted to an aromatic.

Straight-run naphtha and lighter component hydrocarbons can be fed to the naphtha stripper to aid in stripping the C5-component naphtha. Hydrotreated straight run naphtha and can be subsequently transferred To the reorganization device. Hydrotreating removes sulfur and other impurities that can act as inhibitors of the catalyst in subsequent processing units.

One aspect of this method is to alter the distribution of hydrocarbons fed to the cracking unit and the reforming unit. Changing the feed distribution enhances the performance of the cracker and the reconstitution device. Instead of performing standard operations for splitting naphtha into C5-, an improvement is made to adjust the splitter such that the top stream of the naphtha splitter 10 includes additional components that are difficult to recombine. Additional components in the overhead stream include dimethylbutane, methylpentane, linear hexane, and methylcyclopentane (MCP). These additional components are transferred to the cracking unit 40. By removing these components from the heavy bottoms residual stream, subsequent streams that are passed to the recombination unit enhance aromatic yield.

Another aspect of this method is the additional separation of the heavy bottoms residual stream. Additional components that are also more difficult to recombine but are more susceptible to cracking into light olefins include heavier linear alkanes. The adsorptive separation system allows the separation of linear alkanes that are not easily separated by fractional distillation. The linear component is then transferred to the cracking unit and the non-linear component is delivered to the reconstitution unit.

One aspect of the method is to optimize the yield of the cracking unit and the reconstituting unit. The cracking unit and the recombining unit can be designed and sized for a predetermined flow of naphtha feed stream. The addition of a naphtha splitter and an adsorptive separation device allows the feed composition to be transferred to the cracking unit and the reconstitution unit while maintaining a substantially constant flow rate to the two units.

In one embodiment, a method for optimizing the production of downstream operations in the production of light olefins and aromatics includes optimal production of aromatics and light olefins by selective separation of hydrocarbon components from the hydrocarbon stream. Method. The method includes delivering a first hydrocarbon stream 8 to a first separation column 10 to generate a first light stream 12 and a first heavy stream 14. The first heavy stream 14 is passed to a hydrotreating unit 20 to produce a treated heavy stream 22. The treated heavy stream 22 is passed to a second separation unit 30 to produce an extract stream 32 and a raffinate stream 34. The extract stream 32 and the first light stream 12 are passed to a cracking unit 40. In order to maintain a constant flow rate to the cracker 40, the extract stream 32 and the first light stream 12 are passed to a second one of the crackers 40. Hydrocarbon stream 6 is added. The raffinate stream 34 is passed to a catalytic recombination unit 50 to produce a process stream 52 having an increased aromatic content.

A typical hydrocarbon stream for cracking is a naphtha stream, and the first hydrocarbon stream and the second hydrocarbon stream may be straight run naphtha, and the stream may be formed by splitting straight run naphtha. In one embodiment, the second hydrocarbon stream can be a light naphtha stream that can be produced during the production of the naphtha stream. The treatment and flow rate are adjusted to maintain a substantially constant flow rate to the cracking unit and the catalytic recombination unit. This control is assisted by splitting the first and second hydrocarbon streams, wherein the amount of the first light stream 12 generated by the first separation column 10 and the amount of the extract stream 32 generated by the second separation unit 30 are reduced. Or adding a second hydrocarbon stream 6.

The method may further comprise an upstream separation device to obtain straight run naphtha and perform a process of splitting the light naphtha stream with the residual naphtha stream.

The raffinate stream is passed to a catalytic recombination unit wherein the linear alkane in the raffinate stream has been removed. The raffinate stream can be used as a downstream blending stream for gasoline or other products. Preferably, the raffinate stream is passed to a catalytic recombination unit to increase the yield of the aromatics while the recombination unit product stream is passed to the aromatic complex.

The optimization method generates a first light stream from the first separation column 10. The first light stream comprises the C5-component from the naphtha stream because the C5-components do not readily reconstitute the aromatics. It has also been discovered that the first separation column 10 is operated to deliver certain C6 components and a light overhead stream 12. These components include methylcyclopentane (MCP), linear hexane, methylpentane, and dimethylbutane. For the process of cracking to form a heavy cracking stream in which the components have a large amount of C7 hydrocarbons, the heavy cracking stream can be passed to a recombination unit.

An example is used to illustrate the improvements that can be achieved via this method.

Simulation result table

The simulation is based on information from the operation of the device. The protocol employs a 1370 KMTA constant straight run (SR) naphtha feed from a cracking unit. The SR naphtha is split and maintains a constant flow rate of the cracking unit while reducing the SR naphtha content delivered to the cracking unit, while the light ends from the first separation column are increased and the extract from the second separation unit is increased. The residue is introduced into a catalytic recombination unit.

It can be seen from the results that the light olefin production is significantly increased in the basic case and is even greater by the second separation device. Also, as can be seen from the aromatics production, the addition of a second separation unit increases the amount of hydrocarbons converted to aromatics. Furthermore, the results show that in order to maintain a constant RONC (research octane number) of the aromatics generated by the recombination device, the content of the catalyst can be reduced, thereby saving a large amount of resources and operating costs.

While the present invention has been described with respect to the preferred embodiments of the present invention, it is understood that the invention is not limited to the disclosed embodiments, but is intended to cover various modifications and equivalent arrangements within the scope of the appended claims. .

Specific embodiment

While the following is described in conjunction with the specific embodiments, it is understood that this description is intended to be illustrative and not restrict

A first embodiment of the invention is a process for optimizing the production of downstream operations in the production of light olefins and aromatics, the method comprising delivering a first hydrocarbon stream to a first separation column to produce a first light a mass flow and a first heavy stream; transferring the first heavy stream to a hydrotreating unit to produce a processed heavy stream; transferring the treated heavy stream to a second separating unit to generate an extract stream a raffinate stream; the extract stream, the first light stream, and the second hydrocarbon stream are passed to a cracking unit; and the raffinate stream is passed to a catalytic recombination unit. An embodiment of the present invention is one, any or all of the first embodiment of the present paragraph to the first embodiment of the paragraph, wherein the first hydrocarbon stream is a straight run naphtha stream. An embodiment of the present invention is this paragraph A previous embodiment to any, all or all of the first embodiment of the paragraph wherein the second hydrocarbon stream is a light naphtha or a straight run. An embodiment of the present invention is one, any or all of the first embodiment of the present paragraph to the first embodiment of the paragraph wherein the total flow delivered to the cracking unit is maintained constant. An embodiment of the present invention is one, any or all of the first embodiment of the present paragraph to the first embodiment of the paragraph, further comprising splitting the straight run naphtha stream into the first hydrocarbon stream and the first Dihydrocarbon stream.

A second embodiment of the present invention is a method of optimizing a hydrocarbon stream composition to improve the performance of downstream operations, the method comprising delivering a hydrocarbon stream to a first separation column to generate a first light stream and a first heavy stream; Transferring the first heavy stream to a hydrotreating unit to produce a treated heavy stream; passing the treated heavy stream to a second separating unit to generate a first extract stream comprising linear hydrocarbons a raffinate stream of linear hydrocarbons; and delivering the first light stream and the first extract stream to a cracking unit to produce light olefins. An embodiment of the present invention is one, any or all of the previous embodiments of the present paragraph to the second embodiment of the paragraph, further comprising transferring the raffinate stream to the catalytic recombination unit. An embodiment of the present invention is one, any or all of the preceding embodiments of the present paragraph to the second embodiment of the paragraph wherein the first light stream comprises C5 hydrocarbons. An embodiment of the invention is one, any or all of the preceding embodiments to the second embodiment of the paragraph, wherein the first light stream comprises methylcyclopentane and a lighter hydrocarbon . An embodiment of the invention is one, any or all of the embodiments of the preceding paragraphs to the second embodiment of the paragraph wherein the first light stream comprises cyclohexane and a lighter weight product. An embodiment of the present invention is one, any or all of the second embodiment of the present paragraph to the second embodiment of the present paragraph, wherein the cracking device generates a cracker residual stream and further comprising transferring the cracker residual stream To the reorganization device. An embodiment of the invention is one, any or all of the embodiments of the preceding paragraphs to the second embodiment of the paragraph wherein the hydrocarbon stream is a cracked naphtha stream. An embodiment of the invention is one, any or all of the embodiments of the previous embodiment to the second embodiment of the paragraph, wherein the second separating device is an adsorptive separation device.

A third embodiment of the invention is a method of increasing the aromatics content of a recombination stream, the method comprising conveying a hydrocarbon stream to a splitter column to produce a top stream comprising light hydrocarbons and a bottoms stream comprising heavy hydrocarbons Transferring the bottom residual stream to a hydrotreating unit to produce a treated heavy stream; passing the treated heavy stream to a separation unit to produce an extract stream comprising linear hydrocarbons and a non-linear hydrocarbon And leaving the raffinate stream to a catalytic recombination unit to produce a process stream having an increased aromatic content. An embodiment of the present invention is one, any or all of the third embodiment of the present paragraph to the third embodiment, wherein the splitter tower is a naphtha splitter tower and the top stream comprises C6 and Lighter hydrocarbons, and the bottoms residual stream contains C7 and heavier hydrocarbons. An embodiment of the present invention is one, any or all of the third embodiment of the present paragraph to the third embodiment of the paragraph, further comprising conveying the overhead stream to the cracking unit. An embodiment of the present invention is one, any or all of the third embodiment of the present paragraph to the third embodiment of the paragraph, further comprising splitting the naphtha feed stream into the first portion and the second portion And transferring the first portion to the cracker and transferring the second portion to the splitter column. An embodiment of the present invention is one, any or all of the third embodiment of the present paragraph to the third embodiment of the paragraph, further comprising operating the splitter column and the separation device to maintain delivery to the catalytic recombination device Constant mass flow. An embodiment of the invention is one, any or all of the preceding embodiments of the present paragraph to the third embodiment of the paragraph wherein the cracking unit is a catalytic naphtha cracker or a naphtha steam cracker. An embodiment of the invention is one, any or all of the embodiments of the preceding paragraphs to the third embodiment of the paragraph wherein the hydrocarbon stream is a straight run naphtha stream.

A fourth embodiment of the present invention is a method of producing light olefins, the method comprising: transferring a hydrocarbon stream to a first separation column to generate a first light stream and a first heavy stream; and conveying the first heavy stream To a hydrotreating unit to produce a treated heavy stream; the treated heavy stream is passed to a second separation unit to produce a first extract stream comprising linear hydrocarbons and a raffinate stream comprising non-linear hydrocarbons And transferring the first light stream and the first extract stream to the cracking unit To produce light olefins. An embodiment of the present invention is one, any or all of the preceding embodiments of the present paragraph to the fourth embodiment of the paragraph, further comprising transferring the raffinate stream to the recombination device. An embodiment of the present invention is one, any or all of the preceding embodiments of the present paragraph to the fourth embodiment of the paragraph wherein the first light stream comprises C5 hydrocarbons. An embodiment of the present invention is one, any or all of the preceding embodiments to the fourth embodiment of the paragraph, wherein the first light stream comprises methylcyclopentane and a lighter hydrocarbon . An embodiment of the present invention is one, any or all of the preceding embodiments of the present paragraph to the fourth embodiment of the paragraph, wherein the cracking device generates a cracker heavy stream and further comprising transporting the cracker heavy stream To the reorganization device. An embodiment of the invention is one, any or all of the embodiments of the preceding paragraph to the fourth embodiment of the paragraph wherein the cracking unit is a catalytic cracking unit. An embodiment of the invention is one, any or all of the embodiments of the preceding paragraphs to the fourth embodiment of the paragraph, wherein the cracking unit is a steam cracking unit. An embodiment of the invention is one, any or all of the preceding embodiments of the present paragraph to the fourth embodiment of the paragraph wherein the hydrocarbon stream is a straight run naphtha stream. An embodiment of the present invention is one, any or all of the embodiments of the previous embodiment to the fourth embodiment of the paragraph, wherein the second separating device is an adsorptive separation device.

A fifth embodiment of the invention is a process for producing a light olefin comprising conveying a cracker feed stream to a cracking unit (including splitting a hydrocarbon feed stream into a first portion and a second portion); Transfer to the first separation unit to produce an extract stream comprising linear paraffins and a raffinate stream comprising non-linear paraffins; and conveying the extract stream to the second portion to the cracking unit. An embodiment of the present invention is one, any or all of the fifth embodiment of the present paragraph to the fifth embodiment of the present paragraph, wherein the method further comprises transmitting the first portion to the second separating device to generate light a top stream and a heavy bottoms residual stream; transferring the heavy bottoms residual stream to the first separation unit; and delivering the light overhead stream to the cracking unit. An embodiment of the present invention is one, any or all of the fifth embodiment of the present paragraph to the fifth embodiment of the paragraph, further comprising a heavy bottom The leave stream is passed to a hydrotreating unit to produce a treated heavy bottoms residual stream; and the treated bottoms residual stream is passed to a first separation unit. An embodiment of the present invention is one, any or all of the fifth embodiment of the present paragraph to the fifth embodiment of the present paragraph, wherein the first separation device is an adsorption separation device and the second separation device is a fractionation column. An embodiment of the present invention is one, any or all of the fifth embodiment of the present paragraph to the fifth embodiment of the paragraph wherein the hydrocarbon feed stream is a straight run naphtha stream. An embodiment of the present invention is one, any or all of the fifth embodiment of the previous embodiment to the fifth paragraph of the paragraph, further comprising transferring the raffinate stream to the recombination device. An embodiment of the present invention is one, any or all of the fifth embodiment of the previous embodiment to the fifth embodiment of the present invention, wherein the reconstituting device is a continuous catalyst regeneration process. An embodiment of the present invention is one, any or all of the fifth embodiment of the present paragraph to the fifth embodiment of the present paragraph, wherein the cracking device generates a heavy by-product stream, and the processing further comprises placing the heavy by-product The product is transferred to a reconstitution device. An embodiment of the present invention is one, any or all of the fifth embodiment of the present paragraph to the fifth embodiment of the present paragraph, wherein the splitting of the hydrocarbon feed stream is sized to maintain a constant feed of the cracking unit rate.

A sixth embodiment of the invention is a process for producing light olefins from a straight run naphtha feed stream, the method comprising splitting a naphtha feed stream into a first portion and a second portion; conveying the first portion to the stone a brain oil splitter fractionator to produce a light overhead stream and a heavy bottoms residual stream; the heavy bottoms residual stream is passed to a naphtha hydrotreating unit to produce a hydrotreated naphtha stream; The treated naphtha stream is passed to an adsorption separation unit to produce an extract stream and a raffinate stream; the extract stream, the light overhead stream and the second portion are passed to the naphtha cracking unit; and the raffinate stream is passed to the recombination unit in. An embodiment of the present invention is one, any or all of the sixth embodiment of the present paragraph to the sixth embodiment of the paragraph, further comprising a splitting and naphtha splitter for controlling the naphtha feed stream The operation of the fractionation column produces a constant total flow rate that is delivered to the naphtha cracker.

Without further detailed description, those skilled in the art can use the most described previously. The invention is to be construed as being limited by the scope of the invention, and various changes and modifications of the invention may be made to the various uses and conditions without departing from the spirit and scope of the invention. Accordingly, the preferred embodiment of the invention is to be construed as illustrative only, and not limited by the scope of the invention.

Unless otherwise indicated, in the foregoing, all temperatures are stated in degrees Celsius, all parts and percentages are by weight.

6‧‧‧Second hydrocarbon stream

8‧‧‧ hydrocarbon feed stream / straight run naphtha feed stream

10‧‧‧First separation tower/naphtha splitter

12‧‧‧First Light Stream / Top Flow

14‧‧‧First Heavy Stream/Heavy Bottom Residue Logistics

20‧‧‧Hydrogenation unit

22‧‧‧Processed heavy flow

30‧‧‧Second separation device

32‧‧‧First extraction stream

34‧‧‧Rust logistics

40‧‧‧Cleaning device

50‧‧‧Reorganization device

52‧‧‧Processing flow

Claims (10)

A method of optimizing production of downstream operations in the production of light olefins and aromatics, comprising: transferring a first hydrocarbon stream to a first separation column to produce a first light stream and a first heavy stream Transferring the first heavy stream to a hydrotreating unit to produce a processed heavy stream; transferring the processed heavy stream to a second separating unit to generate a first extract stream and a raffinate stream; And delivering the first extract stream, the first light stream, and the second hydrocarbon stream to a cracking unit. The method of claim 1, wherein the total flow rate delivered to the cracking device is kept constant. The method of claim 1, wherein the first light stream comprises C5 hydrocarbons. The method of claim 1, wherein the first light stream comprises methylcyclopentane and a lighter hydrocarbon. The method of claim 1, wherein the cracking device generates a cracker residual stream, and further comprising conveying the cracker residual stream to a recombination unit. The method of claim 1, wherein the first extract stream comprises a linear hydrocarbon, and the raffinate stream comprises a non-linear hydrocarbon; and the first light stream and the first extract stream are passed to a cracking unit to generate Light olefins. The method of claim 1, further comprising transferring the raffinate stream to a reconstitution device. The method of claim 6, wherein the cracking device generates a cracker heavy stream, and further The step includes delivering the cracker heavy stream to the recombination unit. The method of claim 6, wherein the second separation device is an adsorption separation device. The method of claim 6, further comprising operating the first separation column and operating the second separation column, wherein the generation of the first light flow and the generation of the first extraction flow are maintained constant to feed the cracking device Feed rate.