阅读说明：本技术 使用精馏和吸附剂从丁烷和丁烯的混合物中分离烯烃成分 (Separation of olefinic components from mixtures of butanes and butenes using rectification and adsorbents ) 是由 穆罕默德·阿尔多斯萨里 穆罕默德·纳迪姆·沙伊克 哈利德·A·马杰努尼 艾哈迈德·阿尔泽奈迪 于 2019-12-17 设计创作，主要内容包括：公开了用于分离烯烃C-4和烷烃C-4成分的混合物的系统和方法。所述系统和方法包括用于从混合物中分离成分的吸附设备和吸附方法。(Disclosed is a process for separating an olefin C 4 And alkane C 4 Systems and methods for a mixture of ingredients. The systems and methods include an adsorption apparatus and an adsorption process for separating components from a mixture.)

1. From C₄A process for recovering olefins from a hydrocarbon mixture, the process comprising:

fraction C in the first separation stage₄A hydrocarbon mixture to form (1) a first olefin stream comprising predominantly 1-butene and isobutylene together and (2) a first byproduct stream comprising predominantly cis-2-butene and trans-2-butene together; and is

The first olefin stream is separated by a second separation section adapted to separate the hydrocarbon stream by adsorption to form an isobutylene stream comprising primarily isobutylene and a 1-butene stream comprising primarily 1-butene.

2. The method of claim 1, wherein the first separation section comprises a first rectification column.

3. The process of any of claims 1-2, wherein the first olefin stream further comprises isobutane and the first byproduct stream further comprises n-butane.

4. The process of any one of claims 1 to 2, wherein the second separation section comprises one or more adsorber units.

5. The process of any of claims 1-2, wherein the second separation section separates the first olefin stream into (a) a second olefin stream comprising primarily isobutylene and 1-butene together and (b) an isobutane stream comprising primarily isobutane.

6. The method of claim 5, further comprising:

the second olefinic stream is separated into an isobutene stream comprising predominantly isobutene and a 1-butene stream comprising predominantly 1-butene.

7. The process of claim 6, wherein the separation of the second olefin stream is performed by a molecular sieve unit.

8. The process of any of claims 1-2, wherein the second separation section separates the first olefin stream into (a) a second olefin stream comprising primarily isobutylene and isobutane together and (b) a 1-butene stream comprising primarily 1-butene.

9. The method of claim 8, further comprising:

the second olefinic stream is separated into an isobutene stream comprising mainly isobutene and an isobutane stream comprising mainly isobutane.

10. The process of claim 9, wherein the separation of the second olefin stream is performed by the second rectification column.

11. The method of any one of claims 1 and 2, wherein C is₄The hydrocarbon mixture is supplied to a first separation section selected from the group consisting of: steam crackers, catalytic dehydrogenation units, and combinations thereof.

12. The process of any of claims 1 and 2, wherein the first olefin stream comprises (a) olefins from C₄40 to 80% by weight of 1-butene of a hydrocarbon mixture and (b) from C₄20 to 50 wt.% of the hydrocarbon mixture% of isobutylene.

13. The process of any one of claims 1 and 2, wherein the first byproduct stream comprises a stream from C₄10 to 30% by weight of cis-2-butene and C-derived hydrocarbons of a hydrocarbon mixture₄40 to 60 weight percent trans-2-butene of the hydrocarbon mixture.

14. The process according to any one of claims 1 and 2, wherein the second separation stage is selected from the group consisting of: temperature swing adsorbers, pressure swing adsorbers, and combinations thereof.

15. The process of any one of claims 1 and 2, wherein the second separation section comprises a plurality of vessels having adsorbent beds, and during operation, at least one vessel is in an adsorption mode and at least one vessel is in a regeneration mode.

16. The method according to any one of claims 1 and 2, wherein C is selected from C₄The ratio of isobutene recovery from the hydrocarbon mixture is at least 60% by weight or preferably more than 80% by weight or more preferably more than 90% by weight and from C₄The ratio of 1-butene recovery from the hydrocarbon mixture is at least 60 wt% or preferably greater than 80 wt% or more preferably greater than 90 wt%.

17. The process according to any one of claims 1 to 2, wherein the purity of isobutene is at least 90% by weight or preferably more than 95% by weight or more preferably more than 99% by weight and the purity of 1-butene is at least 90% by weight or preferably more than 95% by weight or more preferably more than 99% by weight.

18. From C₄A process for recovering olefins from a hydrocarbon mixture, the process comprising:

separation of C in adsorber section₄A hydrocarbon mixture to form (1) a first olefin stream comprising predominantly butene-1 and isobutylene together and (2) a first byproduct stream comprising predominantly cis-2-butene, trans-2-butene, n-butane, and isobutane together;and is

The first olefin stream is separated by molecular sieves into an isobutylene stream comprising primarily isobutylene and a 1-butene stream comprising primarily 1-butene.

19. The process of claim 18, wherein the separation of the first olefin stream comprises adsorption of isobutene.

20. The process of claim 18, wherein the separation of the first olefin stream comprises adsorbing 1-butene.

Technical Field

The present invention relates generally to the separation of a multi-component hydrocarbon stream. More particularly, the invention relates to the separation of mixtures comprising butanes and butenes using rectification and adsorption processes.

Background

Steam cracking unit and Fluid Catalytic Cracker (FCC) production C for olefin plants₄A mixture of fractions. Usually, from C₄Butadiene is extracted from a mixture of fractions, and the resulting C of n-butane, isobutane (i-butane), isobutene (i-butene) and mixtures of n-butenes is generally retained after extraction of butadiene from the mixture₄And (4) streaming. Conventionally, mixed C's are synthesized using a process for synthesizing methyl tert-butyl ether (MTBE)₄The 1-butene and isobutene in the stream are separated from each other. In this process, the mixed C is treated in a reactor₄Stream, isobutylene is converted to MTBE in the reactor using methanol as a reactant. After the reaction is complete, the mixed C depleted in isobutylene is separated from the MTBE and methanol using reactive distillation and conventional distillation methods₄And (4) streaming. Rectification process to recover butenes (1-butene, cis-2-butene (C-butene) and trans-2-butene (t-butene)), while C₄The alkanes are recycled to, for example, a catalytic cracker.

Disclosure of Invention

A process has been found for cracking olefins C obtained from a steam cracker or fluid catalytic cracker₄And alkane C₄The mixture of fractions is separated into its components. The process may involve recovering olefins from a feedstock containing olefins C₄And alkane C₄Separating the isobutylene and 1-butene from the combined stream.

Embodiments of the invention include from C₄A process for recovering olefins from a hydrocarbon mixture. The process comprises fractionating C in a first separation section₄The hydrocarbon mixture to form (1) a first olefin stream comprising predominantly 1-butene and isobutylene together and (2) a first byproduct stream comprising predominantly cis-2-butene and trans-2-butene together. The process also includes separating the first olefin stream by a second separation section to form an isobutylene stream comprising primarily isobutylene and a 1-butene stream comprising primarily 1-butene. The second separation section is adapted to separate the hydrocarbon stream by adsorption.

Embodiments of the invention include from C₄A process for recovering olefins from a hydrocarbon mixture. The process includes separating C in an adsorber section₄The hydrocarbon mixture to form (1) a first olefin stream comprising predominantly butene-1 and isobutylene together and (2) a first byproduct stream comprising predominantly cis-2-butene, trans-2-butene, n-butane, and isobutane together. The process also includes separating the first olefin stream into an isobutylene stream comprising primarily isobutylene and a 1-butene stream comprising primarily 1-butene via a molecular sieve.

The following includes definitions of various terms and phrases used throughout this specification.

The term "about" or "approximately" is defined as being approximately as understood by one of ordinary skill in the art. In one non-limiting embodiment, the term is defined as being within 10%, preferably within 5%, more preferably within 1%, and most preferably within 0.5%.

The terms "weight percent," "volume percent," or "mole percent," refer to the weight percent of an ingredient, the volume percent of an ingredient, or the mole percent of an ingredient, respectively, based on the total weight, volume, or total moles of the material comprising the ingredient. In a non-limiting example, 10 mole composition in 100 moles of material is 10 mole% composition.

The term "substantially" as used in the specification and/or claims refers to any of greater than 50% by weight, 50% by mole, and 50% by volume. For example, "predominantly" can include 50.1% to 100% by weight and all values and ranges therebetween, 50.1% to 100% by mole and all values and ranges therebetween, and 50.1% to 100% by volume and all values and ranges therebetween.

The term "substantially" and variations thereof are defined as being within 10%, within 5%, within 1%, or within 0.5%.

The terms "inhibit" or "reduce" or "prevent" or "avoid" or any variation of these terms, when used in the claims and/or the specification, includes any measurable reduction or complete inhibition to achieve a desired result.

The term "effective" as used in the specification and/or claims means sufficient to achieve a desired, expected, or intended result.

When used in the claims or the specification with the terms "comprising," including, "" containing, "or" having, "no preceding numerical term of an element may mean" one, "but it is also intended to conform to the meaning of" one or more, "" at least one, "and" one or more than one.

The words "comprising," "having," "including," or "containing" are inclusive or open-ended and do not exclude additional, unrecited elements or method steps.

The methods of the present invention can "comprise," consist essentially of, "or" consist of the particular components, ingredients, compositions, etc. disclosed throughout this specification.

Other objects, features and advantages of the present invention will become apparent from the following drawings, detailed description and examples. It should be understood, however, that the drawings, detailed description and examples, while indicating specific embodiments of the present invention, are given by way of illustration only and are not intended to be limiting. In addition, it is expected that variations and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. In other embodiments, features from specific embodiments may be combined with features from other embodiments. For example, features from one embodiment may be combined with features from any of the other embodiments. In other embodiments, additional features may be added to the specific embodiments described herein.

Drawings

For a more complete understanding, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:

FIG. 1 shows a slave C according to an embodiment of the present invention₄A system for recovering olefins from a hydrocarbon mixture;

FIG. 2 shows a method for slave C according to an embodiment of the invention₄A process for recovering olefins from a hydrocarbon mixture;

FIG. 3 shows a schematic diagram for a slave C according to an embodiment of the present invention₄A system for recovering olefins from a hydrocarbon mixture;

FIG. 4 shows a schematic diagram for a slave C according to an embodiment of the present invention₄A process for recovering olefins from a hydrocarbon mixture;

FIG. 5 shows a schematic diagram for a slave C according to an embodiment of the present invention₄A system for recovering olefins from a hydrocarbon mixture; and

FIG. 6 shows a schematic diagram for a slave C according to an embodiment of the present invention₄A process for recovering olefins from a hydrocarbon mixture.

Detailed Description

Has been found to be useful for cracking olefins C obtained from steam or fluid catalytic crackers₄And alkane C₄Of fractionsSeparating the mixture into its components. The process may involve recovering olefin C from a feedstock containing olefin₄And alkane C₄Separating the isobutylene and 1-butene from the combined stream.

FIG. 1 shows a schematic diagram for a slave C according to an embodiment of the present invention₄A system 10 for recovering olefins from a hydrocarbon mixture. The system 10 relates to the integration of a rectification device and an adsorption device for the secondary C₄A process for recovering olefins from a hydrocarbon mixture. FIG. 2 shows a schematic diagram for a slave C according to an embodiment of the present invention₄A process 20 for recovering olefins from a hydrocarbon mixture. Method 20 may be implemented with system 10.

Fig. 1 shows the integration of a rectification column 101, an adsorption unit 102, and a molecular sieve unit 103. As shown, the first separation section 10A may include a rectification column 101 and the second separation section 10B may include one or more adsorber units such as an adsorption unit 102 and a molecular sieve unit 103. Method 20, as implemented by system 10, begins at block 200, which involves assigning C, according to an embodiment of the present invention₄The hydrocarbon mixture 100 (from, for example, a steam cracker, a catalytic dehydrogenation unit, or a combination thereof) flows to the first separation section 10A. In an embodiment of the invention, the effluent from the steam cracker, catalytic dehydrogenation unit, or combination thereof is subjected to a process for removing butadiene, which produces C comprising isobutane, isobutylene, 1-butene, cis-2-butene, trans-2-butene, and n-butane₄A hydrocarbon mixture 100. In an embodiment of the invention, C₄The hydrocarbon mixture 100 comprises 1.0 to 2.0 mole% isobutane, 16.0 to 26.0 mole% isobutene, 35 to 53 mole% 1-butene, 5.0 to 9.0 mole% cis-2-butene, 12.0 to 22.0 mole% trans-2-butene, and 4.0 to 10.0 mole% n-butane.

At block 201, rectification column 101 processes C₄A hydrocarbon mixture 100, thereby performing a crude separation of the components. Block 201 may include rectifying column 101 rectification C₄The hydrocarbon mixture 100 to produce a distillate (i.e., first olefin stream 104) and a bottoms stream (i.e., first byproduct stream 105). According to an embodiment of the invention, the first olefin stream 104 comprises predominantly (greater than 50 wt.%) together 1-butene and iso-butaneThe olefins, and the first byproduct stream 105 comprises primarily cis-2-butene and trans-2-butene together. In an embodiment of the invention, the first olefin stream 104 collectively comprises from 0.1 mol% to 4.0 mol% isobutane, from 20 mol% to 40 mol% isobutene, from 60 mol% to 70 mol% 1-butene, from 0.1 mol% to 1 mol% cis-2-butene, trans-2-butene, and n-butane. In an embodiment of the invention, the first byproduct stream 105 solids comprises 18 to 26 mole% cis-2-butene, 50 to 60 mole% trans-2-butene, 18 to 26 mole% n-butane, 0.5 to 2.0 mole% 1-butene, isobutene, and isobutane. The rectification conditions of the rectification column 101 may include a temperature of 20 ℃ to 100 ℃ and a pressure of 1 bar to 20 bar.

The process 20 continues at block 202, which involves flowing the first olefin stream 104 from the rectifier 101 (first separation section 10A) to the second separation section 10B, separating the first olefin stream 104 at the second separation section, block 203, to produce an isobutene stream 108 comprising primarily isobutene, a 1-butene stream 109 comprising primarily 1-butene, and an isobutane stream 107 comprising primarily isobutane. The second separation section 10B is adapted to separate the hydrocarbon stream at least by adsorption, for example by using an adsorption unit 102 and a molecular sieve unit 103.

According to fig. 1 and 2, block 203 may be performed by blocks 203a to 203 c. Block 203a may include the adsorption unit 102 processing the first olefin stream 104 (which includes butene-1, isobutylene, and isobutane) in the second separation section 10B such that the isobutane stream 107 (which includes primarily isobutane) is separated from the second olefin stream 106 (whose primary solids include a mixture of isobutylene and butene-1). The separation is achieved by the adsorption method in the adsorption unit 102.

According to an embodiment of the invention, block 203 further comprises flowing the second olefinic stream 106 from the adsorption unit 102 to the molecular sieve unit 103 at block 203 b. At block 203c, the process 20 may further include separating the second olefinic stream 106 into an isobutene stream 108 (comprising primarily isobutene) and a 1-butene stream 109 (comprising primarily 1-butene) via the molecular sieve unit 103. In an embodiment of the invention, the isobutylene stream 108 comprises 90 to 99.9 wt.% isobutylene and 0.1 to 10 wt.% 1-butene, among others. In an embodiment of the invention, the 1-butene stream 109 comprises 90 to 99.9 wt% 1-butene and 0.1 to 10 wt% isobutene, among others.

The adsorption process occurring in adsorption unit 102 and the molecular sieve process occurring in molecular sieve unit 103 are both based on the adsorption principle to achieve separation. The difference between the adsorption process occurring in adsorption unit 102 and the molecular sieve process occurring in molecular sieve unit 103 is the type of material used to effect the separation, according to an embodiment of the present invention. Thus, the operating principles described herein relating to adsorption are relevant to both the adsorption process occurring in adsorption unit 102 and the molecular sieve process occurring in molecular sieve unit 103, both of which are transient processes. The adsorption unit 102 and the molecular sieve unit 103 may include multiple vessels (e.g., two or three). Each of adsorption unit 102 and molecular sieve unit 103 may include one or more beds of adsorbent material. In embodiments of the invention, the adsorbent of the adsorption unit 102 comprises zeolites (silica and alumina), metals (copper, potassium, sodium), or combinations thereof. In an embodiment of the invention, the molecular sieve of molecular sieve unit 103 comprises 5A, or 13X, or Y-zeolite or modified 13X or Y-zeolite, or silicalite or high silicon ZSM-5 or combinations thereof. The isobutylene adsorbed in the molecular sieve unit 103 may be desorbed using a Pressure Swing Adsorption (PSA)/desorption method or a Temperature Swing Adsorption (TSA)/desorption method. The adsorbed material is desorbed from the molecular sieve by varying the pressure or temperature. If pressure swing is used, the pressure needs to be reduced in order to desorb the adsorbed species. If a temperature swing process is used, the increase in temperature will cause the adsorbed species to desorb.

As the separated fluid moves through the beds of the adsorption unit 102 and the beds of the molecular sieve unit 103, it contacts the adsorbent at the bed inlet and some molecules are adsorbed. The adsorbed molecules are called adsorbates. At the beginning of the adsorption process, the region at the bed inlet is referred to as the active zone or Mass Transfer Zone (MTZ). Over time, the adsorbent material at the bed inlet becomes saturated (indicating that the adsorption rate equals the desorption rate) and the MTZ moves further down the length of the bed. The saturated region in the bed is called the Equilibrium Zone (EZ). After a sufficient period of time, the entire bed is in equilibrium and a breakthrough of adsorbate occurs. At which point the bed is unable to effectively separate the fluid to be separated.

Thus, for a continuous, uninterrupted process, multiple vessels (each containing a bed of adsorbent material) are used in performing method 20, and the vessels are operated in an interleaved manner. For example, one vessel with the bed of adsorption unit 102 and one vessel with the bed of molecular sieve unit 103 are in an operating or adsorption mode while another vessel with the bed of adsorption unit 102 and another vessel with the bed of molecular sieve unit 103 are in a regeneration mode, and optionally, a third vessel with the bed of adsorption unit 102 and a third vessel with the bed of molecular sieve unit 103 are in a standby mode.

According to an embodiment of the invention, in the method 20, when a particular bed of the adsorption unit 102 becomes saturated, the fluid stream may be diverted to the bed of the adsorption unit 102 in the standby mode. Similarly, when a particular bed of the molecular sieve unit 103 becomes saturated, the fluid stream may be diverted to the bed of the molecular sieve unit 103 in the standby mode. The corresponding saturated bed is then regenerated by desorbing the adsorbate.

In the process 20, a variety of techniques are available and can be implemented as needed to regenerate the saturated bed. These include reducing the pressure of the saturated bed (pressure swing), increasing the temperature of the saturated bed (temperature swing), or passing an inert gas or solvent through the saturated bed, thereby stripping the adsorbate from the adsorbent material. In an embodiment of the invention, the second separation section 10B is selected from: temperature swing adsorbers, pressure swing adsorbers, and combinations thereof.

In an embodiment of the invention, the adsorption unit 102 comprises a temperature swing adsorber comprising an adsorbent comprising a 5A or 13X or Y-zeolite or a modified 13X or Y-zeolite or a silicalite or a high silica ZSM-5 or combinations thereof. In an embodiment of the invention, the adsorption unit 102 comprises a pressure swing adsorber comprising an adsorbent comprising 5A or 13X or Y-zeolite or modified 13X or Y-zeolite or silicalite or high silica ZSM-5 or combinations thereof. In an embodiment of the invention, process 20 includes desorbing isobutylene from the molecular sieve of molecular sieve unit 103 at block 203.

FIG. 3 shows a schematic diagram for a slave C according to an embodiment of the present invention₄A system 30 for recovering olefins from a hydrocarbon mixture. The system 30 relates to the integration of a rectification device and an adsorption device for the secondary C₄A process for separating olefins from a hydrocarbon mixture. FIG. 4 shows a schematic diagram for a slave C according to an embodiment of the present invention₄A process 40 for recovering olefins from a hydrocarbon mixture. The method 40 may be implemented with the system 30.

Fig. 3 shows the integration of a rectification column 301, a molecular sieve unit 302 and a rectification column 303. As shown, the first separation section 30A may include a rectification column 301 and the second separation section 30B may include one or more separation units such as a molecular sieve unit 302 and a rectification column 303. Method 40, as implemented by system 30, begins at block 400, which involves assigning C, according to an embodiment of the present invention₄The hydrocarbon mixture 300 (from, for example, a steam cracker, a catalytic dehydrogenation unit, or a combination thereof) flows to the first separation section 30A. In an embodiment of the invention, the effluent from the steam cracker, catalytic dehydrogenation unit or combination thereof is subjected to a process for removing butadiene, which results in the formation of C comprising isobutane, isobutene, 1-butene, cis-2-butene, trans-2-butene and n-butane₄A hydrocarbon mixture 300. In an embodiment of the invention, C₄The hydrocarbon mixture 300 comprises 1.0 to 2.0 mole% isobutane, 16.0 to 26.0 mole% isobutene, 35 to 53 mole% 1-butene, 5.0 to 9.0 mole% cis-2-butene, 12.0 to 22.0 mole% trans-2-butene, and 4.0 to 10.0 mole% n-butane.

At block 401, rectification column 301 processes C₄A hydrocarbon mixture 300, thereby performing a crude separation of the components. Block 401 may include rectification column 301, which rectifies C₄The hydrocarbon mixture 300 to produce a distillate (i.e., first olefin stream 304) and a bottoms stream (i.e., first byproduct stream 305). According to embodiments of the invention, the first olefin stream 304 comprises predominantly (greater than 50 wt%) 1-butene and isobutylene together, and the first byproduct stream 305 comprises predominantly cis-2-butene and trans-2-butene together. In the practice of the inventionIn a scheme, the first olefin stream 304 collectively comprises from 0.1 to 4.0 mole percent isobutane, from 20 to 40 mole percent isobutylene, from 60 to 70 mole percent 1-butene, and from 0.1 to 1 mole percent cis-2-butene, trans-2-butene, and n-butane. In an embodiment of the invention, the first byproduct stream 305 collectively comprises from 18 mol% to 26 mol% cis-2-butene, from 50 mol% to 60 mol% trans-2-butene, from 18 mol% to 26 mol% n-butane, and from 0.5 mol% to 2.0 mol% 1-butene, isobutene, and isobutane. The rectification conditions of the rectification column 301 may include a temperature of 20 ℃ to 100 ℃ and a pressure of 1 bar to 20 bar.

The process 40 continues at block 402, which involves flowing the first olefin stream 304 from the rectifier 301 (first separation section 30A) to the second separation section 30B, separating the first olefin stream 304 at the second separation section 30B, block 403, to produce an isobutane stream 308 comprising primarily isobutane, an isobutene stream 309 comprising primarily isobutene, and a 1-butene stream 307 comprising primarily 1-butene. The second separation section 30B may be adapted to separate the hydrocarbon stream at least by adsorption; for example, using molecular sieve unit 302. In addition, rectification column 303 may be used for further separation, as shown.

According to fig. 3 and 4, block 403 may include block 403a in which the molecular sieve unit 302 processes the first olefin stream 304 (which includes 1-butene, isobutene, and isobutane) in the second separation section 30B such that a 1-butene stream 307 (which includes primarily 1-butene) is separated from the second olefin stream 306 (which collectively includes primarily a mixture of isobutane and isobutene). The separation is achieved by an adsorbent process in molecular sieve unit 302.

According to an embodiment of the invention, block 403 further includes block 403b, which involves flowing the second olefinic stream 306 from the molecular sieve unit 302 to the rectification column 303. At block 403c, the method 40 may further include separating the second olefinic stream 306 into an isobutane stream 308 (comprising primarily isobutane) and an isobutene stream 309 (comprising primarily isobutene) via the rectifier 303. In an embodiment of the invention, the isobutane stream 308 comprises from 90 wt% to 99.9 wt% isobutane and from 0.1 wt% to 10 wt% isobutene, among others. In an embodiment of the invention, the isobutylene stream 309 comprises 90 wt.% to 99.9 wt%And 0.1 to 10% by weight of isobutene, and others. In the embodiments of the invention described herein, from C₄The ratio of recovery of isobutene in the hydrocarbon mixture is at least 60% by weight or preferably more than 80% by weight or more preferably more than 90% by weight and from C₄The ratio of 1-butene recovered in the hydrocarbon mixture is 60% by weight or preferably more than 80% by weight or more preferably more than 90% by weight. In an embodiment of the invention, the purity of the isobutene is at least 90% by weight or preferably more than 95% by weight or more preferably more than 99% by weight; and the purity of 1-butene is at least 90 wt% or preferably greater than 95 wt% or more preferably greater than 99 wt%.

The mechanism of the adsorption process occurring in molecular sieve unit 302 is the same as described above with respect to molecular sieve unit 103.

FIG. 5 shows a process for separating C according to an embodiment of the invention₄A system 50 of hydrocarbon mixtures. System 50 includes an adsorption unit 501 and a molecular sieve unit 502. FIG. 6 shows a schematic diagram for a slave C according to an embodiment of the present invention₄A process for recovering olefins from a hydrocarbon mixture. The method 60 may be implemented using the system 50, according to an embodiment of the present invention.

Method 60 may begin at block 600, which involves causing C to be performed, according to an embodiment of the present invention₄The hydrocarbon mixture 500 flows to an adsorption unit 501. C₄The hydrocarbon mixture 500 may have C₄Composition of the hydrocarbon mixture 100. At block 601, the adsorption unit 501 is driven from C₄Isobutylene and 1-butene are adsorbed in the hydrocarbon mixture 500 to form a first olefin stream 503 (comprising primarily 1-butene and isobutylene together) and a first byproduct stream 504 (comprising primarily cis-2-butene, trans-2-butene, n-butane, and isobutane together). In an embodiment of the invention, the first olefin stream 503 comprises 40 to 80 wt% 1-butene, 20 to 50 wt% isobutene, and 0.1 to 40 wt% any combination of cis-2-butene, trans-2-butene, n-butane, and isobutane. In an embodiment of the invention, the first byproduct stream 504 comprises from 10 wt% to 30 wt% cis-2-butene, from 40 wt% to 60 wt% trans-2-butene, from 10 wt% to 30 wt% n-butane, from 1 wt% to 10 wt%And 0.1 to 10 weight percent of 1-butene and isobutylene. At block 602, the process 60 may also include flowing the first olefin stream 503 from the adsorption unit 501 to the molecular sieve unit 502. At block 603, the molecular sieve unit 502 separates the first olefin stream 503 into an isobutylene stream 505 comprising primarily isobutylene and a 1-butene stream 506 comprising primarily 1-butene. According to an embodiment of the invention, the separation of the first olefin stream 503 at block 603 includes adsorption of isobutylene. In an embodiment of the invention, the isobutylene stream 505 comprises from 90 wt% to 99.9 wt% isobutylene and from 0.1 wt% to 10 wt% 1-butene. In an embodiment of the invention, the 1-butene stream 506 comprises from 90 wt% to 99.9 wt% 1-butene and from 0.1 wt% to 10 wt% isobutene.

It should be noted that in embodiments of the present invention, isobutylene is selectively adsorbed while 1-butene is not adsorbed and passes through the adsorbent bed. In an embodiment of the invention, 1-butene is selectively adsorbed while isobutylene is not adsorbed and passes through the adsorbent bed. The 1-butene or isobutene can be desorbed by a pressure or temperature swing method. The adsorbed material is desorbed from the molecular sieve by varying the pressure or temperature. If pressure swing is used, the pressure needs to be reduced in order to desorb the adsorbed species. If a temperature swing process is used, the increase in temperature will cause the adsorbed species to desorb.

Although embodiments of the present invention have been described with reference to the blocks of fig. 2, 4, and 6, it should be understood that the operations of the present invention are not limited to the specific blocks and/or specific orders of the blocks illustrated in fig. 2, 4, and 6. Thus, embodiments of the invention may use various blocks in sequences other than those of fig. 2, 4, and 6 to provide the functionality as described herein.

The following includes specific examples as part of the disclosure of the invention. The examples are for illustrative purposes only and are not intended to limit the invention. Those skilled in the art will readily recognize parameters that may be varied or modified to produce substantially the same results.

Examples

Separation C₄Predictive embodiment of a stream

Separation C according to an embodiment of the present invention is described below₄Predictive embodiment of a flow. The feed composition is provided in table 1 below.

Table 1: feed composition

The stream having the composition shown in table 1 above was treated in a rectification column to produce a distillate and a bottoms stream as shown in tables 2 and 3, respectively.

Table 2: distillate composition

Distillate product	Mol% of
		1-butene	65.0
Isobutene	32.3
		Isobutane	2.00
Cis-2-butene, trans-2-butene, n-butane	0.780

Table 3: composition of bottom stream

Bottom stream	Mol% of
		Cis-2-butene	22.1
Trans-2-butene	54.4
		N-butane	22.0
1-butene, isobutene, isobutane	1.52

The rectification is carried out at a pressure such that cooling water is used as a condenser and low-pressure steam is used as a reboiler.

The distillate stream is then further processed in an adsorptive separation process wherein isobutylene and 1-butene are obtained in one stream while isobutane and minor amounts of trans-2-butene, cis-2-butene and n-butane are obtained in another stream. Finally, isobutene and 1-butene are separated by a molecular sieve method.

In an embodiment of the invention, stream 106 may contain 50 to 70 wt% 1-butene, 20 to 40 wt% isobutene, and 0.1 to 10 wt% isobutane. Stream 107 can contain 90 wt% to 99.9 wt% isobutane and 0.1 wt% to 10 wt% 1-butene and isobutene.

In the context of the present invention, embodiments 1 to 20 are described. Embodiment 1 is from C₄Recovery of olefins from hydrocarbon mixturesThe method of (1). The process comprises fractionating C in a first separation section₄A hydrocarbon mixture to form: (1) a first olefin stream comprising predominantly 1-butene and isobutylene in common, and (2) a first byproduct stream comprising predominantly cis-2-butene and trans-2-butene in common. The process also includes separating the first olefin stream by a second separation section adapted to separate the hydrocarbon stream by adsorption to form an isobutylene stream comprising primarily isobutylene and a 1-butene stream comprising primarily 1-butene. Embodiment 2 is the method of embodiment 1, wherein the first separation section comprises a first rectification column. Embodiment 3 is the process of any one of embodiments 1 and 2, wherein the first olefin stream further comprises isobutane and the first byproduct stream further comprises n-butane. Embodiment 4 is the method of any one of embodiments 1 to 3, wherein the second separation section comprises one or more adsorber units. Embodiment 5 is the process of any one of embodiments 1 to 4, wherein the second separation section separates the first olefin stream into: (a) a second olefin stream comprising primarily isobutylene and 1-butene together, and (b) an isobutane stream comprising primarily isobutane. Embodiment 6 is the process of embodiment 5, further comprising separating the second olefinic stream into an isobutylene stream comprising primarily isobutylene and a 1-butene stream comprising primarily 1-butene. Embodiment 7 is the method of embodiment 6, wherein the separating of the second olefin stream is performed by a molecular sieve unit. Embodiment 8 is the process of any one of embodiments 1 to 4, wherein the second separation section separates the first olefin stream into: (a) a second olefin stream comprising primarily isobutylene and isobutane together, and (b) a 1-butene stream comprising primarily 1-butene. Embodiment 9 is the process of embodiment 8, further comprising separating the second olefin stream into an isobutylene stream comprising primarily isobutylene and an isobutane stream comprising primarily isobutane. Embodiment 10 is the method of embodiment 9, wherein the separating of the second olefin stream is performed by a second rectification column. Embodiment 11 is the method of any one of embodiments 1 to 10, wherein C₄The hydrocarbon mixture is supplied to a first separation section selected from the group consisting of: steam crackers, catalytic dehydrogenation units, and combinations thereof. Embodiment 12 is the process of any one of embodiments 1 to 11, wherein the first olefin stream comprises: (a) from C₄40 to 80% by weight of 1-butene of a hydrocarbon mixture and (b) from C₄20 to 50 wt.% of isobutene of the hydrocarbon mixture. Embodiment 13 is the method of any one of embodiments 1 to 12, wherein the first byproduct stream comprises a stream from C₄10 to 30% by weight of cis-2-butene and C-derived hydrocarbon mixture₄40 to 60 weight percent trans-2-butene of the hydrocarbon mixture. Embodiment 14 is the process of any one of embodiments 1 to 13, wherein the second separation stage is selected from the group consisting of temperature swing adsorbers, pressure swing adsorbers, and combinations thereof. Embodiment 15 is the process of any one of embodiments 1 to 14, wherein the second separation section comprises a plurality of vessels having adsorbent beds, and during operation, at least one vessel is in an adsorption mode and at least one vessel is in a regeneration mode. Embodiment 16 is the method of any one of embodiments 1 to 15, wherein C is substituted with C₄The ratio of recovery of isobutene in the hydrocarbon mixture is at least 60% by weight or preferably more than 80% by weight or more preferably more than 90% by weight and from C₄The ratio of 1-butene recovered in the hydrocarbon mixture is 60% by weight or preferably more than 80% by weight or more preferably more than 90% by weight. Embodiment 17 is the process of any one of embodiments 1 to 16, wherein the isobutylene has a purity of at least 90 wt.% or preferably greater than 95 wt.% or more preferably greater than 99 wt.%, and the 1-butene has a purity of at least 90 wt.% or preferably greater than 95 wt.% or more preferably greater than 99 wt.%.

Embodiment 18 is from C₄A process for recovering olefins from a hydrocarbon mixture. The process includes separating C in an adsorber section₄A hydrocarbon mixture to form: (1) a first olefin stream comprising predominantly butene-1 and isobutylene together, and (2) a first byproduct stream comprising predominantly cis-2-butene, trans-2-butene, n-butane, and isobutane. The process also includes separating the first olefin stream into an isobutylene stream comprising primarily isobutylene and a 1-butene stream comprising primarily 1-butene via a molecular sieve. Embodiment 19 is the process of embodiment 18, wherein the separating of the first olefin stream comprises adsorbing isobutylene. Embodiment 20 is the process of embodiment 18, wherein the separating of the first olefin stream comprises adsorbing 1-butene.

Although the embodiments of the present application and their advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the embodiments as defined by the appended claims. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the disclosure above, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.