CN113087587A

CN113087587A - Method for separating alkane and olefin by using simulated moving bed

Info

Publication number: CN113087587A
Application number: CN201911341662.4A
Authority: CN
Inventors: 钱震; 张晓龙; 李俊诚; 梁颖堃; 关怀; 菅青娥; 武靖为; 王海国; 高源�; 刘宏宇
Original assignee: Inner Mongolia Yitai Coal Based New Materials Research Institute Co Ltd
Current assignee: Inner Mongolia Yitai Coal Based New Materials Research Institute Co Ltd
Priority date: 2019-12-23
Filing date: 2019-12-23
Publication date: 2021-07-09

Abstract

A process for the separation of alkanes and alkenes using a simulated moving bed comprising eluting with an eluent wherein the eluent is a normal alkane having a carbon number which differs from the carbon number of the alkene in the feed to be separated by more than 1 and less than 7 (e.g. 2, 3, 4, 5 or 6), preferably more than 1 and less than 5 (e.g. 2, 3 or 4). The eluent can reduce the cost and provide the product recovery rate.

Description

Method for separating alkane and olefin by using simulated moving bed

Technical Field

The invention belongs to the technical field of chemical industry, and particularly relates to a method for separating alkane and alkene by using a simulated moving bed.

Background

A simulated moving bed is a mass transfer device that utilizes the adsorption principle for liquid separation operations. The method is a countercurrent continuous operation mode, and produces the effect equivalent to that the adsorbent continuously moves downwards and the material continuously moves upwards by changing the positions of the material inlet and the material outlet of the fixed bed adsorption equipment. The separation of different components in the material is realized according to the different adsorption capacities of the different components in the material on the adsorbent, as shown in fig. 1.

Alpha-olefins are known to mean monoolefins in which the double bond is at the end of the molecular chain. It is an important chemical raw material and an organic synthesis intermediate, and has wide application in the chemical field. It can be used as the synthetic intermediate of surfactant, plasticizer and additive for synthesizing hydrocarbon lubricating oil and oil product. The alpha-olefin also has important application in the industries of spices, paper, daily chemicals and the like.

In the current market, alpha-olefin is mainly derived from methods such as ethylene oligomerization, paraffin cracking, Fischer-Tropsch synthesis and the like. The alpha-olefin produced based on the coal-based Fischer-Tropsch process has continuous carbon number and contains a large amount of alpha-olefin with high carbon number, and has obvious advantages over the ethylene oligomerization process which can only produce even carbon number, but the alpha-olefin produced by the coal-based Fischer-Tropsch process is simultaneously generated along with alkane, so that the method has important significance for effectively separating the alkane and the alkene and improving the additional value of the coal-based Fischer-Tropsch synthesis product.

One prior art method for olefin separation has proposed the use of a simulated moving bed apparatus in which an eluent (desorbent) uses olefins to desorb olefins from an olefin mixture onto an adsorbent. The method does not provide specific implementation effect, but the residual liquid (raffinate) is entrained with olefin so as to reduce the product yield, and the olefin adopted by the eluent has higher cost.

In another existing olefin separation method, the selected eluent is cycloalkane, the eluent can effectively separate alkane and olefin, the dosage of the eluent is not mentioned, but when cycloalkane is used as the eluent, the adsorbed olefin can be desorbed from the adsorbent only by using a great amount of extraction liquid (extraction liquid) to meet the purity requirement, so that the desorption efficiency of the eluent is low, and the olefin separation cost in the extraction liquid is increased.

In the prior technical scheme for separating alkane and olefin by a simulated moving bed, olefin or cycloalkane is adopted as eluent. The olefin as the eluent has the defects of over-quick desorption, low yield caused by the olefin carried in the residual liquid and high cost of the eluent. The cycloalkane used as the eluent has the defects of slow desorption, long separation time, low device efficiency and large eluent consumption.

Disclosure of Invention

The invention provides a method for separating alkane and olefin by using a simulated moving bed, which can effectively improve the yield of olefin and reduce the cost of eluent. In addition, the invention has wider application range and can reduce the energy consumption of the device.

In order to achieve the purpose, the invention adopts the following technical scheme:

a process for the separation of alkanes and alkenes using a simulated moving bed comprising eluting with an eluent wherein the eluent is a normal alkane having a carbon number which differs from the carbon number of the alkene in the feed to be separated by more than 1 and less than 7 (e.g. 2, 3, 4, 5 or 6), preferably more than 1 and less than 5 (e.g. 2, 3 or 4).

In some embodiments, the n-alkane is a n-alkane.

In some embodiments, the n-alkanes are a mixture of n-alkanes, each having a carbon number greater than or less than the carbon number of the alkane and alkene in the feedstock to be separated.

In some embodiments, the operating temperature is from 0 to 250 ℃ (e.g., 20 ℃, 50 ℃, 80 ℃, 100 ℃, 150 ℃ or 200 ℃), preferably from 20 to 100 ℃; the operating pressure is 0 to 2MPa (for example, 0.2MPa, 0.5MPa, 0.8MPa, 1MPa or 1.5MPa), preferably 0 to 1 MPa.

In some embodiments, the method includes the step of removing impurities in the eluent and the material to be separated that affect adsorption effectiveness.

In some embodiments, the process includes the step of separating and recovering the eluent in the extract and raffinate.

In some embodiments, the simulated moving bed comprises an adsorption zone, a purification zone, and a desorption zone.

In some embodiments, the simulated moving bed further comprises a buffer zone.

Compared with the prior art, the method has the following advantages:

1. the eluent selected by the invention is applied, the residual liquid (raffinate) in the separation process of the simulated moving bed is almost not entrained (less than 3 percent), and the product recovery rate is provided.

2. The multiple alkanes in the eluent provided by the invention can belong to different carbon numbers, are more easily obtained and have more flexible mixture ratio.

3. The alkane in the eluent provided by the invention is low in cost and easy to obtain, can be flexibly adjusted according to actual process parameters, and has wide operation conditions.

4. When the carbon number of the eluent is less than that of the olefin in the raw material to be separated, the control difficulty of the rectification process can be reduced, the using amount is small, and the energy consumption is saved.

Drawings

FIG. 1 is the principle of operation of a simulated moving bed;

FIG. 2 is a C14 distribution diagram in a simulated moving bed adsorption tube in example 1 of the present invention;

FIG. 3 is a C14 distribution diagram in a simulated moving bed adsorption tube in example 2 of the present invention;

FIG. 4 is a C10 distribution diagram in a simulated moving bed adsorption tube in example 3 of the present invention;

FIG. 5 is a C10 distribution diagram in a simulated moving bed adsorption tube in example 4 of the present invention;

FIG. 6 is a C14 distribution diagram in a simulated moving bed adsorption tube in example 5 of the present invention;

FIG. 7 is a C10 distribution diagram in a simulated moving bed adsorption tube in example 6 of the present invention;

FIG. 8 is a C14 distribution diagram in a simulated moving bed adsorption tube in example 7 of the present invention;

FIG. 9 is a C10 distribution diagram in a simulated moving bed adsorption tube according to comparative example 1 of the present invention;

FIG. 10 is a C10 distribution diagram in a simulated moving bed adsorption tube in comparative example 2 of the present invention.

Detailed Description

In order that the objects, technical solutions and advantages of the present invention will become more apparent, the present invention will be further described in detail with reference to the accompanying drawings in conjunction with the following specific embodiments.

In the description of the present invention, reference to "one embodiment" means that a particular feature, structure, or parameter, step, or the like described in the embodiment is included in at least one embodiment according to the present invention. Thus, appearances of the phrases such as "in one embodiment," "in one embodiment," and the like in this specification are not necessarily all referring to the same embodiment, nor are other phrases such as "in another embodiment," "in a different embodiment," and the like. Those of skill in the art will understand that the particular features, structures or parameters, steps, etc., disclosed in one or more embodiments of the present description may be combined in any suitable manner.

The Fischer-Tropsch synthesis product mainly comprises a mixture of alkane and olefin, the alkane and the olefin with different carbon numbers can be separated by means of rectification and the like, and the alkane and the olefin with the same carbon number are not easy to be completely separated. The invention uses the simulated moving bed device to separate alkane and alkene, wherein the eluent is an important factor influencing the separation effect.

The invention selects the normal alkane with carbon number different from that of the alkane and the alkene in the separated material as the eluent, can effectively reduce the entrainment of the alkene in the residual liquid (raffinate), improves the product purity and the alkene yield (more than 97 percent), and effectively controls the cost.

The invention provides a method for separating alkane and olefin by using a simulated moving bed, wherein alkane-olefin mixed raw material to be separated passes through the sequential simulated moving bed, the simulated moving bed comprises a plurality of adsorption columns, and the upper end of each adsorption column is provided with a raw material feed valve, a resolving agent feed valve and a circulating liquid feed valve; the lower end of each adsorption column is provided with a raffinate discharge valve and an extract discharge valve.

The adsorption columns are respectively used as an adsorption area, a purification area and a desorption area, wherein the adsorption area is used for adsorbing target product components, and non-target components flow out from an outlet; the purification area is used for purifying the target product components adsorbed in the previous period; the desorption area is used for eluting the target product components purified in the previous period and pumping out the system to achieve the purpose of adsorption separation.

In one embodiment of the present invention, the simulated moving bed may further comprise a buffer zone for accommodating a mixture of a large amount of non-target components and a small amount of target components remaining in the raw material, and waiting for the next cycle to proceed.

Accordingly, in one embodiment of the present invention, the simulated moving bed adsorption separation process is divided into four periods of adsorption, buffering, desorption and purification by using the program control valve set, and the four periods are continuously and sequentially performed by switching the valves.

Taking a simulated moving bed with 8 adsorption columns as an example (the adsorption columns are sequentially called as an adsorption column 1, an adsorption column 2, an adsorption column 3, an adsorption column 4, an adsorption column 5, an adsorption column 6, an adsorption column 7 and an adsorption column 8), in a certain period, the adsorption column 5 and the adsorption column 6 are in an adsorption area, raw materials enter the adsorption column 5 and the adsorption column 6 to adsorb target components, residual liquid is obtained at an outlet, the adsorption column 7 and the adsorption column 8 are in a buffer area, the adsorption column 1 and the adsorption column 2 are in a desorption area, eluent enters the adsorption column 1 and the adsorption column 2, the purified target product components in the previous period are eluted to obtain extract liquid, the adsorption column 3 and the adsorption column 4 are in a purification area, and control valves are switched to change the positions of feeding and discharging materials in different periods, so that the simulated movement of the adsorption area, the purification area, the desorption area and the buffer area is realized, the extraction liquid and the residual liquid are sequentially circulated to obtain the extract liquid (see CN109432822A, the contents of which are incorporated by reference in their entirety). Wherein the eluent is normal alkane, and the difference between the carbon number of the normal alkane and the carbon number of the alkane and the olefin in the raw material to be separated is more than 1 and less than 7 (such as 2, 3, 4, 5 or 6), preferably more than 1 and less than 5 (such as 2, 3 or 4).

In one embodiment of the invention, the eluent is one type of normal alkane, while in other embodiments the eluent is a mixture of normal alkanes, each having a carbon number greater than or less than the carbon number of the alkane and alkene in the feed to be separated.

According to embodiments of the present invention, the operating temperature may be 0 to 250 ℃ (e.g., 20 ℃, 50 ℃, 80 ℃, 100 ℃, 150 ℃, or 200 ℃), preferably 20 to 100 ℃; the operating pressure may be 0 to 2MPa (e.g., 0.2MPa, 0.5MPa, 0.8MPa, 1MPa or 1.5MPa), preferably 0 to 1 MPa.

In some embodiments, the method further comprises the steps of removing impurities in the eluent and the raw material to be separated that affect the adsorption effect and separating and recovering the eluent from the extract and raffinate.

Example 1

The raw material to be separated in this example is a C14 component, and the eluent is a C10 alkane.

C14 raw material: n-tetradecane 30% (w/w), 1-tetradecene 70% (w/w), and prior to the separation of the alkane and alkene, the raw material is pretreated to remove poisons (e.g., oxygen-containing organic compounds, benzene, water, etc.) therein, which may cause adsorption failure.

C10 eluent: n-decane, the eluent is pretreated before the separation of the alkane and alkene to remove poisons (such as oxygen-containing organic compounds, benzene, water and the like) which may cause adsorption failure.

The separation of the C14 feed was carried out in a simulated moving bed unit using C10 eluent. Simulated moving bed operating conditions: the adsorbent adopts molecular sieve adsorbent and modified molecular sieve adsorbent not limited thereto; the temperature operation temperature is 250 ℃; the operating pressure was 2 MPa.

The distribution of C14 in the simulated moving bed adsorption tube is shown in FIG. 2. The results of the chromatographic analysis are shown in Table 1.

TABLE 1

Material(s)	N-tetradecane (%, w/w)	1-tetradecene (%, w/w)	Eluent (content (%, w/w)
				Raw materials	29.98	70.01	-
Eluent	-	-	99.95
				Extracting liquid	0.08	26.13	73.79
Raffinate	50.29	1.52	48.19

As can be seen from Table 1, the n-tetradecane content in the extract was only 0.08%, the 1-tetradecene content was 26.13%, the n-tetradecane content in the residue was 50.29%, and the 1-tetradecene content was only 1.52%, indicating that the eluent was used to achieve efficient separation of n-tetradecane and 1-tetradecene from the starting material, and that the 1-tetradecene yield was 26.13/(26.13+1.52) ═ 94.5%.

Example 2

The raw material to be separated in this example is a C14 component, and the eluent is a C16 alkane.

C16 eluent: n-hexadecane, prior to the separation of the alkane and alkene, the eluate is pretreated to remove poisons (e.g., oxygen-containing organic compounds, benzene, water, etc.) therein that may cause adsorption failure.

The separation of the C14 feed was carried out in a simulated moving bed unit using C16 eluent. Simulated moving bed operating conditions: the adsorbent adopts molecular sieve adsorbent and modified molecular sieve adsorbent not limited thereto; the temperature operation temperature is 100 ℃; the operating pressure was 1 MPa.

The distribution of C14 in the simulated moving bed adsorption tube is shown in FIG. 3. The results of the chromatographic analysis are shown in Table 2.

TABLE 2

Material(s)	N-tetradecane (%, w/w)	1-tetradecene (%, w/w)	Eluent (content (%, w/w)
				Raw materials	29.95	70.05	-
Eluent	-	-	99.95
				Extracting liquid	0.09	26.12	73.79
Raffinate	50.26	1.56	48.18

As can be seen from Table 2, the n-tetradecane content in the extract was only 0.09%, the 1-tetradecene content was 26.12%, the n-tetradecane content in the residue was 50.26%, and the 1-tetradecene content was only 1.56%, indicating that the eluent was used to achieve efficient separation of n-tetradecane and 1-tetradecene from the starting material, and that the 1-tetradecene yield was 26.12/(26.12+1.56) ═ 94.36%.

Example 3

The raw material to be separated in this example is a C10 component, and the eluent is a C16 alkane.

C10 raw material: n-decane 30% (w/w), 1-decene 70% (w/w), and the feedstock was pretreated to remove poisons (e.g., oxygen-containing organic compounds, benzene, water, etc.) therein that may cause adsorption failure prior to the separation of the alkane and the olefin.

The separation of the C10 feed was carried out in a simulated moving bed unit using C16 eluent. Simulated moving bed operating conditions: the adsorbent adopts molecular sieve adsorbent and modified molecular sieve adsorbent not limited thereto; the temperature operation temperature is 180 ℃; the operating pressure was 0.5 MPa.

The distribution of C10 in the simulated moving bed adsorption tube is shown in FIG. 4. The results of the chromatographic analysis are shown in Table 3.

TABLE 3

Material(s)	N-decane (%, w/w)	1-decene (%, w/w)	Eluent (content (%, w/w)
				Raw materials	29.92	70.08	-
Eluent	-	-	99.93
				Extracting liquid	1.23	22.23	76.54
Raffinate	48.87	3.12	48.01

As can be seen from Table 3, the n-decane content in the extract was 1.23% and the 1-decene content was 22.23%, the n-decane content in the raffinate was 48.87%, and the 1-decene content was 3.12%, indicating that the separation of n-decane and 1-decene from the raw material was achieved by the eluent, and that the 1-decene yield was 22.23/(22.23+3.12) ═ 87.69%.

Example 4

The raw material to be separated in the example is a C10 component, and the eluent is C14 and C16 alkane.

C14 and C16 eluents: n-tetradecane 50% (w/w) and n-hexadecane 50% (w/w), and the eluate is pretreated to remove poisons (e.g., oxygen-containing organic compounds, benzene, water, etc.) therein, which may cause adsorption failure, before the separation of the alkane and the alkene is performed.

The separation of the C10 feedstock was carried out in a simulated moving bed unit using C14 and C16 eluents. Simulated moving bed operating conditions: the adsorbent adopts molecular sieve adsorbent and modified molecular sieve adsorbent not limited thereto; the temperature operation temperature is 20 ℃; the operating pressure was 0.5 MPa.

The distribution of C10 in the simulated moving bed adsorption tube is shown in FIG. 5. The results of the chromatographic analysis are shown in Table 4.

TABLE 4

Material(s)	N-decane (%, w/w)	1-decene (%, w/w)	Eluent (content (%, w/w)
				Raw materials	29.92	70.08	-
Eluent	-	-	99.87
				Extracting liquid	0.47	21.41	78.12
Raffinate	46.13	1.25	52.62

As can be seen from Table 4, the n-decane content in the extract was 0.47% and the 1-decene content was 21.41%, the n-decane content in the raffinate was 46.13%, and the 1-decene content was 1.25%, indicating that the separation of n-decane and 1-decene from the raw material was achieved by the eluent, and that the 1-decene yield was 21.41/(21.41+1.25) ═ 94.48%.

Example 5

The raw material to be separated in the example is a C14 component, and the eluent is C10 and C12 alkane.

C10 and C12 eluents: n-decane 50% (w/w), n-dodecane 50% (w/w), and the eluate was pretreated before the separation of the alkane and the alkene to remove poisons (e.g., oxygen-containing organic compounds, benzene, water, etc.) therein, which may cause adsorption failure.

The separation of the C14 feedstock was carried out in a simulated moving bed unit using C10 and C12 eluents. Simulated moving bed operating conditions: the adsorbent adopts molecular sieve adsorbent and modified molecular sieve adsorbent not limited thereto; the temperature operation temperature is 190 ℃; the operating pressure was 1.5 MPa.

The distribution of C14 in the simulated moving bed adsorption tube is shown in FIG. 6. The results of the chromatographic analysis are shown in Table 5.

TABLE 5

Material(s)	N-tetradecane (%, w/w)	1-tetradecene (%, w/w)	Eluent (content (%, w/w)
				Raw materials	29.95	70.05	-
Eluent	-	-	99.83
				Extracting liquid	0.31	20.88	78.81
Raffinate	45.93	1.12	52.95

As can be seen from Table 5, the n-tetradecane content in the extract was 0.31% and the 1-tetradecene content was 20.88%, the n-tetradecane content in the residue was 45.93% and the 1-tetradecene content was 1.12%, and it was found that the separation of n-tetradecane and 1-tetradecene from the starting material was achieved by the eluent, and the 1-tetradecene yield was 20.88/(20.88+1.12) ═ 94.91%.

Example 6

In the embodiment, the raw material to be separated is a component C10, and the eluent is composed of C14-C16 alkane.

C14-C16 eluent: 33% (w/w) of n-tetradecane, 33% (w/w) of n-pentadecane, and 34% (w/w) of n-hexadecane, before the separation of alkane and alkene, the eluate is pretreated to remove poisons (e.g., oxygen-containing organic compounds, benzene, water, etc.) therein, which may cause adsorption failure.

The separation of the C10 feedstock was carried out in a simulated moving bed apparatus using C14-C16 eluents. Simulated moving bed operating conditions: the adsorbent adopts molecular sieve adsorbent and modified molecular sieve adsorbent not limited thereto; the temperature operation temperature is 75 ℃; the operating pressure was 1.4 MPa.

The distribution of C10 in the simulated moving bed adsorption tube is shown in FIG. 7. The results of the chromatographic analyses are shown in Table 6.

TABLE 6

Material(s)	N-decane (%, w/w)	1-decene (%, w/w)	Eluent (content (%, w/w)
				Raw materials	29.92	70.08	-
Eluent	-	-	99.77
				Extracting liquid	0.51	20.43	79.06
Raffinate	45.14	1.79	53.07

As can be seen from Table 6, the n-decane content in the extract was 0.51% and the 1-decene content was 20.43%, the n-decane content in the raffinate was 45.14%, and the 1-tetradecene content was 1.79%, indicating that the separation of n-decane and 1-decene from the starting material was achieved by the eluent, and that the 1-decene yield was 20.43/(20.43+1.79) ═ 91.94%.

Example 7

In the embodiment, the raw material to be separated is a component C14, and the eluent is composed of C10-C12 alkane.

C10-C12 eluent: 33% (w/w) of n-decane, 33% (w/w) of n-undecane, and 34% (w/w) of n-dodecane, and the eluate was pretreated before the separation of the alkane and the alkene to remove poisons (e.g., oxygen-containing organic compounds, benzene, water, etc.) therein which may cause adsorption failure.

The separation of the C14 feedstock was carried out in a simulated moving bed apparatus using C10-C12 eluents. Simulated moving bed operating conditions: the adsorbent adopts molecular sieve adsorbent and modified molecular sieve adsorbent not limited thereto; the temperature operation temperature is 15 ℃; the operating pressure was 2 MPa.

The distribution of C14 in the simulated moving bed adsorption tube is shown in FIG. 8. The results of the chromatographic analyses are shown in Table 7.

TABLE 7

Material(s)	N-tetradecane (%, w/w)	1-tetradecene (%, w/w)	Eluent (content (%, w/w)
				Raw materials	29.96	70.04	-
Eluent	-	-	99.77
				Extracting liquid	0.41	20.34	79.25
Raffinate	46.13	1.91	51.96

As can be seen from Table 7, the n-tetradecane content in the extract was 0.41%, the 1-tetradecene content was 20.34%, the n-tetradecane content in the raffinate was 46.13%, and the 1-tetradecene content was 1.91%, indicating that the separation of n-tetradecane and 1-tetradecene from the starting material was achieved by the eluent, and that the yield of 1-tetradecene was 20.34/(20.34+1.91) ═ 91.42%.

Comparative example 1

The raw material to be separated in this example is a C10 component, and the eluent is a C20 alkane.

C20 eluent: n-eicosane, prior to separation of the alkane and alkene, is pretreated with eluent to remove poisons (e.g., oxygen-containing organic compounds, benzene, water, etc.) that may cause adsorption failure.

The separation of the C10 feed was carried out in a simulated moving bed unit using C20 eluent. Simulated moving bed operating conditions: the adsorbent adopts molecular sieve adsorbent and modified molecular sieve adsorbent not limited thereto; the temperature operation temperature is 250 ℃; the operating pressure was 2 MPa.

The distribution of C10 in the simulated moving bed adsorption tube is shown in FIG. 9. The results of the chromatographic analysis are shown in Table 8.

TABLE 8

Material(s)	N-decane (%, w/w)	1-decene (%, w/w)	Eluent (content (%, w/w)
				Raw materials	29.92	70.08	-
Eluent	-	-	99.77
				Extracting liquid	1.45	12.13	86.42
Raffinate	38.67	7.69	53.64

As can be seen from Table 8, the n-decane content in the extract was 1.45% and 1-decene content was 12.13%, the n-decane content in the raffinate was 38.67% and 1-decene content was 7.69%, and it was found that the separation of n-decane and 1-decene from the raw material was achieved by using the eluent, the 1-decene yield was 12.13/(12.13+7.69) ═ 61.20%, the separation effect was poor, and the eluent (desorbent) ratio in the extract was increased (to 86.42%), which was economically poor.

Comparative example 2

The raw material to be separated in this comparative example was a C10 component, and the eluent was a C11 alkane.

C11 eluent: n-undecane, prior to the separation of the alkane and alkene, the eluate is pretreated to remove poisons (e.g., oxygen-containing organic compounds, benzene, water, etc.) therein that may cause adsorption failure.

The separation of the C10 feed was carried out in a simulated moving bed unit using C11 eluent. Simulated moving bed operating conditions: the adsorbent adopts molecular sieve adsorbent and modified molecular sieve adsorbent not limited thereto; the temperature operation temperature is 0 ℃; the operating pressure was 1 MPa.

The distribution of C10 in the simulated moving bed adsorption tube is shown in FIG. 10. The results of the chromatographic analyses are shown in Table 9.

TABLE 9

Material(s)	N-decane (%, w/w)	1-decene (%, w/w)	Eluent (content (%, w/w)
				Raw materials	29.91	70.09	-
Eluent	-	-	99.92
				Extracting liquid	8.23	17.74	77.03
Raffinate	29.16	21.12	49.72

As can be seen from Table 9, the n-decane content in the extract was 8.23% and the 1-decene content was 17.74%, the n-decane content in the raffinate was 29.16% and the 1-decene content was 21.12%, and it was found that the effect of the eluent on the separation of n-decane and 1-decene from the raw material was not satisfactory, the 1-decene yield was only 17.74/(17.74+21.12) ═ 45.65%, and the 1-decene content in the raffinate was too high.

The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are only exemplary embodiments of the present invention and are not intended to limit the present invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A process for the separation of alkanes and alkenes using a simulated moving bed comprising elution with an eluent, characterized in that the eluent is a normal alkane having a difference in carbon number from the alkene in the feed to be separated of more than 1 and less than 7 (e.g. 2, 3, 4, 5 or 6), preferably more than 1 and less than 5 (e.g. 2, 3 or 4).

2. The method of claim 1, wherein the n-alkane is a n-alkane.

3. The method according to claim 1, wherein the normal alkane is a mixture of normal alkanes each having a carbon number greater than or less than the carbon number of alkane and alkene in the feedstock to be separated.

4. The method according to claim 1, wherein the operating temperature is 0 to 250 ℃ (e.g. 20 ℃, 50 ℃, 80 ℃, 100 ℃, 150 ℃ or 200 ℃), preferably 20 to 100 ℃; the operating pressure is 0 to 2MPa (for example, 0.2MPa, 0.5MPa, 0.8MPa, 1MPa or 1.5MPa), preferably 0 to 1 MPa.

5. A method according to claim 1, characterized in that the method comprises the step of removing impurities affecting the adsorption effect in the eluent and the raw material to be separated.

6. The process of claim 1, comprising the step of separating and recovering the eluent in the extract and the raffinate.

7. The process of claim 1, wherein the simulated moving bed comprises an adsorption zone, a purification zone, and a desorption zone.

8. The method of claim 7, wherein the simulated moving bed further comprises a buffer zone.